| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.93 |
| Score | 0% | 59% |
Another name for the powertrain control module is the __________ control unit.
electrical |
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engine |
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universal |
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transmission |
The main computer or powertrain control module (PCM) uses pre-programmed software to analyze the input received from sensors and produce output signals to adjust vehicle performance and operation. (Engine control unit (ECU) is another name for the PCM.)
Which of the following is not a characteristic of disc brakes?
uses a rotor |
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newer brake system |
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uses brake shoes |
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uses brake pads |
Both drum brake and disc brake assemblies use friction to stop a car's wheels from turning but each do it in a slightly different way. A drum brake assembly uses a large iron drum attached to the wheel and brake shoes that press against the drum to slow the rotation of the drum and, consequently, the wheel. A disc brake assembly employs friction in the same way as a drum brake but instead uses a rotor, also attached to the wheel, and two brake pads that squeeze against the surface of the rotor.
Which of the following is not a function of antifreeze?
aids heat transfer |
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keeps water from freezing at low temperatures |
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lubricates the cooling system |
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raises the boiling point of water |
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.
Which of the following statements about v-type cyllinder arrangement is false?
has an odd number of cylinders |
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common in motorcycles, cars, and trucks |
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engine is shorter than an inline engine |
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has two rows of cylinders |
A v-arrangement has two rows of cylinders in a V-shaped block with a crankshaft at the bottom of the V. Any even number of cylinders is possible in this configuration from the V-2 that's commonly used in motorcycles up to V-12 or bigger for large trucks. The V design produces a shorter engine than an in-line cylinder configuration and allows for better air-fuel distribution.
The spark plugs fire a few extra degrees before top dead center when the engine is running faster. In this case the engine's timing is:
advanced |
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retarded |
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asynchronous |
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synchronous |
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.