In a diesel engine, what initiates and controls the combustion?

In a diesel engine, the timing of fuel injection is crucial for initiating and controlling the combustion process. Diesel engines operate on the principle of compression ignition, which means that air is compressed to a very high pressure, raising its temperature significantly. Fuel is then injected into this highly compressed air, where it ignites due to the elevated temperature.

The timing of when the fuel is injected into the combustion chamber directly affects the engine’s performance, efficiency, and emissions. If the fuel is injected too early or too late, it can lead to incomplete combustion, resulting in reduced power output and increased pollution. Proper timing ensures that the fuel mixes effectively with the hot compressed air, allowing for efficient combustion at the right moment in the engine cycle.

In contrast, other components such as torque converters and spark plugs are associated with different types of engines. Torque converters are used in automatic transmissions to transfer power, while spark plugs are essential for igniting the air-fuel mixture in gasoline engines, not diesel engines. Piston velocity, while relevant to engine operation and performance, does not directly control the initiation of combustion. Thus, understanding the role of fuel injection timing is key to grasping how a diesel engine functions effectively.