| 摘要 |
PURPOSE:To provide efficient cooling according to engine rpm. by interrupting a compressor when the pressure in a refrigerating system exceeds a reference value, namely, a preset high pressure value of the refrigerating system which is reduced according to increase in engine rpm. CONSTITUTION:When a pressure sensor 10 detects a pressure of a refrigerating system, the sensor generates a detecting signal (e1) whose output level is increased according to increase in pressure P, and sends the signal via a noise filter 15 to a driving part 13 as a detecting signal (e1'). When an engine rpm. sensor 12, on the other hand, receives a revolution pulse from an ignition coil 11, the sensor 12 sends a detecting signal (e2), whose output level is reduced according to increase in revolution speed (r), to the driving part 13. When the driving part 13 compares the signals (e2) and (e1) with each other and finds that the detected pressure (e1') exceeds the reference value (e2), the part 13 cuts off the driving loop of a magnet clutch 7 to interrupt driving of a compressor 1. That is, the compressor may be interrupted when the pressure of the refrigerating system exceeds a high preset value and cooling operation may be performed efficiently according to engine rpm., whereby preventing insufficient cooling at the time of a low engine speed. |
