Scien4Tech

Mach Number and its Significance

2019-02-16T16:04:00.000+05:30

Mach number.

Mach number is a dimensional less number. It is the ratio of fluid to the velocity of the sound in that fluid. It was named after the Ernst Mach he is the person behind the Mach number. If the Mach number is related to the object especially aircraft the Mach number is defined as, the ratio of the velocity of the object relative to the fluid and the velocity of sound in that fluid.

Mach number is used to analyze fluid flow dynamics problem where the compressibility is a significant factor.

Mathematically it is expressed as –

M= speed of object /speed of sound

M= V/C

Where,

M= Mach number

V= speed of the aircraft

C= speed of the sound

Subsonic

If the Mach number less than one (M<1): In this case, the speed of the object is less than the sound speed.

Supersonic.

If the Mach number more than one (M>1): In the supersonic speed, the object speed is more than the sound speed.

Transonic

If the Mach number is equal to one (M=1):

In transonic speed, the speed of the object is nearly equal to the speed of the sound.

Hypersonic speed (M>>1):

When the speed of the object is much higher than the speed of the sound in the same medium is called hypersonic speed.

The significance of Mach number

The Mach number is used to describe the speed of aircraft in terms of the speed of sound. If the aircraft speed is equal to the speed of sound then the Mach number would be 1.

Example problem,

An aircraft flies at speed 700 mph at an altitude of 36000 ft. The surrounding temperature is -60 ^oF.

The speed of the aircraft can be calculated as-

v = (700 miles/hr) (5280 ft/miles) / (3600 sec/hr)

= 1026.67 ft/sec

The Mach number can be calculated as-

M = (1026.67 ft/s) / (980 ft/s)

= 1.047 >1

The aircraft is flying at supersonic speed.

Working Principle of Cochran Boiler.

2019-01-27T18:24:00.000+05:30

Cochran Boiler

The Cochran boiler is also called a fire tube boiler. cochran boiler workes on the principle of heat convection. In cochran boiler, the hot gases are being passed through the fire tube running in the sealed container filled with water. The locomotive boiler is self-propelled and the power is being supplied by the diesel, steam or electricity. This type of steam engine has been used in the railway for a long time. The locomotive boiler is consisting of vertical cylinder shell the top of the cylinder is of dome-shaped. This dome shape provides enough space for steam which is produced on heating. Basically, the water is being heated in a high amount at high temperatures which produce a high amount of steam which is used to do mechanical work. The hemispherically shaped furnace is provided to burn the fuel mostly coal is used. Fuel is kept on the grate to burn the fuel easily and ash is then settled in the ash pit. Fire bricks are used for lining as shown in the figure to overcome with the heat loss. On the burning of the fuel, it produces a large amount of smoke that has to be expelled outside for that chimney is provided. When the heat is generated, it heated the fire tube which is filled with flue gases. this flue gases used to heat the water surrounded by the fire tube. all they are of equal dimensions and is kept in a horizontal position. In this process the coal has to feed periodically to make the heating process continues, fire door is provided to feed the coal periodically. The safety valve is used in an emergency when the steam pressure exceeds its limit then it is being opened to release the excess amount of steam. Flue pipe is provided to heat from the furnace to the combustion chamber.

So many safety kinds of stuff are used in the boiler, a fusible plug is provided at the top of the combustion chamber. When the boiler temperature exceeded the safe working limit then it gets melted and stops the fire. Usually, the fusible plug is made up of aluminium and zinc metal. The blow of cock is used to blow of the impurity, mud and sediment from the boiler.

To deal with any boiler safety must be the first priority because silly mistakes are enough to destroy the valuable thing even can catch the fire burn the whole plant along with human being.

Cochran boiler

Working:

On the burning of the fuel in the furnace, it produces a large amount of heat in the form of flue gases. This flue gases entered in the flue pipe and goes to the combustion chamber. Fire tubes are placed horizontally and it is surrounded by the water completely. Flue gases enter in the fire tube pipe and heated the water and form the steam. Formed steam is being kept in the steam chamber.

To produce the steam water has to supply uniformly to the shell and it is controlled by the feed check valve. When the flue gases supplies boiler heated up and the cold water settled down and steam flow over it between the fire tube. Produced steam is kept in the dome shape chamber on the requirement it is supplied to anti priming pipe where water droplets are filtered.

Advantages

Less floor area is required.
Construction cost is less.
It can easily move to different locations, semi-portable.
It has a self-contained furnace.
Easy to operate.
Higher volume to areas ratios.

Disadvantage

The rate of steam generation is less.
Corrosion and scale formation takes place.
Overheating problem.
Periodic cleaning is required and it is difficult to clean all the parts.

Application

Railway and marine

Computer Integrated Manufacturing and Automation

2018-12-14T00:11:00.001+05:30

A production system is the group of people, the collection of equipment and procedures organizing to achieve manufacturing operation of a company. Manufacturing system has adopted a computer to improve the manufacturing process. Implementation of the computer not only simplified many if the traditional manufacturing process but also made it almost impossible for the manufacturing industry to survive in the modern era without it.
The requirement of the production system.

1. Production machine

2. Material handling system

3. Computer control system

4. Human resource

5. Automation

It is defined as the technology concern with the application of mechanical, electrical, electronic and the computer-based system to operate and control the production.

When demand is more in the market, then it is very challenging for the company to produce that much of products within the specified time with the quality products, so it is very difficult to achieve manually. Industrial automation is the use of control system, such as the computer or industrial robot and information technology for handling the different process and machinery in the industry to replace the human being and produce the product in mass with standard quality. Automation has been achieved by various means including mechanical, hydraulic and pneumatics, electrical and electronics sometimes individually and usually in a combination of all. In the modern factory, aerospace and aviation industry typically use this combined technique.
Advantages of automation:-

1. Labour Saving

2. Minimize electricity use.

3. Improves quality of the product

4. Increase the accuracy and precision.

5. Computer Integrated Manufacturing:

Computer integrated manufacturing was introduced by Dr Joseph Harrington in his book bearing that name in 1974. Until 1970 the most aggressive and successful automation was seen in the production process.
The word computer integrated manufacturing denotes the use of a computer system to design the products, plan the production, and control the operation and to perform the various business-related functions needed in a manufacturing process. Discrete parts manufacturing used high mechanised machines that were driven and controlled by cams and complex devices such as automatic screw machines. Computer integrated manufacturing start with the development of the product concept and includes product design and specifications and extend through production, delivery and fast sales activities.
The constituent part of CIM.

1. Marketing

Ø Marketing used to estimate the manufacturing cost to assess the economic viability of the product.

Ø Projection of manufacturing quantities.

Ø Strategies for marketing the product.

2. Product Design.

Ø This department established the initial database for production of a proposed product.

Ø Complex design is usually carried out by several teams working simultaneously across the world.

Ø Design process creates the database required to manufacture the parts.

3.Planning.

Ø Planning involves several subsystems dealing with material, facility, process, tool, manpower, capacity scheduling, outsourcing assembly, inspection and logistics.

4.Purchase

Ø This department deals with the placing the purchase orders, follow up, ensure quality in the production process for the vendor, receive the items, arrange for inspection and supply the items to the stores.

5.Finance

Ø This department deals with the resources pertaining to money.
Planning of investment, working capital, and cash flow control.
Allocation of the fund is the major task of the finance department.

