Measuring and testing – Vehicle chassis – Steering
Reexamination Certificate
1997-11-14
2001-02-13
Dombroske, George (Department: 2855)
Measuring and testing
Vehicle chassis
Steering
C073S116070, C701S102000
Reexamination Certificate
active
06185996
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to techniques for diagnosing output power problems associated with internal combustion engines, and more specifically to systems for automating such techniques and for estimating actual engine output power over a desired engine RPM range.
BACKGROUND OF THE INVENTION
Manufacturers of internal combustion engines typically provide specifications indicating rated (target) power and/or torque outputs of the various manufactured engines over some specified engine speed range or ranges. At least for engines used in medium and heavy duty applications, such specifications are commonly provided as graphs or plots of engine output torque (wherein engine output torque is engine output power divided by engine speed) versus engine speed. An example of one such graph for a known Cummins M
11
engine is illustrated in
FIG. 1
, wherein engine output torque
5
(in Newton-Meters) is plotted over an engine speed range of between 1100 and 1800 RPM.
Within the medium and heavy duty industry, one of the most common complaints from owners of such vehicles is low engine power. Heretofore, a typical technique for investigating such complaints utilized a known fault tree search technique to check all known possible causes of a low engine power condition. However, such a technique does not provide any way to determine or otherwise estimate the actual output power of the suspect engine. In cases where no cause for low engine power is found, the fault tree search technique can, at best, provide an indication that the engine should have the rated power.
What is therefore needed is a system and method for diagnosing engine output power that quickly and efficiently narrows down possible causes for low engine power and further provides a simple and efficient technique for estimating actual engine output power over a desired engine speed range for comparison with rated engine output power specifications. Such a system would provide the equipment owner with improved diagnostic service by reducing misdiagnosis of engine output power related problems and by minimizing unnecessary parts replacement.
SUMMARY OF THE INVENTION
The foregoing shortcomings of the prior art are addressed by the present invention. In accordance with one aspect of the present invention, a method of diagnosing output power of an internal combustion engine having a number of cylinders, a fueling system responsive to fueling signals to fuel the engine and means for providing the fueling signals, comprises the steps of investigating existence of a low engine output power condition and performing the following steps only if the low engine output power condition exists; correcting relative compression values of each of the number of cylinders having a relative compression value below a predefined relative compression value, adjusting the fueling signals to balance a relative contribution to engine output power of each of the number of cylinders, and operating a vehicle carrying the engine along a drive path and estimating therefrom an actual engine output power over a desired engine speed range.
In accordance with another aspect of the present invention, a method of estimating actual output power of an internal combustion engine mounted in a vehicle and connected to a transmission having a number of selectable gear ratios, the engine having a fueling system responsive to fueling signals to fuel the engine, means for a providing the fueling signals and an engine speed sensor responsive to engine speed to provide an engine speed signal, and the vehicle having a vehicle speed sensor responsive to vehicle speed to provide a vehicle speed signal, comprises the steps of starting and warming up the engine, engaging the engine with a numerically low gear ratio of the transmission, accelerating the vehicle along a drive path and through a desired engine speed range while collecting one of engine speed and vehicle speed data, coasting the vehicle along the drive path and through a desired vehicle speed range corresponding to the desired engine speed range while collecting vehicle speed data, and processing the speed data collected during the accelerating and coasting steps and computing therefrom an estimate of actual engine output power over the desired engine speed range.
In accordance with a further aspect of the present invention, a method of estimating actual output power of an internal combustion engine mounted in a vehicle and connected to a transmission having a number of selectable gear ratios and a clutch for engaging and disengaging the gear ratios, the engine having a fueling system responsive to fueling signals to fuel the engine, means for a providing the fueling signals, an engine speed sensor responsive to engine speed to provide an engine speed signal and a vehicle speed sensor responsive to vehicle speed to provide a vehicle speed signal, comprises the steps of engaging the engine with a numerically low gear ratio of the transmission, accelerating the vehicle along a drive path and through a desired engine speed range under maximum engine fueling conditions while collecting one of engine speed and vehicle speed data, coasting the vehicle along the same drive path and through a desired vehicle speed range corresponding to the desired engine speed range with the clutch disengaged while collecting vehicle speed data, and processing the speed data collected during the accelerating and coasting steps and computing therefrom an estimate of actual engine output power over the desired engine speed range.
One object of the present invention is to provide a system and method for diagnosing output power of an internal combustion engine.
Another object of the present invention is to provide a system and method for estimating actual engine output power.
These and other objects of the present invention will become more apparent from the following description of the preferred embodiments.
REFERENCES:
patent: 2986032 (1961-05-01), Heyer
patent: 3592053 (1971-07-01), Lucia
patent: 3853002 (1974-12-01), Peck
patent: 3938378 (1976-02-01), Fineman et al.
patent: 3952586 (1976-04-01), Hanson et al.
patent: 4062232 (1977-12-01), Sutphin, Jr.
patent: 4295363 (1981-10-01), Buck et al.
patent: 4398259 (1983-08-01), Levine
patent: 4539841 (1985-09-01), Schroeder et al.
patent: 4546646 (1985-10-01), Takahashi
patent: 4548079 (1985-10-01), Klatt
patent: 4694687 (1987-09-01), Bonin et al.
patent: 4811223 (1989-03-01), Iwatsuki et al.
patent: 5041980 (1991-08-01), Maddock et al.
patent: 5087881 (1992-02-01), Peacock
patent: 5195038 (1993-03-01), Yagi et al.
patent: 5331560 (1994-07-01), Tamura
patent: 5365445 (1994-11-01), Takizawa
patent: 5446664 (1995-08-01), Vossen et al.
patent: 5452207 (1995-09-01), Hrovat et al.
patent: 5462031 (1995-10-01), Kai
patent: 5465208 (1995-11-01), Mochizuki et al.
patent: 5476072 (1995-12-01), Inventor
patent: 5501109 (1996-03-01), Naito et al.
patent: 5557519 (1996-09-01), Morita
patent: 5585553 (1996-12-01), Schricker
Bares Mark F.
Bradley Eric K.
He Chuan
Johnston Richard D.
Roettgen Leslie A.
Cummins Engine Company, Inc.
Dombroske George
Woodard Emhardt Naughton Moriarty & McNett
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