Overpressure fluid engine cooling system monitor - compares temp. and pressure sensor signals and warns of threshold difference

摘要

A monitor for an overpressure fluid cooling system, esp. for combustion engines, has a cooling fluid temp. sensor providing a corresp. signal to an analyser. The monitor reacts to cooling system leaks since the overpressure fluid can boil at much lower temp. than when the system is sealed. A second sensor provides the analyser with a signal corresp. to cooling system fluid pressure. The analyser produces an output signal when the difference between the two input signals reaches a defined min. value. The signals are compared in a differential amplifier comparison stage driving a relay switching element. Each signal has a corresp. indicator needle. One needle covers the other, which has a coaxial axle shaft until the min. difference is exceeded.