The spring identified by code K 27210 is a precision-calibrated component that regulates the opening pressure of the fuel injection valve in the ZV40/48 diesel engine. This spring is responsible for ensuring that fuel is injected into the combustion chamber at the exact moment and pressure required for optimal combustion. Its tension characteristics must remain consistent over thousands of cycles, resisting fatigue and deformation. As a vital part of the fuel system, this spring contributes directly to combustion efficiency, power output, and emission control.