What factor primarily affects the performance of mechanical injectors?

The performance of mechanical injectors is primarily influenced by the injector design and fuel quality. The injector design determines how fuel is atomized and delivered into the combustion chamber, which directly affects the efficiency and power output of the engine. A well-designed injector will optimize fuel flow, ensuring a fine mist that can mix effectively with air for efficient combustion.

In addition to design, fuel quality plays a significant role as different fuels have varying properties such as viscosity, volatility, and energy content. High-quality fuels facilitate better combustion and energy extraction, while poor-quality fuels can lead to incomplete combustion, increased emissions, and reduced engine performance.

While ambient temperature can affect injector performance to some extent, it is generally less critical compared to the inherent design and the characteristics of the fuel being used. Piston size and exhaust valve timing also influence engine dynamics and performance, but they do not directly impact the functioning of mechanical injectors the way injector design and fuel quality do.