Oxygen depletion sensing for a remote starting vehicle

• US 20060068973A1
• Filed: 09/27/2004
• Published: 03/30/2006
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Brehob, Diana D., Kappauf, Todd
• Granted Patent: US 7,167,791 B2
• Time in Patent Office: Days
• US Class Current: 477/107
• CPC Class Codes: B60R 25/042 operating on the fuel supply
• CPC Class Codes: B60R 25/209 Remote starting of engine
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: F02D 41/1454 the characteristics being an oxygen content or concentration or the air-fuel ratio
• CPC Class Codes: F02D 41/1458 with determination means using an estimation
• CPC Class Codes: F02D 41/187 using a hot wire flow sensor
• CPC Class Codes: F02N 11/0807 Remote means
• CPC Class Codes: F02N 11/10 Safety devices F02N11/08 takes precedence

Abstract

Automotive vehicles are increasingly being equipped with remote starting devices. If the vehicle is within a space which is very well sealed, it is possible that the concentration of the exhaust gases may exceed desirable levels. A method and system are disclosed in which a mass-based determination of air/fuel ratio is compared with the air/fuel ratio being maintained by the exhaust gas oxygen sensor. When the air/fuel ratio based on a mass measurement deviates from the air/fuel ratio based on the exhaust gas oxygen sensor by more than a threshold difference, the remotely started vehicle is turned off.

Claims

1. A method to control an internal combustion engine, the engine being adapted for remote starting, comprising:

determining a measured air/fuel ratio based on fuel flow and air flow, said fuel flow and said air flow being supplied to the engine;

computing an error based on said first air/fuel ratio and a stoichiometric air/fuel ratio; and

ceasing engine combustion when said error exceeds a threshold and when it is determined that the engine has been started remotely.

2. The method of claim 1 wherein said measured air/fuel ratio is determined from a fuel pulse width commanded to fuel injectors coupled to said engine and a determined mass air flow delivered to said engine.

3. The method of claim 2 wherein said mass air flow is based on a signal from a mass air flow sensor coupled to an engine intake.

4. The method of claim 2 wherein said mass air flow is based on engine rpm and intake manifold absolute pressure, said intake manifold being coupled to the internal combustion engine.

5. The method of claim 1 wherein said error is computed as said measured air/fuel ratio minus said stoichiometric air/fuel ratio.

6. The method of claim 1, further comprising:

allowing said engine combustion to continue when the engine is under operator control.

7. The method of claim 1, further comprising:

determining whether the engine is under operator control wherein said ceasing of engine combustion occurs based on whether the engine is under other than operator control.

8. The method of claim 1 wherein said combustion cessation comprises shutting off fuel injectors, said fuel injectors being coupled to the internal combustion engine.

9. The method of claim 1 wherein the engine is installed in a vehicle and said remote starting comprises:

an operator-activated actuator adapted to send a start signal in response to an operator command for said remote start; and

a sensor coupled to said vehicle which is adapted to accept said start signal from said operator-activated actuator.

10. The method of claim 1, further comprising:

determining that the engine is being operated in a closed-loop, air/fuel ratio control mode, said mode being based on a signal from an exhaust gas oxygen sensor, said exhaust gas oxygen sensor being coupled to an engine exhaust;

initiating said error computation based on said engine operation being in closed-loop mode.

11. The method of claim 1 wherein said stoichiometric air/fuel ratio is based on fuel being used in the engine.

12. The method of claim 1 wherein said stoichiometric air/fuel ratio is 14.6 when gasoline is being supplied to the engine.

13. A vehicle system, comprising:

an internal combustion engine, said engine being adapted to respond to a signal to start independently of an operator of the vehicle being inside the vehicle;

fuel injectors coupled to said engine;

an exhaust gas oxygen sensor coupled to an exhaust of said engine;

an electronic control unit coupled to said engine, said exhaust gas oxygen sensor, and said fuel injectors, when said engine has been started independent of an operator, said electronic control unit determining a measured air/fuel ratio based on a fuel pulse width commanded to said fuel injectors and causing operation of the engine to cease when an error based on said measured air/fuel ratio exceeds from a stoichiometric air/fuel ratio by-a threshold error.

