206 replies to this topic

[gruntguru]

Thanks to Steve Canyon for the interesting link below. This is a nice idea - probably about 20 years too late as I see electro or electro-hydraulic systems as front runners for the passenger car market. The Williams system however (IMO) currently has a clear advantage for
racing applications, courtesy of its higher speed capabilities - actuation speed and valve acceleration potential is as high as current mechanical camshaft technology.

To me it seems its only limitation is that lift is limited to the value obtained at the system's "mildest" camshaft setting, "wilder" profiles being obtained by adding dwell at full lift. Even this does not seem to be an issue if the following quote (from the website) is accurate.

"dynamometer testing of road engines has shown that even with the WHC limited to only about 30 degrees increase in duration, a typical road engine can increase its power by 25% to 30% at the same RPM power peak as the standard cam – and the idle and low RPM behaviour are totally normal"

The website is quite good (no hype, plenty of info), the videos are refreshingly "backyard" if a bit drawn out. I look forward to comments from the forum.

http://www.helicalcamshaft.com/

Edited by gruntguru, 03 June 2010 - 21:45.

[jrobson]

It's easy to see if it is usable or not... email them and ask for a price to build one

[gruntguru]

It's easy to see if it is usable or not... email them and ask for a price to build one

I saw somewhere on their site it costs them approx $1500 (AUS) to have a cam made as a one-off. (The helical part would be the problem - the lobes are just a normal cam grinding operation) Adding an actuation system would be similar to current VVT technology.

Sounds pretty cheap to me! Production tooloing would reduce that by an order of magnitude easily.

Edited by gruntguru, 05 June 2010 - 03:07.

[Chris Wilson]

One potential issue springs immediately to mind in a race engine environment. The space problem with packing the lobe mechanism and drive for its movement means that, as they admit, the use of a forked finger follower operating two valves of a 4 valve per cylinder head is required. This would double the loadings on the finger, and they are already a very stressed part when dealing with the sort of valve spring forces needed to control high RPM valve movement. Whether gas springs would reduce the loadings enough I do not know as I don't move in such advanced circles For a less stressed road car engine it certainly appears an interesting concept.

[cheapracer]

One potential issue springs immediately to mind in a race engine environment. The space problem with packing the lobe mechanism and drive for its movement means that, as they admit, the use of a forked finger follower operating two valves of a 4 valve per cylinder head is required. This would double the loadings on the finger, and they are already a very stressed part when dealing with the sort of valve spring forces needed to control high RPM valve movement.

Honda have been using forked finger, single lobe cam 4 valve heads in high rpm production engines at least since the 1972 XL250 which easily turned 9000rpm.

[Kelpiecross]

I just noticed this topic from a few months ago. I have actually seen this gadget running and being tested. As someone who has spent a lot of time working (unsuccessfully) on ideas to vary the valve opening duration - I have to say that I was absolutely astounded to see this cam performing. If there are any fundamental problems in the system, they were not obvious to me. Even the seemingly-ridiculous almost halving of the fuel use at idle is a genuine result - at least with this engine.
Generally speaking there is no (and never has been any) mechanical continuously variable duration systems - the only possible rivals are "camless" types. And suddenly I see this thing calmly running away to itself like one you would buy in a shop (so to speak).
I know that the people behind the cam have had very little response or interest from the motor industry. Why this is totally puzzles me. I am not silly enough to suggest a conspiracy to suppress the idea but I do wonder if companies and engineers in general are a bit frightened of it and just hope it will go away. the cam makes things like the VTEC, Valvetronic, cam phasing etc. and all the camless ideas look a bit pointless. There must be billiions of dollars invested in all the research etc. into the many variable timing systems - all of which basically is made obsolete by this cam. And what it would do the car racing world defies description. People really should not ignore this cam - I don't think it is going to go away.
I should point out that I have no connection with the makers of the cam.
As well as the company's website there is a Wiki article:
http://en.wikipedia....elical_camshaft
This has much the same stuff but the photos and the graphs at the end are interesting. The "discussion" page is also interesting.

[Bloggsworth]

I seem to recall that the Alfa-Romeo variable camshaft used a helical thread powered by engine oil pressure - I assume it fell out of use because if the oil got sludgy it stopped working properly.

[MatsNorway]

I seem to recall that the Alfa-Romeo variable camshaft used a helical thread powered by engine oil pressure - I assume it fell out of use because if the oil got sludgy it stopped working properly.

They did have a oil pressure actuated rotational device to adjust the cam. I always assumed it was something like this:



I did a similar drawing based upon the description when i was 19yrs. without knowing about it already existed ofc. oh well.. only 40 years behind.

Toyota did btw copy alfa romeo relentless back in the day. I know a guy that has a toyota engine in hes Vintage formula car, it was supposedly very very much equal the alfa. Not sure if the crank fitted directly inn. It was a 1.8L stroked up to 2L

Cool car btw has side venturies and all.

I wonder how this one looks lnside:

Edited by MatsNorway, 18 October 2010 - 19:19.

[Greg Locock]

Why this is totally puzzles me.

Um, because the 2 position systems provide 99% of the benefit for zero licensing cost?

[gruntguru]

Um, because the 2 position systems provide 99% of the benefit for zero licensing cost?

