[Kipper]

my electronic fuel injection are ready to be tested. it is originaly designed for dirtbikes and ATVs but it could works in any 4 stroke engine.

it will be ideal for my prototype engine.

i have order some custom enclosures from a rapid prototyping supplier, it is really fun, it is easy to build very complex parts in some days!




Jlcortex
http://www.sportdevices.com/jlcortex/

I'll take one

[Eson]

...
Anymore, it is NOT that difficult to get poppet valvetrains to run and live at engine speeds of 9000+ rpm...

IF ANY concept had the budget of HUNDRES of racing teams, THOUSANDS of car companies and more then 150 YEARS of time you can make ANY concept VIABLE. F1 is a BAD EXAMPLE because of CONSERVATIVE rules and they FORCE the way of developing in ONE direction.

Do YOU think poppet valves were FLAWLESS and could run for ages in the beginning?

[turmite]

I have nothing to give as far as input goes, but I would like to commend all of you that have posted for keeping the thread civil when some would have flamed away!

This has been a most interesting read. BTW NC, I always look forward to reading your posts, probably because I'm an old codger myself!

Mike

[HAASboi]

nice ECU jlcortes is it match for my 4 stroke scooter?

[NC Cams]

Memo to Eson RE Poppet valves:

I can't say that I had much of a vision into the viability of poppet valves over say rotary valves. Why? Mainly because i came into existance and developed an awareness of poppet valves well after they had been well and deeply invovled into their development cycle. Since the market was there and they needed engineers to support it, I took interest and cast my lot in that direction.

Besides, part of the wisdom in getting involved with a development process is to choose a technical field that A) has develoment potential and B) is not fraught with insurmountable technical challenges and C) has market potential/demand for the technology. Once could say that poppet valves are to VHS as rotary vavles are to Beta or , better yet,kinnescopes. One became the commercial success but the others essentially orphan technologies who's time has perhaps come and gone.

Poppet valves have had their share of challenges. Fortunately, the development of martensitic stainless and, perhaps more importantly, austenitic stainless steels had as much if not more to do with the development potential than anything else. Modern machining and heat treating further advanced the technology which, literally evolved from that of creating nail - one of the premier valve suppliers in the USA had its roots in the field of construction nail and rivet forging/heading.

Essentially, the poppet valve is psuedo digital in that it is open or closed - yes, you have partial flow potential but you have the benefit of sealing surfaces that are not frictionally rubbing with respect to each other which REALLY simplifies the sealing process - especaily when it comes to wear.

Any time you have parts that have to spin or slide move with regard to each other, clearance and lubrication are needed to prevent siezure. One might say that the very things needed to make a rotary valve functionally viable are EXACTLY the same things that will hamper/hurt the ability of the device to seal which is a prime function of ANY valve for an IC engine. The need for the part to "live" under such duress also needs to be a concern.

The very nature of the poppet valve acually causes it to increase its sealing potential during combustion at pressures that can spike to 1200psi or more and at temps of 1400 deg F or more. On the other hand, these same pressures/temps are trying to unseat the sealing potential of the rotary valve. Perhaps this is why the concept has not had a lot of successful development - the task is essentially a continually effort to prevent the engine from hurting its valve sealing capability instead of enhancing it.

Yes the concept has a lot of charm. Yes it has a lot of "potential". Then again, so does alchemy wherein one tries to turn lead into gold. The atomic make-up is so close it is scarey (only one electron or so different) but yet, in spite of centuries of effort, it still hasn't been done.

The budding tinkerer and/or developer should not be disheartened by the unsuccessful efforts that have occured with rotary valve engines in the past. Perhaps there is a genius out there who can figure out how to achieve the holy grail. In the mean time, I'll continue on with my studies and efforts toward creating devices that open and close poppet vavles - the market and need for continuing development in this area is still quite substantial and new developments are continuing to emerge.

