| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.09 |
| Score | 0% | 62% |
Which of the following is the result of the air-fuel mixture exploding instead of burning?
post-ignition |
|
pre-ignition |
|
pre-detonation |
|
detonation |
Normal combustion in an engine is initiated by a spark plug and results in the complete burning of the air-fuel mixture. If combustion is initiated by a source other than the spark plug, by a hot spot in the cylinder or combustion chamber for example, pre-ignition results. Detonation results if the air-fuel mixture explodes instead of burning. Detonation can cause extremes in pressure in the combustion chamber leading to engine damage.
Engines with radial cylinder configurations are most common in:
tank engines |
|
train engines |
|
aircraft engines |
|
heavy truck engines |
A radial arrangement places cylinders in a circle around the crankshaft and is used almost exclusively in aircraft engines.
The fuel injectors are fed fuel by the:
electric fuel pump |
|
powertrain control module |
|
fuel pressure regulator |
|
fuel return line |
The electric fuel pump feeds pressurized fuel through a fuel filter to the fuel injectors via the fuel rail manifold. The fuel rail contains the fuel pressure regulator which ensures that the fuel injectors receive fuel at a consistent and known rate. Excess fuel bled off by the pressure regulator returns to the fuel tank through the fuel return line.
Control arms connect a vehicle's suspension to the frame. The connection to the wheels is through:
bushings |
|
ball joints |
|
pins |
|
knuckles |
Control arms (upper and lower) connect a vehicle's suspension to the frame. The connection to the wheels is through ball joints which allow the control arms to turn and move up and down simultaneously. The frame connection uses bushings.
Which of the following is not an advantage that disc brakes have over drum brakes?
provide a larger contact area |
|
use less brake fluid |
|
are more easily cooled |
|
provide more braking force |
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.