I would put it closer to 50%. The Williams system offers a far wider range of valve duration, continuous variability and "Late Inlet Valve Closing" which can almost eliminate intake pumping loss. I would like to see infinitely adjustable LIVC combined with DI - completely throttleless operation?

Edited by gruntguru, 18 October 2010 - 22:48.

[cheapracer]

Couple of invention PDF's quoted in the Wiki discussion page...

http://www.freepaten...om/1527456.html

http://www.freepaten...om/7341032.html

Edited by cheapracer, 19 October 2010 - 03:30.

[Bloggsworth]

They did have a oil pressure actuated rotational device to adjust the cam. I always assumed it was something like this:

The Alfa system plunged a coarse ACME thread in and out of the end of the camshaft - Push the thread in and the camshaft rotates widdershins (If you aren't from oop north, you'd better google it)


Somewhere I have drawings of my 3 ideas in ROBOCAD on 5.25" floppies - I no longer have any computers which read them!

Edited by Bloggsworth, 19 October 2010 - 18:03.

[Bloggsworth]

Found the drawing of the belt/chain method:



I'll find the differential type soon - I've upgraded/changed several computers over the last couple of years, I've lost track of where I filed it...

Edited by Bloggsworth, 19 October 2010 - 22:00.

[Kelpiecross]

I think you have to separate the different forms of variable timing. The Alfa system is the fairly common cam phasing type where a normal cam is rotated to vary the timing. Cam phasing really has little effect on performance. In a similar way systems that vary the lift (like Valvetronic etc.) also don't do much.
The only thing that really has a big effect on performance is varying the valve opening duration - like VTEC-type arrangements and the helical cam.

On the subject of whether the VTEC does the same job as the helical cam - cars have got by forever with totally normal cams that didn't vary anything - I've never owned a car with any form of variable timing. So you don't really need it. But if you do want continuously variable duration - the helical cam is the way to do it - it makes all the other systems look very limited and primitive.

[Bloggsworth]

I found the drawing of the differential type. The worm drive adjusts the phase difference between cam & crankshaft (Which counter-rotates).

Edited by Bloggsworth, 20 October 2010 - 08:10.

[Kelpiecross]

Nice drawing and a clever mechanism - but it is still ordinary cam phasing.

[motto]

I just noticed this topic from a few months ago. I have actually seen this gadget running and being tested. As someone who has spent a lot of time working (unsuccessfully) on ideas to vary the valve opening duration - I have to say that I was absolutely astounded to see this cam performing. If there are any fundamental problems in the system, they were not obvious to me. Even the seemingly-ridiculous almost halving of the fuel use at idle is a genuine result - at least with this engine.
Generally speaking there is no (and never has been any) mechanical continuously variable duration systems - the only possible rivals are "camless" types. And suddenly I see this thing calmly running away to itself like one you would buy in a shop (so to speak).
I know that the people behind the cam have had very little response or interest from the motor industry. Why this is totally puzzles me. I am not silly enough to suggest a conspiracy to suppress the idea but I do wonder if companies and engineers in general are a bit frightened of it and just hope it will go away. the cam makes things like the VTEC, Valvetronic, cam phasing etc. and all the camless ideas look a bit pointless. There must be billiions of dollars invested in all the research etc. into the many variable timing systems - all of which basically is made obsolete by this cam. And what it would do the car racing world defies description. People really should not ignore this cam - I don't think it is going to go away.
I should point out that I have no connection with the makers of the cam.
As well as the company's website there is a Wiki article:
http://en.wikipedia....elical_camshaft
This has much the same stuff but the photos and the graphs at the end are interesting. The "discussion" page is also interesting.

I have seen the helical cam being demonstrated in person as well. One of the main things that impressed me (apart from the fact that it ran like a standard cam) was that it just was a direct swap for the standard cam. If you have ever looked at a Valvetronic (especially) or a VTEC - they are a mechanic's worst nightmare. The helical cam is just a cam - everything else is standard. Another impressive thing was that only 25mm axial movement of the shaft will change the duration by 85 degrees (!). On +85 degrees the engine turned over on the starter as if the sparkplugs weren't fitted - zero on the compression gauge.
I also had a ride in the variable-cammed EA Falcon. I think this is the 30 degree/30% improved power engine mentioned previiously. It also seemed to run like a standard EA - except for the exhaust note possibly starting to howl a bit over 3500RPM when the cam started to come in.
I can't understand why we haven't seen more of this helical cam idea either. It would be devastating in MotoGP.

[gruntguru]

I also had a ride in the variable-cammed EA Falcon. I think this is the 30 degree/30% improved power engine mentioned previiously.

Couldn't find the EA Falcon reference. Does this have a helical cam? More info?

[cheapracer]

cars have got by forever with totally normal cams that didn't vary anything - I've never owned a car with any form of variable timing. So you don't really need it.

Cars that don't meet Euro 4 you mean.

[Greg Locock]

Couldn't find the EA Falcon reference. Does this have a helical cam? More info?

Not an EA it was AU. it isn't helical, more like a pulley on a sloppy keyway (ie it rotated) and it wasn't 30% it was more like 15%, and that included some other stuff, like a higher red line, from memory.

Edited by Greg Locock, 21 October 2010 - 05:35.

[Kelpiecross]

Not an EA it was AU. it isn't helical, more like a pulley on a sloppy keyway (ie it rotated) and it wasn't 30% it was more like 15%, and that included some other stuff, like a higher red line, from memory.

