ESE's works engine tuner

[Flettner]

I couldn't say; what is HR-HCCI?

I was hoping you might tell us what Harry Ryger's version of HCCI is and that it has been tested on other fuels

[speedpro]

... The Ryger engine makes us face the fact that conventional combustion is anything but perfect. ...

Which possibly goes back to a question I asked in the #6 thread earlier this month -

"I've been thinking about internal combustion engines and how they might be compromised by their mechanical architecture, being they have a crankshaft with a rod connecting to the piston. The piston reciprocates as the crank rotates. With an infinitely long conrod the piston velocity will vary sinusoidaly as the crank rotates. As the rods are a bit shorter than that the piston velocity varies at a modified sinusoidal rate. Over time we have optimised the combustion as best we can to extract as much power from the combustion as possible given the mechanical constraints of the piston rate of velocity change as the crank rotates.

My question is - "If" an engine could be built that could have any piston velocity change at any point of crankshaft rotation, what rate of change in velocity would be the best to extract the most from the combustion, firstly if we retained the current combustion chamber profiles with the current burn rates etc? If, as I suspect, that combustion chamber profile is a compromise to achieve a burn rate that best works with the current crank/rod/piston compromise, what then would be the ideal combustion chamber profile to achieve the ideal extraction of power from the combustion process, if we weren't restricted to the piston velocity profile but could in fact make it anything we wanted? As now I see it being speed dependant."

Engine speed that is. I've thought of a way to customise the piston travel versus crankshaft rotation and my machining/CNC guy says it wouldn't be too hard to make. Current thinking is for a conventional 2T cylinder on top.

[J.A.W.]

Which possibly goes back to a question I asked in the #6 thread earlier this month -

"I've been thinking about internal combustion engines and how they might be compromised by their mechanical architecture, being they have a crankshaft with a rod connecting to the piston. The piston reciprocates as the crank rotates. With an infinitely long conrod the piston velocity will vary sinusoidaly as the crank rotates. As the rods are a bit shorter than that the piston velocity varies at a modified sinusoidal rate. Over time we have optimised the combustion as best we can to extract as much power from the combustion as possible given the mechanical constraints of the piston rate of velocity change as the crank rotates.

My question is - "If" an engine could be built that could have any piston velocity change at any point of crankshaft rotation, what rate of change in velocity would be the best to extract the most from the combustion, firstly if we retained the current combustion chamber profiles with the current burn rates etc? If, as I suspect, that combustion chamber profile is a compromise to achieve a burn rate that best works with the current crank/rod/piston compromise, what then would be the ideal combustion chamber profile to achieve the ideal extraction of power from the combustion process, if we weren't restricted to the piston velocity profile but could in fact make it anything we wanted? As now I see it being speed dependant."

Engine speed that is. I've thought of a way to customise the piston travel versus crankshaft rotation and my machining/CNC guy says it wouldn't be too hard to make. Current thinking is for a conventional 2T cylinder on top.

Here's an interesting example of unusual 2T engine architecture, of ~bucket size..

http://www.odd-bike.com/2014/05/imme...of-design.html

[peewee]

not sure if you guys have seen these pdf files but i found them interesting although theyre a number of years old.



http://kth.diva-portal.org/smash/res...lse&sf=all&aq=[[]]&aqe=[]&aq2=[[]]

[Sketchy_Racer]

I thought they (rightly) separated motard style wide handle bars bikes from the rest of the rabble for safety reasons.

Yeah they usually do. This race day had a big hold up in the middle because of a bad crash, so they combined a lot of the classes so we could all get some racing in.

To be honest, it wasn't so much the riding style as much as it was the riders. Some of the guys on the motards are absolute muppets on the race track!

Good thing the NSR has the power to blast past them!

[Askor]

Some of the guys on the motards are absolute muppets on the race track!

+1 million

[Bert]

Yeah they usually do. This race day had a big hold up in the middle because of a bad crash, so they combined a lot of the classes so we could all get some racing in.

To be honest, it wasn't so much the riding style as much as it was the riders. Some of the guys on the motards are absolute muppets on the race track!

Good thing the NSR has the power to blast past them!

Man that's pushing the limits of the MNZ permits.....

Did Ross get the forth 300 out on Sunday?

[karter444]

Wobbly some time back you posted a photo of a crankcase you were welding up to reduce case volume but you also said that welding a plate over the crank half also gained a horsepower.I think you mentioned that this was common on kz2 engines . I may need to reduce the case volume as I have fitted a 7mm longer rod but an extra horsepower is always a benefit . will shrouded cranks still work with an engine with reeds at the rear as opposed to the kz2 with reeds at front in terms of crank rotation .
also did you have any problem with case distortion ,I was thinking maybe bolting the case to a 10 mm steel plate or did you have both cases bolted together ?
also whatgap is required between the two pieces being welded in . does it need to be only wide enough for the rod or as wide as the big end for efficient lubrication
cheers

[WilDun]

TUNISTI.
On the 'Bucket Foundry' thread they would be very interested in having some of your casting photos posted there too! - possibly we could have some sort of exchange between the two threads in future?
Well done you guys!

