Variable engine valve control system

Abstract

A variable engine valve control system wherein each of the reciprocating intake and/or exhaust valves is hydraulically controlled and includes a piston subjected to fluid pressure acting on surfaces at both ends of the piston. The space at one end of the piston is connected to a source of high pressure fluid while the space at the other end is connected to a source of high pressure fluid and a source of low pressure fluid, and disconnected from each through action of controlling means such as solenoid valves. The controlling means may include a rotary hydraulic distributor coupled with each solenoid valve, thereby permitting each solenoid valve to control operation of a plurality of engine valves in succession. Equal air delivery to all engine cylinders having the aforementioned variable valve control system is assured by controlling electric pulses of variable duration and timing, the system involving means for making individual modifications of the durations of the electric pulses controlling each individual actuator, and the modifications being of such nature as to assure that all actuators control the engine intake (or exhaust) valves in an identical manner to assure equal valve strokes in all cylinders.

IWe claim:  
     
       1. A hydraulically operated valve control system for an internal combustion engine, said system comprising: 
       a high pressure source of fluid and a low pressure source of fluid;  
       a cylinder head member adapted to be affixed to the engine and including an enclosed cavity;  
       a poppet valve shiftable between a first and second position within said cylinder head member;  
       a hydraulic actuator including a piston coupled to the poppet valve and reciprocable within the enclosed cavity which thereby varies in displacement as the poppet valve moves;  
       said cylinder head member having a high pressure port extending between the enclosed cavity and the high pressure source of fluid and a low pressure port extending between the enclosed cavity and the low pressure source of fluid;  
       a high pressure valve and a low pressure valve for respectively regulating the flow of fluid in the high pressure and the low pressure ports; and  
       control means cooperating with the high and low pressure valves for selectively coupling the enclosed cavity to the high pressure and low pressure sources to oscillate the poppet valve in timed relation to engine operation, wherein during each oscillation, some of the high pressure fluid used to reciprocate the poppet valve is returned to the high pressure source, thereby allowing that the net fluid flow between the high pressure and low pressure sources may be substantially less than the volume swept by the piston.  
     
     
       2. The system of claim I wherein the area subject to fluid pressure on one side of the said piston is larger than the area subjected to fluid pressure on the other side of the piston; 
       said poppet valve accelerating in the direction of poppet valve opening when the control means opens the high pressure valve and decelerating when the high pressure valve closes;  
       said poppet valve accelerating in the direction of poppet valve closing when the control means opens the low pressure valve and decelerating when the low pressure valve closes;  
       the timing of the high pressure valve opening controlling the timing of the poppet valve opening, and the timing of the low pressure valve opening controlling the timing of the poppet valve closing; and  
       the duration of the high pressure valve opening controlling the poppet valve stroke.  
     
     
       3. The system of  claim 1  wherein the high pressure valve and the low pressure valve are solenoid valves. 
     
     
       4. The system of  claim 1  wherein said piston includes a pair of ends exposed to opposite respective ends of the enclosed cavity; 
       said high pressure source includes a first high pressure fluid line leading to the enclosed cavity at both ends of the piston;  
       said high pressure valve being located within said first high pressure line and operational to open and close fluid flow to one end of said piston;  
       the other end of said piston being continuously open to said high pressure fluid source;  
       a low pressure fluid line leading to the enclosed cavity at said one end of the piston, the low pressure valve being located within said low pressure line and operational to open and close fluid flow to the one end of the piston; and  
       a normally closed pressure relief valve located in the low pressure line intermediate the one end of said piston and the low pressure valve, whereby during the opening and closing of the poppet valve, the potential energy of the fluid from the high pressure fluid source can be utilized to accelerate the poppet valve, thereby increasing the kinetic energy of the poppet valve, and, during deceleration, the kinetic energy of the poppet valve can be utilized to pump the fluid back into the high pressure fluid source, thereby restoring the potential energy of the high pressure fluid.  
     
     
       5. The system of  claim 4  wherein said high pressure source includes a second high pressure fluid line hydraulically coupled to said one end of the piston, and a normally closed pressure relief valve located in the second high pressure fluid line. 
     
