Comments on: Variable Duration Camshafts

By: JC Biggs

JC Biggs — Wed, 21 Jul 2010 00:34:35 +0000

I need this for my drag bike like yesterday. I sent him an email, hopefully we can work something out. I have already got MMC pistons, a air spring valve setup is in the works and a i “obtained” motogp stlye throttle bodies. this would COMPLETE my goal of “worlds most advanced and powerful GSXR1000 Engine.”

By: Danny Williams

Danny Williams — Thu, 27 May 2010 11:11:47 +0000

Robert Bates - Control for LIVC purposes only can be by direct unpowered mechanical connection to the accelerator pedal (or twist grip). Control for duration increase with rpm increase only can be by a simple centrifugal mechanism. However control to utilise both LIVC and duration-with-rpm simultaneously could be a bit trickier. Although a mechanical solution is possible, control through a ECU/hydraulic/electric etc. system would probably be more effective.
Robert Jamieson - The likely market would appear to be the OEMs. Even though the helical cam essentially replaces a normal camshaft it is not really a “drop-in” replacement usually. I would think that it would be suitable for both developing and developed nations - but I see your point.
There is an earlier, simpler, non-LIVC version of the cam that may be more suitable for aftermarket use and simpler designs. The earlier version has actually had more testing (road and dyno) than the later type of camshaft.

By: Robert Jamieson

Robert Jamieson — Sat, 22 May 2010 06:40:44 +0000

Bearing in mind that this development is fairly “low tech” in its approach (i.e. does not rely on state of the art computerised, camshaft-less valve actuating systems that the major automotive manufacturers are apparently developing for their next generation models), what would be the likely market(s) for this camshaft ?
Would it be possibly a way for developing nation manufacturers to obtain more performance (both output, and fuel economy) from their necessarily simpler designs of motors ?
Or maybe, seen as an after-market sales opportunity for camshaft developers in, say, the United States ?

By: Danny Williams

Danny Williams — Sat, 22 May 2010 05:42:45 +0000

Frank - it actually does work as neatly described by John Coxon. You can see the cam running in videos on the “helical camshaft” website.
I also find the “motions” hard to picture and especially difficult to describe in words.

By: frank

frank — Fri, 21 May 2010 17:52:41 +0000

Very good, if it works, and I hope it does. I would like to see more so I can understand the motions

By: Robert Bates

Robert Bates — Fri, 21 May 2010 05:40:52 +0000

This is a very slick solution to an age-old problem! I’m sure that CNC-controlled equipment could manage the fabrication and tolerances without too much fuss… Simple, elegant and mostly self-contained. Any idea what kind of control mechanism(s) will work with it?

By: Robert Bennett

Robert Bennett — Mon, 17 May 2010 23:41:12 +0000

Amazing!