Systems and methods for reducing vehicle emissions

Patent metadata

Field	Value
Publication number	US-10563605-B2
Application number	US-201815920226-A
Country	US
Kind code	B2
Filing date	Mar 13, 2018
Priority date	Mar 13, 2018
Publication date	Feb 18, 2020
Grant date	Feb 18, 2020

Abstract

Methods and systems are provided for reducing release of undesired emissions to atmosphere at a start event of an engine configured to propel a vehicle. In one example, a method comprises providing an alternative heat source and actively routing heat from the alternative heat source to a heated exhaust gas oxygen sensor for which a heating element configured to raise temperature of the sensor is known to be degraded. In this way, a desired air-fuel ratio may be attained during engine start events where the heating element for raising temperature of the sensor is degraded, which may thus reduce tail-pipe emissions which may otherwise be released in the absence of such mitigating action.

First claim

The invention claimed is:

1. A method, comprising:
reducing undesired emissions at a start event of an engine that propels a vehicle under conditions where a temperature of a heated exhaust gas oxygen sensor is below its desired operating temperature and where a heating element configured to heat the sensor is degraded, by providing an alternative heat source and actively routing heat from said source to the sensor to raise the temperature of the sensor to its desired operating temperature.

2. The method of claim 1 , wherein the start event of the engine comprises a cold-start event.

3. The method of claim 1 , wherein the start event of the engine comprises a start/stop event where the temperature of the sensor has decreased to below its desired operating temperature while the engine is not combusting air and fuel.

4. The method of claim 1 , wherein reducing undesired emissions includes reducing undesired emissions at the start event as compared to conditions where the heated exhaust gas oxygen sensor remains below its desired operating temperature for the start event.

5. The method of claim 1 , wherein actively routing heat from said source to the sensor includes one of rotating the engine unfueled in a forward or reverse direction or rotating an electric booster positioned in an intake of the engine in the forward or reverse direction, the forward or reverse direction for both rotating the engine and for rotating the electric booster selected based on a position of the sensor with respect to an emissions control device positioned in an exhaust system of the engine of the vehicle and the alternative heat source.

6. The method of claim 5 , further comprising rotating the engine unfueled in reverse, or rotating the electric booster in reverse, under conditions where the sensor is positioned upstream of the emissions control device and where the alternative heat source comprises a heater configured to heat the emissions control device;
rotating the engine unfueled in the forward direction or rotating the electric booster in the forward direction under conditions where the sensor is positioned upstream of the emissions control device and where the alternative heat source comprises one or more laser ignition devices configured to provide laser ignition energy to one or more cylinders of the engine; and
rotating the engine unfueled in the forward direction or rotating the electric booster in the forward direction under conditions where the sensor is positioned downstream of the emissions control device and where either or both of the heater configured to heat the emissions control device and/or the one or more laser ignition devices comprise the alternative heat source.

7. The method of claim 5 , wherein actively routing heat from said source to the sensor includes selecting whether to use the engine in the forward or reverse direction as compared to whether to use the electric booster in the forward or reverse direction, the selecting based on at least a charge state of an onboard energy storage device that powers a motor configured to rotate the engine and electric booster in the forward or reverse directions.

8. The method of claim 1 , further comprising controlling a position of an air intake throttle and/or an exhaust tuning valve, for the actively routing heat from said source to the sensor to raise the temperature of the sensor to its desired operating temperature.

9. A method, comprising:
at a start-event of an engine, responsive to detection of a degraded heating element of an oxygen sensor, operating a laser ignition source of the engine without combustion and spinning an electrically-driven intake air compressor to transport heated cylinder gas to the sensor.

10. The method of claim 9 , wherein the heating element is configured to raise a temperature of the sensor and wherein the heating element and the sensor are both positioned either upstream or downstream of an emissions control device positioned in an exhaust system of the engine.

11. The method of claim 9 , further comprising sealing a cylinder of the engine while operating the laser ignition source, where the cylinder receives laser ignition energy from the laser ignition source; and
unsealing the cylinder to transport heated cylinder gas to the sensor via spinning the electrically-driven intake air compressor.

12. The method of claim 11 , wherein unsealing the cylinder further comprises positioning the cylinder with both an intake valve and an exhaust valve coupled to the cylinder at least partially open.

13. The method of claim 11 , further comprising either stopping operating the laser ignition source upon unsealing the cylinder, or maintaining operating the laser ignition source upon unsealing the cylinder for transporting cylinder gas to the sensor.

14. The method of claim 9 , further comprising commanding open a wastegate positioned in a wastegate passage configured to route fluid flow around a turbine to transport heated cylinder gas to the sensor.

15. The method of claim 9 , further comprising commanding closed an exhaust gas recirculation valve positioned in an exhaust gas recirculation passage of the engine, to transport heated cylinder gas to the sensor.

16. The method of claim 9 , further comprising controlling a position of an air intake throttle and/or an exhaust tuning valve for transporting heated cylinder gas to the sensor.

Assignees

• Ford Global Tech Llc

Inventors

• Dudar Aed

Classifications

• F02D29/02

  peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers · CPC title

• F02P23/04

  Other physical ignition means, e.g. using laser rays · CPC title

• F02P5/1506

  with particular means during starting · CPC title

• F02D41/1495

  Detection of abnormalities in the air/fuel ratio feedback system · CPC title

• F02D41/065

  at hot start or restart (F02D41/067 takes precedence) · CPC title