Advantages of CIM

1. Lower manufacturing lead time

2. The flexibility of the manufacturing process.

3. Increase productivity.

4. Improve the quality of the product

5. The overall cost of the manufacturing can be reduced

6. Inventory cost reduces

7. Reduces product defects.

Numerical Control
It is the system in which the actors are controlled by direct insertion of numerical data at some point. The system must automatically interpret at least some portion of this data.
Numerical control technology emerged in the mid 20th century. The real boom came in the form of CNC, in the year 1972 and decade later introduction of the affordable microcomputer. The instructions are the combination of the alphabets, digits and selected symbol. All instructions are written in a logical order and a predetermined form. The collection of all instructions necessary to machine a part is called as NC program.
Types of NC system

1. Traditional Numerical Control

2. Computer Numerical Control

3. Distributed Numerical Control

Traditional Numerical Control
It is also called NC machine tools. It has hardwired control, where control is accomplished through the use of punched tapes or cards. Taped tend to wear and become dirty thus so many problems in the production process.
Computer Numerical Control
It is referred to a system that has a local computer store all required Numerical data, while CNC was used to enhance tapes for a while. Eventually allowed the use of other storage media, magnetic tapes and hard disk. The system can store and execute a number of large programs and also allows editing program.
On CNC machine the function of feed rate drives is to provide motion to the slide as per the motion command. Since the degree of accuracy requirements are high, the feed drive should have high efficiency and response. CNC Control is the heart of the CNC machines. The early CNC Control was developed for simple application in turning machining centre and grinding. But with increased capabilities in a modern machine tool such as higher spindle speed, higher rapid transverses and more number of axes, CNC system has been developed to meet these needs.
Advantages of CNC

1. Accurate costing and scheduling

2. Less scrap

3. Reduced inspection process

4. Reduced lead time

5. Setup time reduction

6. Flexibility in the change of design

7. Longer tool life.

How Does Carburettor works

2018-11-05T17:23:00.000+05:30

How Does Carburettor works?

Introduction

The combustion of the fuel with oxygen in the combustion chamber provides the energy necessary to drive the piston. In the S.I engine the liquid are generally mixed prior to their arrival in the combustion chamber. The process of preparing this mixture is called as carburetion.

In the engine, the desired air-fuel ratio means that gives the maximum economy. Actual air-fuel mixture requirements in an operating engine vary under variable load and speed condition. The air-fuel ratio must be changed based on whether the maximum economy or maximum power is required.

A carburettor is a device which is used in the vehicle to prepare a homogeneous mixture of air and fuel for the working of the engine.

The main function of a carburettor are.....

1. Combine gasoline and air and produce a high combustible mixture.

2. Regulate the air-fuel ratio

3. maintain the engine speed.

working

Liquid fuel is supplied to the carburettor from the fuel tank system which consists of the fuel supply tank, fuel pump, lines and filter. Air is drawn into the carburettor from the atmosphere during suction in the engine cylinders. Most of the air engine induct the air directly into the carburettor through an air cleaner. The carburettor supplies air-fuel mixture to the engine cylinders through intake manifold and quantity of mixture entering the cylinder is regulated by the throttle.

Choke
It usually happens, when the vehicle doesn't get started, and word choke is used but what is it actually,
To start the cold engine, a rich mixture is needed. To provide the rich mixture, choke valve is fitted in the air intake passage of the carburettor. The choke valve is in the form of a circular disc like the throttle valve. This choke is operated to shut off partially the supply of air to the carburettor. During the suction stroke, less amount of air and the more amount of fuel is sucked and a rich mixture is obtained. Immediately after starting the cold engine the choke valve should be open for full air supply.

Venturi

A venturi is a narrow space in the cylindrical air horn, through which the air passes. As the same amount of air must pass through every point in the air horn, its velocity will be greatest at the narrow point. The more the area is reduced, the greater will be the velocity of air.

The spray of gasoline from the nozzle an air entering through the venturi are mixed together in the mixing chamber which is just below the discharge jet. The mixture passes through the intake manifold into the cylinder.

Throttle valve

It is a circular disc located in the mixing chamber of the air horn. It can be tilted to open or close the air horn to allow more or less air to flow through it. When it is tilted to open, more air passes the venturi sucking more fuel, thus more amount of air-fuel mixture goes to the cylinder. The engine develops more power and tends to run faster. When the throttle valve is tilted to close, less air passes the venturi sucking less fuel, thus less amount of air-fuel mixture goes to the cylinders. The engine develops less power and tends to run slowly.

Metering system

As the engine speed increases beyond the certain limit, suction also increases. The flow of the fuel from the jet increases faster than the corresponding flow of air. Thus mixture becomes richer. To maintain the correct air-fuel mixture at high speed.

Advantages

Improves atomization
Better fuel distribution
Smooth idle
Improves power and reduce emissions
It allows use of inferior fuels.
Maintenances cost is less and easy repair.
Simple and Overall cost is less.

Disadvantages

More air emissions than the fuel injector
To start the cold engine is difficult.
Complete combustion of is a challenge.
Spark plug fouling issue is very common.

Turbocharger

2018-11-03T15:34:00.001+05:30

Introduction

To run an automobile engine, like diesel or petrol, the fuel from the tank must reach the engine cylinder by some means. In the petrol engine, the fuel(petrol) from the fuel tank reaches through the fuel pump, filter and carburettor to the engine. In the diesel engine, there is no need of carburettor, the diesel is injected into the engine cylinders by an injector.

The power generated by the IC engine is directly related to the compression force exerted on the air-fuel mixture. If the compression is greater, greater the output of the engine. There are two approaches which can be used to increase the engine compression. One is to modify the internal arrangement of the engine to increase the normal compression ratio. The second method is and it is a less expensive way to increase the mixture compression without physically changing the shape of the combustion chamber is to simply increase the quantity of the intake charge.

There are two artificially methods to increase the amount of air flow into the engine are

Turbocharger

Supercharger

Turbocharger

Turbochargers are used to increase engine power by compressing the air that goes into the chamber. Increased power comes from the additional fuel that the denser air accommodate. Nowadays turbochargers are the most popular method of increasing engine compression. The turbochargers do not require a mechanical connection between the engine and the pressurized pump to compress the intake gases. Exhaust gas is a waste product, the energy develop by the engine is said to be free since it theoretically does not rob the engine of any of the power it helps to produce.

Working

It consists of the turbine housing, turbine wheel, compressor housing, compressor wheel and bearing housing. When the engine is running the exhaust gases leaving the exhaust valve to enter into the exhaust manifold and redirect into the turbine housing. In turbine housing, hot gases strike the fins or blade on the turbine wheel and make it rotate. A turboshaft connects turbine wheel to compressor wheel.

turbocharger

The turbocharger is located to close to the exhaust manifold.A fumes pipe keeps running between the motor ventilation system and the turbine lodging to convey the fumes stream to the turbine wheel. One more pipe is connected to the compressors housing intake to an injector throttle body.

The turbocharger is darted to the ventilation system of the motor. The fumes from the chamber turn the turbine, which works like a gas turbine motor. The turbine is associated with a pole to the blower, which is Located between the air channel and the admission complex. The blower pressurized the air going into the cylinder. The fumes from the chamber goes through the turbine sharp edges, making the turbine turn. The blower is a kind of radiating pump. It attracts the air at the focal point of its cutting edges and excursions it outward as it turns. Almost 40% of the warmth vitality provided to the motor goes into the fumes and will be squandered. A piece of this vitality could be used to drive a gas turbine which thus runs a blower and subsequently results in the supply of more air to the motor. This lifts the motor power and builds warm effectiveness.

Advantages

Reduces specific fuel oil consumption.
Improves mechanical and thermal efficiency.
It uses the unused energy contained in the hot exhaust gases.
Increase the air percentage in the air-fuel mixture.
No drive required for the engine to run.
Very less moving parts.
Smaller and lighter than mechanical blowers.
Increase the horsepower

Disadvantages

It takes much time to spool up and provide the useful boost.
Turbocharger gets heated up very quickly, so coolant is required.
Power surge, cause some instability of the car.

Hall Effect Sensors and its Functional Area.

2018-10-19T17:05:00.002+05:30

Hall Effect Sensors.

This effect was discovered by E.R. Hall in 1879 and is called the Hall effect. Hall effect sensors are the device which is activated by an external magnitude field. When the magnetic flux density around the sensor exceeds a certain pre- threshold, the sensor detects it and generate an output voltage called the Hall Voltage.

We know that a magnetic field has two important characteristics flux density and polarity. The output signal from a Hall effect sensors is the function of the magnetic field density around the device. When a beam of charged particle passes through a magnetic field, forces act on the particle and the beam deflected from its straight line path. A current flowing through a conductor is like a beam of moving charges and thus can be deflected by a magnetic field.

