Control system for an engine cylinder with fuel control of pre chamber and main chamber

Patent metadata

Field	Value
Publication number	US-9903264-B1
Application number	US-201615296181-A
Country	US
Kind code	B1
Filing date	Oct 18, 2016
Priority date	Oct 18, 2016
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

A control system for an engine cylinder having a pre-chamber and a main chamber includes a pressure sensor being provided in the pre-chamber, and a processor coupled to the pressure sensor. The processor is configured to measure pre-chamber pressure using the pressure sensor, determine a peak pre-chamber pressure from the measured pre-chamber pressure, calculate an estimated main chamber pressure corresponding to the peak pre-chamber pressure from at least one cylinder condition at ignition, calculate a pressure ratio of the peak pre-chamber pressure to the estimated main chamber pressure, calculate a fuel parameter for at least one of the pre-chamber and main chamber from the pressure ratio to achieve a desired pressure ratio, and generate a control signal to provide fuel to at least one of the pre-chamber and main chamber in accordance with the fuel parameter.

First claim

What is claimed is:

1. A control system for an engine cylinder comprising a pre-chamber and a main chamber, the control system comprising:
a pressure sensor being provided in the pre-chamber;
a processor configured to perform the method steps of:
measuring pre-chamber pressure using the pressure sensor;
determining a peak pre-chamber pressure from the measured pre-chamber pressure;
calculating an estimated main chamber pressure corresponding to the peak pre-chamber pressure from at least one cylinder condition at ignition;
calculating a pressure ratio of the peak pre-chamber pressure to the estimated main chamber pressure;
calculating a fuel parameter for at least one of the pre-chamber and main chamber from the pressure ratio to achieve a desired pressure ratio; and
generating a control signal to provide fuel to at least one of the pre-chamber and main chamber in accordance with the fuel parameter.

2. The control system of claim 1 , wherein the processor is further configured to determine the peak pre-chamber pressure as the measured pre-chamber pressure at a zero-crossing of a first derivative of the measured pre-chamber pressure.

3. The control system of claim 2 , wherein the processor is further configured to determine the peak pre-chamber pressure within a first predetermined crank angle range.

4. The control system of claim 1 , wherein the at least one cylinder condition comprises cylinder pressure at ignition and cylinder volume at ignition.

5. The control system of claim 4 , wherein the processor is further configured to calculate the estimated main chamber pressure according to:

P

main
⁢

⁢
chamber

=

P
ignition

⁢

V
ignition
κ

V

main
⁢

⁢
chamber

κ

,

where P main chamber is the estimated main chamber pressure at a crank angle corresponding to the peak pre-chamber pressure, P ignition is the cylinder pressure at ignition, V ignition is the cylinder volume at ignition, V main chamber is the cylinder volume at the crank angle corresponding to the peak pre-chamber pressure, and κ is a polytropic coefficient.

6. The control system of claim 1 , wherein the processor is further configured to determine an estimated peak main chamber pressure from the measured pre-chamber pressure within a second predetermined crank angle range.

7. A method for controlling an engine cylinder comprising a pre-chamber and a main chamber, a pressure sensor being provided in the pre-chamber, the method comprising:
measuring pre-chamber pressure using the pressure sensor;
determining, using a processor, a peak pre-chamber pressure from the measured pre-chamber pressure;
calculating, using the processor, an estimated main chamber pressure corresponding to the peak pre-chamber pressure from at least one cylinder condition at ignition;
calculating, using the processor, a pressure ratio of the peak pre-chamber pressure to the estimated main chamber pressure;
calculating, using the processor, a fuel parameter for at least one of the pre-chamber and main chamber from the pressure ratio to achieve a desired pressure ratio; and
providing fuel to at least one of the pre-chamber and main chamber in accordance with the fuel parameter.

8. The method of claim 7 , wherein determining a peak pre-chamber pressure comprises determining the measured pre-chamber pressure at a zero-crossing of a first derivative of the measured pre-chamber pressure.

9. The method of claim 8 , wherein the peak pre-chamber pressure is determined within a first predetermined crank angle range.

10. The method of claim 7 , wherein the at least one cylinder condition comprises cylinder pressure at ignition and cylinder volume at ignition.

11. The method of claim 10 , wherein the estimated main chamber pressure is calculated according to:

P

main
⁢

⁢
chamber

=

P
ignition

⁢

V
ignition
κ

V

main
⁢

⁢
chamber

κ

,

where P main chamber is the estimated main chamber pressure, P ignition is the cylinder pressure at ignition, V ignition is the cylinder volume at ignition, V main chamber is the cylinder volume at a crank angle corresponding to the peak pre-chamber pressure, and κ is a polytropic coefficient.

12. The method of claim 7 , further comprising determining an estimated peak main chamber pressure from the measured pre-chamber pressure within a second predetermined crank angle range.

13. A non-transient computer-readable medium containing program instructions for causing a processor to perform the method of claim 7 .

Assignees

• Caterpillar Inc

Inventors

• Yeager Mary Louise
• BURGER Lucas Allen
• Loetz Andrew
• Zook Brett

Classifications

• F02B43/10

  Engines or plants characterised by use of other specific gases, e.g. acetylene, oxyhydrogen · CPC title

• F02B19/1085 Primary

  controlling fuel injection · CPC title

• F02D41/3094

  the fuel injection being effected by at least two different injectors, e.g. one in the intake manifold and one in the cylinder · CPC title

• F02D41/1439

  characterised by the position of the sensor · CPC title

• F02B19/12

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