Off-road air conditioning control
AssigneeEagle Engineering and Manufacturing, Inc.
InventorAndrew J. Pichotta
Life of this patent
Estimating the term…
Abstract
Apparatus for heating and cooling an enclosed operator space in an off-road vehicle controlling evaporator fan speed, compressor clutch and condenser fan operation, and having sensors for detecting operator space temperature and an evaporator freezing condition, the condenser fan motor fuse condition, and under or over pressure conditions in the compressor; the apparatus also controls the operation of a heat source such as a heat valve in a coolant path or an electric resistance heater. The evaporator fan speed is controlled by pulse-width modulating power to the fan motor and speed is displayed by a bar graph; a digital display of temperature and system diagnostics is also provided. Operation of the clutch is inhibited when the evaporator freezes.
Claims25
Apparatus for heating and cooling an enclosed operator space in an off-road vehicle comprising:
- a) fan speed control means for controlling the speed of an evaporator fan to circulate air past an evaporator coil and into the enclosed operator space in an off-road vehicle;
- b) compressor clutch control means for controlling energization of an electromagnetic clutch connected between a prime mover and an air conditioning compressor;
- c) condenser fan control means for selectively energizing a fan to blow air across a condenser coil;
- d) a first sensor circuit connected to sense the presence or absence of electrical continuity to the condenser fan and providing a two-state electrical signal representative thereof;
- e) a second sensor circuit connected to a pressure switch coupled to sense refrigerant pressure at an output of the compressor and providing a two-state signal representative of whether the refrigerant pressure at the compressor output is within a predetermined pressure range;
- f) an operator space temperature sensor located in a flow path of the air circulating in the enclosed operator space and providing a signal representative thereof;
- g) microprocessor system control means connected to the first and second sensor circuits and having an operator adjustable temperature input means for selecting a desired temperature for enabling operation when electrical continuity is present and the refrigerant pressure is within the predetermined pressure range wherein the system control means actuates the compressor clutch control means when the signal from the operator space temperature sensor indicates a temperature above the desired temperature;
- h) a heating control loop for providing heat to increase the temperature in an operator space in the off-road vehicle;
- and
- i) HEAT mode control means for controlling energization of the heating loop
- wherein the microprocessor system control means is operative to energize the heating control loop when the signal from the operator space temperature sensor indicates a temperature below the desired temperature.
The apparatus of claim 17 wherein the microprocessor system control means further comprises a third sensor circuit for receiving a evaporator condition signal from the evaporator condition sensing means representative of whether the evaporator is frozen or not.
Dependencies are inferred from the claim text.