Measuring and testing – Simulating operating condition – Marine
Patent
1997-04-21
1999-08-31
Chilcot, Richard
Measuring and testing
Simulating operating condition
Marine
G01M 1500
Patent
active
059455969
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention, a continuation of PCT/DE96/00737 dated Apr. 27, 1996, relates to a method and a device for monitoring a fuel-metering system.
BACKGROUND INFORMATION
A method and device of this type are disclosed by U.S. Pat. No. 5,241,933. It describes a method and a device for monitoring a high-pressure circuit when working with a common-rail system. In the case of the device it describes, the pressure prevailing in the rail is regulated. If the manipulated variable of the pressure control loop lies outside of a specifiable range, the device recognizes the existence of an error.
In addition, devices are known, where the existence of an error is inferred on the basis of the pressure prevailing in the rail. The pressure is thereby compared to lower and upper limiting values, and the existence of errors is recognized when the pressure lies outside of the specified range of values.
The drawback of these arrangements is that an error is first recognized in response to a substantial pressure drop.
SUMMARY OF THE INVENTION
Given a device and a method for monitoring a fuel-metering system, the object of the present invention is to be able recognize the existence of errors in the most reliable and simple manner possible.
The method and device according to the present invention make it possible for errors in the metering system to be recognized reliably and simply. In particular, it is possible to reliably verify defective injectors in common-rail systems.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a block diagram of the device according to one embodiment of the present invention.
FIG. 2a illustrates signals from a structure-borne noise sensor plotted over time according to one embodiment of the present invention.
FIG. 2b illustrates signals from a structure-borne noise sensor plotted over time, given a faulty injector in the second cylinder, according to one embodiment of the present invention.
FIG. 2c illustrates signals from a structure-borne noise sensor plotted over time when no fuel is injected into the second cylinder, according to one embodiment of the present invention.
FIG. 3 illustrates a flow chart of the method according to one embodiment of the present invention.
FIG. 4 illustrates a schematic representation of an internal combustion engine incorporating one embodiment of the present invention.
FIG. 5 illustrates a block diagram of the signal evaluation method according to one embodiment of the present invention.
FIG. 6a illustrates the cylinder pressure plotted over time according to one embodiment of the present invention.
FIG. 6b illustrates the output from a needle motion sensor plotted over time according to one embodiment of the present invention.
FIG. 6c illustrates the output from a knock sensor plotted over time according to one embodiment of the present invention.
FIG. 6d illustrates the output signal from a band pass filter plotted over time according to one embodiment of the present invention.
FIG. 6e illustrates the output signal from a band pass filter plotted over time according to one embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The device according to the present invention will now be elucidated based on the example of a self-ignition internal combustion engine, in which the fuel metering is controlled by means of a solenoid valve. The specific embodiment of the present invention shown in FIG. 1 relates to what is known as a common-rail system. However, the procedure in accordance with the present invention is not limited to these systems. It can be employed in all systems where such a fuel metering is possible.
Element 100 denotes an internal combustion engine, which is supplied with fresh air via an intake line 105 and which emits exhaust gas via an exhaust pipe 110.
The illustrated internal combustion engine is a four-cylinder internal combustion engine. Assigned to each cylinder of the internal combustion engine are injectors 120, 121, 122 and 123. Fuel is metered to the injectors via solenoid valve
REFERENCES:
patent: 5533477 (1996-07-01), Weigl
patent: 5731515 (1998-03-01), Tominaga et al.
patent: 5770796 (1998-06-01), Sakamoto et al.
Biester Jurgen
Bronkal Bernhard
Burkel Rainer
Eyberg Wilhelm
Fink Lutz-Martin
Chilcot Richard
McCall Eric S.
Robert & Bosch GmbH
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