In a fuel injected system, fuel is injected into the manifold when?

In a fuel-injected system, fuel is injected into the manifold primarily when the inlet valve opens. This timing is crucial for the effective mixing of air and fuel within the intake manifold. Once the inlet valve is open, the air enters the engine's cylinder during the intake phase, and the fuel injected into the manifold mixes with the incoming air. This mixture is essential for achieving optimal combustion during the compression stroke.

Injecting fuel at the correct moment, specifically when the inlet valve is open, ensures that the fuel is properly atomized and distributed throughout the air entering the cylinder. This process enhances engine efficiency, performance, and reduces emissions. Understanding this timing helps in realizing how fuel injection contributes to the overall function of an internal combustion engine.