No - it was an EA. I afraid Mr.Motto has unintentionally led people astray a little. He is not referring to the Ford factory cam-phasing system. I never saw it run but I saw the cam. It wasn't helical but it was a similar idea - I think limited to about 30 degrees duration increase. It had a centrifugal controller on the front inside the chain sprocket. A few years earlier I saw a similar pattern cam and controller running in (I think) a 3-cylinder Charade. It was a +40 degree cam and it really did scream. From memory I think the EA and Charade-type cams were put on the backburner as the helical cam had an unlimited duration range (allowing LIVC) making the earlier cams a bit obsolete.
As I wrote earlier, I was staggered by some of the things I saw. If I had been shown a working antigravity machine I don't think it would have surprised me more.
These people have been very busy.

[Bargebear]

I have seen the helical cam being demonstrated in person as well. One of the main things that impressed me (apart from the fact that it ran like a standard cam) was that it just was a direct swap for the standard cam. If you have ever looked at a Valvetronic (especially) or a VTEC - they are a mechanic's worst nightmare. The helical cam is just a cam - everything else is standard. Another impressive thing was that only 25mm axial movement of the shaft will change the duration by 85 degrees (!). On +85 degrees the engine turned over on the starter as if the sparkplugs weren't fitted - zero on the compression gauge.
I also had a ride in the variable-cammed EA Falcon. I think this is the 30 degree/30% improved power engine mentioned previiously. It also seemed to run like a standard EA - except for the exhaust note possibly starting to howl a bit over 3500RPM when the cam started to come in.
I can't understand why we haven't seen more of this helical cam idea either. It would be devastating in MotoGP.

As an ex amateur not-very-successful motorbike racer I was interested in the comment concerning the possible application of the helical cam in MotoGP. Assuming the cam can produce whatever amount of duration needed and not be be rev-limited - how much difference would it make to a MotoGP engine? If F1 engines were not limited to 18K by regulation, I imagine they would probably be using 22K+. So why are un-rev limited MotoGP bikes down around 17K or thereabouts. Would the engines be too "peaky" and unrideable if they use longer duration/more radical cams? I seem to recall reading a while back that Honda claimed their MotoGP engines could make an extra 100HP but would be too tricky to ride. Presumably the helical cam could fix any rideability problems.
Would the helical cam actually be legal in MotoGP racing? I assume that the engine designers are aware of the helical cam - why are they not using it? I am no expert but the cam doesn't seem to have any fundamental flaw in its basic principle or geometry of operation.

[gruntguru]

As an ex amateur not-very-successful motorbike racer I was interested in the comment concerning the possible application of the helical cam in MotoGP. Assuming the cam can produce whatever amount of duration needed and not be be rev-limited - how much difference would it make to a MotoGP engine? If F1 engines were not limited to 18K by regulation, I imagine they would probably be using 22K+. So why are un-rev limited MotoGP bikes down around 17K or thereabouts. Would the engines be too "peaky" and unrideable if they use longer duration/more radical cams? I seem to recall reading a while back that Honda claimed their MotoGP engines could make an extra 100HP but would be too tricky to ride. Presumably the helical cam could fix any rideability problems.
Would the helical cam actually be legal in MotoGP racing? I assume that the engine designers are aware of the helical cam - why are they not using it? I am no expert but the cam doesn't seem to have any fundamental flaw in its basic principle or geometry of operation.

Not sure of the legalities of VVT and motoGP.

I can only see two drawbacks of the helical cam for outright performance
1. The requirement to use a single finger-follower on each cylinder will restrict valve accelerations compared to a direct acting bucket for each valve.
2. The maximum valve lift is dictated by peak valve acceleration (at redline RPM) and the minimum-duration profile. This will necessarily be somewhat less than the maximum lift for a fixed duration cam. On the positive side, the minimum duration profile for a competition Helical cam would not need to be as mild as for say a production car. Accordingling the range of duration adjustment would probably not need to be as large, resulting in some space saving as well.

Of course the extreme duration available when using the Helical cam will more than offset the small loss of valve lift due to 1 and 2 above.

BTW I think the high cost of manufacture woud be easily overcome if volume was to increase.

[J. Edlund]

I just noticed this topic from a few months ago. I have actually seen this gadget running and being tested. As someone who has spent a lot of time working (unsuccessfully) on ideas to vary the valve opening duration - I have to say that I was absolutely astounded to see this cam performing. If there are any fundamental problems in the system, they were not obvious to me. Even the seemingly-ridiculous almost halving of the fuel use at idle is a genuine result - at least with this engine.
Generally speaking there is no (and never has been any) mechanical continuously variable duration systems - the only possible rivals are "camless" types. And suddenly I see this thing calmly running away to itself like one you would buy in a shop (so to speak).
I know that the people behind the cam have had very little response or interest from the motor industry. Why this is totally puzzles me. I am not silly enough to suggest a conspiracy to suppress the idea but I do wonder if companies and engineers in general are a bit frightened of it and just hope it will go away. the cam makes things like the VTEC, Valvetronic, cam phasing etc. and all the camless ideas look a bit pointless. There must be billiions of dollars invested in all the research etc. into the many variable timing systems - all of which basically is made obsolete by this cam. And what it would do the car racing world defies description. People really should not ignore this cam - I don't think it is going to go away.
I should point out that I have no connection with the makers of the cam.
As well as the company's website there is a Wiki article:
http://en.wikipedia....elical_camshaft
This has much the same stuff but the photos and the graphs at the end are interesting. The "discussion" page is also interesting.

