Which of the fuel systems combines the injection pump and the injection nozzle in one housing?

The unit injector fuel system uniquely integrates both the injection pump and the injection nozzle into a single component. This design allows for a more compact fuel delivery system, enhancing efficiency and performance. By combining these functions, the unit injector can deliver fuel at high pressure directly into the combustion chamber, ensuring better atomization of the fuel, which promotes more complete combustion. This results in improved engine performance and reduced emissions.

Such a system is particularly beneficial in high-performance diesel engines, where accurate timing and delivery of fuel are crucial for optimal operation. The simplicity of having both the injection and nozzle combined also facilitates maintenance and can contribute to a reduction in component count within the fuel system, leading to potential savings in weight and complexity.

In contrast, other fuel systems like common rail injectors separate the fuel pump from the injector, which allows for multiple injectors to share the same high-pressure fuel supply, but does not consolidate functions in the same manner as the unit injector. Air injection systems focus on enhancing combustion with air rather than the fuel delivery mechanism, while hydraulic governing pertains to the control of fuel quantity without integrating both functions in a single unit.