Working Principle

Hall Effect Sensors consists of a thin piece of rectangular p-type semiconductor material such as GaAs, indium arsenide passing a continuous current through itself. When the device is placed within a magnetic field, the magnetic flux line exerts a force on the semiconductor material which deflects the charges carries, electrons and holes, to either side of the semiconductor slab. As these electron and holes move sideward a potential difference is produced between the two sides of the semiconductor material by the build-up of these charges carries. Then the movement of the electron through the semiconductor materials affected by the presence of an external magnetic field which is at the right angle to it and this effect is greater in a flat rectangular shaped material. The Hall effect provides information regarding the types of magnetic poles and the magnitude of the magnetic field. Hall effect sensors are available with either linear or digital outputs. The output signal for linear sensors is taken directly from the output of the operational amplifiers with the output voltage being directly proportional to the magnetic field passing through the Hall sensors.

Applications

Hall Effects sensor is activated by a magnetic field and in many application, the device can be operated by a single permanent magnet attached to a moving device. There are many different types of magnet movement such as Head on, sideways, push-pull etc sensing movements.

The Hall effect sensors are immune to environmental contaminants and can be used under severe service conditions. Such a sensor can be used as position, displacement and proximity sensor if the object being sensed is fitted with a small permanent magnet. Can be used to determine the level of fuel in an automobile fuel tank. A magnet is attached to a float and as the level of fuel changes so that float distance from the Hall sensor changes. The results are a Hall Voltage output which is a measure of the distance of the float from the sensor and hence the level of the fuel in tank determined.
Another application of hall effect sensors is in the brushless D.C. Motors. With such motors, it is necessary to determine when the permanent magnet rotor is correctly aligned with the winding on the stators so that the current through the winding can be switched on at the right instant to maintain the rotor rotation.

Ideal Behavior of a Sensor/Transducer.

2018-10-19T13:15:00.001+05:30

Ideal Behavior of a Sensor/Transducer.

Mechatronics design engineer must be knowing the capabilities and shortcomings of a transducer or measurements system to properly assess it's performance. There are a number of performance-related parameters of a transducer or measurement system. Sensor specifications inform the engineer and the user about the deviation from the ideal behaviour of the sensor.

The following terms are used to define the performance of the transducer and often measurement System as a whole. The design process begins with a need form, perhaps a customer or clients. This may be identified by market research Being used to establish the need for potential customers.

Range

The range of a transducer define the limits between which the input can vary. The span is the maximum value of the input minus the minimum value.

Error

The error is the difference between the results of the measurements and the true value of the quantity being measured. For example, if the measurements system gives a temperature reading of 45^0 C when the actual temperature is 42^0 C then the error is +3^0C.

Accuracy

Accuracy is the extent to which the value indicated by a measurements system might be wrong. It is thus the summation of all the possible error that is likely to occur as well as the accuracy to which the transducer has been calibrated.

Sensitivity

The sensitivity is the relationship indicating how much output here is per unit input. There can be the sensitivity of the transducer to temperature changes in the environment or perhaps fluctuations in the main voltage supply.

Hysteresis

The transducer can give different output from the same value of the quantity being measured according to whether that value has been reached by the continuous increasing change or a continuously decreasing change.

Stability

The stability of the transducer is its ability to give the same output when when used to measure a constant input over a period of time. The term drift is often used to describe the change in output that occurs over time. Zero drift is used for the change that occurs in output when there is zero input.

Dead band/Time

The dead band or dead space of a transducer is the range of input values for which there is no output. The dead time is the length of time from the application of an input until the output begins to respond and change.

Resolution

When the input varies continuously over the range, the output signal for some sensor may change in small steps. Example potentiometer. The resolution is the smallest change in the input values that will produce a considerable change in the output.

Non-linearity error

For many transducers, the linearity relationship between the input and output is assumed over the working range. in some transducer, however, have a truly linear relationship and thus the error occurs as a result of the assumption of linearity. This error is defined as the maximum difference from the straight line. various methods are used for the numerical expression of the non-linearity error. The difference occurs in determining the straight line relationship against which the error is specified.

Repeatability

The term repeatability of the transducer is used to describe it's ability to give the same output for repeated application of the describe the same input values. The error resulting from the same output not being given with repeated applications is usually expressed as a % of the full range output.

Types of Light Sensor and its Application.

2018-10-17T17:25:00.000+05:30

Light Sensor

light sensors are semiconductors device and this is operation is based on the change in the resistance and current flow in the circuit when the light falls on them.

there are three type of light sensor:-

Photodiode
Phototransistor
Photoresistor

photodiode is semiconductor junction diodes which are connected into a circuit in reverse bias, so giving a very high resistance. With no incident light, the reverse current is almost negligible and is termed the dark current.when the light fall on the junction, extra hole electrons pair are produced and there is an increase in the reverse current and the diode resistance drops.

The photodiode is two terminal electronic devices which when exposed to light the current start flowing in the diode. It is operated in reverse bias. Basically, it converts light energy into electrical energy.

Working

The junction of the diode is. Illuminated by the light source, the photons strike the junction surface. The photons impart their energy in the form of light to the junction. Due to which electrons from valence band get the energy to jump into the conduction band and contribute to the current. The reverse current is very nearly proportional to the intensity of the light. For example, the current in the absence of light with a reverse bias of 3 volts might be 25uA and when illuminated by 25000 lumens /m^2 the current rises to 375 uA . The resistance of the device with no light is 120k ohm and with light is 8k ohm. A photodiode can thus be used as a variable resistance device controlled by the light incident on it. Photodiode has the very high response to the light.

Application

photodiodes are condensed as one of the significant optoelectronics devices which is extensively used in the optical fibre communication system.
it is used in the character recognition technique and IR remote control circuits.

Phototransistor

The phototransistors have light-sensitive collector base p-n junction. When there is no incident light there is a very small collector to emitter current. When light is incident, a base current is produced that is directly proportional to the light intensity. this leads to the production of a collector current which is then a measure of the light intensity.

Working

The two arrow point towards phototransistor indicate that the phototransistors are triggered by the light rays incident on it .the output of the phototransistors is taken from the emitter terminal and the light rays are allowed to enter the base region. the magnitude of the photocurrent generated by the phototransistors depends on the light intensity of the light falling on the transistor.

Application

Counting system
Encoder sensing
Object detection
Printer and optical control remote
Light detectors.

Photoresistor

A photoresistor has a resistance which depends on the intensity of the light which is falling on it.decreases linearly as the intensity increases. The cadmium sulphide photoresistor is the most responsive to light having the wavelength shorter than about 515 nm and the cadmium selenide photoresistor for wavelength less than about 700nm.

Working

When the light falls on the photoresistor, some of the valence electron, which absorbs energy from the light and breaks the bonding with the atoms. the valence electron which breaks the binding with the atom is called the free electron. Because when the light energy falls on it, material get heated up and the electrons movement gradually increases, again if the energy increase then the electrons comes out from its threshold boundaries.

Application

Streetlight
Alarm device
Street solar lamp
Clock radios.

Evolution of Mechatronics in the Modern Technology.

2018-10-11T01:08:00.000+05:30

Evolution of Mechatronics

The term Mechatronics was invented by a Japanese engineer in 1969, as a combination of 'mecha' from the mechanism and 'Tronics' from electronics. now the word has a wider meaning, being used to describe a philosophy in engineering technology in which there is coordinated and concurrently developed, integration of mechanical engineering with electronics and intelligent computer control in the design and manufacture of product and processes. as a result mechatronics products have many mechanical functions replaced with electronic ones. This result in much greater flexibility, easy redesign and reprogramming and the ability to carry out automated data collection.

Definitions

A formal definition of mechatronics is "The synergistic integration of mechanics and mechanical engineering, electronics, computer technology and IT to produce or enhance the products and system".

Mechatronics is the synergistic integration of sensors, actuators, signal conditioning, power electronics, decision and control algorithm, and computer hardware and software to manage the complexity, uncertainty and communication in the engineering system. According to the Mechatronics forum, a precise and common definition is as follows."Mechatronics is the synergistic integration of mechanical engineering with electronics and intelligent control algorithm in the design and manufacture of products processes".products and processes requiring inputs from more than one discipline can be realized through the integration. multidisciplinary is an additive process of bringing multiple disciplines together to bear on a problem.

In recent years, the application of digital microelectronics and computer in design and manufacturing sector has considerably improved productivity and quality of many mechanical products. automation and control method, adopting integrated embedded technology has become relevant to industries, machinery and consumer products. Mechatronics, an enabling discipline has already emerged to cater to the need for sophistication and flexibility and in fact has become a preferred choice for the current generation of the real-time automation and control solution for the traditional mechanical system.

