Blower control for vehicle with start-stop engine

Patent metadata

Field	Value
Publication number	US-9662959-B2
Application number	US-201213710823-A
Country	US
Kind code	B2
Filing date	Dec 11, 2012
Priority date	Dec 11, 2012
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

A method and apparatus for controlling blower speed of an air conditioning system in a vehicle having a start/stop engine. When an auto stop event of the start/stop engine is entered, an ambient temperature and a second temperature (e.g., evaporator) of the air conditioning system are measured by sensors. A first cutback limit is determined in response to the ambient temperature. The blower speed is ramped to the first cutback limit by a controller. The engine is restarted and the blower speed is restored in response to the second temperature reaching a restart threshold.

First claim

What is claimed is:

1. A method of controlling blower speed of an air conditioning system in a vehicle having a start/stop engine, comprising, in order:
entering an engine stop event;
measuring an outside temperature and an evaporator temperature;
determining first cutback limit in response to the outside temperature;
in response to the blower speed exceeding the first cutback limit, ramping down blower speed to the first cutback limit; and
restarting the engine and restoring the blower speed in response to evaporator temperature reaching a restart threshold.

2. The method of claim 1 , further comprising the steps, in order, of:
after ramping the blower speed to the first cutback limit, comparing evaporator temperature to a second threshold;
in response to the evaporator temperature being above the second threshold, then further reducing ramping down the blower speed to a second cutback limit.

3. The method of claim 2 wherein the second cutback limit is comprised of a fixed speed.

4. The method of claim 3 wherein the fixed speed is zero.

5. The method of claim 2 further comprising the step of determining the second cutback limit in response to the outside temperature.

6. The method of claim 2 further comprising the steps of
measuring a sunload; and
determining the second cutback limit in response to the sunload.

7. The method of claim 2 further comprising the steps of:
measuring a passenger comfort parameter; and
determining the second cutback limit in response to the passenger comfort parameter.

8. The method of claim 1 further comprising the step of measuring a sunload, wherein the first cutback limit is further determined in response to the sunload.

9. The method of claim 1 , further comprising the steps, in order, of:
after ramping the blower speed to the first cutback limit, comparing the air conditioning system evaporator temperature to a second threshold;
measuring a sunload;
in response to the air conditioning system evaporator temperature being above the second threshold and the sunload being below a sunload threshold then further reducing the blower speed to a second cutback limit lower than the first cutback limit.

10. An air conditioning system for a vehicle having a start/stop engine, comprising:
a blower motor for driving a blower fan according to a variable blower speed;
an evaporator for receiving an air flow driven by the blower fan;
a plurality of sensors for measuring an external ambient temperature and an evaporator temperature, wherein at least one of the plurality of sensors is an external ambient temperature, and wherein at least one of the plurality of sensors is an evaporator temperature sensor; and
a controller coupled to the blower motor and the plurality of sensors for setting the blower speed according to the steps, in order, of:
detecting entry to an automatic stop event of the engine;
in response to the blower speed being above a first cutback limit, ramping the blower speed to the first cutback limit;
comparing the evaporator temperature to a restart threshold, and in response to the evaporator temperature being above the restart threshold, then initiating a termination of the automatic stop event;
in response to the evaporator temperature being below the restart threshold, then comparing the ambient temperature to a temperature threshold, and in response to the ambient temperature being less than the temperature threshold, then:
compares the evaporator temperature to an arrest threshold; and
in response to the evaporator temperature rising above the arrest threshold, then ramping the blower speed to an arrested limit, wherein the arrested limit is lower than the first limit.

11. The system of claim 10 wherein the controller stores an operating value of blower speed that was in effect prior to applying the first limit, and wherein after the step of initiating a termination of the automatic stop event the controller returns the blower speed to the operating value of blower speed that was in effect prior to applying the first limit.

12. The system of claim 10 , wherein the plurality of sensors further includes a sunload sensor which measures a sunload on the vehicle, and wherein the controller does not reduce the blower speed to the arrested limit in response to the sunload being greater than a sunload threshold.

13. The system of claim 10 wherein the arrested limit is comprised of a speed of zero.

14. The system of claim 10 wherein the controller applies the first limit by lowering the blower speed at a first ramp rate, and wherein the controller applies the arrested limit by lowering the blower speed at a second ramp rate that is slower than the first ramp rate.

15. The system of claim 10 wherein the plurality of sensors further includes a sensor which measures a passenger comfort parameter, and wherein the controller selects one of a plurality of values for the arrested limit of the blower speed in response to the passenger comfort parameter.

16. The system of claim 15 wherein the plurality of sensors further includes a humidity sensor which measures a humidity, wherein the passenger comfort parameter is comprised of the measured humidity, and wherein one of the plurality of values is zero.

17. A method of controlling blower speed of an air conditioning system in a vehicle having a start/stop engine, comprising the steps, in order, of:
entering an automatic stop event;
in response to the blower speed being above a first limit, ramping the blower speed to the first limit;
comparing an evaporator temperature to a restart threshold, and in response to the evaporator temperature being above the restart threshold then initiating a termination of the automatic stop event;
in response to the evaporator temperature continuing to be below the restart threshold after the blower speed reaches the first limit, then comparing an ambient temperature to a temperature threshold, and in response to the ambient temperature being less than the temperature threshold, then performing, in order, the steps of:
Comparing the evaporator temperature to an arrest threshold; and
in response to the evaporator temperature rising above the arrest threshold then ramping the blower speed to an arrested limit wherein the arrested limit is lower than the first limit.

Assignees

• Ford Global Tech Llc

Inventors

• Pebley Kirk R
• Rollinson James C
• Rademacher Eric M
• Madhavan Ranganathan
• Koberstein Manfred
• Buescher Wayne F

Classifications

• B60H1/00828

  Ventilators, e.g. speed control (B60H1/00864 takes precedence) · CPC title

• B60H1/00457 Primary

  Ventilation unit, e.g. combined with a radiator (control systems for ventilators B60H1/00828) · CPC title

• B60H1/00778 Primary

  the input being a stationary vehicle position, e.g. parking or stopping · CPC title