Vehicle temperature control apparatus

A temperature control apparatus for controlling a temperature in an enclosure, comprising:

• air flow duct means communicating with the enclosure and having cooling means, heating means and air mix door means for controlling a proportion of air passing through the heating means;
• outlet temperature sensor means for sensing an outlet temperature of the cooling means;
• set means for setting a command enclosure temperature for the enclosure;
• enclosure temperature sensor means for sensing an actual enclosure temperature in the enclosure;
• and
• operation control means for turning the cooling means on and off, the operation control means being constructed to control the cooling means in such a manner that the outlet temperature of the cooling means is controllably varied within predetermined limits in accordance with a difference between the set command enclosure temperature and the actual enclosure temperature to thereby minimize the time the cooling means is energized;
• the operation control means being constructed to compute a control on temperature and a control off temperature as predetermined functions of the command enclosure temperature and the actual enclosure temperature, turn the cooling means on when the outlet temperature is higher than the control on temperature and turn the cooling means off when the outlet temperature is lower than the control off temperature;
• the operation control means comprising differential amplifier means having inputs connected to outputs of the set means and enclosure temperature sensor means respectively, upper and lower clamp means connected to an output of the differential amplifier means and comparator means provided with a hysterisis function and having inputs connected to outputs of the upper and lower clamp means and the outlet temperature sensor means respectively.