Control apparatus for fuel injection valve and method thereof

Patent metadata

Field	Value
Publication number	US-9926879-B2
Application number	US-201414890332-A
Country	US
Kind code	B2
Filing date	May 7, 2014
Priority date	May 10, 2013
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

Abstract

An electronic control unit that calculates an injection standby period, which is a period from an energization start point of the solenoid to a point at which the fuel injection valve opens, and adjusts an energization period of the solenoid in accordance with the calculated injection standby period. The electronic control unit of the control apparatus for a fuel injection valve then measures a reference fall detection period, which is a period from the energization start point to a reference fall detection point, and sets the injection standby period to be longer as the reference fall detection period is longer. Here, the reference fall detection point is a point at which the excitation current detected by the current detection circuit falls below a reference current value, which is smaller than a peak current value, while the excitation current decreases after reaching the peak current value.

First claim

What is claimed is:

1. A control apparatus for a fuel injection valve, the control apparatus comprising:
a drive control unit that controls an opening and closing operation of the fuel injection valve by causing an excitation current to flow in a solenoid of the fuel injection valve;
a current detection circuit that detects the excitation current flowing in the solenoid; and
an electronic control unit programmed to:
(a) calculate an injection standby period that is a period from an energization start point of the solenoid to a point at which the fuel injection valve opens;
(b) adjust an energization period of the solenoid in accordance with the injection standby period;
(c) measure a reference fall detection period that is a period from the energization start point to a reference fall detection point, the reference fall detection point being a point at which the excitation current detected by the current detection circuit falls below a reference current value that is smaller than a peak current value, while the excitation current decreases after the excitation current reaches the peak current value; and
(d) set the injection standby period to be longer as the reference fall detection period is longer,
wherein the peak current value is a value that is set as a current value at which the fuel junction valve opens reliably.

2. The control apparatus for a fuel injection valve according to claim 1 , wherein the electronic control unit is programmed to measure a reference rise detection period that is a period from the energization start point to a reference rise detection point, and calculate a reference rise calculation period by multiplying a reference conversion coefficient by the reference fall detection period,
the reference rise detection point being a point at which the excitation current detected by the current detection circuit exceeds the reference current value while the excitation current increases toward the peak current value, and the reference rise calculation period being a calculated value of the period from the energization start point to the reference rise detection point,
the electronic control unit is programmed to increase a reference fall variation ratio steadily as a reference rise variation ratio increases, the reference rise variation ratio is a quotient obtained by dividing the reference rise calculation period by the reference rise detection period, and
the electronic control unit is programmed to calculate a reference fall calculation period by multiplying the reference fall variation ratio by the reference fall detection period, and set the injection standby period to be longer as the reference fall calculation period is longer.

3. The control apparatus for a fuel injection valve according to claim 2 , wherein the electronic control unit is programmed to measure a learned rise detection period that is a period from the energization start point to a learned rise detection point, the learned rise detection point being a point at which the excitation current detected by the current detection circuit equals or exceeds a learning current value that is smaller than the reference current value, while the excitation current increases toward the peak current value,
the electronic control unit is programmed to calculate a learned rise calculation period that is a calculated value of the period from the energization start point to the learned rise detection point, by multiplying a learning conversion coefficient by the reference fall calculation period,
the electronic control unit is programmed to calculate a variation ratio learned value by dividing the learned rise calculation period by the learned rise detection period, and
the electronic control unit is programmed to measure the learned rise detection period during a fuel injection, and set the injection standby period to be longer as a product obtained by multiplying the variation ratio learned value by the learned rise detection period increases.

4. The control apparatus for a fuel injection valve according to claim 3 , wherein the electronic control unit is programmed not to calculate the variation ratio learned value when energization of the fuel injection valve is terminated before the excitation current detected by the current detection circuit reaches the peak current value.

5. The control apparatus for a fuel injection valve according to claim 3 , wherein the electronic control unit is programmed not to calculate the variation ratio learned value when the energization period is smaller than a predetermined period.

6. The control apparatus for a fuel injection valve according to claim 4 , wherein the electronic control unit is programmed to set a quotient obtained by dividing a central characteristic value of the learned rise detection period by a minimum measurable value of the learned rise detection period as an initial value of the variation ratio learned value, and
the electronic control unit is programmed to set the injection standby period to be longer as a product obtained by multiplying the initial value of the variation ratio learned value by the learned rise detection period increases when calculation of the variation ratio learned value is not complete.

7. The control apparatus for a fuel injection valve according to claim 6 , wherein the electronic control unit is programmed to cause the value that is multiplied by the learned rise detection period when determining the injection standby period to approach the variation ratio learned value from the initial value of the variation ratio learned value gradually every time fuel is injected from the fuel injection valve, after the variation ratio learned value has been calculated.

8. The control apparatus for a fuel injection valve according to claim 3 , wherein the electronic control unit is programmed to calculate a product by multiplying the variation ratio learned value by the last learned rise detection period to be detected when an operating condition of an engine was previously in an injection permitted condition, and set the injection standby period to be longer as a value obtained by adding a temperature correction value to the product increases, when the operating condition of the engine shifts from an injection prohibited condition, in which fuel injection by the fuel injection valve is prohibited, to the injection permitted condition, in which fuel injection is performed by the fuel injection valve.

9. The control apparatus for a fuel injection valve according to claim 8 , wherein the temperature correction value takes a larger value as an amount by which a temperature of the fuel injection valve increases while the condition of the engine is in the injection prohibited condition.

10. The control apparatus for a fuel injection valve according to claim 3 , wherein the electronic control unit is programmed to calculate the variation ratio learned value when an engine temperature is included in a temperature range.

11. The control apparatus for a fuel injection valve according to claim 3 , wherein the electronic control unit is programmed to calculate the variation ratio learned value before a fixed period elapses following engine startup.

12. The control apparatus for a fuel injection valve according to claim 3 , the control apparatus including a battery, and the control apparatus further comprising a capacitor that is capable of applying a higher voltage than the battery,
wherein the drive control unit is programmed to supply power to the solenoid of the fuel injection valve from the capacitor from the energization start point to a point at which the excitation current reaches the peak current value, and
the electronic control uni

Assignees

• Nakano Tomohiro
• Murase Eiji
• Kaneko Rihito
• Toyota Motor Co Ltd

Inventors

• Nakano Tomohiro
• Murase Eiji
• Kaneko Rihito

Classifications

• F02D2041/2058

  using information of the actual current value · CPC title

• F02D41/20 Primary

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

• F02D41/40 Primary

  with means for controlling injection timing or duration · CPC title

• F02D2200/0602

  Fuel pressure · CPC title

• F02D2041/2055

  with means for determining actual opening or closing time · CPC title