Exhaust throttling for cabin heating

Patent metadata

Field	Value
Publication number	US-9334783-B2
Application number	US-201314072396-A
Country	US
Kind code	B2
Filing date	Nov 5, 2013
Priority date	Nov 5, 2013
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

Embodiments for heating a vehicle cabin are disclosed. In one example, a method for an engine comprises pumping coolant from a coolant reservoir to an exhaust component and then to a heater core, the coolant heated by the exhaust component, and during engine warm-up conditions, adjusting a flow rate of coolant into a heater core to maximize heat transfer to a vehicle cabin.

First claim

The invention claimed is:

1. A method for an engine, comprising:
pumping coolant from a coolant reservoir to an exhaust component and then to a heater core, the coolant heated by the exhaust component;
during engine warm-up conditions, adjusting a flow rate of coolant into the heater core in coordination with operating an exhaust throttle to increase exhaust backpressure and divert at least a portion of exhaust upstream of the throttle through the exhaust component based on a temperature drop across the heater core and a commanded flow rate of coolant into the heater core to maximize heat transfer to a vehicle cabin; and
flowing the diverted portion of exhaust exiting from the exhaust component through an ejector to generate a vacuum.

2. The method of claim 1 , wherein adjusting the flow rate of coolant into the heater core to maximize heat transfer to the vehicle cabin comprises flowing the coolant at a less-than-maximum flow rate even if a heat demand of the vehicle cabin is at a maximum heat demand.

3. The method of claim 1 , wherein adjusting the flow rate of coolant into the heater core comprises adjusting the flow rate to a desired flow rate of coolant associated with a given operating condition.

4. The method of claim 3 , wherein the desired flow rate provides maximum heat transfer to the vehicle cabin for the given operating condition.

5. The method of claim 1 , wherein the exhaust component is an exhaust gas recirculation (EGR) cooler, wherein the coolant reservoir is the engine, the method further comprising, routing the coolant into the heater core from the EGR cooler via a circulation pump and routing the coolant from the heater core through the engine before returning to the EGR cooler.

6. The method of claim 5 , wherein adjusting the flow rate comprises adjusting a flow rate of the circulation pump.

7. The method of claim 5 , wherein operating the exhaust throttle comprises closing an exhaust throttle and while diverting at least a portion of throttled exhaust gas through the EGR cooler, heat from the EGR cooler is transferred to the coolant.

8. The method of claim 7 , wherein diverting at least a portion of throttled exhaust gas through the EGR cooler includes flowing 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 passage from upstream of the exhaust throttle to an engine intake passage upstream of an intake compressor.

9. The method of claim 1 , wherein the engine warm-up conditions comprise a temperature of the engine being below a threshold temperature, the method further comprising, when the temperature of the engine is above the threshold temperature, maintaining a constant flow rate of coolant into the heater core.

10. 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;
a cabin heating system including a heater core, an exhaust throttle, and a circulation pump configured to pump coolant from the EGR cooler to the heater core;
an EGR bypass including an ejector, coupled from the EGR passage downstream of the EGR cooler to the exhaust downstream of the exhaust throttle; and
a controller operatively connected to the cabin heating system including instructions to, during a cabin heating mode, operate the circulation PUMP in coordination with the exhaust throttle to adjust a flow rate of the coolant into the heater core and an exhaust flow through the EGR bypass based on a determined relationship between a temperature drop across the heater core and the flow rate of the coolant into the heater core.

11. The vehicle system of claim 10 , wherein the controller further includes instructions to adjust the flow rate of the coolant to a desired flow rate that provides a maximum cabin power, the maximum cabin power being a function of the temperature drop across the heater core and the desired flow rate.

12. The vehicle system of claim 10 , wherein the flow rate is determined by the controller based on a power of the circulation pump.

13. The vehicle system of claim 10 , wherein the exhaust throttle is positioned in the exhaust downstream of an inlet of the EGR passage.

14. The vehicle system of claim 13 , wherein the controller further includes instructions to, during the cabin heating mode, close the EGR valve to flow exhaust gas through the EGR cooler and back to the exhaust via the EGR bypass to heat the EGR cooler.

15. A method, comprising:
pumping coolant with a circulation pump through a cabin heating circuit comprising an EGR cooler, a cabin heater core, and an engine;
during steady state conditions where a temperature of the coolant flowing into the heater core is above a threshold temperature, operating the circulation pump at maximum power to flow the coolant into the heater core at a maximum flow rate in coordination with closing of an exhaust throttle positioned in an engine exhaust passage and flowing some exhaust gas from downstream of the EGR cooler through an ejector positioned in an EGR bypass and to the exhaust passage downstream of the exhaust throttle; and
during non-steady state conditions where the temperature of the coolant flowing into the heater core is below the threshold temperature, adjusting the operation of the circulation pump to flow coolant into the heater core at a less-than-maximum flow rate in coordination with opening of the exhaust throttle, the less-than-maximum flow rate selected to provide maximum cabin heat.

16. The method of claim 15 , wherein adjusting the operation of the circulation pump comprises adjusting the power of the circulation pump based on a temperature drop across the heater core and a flow rate of the coolant into the heater core.

17. The method of claim 16 , further comprising, as the temperature drop increases, adjusting the operation of the circulation pump to increase the flow rate and as the temperature drop decreases, adjusting the operation of the circulation pump to decrease the flow rate.

18. The method of claim 15 , further comprising, during the non-steady state conditions, operating the exhaust gas throttle to increase exhaust pressure and to route exhaust gas through the EGR cooler to heat the EGR cooler.

19. The method of claim 18 , further comprising, responsive to an EGR valve downstream of the EGR cooler being closed, routing the exhaust gas from the EGR cooler back to the engine exhaust passage via the EGR bypass, and responsive to the EGR valve being at least partially open, routing the exhaust from the EGR cooler to an engine intake.

Assignees

• Ford Global Tech Llc

Inventors

• Pursifull Ross Dykstra

Classifications

• B60H1/04 Primary

  from cooling liquid of the plant {(B60H1/025, B60H1/03 take precedence)} · CPC title

• F01N5/02 Primary

  the devices using heat · CPC title

• B60H1/00 Primary

  Heating, cooling or ventilating devices · CPC title

• Y02T10/12

  Improving ICE efficiencies · CPC title