White Papers:

SAE Paper: “Experimental Comparison of a Rotary Valvetrain on the Performance and Emissions of a Light Duty Spark Ignition Engine”

SAE – Japan: “Development of a Rotary Valve Engine…”

ASME: “A CFD Investigation…Alternative Valvetrain”

Our Technology

Vaztec’s oil-free, rotating valvetrain technology, ECORev, eliminates all reciprocating parts in the valvetrain  assembly. Simplified rotating valves replace the camshaft, lifters, pushrods, rocker arms, poppet valves, keepers and related parts.

ECORev technology has been successfully integrated and tested in multiple prototypes demonstrating performance, durability and scalability.


Superior Gas Exchange

  • Improved volumetric efficiency
  • Improved filling and trapping
  • Increased combustion turbulence
  • Improved exhaust flow

A rotary valve is an alternative design to the traditional poppet valve and is used for controlling the intake and exhaust processes in a 4-Stroke engine.

    • As depicted in the photos below, a simple shaft with a slot cut across its axis provides a flow path for the intake charge or exhaust gases.

    • As the rotary valve is turned (rotated), the slots are exposed to ports in the cylinder head that allow the intake charge into the cylinder or allow exhaust gases to escape.
    • The valve’s rotation is timed to the crankshaft, just as a camshaft may be, to create the desired valve timing events.

    Prototype intake valve (not optimized for production]

    Cylinder head exposed to show a prototype dual-port valve (intake & exhaust)

    Rotary valves can provide very efficient cylinder filling and mixing largely due to the resulting tumble effect demonstrated through our CFD analysis.  This behavior results in improved speed of combustion as measured in our working prototypes.


    Unimpeded Flow 

    Restricted Flowpath

    As can be seen in the graphic below, the rotary valve has the capability to have very high discharge coefficients (the ratio of actual flow to perfect flow) when it approaches the fully open position. This is much higher than is possible with even the most advanced poppet valves. The result is more efficient air/fuel mixture filling and exhaust at all engine speeds.

    Vibration and Noise Testing (3rd party instrumentation and analysis)



    End Product Benefits (targeted)

    Improved and extended performance with reduced emissions and fuel usage


    Greatly improved flow


    High in-cylinder turbulence


    Increase combustion speed


    Lean burn capabilities

    Low vibration & noise


    Simple rotational motion


    Elimination of reciprocating parts


    No cam-to-tappet noise


    Reduced harmonics

    Reduced cost & maintenance


    Simplified valvetrain, low part count


    Oil-free valvetrain (cylinder head)


    Eliminates risk of piston-valve contact


    Elimination of valve adjustment & valve seat recession


    A rotary valve engine can be used in any market that are currently served by internal combustion engines. This type of valve provides engine designers a way to make a more powerful engine in the same package size. The power delivery of rotary valve engines provides broad, usable torque, applicable to multiple applications.