Fuel injection system of an internal combustion engine

Patent metadata

Field	Value
Publication number	US-9328708-B2
Application number	US-201113577973-A
Country	US
Kind code	B2
Filing date	Feb 3, 2011
Priority date	Mar 12, 2010
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

The invention relates to a fuel injection system of an internal combustion engine, comprising a presupply pump ( 1 ) and a downstream high-pressure pump ( 7 ), which is connected to a high-pressure accumulator ( 9 ) and wherein the high pressure accumulator ( 9 ) is operatively connected to at least one fuel injector ( 10 ). According to the invention, a fuel injection system is provided and a method for operating such a fuel system is described which avoids the disadvantage of a slow pressure build-up in the high-pressure accumulator ( 9 ) and rather allows a rapid start of the internal combustion engine. This is achieved in that the presupply pump ( 1 ) is designed to generate a delivery pressure by which a fuel injection by means of the fuel injector ( 10 ) is effected, at least in a defined operating state of the internal combustion engine. At the delivery pressure generated by the presupply pump ( 1 ), the fuel injector is prompted to open by a control device. A corresponding method for operating the fuel injection system provides for the presupply pump ( 1 ) to be operated in a starting operating mode until the internal combustion engine has been started, and after the internal combustion engine has been started to be operated in a presupply operating mode.

First claim

The invention claimed is:

1. A fuel injection system of an internal combustion engine, comprising a pre-supply pump ( 1 ), a suction valve ( 5 ), and a downstream high-pressure pump ( 7 ) which is connected to a high-pressure accumulator ( 9 ) and the high-pressure accumulator ( 9 ) is operatively connected to at least one fuel injector ( 10 ), characterized in that the fuel injection system further comprises a fuel metering device ( 4 ) between the pre-supply pump ( 1 ) and the high pressure pump ( 7 ), wherein the pre-supply pump ( 1 ) is designed to generate a delivery pressure at which a fuel injection is effected by means of the fuel injector ( 10 ), at least in a defined operating state of the internal combustion engine, and wherein the pre-supply pump ( 1 ) supplies fuel through the fuel metering device ( 4 ) and to the high-pressure pump ( 7 ) via the suction valve ( 5 ).

2. The fuel injection system as claimed in claim 1 , characterized in that the defined operating state is a starting process of the internal combustion engine.

3. The fuel injection system as claimed in claim 1 , characterized in that the pre-supply pump ( 1 ) generates a delivery pressure of up to 120 bar.

4. The fuel injection system as claimed in claim 1 , characterized in that the pre-supply pump ( 1 ) is a gear pump.

5. The fuel injection system as claimed in claim 1 , characterized in that the pre-supply pump ( 1 ) is operated electrically.

6. The fuel injection system as claimed in claim 1 , characterized in that a high-pressure pump working chamber ( 6 ) of the high-pressure pump ( 7 ) is connected to the suction valve ( 5 ) and to a nonreturn valve ( 8 ).

7. The fuel injection system as claimed in claim 1 , characterized in that the pre-supply pump ( 1 ) can be operated in a starting operating mode and in a pre-supply operating mode.

8. The fuel injection system as claimed in claim 7 , characterized in that the pre-supply pump ( 1 ) can be operated in the pre-supply operating mode after the internal combustion engine has been started.

9. A method for operating a fuel injection system of an internal combustion engine comprising a pre-supply pump ( 1 ), a suction valve ( 5 ), and a downstream high-pressure pump ( 7 ) which is connected to a high-pressure accumulator ( 9 ) which is operatively connected to a fuel injector ( 10 ), characterized in that the fuel injection system further comprises a fuel metering device ( 4 ) between the pre-supply pump ( 1 ) and the high pressure pump ( 7 ), wherein the pre-supply pump ( 1 ) is operated in a starting operating mode until the internal combustion engine has been started, in that during the starting operating mode a fuel injection is effected by the fuel injector ( 10 ) at the delivery pressure generated by the pre-supply pump ( 1 ) and in that the pre-supply pump ( 1 ) is operated in a pre-supply operating mode after the internal combustion engine has been started, and wherein, in both the starting operating mode and the pre-supply operating mode, the pre-supply pump supplies fuel through the fuel metering device ( 4 ) and to the high pressure pump ( 7 ) via the suction valve ( 5 ).

10. The method as claimed in claim 9 , characterized in that the pre-supply pump ( 1 ) can be operated in the starting operating mode in such a way that the delivery pressure of the pre-supply pump ( 1 ) corresponds to a minimum opening pressure of the fuel injector ( 10 ).

11. The method as claimed in claim 9 , characterized in that the pre-supply pump ( 1 ) can be adjusted to a delivery pressure of up to 120 bar in the starting operating mode and to a delivery pressure of up to 8 bar in the pre-supply operating mode.

12. The fuel injection system of claim 1 , wherein, in a starting operating mode, the fuel metering device ( 4 ) is operable to switch such that a control orifice of the fuel metering device ( 4 ) is open and an entire quantity of the fuel pumped by the pre-supply pump ( 1 ) is fed to the high-pressure pump ( 7 ), and wherein, in a normal operation mode, the fuel metering device ( 4 ) is operable to control a quantity of fuel supplied to the high-pressure pump ( 7 ) in dependence on the fuel pressure prevailing in the high-pressure accumulator ( 9 ).

13. The method of claim 9 , wherein, in the starting operating mode, the fuel metering device ( 4 ) is switched such that a control orifice of the fuel metering device ( 4 ) is open and an entire quantity of the fuel pumped by the pre-supply pump ( 1 ) is fed to the high-pressure pump ( 7 ), and wherein, in a normal operation mode, the fuel metering device ( 4 ) controls a quantity of fuel supplied to the high-pressure pump ( 7 ) in dependence on the fuel pressure prevailing in the high-pressure accumulator ( 9 ).

Assignees

• Boecking Friedrich
• Bosch Gmbh Robert

Inventors

• Boecking Friedrich

Classifications

• F02D41/3854

  with elements in the low pressure part, e.g. low pressure pump · CPC title

• F02D41/062

  for starting (F02D41/061 takes precedence) · CPC title

• F02M59/12 Primary

  having other positive-displacement pumping elements, e.g. rotary · CPC title

• F02M69/42

  using other means than variable fluid pressure, e.g. acting on the fuel metering device mechanically or electrically · CPC title

• F02M59/42 Primary

  for starting of engines {(supply of excess fuel F02M59/447)} · CPC title