Engine stop valve (injection pump of distribution type)
The shutdown valve on the injection pump is used to stop the engine. It consists of a magnetic core with a tight fit and a return spring. When there is no 12-volt voltage on the coil from the EVE control unit, the spring presses the core firmly against the seat, the fuel mixture is stopped, and fuel is no longer injected into the combustion chamber. After that, the control unit monitors the actual stop of the engine. If the engine is not running, then only the overvoltage protection of the injection system remains open. If the engine continues to run, it is turned off by the fuel quantity regulator, and the failure of the stop valve is recorded in the computer's memory.
Vacuum engine stop (in-line injection pumps)
Pic. 4.78. Electro-hydraulic switch (shown by arrow)
Turning the ignition key to the off position activates the electro-hydraulic switch (pic. 4.78) which works from the depression created by the vacuum pump. When stopped, voltage is transmitted from the control unit to the coil, it tightens the core back, and both valves turn off. The fuel pump begins to supply fuel through the bypass line back to the fuel tank. In this case, the injection pump rail returns to its original position, and the engine stops.