| 摘要 |
PROBLEM TO BE SOLVED: To optimally monitor a refrigerant level even in the case of a low atmospheric temperature by setting to last maximum and minimum undercooling values before a maximum value and a minimum value when starting an operating phase during the phases of predetermined number of times, and then replacing it with a newly decided value. SOLUTION: A maximum value Mw and a minimum value Mn are obtained from undercooling values Uw, Um at each time interval, and used for evaluating a refrigerant level. The maximum value Uw and the minimum value Um of the undercooling value are obtained during operating phases of predetermined number of times (1). Then, the value Uw is set to the value Mw, and the value Um is set to the value Mm (2). If a speed V of a vehicle is not '0', the value Mm is subtracted from the value Mw to obtain a differenceΔ(4). The differenceΔis compared with a threshold value Sd, and the value Mw is compared with a threshold value Sm. If the differenceΔis smaller than the value Sd, and the value Mw is smaller than the value Sm (5), a compressor is stopped.
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