Heating passenger compartment for very different external temperatures involves controling cooling water flow so temperature drop across cooling devices and bypass lines remains constant

摘要

The method involves using 2 cooling devices in series with a thermostatically controled bypass valve with an auxiliary controler to separate the cooling devices from the cooling water circuit when heating the passenger compartment. 3-way valves control the cooling water flow so the temperature drop across the cooling devices and bypass lines is constant irrespective of external temperature for a highly constant valve cross-section or flow rate. The method involves using two cooling devices (Rc) in series in the cooling water circuit of an internal combustion engine (M) with a thermostatically controled bypass valve (905i) with electromagnetic auxiliary control to separate the cooling devices from the cooling water circuit using the auxiliary controler when heating the passenger compartment. Three-way valves (13) in the lines (12,16) to the first cooler and between the coolers control the flow of cooling water through the cooling devices and bypass lines (14) branching off the valves so that the cooling water temperature drop across the cooling devices and bypass lines remains constant irrespective of the external temperature for a highly constant valve cross-section or flow rate.