Internal-combustion engines – Charge forming device – Including exhaust gas condition responsive means
Reexamination Certificate
2001-06-19
2003-12-09
Wolfe, Willis R. (Department: 3747)
Internal-combustion engines
Charge forming device
Including exhaust gas condition responsive means
C123S479000, C123S568160, C123S568220, C073S118040, C073S861610
Reexamination Certificate
active
06659095
ABSTRACT:
BACKGROUND OF INVENTION
1. Technical Field
The field of the invention relates to engine systems using pressure sensors. In particular, the field of the invention relates to systems that use a determination of barometric pressure.
2. Background of the Invention
Engine systems are known which utilize exhaust gas recirculation (EGR) to reduce engine emission and increase fuel economy. In one example, two pressure sensors are utilized not only to calculate EGR flow into the engine, but also to control air-fuel ratio. Typically, one sensor is coupled to the intake manifold and another is coupled in the EGR pathway between an EGR valve and an orifice. Such a system that provides dual use of sensors can offer cost advantages. Such a system is described in U.S. Pat. No. 6,138,504.
The inventors herein have recognized that there is a potential that the pressure sensors in such a system may degrade. In particular, if the intake manifold pressure sensor degrades, engine air-fuel ratio control may degrade thus affecting emissions. Further, if the pressure sensor coupled to the EGR system degrades, EGR flow control and flow estimation may degrade.
SUMMARY OF INVENTION
In one example, the above advantages over prior approaches are provided by a method for controlling an engine coupled to an exhaust gas recirculation system, the engine coupled to a first pressure sensor and the exhaust gas recirculation system coupled to second pressure sensor. The method comprises determining whether at least one of the first and second pressure sensor has degraded, and in response to said determination, discontinuing exhaust gas recirculation and calculating an engine air intake amount based on the other of said indicated at least one pressure sensor.
By utilizing the remaining operational pressure sensor when one pressure sensor has degraded, it is possible to accurately determine air entering the engine and therefore accurately control engine air-fuel ratio. This is particularly true since EGR has been discontinued. For example, the amount of EGR flowing into the engine affects the amount of fresh air inducted for a given manifold pressure. Thus, by discontinuing EGR, this error source is removed and accurate air determination is possible even with a reduced sensor set.
An advantage of the invention is improved engine control during sensor degradation.
Another advantage of the invention is that engine operation can be continued even when sensor degradation occurs.
REFERENCES:
patent: 4821194 (1989-04-01), Kawamura
patent: 5136517 (1992-08-01), Cullen et al.
patent: 5241940 (1993-09-01), Gates, Jr.
patent: 5613479 (1997-03-01), Gates et al.
patent: 5635633 (1997-06-01), Kadota
patent: 5698780 (1997-12-01), Mizutani et al.
patent: 5808189 (1998-09-01), Toyoda
patent: 5988149 (1999-11-01), Gates
patent: 6095123 (2000-08-01), Kotwicki et al.
patent: 6138504 (2000-10-01), Lewis et al.
patent: 6182644 (2001-02-01), Kotwicki et al.
patent: 6434474 (2002-08-01), Kotwicki et al.
patent: 6459985 (2002-10-01), Kotwicki et al.
patent: 2321317 (1998-07-01), None
patent: 10-18920 (1998-01-01), None
patent: 2001-182602 (2001-07-01), None
Bina Hossein
Gates Freeman Carter
Kotwicki Allan J.
Ford Global Technologies LLC
Kolisch & Hartwell, P.C.
Lippa Allan J.
Wolfe Willis R.
LandOfFree
Diagnosis system for upstream gauge sensor, downstream... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Diagnosis system for upstream gauge sensor, downstream..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Diagnosis system for upstream gauge sensor, downstream... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3123216