Adiabatic, two-stroke cycle engine having piston-phasing and compression ratio control system

• US 5,507,253 A
• Filed: 09/23/1994
• Issued: 04/16/1996
• Est. Priority Date: 08/27/1993
• Status: Expired due to Term

• Current Assignee: Alvin Lowi Jr
• Original Assignee: Alvin Lowi Jr
• Inventors: Lowi, Alvin Jr.
• Primary Examiner(s): MCMAHON, MARGUERITE J
• Application Number:
  US08/311,348
• Time in Patent Office: 571 Days
• Field of Search: 123/55.7, 123/56.1, 123/56.2, 123/56.8, 123/56.9, 123/51 B, 123/193.6
• US Class Current: 123/56.9
• CPC Class Codes: F01B 3/045 by two or more curved surfaces, e.g. for two or more pistons in one cylinder
• CPC Class Codes: F01B 7/02 with oppositely reciprocating pistons
• CPC Class Codes: F01B 7/14 acting on different main shafts
• CPC Class Codes: F02B 2075/025 two
• CPC Class Codes: F02B 2075/1816 four
• 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 75/002 Double acting engines
• CPC Class Codes: F02B 75/26 Engines with cylinder axes coaxial with, or parallel or inclined to, main-shaft axis; Engines with cylinder axes arranged substantially tangentially to a circle centred on main-shaft axis
• CPC Class Codes: F02B 75/28 Engines with two or more pistons reciprocating within same cylinder or within essentially coaxial cylinders arranged oppositely relative to main shaft F02B75/24
• CPC Class Codes: F02B 75/282 the pistons having equal strokes

Abstract

An engine structure and mechanism that operates on various combustion processes in a two-stroke-cycle without supplemental cooling or lubrication comprises an axial assembly of cylindrical modules and twin, double-harmonic cams that operate with opposed pistons in each cylinder through fully captured rolling contact bearings. The opposed pistons are double-acting, performing a two-stroke engine power cycle on facing ends and induction and scavenge air compression on their outside ends, all within the same cylinder bore. The engine includes a control system which utilizes twin barrel cams with adjustable axial and angular positions enabling independent compression ratio and port phasing variation during operation. The engine control system comprises one or more electrohydraulic servos to set and maintain the axial and angular relationships of the cams either at extreme positions or controlled to particular positions and schedules thereof utilizing instantaneous piston position feedback information.

Claims

1. A reciprocating internal combustion engine comprising:

at least two cylinders, each of said cylinders having a first end and a second end;

a pair of opposed pistons in each of said cylinders, each of said pistons comprising a piston head and a piston rod;

a pair of double harmonic barrel cams mounted on a shaft parallel and symmetrical with said cylinders, said cams connected to said piston rods to impart axial motion thereto;

each of said cams having a centrally disposed cam wheel affixed to said shaft;

an axially movable cam rim mounted to the peripheral surface of each of said cam wheels;

a cam ring affixed to the peripheral surface of each of said cam rims;

an annular space between each of said cam wheels and each of said movable cam rims;

means for controlling the volume of each of said annular spaces to change the axial position of said respective rim with respect to said respective wheel; and

one or more means for rotating each of said rims with respect to said respective wheel, independently of the change of axial position.

2. The engine of claim 1 wherein said annular space volume controlling means comprises an electro-hydraulic position servo.

3. The engine of claim 1 wherein each of said means for rotating said rim comprises:

an axial slot in said respective cam rim; and

a movable key fitted into said axial slot;

said key affixed to cranking means for imparting tangential motion to said key with respect to said wheel thereby imparting tangential motion to said rim;

said cranking means affixed to said respective cam wheel.

4. The engine of claim 3 further comprising:

a cylindrical space within said cam wheel;

a piston movable within said space; and

means for controlling the volume of said cylindrical space to move said piston with respect to said cam wheel to operate said cranking means.

5. The engine of claim 4 wherein said cranking means comprises a bell crank.

6. The engine of claim 4 wherein said cylindrical space volume controlling means comprises an electro-hydraulic position servo.

7. The engine of claim 4 wherein said annular space volume controlling means and said cylindrical space volume controlling means comprise electro-hydraulic position servos.

8. The engine of claim 7 wherein said annular space volume controlling means for said cam pair comprises a single electro-hydraulic position servo valve.

9. The engine of claim 7 further comprising a first electro-hydraulic position servo valve for changing the axial position of a first cam rim and a second electro-hydraulic position servo valve for changing the axial position of a second cam rim.

10. The engine of claim 7 wherein said cylindrical space volume controlling means for said cam pair comprises a single hydraulic position servo valve.

11. The engine of claim 7 further comprising a first hydraulic position servo valve for rotating a first cam rim and a second hydraulic position servo valve for rotating a second cam rim.

12. The engine of claim 1 further comprising means for monitoring the position of a piston pair and means for controlling both the phasing and clearance of all of said pistons.

13. The engine of claim 12 wherein said monitoring means comprises a pair of linear variable differential transformers, each of said transformers affixed to said rod of one of said piston pair.

14. The engine of claim 12 wherein said controlling means comprises a microprocessor and a feedback system comprising said monitoring means, said annular space volume controlling means and said cylindrical space volume controlling means.

15. A reciprocating internal combustion engine comprising:

at least two cylinders, each of said cylinders having a first end and a second end;

a pair of opposed pistons in each of said cylinders, each of said pistons comprising a piston head and a piston rod;

a pair of double harmonic barrel cams mounted on a shaft parallel to and symmetrical with said cylinders, said cams connected to said piston rods to impart axial motion thereto;

a centrally disposed cam wheel affixed to said shaft;

an axially movable cam rim mounted to the peripheral surface of said cam wheel;

a cam ring affixed to the peripheral surface of said cam rim;

an annular space between said cam wheel and said movable cam rim;

means for controlling the volume of said annular space to change the axial position of said rim with respect to said wheel; and

one or more means for rotating said rim with respect to said wheel in conjunction with said change on axial position of said rim.

16. The engine of claim 15 wherein each of said means for rotating said rim comprises:

an axial slot in said cam rim;

a helical slot in said cam wheel in communication with said axial slot; and

a beveled key bolted into said axial slot and cantilevered into said helical slot.