A mechatronics system is no just a marriage of electrical and mechanical system and is more than just a control system; it is a complete integration of all of them in which there is the concurrent approach to the design. In the design of a car, robot, machine tool, washing machine cameras and many other machines. The technological design has become a high-risk endeavour due to the lack of knowledge and experience on interdisciplinary subject and methods. the advanced technological design is highly complex and interdisciplinary nature involving the synergistic integration of mechatronics, photonics, computronics and communication. Technological development and innovation would thus require simultaneous knowledge of discrete fundamentals.

Mechatronics, although still a relatively new term compared with many of the traditional branches of engineering, now appears firmly established. individuals industries and universities around the world are now using the term freely. At the research and development level.

Technical areas are classified under the mechatronics discipline are;

Manufacturing
robotics
Automobiles
Actuation and sensor
Modelling and design
intelligent control
motion control
Vibration and noise control
System integration
Optical electronics

Examples of mechatronic systems

Consider the modern autofocus, auto exposure camera. to use the camera all you need to do is point it the subject and press the button to take the picture. The camera can automatically adjust the focus so that the subject is in focus and automatically adjust the aperture and shutter speed so that the correct exposure is given. you do not need to have to manually adjust focusing and aperture or shutter speed controls.

Job opportunities

Automobiles companies

Aerospace companies

Madox Technology Pvt.Ltd.

Mechatronics Elevator

Systemantics India Pvt.Ltd.

Mechatronics Fze.

Petra mechatronics Middle East Trading LLC

Emirates Mechatronics Engineering Solution.

Salaries

In India: 35k to 45k pm initially

In Abroad: $70,000 to $85,000 annually.

Also Read Mechanical Actuating System Used in Mechatronics.

Functions of Microprocessor and applications.

Gear Mechanism in the Mechanical Actuation system.

2018-10-09T00:34:00.000+05:30

Gear

Gear trains are the mechanism which is very widely used to transfer and transform rotational motion. they are used when a change in speed or torque of a rotation device is needed. For example, the car gearbox enables the driver to match the speed and torque requirement of the terrain with the engine power available.

Gear can be used for the transmission of rotary motion between the parallel shaft and for the shaft which has axes inclined to one another. When two gear is in mesh, the larger gear wheel is often called the spur gear and the smaller one the pinion.

Gear Train

The term gear train is used to describe a series of the intermeshed gear wheel. the term simple gear train is used for a system where each shaft carries only one gear wheel, the overall gear ratio is the ratio of the angular velocities at the input and output shaft.

The terms compound gear train is used to describe a gear train when the two wheels are mounted on the common shaft.

Rotational to translational motion

The rack and pinion is another form of gear, being essentially two intermeshed gears with one having a base circle of infinite radius. such gear can be used to transform either linear motion to rotational motion or vice versa. Another method that has been used for converting rotary motion translational motion is the screw and nut system. With the conventional form of screw and nut, the nut is rotated and moved along the stationary screw.

Ratchet and pawl mechanism

A ratchet is a device that allows linear or rotary motion in only one direction.it is used in rotary machines to index air operated the indexing table. the ratchet pawl mechanisms are consist of a wheel called ratchet, with saw-shaped teeth which engage with an arm called a pawl. the arm is pivoted and can move back and forth to engage the wheel.

The shape of the teeth is such that rotation can occur in only one direction.rotation of the ratchet wheel in a clockwise direction is prevented by the pawl and can only take place when the pawl is lifted. the pawl is normally spring loaded to ensure that it automatically engages with the ratchet teeth.

Belt and chain drives

Belt drives are essentially just a pair of rolling cylinders with the motion of one cylinder being transferred to the other by a belt. belt drives use the friction that develope between the pulleys attached to the shaft and belt around the arc of contact in order to transmit a torque. the transmitted torque is due to the differences in the tension that occurs in the belt during operation. this differences results in a tight side and a slack side for the belt.

As a method of transmitting power between two shafts, belt drives have the advantages that the length of the belt can easily be adjusted to suit a wide range of shaft to shaft distances and the system is automatically protected against overloaded because slipping occurs if the loading exceeds the maximum tension that can be sustained by frictional forces.

Types of belts.

Flat belt: It is in rectangular in shape and cross-section. flat belt has an efficiency of 98% and produces little noise. it can transmit power over the long distance between pulley centre.
Round belt: it has a circular cross-section and is used with groove pulleys.
V-belt: V belt is used with grooved pulleys and is less efficient than the flat belt.
Timing belt: timing belt requires toothed wheels, having teeth which fit into the grooves on the wheels.

Mechanical Actuating System Used in Mechatronics.

2018-10-08T00:35:00.000+05:30

Mechanical Actuating System

Mechanisms are devices which are used to convert the motion from one form to other required forms. examples, transform linear motion into rotational motion, or motion in one direction to move in a direction at a right angle, a linear reciprocating motion into rotary motion, as in the internal combustion engine where the reciprocating motion of the piston is converted into rotation of the crank and hence the drive shaft.

Mechanical elements can include the use of linkage, cams, gear rack-pinion, chain, belt drives. Many of the action which previously was obtained by the use of the mechanism are, however, often now days being obtained as a mechatronics approach by the use of a microprocessor system. The mechatronics approach has resulted in a simplification and often a reduction in cost. while electronics might now be used often for many functions that previously were fulfilled by mechanism, the mechanism might still be used to provide such functions as:

force amplification; given by lever
change of speed; given by gear
a particular type of motion; given by quick return mechanism.

The motion of any rigid body can be considered to be a combination of translation and rotational motion. by considering the three dimensions of space.

Translational motion can be considered to be a movement which can be resolved into components along one or more of the three axes
A rotational motion can be considered as a rotation which has component rotating about one or more of the axes

Degree of freedom and constraints

A body that is free in space can move in three independent, mutually perpendicular directions and rotate in three ways about direction, then it is said to have six degrees of freedom.

The degree number of freedom is the number of components of the motion that are required in order to generate motion. the problem in design is often to reduce the number of degree of freedom and this requires an appropriate number and orientation of the constraints. without any constrain a body would have six degrees of freedom.

The cam shape required to produce a particular motion of the follower will depend on the shape of the cam and the type of the follower used. Cams are the mechanical devices which are used to generate curvilinear or irregular motion of the mechanical elements. they are used to convert rotary motion into oscillatory motion or vice versa. as the cam rotates so the follower is made to rise, dwell and fall, the length of times spent at each of these positions depending on the shape of the cam.

Classification of Cams.

Wedge and flat cams: A wedge cam has a wedge of specified contour and has translational motion. The follower can either translate or oscillate. a spring is used to maintain the contact between the cam and the follower.

Plate cam: The follower moves in a radial direction from the centre of the rotation of the cam. the follower reciprocates or oscillates in a plane normal to the cam axis.

Cylindrical Cam: A cylinder has a circumferential contour cut in the surface and the cam rotates about the axis. the follower motion is either oscillating or reciprocating type.

Applications of Cams:

Cams are widely used in the automation of the machinery, gear cutting machines, screw machine, printing press, textile industry, automobile engine valve

Cams in automatic lathes
Automatic copying machine
I.C engines

Functions of Microprocessor and applications.

2018-10-07T14:30:00.000+05:30

Introduction

It is an integrated circuit designed for use as a central processing unit of a computer. The CPU is the primary and central player in communication with the devices such as memory, input and output. The terms Microprocessor came into existence in the year 1971, when the Intel Corporation of America developed the first microprocessor Intel-4004 it was able to process just 4 bits.

It is the digital device of the processor system which processes the data, fetching the instruction from memory, decoding and executing them. The microprocessor system that we are concerned are used as a control system and it called as embedded microprocessors. It performs certain arithmetic and logical operations to accept data from the input device and send results to the output. it is incorporated the functions of a CPU on a single integrated circuit or few integrated circuits.
The microprocessor system is consist of

Central processing unit.
input-output interfaces.
Memory unit

Buses: Basically it is a communication link between the processing unit and the peripheral devices.

1.Data Bus: it is used to transport a word to or from the CPU and the memory or the output /input interfaces Each wire in the bus carries a binary signal 0 or 1.

2.Address Bus: It carries signals which indicate where data is to be found and so the selection of the certain memory location or input or output ports. Each storage location within a memory device has a unique identification.

