Method of operating a fuel injector

Patent metadata

Field	Value
Publication number	US-10450987-B2
Application number	US-201615298888-A
Country	US
Kind code	B2
Filing date	Oct 20, 2016
Priority date	Oct 20, 2015
Publication date	Oct 22, 2019
Grant date	Oct 22, 2019

Abstract

A method of operating a fuel injector of an internal combustion engine includes setting a value of a target fuel quantity to be injected by the fuel injector, initializing a value of a fuel quantity requested from the fuel injector to the value of the target fuel quantity, and correcting the value of the requested fuel quantity. A first learning cycle is performed to correct the value of the requested fuel quantity in which a difference between the target fuel quantity and the injected fuel quantity is calculated and added to the requested fuel quantity to provide a corrected value. The corrected value of the requested fuel quantity is used to determine a reference value of an energizing time that causes the fuel injector to inject a fuel quantity corresponding to the target fuel quantity. The fuel injector is operated based on the determined reference value of the energizing time.

First claim

What is claimed is:

1. A method of operating a fuel injector of an internal combustion engine comprising:
setting a value of a target fuel quantity to be injected by the fuel injector;
initializing a value of a fuel quantity requested from the fuel injector to the value of the target fuel quantity;
correcting the value of the requested fuel quantity, wherein the correction of the value of the requested fuel quantity includes performing a first learning cycle including:
determining a value of an energizing time corresponding to the value of the requested fuel quantity;
performing a fuel injection by energizing the fuel injector for the determined value of energizing time;
measuring a value of an oxygen concentration in an exhaust gas;
determining a value a fuel quantity that has been injected by the fuel injector as a function of the measured value of the oxygen concentration;
calculating a difference between the value of the target fuel quantity and the value of the injected fuel quantity;
adding the value of the requested fuel quantity to the calculated difference to yield a corrected value of the requested fuel quantity;

determining a reference value of an energizing time using the corrected value of the requested fuel quantity for causing the fuel injector to inject the target fuel quantity; and
operating the fuel injector based on the determined reference value of the energizing time, wherein the value of the injected fuel quantity is calculated according to the following formula:

Qa
=

k
⁢

m
.

λ
⁢

⁢
m

wherein:
Qa is the value of the fuel quantity injected during the fuel injection,
{dot over (m)} is an amount of air disposed into a combustion chamber during the fuel injection,
λm is the measured quantity of oxygen concentration, and
k is proportionality constant, wherein the proportionality constant is calculated according the following formula:

k
=

Nc
⁢

/

⁢
Np

α
⁢

⁢
s
*
ρ

wherein:
k is the proportionality constant,
Nc is a number of combustion chambers of the internal combustion engine,
Np is a number of energizing pulses of the fuel injector to perform a fuel injection,
αs is the value of a stoichiometric air to fuel ratio, and
ρ is a value of a density of the fuel.

2. The method according to claim 1 , wherein the correction of the value of the requested fuel quantity further comprises repeatedly performing the first learning cycle for a predetermined number of times.

3. The method according to claim 2 , wherein the predetermined number of times is in the range of three to five times.

4. The method according to claim 1 , wherein the determination of the reference value of the energizing time comprises:
determining a value of an energizing time corresponding to the corrected value of the requested fuel quantity; and
performing a second learning cycle including:
performing a fuel injection by energizing the fuel injector for the determined value of energizing time;
measuring a value of an oxygen concentration in an exhaust gas;
increasing the determined value of the energizing time by a predetermined amount and repeat the second learning cycle, if the measured value of the oxygen concentration is larger than an expected value thereof;
decreasing the determined value of the energizing time by the predetermined amount and repeat the second learning cycle, if the measured value of the oxygen concentration is smaller than the expected value, and
identifying the determined value of the energizing time as the reference value thereof, if the measured value of the oxygen concentration is equal to the expected value thereof.

5. A non-transitory computer readable medium comprising a computer program having programming instructions which when executed on a computer, is configured to:
set a value of a target fuel quantity to be injected by the fuel injector;
initialize a value of a fuel quantity requested from the fuel injector to the value of the target fuel quantity;
correct the value of the requested fuel quantity;
determine a reference value of an energizing time using the corrected value of the requested fuel quantity for causing the fuel injector to inject the target fuel quantity;
operate the fuel injector based on the determined reference value of the energizing time;
wherein the correction of the value of the requested fuel quantity includes performing a first learning cycle including:
determining a value of an energizing time corresponding to the value of the requested fuel quantity;
performing a fuel injection by energizing the fuel injector for the determined value of energizing time;
measuring a value of an oxygen concentration in an exhaust gas;
determining a value a fuel quantity that has been injected by the fuel injector as a function of the measured value of the oxygen concentration;
calculating a difference between the value of the target fuel quantity and the value of the injected fuel quantity; and
adding the value of the requested fuel quantity to the calculated difference to yield a corrected value of the requested fuel quantity;

wherein the computer program further comprises programming instructions which when executed on a computer, is configured to:
calculate the value of the injected fuel quantity according to the following formula:

Qa
=

k
⁢

m
.

λ
⁢

⁢
m

wherein:
Qa is the value of the fuel quantity injected during the fuel injection,
{dot over (m)} is an amount of air disposed into a combustion chamber during the fuel injection,
λm is the measured quantity of oxygen concentration, and
k is a proportionality constant calculated according the following formula:

k
=

Nc
⁢

/

⁢
Np

α
⁢

⁢
s
*
ρ

Assignees

• Gm Global Tech Operations Llc

Inventors

• Tordin Serena
• Nuzzo Valerio
• Claude Paul Leonardo
• Cancellieri Angelo

Classifications

• F02D2041/389

  for injecting directly into the cylinder · CPC title

• F02D41/2432

  Methods of calibration · CPC title

• F02D41/38

  of the high pressure type · CPC title

• F02D41/182

  for the control of a fuel injection device · CPC title

• F02D41/2464 Primary

  Characteristics of actuators · CPC title