The helical camshaft can only increase and decrease the duration, so it wouldn't replace cam phasing, rather, it would need to use cam phasing in order to adjust both timing and duration. But systems like BMW's Valvetronic can already adjust duration, valve lift and timing for what I suspect a much lower cost. The stated cost of $1500 is far too much, for that sum you could get a camless system which offer some significant advantages over a mechanical system like this.

[Kelpiecross]

The helical camshaft can only increase and decrease the duration, so it wouldn't replace cam phasing, rather, it would need to use cam phasing in order to adjust both timing and duration. But systems like BMW's Valvetronic can already adjust duration, valve lift and timing for what I suspect a much lower cost. The stated cost of $1500 is far too much, for that sum you could get a camless system which offer some significant advantages over a mechanical system like this.

The helical cam for high RPM power increase doesn't necessarily need cam phasing. For combined LIVC and power increase at high RPM it does need phasing.

The Valvetronic is a bit of a disaster. If you want to point out a very good existing system - the VTEC is far superior to Valvetronic - but the VTEC is not continuous.

The Valvetronic really is just a variable lift system. It can adjust duration but this is done in such a way that makes it fairly ineffective. In their own writings on the Valvetronic BMW don't really refer to it as a variable duration system - but as a variable lift system.

It also needs cam phasing - BMW call their system Vanos.

The Valvetronic is also quite rev-limited - I don't think there are any "M" BMWs that use it. If it was an effective system they would use it.

$1500 was reportedly the cost of the prototype - production helical cams would be a lot cheaper (- but not that cheap). Probably a lot cheaper than the Valvetronic.

You may know differently but I don't think you can get a "camless" system at any price at present - certainly not one that is not very rev-limited. I read in John Lumley's book that the Lotus system was about $1000 per valve.

[gruntguru]

You may know differently but I don't think you can get a "camless" system at any price at present - certainly not one that is not very rev-limited.

Bishop rotary valve works fine.

[Kelpiecross]

Bishop rotary valve works fine.

By "camless" I mean poppet valves not actuated by a camshaft.

The Bishop rotary valve "works fine"? I would have expressed this slightly differently - "the Bishop rotary valve is an abomination".
I don't think the various features of the BRV are even worthy of discussion - all those gears for a start. I don't know how a place like Bishop's ever got involved with rubbish like this.

[gruntguru]

By "camless" I mean poppet valves not actuated by a camshaft.

Sorry. I would never have guessed.

The Bishop rotary valve "works fine"? I would have expressed this slightly differently - "the Bishop rotary valve is an abomination".

Despite a very brief gestation, the BRV had performance comparable to the best poppet valve engines in the world at one time, so I still say it works (or worked) fine.

I don't think the various features of the BRV are even worthy of discussion - all those gears for a start.

You're new here aren't you? We even discuss the relative merits of Power and Torque. BTW weren't "all those gears" one of the "various features of the BRV" or were you not intending to discuss them?

[Kelpiecross]

Sorry. I would never have guessed.


Despite a very brief gestation, the BRV had performance comparable to the best poppet valve engines in the world at one time, so I still say it works (or worked) fine.


You're new here aren't you? We even discuss the relative merits of Power and Torque. BTW weren't "all those gears" one of the "various features of the BRV" or were you not intending to discuss them?

Sorry - didn't mean to discuss any feature. Another one - how did they intend to join (without leaks) a spinning, red-hot exhaust onto the stationary part of the exhaust system?
The BRV may have had a performance comparable etc. etc. - but at what expense of complication? And certainly little chance of variable duration etc. with the BRV.

[cheapracer]

Would the helical cam actually be legal in MotoGP racing? I assume that the engine designers are aware of the helical cam - why are they not using it?

Because it's one more complication and race tracks don't need it not to mention riders are quite capable of riding in the current powerbands.

[gruntguru]

Another one - how did they intend to join (without leaks) a spinning, red-hot exhaust onto the stationary part of the exhaust system?
The BRV may have had a performance comparable etc. etc. - but at what expense of complication? And certainly little chance of variable duration etc. with the BRV.

You wil find details of the seals etc HERE. This is one area where Bishop made major advances with a fairly old (rotary valve) concept. As for complexity, the BRV Ilmor engine had far fewer moving parts than the poppet valve version of the same engine.

[Kelpiecross]

You wil find details of the seals etc HERE. This is one area where Bishop made major advances with a fairly old (rotary valve) concept. As for complexity, the BRV Ilmor engine had far fewer moving parts than the poppet valve version of the same engine.

I have noticed that most of your (gruntguru's) comments on various topics on this forum are eminently sane and logical. It puzzles me then that you are a champion of the BRV. Do you work for Bishops or maybe you even worked on the BRV?
Arguments such as "less moving parts" are not entirely valid in this context. The typical poppet valve system may have millions of parts but it is well-known that generally they all stay together and perform their tasks for the entire life of the car sometimes with no attention whatsoever. So it doesn't really matter about how many parts there are.
I had seen the "HERE" material before.
I am no supporter of rotary valves of any kind - but systems like the Coates rotary valve appear to a hundred times more sensible than the BRV. (But I still think poppet valves are better).
The BRV system seems to me to be analogous to a poppet valve arrangement where a shaft running the length of the engine has a right angle gear drive and a short camshaft branching off across the engine to serve each cylinder. It would work but it would be pointless and silly. Which could also be said about the BRV.