3.Control Bus: The signals relating to control activities are carried by the control bus. it is necessary for the microprocessor to inform memory devices whether they are to read data from an input device or write data to an output device.

The constituent part of a microprocessor.

Arithmetic and logic unit(ALU): This unit is responsible for performing the data manipulation and other logical operation on the data.
Register: Internal data that the CPU is currently using is temporarily held in a group of registers while instructions are being executed. these are memory location within the microprocessor and are used to store the information.
Control unit: The control unit performs the most important function in the computer. it controls all other units and also controls the flow of data from one unit to another for performing computations.it generates the timing signals used to fetch a program instruction from memory and execute it. operations involving the microprocessor are reckoned in terms of the number of cycles they take.
Memory Unit: The memory unit in a microprocessor system stores binary data and takes the form of one or more integrated circuits. the data can be program instruction codes or number being operated on. this usually consists of chips of both ROMs and RAMs
Output unit: After processing of the data in the arithmetic and logical unit, the results are displayed to the output world through this unit. the term peripheral devices are used for pieces of equipment that exchange data with a microprocessor system. for the microprocessor to input valid data from an input device, it needs to be certain that the interface chip has correctly latched the input data. it can do this by polling or an interrupt.

Advantages of a microprocessor

Low cost
less heat generation
low power consumption
high speed
Small size
Reliable
Versatile
Portable

Also read Requirement of An Ideal Control System.

Properties of Fluid Used in Fluid Power System.

2018-10-02T15:24:00.000+05:30

Classification of fluids

Ideal fluid: A fluid which is incompressible and is having no viscosity. it is an imaginary fluid, it does not exist.
Real fluid: A fluid which posses viscosity is known as real fluid
Newtonian fluid: In a fluid, in which shear stress is directly proportional to the rate of shear strain
Non- Newtonian fluid: A fluid in which the shear stress is not proportional to the rate of shear strain.
Ideal plastic fluid: A fluid in which shear stress is more than the yield value and shear stress is proportional to the rate of shear strain

Properties of fluid

1. Viscosity:

The viscosity of the fluid is its resistance to flow. The fluid of hydraulic power system is the compromise. if the viscosity of the fluid is too low then the fluid will leak by the internal seal causing a volumetric loss of the efficiency. if the viscosity of the fluid is too high then the fluid is difficult to push through the hoses, fittings and valves causing a loss of mechanical efficiency.

The dynamic viscosity is the shearing resistance of the fluid and it is measured by placing the fluid between two plates and shearing one plates with respect to other.

2. Chemical stability:

It is an important property of the hydraulic fluid. it is defined as the ability of the fluid to resist oxidation and deterioration for long time periods. Under the severe operating condition, the fluid undergoes unfavourable changes. a chemical reaction takes place with a hydraulic component, these reactions result in the formation of sludge, gums, carbon, etc, which clog the openings and cause valve and piston to stick.

3. Cleanliness:

It is a very sensitive factor which received very considerable attention, especially when the hydraulic system used in the aerospace industry because it is extremely sensitive to the contamination. fluid cleanliness is of primary importance because the contaminants can cause malfunction, prevent proper valve seating, cause wear in the component.

4. Anti-wear and lubrication characteristics:

The fluid must be capable of covering the contact surfaces of all the moving parts with a thin continuous lubricating film. the lubricating film may be destroyed as a result of high loading forces, insufficient oil delivery and low viscosity, it leads to wear due to fretting.

5.Compatibility:

In the hydraulic system, different materials are used and all the material has their own properties, so the fluid should be fully compatible with the other material used in the hydraulic system. it should not react chemically with any of these materials nor changes their physical properties.

6. Foaming:

All the fluid contain a certain amount of dissolved air in it. the amount of the dissolved air depends on the temperature and pressure. material based oil can contain 10 to 12 % by volume of dissolved air. as the temperature of the fluid increases or the pressure decreases the dissolved air is liberated and it forms the bubble. when the fluid contains the entrained air return to the reservoir, the air rises to the surface and cause foam. this foam can cause a severe problem. a foam-depressant additive is used to break down of the foam.

How Fluid Power System Works.

2018-10-02T00:43:00.000+05:30

It can be said that fluid power the backbone or muscles that make the industry move. The fluid power system is used to push, pull, rotate, regulate and drive directly or indirectly all the machines of industry. fluid power is the technology that deals with the generation, control and transmission of power using the pressurized fluids. Almost in all the industries process required to move the body from one place to other places, some time to hold the body or object for some manufacturing process, such activities are performed by the prime mover.

whenever we talk about the fluid power system two comes into the picture-

1. Hydraulic system: Fluid based system using the liquid as a transmission medium.

this system uses the liquid such as petroleum oil, water etc. in the earliest fluid used was water hence the name was applied to the system using liquids.

2. Pneumatics system: Gase based system is called a pneumatic system.

In this system gases used are, compressed air, some time nitrogen.

Fluid power is the general term used for both hydraulic and pneumatic system. there are two type of fluid power system.

Fluid transport: it is used to deliver the fluid from one place to another place.
fluid power: it is designed specially to perform work that is accomplished by a pressurised fluid bearing on an operating fluid cylinder or fluid motor.
*Fluid is a substance that can flow or continually deform under the applied shear stress.

Advantages

Simple and accuracy of control: using the simple lever and push button, one can operate the system easily and accurately.
Multiplication and variation of forces: a fluid power system can multiply forces simply and efficiently from a kilogram to several hundreds of ton.
Multiplication control: a single hydraulic pump or air compressor can provide power and control for numerous machine using a valve manifold and distribution system.
Constant force and torque: It is capable of providing a constant torque of force regardless of speed changes.
Low weight to power ratio: the hydraulic system has a low weight to power ratio compared to other systems.
the system is Economical and compact.
The fluid power system is used where the safety is much more important.
Eliminate complicated mechanical trains of gear.

Disadvantages

Hydraulic lines can burst to cause serious human injuries.
Prolong exposure to loud noise.
Fire hazard
Systems are messy.
Physical injury from the high-speed particle.
The hydraulic system is highly corrosive to most of the aircraft material.

Applications

Medical : Medical equipment such as dental drives and human patient simulator, heart assist devices.
Aviation: landing wheel in aircraft, aircraft trolley, luggage loading and unloading system, aileron, flight simulator.
Automobile: hydrostatic transmission, suspension system, power brakes

Requirement of An Ideal Control System.

2018-10-01T19:58:00.002+05:30

There are two major division in the control theory, classical and modern, which have direct implications over the control Engineering. The area of classical control theory is limited to single input and single output system design.
Modern control theory is carried out strictly in the complex or the frequency domain and can deal with the multi-output system.
So many parameters are considered in the design of the control system. Each and every control system are designed to achieve and perform the specific task. so to achieve that particular objective, a control system should satisfy the following requirement.
1. Stability
2. Bandwidth
3. Speed
4. Accuracy
5. Sensitivity
6. Disturbance

Stability:
In the initial condition system parameters do not result in large changes in the system behaviour. Stability is the important parameters of the transient response of a control system.A ideal control system is one which gives bonded output for bounded input. stability in the control system implies that small change in the system input.
Bandwidth:
Basically bandwidth of the control system defined the range of input of that particular system. output of a ideal control system should be consatnt and should give satisfactory output for the input frequency.
Speed:
speed of the control system refers the how fast the output of the system approaches to the required value. speed is measured in terms of the settling time and rise time. an ideal control system should have good speed.
Accuracy:
it just compare the input and the obtained output from the system, how much output is close to input or desire value. an ideal control system should be highly accurate.
Sensitivity:
It is an important parameter that must be considered in the system design. an ideal control system should be insensitive to the variations in the parameters of the system but it should be insensitive to the input command.
Disturbance:
almost all the control system are subjected to the some kind of unwanted or noise during the operation of control system. like wind gust, thermal noise, voltage is very common. therefore to avoid this problem , in the design of a control system, special attention and consideration must be given to the external disturnbance , so that the system is insensitive to noise and disturbance but must be sensitive to the input command.
Controller
Controller is a basic element of a control system which compare the actual value of the plant output with the reference input value to determine the error or deviation and produces proper corrective action taht will reduce the error to a smaller value or tends to zero.Generelly itis known as automatic controllers.
Types of control system:

Proportional controller
Derivative controller
Integral controller
Proportional plus integeral controller
Proportional plus differential controller
Proportional plus differentila plus integral controller
On-off controller

Open loop and closed loop control system.

