We come first to the ignition system of an internal combustion engine that depends on the type of engine and the fuel being used in the unit. A precisely timed spark would ignite petrol engines, while it is through compression heating that would ignite diesel engines.
Ignition of a spark ignition engine, would result from a mixture of an electric spark from a spark plug, with a controlled and precise timing. This type of ignition is applicable to almost all gasoline engines, while the timing of diesel engines is controlled precisely by the pressure pump and injector.
Because of the heat generated by the air compression during the compression stroke, there is an ignition which would happen as the fuel and air mixture temperature has taken over the autoignition temperature. Be informed that diesels are the vast majority of compression ignition, of which there is mix of air and fuel once the air has reached the temperature of ignition.
Note that fuels burn faster and more efficiently when there is a large representation of surface area to the oxygen in air. The traditional way to atomize liquid fuels, which is needed to create a fuel air mixture, is to have it done with a carburetor in petrol engines and with the fuel injection in diesel engines. Fuel injection is also used by many modern petrol engines today although there is difference in the technology.
In order to supply fuel into the cylinder, the use of carburetor is used in simpler reciprocating engines. From the mid 1980s, carburetor technology in cars have attained a very high degree of precision and sophistication, but lost out on the cost and flexibility to fuel injection. Small engines though still remain to use the simple forms of carburetor, like lawn mowers and the more sophisticated forms of engines used in small motorcycles.
Vehicles that use gasoline of larger size have mostly moved to using fuel injection systems. The system of fuel injection has been always used in diesel engines and this is because the timing of the injection would kick off and controls the combustion.
Where autogas engines is concern, it uses the system of fuel injection or the open or closed loop carburetors.
Many internal combustion engines now require a fuel pump. Where diesel engines is concern, it uses an all mechanical precision pump system that produces a timed injection directly into the combustion chamber, thus requiring a high pressure of delivery so that the pressure of the combustion chamber is overcame.
Among the parts of the engine that are the key parts of a four stroke engine are as follows, the crankshaft, connecting rod, one or more camshafts, and valves.