Automobile Engineering Interview Questions and Answers

The responsibilities of the automobile engineers are:

• Automobile or automotive engineers are the responsible for the designing, developing, maintenance, production, and the servicing of the vehicles.
• And they are implement the vehicles production and designing of motors with the use of new technologies.
• Automobile engineers also responsible for the internal and external designs, and final design output of vehicle, and comfortable for the passengers.
• These engineers are also responsible for the writing report, maintaining the project, supervising technical teams and deals with the clients.
• And also need the knowledge of electronic, electrical, and IT systems, for developing the new technologies of vehicles.

BS full form is “Bharat stage”. It is a emission standard. The main difference between the BS₂and BS₃ engines is to present in the catalytic converter. In the BS₃ engine the catalytic converter is used to reduced the formation of the HC and CO. And in the BS₂ engines the catalytic converter is does not used for the formation of HC and CO. In the BS₃ engines there is no harmful emissions in the HC and CO.

The emission of these type of BS₂ contains:

Sulphur – 0.5 g/kg.

Lead – 0.013 g/liter.

The emission of these type of BS₃ contains:

Sulphur – 150 mg/kg for gasoline, and 350 mg/kg for diesel.

Lead – 0.005 g/liter.

There are three methods for heat transfer. They are:

Conduction: The heat is transferred by using the solid materials, that is the transfer of energy by collision between the molecules in that material  is called conduction.

Convection: The heat is transferred by the gases, that is the particles moves between the objects or the places that differ in temperatures is called convection.

Radiation: The heat is transferred through the electromagnetic waves that is called radiation.

Big tyres provide a large surface area on the touching the ground because it providing the more pulling power. That why the tractors has the big rear tires. The tractors does no operates the high speed because to get the same ground speed with a larger tyres. Gear ratio does not have to higher than the b/c of large tyres.

BHP means “Brake Horse Power”. BHP reflect the power of the brakes of engine. And it is used to measure the how much of power will be required to stop the engine that is to stopping the rotational of the engine. And these power is measured by using the dynamometer. BHP is measured by the following formula:

BHP = (2π × torque × RPS) / 550. Where π = 3.1416, and torque is measured in pounds-feet, and revolutions are measured in revs per second.

Or it is also measured by using the formula: BHP = (torque × RPM) / 5252.11

Two stroke engines and four stroke engine both have the same components, but don’t work in the same way.

Two stroke engine: In crankshaft, one working stroke in each cylinder per revolution. The moving parts are few with the light weight. Two stroke engine construction is simple and easily maintained. And it causes disturbance with more noise.

Four stroke engine: In crankshaft, one working Stroke in each cylinder per two revolutions. The moving parts are more with the higher weight and larger size. Four stroke engine construction is more complicated due to the mechanism. And it produces less noise.

Octane number: Under standard operational conditions, the percentage of iso-butene present in the mixture of iso-octane and heptane is called octane number. Octane number is the rating of the SI engines.

Cetane number: Cetane is the one of the type of chemical compound called hexadecane. Cetane number is defined as the percentage of the volume of n-hexadecane in the mixture of n-hexadecane and 1-methynaphthalene which is responsible to provide in these delay period. It measured the how quickly the fuel starts burning inside the compression engine.

Octane number and the cetane number both are the standard measures the tendency of fuel to spontaneously. Octane number is to measure the performance of gasoline and the cetane number is used to measure the performance of diesel. The fuel having the high octane number then cetane number is low and the fuel is having the high cetane number then octane number is low. That’s why we cannot use the petrol in A diesel engine and the diesel in petrol engine.

The injection pressure is a pressure at which the fuel is inserted or injected in to the engine of the vehicle. In the heavy vehicles or tractors, the injector pressure is 220 kg/ cm². Injector pressure is used to set up the standard fuel injector in the presented vehicle. And the injector pressure is calculated by using the formula is

Estimated horsepower × B.S.F.C / number of nine times × duty cycle = Ib/hr per injector CC = Ib/hr ×10.5

When we will add the oil to the fuel of four stroke engine it will Faster the damage of the engine. And it effects the higher wear and tear of the cylinder lines, piston. It will damage the piston. Abnormal sounds and dark smoke is generated by the engine due to lead to abnormal combustion and knocking, detonation. So we should not mix the oil with the fuel of four stroke engine.

It indicates the compressive capability of engine. A diesel engine compress at the ratio of 14:1 And does not higher than the 25:1. The higher compressor will used to the better efficiency of the engine. When the engine compressor is reduced due to the deformed ead-gasket lead in to crankcase to emitted the thick black smoke.

