Circuit controlling coolant flow to a non-linear heat exchanger through a non-linear electromechanical valve

In a thermal exchange coolant loop wherein coolant from a reservoir is pumped as regulated by the position of an electromechanical valve, through a heat exchanger for heat transfer, an electrical control circuit for said electromechanical valve to the end that the temperature of said coolant within said reservoir may be essentially maintained, via said heat transfer, at a reference constant, set point, temperature level as determined by an externally supplied signal, said electromechanical valve control circuit comprising;

• position potentiometer means for providing a linear position signal output responsively to the position of said electromechanical valve;
• non-linear compensator means responsive to said position signal output of said position potentiometer means for deriving a heat transfer signal output which is approximately linear with the coolant flow controlled by said electromechanical valve;
• temperature sensor means for providing a temperature signal output, essentially linear over a temperature range, responsively to the temperature of said coolant within said reservoir;
• differential amplifier means for receiving said heat transfer signal output from said non-linear compensator means, said temperature signal output from said temperature sensor means, and said externally supplied signal which corresponds to said reference constant, set point, temperature level and for producing an error signal which is the difference between said ((externally supplied, set point temperature signal) minus (temperature signal)) and said (heat transfer signal);
• drive amplifier means for producing a positioning drive signal to said electromechanical valve responsively to said error signal from said differential amplifier means.