     
       6. The system of  claim 5  including a pair of said poppet valves, each poppet valve including one said hydraulic actuator and a respective one said high pressure relief valve and one said low pressure relief valve; 
       said first high pressure fluid line and said low pressure fluid line each being hydraulically coupled to each said poppet valve and hydraulic actuator;  
       said control means including a pair of control valves, one each being hydraulically coupled to a respective first high pressure fluid line and low pressure fluid line intermediate the pair of poppet valves whereby when the control valves are open, both poppet valves are operational and when the control valves are closed, only one poppet valve is operational.  
     
     
       7. The system of  claim 5  including a plurality of said poppet valves, each poppet valve including one said hydraulic actuator and a respective one said high pressure relief valve and one said low pressure relief valve; 
       said control means including a high pressure fluid distributor means interposed between said high pressure valve and each said first high pressure fluid line leading to each said poppet valve and having a separate outlet port to each said first high pressure fluid line, said high pressure fluid line means being selectively controllable in timed sequence to conduct high pressure fluid to any one of said poppet valves when said high pressure valve is open;  
       said control means further including a low pressure fluid distributor means interposed between said low pressure valve and each said low pressure fluid line leading to each said poppet valve and having a separate outlet port to each said low pressure fluid line, said low pressure fluid line means being selectively controllable in timed sequence to conduct low pressure fluid to any one of said poppet valves when said low pressure valve is open;  
       whereby a single high pressure valve and a single low pressure valve can be utilized to control the actuation of a plurality of poppet valves to be sequentially operated.  
     
     
       8. The system of  claim 7  wherein said high pressure distributor means and said low pressure distributor means each comprise: 
       a rotary distributor valve;  
       the rotary distributor valve comprising a stationary outer sleeve and a rotatable inner distributor sleeve concentrically arranged within and in sliding engagement with said outer sleeve;  
       said inner distributor sleeve having an inlet port at one end and a drive shaft at the opposite end; and  
       said high and low pressure valves being hydraulically coupled to a respective said inlet port to control fluid flow through the rotary distributor valve.  
     
     
       9. The system of  claim 1  further including means for converting the potential energy of the fluid into kinetic energy of the reciprocating poppet valve during the poppet valve acceleration and then similarly converting the kinetic energy of the poppet valve into potential energy of the fluid during the poppet valve deceleration. 
     
     
       10. The system of  claim 1  wherein the high pressure and the low pressure sources of fluid comprise a respective container filled with pressurized fluid whereby inflow of the fluid into the hydraulic actuator is the result of the fluid expansion from a respective one of the pressurized containers, and outflow of the fluid through said high pressure and low pressure valves increases fluid compression in each respective pressurized container. 
     
     
       11. In an internal combustion engine, an engine valve control system in which the valve stroke is controlled by varying timing and duration of electric signals sent to individually dedicated engine valve controlling means, the system comprising: 
       a controller programmed to send variable electric control signals to the said engine valve controlling means, said control signals duration comprising the algebraic sum of a basic signal duration and a correction signal duration;  
       means for generating a basic signal duration determined by the controller as a function of engine operating conditions and being equal for all engine intake valves and equal for all engine exhaust valves; and  
       means for generating a correction signal predetermined for each of the engine valve controlling means as a measure of the extent the performance of each engine valve controlling means varies from a predetermined standard, said correction signal generating means being operative in timed sequence to supply to the controller said predetermined correction signal just prior to a respective engine valve controlling means being activated.  
     
     
       12. The system of  claim 11  wherein said correction signal generating means comprises: 
       a rotatable member having individual codings thereon in spaced sequence, each coding representing a specific engine valve controlling means and containing information on the correction signal required by the said specific engine valve controlling means; and  
       a sensor installed in proximity of the said rotatable member, said sensor being capable of reading the information contained in each coding on the rotatable member as it passes the sensor and transmitting said reading as a correction signal to said controller.  
     
     
       13. The system of  claim 12  wherein each said coding is in the form of a tag and each tag is affixed to said rotatable member; 
       means for rotating said rotatable member during engine operation with an angular velocity equal to half the crankshaft velocity on a four-stroke engine and equal to crankshaft velocity on a two-stroke engine, whereby said sensor will read the information on individual tags successively passing the proximity of the sensor and transmit a respective correction signal to the controller, the location of individual tags on said rotatable member being such that the information on each tag is read and sent to the control system just before the engine valve controlling means for which the tag was coded must be actuated.  
     