Edited by Kelpiecross, 30 October 2010 - 06:14.

[gruntguru]

I have noticed that most of your (gruntguru's) comments on various topics on this forum are eminently sane and logical. It puzzles me then that you are a champion of the BRV. Do you work for Bishops or maybe you even worked on the BRV?

Thank you. No.

Arguments such as "less moving parts" are not entirely valid in this context. The typical poppet valve system may have millions of parts but it is well-known that generally they all stay together and perform their tasks for the entire life of the car sometimes with no attention whatsoever. So it doesn't really matter about how many parts there are.
I had seen the "HERE" material before.

One cylindrical valve and one (very lightly, constantly loaded) gear per cylinder - both rotating at constant 1/2 engine speed. Can't see where the reliability issues might be. Poppet valve trains on the other hand have demanded enormous development to get them to where they are today and still remain one of the key areas of compromise. For example, any front-running race car will have a valve train that represents a compromise of engine performance versus durability. (The only exceptions are some artificially limited series - particularly rpm limits.)

IMO the BRV with further development would have better reliability than poppet valves in a road car yet offer race-car breathing.

I am no supporter of rotary valves of any kind - but systems like the Coates rotary valve appear to a hundred times more sensible than the BRV. (But I still think poppet valves are better).

I'm sure poppet valves are better, however if poppet valve development had begun at the same time as Bishop started on the BRV, poppet valves wouldn't even exist today.

The BRV system seems to me to be analogous to a poppet valve arrangement where a shaft running the length of the engine has a right angle gear drive and a short camshaft branching off across the engine to serve each cylinder. It would work but it would be pointless and silly. Which could also be said about the BRV.

Well its fairly obvious why they had to drive it that way, but mechanically the gear-train would be very lightly loaded and not at all intermittent like a poppet system. As to "pointless" the BRV has a few clear advantages over a poppet system:
- better breathing
- cooler chamber (reduced knock - higher CR)
- superior tumble (reduced knock - higher CR)
- integral head/sleeve (no head gasket)
- no rpm limit
- lower weight (the Ilmor/BRV V10 was 16kg lighter!)
- significantly reduced engine height
- lower CG

I still don't see the disadvantages. Over to you Magoo.

EDIT. They could have run a shaft full length along each bank with a bevel drive at each rotary valve. That would still be simpler than two camshafts along each bank, each having two lobes, two pneumatic springs etc per cylinder. The chosen system of gears is actually simple and elegant.

Edited by gruntguru, 30 October 2010 - 07:53.

[cheapracer]

Do you work for Bishops...?

He's fielded that accusation before today

[gruntguru]

Do you work for Bishops?

He's fielded that accusation before today

I wish I did - it would have been an exciting project.

I actually had a meeting with them way back when they were shopping for a dynamometer. They gave me very little idea what sort of research it was.

[SteveCanyon]

The BRV engine has been tested and even in the early stages it was getting close to the same power output as the then current F1 engines. So the power factor isn't a consideration.
The sealing may well have been, but decades of rotary engine experience would have to count for a hell of a lot there; there's relative few problems with them now.
The reliability again should be better than any poppet valve system as there's simply nothing reciprocating, only rotating. So nothing banging open & closed. Varying the timing wouldn't be hard, use the helical system like the Toyota (and others) VVT-i gear.

Anyway, all that being said ...... yes I never cease to be amazed how well the old poppet-valve piston engines can be made to go, but the more I see of them and the Heath Robinson contraptions used to make them perform better, the more I like electric motors.

[Magoo]

The Bishop rotary valve and the Williams helical camshaft have the same future in production automobiles: None. They are clever and interesting but offer no material advantage over existing technologies.

[Kelpiecross]

The BRV engine has been tested and even in the early stages it was getting close to the same power output as the then current F1 engines. So the power factor isn't a consideration.
The sealing may well have been, but decades of rotary engine experience would have to count for a hell of a lot there; there's relative few problems with them now.
The reliability again should be better than any poppet valve system as there's simply nothing reciprocating, only rotating. So nothing banging open & closed. Varying the timing wouldn't be hard, use the helical system like the Toyota (and others) VVT-i gear.

Anyway, all that being said ...... yes I never cease to be amazed how well the old poppet-valve piston engines can be made to go, but the more I see of them and the Heath Robinson contraptions used to make them perform better, the more I like electric motors.

Any timing variation on the BRV would have to be the equivalent of the not-very-effective cam phasing (in fact Bishop's have a patent on this point). It is hard to imagine the BRV having a variable duration system like VTEC or the helical cam.
I think people have mentioned before that the rotary engine solved its sealing problems. But the BRV sealing problems are several magnitudes greater. At times the spinning exhaust would be verging on white hot - at other times relatively cool. In comparison the rotary engine seals are much cooler. The spinning rotary valve tube itself would be cool at the intake end and redhot a few inches away at the exhaust end. If Bishop's can solve the sealing problems of the BRV - maybe they should demonstrate it. It would have to survive for the life of the engine (or car) as the equivalent area of a poppet valve engine does.
All the other well-known rotary valve systems such as Cross, Norton and Aspin would seem to have much more potential to become useable rotary valve systems than the BRV.

