Most fuel injection nozzles are actuated by ______.

Most fuel injection nozzles are actuated by fuel oil pressure. This method is commonly employed in diesel engines, where high-pressure fuel is delivered to the nozzle from the fuel injection system. The fuel pressure serves to overcome the opening pressure of the nozzle, causing it to spray a fine mist of fuel directly into the combustion chamber at precisely timed intervals.

Using fuel pressure allows for a more efficient and responsive injection system, as it can adapt to various engine speeds and loads, ensuring optimal fuel atomization and performance. The system can be designed to work with varying pressure levels, contributing to better combustion efficiency and reduced emissions. Other methods, such as mechanical actuation mechanisms involving cams or springs, are less common for actuating fuel injection nozzles in modern engines, primarily due to the increasing demand for efficiency and precision in fuel delivery.