2018-09-15T00:16:00.000+05:30

Control system:
It is an arrangement of components interconnected in such a way as to regulate, direct itself to obtain a required objective.
Open loop control system:-
An open loop control system is one in which the control action does not depend on the desired output. In the open loop closed loop system, when the input is applied to the control unit which generates the necessary action to control the driver or process which is to be controlled to get the required output. this system is very sensitive to the environment, if there are any changes in the external environment in between the operation, then the desire cannot be achieved.
example: traffic control system, automatic washing machine, electric switch etc.
Advantages

highly accurate
convenient to use when the output is difficult to measure
comparatively more stable.
economical
Bandwidth range is large
low cost
simple in construction

Disadvantages

Frequent calibration is required.
Required skilled operator
Internal disturbance.

Closed loop control system:-

A closed loop control system is one in which the control action depends on the output of the system.in this system, the desired output can be measured and compared with the input of the system using the feedback element. This system is consist of a summing point, take off point, feedback, controller and process. In this system, the output is compared with the input at the summing point and this determines the error based on which control action generated. Difference between the input and output is called as an error. The error signal is used to reduce the error and approaches to the desired output.

Examples: automobile speed control, automatic tank level control system etc.

Advantages

More accurate due to feedback.
Less affected by noise or disturbance
The error detector is present
optimisation is possible
more flexible
No skilled operator is required

Disadvantages

More complex and expensive
the system is complex.
less stable
Required high power system.

Introduction to Non-Destructive Test(NDT)

2018-08-22T01:47:00.000+05:30

Introduction to Non-Destructive Test(NDT)

Non-Destructing Test(NDT) is an analysis technique used in science and manufacturing industries for the inspection, testing, evaluating properties of the material and the assemblies for discontinuities without causing damage.

it was a big challenge for manufacturing industries to ensure the performance and the service life of a component or system so, to fix this challenge NDT was introduced.state of art methodology is applied to assess the current condition, fitness for service and remaining life of the equipment. Non Destructive Test inspection provides basic data helping to develop strategic plans for extending plant life.

Non Destructive Test life assessment service include -

Fitness for service evaluation.
Predict fatigue damage
Predict creep damage
Assembly integrity analysis.
Predict corrosion damage.

Non Destructive Test technologies are -

Ultrasonic Test
Thermography Test
Visual inspection
Liquid Penetration
Radiography
Magnetic particle test

1.Ultrasonic Test:

Ultrasonic Test is used to find the defect and the discontinuity when the component is made up of ferrous and non-ferrous material. in this test, transmission of a high-frequency sound wave into a material to detect the discontinuity and to locate the change in the material properties.. any internal discontinuity interrupts the beam and reflects back to a portion of the sound energy. the amplitude of the reflected energy and the time required for return, indicate the presence and the location of the defect in the components.

Advantages

Capable of being automated.
Instant test result.
Access to only one side necessary.
It is not hazardous.

Disadvantage

Rough material, an irregular shape is difficult to inspect.
It requires a highly skilled and experienced operator.

2.Thermography Test

Thermography Test is used to obtain the thermal image of the components in order to detect surface or sub-surface defect in the components. this test is based on the fact that the internal structure of the test components and its flaws will have a different thermal behaviour.when the thermal wave reaches to the defect then the rate of propagation changes.

Advantages

It shows a visual picture
Able to find deteriorating.
Not require skilled monitoring.

Disadvantages

Cost of the instrument is relatively high.
Difficult to interpret

3.Visual inspection

It is one of the basic inspection methods for many applications. This inspection involves using an inspectors eyes to look for defects. It is the first step in the examination process to inspect the product including, forging, casting, and machined products

Advantages

Economical
Gives fast result
Portability

Disadvantages

should have good eyesight
Suitable for visible surface
Not suitable for small defects

4.Liquid penetration

This method is suitable for the components which are made up of ferrous and non-ferrous material.

A cloured liquid is applied on the surface of the body is allowed to penetrate into the flaw by capillary action and low surface tension. The developer acts like a blotter and draws the penetrant out of the flaw. the components are inspected under ultraviolet light to reveal the presence of the defect.

Advantages

the very small discontinuity can be detected
suitable for complex shape also
portable
low cost

Disadvantages

Only surface breaking detect
post cleaning is required
Multiple process operation must be performed

5.Radiography

In this method, either X-ray or Gamma ray is used to inspect the body. Radiation is directed through a part and then onto a film. finally, the inspection result shows in the dimensional features of the part.

Advantages

Applicable for all the material
permanent record of inspection.
Assemblies can also be inspected

Disadvantages

Expensive
High-intensity radiation
slow result

6.Magnetic particle test

This inspection method is used to the body which is made up of the ferromagnetic material such as steel and iron. the test body is magnetised by inducing an electric current into it. In case of any defect, the magnetic field lines get interrupted creating magnetic poles of attraction.

Advantages

Economical
portable
Excellent for very shallow and fine surface cracks

Disadvantages

Difficult to find out the internal defect
post demagnetization is require
chances to burnt the material during magnetization.

Design of Pattern, Mould and Core.

2018-08-19T01:00:00.000+05:30

1.DESIGN OF PATTERN:

1.1. What Is Pattern?

Ø Pattern is basically mould forming tool in the hands of foundrymen.

Ø Pattern is also defined as a model or replica of the object to be cast, but it only looks like a casting object. It has different shapes than the object to be cast.

Ø These extra dimensions of the pattern than the casting product are known as ‘Pattern Allowances.

NPTEL

1.2. Steps In Designing Of Pattern:

The steps in designing of the pattern are given as follows:

[A]. Selection of Pattern Material

[B]. Determining Pattern Allowances

[C]. Determining Pattern Type to Be Used For Particular

Application.

We will discuss these steps in brief.

[A].Selection Of Pattern Material:

Ø The common materials of which the patterns are made are as follows: Wood,Metal,Plastic,Plaster,Wax

Ø Wood patterns are commonly used because they are cheap and easily available in large quantities.

Ø But wood patterns are weak & they absorb the moisture hence they get warped.

Ø Wooden patterns are used where the number of casting to be made is less and the size of the pattern is large.

Ø Metal patterns are cast from wooden patterns.

Ø Metal patterns are used when a large number of castings has to be produced from the same pattern.

Ø Plastic patterns are used because of their low weight, high strength & less costliness.

Ø Plaster patterns are used for making small and intricate patterns.

Ø Wax patterns are exclusively used in the investment casting process.

[B].Determining Pattern Allowances:

Ø Pattern is always made larger than the final casting because it carries certain allowances due to metallurgical and mechanical reasons.

Ø Allowances provided on the pattern:

1. Shrinkage allowance

2. Machining allowance

3. Draft and taper allowance

4. Distortion allowance

5. Rapping allowance

Ø All the metals used In casting work shrink or contract during cooling, to compensate contraction adequate allowances are provided on the pattern.

Ø Machining allowance is the amount of dimension on a casting which is made oversized to provide stock for machining.

Ø Draft allowance is given for easy removal of the pattern from sand.

Ø The casting can distort sometimes, so to eliminate the distortion problem opposite distortion is provided on the pattern is known as distortion allowance.

Ø While taking out the pattern mould is rapped and shaken to make pattern free from adjoining sand, so there is little increase in mould size. So to compensate for this problem negative allowance i.e. rapping allowance is provided.

[C].Determining Pattern Type to Be Used For Particular Application:

1. Single piece or solid pattern: e.g. stuffing box of steam engine

2. Split pattern: e.g. casting of taps & water stopcocks

3. Loose piece pattern: e.g. fixed in the moulding sand

4. Cope & drag pattern: e.g. used for producing the large casting

5. Gated pattern: e.g. used for producing the small casting

6. Match plate pattern: e.g. piston rings of IC engine

7. Sweep pattern: e.g. large kettles of cast iron

8. Skeleton pattern: e.g. turbine casting, water pipes, L-Bends

9. Segmental pattern: e.g. used for producing large circular castings

10. Follow board pattern: e.g. casting master patterns

11. Lagged up pattern: e.g. casting of the cylindrical workpiece

MOULD DESIGN:

When the pattern is made sand is packed around it. When the pattern is removed from this sand cavity looking like the pattern is formed in the sand. This cavity is known as mould or mould cavity. In other words, the mould is the container which when poured with molten metal produces the casting of the mould shape.

