ELECTRONICALLY VARIABLE VALVE TIMING

A PROGRAM IS PROPOSED TO ANALYZE, DESIGN AND TEST COMPONENTS FOR A SYSTEM THAT WILL OPERATE THE VALVES OF 4-CYCLE DIESEL AND GASOLINE ENGINES BY MEANS OF HYDRAULIC ACTUATORS, ELECTRONICALLY CONTROLLED. THE CONCEPT EMPLOYS A FEEDBACK POSITION TRANSDUCER THAT PROVIDES A SIGNAL EMPLOYED TO COMPARE ACTUAL VALVE DISPLACEMENT WITH A PROGRAMMED DISPLACEMENT AND TO MAKE APPROPRIATE ADJUSTMENTS IN THE POSITION OF A HYDRAULIC FLOW CONTROL VALVE SO THAT ENGINE VALVE TRAVEL ACHIEVED CORRESPONDS TO TRAVEL DESIRED. THE DESIRED OPENING PROGRAM WILL BE VARIED BY SELECTION FROM A RANGE OF SUCH PROGRAMS HELD IN A MICROPROCESSOR AND ACCESSED BY COMBINATIONS OF OPERATING CONDITIONS OF THE ENGINE. THESE PROGRAMS CAN INCLUDE VARIABLE OVERLAP SETTINGS THAT ARE SELECTED BY SPECIFIC COMBINATIONS OF SPEED AND LOAD, TRANSIENT RESPONSE BOOSTER FOR TURBOCHARGED ENGINES, COMPLETE CYLINDER SHUT DOWN FOR IDLE ON HALF THE NUMBER OF CYLINDERS, ZERO OVERLAP FOR COLD STARTING, PARTIAL EXHAUST VALVE OPENING FOR IMPROVED ENGINE BRAKING AND THROTTLE ELIMINATION ON SPARK IGNITED ENGINES. ONCE THE PRINCIPLE OF OPERATING IN RESPONSE TO A MEMORY HELD PROGRAM HAS BEEN REALIZED, ALL THESE FUNCTIONS MAY FOLLOW MERELY BY THE PROGRAMMING PROCESS. A CRITICAL COMPONENT IN THE PROOF OF CONCEPT IS THE PERFORMANCE OF THE HYDRAULIC CONTROL VALVE. FOR THIS REASON A PROTOTYPE OF THE VALVE WILL BE DETAILED DESIGNED AND FABRICATED. AN EXISTING IN-HOUSE POWER SUPPLY WILL BE EMPLOYED TO PRODUCE PRELIMINARY PERFORMANCE DATA ON THIS UNIT.