How is it that we have never seen articles or engineering papers on this BRV F1 engine? It would be of great interest to many people and great publicity for Bishop's.
The truth is that it probably never existed.

[Kelpiecross]

The Bishop rotary valve and the Williams helical camshaft have the same future in production automobiles: None. They are clever and interesting but offer no material advantage over existing technologies.

Sadly Mr. Magoo you could be right. But I think there is a difference between the BRV and the WHC (and other cam variation systems). The automotive world has pretty much settled on the poppet valve - even a "perfect" rotary valve would have little or no advantage - especially in a production car. There is a lot of money still being spent on ways to vary all aspects of the poppet valve's timing. Including camless types this probably runs into billions of dollars. As I see it the WHC does have many advantages over all existing timing variation systems.
The BRV would appear to have almost no potential for all the poppet valve's "tricks". It could do the equivalent of cam phasing - but variable duration, variable lift etc. would appear to be pretty much impossible. So LIVC, EIVC, LIVO and all of the possible combinations of of these letters can be done with poppet valves - not with the BRV. Can you imagine the equivalent of Valvetronic's idling with half a millimetre of lift with the BRV?

Edited by Kelpiecross, 30 October 2010 - 12:48.

[SteveCanyon]

Any timing variation on the BRV would have to be the equivalent of the not-very-effective cam phasing (in fact Bishop's have a patent on this point). It is hard to imagine the BRV having a variable duration system like VTEC or the helical cam.

Rather easy in fact, though yes it would not alter the effective lobe separation angles and that's not as good.

I think people have mentioned before that the rotary engine solved its sealing problems. But the BRV sealing problems are several magnitudes greater. At times the spinning exhaust would be verging on white hot - at other times relatively cool. In comparison the rotary engine seals are much cooler.

Not from anything I've ever heard about rotaries - the exhaust typically runs hotter than any petrol engine. I've never seen or heard anything to the contrary.

The spinning rotary valve tube itself would be cool at the intake end and redhot a few inches away at the exhaust end. If Bishop's can solve the sealing problems of the BRV - maybe they should demonstrate it.

They did demonstrate it in both single-cylinder and multi-cylinder prototypes.

It would have to survive for the life of the engine (or car) as the equivalent area of a poppet valve engine does.
All the other well-known rotary valve systems such as Cross, Norton and Aspin would seem to have much more potential to become useable rotary valve systems than the BRV.

So where are they? I'd be happy to see any of them in production.

How is it that we have never seen articles or engineering papers on this BRV F1 engine? It would be of great interest to many people and great publicity for Bishop's.
The truth is that it probably never existed.

You mean apart from the link given a few posts above? And the multiple threads on it here and other forums?
Anyway, fortunately I don't have to guess or make up stories as I actually know one of the guys that worked on them, and they worked exactly as advertised.

[J. Edlund]

The helical cam for high RPM power increase doesn't necessarily need cam phasing. For combined LIVC and power increase at high RPM it does need phasing.

The Valvetronic is a bit of a disaster. If you want to point out a very good existing system - the VTEC is far superior to Valvetronic - but the VTEC is not continuous.

The Valvetronic really is just a variable lift system. It can adjust duration but this is done in such a way that makes it fairly ineffective. In their own writings on the Valvetronic BMW don't really refer to it as a variable duration system - but as a variable lift system.

It also needs cam phasing - BMW call their system Vanos.

The Valvetronic is also quite rev-limited - I don't think there are any "M" BMWs that use it. If it was an effective system they would use it.

$1500 was reportedly the cost of the prototype - production helical cams would be a lot cheaper (- but not that cheap). Probably a lot cheaper than the Valvetronic.

You may know differently but I don't think you can get a "camless" system at any price at present - certainly not one that is not very rev-limited. I read in John Lumley's book that the Lotus system was about $1000 per valve.

From how you describe Valvetronic I can only assume you don't know how it operate.

Valvetronic adjust both duration and valvelift, and since it is combined with electro-hydraulic phasing it also adjust timing. VTEC can only switch between two cam profiles which make it quite primitive. The disadvantage with Valvetronic is that it requires more space in the cylinder head which have made it difficult to combine with direct injection, although I think that have been solved in the later engines. It is also unsuitable for high engine speeds, which is why it isn't found in the M engines.

Valvetronic use early intake valve closure at part load, operating according to the Atkinson-Miller cycle. The less torque needed, the earlier the intake valve is closed and the less lift is used. Lift and duration can however not be controlled independently of each other, less duration is always equal to less lift. From that point I can see the advantages with Fiats Multiair compared to the Valvetronic.

The lift curves for Valvetronic can be found in this power point presensation:
http://www.md.kth.se...t07/BMW6Fig.PPT

Lotus camless system is very expensive, but it not really intended for anything else than research and development. The Lotus system is hydraulic and uses expensive aerospace type electro-hydraulic valves from MOOG.

A pneumatic camless system, using pneumatic cylinders, small electric solenoids, laser based valve lift measurement, hydraulic damping and a compressor have been cost estimated at around $300 more than a conventional cam system for series production (for a four cylinder I think). Good for at least 8000 rpm, and compared to cams it only cost a few kW more to operate at peak power. Average power consumption is generally lower than with cams due to lower lifts at part load. Compared to cams it is also lighter and more compact. There are a few manufacturers looking at it, but so far supercar manufacturer Koneigsegg are the only ones who have said they want to introduce it.

