Stock TRX850 head data *caution LOTS of pics*

[davamb]

...When you look at motogp 800cc engines, producing around 220hp (claimed), that's 275hp per litre. Yes formula 1 have around 330hp per litre, but they have a different rule set to enable this...

Hi Quan, I'm an engineer, so I follow F1 mainly for technical reasons (Moto GP for the racing). I've some small understanding of IC engines, can you elaborate on the different rule sets used if it's not dragging this topic too far off course? I'd have thought the specific output of the bikes would be higher, so it's a bit of a surprise to learn the opposite. Is it just driven by fuel consumption limits?

[Quan-Time]

motogp are the fastest accelerating motorsport you can get.. I saw a clip of pedrosa matched against a F1 car, coming out of a corner onto a straight.. WOW.. they both can boogie, but the bike just piped the win.. Looks deceiving on the video tho.

When it comes down to it, the 21litre fuel restriction is the biggest factor for power. Many teams are experimenting with ways to try and save it. Traction control is a big area.. Instead of retarding, or missing a spark event, they are ignoring a FUEL event.. its only a squirt here and there, but they are saving each time, and able to use that fuel on the next straight. F1 also has the luxury of refuel and retyre.

F1 is also allowed to communicate with their drivers to remap on the fly. The rules state this ISNT allowed, but they "activate" different maps when required. Look at all the knobs on the steering wheel. You want to over take ? turn this, you want to draft for 2 laps to save fuel, click that, etc.. Motogp is fixed, there is NO "active" mapping allowed. The computer can decided what to do, and its been obvious honda has used it a few times. One time pedrosa got WAY out in front, then his bike was loosing .5s per lap.. It went into "fuel save" mode and just wouldnt allow him to use more power. It got him right out in front and helped him be smoother rather than harsh throttle in a pack, fighting for a place.

Theres more than one simple tactic. Theres dozens of ways around things. It really depends what sort a stuff you want to know. Have a look at indy cars. They cant "start" the engine unless the block is pre-warmed. The tolerances are so close, that unless everything is hot, its basically siezed solid. The blocks have a heating element thru it where they heat the thing up like a giant induction coil. Steel block and sleeves and ceramic pistons are the cause.

Hope this helps in some way

[davamb]

Thanks, seems like I was thinking along the right lines.

Sorry, one more if I may, but a lot closer to the subject at hand. Latest Sci Am has an article on all the improvements that could be done to the venerable IC engine to improve efficiency. Variable valve timing in one form or another is claimed as providing a couple of % efficiency improvement. One of these actuation methods was by solenoid, no camshaft whatsoever, just direct actuation of the valve by a powerful solenoid (and helper springs). Now in terms of flow efficiency is there any need to have a smooth opening/closing profile as provided by a cam lobe or if you could open and shut the valve like a switch would it make any difference to the gas flow? Might make a noisy top end is all I can imagine, but maybe there's some flow-related issue that I can't see - the end-over-end rolling mixing that you describe perhaps?

[Quan-Time]

solenoid actuation is nothing new. The Lexus cars have been experimenting with it for years. The main advantage is having variable lift, and variable timing. At max RPM, a really advanced cam, with a bit of overlap (exhaust and inlet both open at the same time) helps power, but sux for efficiency. It ends up putting fuel down the exhaust. Now have a really soft mild cam, with low lift, a passive profile, great efficiency, great cruising, but sucky on throttle response.

Solenoid actuators can change the complete cam profile on the fly. Great for low economy, high power, fuel save, etc.. BUT the solenoids break too quickly. Its why nissan and honda have electronic cam timing. It auto advances / retards the cam via a mechanism of their choosing.. Look into "VVTI" or BMWs "YANOS" i think its called. Kawasaki even has a hydraulic version on their ZX1400's.

[HansJ]

Aren't some MotoGP teams using hydraulic or pneumatic valve control as well?