Air conditioners are worked based on the principles of evaporation, condensation, and then compression and expansion. Air conditioner are used to remove the hot air by the process of evaporation and then the condensation of the evaporated air takes places and further it is compressed by the compressor and finally expanded to the form of cool breeze. It removes the hot air and then compression and expansion.

The full form of the CC is cubic centimeter. CC of the engine is represented du to the total volume of entire cylinder. The engines with more CC can generate more power than the other engines. CC is inversely proportional to the fuel consumption.

The full form of DTSI is Digital Twin Spark Ignition. In the combustion chamber DTSI is used to get a better combustion. In these techniques to obtain the better combustion of fuel in the cylinder head then double spark plugs are used. In these technique fuel is ignited properly. DTSI provides the better efficiency and economical in the fuel consumption.

 For low emissions. Essentially there is no CO or HC in the exhaust then there is no carbon in the fuel. Mostly H₂O and N₂ are available in the fuel. There are the number of different ways to the making of hydrogen, including the electrolysis of water.

It is used for High octane number it gives the very good S.I engine fuel. The uses of the natural gas in automobiles are low engine emissions, less aldehydes then with methanol.

It refers to the mounting of the wheel on a separate axle, so that the road shocks affect only in the particular wheel.

When the clutch is not disengaging fully and it provides some difficulty in Changing their gears then these defect is called clutch drag.

Two piston crankshaft is a piston that is made up of two materials. Usually skirt is made up of steel and the piston bosses are made up of aluminum.

This mainly depending upon the loading conditions of the generator. Running the generator in no load or low load it consumes low fuel. And in the more load will consume more fuel. In approximately opinion for 500 KVA It Would be around 100 liters per hour.

The hydrostatic propulsion system is works based on the principle of the Pascal’s law. In tractors the pressure is same, so the force given by the liquid to the surrounding is equal to the multiplication of pressure and area. These obtained the Pascal’s law hydrostatic system is designed, and Equally small piston feels the small force and the Massive or large piston feels The large or massive force.

The kingpin offset is the part, basically it is called as pivot. Pivot is used in the steering of the vehicles. This is helps in rotating of the steering and it’s very useful in steering mechanism of the cars.

Applications of kingpin offset: kingpin offset is also used to measure scrub radius with the help of geometric parameters of the wheel plane above and the below the ground level. Offset provides the directional stability to the vehicles when it combined with the caster.

1640 is the rating used for the trucks and the trailers. It means 16 ton and 400 horsepower. This is like to write 1640 became 16400 by adding on zero to the end point and then we segregate 16/400 that is 16 ton and 400 HP.

In case of the drive torque is applied to the rear wheels, this limiting accelerator due to front of the wheel drive due to the transfer of weight. And this drive is also bolted to the chassis of the car. In modern technologies of manufactures to design the rear wheel drive to have the similar handling to the front of the wheel drive it ever possible to the suspension tuning.

Cfm is generally used in spray painting very small areas. Cfm can be used where painting with brush is very difficult. To improve the rate of painting the spray painting is used. These spray painting method is very fast and efficient. Depending on the size of requirement usually reciprocating compressors are used.

Due to the non-conducting nature of plastic this is widely used in the electricity purposes because the plastic is a cheap and strong so it is no cause to the damage. And also the plastic does not ben, and does not slips form the hands of the users.

Governor is the one of the main important component of the automobile engine. Governor is used to regulate the main speed the engine during the loads of the variations. Fuel supply has to be maintained with the variations of loads. This over all task is maintained by the governor. In case of high load on the engine. Speed decreases, fuel supply has to be increased. Similarly, when load decreases then automatically fuel has to be decreased.

The full form of MPFI is Multi Point Fuel Injection. In this system fuel is injected into the intake ports which is situated just upstream of each cylinder’s intake valve. These systems are the sequential systems, in which the injection is timed to coincide with the intake stroke of each cylinder.

The full form of TPFC transient power fuel control system. In this type of systems constant choke carburetor is used. The salient features of these carburetor is that provides the jerk less engine raise. In these systems, throttle valve creates the vacuum which opens the slide which controls the air fuel ratio through a tapered jet.

The full form of SAE is Society of Automotive Engineers. It is the responsibility of the society to the developing the standards for engineering of powered vehicles of all kind. The vehicles may include the trucks, boat, aircraft and cars. SAE is used to developing the front vehicles and the aerospace vehicles. These society is developed and publishing the technical information in the year of 1906.

Pressure cap is a seal in the radiator. It maintains the cooling system when the engine is hot at the selected pressure.

It is a tube or the bar running from the one side of the axle to the frame on the other side of the vehicle. The pan hard rod is used to help the leaf spring in keeping the axle centers under the body during the corner of the turning.