Continuously Variable Valve Lift and Duration - VLD

Our variable valve lift system is ideal for advanced combustion strategies.

  • Internal EGR- Re-open the intake or exhaust valves to generate internal Exhaust Gas Re-Circulation.
  • HCCI in diesel engines- Control the complex pressure-temperature-time history within the combustion chamber to enable and extend HCCI operation.
  • Throttle-less operation in gasoline engines- Control intake valve lift, remove the throttle and improve part-load fuel economy from reduced pumping losses. Furthermore, control intake valve duration for improved performance.
  • Secondary valve lift- This is the only cam summing system patented to use controlled secondary valve lifts.
PICTURE:- 3D view of our variable valve lift rocker
PICTURE:- Side on view of a variable lift top rocker
PICTURE:- Another view of our variable valve lift rocker system

Technology Handouts

Please download the following PDFs summarising the benefits of Mechadyne's VLD technology:

Gasoline VLD Diesel VLD

VLD Key Points

  • Simple proven design
  • Excellent valvetrain dynamics
  • Minimal cylinder head alteration
  • No control shaft to package
  • Continuously variable valve lift
  • Upgrade from a finger follower
  • Many VLD strategies
  • Good for HCCI

How Our Variable Valve Lift System Works

VLD uses a rocker system to sum the lifts from two cam profiles. If we change the phase between these two cam profiles, we simultaneously alter the valve lift and duration.

The two cam profiles are mounted on an SCP camshaft. This allows us to continuously control their relative phase without the need for an extra control shaft.

The Upgrade Path

If an engine is designed with provision for VLD, we can run both a VLD valvetrain and a standard finger follower valvetrain in the same cylinder head.

Only the camshafts and valvetrain need to be swapped out to turn a conventional head into a VLD head.

Furthermore, we can switch between any valve lift curve family by a simple cam pofile change.

More info about the upgrade path

VLD Video Media

View these videos to understand more about VLD...

Variable Duration Control

See a kinematic animation of a VLD system designed for duration control.   This animation shows how changing the relative phase of the two cam profiles changes the resultant valve lift profile. duration control kinematics

Variable Lift For Valve Head Load Control

See a kinematic animation of a VLD system designed for valve head load control via variable lift.   This animation shows how changing the cam profiles can produce a completely different set of valve lift curves. duration control kinematics

Second Lift With Duration Control

See a kinematic animation of a VLD system designed for compound control of valve duration and seconary lift.   This animation shows how a further cam profile change can enable relatively complex lift strategies.  This profile would be suitable for an intake camshaft, where we have a variable pre-opening for generating internal EGR and variable intake valve closing for control of effective compression ratio. scond lift and duration control kinematics

VLD Camshaft Assembly

See the fundamental elements of the variable lift camshaft assembly and how they go together and operate. VLD camshaft assy

Lift Curve Families

See all the different valve lift curve families that are possible using a single VLD system.   We only need to change the cam profile to switch between these families. VLD valve lift curves and strategies

Test Cell Laser Readout

See VLD in action with real-time laser readouts from our test cell. Duration Control Second Lift