Patent GB-843068-A (GB)
Title: Improvements relating to air-conditioning installations for motor vehicles
Inventor: STUMP EUGEN
IPC: B60H1/32
Filed: 1958-07-24
Abstract: 843,068. Air conditioning unit-motor vehicles. DAIMLER-BENZ A. G. July 24, 1958, No. 23932/58. Class 137 [Also in Group XXIX] An air conditioning unit for a motor vehicle comprises a heater 8 connected to the cooling system of the vehicle engine 1, an air cooling system including a compressor 22 driven from the vehicle engine or an auxiliary motor via a hydraulic pump 30 and motor 28, the output of the pump being regulated according to the temperature of the vehicle interior (registered by thermostat 71), and a condenser 14 located with the radiator 4 of the engine at a draught intake, a cooling fan 44 being driven by the engine or an auxiliary motor via a second hydraulic pump 40 and motor 43, which pump output is regulated according to the temperature of the coolant in the engine cooling system 1 registered by a thermostat 48 in a regulating valve 47. The thermostat 71 may be initially adjusted using scale 73 and pointer lever 72. The heater 8 is located in an air duct 10 with an exit 11 leading to the vehicle interior, and an opening 12 for fresh air and aperture 13 for recirculated air. The system may be operated for either heating or cooling through switch 49, via contacts 51, 52 of leads 53, 54 for heating, and contacts 55, 56 of leads 57, 58 for cooling. Electromagnetic pilot valves 62, 63 for heating and cooling respectively, control the flow of compressed air to a cooling control valve 67 and a heating control valve 68 which are operated by lever 69 and rod 70 regulated by thermostat 71 located in opening 13. A further thermostat (not shown) may be fitted behind fan 61 in air duct 10 to act in parallel with thermostat 71 on the rod 70. For the heating cycle, the fan 61 runs at a low speed, while compressed air via valves 62 and 68 operates piston 76 which thus regulates the flap 79 for entry of fresh air through 12 and the flap 80 for circulated air via 13. A water regulating valve 82, also controlled by the compressed air through valve 68, allows hot water to flow from the engine 1 to the heater 8. During this cycle the cooling fan 44 is initially idle but valve 47 is so arranged that with increasing cooling water temperature, valve 47 closes so that pump 40 is thus connected to motor 43 which drives fan 44 at an increasing speed. During the cooling cycle fan 61 runs at a higher speed, valves 63 and 67 are opened and compressed air actuates piston 86 which controls the output of oil pump 30 and hence the speed of compressor 22 which circulates cooling medium in the pipe system between the evaporator 20 and the condenser 14. With a temperature increase in the condenser and the water in the radiator 4, valve 47 operates to increase the oil supply to motor 43 and thus increases the speed of cooling fan 44. The supply of fresh air and circulated air is also adjusted by flaps 79 and 80 controlled by piston 84 which is actuated by the compressed air supply. Another embodiment incorporates a single electromagnetic pilot valve common to both cooling and heating systems, an additional compressed air pipe branching off pipe 85 to operate a further piston which controls the running speed of fan 61.