[IgorWojas]

Well I'm 100% sure You are right but i will still search for the solution. Next thing i found is that almost every model 2-stroke uses rotary valve. Of course its not having any contact with the combustion chamber but its still a rotary valve

[NC Cams]

Memo to Eson RE Poppet valves:

I can't say that I had much of a predictive vision into the viability of poppet valves over say rotary valves. Why? Mainly because I came to know or their existance and developed an awareness for same well after they had been well and deeply invovled into their development cycle. Since the market was there and they needed engineers to support it, I took interest in and cast my lot in that direction.

Besides, part of the wisdom in getting involved with a development process of a technology is to choose a technical field that A) has develoment potential and B) is not fraught with insurmountable technical challenges and C) has market potential/demand for the technology.

Once could say that poppet valves are to VHS as rotary valves are to Beta or , better yet,kinnescopes. One became the defacto commercial success but the others essentially orphan technologies who's time has perhaps come and gone.

Poppet valves have and surely had their share of challenges and continue to do so. Fortunately, the development of martensitic stainless and, perhaps more importantly, austenitic stainless steels had as much if not more to do with the development potential than anything else.

Modern machining and heat treating further advanced the technology which, literally evolved from that of creating nail - one of the premier valve suppliers in the USA had its roots in the field of construction nail and rivet forging/heading. The contemporary development of advanced flow techniques was clearly enhanced by SuperFlow and their racer focused flow benches. TRW's development of the titanium valves in the late 60's/early 70's had as much as anybody to do as anything with the development of ulstra high speed poppet valves as any technology that has even been devised.

Essentially, the poppet valve is psuedo digital in that it is open or closed - yes, you have partial flow potential but you have the benefit of sealing surfaces that are not frictionally rubbing with respect to each other which REALLY simplifies the sealing process - especaily when it comes to wear.

Any time you have parts that have to spin or slide move with regard to the adjoining sealing surface, clearance and lubrication are needed to prevent siezure. One might say that the very things needed to make a rotary valve functionally viable are EXACTLY the same things that will hamper/hurt the ability of the device to seal which is a prime function of ANY valve for an IC engine. The need for the part to "live" under such duress also needs to be a concern which is probably why rotary valve technology has remained so elusive.

The very nature of the poppet valve acually causes it to increase/enhance its sealing potential during combustion at pressures that can spike to 1200psi or more and at temps of 1400 deg F or more. On the other hand, these same pressures/temps are trying to unseat the sealing potential of the rotary valve.

Perhaps this is why the concept has not had a lot of successful development - the task is essentially a continual effort to prevent the engine from hurting its valve sealing capability instead of enhancing it.

Yes the concept has a lot of charm. Yes it has a lot of "potential". Then again, so does alchemy wherein one tries to turn lead into gold. The atomic make-up is so close it is scarey (only one electron or so different) but yet, in spite of centuries of effort, it still hasn't been done. Does that mean you should quit trying? Sometimes, all the effort in humanity can't make one's wishes come true. Perhaps rotary valves may ultimately be the "alchemy" of the IC engine community - then, maybe someday, not.

The budding tinkerer and/or developer should not be disheartened by the unsuccessful efforts that have occured with rotary valve engines in the past. Perhaps there is a genius out there who can figure out how to achieve the holy grail of getting conflicting needs to ultimately work to each other's benefit.

In the mean time, I'll continue on with my studies and efforts toward creating devices that open and close poppet vavles - the market and need for continuing development in this area is still quite substantial and new developments are continuing to emerge.

[NC Cams]

Re: rotary valve 2 Cycles - You have to be carefull about the symantics and what's really going on here.

2 cycles have used low pressure reed or rotary valves to seal the air that is pre-trapped/contained in the crankcase for decades. BUT, BUT the high pressure gasses that are created/generated during combustion are actually "piston ported".

That is, piston position ultimately opens and closes the intake and exhaust ports (unless of course you use poppet valves which the 2 cycle Detroit Diesels used for years on the exhaust side along with piston ported intakes). With piston porting, the pistons and rings do the combusion sealing, NOT the reed or rotary valves.

