Method and Device for Operating a High-Pressure Accumulator Fuel Injection System for an Internal Combustion Engine

• US 20130206111A1
• Filed: 08/17/2011
• Published: 08/15/2013
• Est. Priority Date: 08/27/2010
• Status: Active Grant

• Current Assignee: Vitesco Technologies GmbH (Continental AG)
• Original Assignee: Continental Automotive GmbH (Continental AG)
• Inventors: Klesse, Christoph, Riepl, Hans, Anetsberger, Daniel, Ritsch, Tobias
• Granted Patent: US 9,410,498 B2
• Time in Patent Office: Days
• US Class Current: 123/478
• CPC Class Codes: F02D 2200/0602 Fuel pressure
• CPC Class Codes: F02D 2200/0606 Fuel temperature
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: F02D 41/2422 Selective use of one or more tables
• CPC Class Codes: F02D 41/38 of the high pressure type
• CPC Class Codes: F02D 41/3845 by controlling the flow into the common rail, e.g. the amount of fuel pumped
• CPC Class Codes: F02M 59/368 Pump inlet valves being closed when actuated
• CPC Class Codes: F02M 59/447 means specially adapted to limit fuel delivery or to supply excess of fuel temporarily, e.g. for starting of the engine combined with fuel pump regulating devices F02D
• CPC Class Codes: F02N 11/0814 comprising means for controlling automatic idle-start-stop
• CPC Class Codes: F02N 11/0818 Conditions for starting or stopping the engine or for deactivating the idle-start-stop mode
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A method is disclosed for operating a high-pressure accumulator fuel injection system for an internal combustion engine of a motor vehicle which has a stop-start automatic function by way of which the internal combustion engine can be switched off and restarted afterwards independent of the intervention of the driver of the motor vehicle, the fuel being conveyed to the high-pressure accumulator as needed by means of a high-pressure pump and the pressure of the fuel being adjusted on the pressure side by means of a pressure control valve which is electrically actuated and open when de- energized. According to the method, the supply with power of the pressure control valve is adapted to the prevailing pressure in the high-pressure accumulator during a stop phase within a stop-start cycle.

Claims

1. A method for operating a high-pressure accumulator fuel injection system for an internal combustion engine of a motor vehicle having an automatic stop/start function for deactivating and subsequently restarting the internal combustion engine independent of an intervention by the motor vehicle driver, in which fuel is fed to a high-pressure accumulator by a high-pressure pump, with at least one injector connected to the high-pressure accumulator for injecting fuel into at least one cylinder of the internal combustion engine, the method comprising:

setting a pressure of the fuel in the high-pressure accumulator using an electrically activated pressure control valve which is open in a currentless state, and

during a stop phase within a stop/start cycle, automatically adjusting the level of the electric current for supplying the pressure control valve to the prevailing pressure in the high-pressure accumulator.

2. The method of claim 1, comprising reducing the level of the electric current as a function of a pressure drop in the high-pressure accumulator.

3. The method of claim 2 comprising controlling the reduction of the level of the electric current to avoid overshooting a minimum injection release pressure of the at least one injector.

4. The method of claim 1 comprising measuring the pressure in the high-pressure accumulator using a pressure sensor, and using measured pressure values as input variables of a characteristic diagram in which associated values of the actuation current are stored as a function of the pressure.

5. The method of claim 1, comprising, when the internal combustion engine is deactivated,

(a) determining the pressure in the high-pressure accumulator and using said determined pressure as an input variable of a characteristic diagram in which a pressure reduction curve of the high-pressure accumulator fuel injector system plotted against the time is stored,

(b) after expiry of a predetermined time period, identifying from the characteristic diagram a value corresponding with the current time,

(c) using the identified pressure value as an input variable of a characteristic diagram in which associated values of the actuation current are stored as a function of the pressure, and

(d) repeating steps (b) and (c) at predetermined time intervals.

6. The method of claim 1, comprising determining the values of the electric current based at least on a determined temperature of the fuel.

