Method for controlling combustion system, combustion system, and internal combustion engine

Patent metadata

Field	Value
Publication number	US-12134995-B2
Application number	US-202118276926-A
Country	US
Kind code	B2
Filing date	Dec 13, 2021
Priority date	Jun 17, 2021
Publication date	Nov 5, 2024
Grant date	Nov 5, 2024

Abstract

A combustion system may include a piston, a fuel injector, and a cylinder. At a main fuel injection stage, the fuel injector injects a main fuel into the cylinder in sequence to drive the piston to work. A method for controlling the combustion system includes controlling the fuel injector to execute a first-stage main fuel injection in a compression stroke, the first-stage main fuel injection includes at least one injection, and continues till a power stroke such that the cylinder pressure in the cylinder reaches a target pressure peak value; and before the cylinder pressure in the cylinder reaches a descending critical point, executing a second-stage main fuel injection, the second-stage main fuel injection includes at least one injection, and the fuel injected in the second-stage main fuel injection and the fuel injected in the first-stage main fuel injection are superimposed.

First claim

The invention claimed is:

1. A method for controlling a combustion system, wherein the combustion system comprises a piston, a fuel injector and a cylinder, the fuel injector injects a main fuel into the cylinder in succession in a main fuel injection stage to drive the piston to work, and the method for controlling a combustion system comprises:
controlling the fuel injector to
execute a first-stage main fuel injection in a compression stroke to allow a cylinder pressure in the cylinder to reach a target pressure peak value, wherein the first-stage main fuel injection comprises at least one injection and lasts to a power stroke; and
execute a second-stage main fuel injection before the cylinder pressure in the cylinder is at a descending critical point to allow the cylinder pressure in the cylinder to be maintained at the target pressure peak value for a predetermined time, wherein the second-stage main fuel injection comprises at least one injection, and fuel injected in the second-stage main fuel injection and fuel injected in the first-stage main fuel injection are superimposed;
wherein a calibration parameter of a single main fuel injection is a parameter of the single main fuel injection calibrated when fuel consumption of an internal combustion engine is minimized and nitrogen oxide emission of the internal combustion engine is minimized under a condition of meeting an emission requirement of nitrogen oxides, the calibration parameter of the single main fuel injection comprises a calibration injection quantity of the single main fuel injection, and total injection quantity of the first-stage main fuel injection and the second-stage main fuel injection is equal to the calibration injection quantity of the single main fuel injection;
wherein an injection quantity of the first-stage main fuel injection is Q 1 , an injection quantity of the second-stage main fuel injection is Q 2 , and Q 2 is equal to 0.05Q 1 to 0.5Q 1 ;
wherein a duration of the first-stage main fuel injection is determined according to the injection quantity of the first-stage main fuel injection and an injection pressure of the first-stage main fuel injection, and a duration of the second-stage main fuel injection is determined according to the injection quantity of the second-stage main fuel injection and an injection pressure of the second-stage main fuel injection;
wherein the calibration parameter of the single main fuel injection further comprises a calibration injection pressure of the single main fuel injection, the injection pressure of the first-stage main fuel injection is greater than the calibration injection pressure of the single main fuel injection, and the injection pressure of the second-stage main fuel injection is greater than or equal to the injection pressure of the first-stage main fuel injection.

2. The method for controlling a combustion system according to claim 1 , wherein in a case that a difference presents between the cylinder pressure in the cylinder during the first-stage main fuel injection and the target pressure peak value, a fuel rail pressure is adjusted and/or an interval time between the second-stage main fuel injection and the first-stage main fuel injection is adjusted to allow the cylinder pressure in the cylinder to be equal to the target pressure peak value.

3. The method for controlling a combustion system according to claim 2 , wherein
in a case that the difference between the cylinder pressure in the cylinder during the first-stage main fuel injection and the target pressure peak value is less than or equal to 5%, the fuel rail pressure is adjusted to allow the cylinder pressure in the cylinder to reach the target pressure peak value;
in a case that the difference between the cylinder pressure in the cylinder during the first-stage main fuel injection and the target pressure peak value is greater than 5%, the fuel rail pressure is adjusted and the interval time between the second-stage main fuel injection and the first-stage main fuel injection is adjusted to allow the cylinder pressure in the cylinder to reach the target pressure peak value, or the interval time between the second-stage main fuel injection and the first-stage main fuel injection is adjusted to allow the cylinder pressure in the cylinder to reach the target pressure peak value.

4. The method for controlling a combustion system according to claim 2 , wherein the interval time between the second-stage main fuel injection and the first-stage main fuel injection is 300μs to 1200 μs.

5. The method for controlling a combustion system according to claim 1 , wherein a duration of the first-stage main fuel injection is determined according to the injection quantity of the first-stage main fuel injection and an injection pressure of the first-stage main fuel injection, and a duration of the second-stage main fuel injection is determined according to the injection quantity of the second-stage main fuel injection and an injection pressure of the second-stage main fuel injection.

6. The method for controlling a combustion system according to claim 5 , wherein the calibration parameter of the single main fuel injection further comprises a calibration injection pressure of the single main fuel injection, the injection pressure of the first-stage main fuel injection is greater than the calibration injection pressure of the single main fuel injection, and the injection pressure of the second-stage main fuel injection is greater than or equal to the injection pressure of the first-stage main fuel injection.

7. The method for controlling a combustion system according to claim 1 , wherein the duration of the first-stage main fuel injection and the duration of the second-stage main fuel injection are both within a range of 100 μs to 1500 μs.

8. The method for controlling a combustion system according to claim 7 , wherein the duration of the first-stage main fuel injection is within a range from a crank angle of 25° before a top dead center to the crank angle of 20° after a top dead center.

9. The method for controlling a combustion system according to claim 8 , wherein the predetermined time is 50% to 100% of the duration of the first-stage main fuel injection.

10. A combustion system, using the method for controlling the combustion system according to claim 1 , wherein a pressure sensor is arranged in the cylinder, and the pressure sensor is configured to detect the cylinder pressure in the cylinder.

11. An internal combustion engine, comprising the combustion system according to claim 10 .

Assignees

• Weichai Power Co Ltd

Inventors

• Tan Xuguang
• Tong Dehui
• Zhou Peng
• Liu Xiaoxin
• Pang Bin

Classifications

• F02D2041/389

  for injecting directly into the cylinder · CPC title

• F02D2200/024

  Fluid pressure of lubricating oil or working fluid · CPC title

• F02D41/3836

  Controlling the fuel pressure · CPC title

• F02D41/2467

  for injectors · CPC title

• F02D41/2432

  Methods of calibration · CPC title