[Quan-Time]

motogp almost exclusively use pneumatic now, except the ducati, which uses the "desmo" valve. From memory it was yamaha, suzuki, and then honda. But honda have been flirting with it on and off for many years.
Pneu valve isnt new. Its been around since the 70s. It works by having an o-ring in your head which the shim bucket is against, to form an air-tight seal. It runs at almost 30bar, which is... 14.7 X 30.. so lots. Its also a "loss" system, not "lossless". They store a little cylinder on board incase they get bypass, etc. They have enough storage in a cylinder smaller than a soda can to last a race. Its not practical for road use.

You guys are really testing my knowledge base aint ya !

[Tarwetijger]

Have you heard about the MultiAir technology by Fiat? It is (a kind of) a hydraulic system but very interesting. And for road use.
They can alter the opening and closing of the valves almost freely, a throttle valve is not necessary anymore.

[Quan-Time]

never heard of it, it was new to new.. Interesting concept, i cant see it going anywhere.. HUGELY complex, theres multi things per cylinder which can break down, and it will be patented to hell and back so no one will ever really use it.

Im still a HUGE fan of desmo.. Id LOVE to cast my own TRX alloy head with desmo compatibility in it.. I think it would sound awesome, and power would be sweet.. BUT thats making it more ducati than TRX..

Look up the 6 stroke "beare head" by Malcolm Beare. He has been in court for like 20 years with Jack Brabham enterprises over patent rights.. Pity, it showed probably the best usability of anything ive ever seen. But it will never see the light of day because someone wanted to steal it. Enter the shitty legal system.. Such is life.

[Tarwetijger]

never heard of it, it was new to new.. Interesting concept, i cant see it going anywhere.. HUGELY complex, theres multi things per cylinder which can break down, and it will be patented to hell and back so no one will ever really use it.

They already sell cars with this technology; the Fiat Punto Evo and Alfa Romeo MiTo.
(Specs in Dutch, but you'll get the numbers: http://www.autoweek.nl/carbase_data.php ... 7&cache=no)

Look up the 6 stroke "beare head" by Malcolm Beare. He has been in court for like 20 years with Jack Brabham enterprises over patent rights.. Pity, it showed probably the best usability of anything ive ever seen. But it will never see the light of day because someone wanted to steal it. Enter the shitty legal system.. Such is life.

6 stroke? hmm. Have to look that up.

[Quan-Time]

its a 4 stroke engine, but has a 2 stroke as the "head".. its upside down. So 2 pistons ramming each other. Its spastically efficient. So 4 + 2 = 6.. Not really 6 stroke.

AS for the fiats in production,, interesting.. I like the idea, but it just seems HUGELY bulky. But the proof is in there i guess.

[arrivisto]

interesting.. but it just seems HUGELY bulky.

Quite! I reckon that the Bishop rotary valve is the way to go, particularly as it has been shown to work reliably. The engine gets a higher rev limit and better torque throughout the range:

see: http://www.v-eight.com/multimedia/pdf/AutoTechBRV.pdf

There's no reciprocating valves, just a rotary tube. The engine becomes much more compact, and on a TRX, the engine could be mounted even further forward, giving a longer swing-arm. There would be more space above the engine, allowing a bigger fuel tank and/or a bigger airbox. The motor can even be made with the cylinder head is integral to the cylinder, eliminating the joint.

The more efficient Bishop-valved engine would produce less waste heat, so the radiator could be smaller; and if the waste heat output was sufficiently low, the TRX could have oil-cooling instead of water-cooling. (Even though water is a better coolant than oil in most respects, oil is more engine-friendly than water; and there would be one less circuit of pumped fluids).

[HansJ]

Wow, that Bishop thing was an interesting read! Geniously in it's simplicity!

[Killerwhale]

Wow, that Bishop thing was an interesting read! Geniously in it's simplicity!

Ahh, something like diz!

[Killerwhale]

Or this...

[dandywarhol]

The FIAT Multiair system is an electro/hydraulic operation through 1 camshaft not pneumatics.

The advantage of it is to introduce multiple valve opening phases to assist the "turbulence" effect as Quan was on about

http://www.autofocusasia.com/engine_cha ... nology.htm

I'm enjoying this thread - makes a change from some of the shite written on fora