Methods and systems for catalyst heating

Patent metadata

Field	Value
Publication number	US-10738672-B2
Application number	US-201916255704-A
Country	US
Kind code	B2
Filing date	Jan 23, 2019
Priority date	Jan 29, 2018
Publication date	Aug 11, 2020
Grant date	Aug 11, 2020

Abstract

Methods and systems are provided for a motor vehicle engine, a supply air system including an electrically heated exhaust gas aftertreatment device arranged in the exhaust system, an electric turbocharger including an exhaust turbine and an intake compressor. In one example, the exhaust gas aftertreatment device may be heated and the electric turbocharger may be simultaneously operated to expedite attainment of aftertreatment device light-off while maintaining emissions quality.

First claim

The invention claimed is:

1. A system for a motor vehicle comprising: an internal combustion engine, a supply air system, an exhaust system, an exhaust gas aftertreatment device arranged in the exhaust system, a turbocharger including a turbine arranged in the exhaust system upstream of the exhaust gas aftertreatment device and a compressor arranged in the supply air system, an electric machine designed to drive the turbine or the compressor, and a heater designed to supply heat to the exhaust gas aftertreatment device; and a controller storing instructions in non-transitory memory executable to: supply energy to the electric machine to operate the turbocharger; and supply energy to the heater to heat the exhaust gas aftertreatment device, energy supplied to the heater based on the energy supplied to the electric machine; wherein the heater is electrically operated, and the energy supplied to the heater is directly proportionally increased with an increase of the energy supplied to the electric machine.

2. The system of claim 1 , further comprising: an exhaust gas recirculation system which is designed to conduct an amount of exhaust gas out of the exhaust system to the supply air system, the energy supplied to the heater further based on the amount of exhaust gas recirculated to the supply air system.

3. The system of claim 1 , wherein each of the turbocharger and the heater are operated when in an E-boost check it is determined that a charge pressure undershoots a defined value, and in a temperature check it is determined that the exhaust gas aftertreatment device undershoots a defined temperature.

4. The system of claim 3 , wherein the electric machine is deactivated in response to the charge pressure being higher than the defined value and wherein the heater is deactivated in response to exhaust gas aftertreatment device light-off.

5. The system of claim 3 , wherein the defined value is based on an engine torque demand, and wherein the defined temperature is based on a light-off temperature of the exhaust gas aftertreatment device.

6. A method for an engine, comprising: in response to a lower than threshold temperature of an exhaust catalyst while an electric turbocharger is being operated, heating the catalyst via an electric heater coupled to the catalyst, a power supplied to the electric heater adjusted based on a speed of the electric turbocharger; wherein the power supplied is directly proportionally increased with an increase in the energy supplied to the electric turbocharger, the electric turbocharger driven by an electric machine coupled to one of an exhaust turbine, an electric intake compressor, and a shaft connecting the exhaust turbine to an intake compressor.

7. The method of claim 6 , wherein each of the electric turbocharger and the electric heater are powered by a common alternator.

8. The method of claim 6 , wherein the power supplied is further adjusted based on a temperature of the exhaust catalyst, the power decreased with an increase in the temperature of the catalyst.

9. The method of claim 6 , wherein the power supplied is further adjusted based on a flow of exhaust gas recirculation (EGR) from an engine exhaust to an engine intake, the power increased with an increase in EGR flow.

10. The method of claim 6 , wherein the electric turbocharger is operated in response to an actual charge pressure being lower than a target charge pressure, the target charge pressure based on an operator torque demand.

11. The method of claim 6 , wherein the electric turbocharger is operated in response to the lower than threshold temperature of the exhaust catalyst to increase exhaust air fuel ratio, the threshold temperature based on a light-off temperature of the catalyst.

12. The method of claim 6 , wherein the electric heater is operated to increase a temperature of the catalyst and then maintain the temperature of the catalyst above the light-off temperature.

13. A method for an engine, comprising: during a first condition, operating each of an electric turbocharger and an electric heater coupled to an exhaust catalyst by supplying power from a battery, a first power supplied to the electric heater being a function of a second power supplied to the electric turbocharger; and during a second condition, operating the electric turbocharger by supplying power from the battery while maintaining the electric heater inactive; wherein the first condition includes where the power supplied is directly proportionally increased with an increase in the energy supplied to the electric turbocharger, the electric turbocharger driven by an electric machine coupled to one of an exhaust turbine, an electric intake compressor, and a shaft connecting the exhaust turbine to an intake compressor.

14. The method of claim 13 , wherein the first condition includes a temperature of the catalyst being lower than a catalyst light-off temperature and the second condition includes the temperature of the catalyst being higher than the catalyst light-off temperature.

15. The method of claim 13 , wherein the first condition includes a cold-start when the electric turbocharger is operated to reduce an exhaust air fuel ratio to below a threshold.

16. The method of claim 13 , wherein the engine is coupled inside a hybrid vehicle, and wherein the battery is charged by regenerative braking.

17. The method of claim 13 , wherein the electric turbocharger includes an electric motor coupled to an exhaust turbine or an electric compressor, the electric motor capable of rotating the exhaust turbine or the electric compressor.

18. The method of claim 13 , wherein the second power increases with one or more of an increase in the first power and a decrease in the temperature of the catalyst.

Assignees

• Ford Global Tech Llc

Inventors

• Harmsen Jan
• Kemmerling Joerg

Classifications

• F01N2900/0602

  Electrical exhaust heater signals · CPC title

• F01N13/009

  having two or more separate purifying devices arranged in series · CPC title

• F01N2340/06

  Arrangement of the exhaust apparatus relative to the turbine of a turbocharger · CPC title

• F01N2900/104

  Battery status · CPC title

• F01N5/04

  the devices using kinetic energy · CPC title