System and method for defogging a vehicle window
First Claim
1. A method for controlling a heating, ventilation and air conditioning (HVAC) system of a vehicle which discharges a flow of air to a passenger cabin of the vehicle, the system including a variable speed blower, a ducting, a compressor, an evaporator, a heater core for heating air in the ducting, a control element having control positions for varying refrigerating and heating capacity of the HVAC system, a pressure cycling switch for controlling operation of the compressor, a plurality of blend doors having various control positions for controlling direction of air flow and ratio of fresh air to recirculated air, a humidity sensor for sensing relative humidity within the passenger cabin and providing a corresponding relative humidity signal, and temperature sensors for sensing temperature within the passenger cabin, the evaporator, and ambient temperature and providing a corresponding passenger cabin temperature signal, an evaporator temperature signal and an ambient temperature signal, the method comprising the steps of:
- measuring the ambient temperature and generating the ambient temperature signal;
measuring the temperature of the evaporator and generating the evaporator temperature signal;
bypassing the pressure cycling switch when the ambient temperature signal is below 42°
F.;
cycling the control element on and off according to a predetermined duty cycle when the ambient temperature signal is below 42°
F. and above 20°
F.; and
moving the plurality of blend doors to a predetermined position based upon the ambient temperature signal and the evaporator temperature signal.
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Accused Products
Abstract
There is disclosed a system and method for preventing fogging of the windows of an automotive vehicle. The system and method operate the air conditioning system of the vehicle at temperatures where a high degree of probability of fogging exists. The method includes the steps of measuring the ambient temperature, the evaporator core temperature and operating the air conditioning compressor at specific duty cycles depending upon these temperatures. The duty cycle will be determined based upon these temperature variables as well as the relative humidity within the passenger cabin of the vehicle.
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Citations
7 Claims
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1. A method for controlling a heating, ventilation and air conditioning (HVAC) system of a vehicle which discharges a flow of air to a passenger cabin of the vehicle, the system including a variable speed blower, a ducting, a compressor, an evaporator, a heater core for heating air in the ducting, a control element having control positions for varying refrigerating and heating capacity of the HVAC system, a pressure cycling switch for controlling operation of the compressor, a plurality of blend doors having various control positions for controlling direction of air flow and ratio of fresh air to recirculated air, a humidity sensor for sensing relative humidity within the passenger cabin and providing a corresponding relative humidity signal, and temperature sensors for sensing temperature within the passenger cabin, the evaporator, and ambient temperature and providing a corresponding passenger cabin temperature signal, an evaporator temperature signal and an ambient temperature signal, the method comprising the steps of:
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measuring the ambient temperature and generating the ambient temperature signal; measuring the temperature of the evaporator and generating the evaporator temperature signal; bypassing the pressure cycling switch when the ambient temperature signal is below 42°
F.;cycling the control element on and off according to a predetermined duty cycle when the ambient temperature signal is below 42°
F. and above 20°
F.; andmoving the plurality of blend doors to a predetermined position based upon the ambient temperature signal and the evaporator temperature signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification
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- Resources
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Current AssigneeVisteon Global Technologies Incorporated (Visteon Corporation)
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Original AssigneeFord Motor Company
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InventorsDage, Gerhard Allan
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Primary Examiner(s)ATKINSON, CHRISTOPHER MARK
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Application NumberUS09/087,881Time in Patent Office827 DaysField of Search62/176.6, 62/180, 62/203, 62/229, 236/13, 236/44 C, 165/42, 165/43, 165/202, 165/204, 165/228, 165/249, 165/225, 165/263US Class Current165/202CPC Class CodesB60H 1/3207 for minimizing the humidity...
