Combustion engine variable compression ratio apparatus and method

• US 20040159292A1
• Filed: 02/18/2003
• Published: 08/19/2004
• Est. Priority Date: 02/18/2003
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Lawrence, Keith E., Dutart, Charles H., Strawbridge, Bryan E.
• Granted Patent: US 7,055,469 B2
• Time in Patent Office: Days
• US Class Current: 123/48AA
• CPC Class Codes: F01L 1/022 Chain drive
• CPC Class Codes: F01L 1/46 Component parts, details, or accessories, not provided for in preceding subgroups
• CPC Class Codes: F01L 13/00 Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
• 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 2275/14 Direct injection into combustion chamber
• CPC Class Codes: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02
• CPC Class Codes: F02B 75/042 the cylinderhead comprising a counter-piston
• CPC Class Codes: F02D 13/0269 Controlling the valves to perform a Miller-Atkinson cycle
• CPC Class Codes: F02D 15/04 by alteration of volume of compression space without changing piston stroke
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

An apparatus and method for varying a compression ratio of an engine having a block and a head mounted thereto. The apparatus and method includes a cylinder having a block portion and a head portion, a piston linearly movable in the block portion of the cylinder, a cylinder plug linearly movable in the head portion of the cylinder, and a valve located in the cylinder plug and operable to provide controlled fluid communication with the block portion of the cylinder.

Claims

1. An apparatus for varying a compression ratio of an engine having a block and a head mounted thereto, comprising:

a cylinder having a block portion and a head portion;

a piston linearly movable in the block portion of the cylinder;

a cylinder plug linearly movable in the head portion of the cylinder; and

a valve located in the cylinder plug and operable to provide controlled fluid communication with the block portion of the cylinder.

2. An apparatus, as set forth in claim 1, further including a fuel injector located in the cylinder plug and operable to inject fuel into the block portion of the cylinder.

3. An apparatus, as set forth in claim 1, wherein the valve located in the cylinder plug includes at least one of an intake valve and an exhaust valve.

4. An apparatus, as set forth in claim 1, further including a hydraulic system operable to controllably move the cylinder plug in the head portion of the cylinder.

5. An apparatus, as set forth in claim 1, further including a platform attached to the cylinder plug and operable to move with the cylinder plug.

6. An apparatus, as set forth in claim 5, wherein the platform includes a camshaft mounted thereto, the camshaft being configured to control operation of the valve.

7. An apparatus, as set forth in claim 6, wherein the camshaft is drivably connected to a crankshaft.

8. An apparatus, as set forth in claim 7, wherein the camshaft is configured to linearly move relative to the crankshaft and maintain a constant position relative to the platform.

9. An apparatus, as set forth in claim 8, further including a bevel gear drive connecting the camshaft to the crankshaft, the bevel gear drive including:

a first pair of bevel gears connecting the crankshaft to the bevel gear drive;

a second pair of bevel gears connecting the camshaft to the bevel gear drive; and

a sliding spline coupling connecting the first pair of bevel gears to the second pair of bevel gears and operable to vary in length in response to linear movement of the camshaft relative to the crankshaft.

10. An apparatus, as set forth in claim 4, wherein the cylinder plug, the head portion of the cylinder, and the head define a space operable to receive a supply of hydraulic fluid.

11. An apparatus, as set forth in claim 10, wherein the hydraulic system includes:

a source of hydraulic fluid;

a pump operable to pressurize the hydraulic fluid for delivery; and

a spool valve operable to controllably deliver the pressurized hydraulic fluid to the space defined by the cylinder plug, the head portion of the cylinder, and the head.

12. An apparatus, as set forth in claim 6, further including:

a fuel injector located in the cylinder plug and operable to inject fuel into the block portion of the cylinder;

a fuel rail located on the platform and connected to the fuel injector; and

a fuel pump located on the platform, drivably connected to the camshaft, and operable to deliver fuel to the fuel injector by way of the fuel rail.

13. An apparatus, as set forth in claim 3, further including:

an intake valve located in the cylinder plug;

an exhaust valve located in the cylinder plug;

an intake port located in the head;

an exhaust port located in the head;

an intake passageway located in the cylinder plug and operable to provide fluid communication from the intake port to the intake valve; and

an exhaust passageway located in the cylinder plug and operable to provide fluid communication from the exhaust port to the exhaust valve.

14. An apparatus, as set forth in claim 13, wherein at least one of the intake and exhaust passageways includes a chamfered surface to provide a fluid transition from a corresponding at least one of the intake and exhaust ports.

15. An apparatus, as set forth in claim 4, further including:

a position sensor operable to sense a linear position of the cylinder plug in the head portion of the cylinder and generate a responsive position signal; and

a controller operable to receive the position signal, determine a desired position of the cylinder plug, and responsively control the hydraulic system to move the cylinder plug to the desired position.

16. A cylinder plug for varying a compression ratio of an engine and linearly movable in a head portion of a cylinder, the cylinder further including a block portion and having a piston located therein, comprising:

an intake valve located in the cylinder plug and operable to provide controlled fluid communication with the block portion of the cylinder; and

an exhaust valve located in the cylinder plug and operable to provide controlled fluid communication with the block portion of the cylinder.

