CLOSER TO THE PERFECT ENGINE
Valve control is set to change with the arrival of infinitely variable valves
IMAGINE A VALVE control system without compromises, one that isn’t crank-driven and doesn’t play by conventional rules. Such an engine would allow infinitely variable timing on all its valves, independent of one another, meaning it could effectively tune itself on the move, boosting power and efficiency. It could also offer cylinder deactivation, eliminate a turbocharger’s wastegate, switch between four- and two-stroke cycles and even run as an ingenious, very efficient 12-stroke.
Camcon, a UK-based firm, is working on intelligent valve actuation (IVA), which has big component manufacturers interested, and is predicted to reach mainstream production within five years.
How does it work? IVA employs an independently driven camshaft for each conventional engine valve via a desmodromic linkage. All aspects of the valve timing are independently and infinitely variable, with full feedback control, allowing valve lift, duration, and timing to be adjusted independently of each other. In other words, a lot more than currently possible with crank-driven camshafts.
Because it’s an active system, Camcon’s Roger Stone explains: “It could unlock homogeneous charge compression ignition (a very efficient, diesellike combustion process) and both the Miller and Atkinson cycles respond well to IVA.”
Working on the inlet cam side only, it has improved a Jaguar Ingenium engine’s efficiency by 7.5 per cent, and a non-VVT engine’s by 10.5, with room for further improvement in varied conditions.
And that 12-stroke system we mentioned? In motorway cruising, every cylinder fires only every third stroke, which is potentially cleaner than cylinder deactivation since there are no CO2 spikes as cylinders are reactivated. Nifty.