ASK KEVIN: Will Motorcycles Get Pneumatic Valve Actuators?

Koenigsegg One:1 studio 3/4 view

Koenigsegg One:1

QUESTION: I've read and heard much about pneumatic valve actuators from people like supercar manufacturer Christian von Koenigsegg, and I am intrigued. These are not pneumatic valve springs as are already in use in MotoGP and F1, but would be a replacement for the camshaft itself. The possibilities seem fantastic; things like infinitely and dynamically variable cam profiles and timings would only be the beginning. Is this a technology that is likely to find its way into motorcycle racing or to the street?

Nathan Gooch

ANSWER: Continuously variable valve timing and lift is the Holy Grail of auto engine design, for it could eliminate the compromise valve timings that require us to give up bottom torque to make top power, or to give up top power to make bottom torque. Such a variable timing system also could allow engines to safely operate at more fuel-efficient higher compression ratios through the Atkinson Cycle, or other schemes that can make an engine's expansion ratio higher than its compression ratio.

Many varieties of variable valve-timing actuators are possible—electromagnetic, hydraulic, hydropneumatic, etc, but all must solve the problem of survivable valve seating. Valve seating velocity must be kept below a few inches per second or the accumulated damage of many hard seatings will either break the valve or cause rapid seat and valve sealing surface wear. I suspect that the Koenigsegg/Cargine system includes some kind of hydraulic seating control.

Koenigsegg videos show us various generations of actuator at work, with oscilloscope displays of the valve motion, velocity, etc. We are shown a Saab automobile, which we are told has done considerable mileage with the various generations of Cargine actuator. This is interesting but does not answer the questions that must be asked by automotive manufacturers.

The problem of the automakers is to produce at saleable cost durable engines that will sell in the marketplace while offering the capability of continuously adapting to the present and future demands of government regulatory agencies.

We have all seen the various liquids (old-timers called them “motor honey”) advertised, which are claimed to bring the usual benefits in power, fuel consumption, and emissions when poured into engine oil or fuel. As we read the label, we know that automakers spend millions to achieve fractional mpg gains that will save them from fines imposed for failure to meet CAFÉ standards. Why, if the miracle liquids can indeed “improve fuel economy up to 30 percent,” are their makers selling the stuff to us at $10 a bottle when they could be paid millions by a grateful auto industry?

The answer is in the words: "up to 30 percent.” The words mean, literally, that the miracle liquid can improve fuel economy by some amount from zero to 30%. The auto industry tests everything, but is not paying millions for zero improvement.

You can be sure that the auto industry is very interested in continuously variable valve timing, and it will be adopted because of its potential benefits as soon as it demonstrates a positive cost-to-benefit ratio and equals the reliability of current systems.

Who knows? Maybe Mr. Koenigsegg is now inking a huge deal with Toyota. Until such a thing happens, these systems are big (but interesting) question marks.

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