| Questions | 5 |
| Topics | Brakes, Combustion Chamber, Compression Stroke, Muffler, Wheel Hub |
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.
The combustion chamber is located in the cylinder head and contains the combustion of the air-fuel mixture. This mixture is delivered by an intake valve and the waste gases from combustion are removed from the combustion chamber by the exhaust valve.
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.
The muffler follows the catalytic converter and absorbs sound to help quiet load exhaust. It is followed by the exhaust pipe which is the final exit point for exhaust gas from the vehicle.
The wheel hub is the mounting point for the wheel and tire assembly. The wheel hub can rotate while being held stable by the steering knuckle which applies the motion of the control arms to the wheels.