Drive device for fuel injection device

Patent metadata

Field	Value
Publication number	US-10704486-B2
Application number	US-201615546432-A
Country	US
Kind code	B2
Filing date	Feb 1, 2016
Priority date	Feb 27, 2015
Publication date	Jul 7, 2020
Grant date	Jul 7, 2020

Abstract

The purpose of the present invention is to provide a drive device that improves the precision of injection quantities by stabilizing the behavior of a valve body 214 under the condition that a valve body reaches a height position lower than a maximum height position and making the injection pulse width and the injection quantity gradient small. The present invention is a drive device for a fuel injection device for use in an internal combustion engine, wherein: the fuel injection device is provided with a valve body 214 that can open and close a fuel passage, a needle 202 that activates an opening and closing valve by transmitting power between itself and the valve body 214 , and an electromagnet that comprises a solenoid 205 and a fixed core 207 provided as drive means for the needle 202 , and a cylindrical nozzle holder 201 disposed on the outer peripheral side of the needle 202 ; and the drive device 150 controls a drive current flowing to the coil so as to decrease from the maximum drive current to a first drive current 610 that is lower than the maximum drive current before the valve body 214 reaches the maximum height position so that the valve body 214 reaches a height position lower than the maximum height position.

First claim

The invention claimed is:

1. A drive device for a fuel injection device including a valve body, a valve seat portion having a seat surface on which the valve body sits, a needle driving the valve body, and a coil driving the needle by a drive current flowing thereto, the drive device for the fuel injection device comprising:
a control unit configured to control a drive voltage or a drive current applied to the coil,
wherein the control unit is configured to control a height position of the valve body to be in a height position region lower than a maximum height position by decreasing the drive current flowing to the coil from a maximum drive current to a first drive current lower than the maximum drive current and changing a first drive current application time; and
wherein the control unit is configured to control the valve body so that the valve body reaches the maximum height position by decreasing the drive current flowing to the coil from the maximum drive current to the first drive current before the needle contacts the valve body, and then decreasing the drive current to a second drive current lower than the first drive current.

2. The drive device for the fuel injection device according to claim 1 ,
wherein the control unit is configured to keep the drive current above the first drive current during a period in which the control unit decreases the drive current from the maximum drive current while controlling the valve body so that the valve body reaches the maximum height position.

3. The drive device for the fuel injection device according to claim 1 ,
wherein the control unit is configured to control the height position of the valve body in the height position region lower than the maximum height position so that the height position becomes higher as the first drive current application time becomes longer.

4. The drive device for the fuel injection device according to claim 1 ,
wherein the control unit is configured to control a time in which the valve body is located at the maximum height position by changing a second drive current application time.

5. The drive device for the fuel injection device according to claim 1 ,
wherein the needle is disposed to have a gap with respect to the valve body in an axial direction while the valve body sits on the seat surface and contacts the valve body in the axial direction while the gap disappears and the valve body is pressed up in a direction opposite to the valve seat portion to control the fuel injection device.

6. The drive device for the fuel injection device according to claim 1 ,
wherein the control unit is configured to control the valve body so that the valve body reaches a height position lower than the maximum height position by decreasing the drive current flowing to the coil from the maximum drive current to the first drive current lower than the maximum drive current and then interrupting the drive current.

7. The drive device for the fuel injection device according to claim 1 ,
wherein the control unit is configured to control the first drive current application time by repeatedly allowing and not allowing the application of voltage to the coil so that the height position of the valve body at the height position region lower than the maximum height position is controlled.

8. The drive device for the fuel injection device according to claim 1 ,
wherein the control unit is configured to control a second drive current application time by repeatedly allowing and not allowing the application of voltage to the coil so that a time in which the valve body is located at the maximum height position is controlled.

9. The drive device for the fuel injection device according to claim 1 ,
wherein the control unit is configured to control the first drive current application time so that the first drive current application time becomes short when a pressure of a rail disposed at an upstream side of the fuel injection device is a set value or less and controls the first drive current application time so that the first drive current application time becomes long when the pressure of the rail is the set value or more.

10. The drive device for the fuel injection device according to claim 1 ,
wherein the control unit is configured to decrease a target value of the first drive current when battery voltage is continuously applied for a set time or a switching of a switch allowing and not allowing the application of the battery voltage is not performed for a set time.

11. The drive device for the fuel injection device according to claim 1 ,
wherein the control unit is configured to increase a target value of the first drive current when a pressure of a fuel pipe disposed at an upstream side of the fuel injection device is a set value or more.

12. A drive device for a fuel injection device including a valve body, a valve seat portion having a seat surface on which the valve body sits, a needle driving the valve body, a fixed piece disposed to face the needle, and a coil driving the needle by a drive current flowing thereto, the drive device for the fuel injection device comprising:
a control unit which is configured to control the needle so that the needle reaches a height position lower than a facing surface of the fixed piece by decreasing the drive current flowing to the coil from a maximum drive current to a first drive current lower than the maximum drive current, and
wherein the control unit is configured to control the needle so that the needle collides with the fixed piece by decreasing the drive current flowing to the coil from the maximum drive current to the first drive current before the needle collides with the fixed piece and then decreasing the drive current to a second drive current lower than the first drive current.

13. The drive device for the fuel injection device according to claim 12 ,
wherein the control unit is configured to control the height position of the needle at a height position region lower than the facing surface of the fixed piece by changing a first drive current application time.

14. The drive device for the fuel injection device according to claim 12 ,
wherein the control unit is configured to control a time in which the needle contacts the fixed piece by changing a second drive current application time.

15. The drive device for the fuel injection device according to claim 12 ,
wherein the control unit is configured to control the needle so that the needle reaches the height position lower than the facing surface of the fixed piece by decreasing the drive current flowing to the coil from the maximum drive current to the first drive current lower than the maximum drive current and then interrupting the drive current.

16. A drive device for a fuel injection device including a valve body, a valve seat portion having a seat surface on which the valve body sits, a needle driving the valve body, a fixed piece disposed to face the needle, and a coil driving the needle by a drive current flowing thereto, the drive device for the fuel injection device controlling an injection amount of the fuel injection device comprising:
a control unit which is configured to control the needle so that the needle reaches a height position lower than a facing surface of the fixed piece by decreasing the drive current flowing to the coil from a maximum drive current to a first drive current lower than the maximum drive current when fuel is injected in a first injection amount region; and
wherein the control unit is configured to control the needle so that the needle collides with the fixed piece by decreasing the drive cu

Assignees

• Hitachi Automotive Systems Ltd

Inventors

• Kusakabe Ryo
• IIZUKA Takatoshi
• Miyake Takao
• Sugaya Masashi
• Ogura Kiyotaka
• Yamaoka Shirou

Classifications

• F02M51/06

  Injectors peculiar thereto {with means directly operating the valve needle} · CPC title

• F02D2041/2041

  for controlling the current in the free-wheeling phase · CPC title

• F02M51/00

  Fuel-injection apparatus characterised by being operated electrically · CPC title

• F02D41/3064

  with special control during transition between modes · CPC title

• F02D2041/2051

  using voltage control · CPC title