Control system for fuel pump of engine - eliminates fuel vapour bubbles in supply links by using temp. and time controls for pump

摘要

The electronic control system switches on the pump by a relay (15) when the temperature of the engine rises above a given limit and depending on the pressure of the fuel in the fuel metering system. The pump is switched off again depending on pressure and/or time. The given temp. limit is c. 75 degrees C. set by a thermo switch (11). A timing circuit is triggered by the edge of the pump's control signal. When the pressure, as detected by a pressure switch (20) drops within a given preset time interval, the timing circuit prevents the pump being actuated again. The advantage lies in preventing fuel vapour bubbles forming in the fuel lines -- or at least restricts their formation.