Method and device for monitoring a high-pressure fuel system

Patent metadata

Field	Value
Publication number	US-9284904-B2
Application number	US-201013506000-A
Country	US
Kind code	B2
Filing date	Oct 12, 2010
Priority date	Nov 5, 2009
Publication date	Mar 15, 2016
Grant date	Mar 15, 2016

Abstract

A method for monitoring a fuel pressure in a fuel injection system of an internal combustion engine. A setpoint fuel pressure is initially set in the fuel injection system. Next, a first fuel injection and a subsequent second fuel injection are executed at a time interval shorter than a decay time of a pressure wave in the fuel injection system, triggerable by the first fuel injection. In an additional step, a monitored fuel injection quantity, which is injected via the second fuel injection, is ascertained. An action is executed if the monitored fuel injection quantity differs from a setpoint fuel injection quantity, which is predefinable for the setpoint fuel pressure, by more than a limiting value. The invention also relates to a computer program product for executing the method and to a device for monitoring a fuel pressure in a fuel injection system of an internal combustion engine.

First claim

What is claimed is:

1. A method for monitoring a fuel pressure in a fuel injection system of an internal combustion engine, the method comprising:
executing a first fuel injection and a subsequent second fuel injection in a monitoring time interval which is shorter than a decay time of a pressure wave in the fuel injection system triggerable by the first fuel injection;
setting a setpoint fuel pressure in response to an operating state of the fuel injection system at which there is a first actual fuel pressure in the fuel injection system, the setpoint fuel pressure being maintained after a change in the fuel injection system to a second actual fuel pressure;
setting a setpoint fuel injection quantity based on the setpoint fuel pressure;
ascertaining a monitored fuel injection quantity injected via the second fuel injection; and
outputting to a user of the internal combustion engine a warning of a defective pressure sensor when the monitored fuel injection quantity differs by more than a limiting value from the setpoint fuel injection quantity.

2. The method of claim 1 , wherein the setpoint fuel injection quantity specifies a total quantity of fuel delivered by the first fuel injection and the second fuel injection combined, and wherein an actual total fuel injection quantity injected as a whole via the first fuel injection and the second fuel injection is ascertained as the monitored fuel injection quantity.

3. The method of claim 1 , the method further comprising:
executing a calibration fuel injection to produce a calibration time interval before the first fuel injection which is longer than a decay time of a pressure wave in the fuel injection system triggerable by the calibration fuel injection;
ascertaining a calibration fuel injection quantity injected via the calibration fuel injection; and
establishing a triggering duration for at least one of the first fuel injection and the second fuel injection based on the calibration fuel injection quantity and the setpoint fuel injection quantity.

4. The method of claim 3 , wherein the execution of the calibration fuel injection and ascertainment of the calibration fuel injection quantity are executed repeatedly, and wherein a triggering time is ascertained for the respective subsequent calibration fuel injection based on the calibration fuel injection quantity and the setpoint fuel injection quantity.

5. The method of claim 1 , wherein the first fuel injection and the second fuel injection are executed repeatedly, the monitoring time interval being varied.

6. The method of claim 1 , wherein at least one of the first fuel injection and the second fuel injection is one of a preinjection and a postinjection, which does not contribute toward the rotational speed of the internal combustion engine.

7. The method of claim 1 , wherein the ascertainment of the monitored fuel injection quantity takes place based on a lambda sensor signal.

8. The method of claim 1 , wherein the ascertainment of the monitored fuel injection quantity occurs based on a signal of a tachometer or a torque meter.

9. A computer readable medium having a computer program, which is executable by a processor, comprising:
a program code arrangement having program code for monitoring a fuel pressure in a fuel injection system of an internal combustion engine, by performing the following:
executing a first fuel injection and a subsequent second fuel injection in a monitoring time interval which is shorter than a decay time of a pressure wave in the fuel injection system triggerable by the first fuel injection;
setting a setpoint fuel pressure in response to an operating state of the fuel injection system at which there is a first actual fuel pressure in the fuel injection system, the setpoint fuel pressure being maintained after a change in the fuel injection system to a second actual fuel pressure;
setting a setpoint fuel injection quantity based on the setpoint fuel pressure;
ascertaining a monitored fuel injection quantity injected via the second fuel injection; and
outputting to a user of the internal combustion engine a warning of a defective pressure sensor when the monitored fuel injection quantity differs by more than a limiting value from the setpoint fuel injection quantity.

10. A device for monitoring a fuel pressure in a fuel injection system of an internal combustion engine, comprising:
an injection control unit for executing a first fuel injection and a second fuel injection at a time interval which is shorter than a decay time of a pressure wave in the fuel injection system triggerable by the first fuel injection;
a fuel pressure controller for setting a setpoint fuel pressure in response to an operating state of the fuel injection system at which there is a first actual fuel pressure in the fuel injection system, the setpoint fuel pressure being maintained after a change in the fuel injection system to a second actual fuel pressure;
a fuel injection quantity presetting unit for setting a setpoint fuel injection quantity based on the setpoint fuel pressure;
a fuel injection quantity ascertaining unit for ascertaining a monitored fuel injection quantity injected via the second fuel injection; and
a warning unit for outputting to a user of the internal combustion engine a warning of a defective pressure sensor when the monitored fuel injection quantity differs by more than a limiting value from the setpoint fuel injection quantity.

11. The method of claim 1 , wherein the setpoint fuel pressure corresponds to a pressure at a fuel pressure storage device in the fuel injection system.

12. The method of claim 1 , wherein the setpoint fuel injection quantity is a quantity that will be delivered through the first and the second fuel injections if an actual fuel pressure in the fuel injection system is equal to the setpoint fuel pressure.

Assignees

• Topp Stephan
• Peck Rainer
• Zieher Rene
• Kriechbaum Christian
• Meyer-Salfeld Steffen
• Bosch Gmbh Robert

Inventors

• Topp Stephan
• Peck Rainer
• Zieher Rene
• Kriechbaum Christian
• Meyer-Salfeld Steffen

Classifications

• F02D41/222 Primary

  relating to the failure of sensors or parameter detection devices · CPC title

• F02D2041/228

  Warning displays · CPC title

• F02D2250/04

  Fuel pressure pulsation in common rails · CPC title

• Y02T10/44

  Cross-Sectional Technologies · mapped topic

• F02D41/22

  Safety or indicating devices for abnormal conditions {(in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809)} · CPC title