| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.21 |
| Score | 0% | 64% |
Too much fuel results in a __________ air-fuel mixture that burns quicker and cooler.
heavy |
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lean |
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light |
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rich |
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.
A vehicle's lighting system is protected from current spikes by:
the voltage regulator |
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the alternator |
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the battery |
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fuses and circuit breakers |
The lighting system consists of interior lights, instrument panel lighting, headlights, and taillights. Like household electrical circuits, the vehicle's lighting system is protected from current spikes by fuses and circuit breakers.
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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synchronous |
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retarded |
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asynchronous |
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.
Which of the following is not an advantage that disc brakes have over drum brakes?
provide more braking force |
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are more easily cooled |
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use less brake fluid |
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provide a larger contact area |
Brakes utlize friction to slow vehicle tires. Drum brakes employ a cast iron drum that roates with the vehicle axle. When hydraulic pressure is applied to the brake assemblies at the wheels, internal pistons expand and push brake shoes outward into contact with the brake drum slowing the rotation of the axle. More powerful disc brakes operate by pinching a rotating disc betweeen two brake pads and allow for a larger surface area to contact the disc, provide more force, and are more easily cooled.
What is the function of the head gasket?
to connect the transmission to the drive train |
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to seal the engine block from the cylinders |
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to seal the exhaust system from the drive train |
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to seal the brake assembly from external contaminants |
A head gasket is a gasket that sits between the engine block and cylinder heads to seal the cylinders to ensure maximum compression and avoid leakage of coolant or engine oil into the cylinders.