Pressure control for IC engine coolant circuit - has float monitored coolant level in expansion tank and with two-level pressure control

摘要

The coolant circuit for the IC engine (2) has connecting lines (11a,11b) to each side of a main expansion tank (10). The tank is vented by a first pressure control valve (14) into a second expansion tank (16) at atmos. pressure. A second venting valve (18) at higher pressure also vents into the second tank. The action of the first valve can be blocked by a solenoid valve (15) operated via a magnetic float (20) in the main expansion tank. The float is a reed relay type and provides a simple level reading to the processor control. If the level is above a set value, with the engine switched off, then the solenoid valve is closed. This enables the system pressure to be at a higher level to prevent undue loss of coolant while the engine cools. ADVANTAGE - Simple pressure control to cover engine cooling period.