Control method for thermo-electric heating of a vehicle seat

Abstract

Conditioned air discharged from a vehicle heating, ventilation and air conditioning (HVAC) unit is further conditioned by a thermoelectric (TE) air temperature control module and then directed to air passages in a vehicle seat. Activation of the TE air temperature control module is based on climate control parameters utilized by the HVAC unit, including the set temperature and the cabin air temperature.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a vehicle including an HVAC system, a TE air temperature control module and a vehicle seat;

FIG. 2 is a diagram of the TE air temperature control module of FIG. 1;

FIG. 3 is a diagram of a microprocessor-based HVAC controller for carrying out the control method of the present invention;

FIG. 4 is a graph illustrating transient and steady-state regimes of the control of the present invention;

FIG. 5 is a graph depicting first and second target seat temperature schedules and an interpolated target seat temperature determined according to this invention;

FIG. 6 is a graph depicting the determined target seat temperature vs. cabin air temperature for various values of the HVAC set temperature; and

FIGS. 7A, 7B and 7C together form a flow diagram representing a software routine executed by the HVAC controller of FIG. 3 for carrying out the control of the present invention.

Claims

1. A method of operation for a thermoelectric air temperature control module that delivers conditioned air to a passenger seat of a vehicle, where the vehicle additionally includes a heating, ventilation and air conditioning (HVAC) unit, the method comprising the steps of: measuring a temperature of air in a cabin of said vehicle;determining a target seat temperature during a heating mode of said HVAC unit based on a set temperature of said HVAC unit and the measured cabin air temperature;measuring a temperature of said seat; andcontrolling an operating mode and an activation level of said thermoelectric air temperature control module to bring the measured seat temperature into conformance with said target seat temperature.

2. The method of claim 1, including the steps of: decreasing the activation level of said thermoelectric air temperature control module to provide less seat heating when the operating mode of said thermoelectric air temperature control module is heating and said measured seat temperature is above the target seat temperature by at least a calibrated value;increasing the activation level of said thermoelectric air temperature control module to provide more seat heating when the operating mode of said thermoelectric air temperature control module is heating and said measured seat temperature is below the target seat temperature by at least said calibrated value; andchanging the operating mode of said thermoelectric air temperature control module from heating to cooling when said measured seat temperature is above the target seat temperature by at least said calibrated value and the activation level of said thermoelectric air temperature control module has been decreased to a minimum level.

3. The method of claim 2, including the steps of: increasing the activation level of said thermoelectric air temperature control module to provide more seat cooling when the operating mode of said thermoelectric air temperature control module is cooling and said measured seat temperature is above the target seat temperature by at least said calibrated value;decreasing the activation level of said thermoelectric air temperature control module to provide less seat cooling when the operating mode of said thermoelectric air temperature control module is cooling and said measured seat temperature is below the target seat temperature by at least a calibrated value; andchanging the operating mode of said thermoelectric air temperature control module from cooling to heating when said measured seat temperature is below the target seat temperature by at least said calibrated value and the activation level of said thermoelectric air temperature control module has been decreased to the minimum level.

4. The method of claim 1, including the steps of: controlling said thermoelectric air temperature control module to provide maximum heating of the air delivered to said passenger seat upon initial activation of said HVAC unit in said heating mode.

5. The method of claim 1, where the step of determining the target seat temperature includes the steps of: determining a first target seat temperature based on the measured cabin air temperature using a schedule derived for cabin temperatures greater than a calibrated upper temperature; andadjusting said first target seat temperature upward based on a deviation of the measured cabin air temperature below said calibrated upper temperature to form said target seat temperature.

6. The method of claim 1, where the step of determining the target seat temperature includes the steps of: determining a nominal target seat temperature based on the measured cabin air temperature, using a schedule derived for a nominal value of said set temperature; andadjusting said nominal target seat temperature up or down based on a deviation of said set temperature above or below said nominal value to form said target seat temperature.

7. The method of claim 1, including the step of: limiting the determined target seat temperature to a calibrated maximum value.