Operating a fuel injector having a hydraulic stop

Patent metadata

Field	Value
Publication number	US-10648420-B2
Application number	US-201716338924-A
Country	US
Kind code	B2
Filing date	Sep 27, 2017
Priority date	Oct 12, 2016
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

Various embodiments include a method for operating a fuel injector with a solenoid drive having a hydraulic stop at a predetermined fuel pressure comprising: applying a first current profile to the solenoid including a first holding current value prespecifying the current flowing during a holding phase; determining a resulting first flux; determining a first force based on the first flux corresponding to a hydraulic force exerted on the armature by fuel; determining a deviation between the first force and an optimal force corresponding to the predetermined fuel pressure; determining a second holding current based on the first holding current and the determined deviation; and applying a second current profile to carry out a second injection process using the second holding current value to apply a hydraulic force on the armature by the fuel adapted to the optimal force value.

First claim

What is claimed is:

1. A method for operating a fuel injector having a hydraulic stop at a predetermined fuel pressure, wherein the fuel injector has a solenoid drive having a solenoid and a movable armature, the method comprising:
applying a first current profile to the solenoid drive to carry out a first injection process, wherein the first current profile includes a first holding current value prespecifying a current level of the current flowing through the solenoid during a holding phase;
determining a first flux value corresponding to a magnetic flux in the holding phase;
determining a first force value based on the first flux value, wherein the first force value corresponds to a hydraulic force exerted on the armature by fuel in the holding phase;
determining a deviation between the first force value and an optimal force value which corresponds to the predetermined fuel pressure;
determining a second holding current value based on the first holding current value and the determined deviation; and
applying a second current profile to the solenoid drive to carry out a second injection process using the second holding current value to apply a hydraulic force on the armature by the fuel adapted to the optimal force value.

2. The method as claimed in claim 1 , further comprising determining the optimal force value corresponding to the predetermined fuel pressure based on a stored relationship between fuel pressure, hydraulic force, and injector throughflow.

3. The method as claimed in claim 1 , further comprising determining the first flux value based on a time profile of the electrical voltage across the solenoid, a time profile of the current level of the current flowing through the solenoid, and the electrical resistance of the solenoid.

4. The method as claimed in claim 1 , wherein the second holding current value is greater than the first holding current value when the first force value is lower than the optimal force value, and wherein the second holding current value is lower than the first holding current value when the first force value is greater than the optimal force value.

5. The method as claimed in claim 1 , wherein:
the first current profile has a first peak current value and the second current profile has a second peak current value;
the second peak current value is determined based on the first peak current value and the determined deviation such that the process of adapting the hydraulic force which is exerted on the armature by the fuel to the optimal force value is assisted.

6. The method as claimed in claim 1 , further comprising:
determining a second flux value which corresponds to the magnetic flux in the holding phase;
determining a second force value based on the second flux value, wherein the second force value corresponds to a hydraulic force which is exerted on the armature by fuel in the holding phase;
determining a deviation between the second force value and the optimal force value; and
applying a third current profile to the solenoid drive to carry out a third injection process, wherein the third current profile has a third holding current value determined based on the second holding current value and the determined deviation in such a way that the hydraulic force which is exerted on the armature by the fuel in the holding phase is adapted to the optimal force value.

7. An engine controller for a vehicle, the engine controller comprising:
a processor; and
a memory storing a set of instructions, the set of instructions, when loaded and executed by the processor, causing the processor to:
apply a first current profile to a solenoid drive of a fuel injector to carry out a first injection process, wherein the first current profile includes a first holding current value prespecifying a current level of the current flowing through the solenoid during a holding phase;
determine a first flux value corresponding to a magnetic flux in the holding phase;
determine a first force value based on the first flux value, wherein the first force value corresponds to a hydraulic force exerted on the armature by fuel in the holding phase;
determine a deviation between the first force value and an optimal force value which corresponds to the predetermined fuel pressure;
determine a second holding current value based on the first holding current value and the determined deviation; and
apply a second current profile to the solenoid drive to carry out a second injection process using the second holding current value to apply a hydraulic force on the armature by the fuel adapted to the optimal force value.

8. A computer program stored on a non-transitory medium, the computer program, when executed by a processor, causing the processor to:
apply a first current profile to a solenoid drive of a fuel injector to carry out a first injection process, wherein the first current profile includes a first holding current value prespecifying a current level of the current flowing through the solenoid during a holding phase;
determine a first flux value corresponding to a magnetic flux in the holding phase;
determine a first force value based on the first flux value, wherein the first force value corresponds to a hydraulic force exerted on the armature by fuel in the holding phase;
determine a deviation between the first force value and an optimal force value which corresponds to the predetermined fuel pressure;
determine a second holding current value based on the first holding current value and the determined deviation; and
apply a second current profile to the solenoid drive to carry out a second injection process using the second holding current value to apply a hydraulic force on the armature by the fuel adapted to the optimal force value.

Assignees

• Cpt Group Gmbh
• Vitesco Tech Gmbh

Inventors

• Stutika Markus
• Rösel Gerd

Classifications

• F02D41/20 Primary

  Output circuits, e.g. for controlling currents in command coils · CPC title

• F02D2041/2058

  using information of the actual current value · CPC title

• F02D41/2467

  for injectors · CPC title

• F02D2041/227

  Limping Home, i.e. taking specific engine control measures at abnormal conditions · CPC title

• F02M45/12

  providing a continuous {cyclic} delivery with variable pressure · CPC title