Auxiliary Heater Pump Control

• US 20100230505A1
• Filed: 03/12/2009
• Published: 09/16/2010
• Est. Priority Date: 03/12/2009
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Ribadeneira, Marcelo X., Ziehr, Lawrence P.
• Granted Patent: US 8,807,445 B2
• Time in Patent Office: Days
• US Class Current: 237/5
• CPC Class Codes: B60H 1/004 for vehicles having a combustion engine and electric drive means, e.g. hybrid electric vehicles
• CPC Class Codes: B60H 1/034 from the cooling liquid of the propulsion plant and from an electric heating device
• CPC Class Codes: F01P 2060/08 Cabin heater

Abstract

A method of auxiliary heater pump control in a vehicle including a heater core and an auxiliary pump in a heater core branch of a vehicle coolant system is disclosed. The method comprises the steps of: determining if a power plant is on, the power plant being connected to the coolant system; calculating an estimated heating power required to meet HVAC system heating requirements that is a function of mass air flow, specific heat, and a change in temperature in a passenger compartment; determining if the calculated estimated heating power required is greater than a minimum required heating power that will be able to maintain thermal comfort in the passenger compartment of the vehicle; and if the calculated estimated heating power required is greater than the minimum required heating power and the power plant is not on, activating the auxiliary pump to pump a coolant through the heater core.

Claims

1. A method of auxiliary heater pump control in a vehicle including a heater core and an auxiliary pump in a heater core branch of a vehicle coolant system, the method comprising the steps of:

(a) determining if a power plant is on, the power plant being connected to the coolant system;

(b) calculating an estimated heating power required to meet HVAC system heating requirements that is a function of a mass air flow, a specific heat, and a change in temperature in a passenger compartment;

(c) determining if the calculated estimated heating power required is greater than a minimum required heating power that will be able to maintain thermal comfort in the passenger compartment of the vehicle; and

(d) if the calculated estimated heating power required is greater than the minimum required heating power and the power plant is not on, activating the auxiliary pump to pump a coolant through the heater core.

2. The method of claim 1 wherein step (d) is further defined by activating an auxiliary coolant heater in the heater core branch if the calculated estimated heating power required is greater than the minimum required heating power and the power plant is not on.

3. The method of claim 1 wherein step (d) is further defined by initializing a predetermined minimum auxiliary pump on-time when activating the auxiliary pump and maintaining the auxiliary pump on for at least the predetermined minimum auxiliary pump on-time.

4. The method of claim 1 wherein step (a) is further defined by deactivating the auxiliary pump if the power plant is on.

5. The method of claim 1 wherein step (b) is further defined by determining a maximum value between a desired blower power and a minimum blower power for a blower forcing air through the heater core, and multiplying this maximum value by a blower conversion factor that converts a blower power into an air flow volume to get an air flow value, and then dividing the air flow value by an air density value to determine the mass air flow.

6. The method of claim 5 wherein step (b) is further defined by subtracting a target evaporator temperature from a target temperature and multiplying by a heat gain factor to determine the change in temperature.

7. The method of claim 6 wherein step (b) is further defined by multiplying the change in temperature by the mass air flow and the specific heat to produce an initial estimated heating power required.

8. The method of claim 7 wherein step (b) is further defined by limiting the initial estimated heating power required to between zero and a predetermined maximum heat power capability to determine the estimated heating power required.

9. The method of claim 1 wherein step (b) is further defined by subtracting a target evaporator temperature from a target temperature and multiplying by a heat gain factor to determine the change in temperature.

10. The method of claim 1 wherein step (a) is further defined by the power plant being an internal combustion engine.

11. A method of auxiliary heater pump control in a vehicle including a heater core and an auxiliary pump in a heater core branch of a vehicle coolant system, the method comprising the steps of:

(a) determining if a power plant is on, the power plant being connected to the coolant system;

(b) calculating an estimated heating power required to meet HVAC system heating requirements that is a function of a mass air flow, a specific heat, and a change in temperature in a passenger compartment;

(c) determining if the calculated estimated heating power required is greater than a minimum required heating power that will be able to maintain thermal comfort in the passenger compartment of the vehicle;

(d) if the calculated estimated heating power required is greater than the minimum required heating power and the power plant is not on, activating the auxiliary pump to pump a coolant through the heater core and activating an auxiliary coolant heater in the heater core branch to warm the coolant flowing through the auxiliary pump; and

initializing a predetermined minimum auxiliary pump on-time when activating the auxiliary pump and maintaining the auxiliary pump on for at least the predetermined minimum auxiliary pump on-time.

12. The method of claim 11 wherein step (a) is further defined by deactivating the auxiliary pump if the power plant is on.

13. The method of claim 11 wherein step (b) is further defined by determining a maximum value between a desired blower power and a minimum blower power for a blower forcing air through the heater core, and multiplying this maximum value by a blower conversion factor that converts a blower power into an air flow volume to get an air flow value, and then dividing the air flow value by an air density value to determine the mass air flow.

14. The method of claim 13 wherein step (b) is further defined by subtracting a target evaporator temperature from a target temperature and multiplying by a heat gain factor to determine the change in temperature.

15. The method of claim 14 wherein step (b) is further defined by multiplying the change in temperature by the mass air flow and the specific heat to produce an initial estimated heating power required.

16. The method of claim 15 wherein step (b) is further defined by limiting the initial estimated heating power required to between zero and a predetermined maximum heat power capability to determine the estimated heating power required.