In todays IC engine community, combustion efficiency is becoming more and more critical as fuel prices soar and emission laws dictate more and more that previously sloppy combustion engines "clean up their acts". This is why compact, good burning SMALL combustion chambers have gained favor. Big chambers or ones with stagnant or hard to reach/burn areas are NOT well suited for optimum engine efficiency.

Yes, even the motorcycle community is feeling the pinch of emissions legislation. This is why 2 cycle power houses are being mothballed albiet in favor of larger displacement 4 strokes. Don't be surprised someday if emission checks become the norm for race engines as the politics of emissions and fuel economy will eventually reach into the racing community.

I can recall the fuel crunch days of the early 70's. Even NASCAR shortened their races in response to the fuel crunch. The evolution from big to small blocks was done for that reason as well as to slow down the cars. The good old days of unlimited power from high compression, leaded fuel engines, even in F1, have come to an end. Even F1 is looking at V6's with greatly limited fuel budgets to force the development of more efficient engine and power management technologies.

Remember, the prime objective of the car companies that get involved in racing (outside of Ferrari) is to sell production cars. It would seem logical that the high buck R&D that they dump into racing should be of value EVENTUALLY to the production vehicles that they REALLY are in business to make/sell.

The turbo diesels that both Pugeot and Audi are running at LeMans this weekend are both examples of what can be done with mundane technology taken to extremes. Wanna bet that both car companies have stellar production diesels that avail themselves someway/somehow of the race car engine technologies???? If not now, they eventually will.

Before the flames start on diesels, i have a tremendous amount of respect for them - especially the Audi and Pugeot race cars. They are torque MONSTERS and show clearly that this essentially unrespected "truck engine techology" (how its looked at in the USA), can and will be made suitable for sport and racing car use.

The TDI diesel engines CLEARLy show that you don't need ultra high RPM rev potential gasoline fueled IC engines to make powerful, fuel efficient and emissions capable engines. When I last looked, the TDI Audi's were running 1, 2 and 3 at LeMans and they were easily outrunning the Pugeot's that out-sprinted them during qualifying.

Overall, don't underestimate the Audi's. Detroit better hope that they never decide to go NASCAR "taxicab" racing. I"d love to see it, especially with a liberal engine formula BUT with a very closely managed and declining over time fuel budget. Make all the power you want, any way you want - the race is still 500 miles long but you only have enough fuel to run 480 then 460 then 450 and so on. Deal with it.

Wana bet the cars will still be fast AND fuel efficient and not that much slower than they are now???

[IgorWojas]

Yes I know that, and i can see what's happening with sport cars. Here in poland we say "need is mother of invention" and that's true looking at the development of engines. I don't like diesels but I know that the potential of diesel engines is big. In fact there are more then 70% of cars running on diesel in poland now, its waaaay cheaper and today's diesels can greatle compete with gas cars. But there is one small problem, when comparing diesel to gas : All those diesels are TURBO diesels and these are compared to NA gas engines... This is not really fair when talking about performance not fuel efficiency...

[Kipper]

But there is one small problem, when comparing diesel to gas : All those diesels are TURBO diesels and these are compared to NA gas engines... This is not really fair when talking about performance not fuel efficiency...

You could argue that comparing a 4T to a 2T isn't fair either..or that petrol (gasoline) burns easier than diesel....



Jlcortes will you be making your own piston?

[NC Cams]

"Fairness" is a relative term when it comes to thermodynamic effiency of gas versus diesel engines.

Gas engines are spark ignited, diesels compression ignition. In gas engines, you need a highly knock (self ignition) resistant fuel so that it won't ignite prior to the introduction of the spark. Thus, the compression ratio has to be limited so that you don't exceed the knock potential of the fuel.

Diesels on the other hand, rely on high cyl pressures and the resultant increase in the air temp via compressive work to raise the air temp to that which is high enough to self ignite the fuel when it is injected into the chamber. Since the diesel doesn't have to compress a fuel air mixture, only air, the more you can compress it the more net power can be released when fuel is ingested and burned.