Designing of the mould depends upon selecting mould material according to the application, selection of gating system, selection of runner system, selection of the de-gating system, a venting system for hot gases producing in the system. Mostly refractory sand is used as the mould material.

CORE DESIGN:

A core is a sand shape or form which makes the contour of casting for which no provision is not made in the pattern for moulding. Core is made up of sand, plaster, metal or ceramics. The core is used to produce hollow castings, shapes which are difficult to produce by simple moulding.

Essential parameters in core design are,

Diameter of the core
Core aspect ratio
Inter-core distance

DIAMETER OF THE CORE:

In most of the castings, low diameter holes can’t be produced by using cores. The main reason is thick sections of the castings try to fuse with small core material i.e. sand, metals. And then core can’t be separated from casting easily. So the minimum recommended core depends on the metal which to be cast, the casting process, the thickness of the section in which the hole is located, and the length of the core.

CORE ASPECT RATIO:

Aspect ratio means the ratio of the length of the core to a diameter of the core. If this ratio is increased then the core is said as Narrow Core. And if the aspect ratio of the core is large, metal cores can distort & sand cores can break under pressure. So the aspect ratio of the core should be selected within the limits.

INTER-CORE DISTANCE:

This parameter covers the point of limiting the centre distance between two adjacent cores. When two cores are placed very closely then it leads to a thin section between two holes. Because of that, the poured metal can’t occupy these thin sections completely. The heat transmission in the small section will be less due to less area for heat transfer. Because of less heat transfer in between two cores leads to shrinkage porosity in this small section due to this section will be porous an weaker. So to avoid these problems distance between the cores is kept greater than the core diameter.

How Hydraulic Brakes work.

2018-08-16T01:19:00.000+05:30

Hydraulic Brakes
Hydraulic brake system transmit the force pedal to each wheel brakes through the pressurized fluid.when the force is applied on the brake it converts the fluid pressure into the useful work to stop or reduce the speed of the vehicle.The brake fluid is in compressible and it exert equal pressure in all the direction.
Hydraulic brakes based on the principle that " when the pressure is exerted on a confined liquid , it transmits pressure without loss, equally in all direction". when the driver applied the brake, it exert a force on the the piston of the master cylinder then this force is transmitted to the wheel. Each wheel is having the piston wheel cylinder arrangement, piston in the wheel cylinder transfer the force to the brake shoe. when the brake is not applied ,50 to 55 kpa is maintained in the steel piping to keep the wheel cylinder piston in the expanded position.

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components of hydraulic cylinder are:-

brake pipe
brake shoe
master cylinder
brake drum
brake pedal
wheel cylinder

1.Brake pipe

usually the brake pipes are the steel pipe, when the force is applied on the brake pedal, hydraulic pressure is generated in the master cylinder .This pressure is equally transmitted through pipe to wheel cylinder.

2. Brake shoe

It create the friction in the drum which is necessary to stop and reduce the speed of vehicle.Friction between lining and drum provide the braking effort.

3. Master Cylinder

master cylinder is filled with the fluid, when the force is applied on the pedal it converts the non-hydraulic into the hydraulic pressure.

4.Brake drum

It uses the friction produce by the brake shoe and oppose the movement of the rotating cylinder .

5.Brake pedal

It exert the force which applied by the driver against the brake disc which slow the wheel down.

6. wheel cylinder

it exert the force on to the shoe as to bring them into contact with the drum and stop the vehicle.

Advantages

Equal braking action on the wheel.
increase braking force.
simple in construction.
low wear rate of braking linings
Does not generate sparks.
high horse power to weight ratio.
Multiplication of force

How Electronic Ignition System works.

2018-07-21T22:50:00.005+05:30

Electronic Ignition System is a advance ignition system, it produces higher voltage than the conventional ignition system.this system generate much stronger sparks which is needed to spark the lean mixture . conventional ignition system produces 10-15 kv to ignite the mixture. But now a days the scenario has been changed,modern high speed engine needed 15-30 kv to ignite the mixture .

In this system the transistor play very important role. A transistor has ability to switch large amount of current without the use of moving parts.The transistor make use of semi conductor and the most common material used for semi conductor is germanium (antimony material added) because its border line acts as good insulator.

Usually PNP transistor is used in the automotive ignition system.If the transistor is consist of 2 section of "P"and one section"N", then it is called PNP transistor.

AutoExpose

The basic parts of transistor are , Base,Emitter and Collector,denoted by B,E and C respectively.

The electronic ignition system have two circuit, primary circuit and secondary circuit , secondary circuit is same as that of the conventional ignition system.

Electric source is supplied to the E-B circuit and E-C circuit. The base current is only a fraction of the collector current, but the collector current can not exist without the base current.if the current flow in the base circuit is interrupted , causes disturbance of large current flow in the collector circuit.

Chevythunder

The collector is connected to primary winding in the ignition coil and the emitter is grounded. when the cam operates,the primary circuit current is disturbed , thereby induces high voltage in the secondary voltage that is used to ignite the lean mixture at the right time in combustion chamber.

Advantages

System can work with or without condenser.
smooth engine operation.
More horse power.
There is no wear on contact set and no points bounce.
Reduce power loss and fuel consumption.
Contact points carry small amount of current compare to conventional ignition system.

Disadvantages

Require regular adjustment to compensate wear.

Also Read How Magneto Ignition System works

Ignition System and Battery Ignition System

How Magneto Ignition System works

2018-07-18T19:43:00.000+05:30

Ignition system is a group of components which deliver the spark to the spark plug to ignite the air fuel mixture.

Mainly we have three types of ignition system:-

Battery Ignition System
Magneto Ignition System
Electronic Ignition system

2. Magneto Ignition System

Name of the ignition system itself indicate that in this system magnet is used . when magnet is run by the engine it produces current and supplies to the primary winding .system having set of winding namely primary winding and secondary winding.Battery and ignition coil of the battery have been replaced by the compact magneto. low current voltage is converted into high current voltage by disturbing the path of the current which is enough to spark and fire the air fuel mixture.
Components of Magneto Ignition System are- Magneto,breaker points,condenser ,ignition switch, distributor,spark plug

Magneto Ignition system is classified into two types :-

Rotating Armature Types

Rotating armature is consist of two coils, one is primary coil,one secondary coil and condenser. primary coil having few hundred winding of wire where as secondary coil having some few thousand turns winding of wire .Contact breaker and condenser is attached to the armature which rotates between the pole of permanent magnet .

me-mechanicalengineering.com

when the armature rotates in between the magneto ,magnetic flux in the core reaches zero to maximum.
As the magnetic flux alternatively increase and decrease, the voltage is induced in the primary coil and secondary coil.
As we can see in the fig. when the breaker points are closed ,current flow in the primary circuit. breaker points are actuated by the cam which is attached to the rotor of the follower.
By means of the breaker points ,an increase in the rate of the magnetic flux break down is produced
Rapid discharge of the condenser produce an instantaneous break down of the magnetic flux .
A rapid break down induces very high voltage 10k to 20k volts in the secondary circuit
This high voltage is distributed by distributor to spark plug according to the firing order of the engine and hence spark plug ignite the mixture in the combustion chamber.
Engine can be stopped by closing the ignition switch and grounding the primary circuit.

2.Rotating Magneto Type

working principle of this system same as that of the rotating armature system.Here the magnet itself rotate to produce the require current to produce the spark.

Aircraft systems - Blogger

Also read Ignition System and Battery Ignition System

Need of Lubrication System in Engine and its Function.

Ignition System and Battery Ignition System

2018-07-17T17:03:00.000+05:30

When the air fuel mixture introduce to the I.C. engine it expand in the cylinder as the piston move from top dead center(TDC) to bottom dead center(BDC). operation of the I.C engine depend upon the burning and expansion of the air fuel mixture within the cylinder.Ignition system is used to ignite the air fuel mixture for complete combustion of the fuel.Ignition of the must be occur at the right time to produce the maximum energy during the expansion of hot gases in combustion chamber.

