| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.55 |
| Score | 0% | 71% |
An overcooled engine:
generates more power |
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is less efficient |
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uses less gasoline |
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is more efficient |
An overcooled engine is less efficient. During the power stroke, combustion heat pushes down the piston. If too much of this heat is lost to the cooling system, the fuel might not combust completely and contaminate the engine's lubricating oil diminishing its lubricating ability. Incomplete combustion of fuel also negatively affects the engine's fuel efficiency and power output.
Both intake and exhaust valves are closed as the piston begins moving back up from the bottom of the cylinder, compressing the air-fuel mixture in the combustion chamber which also makes it hotter. This describes which engine stroke?
compression |
|
power |
|
exhaust |
|
intake |
During the compression stroke, both intake and exhaust valves are closed as the piston begins moving back up from the bottom of the cylinder (bottom dead center or BDC). This compresses the air-fuel mixture in the combustion chamber which also makes it hotter.
Engines with radial cylinder configurations are most common in:
aircraft engines |
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heavy truck engines |
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tank engines |
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train engines |
A radial arrangement places cylinders in a circle around the crankshaft and is used almost exclusively in aircraft engines.
When a car engine is running, what provides electrical current to recharge the battery and power the electrical system?
alternator |
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solenoid |
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battery |
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camshaft |
Once the engine is running, the alternator provides electrical current to recharge the battery and power the electrical system. The alternator is driven by the engine's crankshaft and produces alternating current (AC) which is then fed through a rectifier bridge to convert it to the direct current (DC) required by the electrical system. A voltage regulator controls the output of the alternator to maintain a consistent voltage (approx. 14.5 volts) in the electrical system regardless of load.
The piston moves downward in the cylinder creating a vacuum that pulls an air-fuel mix into the combustion chamber. This describes which engine stroke?
intake |
|
compression |
|
exhaust |
|
power |
The four-stroke piston cycle of internal combustion engines starts with the piston at top of the cylinder head (top dead center or TDC) during the intake stroke. The piston moves downward in the cylinder creating a vacuum that pulls an air-fuel mix into the combustion chamber through the now open intake valve.