Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Reexamination Certificate
2003-09-22
2004-11-16
Denion, Thomas (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
C123S090290
Reexamination Certificate
active
06817326
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS, IF ANY
Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
REFERENCE TO A MICROFICHE APPENDIX, IF ANY
Not applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is a valve system for controlling the charging and exhausting of the combustion chamber(s) of internal combustion engines.
2. Background Information
This invention applies to charging and exhausting the combustion chamber(s) of internal combustion engines in an efficient manner.
Four stroke-cycle engines of common design breathe through two or more concentric poppet valves featuring angled seating areas. While modern engines have become much more efficient than previous examples by the incorporation of smaller included valve angles, increased valve area, and better port design, poppet valves by nature mask the ports which they control. In essence, the gas flow into and out of the combustion chamber must go around the head of the open valve(s) to proceed through the port(s). This limits the volumetric efficiency of the engine. These valves are opened by radial lobes of a rotating camshaft. The base diameter of the camshaft lobes is largely dictated by the design valve lift, as the camshaft must ramp the valves open and closed smoothly, and at the proper time. To fit the timing constraints, the valves are ramped to full open, then ramped closed with essentially no duration at the fill open position. To maintain smooth and properly timed valve actuation, significant increases in cam lobe base diameter are not possible with poppet valves. With the exception of desmodromic designs, high-rate springs are used to make the valves follow the profile of the camshaft lobes. These strong springs are required to control valve float at elevated engine speeds. Valve float causes the engine to run erratically, or even causes the valve(s) to destructively collide with the cylinder's piston. Each time the valves are opened, energy is expended to overcome the tension of the valve springs. The high spring tension also forces more robust design in related valve-train components. Known attempts to overcome these problems generally have had lubrication, oil control, and/or sealing issues.
Applicant has invented a valve system which lessens valve-port masking, opens the ports rapidly, has relatively long filly open duration, and also closes the ports rapidly. This system does not require that long-travel, high-rate springs be compressed. The asymmetrical valves of this system are palindromically controlled, and destructive valve float is eliminated. There is no unlubricated sliding or rotating motion, and oil control is the same as in conventional designs. A relatively larger diameter camshaft allows more precise valve actuation. The absence of long-travel, high-rate springs provides for the option of using electromechanical actuators in place of the camshaft.
SUMMARY OF THE INVENTION
The invention is a valve system to control the charging and exhausting of combustion chamber fluids of internal combustion engines. The valve system includes a cylinder head adapted for securing to a multi-level combustion chamber, the cylinder head including asymmetrical ports which open into the combustion chamber on separate levels. Each port is controlled by a valve member larger than the port, the valve member of similar shape as the port, each valve member providing a flat sealing area for contacting the port periphery. Each valve member has a non-centered cylindrical stem operatively traveling in a cylindrical valve guide sealed by a valve guide seal, each valve stem protruding through an end of the valve guide opposite the combustion chamber to locate a valve spring and accept a follower which captures the valve spring. Each follower is operatively associated with a valve operating assembly to selectively provide axial movement and rotational movement to each valve member and valve stem. The valve operating assembly first moves the valve member a nominal distance from the port periphery to unseal the port, then rotates the valve member in one direction to open the associated port, next rotates the valve member in an opposite direction to close the associated port, and finally moves the valve member a nominal distance to contact the port periphery and seal the port.
One embodiment of the valve system includes a specially designed cylinder head with two or more asymmetrical valve members with valve bodies shaped as needed to provide sufficient port area for the particular application. These valve members have conventional cylindrical stems which are offset from the center of the valve's body. The valve member's cover ports are shaped to match the valve's shape, with the ports somewhat smaller to provide a flat sealing surface completely around their periphery. Optionally, a matching seal, larger than the port, but smaller than the valve body, may be fitted to the sealing area. The valve stems travel in conventional valve guides which are machined or pressed into the cylinder head, and which are sealed by conventional valve guide seals. The one embodiment of the valve system function as follows. A radial protrusion on an overhead camshaft, rotating at one-half crankshaft rpm, overcomes a valve spring and lifts the valve member a nominal distance off its sealing surface. Next, a circumferential groove on the camshaft acting on a follower, rotates the valve body to open the port, then rotates the valve member back to its original position to close the port. Once the valve member is back in its original position, the radial protrusion lowers the valve member back to its seated position. The camshaft diameter is not dictated by design valve lift and can be relatively larger to achieve desired valve member motion. A multi-level combustion. chamber allows relatively larger valve and port area. The valve members can be larger than conventional designs, because they operate on different planes and don't interfere with each others path. In this design, the ports are oriented such that the valve guides are in line parallel with the crankshaft, allowing the use of a single camshaft driven by a simple chain or gear belt. Other designs with more valve members and multiple camshafts are possible, including separate camshafts for lift and for rotation.
In another embodiment of the invention, the camshaft(s) is replaced with electromechanical actuators. This is possible as the present invention features minimal valve spring force to overcome, as compared with conventional designs. In this embodiment, separate actuators for lift and for rotation open and close each valve member. The actuators can be solenoids, or solenoid controlled pneumatic cylinders. In the case of pneumatic actuation, air pressure is supplied by a pump powered by the engine and by a reservoir. Also, in this embodiment, continuously variable valve timing is provided by a control module acting on inputs such as crankshaft rpm, throttle position, inlet tract vacuum and other operating parameters. The present invention is described for a single cylinder engine design. The valve system is also applicable to multi-cylinder engines.
REFERENCES:
patent: 556195 (1896-03-01), Mellars
patent: 1007491 (1911-10-01), Reynolds
patent: 1131707 (1915-03-01), Johnson
patent: 1172871 (1916-02-01), Cobb
patent: 1211604 (1917-01-01), Lewis
patent: 1241662 (1917-10-01), Ronconi
patent: 1274300 (1918-07-01), McInturff
patent: 1363363 (1920-12-01), Sinclair
patent: 1698040 (1929-01-01), White
patent: 1707086 (1929-03-01), Kuske
patent: 1877760 (1932-09-01), Berner et al.
patent: 1903802 (1933-04-01), Agerell
patent: 1907214 (1933-05-01), Nyquist
patent: 1923666 (1933-08-01), French
patent: 2409350 (1946-10-01), Forrest
patent: 2741931 (1956-04-01), Sills
patent: 4113268 (1978-09-01), Simmons et al.
patent: 4309966 (1982-01-01), Klomp
patent: 4739968 (1988-04-01), Schabinger
patent: 4765287 (1988-08-01), Taylor et al.
patent: 5040498 (1991-08-01), Scherer
patent: 5503130 (1996-04-01),
Denion Thomas
Eshete Zelalem
Randall Tipton L.
LandOfFree
Valve system for internal combustion engines does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Valve system for internal combustion engines, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Valve system for internal combustion engines will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3317763