Ignition system is a group of component which delivers the sparks to the sparks plug at the right time to fire the air fuel mixture.

In 2 stroke engine , spark plug produces spark in cylinder for every revolution of the piston.
In 4 stroke engine, spark plug produces spark in cylinder for every alternate revolution of the piston.

Ignition system transfer low voltage to high voltage and this voltage is used to proper spark at the right tome.

Now a days Lean mixture are used in the vehicle to reduce the pollution level in the environment.

lean mixture is a mixture of air fuel having the air ratio is more than the fuel.such mixture require higher voltage ignition system to ignite the mixture.

Types of ignition system

Point ignition system:- Breaker points are used to interrupt the primary current in circuit.

E.g- Battery ignition system, magneto ignition system

2.solid state ignition system: This system is used in any engine which uses electronic device like diode. in this system primary current stopped and restarted.

Battery Ignition System

Most of the I.C engines uses battery ignition system. in this system a 12 volt battery supplies the electric current to the coil and the ignition coil is an electrical transformer which changes low voltage to high voltage current which produces enough current at the right time to fire the mixture.two coils are used in this system ,primary coil and ignition coil . Ignition coil is consist of two winding , primary winding of 150 to 200 turns and the secondary winding of 10000 to 20,000 turns. This helps to transform the low voltage current to high voltage current.

Primary circuit completed when the contact points are closed and primary current flow through the primary winding. This current induced the EMF in the secondary coil.when the breaker break yhe path of the current flow and it produces high voltage.Hence the ignition coil store the energy in the form of magnetic field and deliver to spark plug at the right time whenever it is require .

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Advantages

There is no moving part.
Produces better sparks at low speed of the engine.
Distributor set is simple
Cost is less

Disadvantage

If battery exhausted , engine will not start
when the speed of engine increases , sparking voltages gets decreases.

Need of Lubrication System in Engine and its Function.

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Lubrication System

The engine is made of many moving parts and these parts are in continuously moving condition. when the two or more parts meet then there is friction and wearing take place, generation of heat and the loss of power in the engine. Hence the lubrication system is necessary to prevent the engine from these harmful effects.

The system which is used to introduce the lubricant to the engine is called the lubrication system.

lubrication system introduced the oil and other lubricants to give a flow to the clean oil at the desired temperature with an appropriate pressure to the moving parts for the smooth function of the moving parts to avoid the harmful effects.

Mainly these losses take place-

Direct frictional losses
Pumping losses
Losses due to driving components

The function of the Lubrication system

Reducing frictional effect
cooling effect
sealing effect
cleaning effect

lubrication

1. Reducing frictional effects:

when the two moving parts meet rubbing take place and high amount of heat generated. two rubbing surface always produce friction and this friction leads to wear.friction between two parts directly affect the performance of the engine so it must be reduced as far as possible for the smooth function of the engine. this problem can eliminate the proper distribution of the lubricant on the moving parts.

2.Cooling effect:

When the moving parts move like the piston inside the cylinder, piston comes in touch with the cylinder and rubbing take place, parts get heated up.Hence the lubrication is used to cool the engine parts.

3.Sealing effect

as the term itself define the function, there is some gap is found between the parts then there is the possibility of gas leakage from the engine. The gap between the cylinder, and liner, piston and piston ring etc. Hence the cooling system prevents the leakage.

4. Cleaning effect

when the engine is in moving condition, foreign dust particle gets deposited on the surface of the moving parts which can affect the performance of the engine. proper cooling takes away these unwanted particles from the surface.

Engine position in the vehicles.

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Engine is the heaviest component of the vehicle, and its position directly affect how the car drives. Engine can be placed on chassis in the three different position.
1. Front position engine
2. Rear position engine
3. under floor position engine
1.Front position engine
In the front position engine , engine is placed at the front of the engine and rear wheel drive are used. but in some of the vehicle drive is given to the front wheel only.The engine placement is remains the same in the heavy vehicle, but the cab is brought forward over the the engine to increase the pay load. The engine position at the front with rear wheel drive system require greater length of the shaft.

Autoxpat

This engine position gives the protection to the driver when the head collision happen as the mass of the engine is greater than the any other parts of the vehicle .
In case of rear wheel drive

The weight distribution is reasonably balanced between the front wheel and rear wheel which gives good handling support.
Due to engine and radiator are at front the forward facing radiator take full benefits of the natural air flowing produce by the vehicle movement.

2. Rear position engine
In this position, the engine is mounted to close to the back axle. The propeller shaft require is reduced and usually it is used for small car.This position provides more space to the passenger cabin.
The major portion of the vehicle lies on the rear wheel and it help to in traction
up the hill. luggage is kept at the front near to the driver which some how balance the vehicle.

mindovermotor.com

3.under floor position engine
This position of the engine is also called as Mid position engine. in this the engine is in the center, under the chassis .basically this system is used in the public service vehicle like bus and the heavy lorry. it reduce the crankshaft length from the engine to axle. special features of this system that it eliminate the heat and noise from from the vehicle, to fix the engine problem and maintenance is easy.

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Internal Combustion Engine Parts and its Function.

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Internal combustion engine is a very complex , it is consist of huge number of parts. so it would be bit difficult to explain each part .
Important parts of the internal combustion engine.

http://www.machinedesign.com/motorsdrives/difference-between-car-engines

1.Cylinder

They cylinder is the main body of an engine in which piston reciprocates to develop power.
It has to with stand high pressure and temperature around 2900 degree Celsius.
Cylinder block in which houses the engine cylinders.
Engine material should be good conductor of heat and should resist wear and tear due to reciprocating.

Material:- Generally cast iron is used - for heavy duty engine alloy steel are used

2.Cylinder liners

It is used to reduce the wear and increase the cylinder life.
If the cylinder is made up of aluminium alloy then the wear of the cylinder is more.
Whenever cylinder block is inserted beyond the allotted space then the liner bring it to it's original position.
Types of liner

Dry liner
Wet liner

Material:- alloy iron*

3.Piston

Piston is a reciprocating part of the engine and convert the combustion pressure to force on the crankshaft.
It has enough strength to withstand the high pressure.
It's construction is rigid to withstand thermal and the mechanical distortion.
Piston diameter is smaller than the cylinder bore.
It has the shape of an inverted bucket,the top portion is called crown or head.

Material:- aluminium alloys

4.Piston rings

Piston rings are located on the top of the piston, and it is used to maintain the seal between the piston and the cylinder bore.
It is made up of grey cast iron or alloy cast iron because of its good wearing properties even at the high temperature.
It provide passage of heat flow from the piston head to the cylinder wall.
It maintain the lubricating oil in the cylinder wall throughout the movement of piston that reduces the wear between the ring and cylinder wall.
Types of piston ring

compression ring
oil ring

Material:-fine grained alloy cast iron

5.piston pin

It is used to connect the piston and the connecting rod, it is also called as the wrist ring.
It is in tabular shape to provide adequate strength with minimum weight.
The center of piston pin usually be 0.02D to 0.04D above the center of the skirt.
The piston pin is fastened to the connecting rod by means of bolt and uses the piston bosses for bearing

Material:- low carbon case hardened steel.

6.connecting rod

The connecting rod are used to connect the piston to the crankshaft.
It converts reciprocating motion of the piston into rotary motion of the crankshaft.
The upper end of the rod oscillates while the lower end is rotates.
The rod has an I - beam cross section to provide maximum rigidity with minimum weight.

Material:- malleable cast iron

7.Crank shaft

It is used to covert the reciprocating motion of the piston into the rotary motion.
Crankshaft receive the power from the connecting rod and at the same time transfer to the wheels.
The crankshaft is held in position by a number of main bearing and they form for the rotation of the crankshaft.

material:-alloy steel or cast iron

8.valves

Valve is a device that regulates or control the flow of fluid and gases.
Each engine cylinder has two valve called inlet valve and exhaust valve.
Air-fuel mixture is introduced through the inlet valve and the burn gases escape out from the exhaust valve .
The inlet and exhaust valve are made up of different material as they are subjected to different operation condition.
Types of valves

Poppet valve
Sleeve valve
Rotary valve

Material:- silicon-chrome steel

Classification of Internal Combustion Engine

Two Stroke engine and its function.

Four stroke engine, Difference Between Four Stroke and twoStroke Engine.

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