Fiats Multiair is probably a good step toward an electro-hydraulic camless system. Today it uses a single cam to operate the exhaust valves and the hydraulic pistons which control the intake valve hydralic pistons via a solenoid valve, much like pump injectors for diesel engines operate.

[Kelpiecross]

From how you describe Valvetronic I can only assume you don't know how it operate.

Valvetronic adjust both duration and valvelift, and since it is combined with electro-hydraulic phasing it also adjust timing. VTEC can only switch between two cam profiles which make it quite primitive. The disadvantage with Valvetronic is that it requires more space in the cylinder head which have made it difficult to combine with direct injection, although I think that have been solved in the later engines. It is also unsuitable for high engine speeds, which is why it isn't found in the M engines.

Valvetronic use early intake valve closure at part load, operating according to the Atkinson-Miller cycle. The less torque needed, the earlier the intake valve is closed and the less lift is used. Lift and duration can however not be controlled independently of each other, less duration is always equal to less lift. From that point I can see the advantages with Fiats Multiair compared to the Valvetronic.

The lift curves for Valvetronic can be found in this power point presensation:
http://www.md.kth.se...t07/BMW6Fig.PPT

Lotus camless system is very expensive, but it not really intended for anything else than research and development. The Lotus system is hydraulic and uses expensive aerospace type electro-hydraulic valves from MOOG.

A pneumatic camless system, using pneumatic cylinders, small electric solenoids, laser based valve lift measurement, hydraulic damping and a compressor have been cost estimated at around $300 more than a conventional cam system for series production (for a four cylinder I think). Good for at least 8000 rpm, and compared to cams it only cost a few kW more to operate at peak power. Average power consumption is generally lower than with cams due to lower lifts at part load. Compared to cams it is also lighter and more compact. There are a few manufacturers looking at it, but so far supercar manufacturer Koneigsegg are the only ones who have said they want to introduce it.

Fiats Multiair is probably a good step toward an electro-hydraulic camless system. Today it uses a single cam to operate the exhaust valves and the hydraulic pistons which control the intake valve hydralic pistons via a solenoid valve, much like pump injectors for diesel engines operate.

I do actually know how the Valvetronic works. It is the latest in a long line (going back to the steam age) of variable valve arrangements that fall into the general class of "oscillating cam" mechanisms. Its main failing (and the failing of all oscillating cam mechanisms) is the link between lift and duration. The Valvetronic has a very wide duration range - unfortunately this range is more-or-less from zero to about normal duration. A duration range in this position is not very useful. The Valvetronic's trick of controlling load is really just a novelty - once again not very useful. The VTEC, although not continuous, is highly effective. It can basically double the power of an engine - the Valvetronic doesn't really do anything. The Valvetronic's main purpose (and this is not entirely a joke) is so that when Honda owners say "My engine has VTEC" the BMW owner can reply "Well, my engine has Valvetronic - so there".

I think everbody in this discussion has made their positions clear and are not going to change. It is a bit like fanatical support of a football team or a political party - no real logic in it, just human behaviour. I have even heard of people (but never met one) who vote for the Labor party or the Greens.

Valvetronic, VTEC, Multiair, BRV etc. etc. are all as somebody wrote, "Heath Robinson". I am an unashamed voter for the helical cam, I would say that it has several orders of magnitude less of the influence of Mr. Robinson. It essentially replaces a "normal" cam without any other paraphenalia and it does far more than all of Mr. Robinson's other cam system creations.

The SAE (especially) seem to publish automotive papers on things that even appear to be distinctly dodgey. But no paper on the BRV F1 engine? There are people who swear on the bible that they have been abducted by aliens - but would you believe them?
The BRV F1 engine made the same (or more) power than an equivalent conventional F1 engine? With very little development and a radical system of breathing? I would be more inclined to believe the "little grey men" stories - they are more believable.

Edited by Kelpiecross, 31 October 2010 - 04:24.

[gruntguru]

Any timing variation on the BRV would have to be the equivalent of the not-very-effective cam phasing (in fact Bishop's have a patent on this point). It is hard to imagine the BRV having a variable duration system like VTEC or the helical cam.

Yes, in the basic layout developed by Bishop, the BRV does not have variable duration - like 99.9% of the poppet-valve engines on planet earth. So it only offers the advantages listed in my previous post, and you have hit on one thing it doesn't do.

BTW, variable duration and timing looks like a very straightforward development to me - much simpler than the helical cam or any of the other technologies out there.

But the BRV sealing problems are several magnitudes greater. At times the spinning exhaust would be verging on white hot - at other times relatively cool. The spinning rotary valve tube itself would be cool at the intake end and redhot a few inches away at the exhaust end.

Perhaps you should read the Auto Tech article again more thoroughly as it adresses these very issues. 1. The sealing technology used is quite robust and used widely in turbines etc. 2. The temperature gradient along the valve is very high - much like the ends of a turbocharger shaft although not as great. The gradient across the valve is also high and causes distortion of the valve, cleverly overcome by the arrangement of clearance, seals and bearings.

Development of the BRV to the reliability claimed, at the very high specific outputs of F1, would easily convert to long life in a road vehicle application.

