Positive control (desmodromic) valve systems for internal combustion engines

Abstract

Various types of valve systems are disclosed herein. In one embodiment, a positive control reciprocating sleeve valve system for use with an internal combustion engine includes opening and closing rockers controlled by corresponding opening and closing cam lobes. In one aspect of this embodiment, interference can be designed into the valve control system to provide additional “hold-closed” force to hold the valve against its seat during a portion of the engine cycle. In another aspect of this embodiment, positive control valve systems can include compliant components and systems, hydraulic systems, pneumatic systems, and/or mechanical spring systems to control valve lash, facilitate sealing, etc.

What is claimed: 
     
         1 . An internal combustion engine comprising:
 a combustion chamber;   a reciprocating sleeve valve configured to cooperate with a valve seat;   a first rocker arm that drives the sleeve valve away from the valve seat;   a second rocker arm that drives the sleeve valve toward the valve seat; and   a desmodromic valve actuation system comprising the first and second rocker arms, which are operably coupled to the sleeve valve, wherein the desmodromic valve actuation system alternates between driving the sleeve valve away from the valve seat by movement of the first rocker arm and driving the sleeve valve toward the valve seat by movement of the second rocker arm.   
     
     
         2 . The internal combustion engine of  claim 1 , further comprising a passage in fluid communication with the combustion chamber, wherein the desmodromic valve actuation system alternates between driving the sleeve valve away from the valve seat to open the passage and driving the sleeve valve toward the valve seat to close the passage during operation of the engine. 
     
     
         3 . The internal combustion engine of  claim 2 , wherein the passage is an inlet passage configured to introduce a combustible charge into the combustion chamber. 
     
     
         4 . The internal combustion engine of  claim 2 , wherein the passage is an exhaust passage configured to accept exhaust combustion products from the combustion chamber. 
     
     
         5 . The internal combustion engine of  claim 1 , wherein the sleeve valve includes an external flange, and wherein the first rocker arm operably engages the flange and drives the sleeve valve away from the valve seat and the second rocker arm operably engages the flange and drives the sleeve valve toward the valve seat. 
     
     
         6 . The internal combustion engine of  claim 1 , wherein the desmodromic valve actuation system includes first and second cam lobes, wherein rotation of the first cam lobe results in movement of the first rocker arm and drives the sleeve valve away from the valve seat, and wherein rotation of the second cam lobe results in movement of the second rocker arm and drives the sleeve valve toward the valve seat. 
     
     
         7 . The internal combustion engine of  claim 1 , wherein the desmodromic valve actuation system includes a camshaft having first and second cam lobes, wherein rotation of the first cam lobe results in movement of the first rocker arm and drives the sleeve valve away from the valve seat, and wherein rotation of the second cam lobe results in movement of the second rocker arm and drives the sleeve valve toward the valve seat. 
     
     
         8 . The internal combustion engine of  claim 1 , wherein the desmodromic valve actuation system includes:
 a first cam lobe;   a second cam lobe;   wherein the first rocker arm is disposed between the first cam lobe and the sleeve valve, and wherein rotation of the first cam lobe causes the first rocker arm to drive the sleeve valve away from the valve seat and open a passage in fluid communication with the combustion chamber; and   wherein the second rocker arm is disposed between the second cam lobe and the sleeve valve, and wherein rotation of the second cam lobe causes the second rocker arm to drive the sleeve valve toward the valve seat and close the passage.   
     
     
         9 . The internal combustion engine of  claim 1 , wherein the desmodromic valve actuation system includes:
 a first cam lobe;   a second cam lobe;   wherein the first rocker arm comprises a first end portion spaced apart from a second end portion,   wherein the first end portion is coupled to the first cam lobe, wherein the second end portion has a first arm disposed on a first side of the sleeve valve and a second arm disposed on a second side of the sleeve valve, opposite the first side, and wherein rotation of the first cam lobe causes the first rocker arm to drive the sleeve valve away from the valve seat to open a passage in fluid communication with the combustion chamber; and   wherein the second rocker arm comprises a third end portion spaced apart from a fourth end portion, wherein the third end portion is coupled to the second cam lobe, wherein the fourth end portion has a third arm disposed on the first side of the sleeve valve and a second arm disposed on the second side of the sleeve valve, and wherein rotation of the second cam lobe causes the second rocker arm to drive the sleeve valve toward the valve seat to close the passage.   
     
     
         10 . The internal combustion engine of  claim 1 , wherein the sleeve valve includes a cylindrical bore, and wherein the engine further comprises a reciprocating piston operably disposed within the cylindrical bore. 
     
     
         11 . The internal combustion engine of  claim 1 , wherein the sleeve valve is a first sleeve valve having a first cylindrical bore, and wherein the engine further comprises:
 a second reciprocating sleeve valve having a second cylindrical bore coaxially aligned with the first cylindrical bore;   a first piston operably disposed within the first cylindrical bore; and   a second piston operably disposed within the second cylindrical bore, wherein the first piston and the second piston define the combustion chamber therebetween.   
     
     
         12 . A method for operating an internal combustion engine, the internal combustion engine comprising a desmodromic valve actuation system, the method comprising:
 moving a first rocker arm of the desmodromic valve actuation system to drive a reciprocating sleeve valve away from a valve seat to open a passage in fluid communication with a combustion volume of the internal combustion engine, the reciprocating sleeve valve having a cylindrical bore that at least partially defines the combustion chamber, a reciprocating piston being operably disposed in the cylindrical bore; and   moving a second rocker arm of the desmodromic valve actuation system to drive the sleeve valve toward the valve seat to close the passage.   
     
     
         13 . The method of  claim 12 , wherein moving the sleeve valve away from the valve seat includes driving the sleeve valve with a first cam lobe that moves the first rocker arm, and wherein moving the sleeve valve toward the valve seat includes driving the sleeve valve with a second cam lobe that moves the second rocker arm. 
     
     
         15 . The method of  claim 12 , wherein the passage is an inlet passage configured to introduce a combustible charge into the combustion chamber. 
     
     
         16 . The method of  claim 12 , wherein the passage is an exhaust passage configured to accept exhaust combustion products from the combustion chamber. 
     
     
         17 . The method of  claim 12 , wherein the sleeve valve includes an external flange, wherein operably engaging the first rocker arm with the flange drives the sleeve valve away from the valve seat and wherein operably engaging the second rocker arm with the flange drives the sleeve valve toward the valve seat. 
     
     
         18 . The method of  claim 12 , wherein the desmodromic valve actuation system includes first and second cam lobes, wherein rotating the first cam lobe results in movement of the first rocker arm and drives the sleeve valve away from the valve seat, and wherein rotating the second cam lobe results in movement of the second rocker arm and drives the sleeve valve toward the valve seat. 
     
     
         19 . The method of  claim 12 , wherein the desmodromic valve actuation system includes a camshaft having first and second cam lobes, wherein rotating the first cam lobe results in movement of the first rocker arm and drives the sleeve valve away from the valve seat, and wherein rotating the second cam lobe results in movement of the second rocker arm and drives the sleeve valve toward the valve seat. 
     
     
         20 . The method of  claim 12 , wherein the desmodromic valve actuation system includes:
 a first cam lobe;   a second cam lobe;   wherein the first rocker arm is disposed between the first cam lobe and the sleeve valve, and wherein rotating the first cam lobe causes the first rocker arm to drive the sleeve valve away from the valve seat and open a passage in fluid communication with the combustion chamber; and   wherein the second rocker arm is disposed between the second cam lobe and the sleeve valve, and wherein rotating the second cam lobe causes the second rocker arm to drive the sleeve valve toward the valve seat and close the passage.