Unique engine control possibilities: 

Reverse Rotation.  The DEVAS^TM ECU can identify reverse engine rotation should the engine accidently rotate backward, (if parked on a hill or during a misfire at startup).  These conditions occur only occasionally, but in all cases, valves must be closed when the piston is at or near TDC (top dead center) to prevent engine damage.  Note that reverse engine rotation is desirable in marine applications when two engines are installed side-by-side.  The DEVAS^TM ECU can be easily programmed to allow for reverse rotating engines.

Combustion Swirl:  Modern engines use four valves per cylinder to save energy and provide higher engine RPM.  Control of the extra two valves may be accomplished by duplicating valve drivers for the second two valves, or by duplication of the comparator circuitry for the first set of valves (timing for the additional two valves can then be independent).  This duplication allows the control computer to introduce a slight delay for the second two valves, (this different intake/exhaust valve timing induces a swirling motion inside the cylinder--enhancing the burning process). 

Idle & Braking Control:  For low speed or low torque operation, the second intake/exhaust valves may be left closed to conserve energy.  The first intake valve may also be used to perform throttle control by opening for only a very short duration (as when idling).  Safe, clean, engine braking is also possible with electrical valve/fuel injection control (Jake brake).  Many possibilities exist with electrically controlled valves.

Limp Home Mode:  All registers are loaded at power-up with default running values.  This allows for a limp-home engine operation if the engine control computer fails.

2 or 4 Cycle Operation:  DEVAS^TM allows variable valve timing such that the engine may be operated under 2 or 4 cycle modes as well as transition between 2 and 4 cycle modes.

Eliminate the Throttle:  by controlling valve duration from its short idle duration to its maximum torque duration, the engine can be effectively “throttled” without the necessity of a mechanical throttle butterfly.

Power Bursts:  using the stored energy in the accumulator, the engine can be immediately accelerated (no need to wait for engaging the hydraulic pump).

INTERNAL Exhaust Gas Recirculation (EGR) Control:  intake valves can be “dithered” during the exhaust sequence to port exhaust gases back through the combustion chamber.  Similarly, exhaust valves can be “dithered” during the intake sequence to promote scavenging.

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2)  Electro-hydraulic Engine Valve Control System:

DEVAS^TM provides engine valve motion by combining a three way electrically operated Dual Solenoid valve with an axial hydraulic Acutator.  A typical sequence begins with the engine valve closed and the Actuator ported to “sump.”  When commanded to “open” by the Engine Control Unit (ECU), the “open” solenoid’s electro-magnetic force shuttles its internal sleeve allowing high pressure oil to flow and pressurize the Actuator pisiton.  The piston is aligned axially with the engine valve and as the piston moves, the valve spring is compressed until an internal mechanical stop is reached.  At this point the engine valve is fully open.  The valve is closed by the force of the compressed valve spring.  The second solenoid coil is given a “close” pulse and the spool vents the actuator to sump.  Each of the individual valve actuators contain end of stroke, dampers.  These are used to bring the engine valves to a soft landing when re-seating.

The system requires minimal electric power since the Solenoid valve is a latching type.  Thus, only a command “OPEN” pulse is required to initiate the flow of pressurized fluid.  Similarly, a second electrical command “CLOSE” pulse shuttles and latches the internal sleeve such that the volume of high pressure fluid that opened the engine valve is now ported to sump.  The engine valve is returned to its seat by a standard automotive valve spring.   The spring simultaneously returns the hydraulic piston and its oil is drained to sump.  To reduce operational noise, the hydraulic piston incorporates a damping port which slows the piston as it nears its closed position.  Engine valve seating follows this same velocity profile resulting in soft seating with minimal noise.

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3)  Hydraulic Supply System:

          A DEVAS^TM system provides the typical engine management functions of fuel injection and spark timing and uses standard automotive sensors.  DEVAS^TM is also functional with newer CAN 2.0A/2.0B bus systems.  What DEVAS^TM adds is the ability to control opening and closing events of Intake and Exhaust Valves and to calculate these events prior to revolution.

          To affect variable valve control, the camshsfts and rocker arms are replaced by a hydraulic valve / actuator system.  The basic components are shown below:

 DEVAS^tm

               Digital Electro-hydraulic Valve Actuation System

          The hydraulic system may use the existing engine oil with expanded sump volume, or a completely independent fluid system.  Oil is pressurized by an engine driven commercial pump.  Pressure is a system design variable.  At 3000 psi the system is smaller and capable of higher rpm, but lower pressures (1500 - 500 psi) are recommended.  The Accumulator provides stored fluid energy for power bursts.  An Unloader valve saves on system energy consumption since the pump can be cyclically bypassed when demands are low.

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SPECIFICATIONS FOR:

  DEVAS^tm

Digital Electro-hydraulic Valve Actuation System

CAMLESS ENGINE CONTROLLER

OUTPUTS:

         8 Ignition Coil outputs - configured as twin plug or sequential

         8 Fuel Injector outputs 

         64 Valve Drivers - 32 open & 32 close

DECODER:

         360 counts per revolution

         1/3 degree accuracy & 1/4 degree resolution in real-time

         0-25,000 rpm

         Works for CW or CCW rotation

         Injectors inactive if engine rotates backward

         Suitable for 2, 3, 4, 5, 6, 8, 10, 12, or 16 cylinder engines

MICRO CONTROLLER:

         Siemens 167 based w/ CAN bus

         16 channels, 10 bit A-D converter

         Language: C & native instruction set

         Over 100 I/O points available

GRAPHICAL USER INTERFACE:

         RS-232/RS-485 optional or CAN

         Runs in 32 bit Windows 95, 98, 2000 or XP

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