     
       14. The system of  claim 11  further including: 
       a high pressure source of fluid and a low pressure source of fluid;  
       a cylinder head member adapted to be affixed to the engine and including a plurality of enclosed cavities;  
       a plurality of poppet valves, each being associated with a respective one of said plurality of enclosed cavities;  
       each said poppet valve being shiftable between a first and second position within said cylinder head member;  
       a hydraulic actuator including a piston coupled to each said poppet valve and reciprocable within the respective enclosed cavity which thereby varies in displacement as each poppet valve moves;  
       said cylinder head member having a high pressure port extending between the enclosed cavities and the high pressure source of fluid and a low pressure port extending between the enclosed cavities and the low pressure source of fluid;  
       a high pressure valve and a low pressure valve for respectively regulating the flow of fluid in the high pressure and the low pressure ports of each of said plurality of enclosed cavities;  
       control means cooperating with the high and low pressure valves for selectively coupling the enclosed cavities to the high pressure and low pressure sources to oscillate each poppet valve in timed relation to engine operation, wherein during each oscillation, some of the high pressure fluid used to reciprocate the poppet valve is returned to the high pressure source;  
       said control means including means for controlling (i) the motion of each said poppet valve by varying the timing and duration of the said control means actuation, (ii) the timing of the valve opening and closing motions of each poppet valve by varying the timing of said control means actuation, and (iii) the stroke of each said poppet valve by varying the duration of said control means actuation; and  
       means for varying the pressure of the pressure of the pressurized fluid whereby the acceleration, velocity and travel time of each poppet valve may also be controlled.  
     
     
       15. The system of  claim 14  wherein said control means includes said individual engine valve controlling means for each said poppet valve, whereby the duration of the control signal may be individually adjusted for each engine valve controlling means in all cylinders so as to assure equal poppet valve strokes in all cylinders. 
     
     
       16. A hydraulically operated valve control system for an internal combustion engine, said system comprising: 
       
         a high pressure source of fluid and a low pressure source of fluid;  
       
       
         a cylinder head member adapted to be affixed to the engine and including an enclosed cavity:  
       
       
         a poppet valve shiftable between a first and second position within said cylinder head member;  
       
       
         a hydraulic actuator including a piston coupled to the poppet valve and reciprocable within the enclosed cavity which thereby varies in displacement as the poppet valve moves;  
       
         said cylinder head member having a high pressure port extending between the enclosed - cavity and the high pressure source of fluid and a low pressure port extending between the enclosed cavity and the low pressure source of fluid;    
       
         a high pressure valve and a low pressure valve for respectively regulating the flow of fluid in the high pressure and the low pressure ports; and  
       
       
         control means cooperating with the high and low pressure valves for selectively coupling the enclosed cavity to the high pressure and low pressure sources to oscillate the poppet valve in timed relation to engine operation, wherein during each oscillation, some of the high pressure fluid used to reciprocate the poppet valve is returned to the high pressure source. 
       
     
     
       17. A valve system comprising: 
       
         a valve having a first plunger surface and a second plunger surface, said valve being displaceable between a first position and a second position;  
       
       
         a source of relatively low pressure fluid;  
       
       
         a source of relatively high pressure fluid;  
       
       
         means for selectively communicating fluid between said first plunger surface and said high pressure fluid source;  
       
       
         said first plunger surface being operable to urge said valve toward said second position when said first plunger surface is in fluid communication with said high pressure fluid source; and  
       
       
         said first plunger surface being operable to return fluid to said high pressure fluid source when said valve moves from said second position toward said first position. 
       
     
     
       18. The valve system as claimed in  claim 17 , wherein said valve system further comprises means for biasing said valve toward said first position comprising a source of said high relatively high pressure fluid in continuous communication with said second plunger surface. 
     
     
       19. A method of operating a valve system having a high pressure fluid source and having a valve having a first plunger surface and a second plunger surface and being displaceable between a first position and a second position, comprising the steps of: 
       
         communicating high pressure fluid with said first plunger surface of said valve while said valve is at the first position;  
       
       
         displacing said valve in a first direction from said first position toward said second position in response to said high pressure fluid being in communication with said first plunger surface;  
       
       
         maintaining fluid communication between said high pressure fluid and said first plunger surface during a first portion of displacement of said valve from said first position toward said second position;  
       
       
         prior to said valve reaching said second position, ceasing communication of said high pressure fluid with said first plunger surface which in conjunction with said high pressure fluid acted to displace said valve in said first direction, whereupon said valve continues moving toward said second position; and  
       
       
         during displacement of said valve from said second position toward said first position and prior to said valve returning fully to said first position returning fluid under pressure to said high pressure fluid source. 
       
