ASVAB Automotive Information Practice Test 396344 Results

Your Results Global Average
Questions 5 5
Correct 0 2.83
Score 0% 57%

Review

1

Which of the following is not a function of antifreeze?

54% Answer Correctly

keeps water from freezing at low temperatures

lubricates the cooling system

raises the boiling point of water

aids heat transfer


Solution

Modern car engines are cooled by liquid which circulates through the engine block and cylinder heads absorbing excess heat. This liquid is made up of half water and half antifreeze (commonly, ethylene glycol) which both keeps the water from freezing at low temperatures and raises its boiling point making heat transfer more efficient.


2

What is the name of the proper ratio of air to fuel necessary so that an engine burns all fuel with no excess air?

62% Answer Correctly

combustion ratio

ignition ratio

stoichiometric ratio

residual ratio


Solution

The stoichiometric ratio defines the proper ratio of air to fuel necessary so that an engine burns all fuel with no excess air. For gasoline fuel, the stoichiometric ratio is about 14.7:1 or for every one gram of fuel, 14.7 grams of air are required. Too much air results in a lean air-fuel mixture that burns more slowly and hotter while too much fuel results in a rich mixture that burns quicker and cooler.


3

Ignition timing defines the point in time at the end of the compression stroke that which of the following happens?

69% Answer Correctly

intake valve opens

the air-fuel mixture enters

exhaust valve opens

spark plugs fire


Solution

Ignition timing defines the point in time at the end of the compression stroke that the spark plug fires. Measured in number of degrees before top dead center (BTDC), the exact point that the spark plugs initiate combustion varies depending on the speed of the engine. The timing is advanced (the spark plugs fire a few more degrees BTDC) when the engine is running faster and retarded when it's running slower.


4

Just before the piston reaches top dead center, the spark plug fires and ignites the compressed air-fuel mixture. This describes which engine stroke?

61% Answer Correctly

compression

power

exhaust

intake


Solution

During the power stroke, just before the piston reaches top dead center, the spark plug fires and ignites the compressed air-fuel mixture. The resulting expansion due to combustion pushes the piston back down the cylinder toward bottom dead center.


5

Which of the following is not a part of the oil pump?

38% Answer Correctly

pressure relief valve

oil filter

oil galleries

all of these are part of the oil pump


Solution

The oil pump is driven by the camshaft and is responsible for pumping oil through the oil galleries (passages) that run throughout the engine. It also contains the oil filter and a pressure relief valve which prevents excessive pressure from building up in the lubrication system.