Systems and methods for controlling enriched prechamber stoichiometry

Patent metadata

Field	Value
Publication number	US-10458312-B2
Application number	US-201715656944-A
Country	US
Kind code	B2
Filing date	Jul 21, 2017
Priority date	Jul 21, 2017
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

Abstract

A system for controlling enriched prechamber stoichiometry includes a prechamber ignition device, and an ignition control system that includes a sensor structured to measure an amount of at least one of CO2 or O2 in a prechamber, an engine timing sensor, a fuel quality sensor, and an electronic control unit. The electronic control unit is structured to receive signals from each of the sensors and determine an air-fuel ratio of the prechamber for comparison with a target air-fuel ratio, and produce a fuel delivery signal based on the comparison.

First claim

What is claimed is:

1. An ignition control system for an internal combustion engine comprising:
a sensor structured to measure at least one of CO2 or O2 in a combustion prechamber of a prechamber ignition device; and
an electronic control unit structured to:
receive data indicative of a residual amount of the at least one of CO2 or O2 produced by combustion of fuel and air in the combustion prechamber;
determine an air-fuel ratio in the combustion prechamber associated with production of the amount of the at least one of CO2 or O2; and
output a fuel delivery signal to adjust air-fuel ratio in the combustion prechamber towards a target air-fuel ratio.

2. The system of claim 1 further including a fuel quality sensor structured to measure a fuel parameter indicative of a ratio of hydrogen to carbon in a fuel supplied to the combustion prechamber.

3. The system of claim 1 wherein the electronic control unit is further structured to determine the air-fuel ratio based on the fuel parameter.

4. The system of claim 1 wherein the electronic control unit is further structured to determine a control command for a valve in a fuel supply system of the ignition control system based on the fuel delivery signal.

5. The system of claim 1 wherein the electronic control unit is further structured to compare the determined air-fuel ratio with a target air-fuel ratio, and generate the fuel delivery signal based on a difference between the determined air-fuel ratio and the target air-fuel ratio.

6. The system of claim 5 further including an engine timing sensor, wherein the determination of the air-fuel ratio is reflective of engine timing.

7. The system of claim 5 further comprising a prechamber ignition device having a combustion prechamber, and a spark ignition device coupled with the prechamber ignition device.

8. The system of claim 7 wherein the fuel supply system includes a supply of gaseous fuel.

9. The system of claim 1 wherein the electronic control unit is structured to determine the air-fuel ratio in the prechamber in an earlier engine cycle, and generate the fuel delivery signal to adjust the air-fuel ratio for a later engine cycle.

10. A method of adjusting stoichiometry of a combustion prechamber in an internal combustion engine comprising:
producing data indicative of an amount of at least one of CO2 or O2 produced by combustion of a first charge of air and fuel in a combustion prechamber;
outputting a fuel delivery signal to vary an amount of fuel delivered to the combustion prechamber after the combustion of the first charge of air and fuel; and
igniting a second charge of fuel and air in the combustion prechamber that has an amount of fuel that is based on the fuel delivery signal.

11. The method of claim 10 wherein the producing of the data includes producing the data by way of measuring the amount of at least one of CO2 or O2 of the first charge of air and fuel in the combustion prechamber using a sensor positioned at least partially within the combustion prechamber.

12. The method of claim 10 further comprising determining an air-fuel ratio from the data indicative of an amount of at least one of CO2 or O2 and data indicative of fuel quality.

13. The method of claim 12 further comprising comparing the determined air-fuel ratio with a target air-fuel ratio, and responsively generating the fuel delivery signal.

14. The method of claim 13 further comprising outputting an engine timing signal and wherein determination of the air-fuel ratio is responsive to the engine timing signal.

15. The method of claim 14 wherein the fuel includes a gaseous fuel, and further comprising spark-igniting each of the first charge of fuel and air and the second charge of fuel and air within the combustion prechamber.

16. An internal combustion engine comprising:
an engine block;
a cylinder formed in the engine block;
a piston disposed in the cylinder and movable between a top-dead-center (TDC) position and a bottom-dead-center (BDC) position, the piston and the cylinder defining a combustion chamber;
a prechamber ignition device having a combustion prechamber, and one or more ignition outlets fluidly connecting the combustion prechamber to the main combustion chamber at each of the BDC position and the TDC position; and
an ignition control system including a prechamber sensor structured to measure at least one of residual CO2 or O2 in the combustion prechamber produced by combustion of fuel and air in the combustion prechamber, an engine timing sensor, a fuel supply system structured to deliver a fuel to the combustion prechamber, and an electronic control unit; and
the electronic control unit being structured to control an air-fuel ratio in the combustion prechamber based on the measured at least one of residual CO2 or O2 and an engine timing indicated by the engine timing sensor.

17. The engine of claim 16 wherein the fuel supply system includes a fuel source, a fuel delivery line, and a valve disposed between the fuel source and the fuel delivery line.

18. The engine of claim 16 wherein the electronic control unit is structured to generate a fuel delivery signal to command the valve to deliver an amount of fuel to the combustion prechamber that adjusts the air-fuel ratio towards a target air-fuel ratio.

19. The engine of claim 16 wherein the fuel supply system includes a gaseous fuel supply system, and the engine further including an ignition device coupled to the combustion prechamber.

Assignees

• Caterpillar Inc

Inventors

• Wang Paul
• Ginter David
• Singh Jaswinder
• Kim Arnold

Classifications

• F02D41/1454

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

• F02B19/12

  with positive ignition (engines with non-timed positive ignition, and with incandescent chambers F02B9/08) · CPC title

• F02D2200/0611

  Fuel type, fuel composition or fuel quality · CPC title

• F02B19/1085 Primary

  controlling fuel injection · CPC title

• F02D41/1452

  the characteristics being a COx content or concentration · CPC title