Compensating for water pump speed variations in a tempered air system for vehicle passenger compartments.

摘要

An automatic control system for regulating the temperature of blower air discharged over a heater core (28) to a vehicle passenger compartment. A thermistor (58) is disposed to sense discharge air adjacent the heater core and provide a temperature signal. An electrical indication is provided of the condition of a servomotor driven valve (24) controlling water flow to the heater core. An electrical reference signal is provided indicative of a user selected relative change of flow discharge air temperature. A signal is provided indicating the speed of the water pump (12) circulating liquid to the heater core. The signals are summed and the valve driven until the sum is zero and the valve modulated to maintain the sum at zero for regulating blower air discharge temperature constant. <IMAGE>