Vehicle-mounted refrigerator refrigerating device and system

The invention relates to the technical field of vehicle-mounted refrigeration, in particular to a vehicle-mounted refrigerator refrigeration device and system. A condenser is in pipeline connection with a compressor, an evaporator is in pipeline connection with the condenser, a liquid storage device is in pipeline connection with the evaporator and the compressor, an electronic expansion valve is arranged between the evaporator and the condenser, a first temperature sensing head is arranged on the outer side of a vehicle-mounted refrigerator, a second temperature sensing head is arranged at an outlet of the evaporator, the first temperature sensing head and the second temperature sensing head are both electrically connected with the electronic expansion valve, and the temperature is monitored through the first temperature sensing head and the second temperature sensing head, so that the opening degree of the electronic expansion valve is controlled to adjust the flow and the pressure ratio, and when the tempe