| Questions | 5 |
| Topics | Exhaust Stroke, Ignition Coil, Oil Pump, Water Pump, Wheel Hub |
During the exhaust stroke, just before the piston reaches bottom dead center the exhaust valve opens. The resulting gases from combustion are then pushed out through the exhaust valve as the piston travels up the cylinder to top dead center, completing stroke four of the four-stroke piston cycle.
The ignition coil is a high-voltage transformer made up of two coils of wire. The primary coil winding is the low-voltage winding and has relatively few turns of heavy wire. The secondary coil winding is the high-voltage winding that surrounds the primary and is made up of thousands of turns of fine wire. Current flows from the battery through the primary coil winding which creates a changing magnetic field inside the secondary coil. This induces a very high-voltage current in the secondary coil which it feeds to the distributor.
The oil pump is driven by the camshaft and is responsible for pumping oil through the oil galleries (passages) that run throughout the engine. It also contains the oil filter and a pressure relief valve which prevents excessive pressure from building up in the lubrication system.
The water pump is driven by a belt connected to the crankshaft and ensures that coolant moves through the engine and radiator.
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.