in an assembly including a diesel engine , a fluid coupling connected to the flywheel of the diesel engine , a comminuting machine and a conveyor for feeding the comminuting machine , a fluid coupling module is common to various output power train assemblies . slip speed of the fluid coupling between impeller input and runner output shafts is measured , and modulates or regulates the process feed rate of the conveyer . an electrically actuated control valve acts as an oil flow diverter valve directing oil into the fluid coupling impeller when a signal to engage the coupling is given , and in response to a signal from an over - temperature sensor when the temperature of circuit oil leaving the element exceeds a preset set point value , diverts the oil to a reservoir , thereby permitting the impeller and runner cavity to evacuate , which separates the engine from the load .