What determines the amount of fuel that reaches the combustion chamber as engine speed decreases?

The amount of fuel that reaches the combustion chamber as engine speed decreases is significantly influenced by low fuel pressure combined with the longer duration that the injector is open. In such scenarios, as the engine speed drops, the vacuum created in the intake manifold increases the fuel flow into the combustion chamber, necessitating longer opening times for the fuel injectors to deliver the required fuel volume.

When engine speed decreases, there is less air being drawn in, and to maintain the correct air-fuel mixture, the injector must compensate by staying open longer. This adjustment allows for adequate fuel delivery under lower operating conditions. Furthermore, low fuel pressure allows the injectors to function correctly without creating a high-pressure situation that could lead to fuel atomization issues, ensuring the fuel can flow smoothly and efficiently into the combustion chamber.

In summary, the combination of low fuel pressure with extended injector opening times is critical in ensuring that the right amount of fuel reaches the combustion chamber when the engine speed is low, facilitating optimal combustion and engine performance.