Common Car Repairman Interview Preparation Guide

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Low emissions. Essentially no CO or HC in the exhaust as there is no carbon in the fuel. Most exhaust would be H2O and N2 Fuel availability. There are a number of different ways of making hydrogen, including electrolysis of water.

Back compression means the compression capability of the engine. An diesel engine can compress at the ratio of 14:1 to as high as 25:1. Thus the higher compression leads to better efficiency of the engine. Thick black smoke is emitted when the engine’s compression is reduced which leads to the deformed ead-gasket lead into crankcase.

Octane number can be defined as the percentage, by volume, of iso-octane in the mixture of iso-octane and h-heptane. It is the measure of rating of SI engine.

While cetane number can be defined as the percentage,by volume, of n-cetane in the mixture of n-cetane and alpha methyl naphthalene. It is the measure of rating of CI engine.

This will result in damaging of the engine faster. Adding oil will lead to the higher wear and tear of the cylinder liner, piston and damage to the piston. It will lead to abnormal combustion and knocking and detonation. Dark smoke and abnormal sounds will be generated by the engine. One should not mix oil with the fuel of four stroke engine.

Pitching is a rocking action about a transverse axis through the vehicle, parallel to the ground. The front suspension moves out of phase with the rear, experiencing the rocking effect due to pitching.

When the engine is too cold the thermostat closes the main valve, thus stopping the flow to the radiator. When the engine is too hot, it opens the main valve for normal circulation through the radiator.

BHP is ‘Brake Horsepower’. It reflects the powerfulness of the brakes of the vehicles. BHP stands for how much power will be required to make the engine stop working i.e. to stop the rotation of the engine.

BHP = 2 times pi times torque times revolutions; all this divided by 550. Pi is 3.1416 and torque is in pounds-feet, and revolutions are revs per second.

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

In the case of the engines powered by diesel fuel supply systems, unit pump & unit injector are operated by camshaft & thus pressure of injected fuel depends on engine speed. Whereas,in common rail systems it is independent of engine speed.

The property of a fuel, which describes how fuel will or will not self-ignite, is called the octane number or just octane. Engines with low compression ratios can use fuels with lower octane number, but high compression engines must use high-octane fuels to avoid self-ignition and knock.

This system is based on Pascal’s law. In a tractor the pressure is same, so the force given by the liquid to the surrounding is equal to the pressure X area. Thus, obeying the Pascal’s law hydrostatic propulsion system is designed, similarly small piston feels small force and the large piston feels larger area.

When the clutch is not disengaging fully and provides some difficulty in changing the gears then this defect is called clutch drag.

Adding gasoline to the diesel engine may blast off the engine. Compression ratio of the petrol engine is 6 to 10 and diesel engine is 15 to 22. Thus gasoline will get very highly compressed and might result in blast off engine.

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

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

Air conditioners are based on the principles of evaporation and condensation and then compression and expansion. The hot air of the car is removed by the process of evaporation and then the condensation of the evaporated air takes places which is then further compressed by the compressor and then finally expanded to us in the form of cold breeze. Somehow, Air conditioning reduces the average of the car, as the energy is required to remove the hot air and then compression and expansion.

a. Viscous friction

c. Decreased

c. 30 m kg of work

c. I – head

b. Intermediate speed

b. 20:1

a. High speed jets

If you haven't worked on automobiles in a professional setting, don't sweat it! You can include your experience working on your own cars or others. When you respond to this question, you want to go in depth about the type of work you have done, sharing your knowledge and areas of expertise. Rather than saying, "I have about 8 years of experience,"

The two stroke engines have very high range to be compared to the four stroke engines. Because power stroke is generated every two revolution while in four stroke, power stroke is generated every four revolutions.

SAE stands for society of automotive engineers. This society is responsible for developing the standards for the engineering of powered vehicles of all kind. The vehicles may include car, boat, truck and even aircraft. SAE has developed standards for ground vehicles and aerospace vehicles. SAE also encourages students of engineering, technology, science and math’s disciplines. This society has been publishing technical information since 1906.