| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.93 |
| Score | 0% | 59% |
Which of the following is a common firing order for four-cylinder engines?
1-3-4-2 |
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3-1-2-4 |
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4-3-2-1 |
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1-2-3-4 |
The stroke cycle of an engine is governed by the crankshaft which serves to regulate the firing order of the cylinders. All cylinders are not on the same stroke at the same time and correct firing order is important to balance engine operation and minimize vibrations. A common firing order for four-cylinder engines is 1-3-4-2 which indicates that cylinders 1 and 3 fire (power stroke)together and cylinders 4 and 2 fire together.
The right front wheel of your front-wheel drive car drops into a pothole and the left front wheel doesn't lose contact with the road. Which of the following is true?
your car has a rigid axle rear suspension |
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your car has an independent front suspension |
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your car has an independent rear suspension |
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your car has a rigid axle front suspension |
An independent suspension allows the wheels on either side of an axle to move independently from each other. The fact that the left front wheel didn't move up in response to the right front wheel moving down is evidence of this.
What is the primary difference between internal and external combustion engines?
how the fuel is ignited |
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where the power is developed |
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the air-fuel mix for optimum combustion |
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the type of fuel used |
The primary difference between internal and external combustion engines lies in where the power is developed. In an internal combustion engine fuel is ignited and burned inside the same container where the power is developed while in an external combustion engine the fuel is ignited outside the engine and the resulting power sent to it.
Which of the following statements about fuel injection is false?
atomizes fuel using high pressure and injects it into the engine |
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relies on suction to draw fuel into the engine |
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has replaced the carburetor as the primary fuel delivery system used in automotive engines |
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optimizes fuel delivery using various electronic engine sensors |
Fuel injection has replaced the carburetor as the primary automobile fuel delivery system. The main difference between the fuel injector and the carburetor is that fuel injection atomizes the fuel by forcibly pumping it through a small nozzle under high pressure while a carburetor relies on suction to draw fuel into an accelerated intake air stream.
Too much air results in a __________ air-fuel mixture that burns more slowly and hotter.
heavy |
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light |
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rich |
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lean |
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.