Exhaust throttling for cabin heating

Patent metadata

Field	Value
Publication number	US-9404409-B2
Application number	US-201314072334-A
Country	US
Kind code	B2
Filing date	Nov 5, 2013
Priority date	Nov 5, 2013
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

Abstract

Embodiments for heating a vehicle cabin are disclosed. In one example, a method for heating a vehicle cabin comprises closing an exhaust throttle while diverting at least a portion of throttled exhaust gas through an exhaust gas recirculation (EGR) cooler coupled upstream of the throttle, and transferring heat from the EGR cooler to a heater core configured to provide heat to the vehicle cabin. In this way, exhaust heat may be directly routed to the cabin heating system.

First claim

The invention claimed is:

1. A method for heating a vehicle cabin comprising:
closing an exhaust throttle while diverting at least a portion of throttled exhaust gas through an exhaust gas recirculation (EGR) cooler coupled upstream of the throttle, the throttle coupled downstream of an exhaust catalyst;
transferring heat from the EGR cooler to a heater core to provide heat to the vehicle cabin; and
while a temperature of the exhaust catalyst is below a threshold temperature and while the exhaust throttle is closed, retarding spark ignition timing, an amount of spark retard adjusted based on the temperature of the exhaust catalyst.

2. The method of claim 1 , wherein transferring heat from the EGR cooler to the heater core comprises operating a heater core circulation pump to pump coolant from the EGR cooler through the heater core.

3. The method of claim 2 , further comprising adjusting a flow rate of the heater core circulation pump based on an inlet temperature of the heater core.

4. The method of claim 2 , further comprising routing the coolant from the heater core to an engine before returning the coolant to the EGR cooler.

5. The method of claim 1 , wherein diverting the portion of the throttled exhaust gas through the EGR cooler includes diverting a portion of the throttled exhaust gas through the EGR cooler located inside an EGR passage while maintaining an EGR valve in the EGR passage at a more closed position, the EGR passage fluidly coupling an engine exhaust from upstream of the exhaust throttle to an engine intake, upstream of an intake compressor.

6. The method of claim 5 , wherein the EGR passage is a low pressure EGR passage.

7. The method of claim 5 , wherein the diverting further includes routing the portion of throttled exhaust gas from an outlet of the EGR cooler to the engine exhaust, downstream of the exhaust throttle, via a bypass passage.

8. The method of claim 1 , further comprising, after the temperature of the exhaust catalyst is above the threshold temperature, maintaining the exhaust throttle closed while advancing spark ignition timing.

9. The method of claim 1 , further comprising, after the temperature of the exhaust catalyst is above the threshold temperature, adjusting the exhaust throttle based on an inlet temperature of the heater core.

10. The method of claim 9 , wherein the adjusting includes, as the inlet temperature of the heater core increases, shifting the exhaust throttle from a more closed position to a more open position.

11. A vehicle system, comprising:
an engine including an intake and an exhaust;
an exhaust gas recirculation (EGR) passage coupling the exhaust to the intake, the EGR passage including an EGR cooler and an EGR valve;
an EGR bypass coupled across the EGR cooler;
a cabin heating system including a heater core and a circulation pump configured to pump coolant from the EGR cooler to the heater core;
an exhaust throttle positioned in the exhaust downstream of an inlet of the EGR passage and upstream of an outlet of the EGR bypass, and
a controller including instructions to, while a temperature of an exhaust catalyst is below a threshold temperature and while the exhaust throttle is closed, retard spark ignition timing, an amount of spark retard adjusted based on the temperature of the exhaust catalyst,
wherein the exhaust throttle is coupled downstream of the exhaust catalyst.

12. The vehicle system of claim 11 , wherein the controller further includes instructions to, during a cabin heating mode, close the exhaust throttle and the EGR valve to push throttled exhaust through the EGR cooler and back to the exhaust via the EGR bypass to heat the EGR cooler.

13. The vehicle system of claim 12 , wherein the controller includes further instructions to adjust a flow rate of the coolant based on a heater core inlet temperature.

14. The vehicle system of claim 13 , wherein the controller includes further instructions to deactivate the circulation pump when the heater core inlet temperature is below a threshold temperature and activate the circulation pump when the heater core inlet temperature is above the threshold temperature.

15. A method, comprising:
adjusting a flow rate of coolant pumped from an exhaust gas recirculation (EGR) cooler to a cabin heating system heater core based on an inlet temperature of the heater core; and
during select conditions, throttling exhaust gas to increase exhaust pressure and to route the exhaust gas through the EGR cooler, heat from the exhaust gas transferred to the heater core via the EGR cooler, wherein the flow rate is further adjusted based on a determined change in temperature across the cooler after unthrottling the exhaust gas responsive to a temperature of the heater core reaching a threshold.

16. The method of claim 15 , wherein the select conditions comprise one or more of only when an exhaust catalyst temperature is below a first threshold temperature and the inlet temperature of the heater core is below a second threshold temperature.

17. The method of claim 15 , wherein throttling the exhaust gas comprises closing an exhaust throttle positioned in the engine exhaust, the method further comprising responsive to an EGR valve downstream of the EGR cooler being closed, routing the throttled exhaust from the EGR cooler back to the engine exhaust, downstream of the exhaust throttle, via an EGR bypass.

18. The method of claim 17 , further comprising responsive to the EGR valve being at least partially open, routing exhaust from the EGR cooler to an engine intake.

19. The method of claim 15 , wherein adjusting a flow rate of coolant based on the inlet temperature of the heater core further comprises operating a heater core circulation pump to route coolant to the heater core only when a temperature of the coolant at an outlet of the EGR cooler is above a threshold temperature.

Assignees

• Ford Global Tech Llc

Inventors

• Pursifull Ross Dykstra

Classifications

• F02N2200/0804

  Temperature inside the vehicle cabin · CPC title

• F02D9/04 Primary

  concerning exhaust conduits (throttle valves, or arrangements thereof in conduits F02D9/08) · CPC title

• F01N5/02 Primary

  the devices using heat · CPC title

• F02D21/08

  the other gas being the exhaust gas of engine · CPC title

• Y02T10/47

  Cross-Sectional Technologies · mapped topic