Systems and methods for improving engine emissions during starting

Patent metadata

Field	Value
Publication number	US-9644559-B2
Application number	US-201514806085-A
Country	US
Kind code	B2
Filing date	Jul 22, 2015
Priority date	Jul 22, 2015
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

Systems and methods for improving emissions of an internal combustion engine are presented. In one example, engine crankshaft acceleration is a basis for estimating engine air-fuel ratio during engine starting when output of an oxygen sensor may be unavailable. An actual engine air-fuel ratio may be adjusted in response to the estimated engine air-fuel ratio.

First claim

The invention claimed is:

1. An engine operating method, comprising:
receiving sensor data to a controller; and
adjusting an engine air-fuel ratio in response to a magnitude of a difference between a desired standard deviation of engine crankshaft acceleration and a determined standard deviation of engine crankshaft acceleration via the controller, the desired standard deviation of engine crankshaft acceleration based on a desired engine air-fuel ratio, the determined standard deviation of engine crankshaft acceleration based on the sensor data.

2. The method of claim 1 , where desired engine crankshaft acceleration is further estimated based on engine load, and where the desired engine air-fuel ratio is adjusted to be within an upper threshold engine air-fuel ratio and a lower threshold engine air-fuel ratio.

3. The method of claim 2 , where desired engine crankshaft acceleration is further estimated based on engine speed.

4. The method of claim 3 , where desired engine crankshaft acceleration is further estimated based on spark timing.

5. The method of claim 4 , where desired engine crankshaft acceleration is further estimated based on time since engine stop.

6. The method of claim 5 , where desired engine crankshaft acceleration is further estimated based on engine coolant temperature.

7. The method of claim 1 , where the engine air-fuel ratio is adjusted via adjusting opening timing of a fuel injector.

8. An engine operating method, comprising:
receiving sensor data to a controller; and
during an engine cold start where exhaust gas oxygen sensor data is unavailable, closed-loop adjusting an engine air-fuel ratio in response to a magnitude of a difference between a desired standard deviation of engine crankshaft acceleration and a determined standard deviation of engine crankshaft acceleration via the controller, the desired standard deviation of engine crankshaft acceleration based on a desired engine air-fuel ratio, the determined standard deviation of engine crankshaft acceleration based on the sensor data, the determined standard deviation of engine crankshaft acceleration approximated via two low pass filters.

9. The method of claim 8 , where the determined standard deviation of engine crankshaft acceleration is approximated via applying an absolute value to output of one of the two low pass filters.

10. The method of claim 8 , where the engine air-fuel ratio is adjusted via adjusting fuel injection timing.

11. The method of claim 8 , further comprising inputting the determined standard deviation of engine crankshaft acceleration into a proportional/integral/derivative controller and adjusting the engine air-fuel ratio in response to output of the proportional/integral/derivative controller.

12. The method of claim 8 , where the determined standard deviation of engine crankshaft acceleration is based on an engine position sensor.

13. The method of claim 8 , further comprising storing engine fuel adjustments based on the difference between the desired standard deviation of engine crankshaft acceleration and the determined standard deviation of engine crankshaft acceleration to memory.

14. An engine system, comprising:
an engine including a crankshaft position sensor;
an exhaust gas oxygen sensor coupled in an exhaust of the engine; and
a controller including executable instructions stored in non-transitory memory to adjust an air-fuel ratio of the engine in response to a magnitude of a standard deviation of engine crankshaft acceleration error during engine starting while output of the exhaust gas oxygen sensor is unavailable, the standard deviation of engine crankshaft acceleration error based on a desired engine air-fuel ratio and a determined standard deviation of engine crankshaft acceleration based on output of the crankshaft position sensor.

15. The engine system of claim 14 , further comprising additional instructions to adjust the air-fuel ratio via a fuel injector.

16. The engine system of claim 15 , further comprising additional instructions to determine engine crankshaft acceleration from the output of the crankshaft position sensor.

17. The engine system of claim 16 , further comprising additional instructions to filter the engine crankshaft acceleration.

18. The engine system of claim 17 , further comprising additional instructions to determine an absolute value of the filtered engine crankshaft acceleration.

19. The engine system of claim 18 , further comprising additional instructions to filter the absolute value of the filtered engine crankshaft acceleration.

20. The engine system of claim 14 , further comprising instructions to store engine fuel adjustments based on the difference between a desired standard deviation of engine crankshaft acceleration and the determined standard deviation of engine crankshaft acceleration to memory.

Assignees

• Ford Global Tech Llc

Inventors

• Pedro David
• Lehmen Allen
• Fried Marcus William
• Ranspach Paul Mahlon

Classifications

• F02D41/062 Primary

  for starting (F02D41/061 takes precedence) · CPC title

• F02D41/1497 Primary

  With detection of the mechanical response of the engine · CPC title

• F02D41/26

  using computer, e.g. microprocessor · CPC title

• F02D2200/02

  the parameters being related to the engine · CPC title

• F02D2200/101

  Engine speed · CPC title