| Questions | 5 |
| Topics | Air-Fuel Mixture, Combustion, Radiator, Solenoid, Wheel Hub |
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.
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.
The radiator is responsible for tranferring heat from the coolant to the outside air. Radiator hoses transfer coolant to and from the engine to the radiator and a radiator cap maintains pressure in the cooling system to increase the boiling point of the coolant mixture and thus allow it to absorb more heat.
The cylindrical solenoid is a relay that safely connects the high amperage battery to the starter motor when the ignition key is turned. This current then allows the engine to turn at a high enough speed to start.
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.