Reciprocating expander valve operating apparatus, system and method

Abstract

The disclosure describes a method to operate a conventional 4 cylinder engine as an expander for any pressurized fluid (e.g., liquid, vapor, or gas). A poppet valve system is disclosed enabling upward lift of the inlet valve, with assist from cylinder compression pressure, together with downward lift from an exhaust valve, resulting in especially efficient expansion of fluid or gas in a thermodynamic power cycle. Further, it is described that a desmodromic valve operation system may be employed and provides essential guidance and opening closing actions for proper operation of the expander system.

What is claimed is: 
     
         1 . A method of operating a reciprocating expansion device, the expansion device comprising at least one expansion chamber with a reciprocating element, a inlet to the expansion chamber with at least one outward opening inlet valve, and an exhaust from the expansion chamber having at least one inward opening outlet valve, the method comprising:
 providing pressurized working fluid to the inlet;   opening the inlet valve in the outward directed to deliverer pressurized working fluid to the expansion chamber to expand and to drive a motion of the reciprocating element; and   opening the outlet valve in the inward direction to allow expanded working fluid to escape the expansion chamber to the exhaust.   
     
     
         2 . The method of  claim 1 , further comprising:
 opening and closing the inlet and outlet valves using a desmodromic cam device, said cam device applying force during both opening and closing movements of the inlet and outlet valves.   
     
     
         3 . The method of  claim 2 , wherein each of the inlet and outlet valves is opened and closed without the use of a spring closure mechanism. 
     
     
         4 . The method of  claim 1 , comprising:
 using an exhaust stroke of the reciprocating element to drive expanded working fluid out through the outlet valve; and   using pressure generated in the expansion chamber during the exhaust stroke to apply an outward force to the inlet valve to assist in opening the inlet valve;   wherein the pressure generated in the expansion chamber during the exhaust is greater than the pressure at the inlet on a side external to the expansion chamber.   
     
     
         5 . The method of  claim 4 , wherein the applied outward force on the inlet valve reduces an inlet valve cam opening force on a cam used to open the inlet valve. 
     
     
         6 . The method of  claim 5 , comprising generating pressure in the cylinder to a required value by controlling of the point of closure of the exhaust valve. 
     
     
         7 . The method of  claim 4 , wherein the opening of the inlet valve is accomplished using only the outward force to the inlet valve, generated by a recompression pressure in the cylinder. 
     
     
         8 . The method of  claim 7 , wherein the inlet valve does not have an associated opening cam. 
     
     
         9 . The method of  claim 1 , wherein the inlet valve comprises one or more mechanical latches, the method comprising:
 using at least one mechanical latch to hold the inlet valve in a stable open or a stable closed position during at least a portion of an operating cycle of the expansion chamber.   
     
     
         10 . The method of  claim 9 , comprising:
 during a first portion of the operating cycle, using the internal pressure of the expansion chamber to move the inlet valve outward towards a fully open position;   using at least one mechanical opening latch to hold the in the fully open position.   
     
     
         11 . The method of  claim 10 , comprising:
 using the operation of the opening latch to provide a force which assists in moving the inlet valve towards the fully open position.   
     
     
         12 . The method of  claim 1 , wherein:
 the inlet valve comprises a mechanical latch and a spring mechanism, and wherein the method comprises:
 during a first portion of an operating cycle of the expansion chamber, using the mechanical latch to maintain the inlet valve in a closed position; 
 during a second portion of the operating cycle, releasing the latch, and using pressure inside the expansion chamber to open the inlet valve; and 
 using the spring mechanism to return the inlet valve from the open position to the closed position. 
   
     
     
         13 . The method of  claim 10 , wherein the inlet valve is opened using the pressure inside the expansion chamber without the assistance of a force from an opening mechanism located external to the expansion chamber. 
     
     
         14 . The method of  claim 1 , wherein the inlet valve comprises at least one electromagnet, the method comprising:
 controlling the electromagnet to actuate the inlet valve between a substantially stable open position and a substantially stable open position.   
     
     
         15 . The method of  claim 14 , wherein the at least one electromagnet comprises at least a first and a second electromagnets, the method comprising:
 switching the first electromagnet to an on state and the second electromagnet to an off state to maintain the inlet valve in the stable open position; and   switching the first electromagnet to an off state and the second electromagnet to an on state to maintain the inlet valve in the stable closed position.   
     
     
         16 . The method of  claim 1 , wherein the inlet valve comprises an over-center toggle mechanism having a stable closed and a stable open position, wherein the method comprises:
 during a first portion of the operating cycle of the expansion chamber, using the internal pressure of the expansion chamber to toggle the inlet valve from the stable closed position to the stable open position.   
     
     
         17 . The method of  claim 16 , further comprising:
 during a second portion of the operating cycle, using a mechanism external to the expansion chamber to toggle the inlet valve into the stable closed position.   
     
     
         18 . The method of  claim 1 , wherein the inlet valve comprises a spring loaded cam driven toggle mechanism, the method comprising:
 placing the valve in a closed position by seating a valve body against a seal, thereby causing a build up of pressure in the inlet to the expansion chamber; and   rotating a cam to drive the toggle mechanism to apply an opening force on the valve body to unseat it from the seal, thereby placing the expansion chamber in fluid communication with the inlet and causing a reduction in inlet pressure.   
     
     
         19 . The method of  claim 1 , wherein the reciprocating expansion device comprises:
 a primary expansion chamber with a primary reciprocating element, and   a secondary expansion chamber with a secondary reciprocation element,   the method comprising:   using fluid exhausted from the primary expansion chamber to drive the operation of the secondary expansion chamber.   
     
     
         20 . An apparatus comprising a reciprocating expansion device comprising:
 at least one expansion chamber with a reciprocating element,   an inlet to the expansion chamber with at least one outward opening inlet valve and configured to receive a pressurized working fluid, and   an exhaust from the expansion chamber having at least one inward opening outlet valve;   and a valve drive system configured to:
 open the inlet valve in the outward directed to deliver pressurized working fluid to the expansion chamber to expand and to drive a motion of the reciprocating element; and 
 open the outlet valve to allow expanded working fluid to escape the expansion chamber to the exhaust.