14. The vehicle system of claim 13, further comprising:

a sensor proximate to the engine and electronically coupled to the electronic control unit from which engine rpm can be determined;

a manifold pressure sensor coupled to an engine intake wherein said second air/fuel ratio is further based on said engine rpm and said manifold pressure to provide an mass air flow estimate.

15. The vehicle system of claim 13, further comprising:

a sensor in an intake of the engine and lectronically coupled to the electronic control unit, said sensor providing a signal from which a mass air flow can be estimated wherein said second air/fuel ratio is further based on said mass air flow.

16. The vehicle system of claim 13 wherein said stoichiometric air/fuel ratio depends on the fuel supplied to said engine.

17. The vehicle system of claim 13 wherein said operator intervention is based on a door of said vehicle having been opened.

18. The vehicle system of claim 13 wherein said operator intervention is based on an operator inserting a key into an ignition switch coupled to the vehicle.

19. The vehicle system of claim 13 wherein said operator intervention is based on an operator turning a key inserted into an ignition switch coupled to the vehicle.

20. The vehicle system of claim 13, further comprising:

an automatic transmission coupled to said engine; and

a shift lever coupled to said automatic transmission wherein said operator intervention is based on an operator moving a shift lever out of a park position.

21. The vehicle system of claim 13, further comprising:

a manual transmission coupled to said engine via a clutch; and

a clutch pedal coupled to said clutch wherein said operator intervention is based on an operator depressing said clutch pedal.

22. The vehicle system of claim 13, further comprising:

a manual transmission coupled to said engine via a clutch; and

a gear shift mechanism coupled to said manual transmission wherein said operator intervention is based on an operator changing gears using said gear shift mechanism.

23. A method to control an internal combustion engine installed into a vehicle, the engine being adapted for remote starting, comprising:

determining a measured air/fuel ratio based on fuel flow and air flow to the engine;

computing an error based on said first air/fuel ratio and a stoichiometric air/fuel ratio; and

ceasing engine combustion when said error exceeds a threshold.

24. The method of claim 23 wherein said engine combustion cessation occurs only when an operator of the vehicle has not intervened.

25. The method of claim 23 wherein said operator intervention comprises at least one of:

opening a door of the vehicle, inserting a key into an ignition switch coupled to the vehicle, turning a key inserted into an ignition switch coupled to the vehicle, and moving a shift lever out of a park position, said shift lever being coupled to an automatic transmission, said automatic transmission being coupled to the engine.

26. The method of claim 23 wherein said engine combustion cessation comprises stopping fuel delivery by fuel injectors coupled to the engine.

27. The method of claim 23 wherein said threshold is based on maintaining an acceptable concentration of exhaust gases in an engine intake or less.

28. The method of claim 23, further comprising:

computing a minimum delay time before restart is allowed, said minimum delay time being based on a time history of measured air/fuel ratio prior to said engine combustion cessation.

29. The method of claim 28, further comprising:

comparing said minimum delay time with an actual delay time, said actual delay time being the time elapsed since said engine was shutdown; and

allowing engine restart when said actual delay exceeds said minimum delay.

30. The method of claim 28 wherein said minimum delay time is based on a time rate of change of said measured air/fuel ratio prior to said engine cessation.

31. The method of claim 23 wherein said engine cessation occurs only when the engine has been remotely started.

32. The method of claim 23, further comprising:

setting a code in an engine control unit coupled to the engine when engine combustion cessation has occurred.

33. The method of claim 32, further comprising:

allowing said engine to restart upon operator request; and

when said code has been set, performing;

said determining a measured air/fuel ratio based on fuel flow and air flow to the engine;

said computing an error based on said first air/fuel ratio and a stoichiometric air/fuel ratio; and

said ceasing engine combustion when said error exceeds a threshold.