Ha,Ha! - Very good Frits!
Earlier on somewhere (in the "oddball" thread ?) I did after all support that guy on you tube talking about bike engines and not giving a stuff what people thought of his comments!
Slept in this morning and was obviously in a melancholy mood!- no, not a hangover (you don't get hangovers if you barely drink).
While the gist of the rant was true & correct, as the day wore on my perspective of the situation changed! so I decided to battle on a while longer - can't just throw in the towel and miss out on all the foundry work and never get to see my major breakthrough in action!! - still probably got time to have a shot at it!
BTW, What will be the benefit to the fresh charge if it is intermingled with residual exhaust charge? - extra heat? still burning charge? I see the point in Neil's timing piston giving a precise time to the start of combustion (control of which seems to me to be important!) and this could be controlled, but I fail to see how the residual exhaust gas can be used to control timing of the combustion! - maybe I'm blind.
I think I did make a slight mistake when I asked earlier if the timing would be controlled by fuel injection, as in a diesel (on HCCI?).
As for a hyper rotational speed crankshaft driving a reciprocating piston?..... I do have my doubts!
But, as always, I could be wrong!
NEIL, I did see that video before and was quite impressed seeing it actually work.
Strokers Galore!
small piston was like 5mm stroke or somthing I think in that engine. New engine has 16mm stroke, still not much.
Surprise - Bradshaw was playing around with bleeding exhaust into adjacent cylinders in the mid/late 50's. He had a 4 cylinder Ford Consul going as well on the road as a family member's Zephyr 6 - Yes Will, you and I remember them, lol. Ford were interested enough to cast up a block for him with provision for the needed ports. Benefits were economy and better acceleration. Harry Ferguson was interested amongst others. Bradshaw took out patents.
I've loaned my copy of the Bradshaw book, when I get it back, I'll post what's there.
Yes Grumph, I remember the Ford Consul well! - steering shimmy was the order of the day and if I rightly remember those bloody unbelieveably stupid vacuum wipers!
Bradshaw a clever engineer (till he actually made one or two great cockups) and Harry Ferguson's extremely successful Ferguson tractor, produced by taking advantage of Edsel Ford's big cockup of using Ferguson's hydraulic system on the Ford (2N ?) tractor, thereby ending up by having to hand over the complete package to Ferguson who eventually fitted it with the then new (and eventually very successful) Standard Vanguard engine and I think a David Brown gearbox and the rest is history! - now what were we talking about?? - ah yes, HCCI!
Neil, I musn't have been paying much attention at the time you were playing with your OHP? engine and I had no idea that it had such a short stroke. I do hope that it works out well with the new one! - does this suggest that the charge needs a swift "kick in the guts" to set it in motion? - How about a half speed 180 deg twin up top to make me feel more at ease?![]()
I must be thick, because I still can't see how residual exhaust gas in the cylinder can make the HCCI thing happen at a precise time if the exhaust gas is coming back from the pipe - to me it all seems a little vague (despite Frits's simple formula to explain what makes it happen).
There must surely be a right time for this to happen and this timing surely must vary according to what is required of the engine at various times?? - just as in common or garden spark initiated combustion.
I feel that some form of reasonably precise timing is required in all engines, from extremes like small model aircraft "diesels" which just rely on compression (but still need to be set by a manual screw adjusted static contra piston) to modern automotive diesels using high pressure common rail fed injectors, probably using computer controlled timing (I don't know).
By the same token, doesn't this issue also need to be addressed in the case of HCCI.
If I'm wrong then would someone who has a handle on it, please explain it to me in simple terms (and perhaps talk more slowly) and maybe I'll finally get it and accept it!![]()
Strokers Galore!
Awesome channel. A true blue retired Aussie foundryman
https://www.youtube.com/channel/UC90...SRF18jAG0HIA6g
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Kinky is using a feather. Perverted is using the whole chicken
As I wrote yesterday, the optimum timing for the onset of HCCI combustion is controlled by pressure x temperature. Fletto does it via the pressure, with his small double-revving overhead piston (I never dreamt that I would write 'overhead piston') that gives a sharp pressure-rise right before TDC.