17. A cylinder plug, as set forth in claim 16, further including a fuel injector located in the cylinder plug and operable to inject fuel into the block portion of the cylinder.

18. A cylinder plug, as set forth in claim 17, further including:

an intake passageway located in the cylinder plug and operable to provide communication of intake fluid to the intake valve; and

an exhaust passageway located in the cylinder plug and operable to provide communication of exhaust fluid from the exhaust valve.

19. A cylinder plug, as set forth in claim 18, wherein the intake passageway includes a chamfered surface to provide fluid communication of the intake fluid.

20. A cylinder plug, as set forth in claim 18, further including at least one coolant passageway located in the cylinder plug.

21. An apparatus for varying a compression ratio of an engine, the engine having a block and a head mounted to the block, comprising:

a first cylinder portion located in the block;

a second cylinder portion located in the head and positioned such that the first and second cylinder portions create a cylinder;

a cylinder plug linearly movable within the second cylinder portion;

at least one valve located in the cylinder plug operable to provide controlled fluid communication with the first cylinder portion; and

a hydraulic system operable to move the cylinder plug to a desired position in the first cylinder portion.

22. An apparatus, as set forth in claim 21, wherein a cylinder plug includes a plurality of cylinder plugs, each cylinder plug being linearly movable within a corresponding one of a plurality of second cylinder portions, each second cylinder portion being associated with one of a corresponding plurality of first cylinder portions to create a plurality of cylinders.

23. An apparatus, as set forth in claim 22, wherein at least one valve includes:

at least one intake valve located in each cylinder plug operable to provide controlled fluid communication with each corresponding first cylinder portion; and

at least one exhaust valve located in each cylinder plug operable to provide controlled fluid communication with each corresponding first cylinder portion.

24. An apparatus, as set forth in claim 23, further including a fuel injector located in each cylinder plug and operable to inject fuel into each corresponding first cylinder portion.

25. An apparatus, as set forth in claim 22, wherein each cylinder plug, each corresponding second cylinder portion, and the head define a space operable to receive a supply of hydraulic fluid.

26. An apparatus, as set forth in claim 25, wherein the hydraulic system includes:

a source of hydraulic fluid;

a pump operable to pressurize the hydraulic fluid for delivery; and

a plurality of spool valves operable to controllably deliver the pressurized hydraulic fluid to the space defined by each corresponding cylinder plug, each corresponding second cylinder portion, and the head.

27. An apparatus, as set forth in claim 26, wherein the hydraulic system further includes a plurality of check valves located between the pump and each corresponding spool valve and operable to limit the direction of flow of hydraulic fluid to flow from the pump to each corresponding spool valve.

28. An apparatus, as set forth in claim 26, further including:

a plurality of position sensors, each operable to sense a linear position of each corresponding cylinder plug and generate a corresponding position signal; and

a controller operable to receive the position signals, determine a corresponding position of each cylinder plug, and responsively control actuation of each corresponding spool valve to move the cylinder plugs to the desired positions.

29. An apparatus, as set forth in claim 28, wherein the controller is further operable to control actuation of the spool valves to move the cylinder plugs during time intervals in which combustion in each corresponding cylinder is not occurring.

30. An apparatus, as set forth in claim 24, further including a platform attached to the cylinder plugs and operable to move with the cylinder plugs.

31. An apparatus, as set forth in claim 30, wherein the platform includes a camshaft mounted thereto, the camshaft being configured to control operation of the intake and exhaust valves.

32. An apparatus, as set forth in claim 31, further including:

a fuel rail located on the platform and connected to each fuel injector; and

a fuel pump located on the platform, drivably connected to the camshaft, and operable to deliver fuel to each fuel injector by way of the fuel rail.

33. An apparatus, as set forth in claim 30, wherein the cylinder plugs are located within an inner portion of the head and the platform is located at an outer portion of the head.

34. A method for varying a compression ratio of an engine, comprising the steps of:

determining a desired compression ratio;

determining a desired linear position of a cylinder plug located in a head portion of a cylinder as a function of the desired compression ratio;

actuating a hydraulic system to controllably move the cylinder plug to the desired position; and

controllably actuating at least one of an intake and an exhaust valve located in the cylinder plug, each valve being operable to provide fluid communication with a block portion of the cylinder from the desired position of the cylinder plug.

35. A method, as set forth in claim 34, further including the step of controllably actuating a fuel injector located in the cylinder plug, the fuel injector being operable to inject fuel into the block portion of the cylinder from the desired position of the cylinder plug.

36. A method, as set forth in claim 34, wherein actuating a hydraulic system includes the step of actuating a spool valve to control a supply of hydraulic fluid to the cylinder plug.

37. A method, as set forth in claim 34, wherein determining a desired linear position of the cylinder plug includes the step of determining a desired linear position of the cylinder plug with respect to the head portion of the cylinder.

38. A method, as set forth in claim 37, wherein determining a desired linear position of the cylinder plug includes the steps of sensing an actual position of the cylinder plug and determining a responsive desired position.