System and method for controlling coolant flow through a heater core of a vehicle based upon an estimated heater core air out temperature

1. A system comprising:

a temperature estimation module configured to determine an estimate of a heater core air out temperature of a vehicle based upon a heater core inlet coolant temperature, a heater core outlet coolant temperature, an estimated volumetric air flowrate, and an estimated volumetric coolant flowrate,

wherein the temperature estimation module is configured to estimate the heater core air out temperature using a least square estimation and is configured to estimate the heater core air out temperature based upon the heater core inlet coolant temperature, the heater core outlet coolant temperature, a volumetric coolant flowrate, and a volumetric air flowrate, wherein the temperature estimation module is configured to estimate the heater core air out temperature according to α 1 {dot over (ν)} clnt +α 2 {dot over (ν)} air +α 3 T Clnt,In +α 4 T Clnt,Out +α 5 , where {dot over (ν)} clnt is a volumetric coolant flowrate, {dot over (ν)} air is the volumetric air flowrate T Clnt,In is the heater core inlet coolant temperature, T Clnt,Out is the heater core outlet coolant temperature, and α i represents respective least square estimate coefficients; and

a coolant flow control module configured to:

control a coolant flowrate at which coolant flows to a heater core of the vehicle by adjusting at least one of a position of a coolant control valve of the vehicle and an output of a coolant pump of the vehicle; and

control the coolant flowrate to decrease a difference between a target heater core air out temperature and the estimated heater core air out temperature.

2. The system of claim 1 wherein the estimated heater core air out temperature is bounded by the heater core inlet coolant temperature having a predefined offset and the heater core outlet coolant temperature having a predefined offset.

3. The system of claim 1 wherein the coolant flow control module is configured to compare the difference between the target heater core air out temperature and the estimated heater core air out temperature, determine whether the difference exceeds a predefined error threshold, and controls the coolant flowrate to decrease a difference between the target heater core air out temperature and the estimated heater core air out temperature.

4. The system of claim 1 wherein the target heater core air out temperature is determined based on blower speed and ambient temperature.

5. The system of claim 1 wherein the coolant flow control module is configured to adjust the coolant flowrate based upon at least one of a predetermined coolant flowrate and a predetermined increment.

6. The system of claim 1 wherein the coolant flow control module is configured to adjust the coolant flowrate based upon at least one of a variable coolant flowrate and a variable increment.

7. The system of claim 6 wherein the variable increment is based upon a control setting.

8. The system of claim 7 wherein the control setting comprises at least one of a Proportional-Integral-Derivative (PID) control and a table look-up control.

9. The system of claim 1 , further comprising:

a heater core inlet coolant temperature sensor disposed at an heater core inlet line to measure the heater core inlet coolant temperature entering a heater core of a vehicle; and

a heater core outlet coolant temperature sensor disposed at a heater core outlet line to measure the heater core outlet coolant temperature exiting the heater core.

10. The system of claim 1 , further comprising a volumetric coolant flowrate estimation module that is configured to estimate a volumetric coolant flowrate of a coolant.

11. The system of claim 1 , further comprising an airflow estimation module that is configured to estimate a volumetric air flowrate.

12. The system of claim 1 , further comprising a heater flap control module that is configured to control a heater flap opening to control an amount of air that passes through a heater flap.

13. A system comprising:

a temperature estimation module configured to determine an estimate of a heater core air out temperature of a vehicle based upon a heater core inlet coolant temperature, a heater core outlet coolant temperature, an estimated volumetric air flowrate, and an estimated volumetric coolant flowrate,

wherein the temperature estimation module is configured to estimate the heater core air out temperature using a least square estimation and is configured to estimate the heater core air out temperature based upon the heater core inlet coolant temperature, the heater core outlet coolant temperature, a volumetric coolant flowrate, and a volumetric air flowrate wherein the temperature estimation module is configured to estimate the heater core air out temperature according to α 1 {dot over (ν)} clnt +α 2 {dot over (ν)} air +α 3 T Clnt,In +α 4 T Clnt,Out +α 5 , where {dot over (ν)} clnt is a volumetric coolant flowrate, {dot over (ν)} air is the volumetric air flowrate, T Clnt,In is the heater core inlet coolant temperature, T Clnt,Out is the heater core outlet coolant temperature, and α i represents respective least square estimate coefficients; and

a coolant flow control module configured to:

control a rate at which coolant flows to a heater core of the vehicle by adjusting at least one of a position of a coolant control valve of the vehicle and an output of a coolant pump of the vehicle, and

control the coolant flowrate to decrease a difference between a target heater core air out temperature and the estimated heater core air out temperature,

wherein the target heater core air out temperature is determined based on blower speed and ambient temperature.

14. The system of claim 13 wherein the estimated heater core air out temperature is bounded by the heater core inlet coolant temperature having a predefined offset and the heater core outlet coolant temperature having a predefined offset.

15. The system of claim 13 , further comprising:

a heater core inlet coolant temperature sensor disposed at an heater core inlet line to measure the heater core inlet coolant temperature entering a heater core of a vehicle; and

a heater core outlet coolant temperature sensor disposed at a heater core outlet line to measure the heater core outlet coolant temperature exiting the heater core.

16. The system of claim 13 wherein the coolant flow control module is configured to compare the difference between the target heater core air out temperature and the estimated heater core air out temperature, determine whether the difference exceeds a predefined error threshold, and controls the coolant flowrate to decrease a difference between the target heater core air out temperature and the estimated heater core air out temperature.

17. The system of claim 13 wherein the target heater core air out temperature is determined based on blower speed and ambient temperature.

18. The system of claim 13 wherein the coolant flow control module is configured to adjust the coolant flowrate based upon at least one of a predetermined coolant flowrate and a predetermined increment.

19. The system of claim 13 wherein the coolant flow control module is configured to adjust the coolant flowrate based upon at least one of a variable coolant flowrate and a variable increment.

20. The system of claim 19 wherein the variable increment is based upon a control setting.