All the other well-known rotary valve systems such as Cross, Norton and Aspin would seem to have much more potential to become useable rotary valve systems than the BRV.

??? The BRV is essentially a Cross/Norton system with the bugs sorted out.

[cheapracer]

But no paper on the BRV F1 engine?


The BRV F1 engine made the same (or more) power than an equivalent conventional F1 engine? With very little development and a radical system of breathing? I would be more inclined to believe the "little grey men" stories - they are more believable.

So theres no SAE paper and that then makes it bogus? Felix, you got a SAE paper on your running engines?

If I read the articles properly the vales were developed for real and with CFD over many years - how long should it take to develop the flow dynamics of what is basically an unobstructed hole?

Why exactly do you have such a hard on for these guys anyway?

[Kelpiecross]

So theres no SAE paper and that then makes it bogus? Felix, you got a SAE paper on your running engines?

If I read the articles properly the vales were developed for real and with CFD over many years - how long should it take to develop the flow dynamics of what is basically an unobstructed hole?

Why exactly do you have such a hard on for these guys anyway?

What mainly annoys me is that I think people are influenced by the names Bishop, Ilmor, Mercedes, F1 etc. and are not judging this systems on its merits (or lack thereof) - is nobody else game enough to say they think the BRV is hopeless?

[cheapracer]

What mainly annoys me is that I think people are influenced by the names Bishop, Ilmor, Mercedes, F1 etc. and are not judging this systems on its merits (or lack thereof) - is nobody else game enough to say they think the BRV is hopeless?

Not strictly always true but often some of the sub contractor developments are never reported until the product looks viable and is safe to mention.

For Ilmor and Benz to let it be known they were going down this path indicates to me that some solid foundation was made.

FWIW look for Erwin G Baker's rotary valves in the late 30's and 40's.

Edited by cheapracer, 31 October 2010 - 11:02.

[gruntguru]

What mainly annoys me is that I think people are influenced by the names Bishop, Ilmor, Mercedes, F1 etc. and are not judging this systems on its merits (or lack thereof) - is nobody else game enough to say they think the BRV is hopeless?

I don't hesitate to label something is hopeless - all I need is a reason. To my eye, the BRV looks good and no-one has come up with any negatives that make sense.

I found a PHD THESIS on modelling of the BRV engine. Basically supports the claims in the mag article.

They sure made the right call in choosing F1 to kick it off. Obtaining the performance they did in such a short time while bypassing all the exhaust emissions R&D validated that decision. When you read the paper it is obvious that the development team have only scratched the surface of this technology, the untapped potential remaining is unbelievable.

EDIT. Skip to chapters 8 & 9 if you don't have hours to spare.

Another PAPER co-authored by Tony Wallis and the highly regarded Prof Harry Watson.

Edited by gruntguru, 31 October 2010 - 11:52.

[Magoo]

For Ilmor and Benz to let it be known they were going down this path indicates to me that some solid foundation was made.

But on the other hand, isn't it interesting that both Ilmor and Bishop seem to have expunged the engine from their respective institutional memories. Not a word in their marketing and promotional materials. This is odd, as even if the engine were ultimately unsuccessful, it would still serve as an example of both companies' R&D capabilities, it seems to me. Unless it was not a very good example of same.

To me, you guys put an awful lot of credence in an engine you have never seen. Not even a photo of the F1 engine exists, only of the single-cylinder test mules. Meanwhile, claims for this engine have been stretched well beyond those Bishop ever made for it. The engine is an article of faith, like the serpent in the depths of Loch Ness. The most crucial component of enthusiasm for this engine is a desire to believe in it, not in any particular evidence either way. There is no technical evidence.

[gruntguru]

But on the other hand, isn't it interesting that both Ilmor and Bishop seem to have expunged the engine from their respective institutional memories. Not a word in their marketing and promotional materials. This is odd, as even if the engine were ultimately unsuccessful, it would still serve as an example of both companies' R&D capabilities, it seems to me. Unless it was not a very good example of same.

To me, you guys put an awful lot of credence in an engine you have never seen. Not even a photo of the F1 engine exists, only of the single-cylinder test mules. Meanwhile, claims for this engine have been stretched well beyond those Bishop ever made for it. The engine is an article of faith, like the serpent in the depths of Loch Ness. The most crucial component of enthusiasm for this engine is a desire to believe in it, not in any particular evidence either way. There is no technical evidence.

No argument that the BRV will probably never get off the ground. Of course that doesn't stop myself and others from believing in its technical merit. It doesn't even make any sort of case against the technical merit. History is littered with superiour technologies that failed to get up against inferior opposition.

- Someone (Renault I heard) was sufficiently worried to push for a rule change specifically to kill off the Ilmor BRV.
- The reason Bishop are keeping quiet has nothing to do with technical shortcomings.

[cheapracer]

But on the other hand, isn't it interesting that both Ilmor and Bishop seem to have expunged the engine from their respective institutional memories.

To me, you guys put an awful lot of credence in an engine you have never seen.

Well it did come to an abrubt dead end, why continue with something that opposes what you sell retail when you don't have the chance to prove "your superior technical knowhow" even on a race track? I don't see Chev going on much about rotaries or air cooled flat sixes these days.

Ahh I'm just going on the article and the fact that Ilmor did not pursue this engine in MotoGP prefering air sprung poppet valves is damning.