| 摘要 |
PURPOSE:To enhance comfortable condition and as well to aim at equalizing the operation of compressors in a direct drive type cooling unit having a plurality of compressors, for a bus, by selecting the number of operated compressors in dependence upon the difference between a vehicle compartment temperature and a set temperature and by alternately operating the respective compressors. CONSTITUTION:When a switch 42 is turned on, both comparators 28, 29 or the comparator 28 alone deliver one unit level or zero level in dependence upon a temperature difference between a room temperature 25 and a set temperature 26 or independence upon cooling load so that a circuit consisting of NANDs 30 thru. 32 and a T flip-flap 33 in combination delivers zero level or one unit level. Therefore, relays 36, 37 are actuated for stopping the compressors through clutches 2a, 2b, and then, refrigerating power is changed from its maximum to intermeidate and to zero. Further, the output Q, stability Q, of the flip-flap 33 is inverted when the output of the NAND gate 30 varies from zero to one unit level, the driven compressor is changed through the inversion of the gates 31 and 32. Thereby, both comfortable condition and the operation of the compressors may be equalized. |
