Method and system for compensating for fuel injection deviations

Patent metadata

Field	Value
Publication number	US-11220973-B2
Application number	US-201916688606-A
Country	US
Kind code	B2
Filing date	Nov 19, 2019
Priority date	Jul 9, 2019
Publication date	Jan 11, 2022
Grant date	Jan 11, 2022

Abstract

A method of compensating for fuel injection deviations of injectors includes: in a case of a low flow rate operating range, learning cylinder-specific lambda deviations regarding cylinder-specific engine roughness deviations using a characteristic map defining a relationship between engine roughness deviations and lambda deviations; calculating cylinder-specific amounts of injection compensation necessary to remove the cylinder-specific lambda deviations; and compensating for amounts of injection of injectors a by adding the cylinder-specific amounts of injection compensation to cylinder-specific target amounts of injection.

First claim

What is claimed is:

1. A method of compensating for fuel injection deviations of injectors, the method comprising:
in a low flow rate injection operating range, learning, by a controller, cylinder-specific lambda deviations regarding cylinder-specific engine roughness deviations using a characteristic map defining a relationship between engine roughness deviations and lambda deviations;
calculating, by the controller, cylinder-specific amounts of injection compensation necessary to remove the cylinder-specific lambda deviations; and
compensating for amounts of injection of the injectors by adding the cylinder-specific amounts of injection compensation to cylinder-specific target amounts of injection,
wherein learning the cylinder-specific lambda deviations comprises:
detecting cylinder-specific values of engine roughness;
calculating an engine roughness average of the cylinder-specific values of engine roughness;
calculating the cylinder-specific engine roughness deviations from differences between the engine roughness average and the cylinder-specific values of engine roughness;
calculating the cylinder-specific lambda deviations regarding the cylinder-specific engine roughness deviations using the characteristic map; and
learning the cylinder-specific lambda deviations by integrating the cylinder-specific lambda deviations.

2. The method according to claim 1 , wherein whether or not a condition of the low flow rate injection operating range is satisfied is determined in accordance with a target injection time of one of the injectors, revolutions per minute of an engine, and a vehicle speed.

3. The method according to claim 2 , wherein whether or not a condition of compensation for the amounts of injection is satisfied is determined in accordance with whether or not a purging operation is active, a temperature of coolant for the engine, and the cylinder-specific engine roughness deviations.

4. The method according to claim 1 , wherein, when a target injection time of one of the injectors is within a predetermined time, revolutions per minute of an engine are less than predetermined revolutions per minute, and a vehicle speed is less than a predetermined vehicle speed, the low flow rate injection operating range is determined to be satisfied.

5. The method according to claim 4 , wherein, when a purging operation is inactivated, a temperature of coolant for the engine exceeds a predetermined temperature, and a maximum value of the cylinder-specific engine roughness deviations exceeds a predetermined value, an injection compensation operating condition is determined to be satisfied.

6. The method according to claim 1 , wherein learning the cylinder-specific lambda deviations further comprises:
calculating a lambda deviation average of the cylinder-specific lambda deviations;
when the lambda deviation average is not 0, compensating the lambda deviation average to be 0 by subtracting the lambda deviation average from the cylinder-specific lambda deviations; and when the lambda deviation average is 0, learning the cylinder-specific lambda deviations by integrating the cylinder-specific lambda deviations.

7. The method according to claim 6 , wherein the cylinder-specific lambda deviations are learned by reflecting table values of integration constants corresponding to the cylinder-specific lambda deviations.

8. The method according to claim 1 , wherein calculating the cylinder-specific amounts of injection compensation comprises:
calculating a cylinder-specific lambda from the cylinder-specific lambda deviations;
calculating cylinder-specific injection distribution values necessary for the cylinder-specific lambda to form a lambda average;
calculating cylinder-specific compensation injection values by subtracting an injection value corresponding to lambda 1 from the cylinder-specific injection distribution values; and
calculating the cylinder-specific amounts of injection compensation by multiplying the cylinder-specific compensation injection values with the cylinder-specific target amounts of injection.

9. The method according to claim 8 , wherein, in the calculating the cylinder-specific amounts of injection compensation, when a dual-injector structure in which two injectors are disposed in each of cylinders is used, injector-specific amounts of injection compensation of the cylinders are calculated by multiplying the cylinder-specific compensation injection values with injector-specific target amounts of injection of the cylinders.

10. The method according to claim 8 , wherein the cylinder-specific amounts of injection compensation are multiplied with a compensation factor according to a target injection time, where 0≤the compensation factor≤1.

11. The method according to claim 1 , wherein, after the compensation for the amounts of injection, when engine roughness deviation of a cylinder among the cylinders, in which the compensation for the amounts of injection is completed, is equal to or greater than a predetermined value, the cylinder-specific lambda deviation of the cylinder is reset to an initial value.

12. The method according to claim 1 , further comprising, after the compensating for amounts of injection:
calculating lambda deviation differences between initial cylinder-specific lambda deviations and current cylinder-specific lambda deviations;
when a maximum value among the lambda deviation differences exceeds a predetermined value, calculating an engine roughness deviation difference between an initial engine roughness deviation and a current engine roughness deviation of the corresponding cylinder; and
when the engine roughness deviation difference exceeds a preset value, resetting the lambda deviation of the corresponding cylinder to an initial value.

13. A system for compensating for fuel injection deviations of injectors, the system comprising a controller configured to:
determine whether or not an injection compensation operating condition is satisfied in a low flow rate injection operating range, in accordance with output values reflecting traveling states of a vehicle;
learn cylinder-specific lambda deviations regarding cylinder-specific engine roughness deviation using a characteristic map defining a relationship between engine roughness deviation and lambda deviations;
calculate cylinder-specific amounts of injection compensation necessary for removing the cylinder-specific lambda deviations; and
compensate for amounts of injection of the injectors by adding the cylinder-specific amounts of injection compensation to cylinder-specific target amounts of injection,
wherein the controller configured to learn the cylinder-specific lambda deviations by
detecting cylinder-specific values of engine roughness;
calculating an engine roughness average of the cylinder-specific values of engine roughness;
calculating the cylinder-specific engine roughness deviations from differences between the engine roughness average and the cylinder-specific values of engine roughness;
calculating the cylinder-specific lambda deviations regarding the cylinder-specific engine roughness deviations using the characteristic map; and
learning the cylinder-specific lambda deviations by integrating the cylinder-specific lambda deviations.

14. The system according to claim 13 , wherein the controller is further configured to determine whether or not an injection compensating operation is effective to reduce the engine roughness deviations by determining whether or not the engine roughness deviation of a cylinder, in which the compensation for the amounts of injection is completed, is equal to or greater than a predetermine

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Byeon Min

Classifications

• F02D41/1454

  the characteristics being an oxygen content or concentration or the air-fuel ratio · CPC title

• F02D41/0085

  Balancing of cylinder outputs, e.g. speed, torque or air-fuel ratio · CPC title

• F02D41/34

  with means for controlling injection timing or duration · CPC title

• F02D41/1458

  with determination means using an estimation · CPC title

• F02D41/2454

  Learning of the air-fuel ratio control · CPC title