High-pressure fuel supply device for internal combustion engine

Patent metadata

Field	Value
Publication number	US-10557445-B2
Application number	US-201615536689-A
Country	US
Kind code	B2
Filing date	Jan 12, 2016
Priority date	Jan 21, 2015
Publication date	Feb 11, 2020
Grant date	Feb 11, 2020

Abstract

Provided is a high-pressure fuel supply device for an internal combustion engine, said device being capable of suppressing noise from collisions of a plunger rod and an air intake valve. A high-pressure fuel pump 108 comprises an intake valve, a plunger rod that is formed as a separate element from the intake valve, an elastic member that biases the plunger rod in the valve-opening direction of the intake valve, and a solenoid that draws the plunger rod in the valve-closing direction of the intake valve when supplied with electricity. A control device 101 has a first control unit that applies a first current to the solenoid in order to close the intake valve, and a second control unit that applies a second current to the solenoid before the plunger rod collides with the intake valve due to the biasing force of the elastic member.

First claim

The invention claimed is:

1. A high-pressure fuel supply device for an internal combustion engine comprising:
a high-pressure fuel pump including an intake valve, a plunger rod which is formed as a separate element from the intake valve, an elastic member which biases the plunger rod in a valve-opening direction of the intake valve, and a solenoid which draws the plunger rod in a valve-closing direction of the intake valve when supplied with electricity; and
a control device including
a first control unit which applies a first current to the solenoid during a pumping cycle to close the intake valve, and
a second control unit which applies a second current to the solenoid during the pumping cycle: i) at a predetermined time that is after a time at which the first current reaches a current value of zero, and ii) before the plunger rod collides with the intake valve during the pumping cycle due to biasing force of the elastic member, wherein
a current value of the second current is smaller than a maximum value of the first current, and
the entire second current is supplied before a piston plunger, which pressurizes a fuel, reaches a top dead center position during the pumping cycle.

2. The high-pressure fuel supply device for an internal combustion engine according to claim 1 , wherein the control device further comprises a third control unit which cuts off the first current and which sets a current of the solenoid to zero.

3. The high-pressure fuel supply device for an internal combustion engine according to claim 1 ,
wherein the control device further comprises a position detecting unit which detects a position of the plunger rod, and
the second control unit applies the second current to the solenoid before a position of the plunger rod reaches a collision position indicating a position where the plunger rod and the intake valve collide with each other.

4. The high-pressure fuel supply device for an internal combustion engine according to claim 3 , wherein the position detecting unit detects the position of the plunger rod based on a measured value of a current or a voltage of the solenoid.

5. The high-pressure fuel supply device for an internal combustion engine according to claim 3 ,
wherein the control device further comprises an estimating unit which detects an inflection point from a measured value of a voltage of the solenoid with a lapse of time after the third control unit cuts off the first current and which estimates the position of the plunger rod at a time of the inflection point as the collision position, and
the second control unit determines timing of applying the second current by using the estimated collision position.

6. The high-pressure fuel supply device for an internal combustion engine according to claim 5 , wherein the second control unit determines timing of applying the second current by using a statistical value of the estimated collision position.

7. The high-pressure fuel supply device for an internal combustion engine according to claim 1 , wherein the second control unit decreases the second current as a temperature correlated with a speed of the intake valve increases.

8. The high-pressure fuel supply device for an internal combustion engine according to claim 7 , wherein the temperature is a temperature of cooling water, a temperature of lubricating oil, or a temperature of fuel.

9. The high-pressure fuel supply device for an internal combustion engine according to claim 1 , wherein the second control unit increases the second current as fuel pressure increases.

10. The high-pressure fuel supply device for an internal combustion engine according to claim 1 , wherein the second control unit increases the second current as an engine rotating speed increases.

Assignees

• Hitachi Automotive Systems Ltd

Inventors

• Arihara Yoshinobu
• Okamoto Takashi

Classifications

• F02M59/368 Primary

  Pump inlet valves being closed when actuated · CPC title

• F02M2200/09

  Fuel-injection apparatus having means for reducing noise · CPC title

• F02M63/0031

  characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details · CPC title

• F02D41/20

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

• F02D41/3845

  by controlling the flow into the common rail, e.g. the amount of fuel pumped · CPC title