     
     
       20. A method of operating a valve system having a high pressure fluid source and having a valve having a first plunger surface and a second plunger surface and being displaceable between a first position and a second position comprising the steps of: 
       
         communicating high pressure fluid with said first plunger surface of said valve while said valve is at the first position;  
       
       
         displacing said valve in a first direction from said first position toward said second position in response to said high pressure fluid being in communication with said first plunger surface;  
       
       
         maintaining fluid communication between said high pressure fluid and said first plunger surface during a first portion of displacement of said valve from said first position toward said second position;  
       
       
         prior to said valve reaching said second position, ceasing communication of said high pressure fluid with said first plunger surface which in conjunction with said high pressure fluid acted to displace said valve in said first direction, whereupon said valve continues moving toward said second position; and  
       
       
         during displacement of said valve from said second position toward said first position and prior to said valve returning fully to said first position, communicating high pressure fluid with said first plunger surface which acts to return fluid under pressure to said high pressure fluid source. 
       
     
     
       21. A hydraulically operated valve control system for an internal combustion engine, said system comprising: 
       
         a high pressure source of fluid and a low pressure source of fluid;  
       
       
         a cylinder head member adapted to be affixed to the engine and including an enclosed cavity;  
       
       
         a valve shiftable between a first and second position within said cylinder head member;  
       
       
         a hydraulic actuator including a piston coupled to the valve and reciprocable within the enclosed cavity, said piston having a first end and a second end;  
       
       
         said cylinder head member having a high pressure port between the enclosed cavity and the high pressure source of fluid and a low pressure port between the enclosed cavity and the low pressure source of fluid;  
       
       
         a high pressure valve and a low pressure valve for respectively regulating the flow of fluid through the high pressure and the low pressure ports; and  
       
       
         control means cooperating with the high and low pressure valves for selectively coupling the enclosed cavity to the high pressure and low pressure sources to oscillate the valve in timed relation to engine operation, wherein during each oscillation, some of the high pressure fluid used to reciprocate the valve is returned to the high pressure source, thereby allowing that the net fluid flow between the high pressure and low pressure sources is less than the volume swept by the piston. 
       
     
     
       22. The system of  claim 21  wherein the area subjected to fluid pressure on said first end of said piston is larger than the area subjected to fluid pressure on said second end of the piston; 
       
         said valve accelerating in the direction of valve opening when the control means opens the high pressure valve and decelerating when the high pressure valve closes;  
       
       
         said valve accelerating in the direction of valve closing when the control means opens the low pressure valve and decelerating when the low pressure valve closes;  
       
       
         the timing of the high pressure value opening controlling the timing of the valve opening, and the timing of the low pressure valve opening controlling the timing of the valve closing; and  
       
       
         the duration of the high pressure valve opening controlling the valve stroke. 
       
     
     
       23. The system of  claim 21  wherein said first end of said piston and said second end of said piston are exposed to opposite respective ends of the enclosed cavity; 
       
         said high pressure source includes a first high pressure fluid line communicating with the enclosed cavity at both said first end of the piston and said second end;  
       
       
         said high pressure valve being located within said first high pressure line and between said high pressure fluid source and said enclosed cavity, and being operational to open and close, thereby controlling fluid flow to said first end of said piston;  
       
       
         said second end of said piston being continuously open to said high pressure fluid source;  
       
       
         a low pressure fluid line communicating with the enclosed cavity at said first end of the piston, the low pressure valve being located within said low pressure line and between said low pressure fluid source and said enclosed cavity, and being operational to open and close, thereby controlling fluid flow to said first end of the piston; and  
       
       
         a normally closed pressure relief valve located in the low pressure line between the enclosed cavity and the low pressure valve;  
       
       
         whereby during the opening and closing of the valve, the potential energy of the fluid from the high pressure fluid source can be utilized to accelerate the valve, thereby increasing the kinetic energy of the valve, and, during deceleration, the kinetic energy of the valve can be utilized to pump the fluid back into the high pressure fluid source, thereby restoring the potential energy of the high pressure fluid.