Importance

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Abstract

A temperature control system for a passenger van having individual temperature selection controls for passengers in the forward and rear sections of the passenger compartment. Separate exothermic heat exchangers for circulation of engine coolant therethrough are provided for the forward and rear passengers. Each heat exchanger is supplied by a coolant control valve and individual blowers provide a stream of forced air over the heat exchangers. A thermistor senses the temperature of the air discharge over each heat exchanger and a controller sums the sensed temperature signal with a user selected relative temperature reference signal provided independently by the forward and/or rear passenger selector inputs and a valve position signal; and, the controller generates a control signal proportional to the summation. An electrical actuator for each valve moves the valve until the sum is a null for controlling coolant flow to each heat exchanger to thereby regulate the discharge air temperature about the individually selected relative levels for the front and rear independently of the selected blower speed. Air conditioning evaporators may be disposed upstream of each of the heat exchangers; and, the thermistors sense the combined effect of heating and cooling and the system continues to modulate coolant flow to the heat exchangers for temperature regulation.

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First Claim