[Frits Overmars]

..If the combustion chamber profile is a compromise to achieve a burn rate that best works with the current crank/rod/piston compromise, what then would be the ideal combustion chamber profile to achieve the ideal extraction of power from the combustion process, if we weren't restricted to the piston velocity profile but could in fact make it anything we wanted?

Even if you could vary the piston velocity profile at will, you are still stuck with a finite burn speed - this is the decisive factor; not the piston speed.
The current combustion chamber profile is designed to create a highly turbulent flame front in order to promote the burn speed: the faster the better.
HCCI combustion is a quantum step forward, and as it does not depend on turbulent flame spreading, other chamber shapes may emerge.
It's one of the things that may still be optimized for the Ryger.

[MotleyCrue]

Even if you could vary the piston velocity profile at will, you are still stuck with a finite burn speed - this is the decisive factor; not the piston speed.
The current combustion chamber profile is designed to create a highly turbulent flame front in order to promote the burn speed: the faster the better.
HCCI combustion is a quantum step forward, and as it does not depend on turbulent flame spreading, other chamber shapes may emerge.
It's one of the things that may still be optimized for the Ryger.

Then is it fair to say that at some normal operating conditions perhaps even full throttle the Ryger engine is not using the spark plug in any meaningful way to initiate the combustion process ? The plug is initiating combustion for engine starting and maybe low load, but is irrelevant at high rpm full load ?

[Frits Overmars]

Then is it fair to say that at some normal operating conditions perhaps even full throttle the Ryger engine is not using the spark plug in any meaningful way to initiate the combustion process ? The plug is initiating combustion for engine starting and maybe low load, but is irrelevant at high rpm full load ?

Maybe so; there are lots of things I'd like to measure but it would require more instrumentation than we have available at the moment.

[Tunisti]

Hmm.. I think that there must be somewhat dirty mixture inside the barrel, when all ports have closed. At least if the combustion is somehow sorted as knocking. Haven´t really figured out, but I have a theory that mixture involving exhaust gases tends to have lower peak temperatures and the "flame" speed of "knocking" is reduced to moderate rate via the impurities bethween ignitable "packages". This would not only lower the NOx emissions, but also allow leaner mixtures to be used -> reduced HC emission.

If the knocking-like combustion would occur in pure charge, there would be large broblems with heat and shock-type stresses to mechanical parts. I remember Frits or Jan talking about the knockings effects on macroscopic levels: The shock waves tend to "blow off" a thin layer of insulating gas from the metal surfaces (ie. piston), introducing the surfaces into situation where the heat conductivity increases significantly. I wonder whether the Ryger concept has some kind of trick to keep the insulating layer of gas on the surfaces, despite the exposure to shock waves.

And then there´s the theory, that spark plug would give many sparks or one "conitnuous" spark, meanwhile there would be huge squish velocities forcing the charge right into the spark gap. Meaning that the flame speed would be artificial or the charge would be ignited in several points (spark plug stays in place, mixture to be ignited moves due to the shape of cylinder head). At least, the melting of the electrode would be an issue to be considered, when knocking-like combustion would occur with fresh mixture... Continuous or multiple sparks could also build up excessive heat to the electrode, I guess...?

Btw. I´m about to order some 20kg of Vinamold. I was wondering whether to buy only red, yellor or half and half both of them. I would need to take some castings from exhaust- and transfer ducts, but I don´t have a clue how well the yellow one wants to settle in the duct and how hard it is to get out of there. On the other hand, I don´t know how floppy stuff the red one is, since it`d be bad thing if the castings would bend under their own weights. My plan would be to copy the Vinamold pieces into plaster of paris, so it is important that the pieces would bend as little as possible. Any tips what to do?

Thanks for the comments! I´m going to post some DIY casting reports to Bucket Foundry topic, after I´ve translated them. Where should I post step by step instructions/reports about manufacturing of hydroformed exhaust pipes?

Btw. How much do I have to spam, before I can send private messages?

[TZ350]

Btw. How much do I have to spam, before I can send private messages?

About 10 I think. Love your pictures thanks.

[Grumph]

Thanks for the comments! I´m going to post some DIY casting reports to Bucket Foundry topic, after I´ve translated them. Where should I post step by step instructions/reports about manufacturing of hydroformed exhaust pipes?

Btw. How much do I have to spam, before I can send private messages?

Start another thread on hydroforming. It's been talked about on this one a bit but it's specialised enough - and enough are interested - to warrant it's own thread. And it gets your post count up as well....
Nice to see what you've done. Good work. Those long winters in Finland are obviously productive....