Fast response control for car heater - with temp. sensing diodes having passenger compartment sensor more responsive than heat exchanger sensor

摘要

The car heating system has temp. sensing diodes to monitor the heat output from the heat exchanger as well as the temp. inside the vehicle. The two sensors are coupled in series, and for a fast response system the temp. dependent characteristics of the internal sensor are greater than that of the heat exchanger sensor. For accuracy the internal sensor is mounted in the of a sampling tube into which air is drawn using the engine inlet vacuum. This eliminates errors due to sunlight on the sensor etc. The system provides a fast heating control to the selected temp.