Variable compression ratio device for internal combustion engine

• US 20030192490A1
• Filed: 04/15/2002
• Published: 10/16/2003
• Est. Priority Date: 04/15/2002
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Maloney, Ronald P., Faletti, James J.
• Granted Patent: US 6,708,655 B2
• Time in Patent Office: Days
• US Class Current: 123/48.00A
• CPC Class Codes: F02B 1/12 with compression ignition with fuel-air charge ignited by compression ignition of an additional fuel F02B7/00
• CPC Class Codes: F02B 75/042 the cylinderhead comprising a counter-piston

Abstract

An internal combustion engine, particularly suitable for use in a work machine, is provided with a combustion cylinder, a cylinder head at an end of the combustion cylinder and a primary piston reciprocally disposed within the combustion cylinder. The cylinder head includes a secondary cylinder and a secondary piston reciprocally disposed within the secondary cylinder. An actuator is coupled with the secondary piston for controlling the position of the secondary piston dependent upon the position of the primary piston. A communication port establishes fluid flow communication between the combustion cylinder and the secondary cylinder.

Claims

1. An internal combustion engine, comprising:

a combustion cylinder having an end;

a primary piston reciprocally disposed within said combustion cylinder;

a cylinder head including a bottom deck disposed at said end of said combustion cylinder, said cylinder head defining a secondary cylinder having a diameter;

a secondary piston reciprocally disposed within said secondary cylinder;

an actuator coupled with said secondary piston for controlling a position of said secondary piston dependent upon a position of said primary piston, thereby controlling commencement of a combustion event in said combustion cylinder; and

a communication port defined in said cylinder head establishing fluid flow communication between said combustion cylinder and said secondary cylinder, said communication port including an opening in said bottom deck and an opening to said secondary cylinder, said opening in said bottom deck being narrower than said diameter of said secondary cylinder.

2. The internal combustion engine of claim 1, said actuator including one of a cam actuator, solenoid actuator and a hydraulic actuator.

3. The internal combustion engine of claim 2, said communication port disposed near a periphery of said combustion cylinder.

4. The internal combustion engine of claim 2, said cylinder head including at least one intake port and at least one exhaust port.

5. The internal combustion engine of claim 2, said cylinder head including at least two intake ports and at least two exhaust ports.

6. The internal combustion engine of claim 5, said opening in said bottom deck disposed at a perimeter of said combustion cylinder

7. The internal combustion engine of claim 1, said communication port being unrestricted between said openings.

8. A work machine, comprising:

a frame; and

an internal combustion engine carried by said frame, said internal combustion engine including;

a combustion cylinder having an end;

a primary piston reciprocally disposed within said combustion cylinder;

a cylinder head including a bottom deck at said end of said combustion cylinder, said cylinder head including a secondary cylinder having a diameter;

a secondary piston reciprocally disposed within said secondary cylinder;

an actuator coupled with said secondary piston for controlling a position of said secondary piston dependent upon a position of said primary piston, and thereby controlling commencement of a combustion event in said combustion cylinder; and

a communication port defined in said cylinder head establishing fluid flow communication between said combustion cylinder and said secondary cylinder, said communication port having a diameter less than said diameter of said secondary cylinder.

9. The work machine of claim 8, said actuator including one of a cam actuator and a hydraulic actuator.

10. The work machine of claim 9, said communication port disposed near a periphery of said combustion cylinder.

11. The work machine of claim 8, said communication port disposed near a periphery of said combustion cylinder.

12. The work machine of claim 8, said cylinder head including an intake port and an exhaust port, and said communication port disposed in said cylinder head radially outwardly of said intake and exhaust ports.

13. The work machine of claim 8, said cylinder head including two intake ports and two exhaust ports, and said communication port disposed in said cylinder head radially outwardly of said intake and exhaust ports.

14. The work machine of claim 8, said communication port having an opening in said combustion cylinder and an opening in said secondary cylinder, each said opening being narrower than said secondary cylinder.

15. A method of operating an internal combustion engine, comprising the steps of:

reciprocating a primary piston within a combustion cylinder having an end;

reciprocating a secondary piston within a secondary cylinder adjacent said end, said reciprocating step being carried out such that said secondary piston has a position within said secondary cylinder which is dependent upon a position of said primary piston within said combustion cylinder;

providing a combustable fuel to said combustion cylinder;

communicating fluid flow between said secondary cylinder and said combustion cylinder, said communicating fluid flow step being carried out through a communication port having an opening in said combustion cylinder and an opening in said secondary cylinder, each said opening being narrower than said cylinders; and

controlling commencement of a combustion event in said combustion cylinder through control of the position of said secondary piston.

16. The method of claim 15, said step of reciprocating said primary piston including moving said primary piston to a top dead center position within said combustion cylinder, and combusting a fuel and air mixture within said combustion cylinder when said primary piston is at or near said top dead center position.

17. The method of claim 16, said step of reciprocating said secondary piston including moving said secondary piston to a top dead center position within said secondary cylinder when said primary piston is at or near said corresponding top dead center position.

18. The method of claim 17, said step of reciprocating said secondary piston being carried out with a hydraulic actuator coupled with said secondary piston, said hydraulic actuator providing said primary piston and said combustion cylinder with a variable compression ratio.

19. The method of claim 15, said step of reciprocating said secondary piston being carried out with a hydraulic actuator coupled with said secondary piston, said hydraulic actuator providing said primary piston and said combustion cylinder with a variable compression ratio.

20. The method of claim 19, including the substep of holding said secondary piston at said top dead center position when said primary piston is at or near a corresponding top dead center position.