7. A device for operating a high-pressure accumulator fuel injection system for an internal combustion engine of a motor vehicle having an automatic stop/start function for deactivating and subsequently restarting the internal combustion engine independent of intervention by the motor vehicle driver, in which fuel is fed to a high-pressure accumulator by a high-pressure pump, with at least one injector connected to the high-pressure accumulator for injecting fuel into at least one cylinder of the internal combustion engine, and

wherein the device is configured to:

set a pressure of the fuel in the high-pressure accumulator using an electrically activated pressure control valve which is open in a currentless state, and

during a stop phase within a stop/start cycle, automatically adjust the level of the electric current for supplying the pressure control valve to the prevailing pressure in the high-pressure accumulator.

8. The device of claim 7, configured to reduce the level of the electric current as a function of a pressure drop in the high-pressure accumulator.

9. The device of claim 8, configured to control the reduction of the level of the electric current to avoid overshooting a minimum injection release pressure of the at least one injector.

10. The device of claim 7, configured to measure the pressure in the high-pressure accumulator using a pressure sensor, and to use measured pressure values as input variables of a characteristic diagram in which associated values of the actuation current are stored as a function of the pressure.

11. The device of claim 7, configured to, when the internal combustion engine is deactivated,

(a) determine the pressure in the high-pressure accumulator and using said determined pressure as an input variable of a characteristic diagram in which a pressure reduction curve of the high-pressure accumulator fuel injector system plotted against the time is stored,

(b) after expiry of a predetermined time period, identify from the characteristic diagram a pressure value corresponding with the current time,

(c) use the identified pressure value as an input variable of a characteristic diagram in which associated values of the actuation current are stored as a function of the pressure, and

(d) repeat steps (b) and (c) at predetermined time intervals.

12. The device of claim 7, configured to determine the values of the electric current based at least on a determined temperature of the fuel.

13. An internal combustion engine of a motor vehicle, comprising:

at least one cylinder,

a high-pressure accumulator fuel injection system having a high-pressure accumulator, a high-pressure pump configured to feed fuel to the high-pressure accumulator, and at least one injector connected for injecting fuel into the at least one cylinder,

a control system for an automatic stop/start function for deactivating and subsequently restarting the internal combustion engine independent of intervention by the motor vehicle driver, and

a pressure control device is configured to;

set a pressure of the fuel in the high-pressure accumulator using an electrically activated pressure control valve which is open in a currentless state, and

during a stop phase within a stop/start cycle, automatically adjust the level of the electric current for supplying the pressure control valve to the prevailing pressure in the high-pressure accumulator.

14. The internal combustion engine of claim 13, wherein the pressure control device is configured to reduce the level of the electric current as a function of a pressure drop in the high-pressure accumulator.

15. The internal combustion engine of claim 14, wherein the pressure control device is configured to control the reduction of the level of the electric current to avoid overshooting a minimum injection release pressure of the at least one injector.

16. The internal combustion engine of claim 13, wherein the pressure control device is configured to measure the pressure in the high-pressure accumulator using a pressure sensor, and to use measured pressure values as input variables of a characteristic diagram in which associated values of the actuation current are stored as a function of the pressure.

17. The internal combustion engine of claim 13, wherein the pressure control device is configured to, when the internal combustion engine is deactivated,

(a) determine the pressure in the high-pressure accumulator and using said determined pressure as an input variable of a characteristic diagram in which a pressure reduction curve of the high-pressure accumulator fuel injector system plotted against the time is stored,

(b) after expiry of a predetermined time period, identify from the characteristic diagram a pressure value corresponding with the current time,

(c) use the identified pressure value as an input variable of a characteristic diagram in which associated values of the actuation current are stored as a function of the pressure, and

(d) repeat steps (b) and (c) at predetermined time intervals.

18. The internal combustion engine of claim 13, wherein the pressure control device is configured to determine the values of the electric current based at least on a determined temperature of the fuel.