Since the diesels are extracting work from the exhaust gasses, they recover what is being wasted by the gasser. Moreover, since the diesel fuel has a higher BTU content per pound of fuel, it has more energy potential. As I recall, diesel fuel is a lower temp distillate of the raw oil hence it takes less energy to refine it.

Gasoline engines came along at the right time as, initially, gasoline was burned off a a waster product of the refining process. Luckily, gas engines love the stuff and since the fuel was cheap and plentiful, gas engine development thrived to take advantage of the cheap source of fuel.

Things are different now. It now behooves us to develop diesels as they are thermodynamically more efficient creators of power. It is easier to extract gobs of power from the fuel once you figure out how to burn it cleanly and with minimal emissions.

If you really want to see some interesting development in the race community, try this: run what you brung to the race - gas, diesel, big or little CID, I don't care.

However, you only get so much fuel (like enough to run 400 with todays power levels) and the race will still be for 500 miles or whatever. Want to bet the cars will still fly and ultimately get good mileage too???? One more thing, no more spoilers or "un-natural" add-on aerodynamic wings and such. Back to more efficient CARS, not wind tunnel wonders.....

[panaceabea]

wonderful thread, will have to read it two or three more times to absorb

[volkl_ac3]

Hey guys,

I have a quick question regarding regular street motorcycle engines that rev in the range of 14k. Do they use the pneumatic valves, or regular spring valves?

Thanks

Sebastian

[NC Cams]

Pneumatic valves are not typically used in production engines - too expensive and not good for long term, install it and forget it operation.

These are more likely limited to F1 levels of engines where the ULTIMATE in performance is needed for a relatively short operating period, followed by regular and necessary maintenance and rebuilds.

More likely than not, your 14K rpm street or production race bike is using springs in concert with titanium valves and retainers and other light weight, proven durable items.

[elmerfud]

Honda cbr250 revs to 19k with steel valves and valve springs! I had one that had done 60,000kms and it still wouldnt blow when taken to redline, the valveguides suffered and so to the head gasket, its all been done before by people much cluey-er than me, my tip, buy a blown cbr250 motor for $100. measure and weight the internal bits and from there you can build a *****in half scale F1 v10, 72' like a renault easy, or hard 90' like ferrari.
Thats my dream, anyhows.

[svenakela]

Wow, how did I miss this thread!

I just wanna pop in with a comment on desmo's. The main reason why Ducati designed the bikes with desmo technique back in the days was the springs. Back then the springs were not efficient enough and the desmo engines were running with a lot higher top RPM. Today, they do it because it's a part of the brand. The day when Ducati starts to design bikes without desmodromic systems - it's not a Ducati anymore.
And yes, the Desmosedici is a desmo-engine, and how I love the sound from it!

Springs are as good as desmo nowadays. The latest Yamaha R6 model is redlined at 18 000, and it's a production bike...

Good luck with this project, I like craziness!
Sven

[elmerfud]

Hi Sebastian,
Here is your's / anybody's cad images, please no emails. I am over this thread.(wedge)

[PoWaKiD42]

my electronic fuel injection are ready to be tested. it is originaly designed for dirtbikes and ATVs but it could works in any 4 stroke engine.

it will be ideal for my prototype engine.

i have order some custom enclosures from a rapid prototyping supplier, it is really fun, it is easy to build very complex parts in some days!




Jlcortex
http://www.sportdevices.com/jlcortex/

Hi, where you will buy the injector? how do you programme the injection? it comes with some kind of software?

[an0n]

This project looks really nice!, I hope you will update with your latest progress soon

[racecomp]

NC CAMS: An engine "lives" when it can run with NO maintenance for long periods.

Dont tell a top fuel engine builder that!!! His engine will only just last one pass, during the pass it will only do about 750 revolutions give or take a few rev's from stat to finish on a good run and then it will be pulled apart again.....

It's been a good read; why not just make a two stroke engine? You would make the sort of power that you are after relatively easy compared to a four stroke.....

I can help you with a fully programmable ECU that can look after fuel injection, ignition and cooling fans that will adapt to any motor 4 or 2 stroke; it's just like a Motec but for a 10th of the cost.... Interested????