The alternative is raising the mixture's temperature to a fraction below self-ignition by adding a controlled amount of still-hot spent gases and let the normal pressure rise near TDC do the rest.That is what the car manufacturers are investigating. Hence their claims that HCCI needs exhaust gas recycling and can therefore only be done at part-throttle. Neil has already proved them wrong.
Thanks Frits, I'm now getting up to speed on the subject - yes Neil is certainly doing a lot of research not only for himself, but also for the manufacturers research teams who (unfortunately) will no doubt be taking note of his failures/successes!
You just answered an earlier question, ie when I asked if it was heat in the charge, or actual "still burning" mixture which was required - I feel that it would be a little hard to control that combined with fixed pipe characteristics, but now I remember Honda were experimenting with modified power valves a while back, I didn't pay much attention at the time though - of course we really need to remember that not every two stroke will be used for competition, most won't in fact! - maybe an inappropriate statement in a bucket Racing thread!
Neil, why do you need to use double speed (OHP)?
Husa, thought you were suggesting that I was getting off topic and you wanted to get back to foundry !!
Strokers Galore!
Will, using exhaust gas to set off HCCI is in fact quite difficult. Needs to be controlled very well so as to not destroy your engine. I guess that's why there hasn't been any commercial HCCI car engines until now, electronic control has grown up and as I understand it, its a cruse only operation, full throttle is as normal with spark plug. Don't know about the Mazda one yet.
My little rig was just a 'lets see what we can achieve' project even I was a little stunned it worked first off. This has lead to a much better version (with actual control) but still just shade tree tinkering really. It's nothing without real test equipment.
Little piston needs two to one to get the rapid compression rise at the right time. A cam would possibly be better but I'm buggered if I'm going to be responsible for an over head cam twostroke
Note, first version was going to be three to one.
Will I've got too many things on my plate, this jolly old gyro engine was supposed to be nail up and flying by now but it just won't go away. Spent yesterday quietly going over the ignitech setup and found a few things, First, the cheap arse coils I was provided with the unit I can't trust. One having a semi failure, sometimes will conduct, sometimes won't (depends on how you hit it with the hammer) it's vibration dependent. Second, (Frits) you must use resistor plugs and caps! Now my timing light will work
Third, it's important to have the correct trigger to flywheel gap. Fourth, I still struggle with the this base timing thing, sorted now, possible had a little much advance before ( I know I did.)
Also now the ghosting on channel two is gone, that's the one that had the doggy coil.
It can be frustrating fighting against your own stupidity (and possible some pigheadedness), instructions, what do they know!
So there you go faith restored![]()
Instructions are only the manufacturers opinion as to how their product should work...
When the Boyer-Bransden ignitions were new to the market, no less a person than Paul Dunstall managed to blow a unit while installing it.
He found a path to earth that B-B hadn't forseen - himself...Came as a bit of a shock apparently, to B-B and Paul...
They changed the installation instructions forthwith.
Just wondering if, at the part load HCCI operating regime, that if one could simply turn on the "glow plug(s)" to provide some additional extra localised heat to initiate combustion. No idea if it would have enough thermal capacity though. Alternatively a retractable "hot spot" shaft(?), utilising the heat from the previous cycle (whether it was HCCI or not).
Cleaned up the shitty lead casting and with a bit of spot putty and primer, looks half way reasonable, good enough for an initial assessment.
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"Success is the ability to go from one failure to another with no loss of enthusiasm.”
Frits, but when I start to talk, the governor jams and as a result I have to go back over everything and repair the damage!
In that last picture and quote by Einstein, he looks like he is wringing his hands in despair!
Thanks for the kind words though!
Ken I reckon that isn't a fishing lure at all, I think that its a new Burt Munro style streamliner shell for that three wheel wonder wagon of yours!
Flettner reckon you should concentrate on the gyro engine, after all it's just about there!
Thanks for the info - whether or not I can use it I dunno, but it's bloody interesting!
Strokers Galore!
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