Method for operating a fuel injection system of an internal combustion engine

Patent metadata

Field	Value
Publication number	US-9494102-B2
Application number	US-201213451094-A
Country	US
Kind code	B2
Filing date	Apr 19, 2012
Priority date	May 3, 2011
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

A method for operating a fuel injection system of an internal combustion engine is described in which pressurized fuel is provided in a pressure storage device and a fuel pressure prevailing in pressure storage device is regulated with the aid of a pressure regulation, during a first measuring interval at least one fuel withdrawal from the pressure storage device taking place, and during a second measuring interval no fuel withdrawal from the pressure storage device of this type taking place, and during the first and the second measuring intervals a performance quantity of the pressure regulation being ascertained in each case, and the fuel quantity withdrawn during the first measuring interval being ascertained for the at least one withdrawal from a difference of the ascertained performance quantities of the pressure regulation.

First claim

What is claimed is:

1. A method for operating a fuel injection system of an internal combustion engine, the method comprising:
providing pressurized fuel in a pressure storage device;
during a first measuring interval:
performing at least one controlled withdrawal of a predetermined quantity of fuel from the pressure storage device, thereby causing a controlled change in a fuel pressure prevailing in the pressure storage device;
a pressure sensor sensing, and outputting a signal corresponding to, a fuel pressure prevailing in the pressure storage device during the first measuring interval as a result of the controlled withdrawal of the predetermined quantity of fuel;
regulating, by a pressure regulation device, the fuel pressure prevailing in the pressure storage in response to the signal output by the pressure sensor during the first measuring interval; and
ascertaining a performance quantity characterizing the pressure regulation performed in response to the signal output by the pressure sensor during the first measuring interval;

during a second measuring interval, during which no controlled withdrawal of fuel from the pressure storage device is performed:
the pressure sensor sensing, and outputting a signal corresponding to, a fuel pressure prevailing in the pressure storage device during the second measuring interval;
regulating, by the pressure regulation device, the fuel pressure prevailing in the pressure storage in response to the signal output by the pressure sensor during the second measuring interval; and
ascertaining a performance quantity characterizing the pressure regulation performed in response to the signal output by the pressure sensor during the second measuring interval; and

determining a condition of the pressure sensor based on a difference between the performance quantity ascertained for the first measuring interval and the performance quantity ascertained for the second measuring interval.

2. The method of claim 1 , wherein the at least one fuel withdrawal is performed by activating a servo-valve of an injector of the internal combustion engine so that a control quantity of the fuel is withdrawn, at which the injector does not yet inject fuel into a combustion chamber of the internal combustion engine.

3. The method of claim 1 , wherein a servo-valve of an injector of the internal combustion engine is activated multiple times for withdrawing a control quantity during the first measuring interval.

4. The method of claim 1 , wherein the first and second measuring intervals are during an operating mode of the internal combustion engine in which usually there is no injection of fuel into a combustion chamber of the internal combustion engine.

5. The method of claim 1 , wherein:
the regulating of the fuel pressure includes regulating the fuel pressure in the pressure storage device to an identical pressure setpoint value, with the aid of the pressure regulation, in each of the first measuring interval and the second measuring interval;
the at least one fuel withdrawal is performed by activating the injector during the first measuring interval so that a control quantity of the fuel is withdrawn from the pressure storage device, the injector not yet injecting fuel into the combustion chamber;
the ascertaining of the performance quantity of the first measuring interval includes ascertaining, during the activation of the injector, a first value of the performance quantity of the pressure regulation, which is a manipulated variable of at least one of a pressure regulator and a fuel metering device; and
the determining of the condition of the pressure sensor includes comparing the difference to a difference that had been previously ascertained under comparable conditions and which is stored in a control/regulating unit of the internal combustion engine.

6. The method of claim 1 , wherein values of the performance quantity of the pressure regulation are ascertained in the first measuring interval and the second measuring interval both when the fuel injection system is in a new condition and when the fuel injection system is in an older condition, and the values ascertained in the first and second measuring intervals when the fuel injection system is in the older condition are compared to the values ascertained in the first and second measuring intervals when the fuel injection system was in the new condition, and the state of the pressure sensor is deduced from the comparison.

7. The method of claim 1 , wherein the performance quantity of the pressure regulation is ascertained at least one of at different fuel pressures, at different fuel temperatures, for different fuel types, and for different activation periods of one of an injector and an servo-valve of the injector.

8. A non-transitory computer readable medium having a computer program, which is executable by a processor, comprising:
a program code arrangement having program code for operating a fuel injection system of an internal combustion engine, by performing the following:
providing pressurized fuel in a pressure storage device; during a first measuring interval:
performing at least one controlled withdrawal of a predetermined quantity of fuel from the pressure storage device, thereby causing a controlled change in a fuel pressure prevailing in the pressure storage device;
obtaining from a pressure sensor a signal corresponding to a fuel pressure prevailing in the pressure storage device during the first measuring interval as a result of the controlled withdrawal of the predetermined quantity of fuel;
controlling a pressure regulation device to regulate the fuel pressure prevailing in the pressure storage in response to the signal output by the pressure sensor during the first measuring interval; and
ascertaining a performance quantity characterizing the pressure regulation performed in response to the signal output by the pressure sensor during the first measuring interval;

during a second measuring interval, during which no controlled withdrawal of fuel from the pressure storage device is performed:
obtaining from the pressure sensor a signal corresponding to, a fuel pressure prevailing in the pressure storage device during the second measuring interval;
controlling the pressure regulation device to regulate the fuel pressure prevailing in the pressure storage in response to the signal output by the pressure sensor during the second measuring interval; and
ascertaining a performance quantity characterizing the pressure regulation performed in response to the signal output by the pressure sensor during the second measuring interval; and

determining a condition of the pressure sensor based on a difference between the performance quantity ascertained for the first measuring interval and the performance quantity ascertained for the second measuring interval.

9. A control/regulating unit of an internal combustion engine, comprising:
a computer readable medium having a computer program, which is executable by a processor, including a program code arrangement having program code for operating a fuel injection system of an internal combustion engine, by performing the following:
providing pressurized fuel in a pressure storage device;
during a first measuring interval:
performing at least one controlled withdrawal of a predetermined quantity of fuel from the pressure storage device, thereby causing a controlled change in a fuel pressure prevailing in the pressure storage device;
obtaining from a pressure sensor a signal corresponding to a fuel pressure prevailing in the pressure storage device during the first measuring interval as a result of the controlled withdrawal of the predetermined quantity of fuel;
controlling a pressure regul

Assignees

• Strasser Markus
• Bosch Gmbh Robert

Inventors

• Strasser Markus

Classifications

• F02D41/2438

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• F02D41/3809 Primary

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• F02D2041/223

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