It's certainly true with conventional engines - it alters the volume of the combustion chamber and therefore the compression ratio. (The volume swept by the piston stroke remains unchanged)
It's rather like having a warped head skimmed true. This also alters the compression ratio.
Diesel engines have had fuel injection from the beginning. Petrol engines had carburetters first. There is a difference.
The Wankel rotary engine has no removable cylinder heads. Actually, it hasn't got a cylinder head as such. It does have a combustion chamber, of course. If memory recalls, it has a rotor with lobes. You need to read up on it, to understand its very unusual design concept. This engine bears no resemblance whatsoever to the usual piston engine. It doesn't have any pistons.
I need some time to think about this. I may not be able to answer you. I _did_ know, but my memory has probably let me down.
Sylvain.
Not that many to be honest.
Biggest leap was electronics, to replace all that nasty carb/distributor rubbish with a nice bit of ROM...but honestly, the rest has all been around forever, its just not been cheap enough to be worth doing until legislation forced it on us.
Mainly material technology has been the biggest thing, and precision CNC machining.
Only about 70 years I suppose.
I wonder when petrol injection came in, then.... would it have been in the 1920s? I was just saying that the concept is old - improvements in manufacturing and materials make old ideas viable. There aren't very many new ones!
That's why I said that might be true for *some* engine designs.
If you'd like to see an animation, there's one at:
It's sort of a joke question, really... the answer is there, though!
You're joking right?
I know that too well. I was at a dealers the other day picking up some parts (which actually were reasonably priced) and everyone who came in through the door while I was waiting for ages to be served had a problem with the work that had been or was supposed to have been carried out. This was in Stevenage but it's been the same story at every dealer I've been to.
I had a look at the filler cap today and it says "95-98"
It was certainly in use in some pre war aircraft engines...
I'd say its still a 4 stroke, in that the induction and firing cycles are done in two volumetric compression expansion stages.
Depends on how you define 2- stroke/4 stroke.
I think that it came much later. 1970's ?
Sylvain.
Sylvain.
No - you will get a reply. May not be what you want to hear, though. ;-) At least it's free.
Yup. Same here.
Have you tried a specialist? My initial thoughts are the knock sensors aren't doing their job. I can recommend AMC in Garratt Lane Tooting as being honest and competent. 020 8944 9966 I've seen M3s in there.
Think it's regarded as a two-stroke.
In a piston engine, this is very clear.
4 stroke: Induction stroke, compression stroke, power stroke, exhaust stroke. 2 stroke: Combined induction and compression stroke, combined power and exhaust stroke. Usually, there is a transfer passage between the crankcase and the cylinder to make this work. A refinement is to use a secondary piston to open the transfer passage port, independently of the primary piston (Puch 175cc engine, of Austrian manufacture).Sylvain.
It's not free as it costs me my time and stress in having to list the problems and a catalogue of errors by the dealers. The last incident was when I had to take the car back three times after BMW service had damaged it (and not told me) and that includes taking it back after the bodyshop manager and the customer service manager had insepcted the vehicle. "The least we can do it put the problem right" is what they said and yes that was all they did. Oh, apart from backing down on a warranty claim I was making when they were trying to convince me that the items weren't covered.
Quotes from BMW "All M3s drive like a pig until they're warmed up" "M3s are really fussy on octane" "We always get people who buy them bringing them back but the problems aren't problems they're a characteristic of a performance car" "There are no faults stored so everything must be ok"
The car does run fine on 99 and OK on 95 but at low rpms (on 95) it sounds like the gearbox is about to fall apart.
That's electronic injection (EFI) Mechanical systems were in use before WW2 on some racing cars. And on aero engines.
I've looked at that animation. As it's a rotor, and therefore has no piston; we cannot talk about the number of strokes per revolution. That HTML mentions the Otto cycle (4 stroke), and states that the Wankel engine has one power cycle per revoluton of the rotor. I'll settle for a 4 cycle engine. :)
Sylvain.
2-atrokes have one power cycle per revolution.
I'm aware of that, and went into some detail in one or two previous messages.
As for the Wankel engine, I've said "I'll settle for a 4 cycle engine". This is not meant to be taken as a firm statement, as I didn't really need the info and didn't have enough motivation to read more about it.
Sylvain.
Analysis of the gas cycle says its a 4 stroke, tho a 2 stroke might be makable..if indeed 'stroke; is a term you can apply to a machine that doesn't have a linear piston in it.
Its just that there is an induction and a power stroke per revolution of the main rotor..which is geared down to the shaft anyway....
Call it 4 cycle and avoid confusion, Induction,compression, power and exhaust. Albeit that the combustion 'chamber' is a movable feast.
Wankels are like the old aero engine sleeve valve engines. Lots of advantages, but let down by difficulties with sealing the things against oil loss.
In the end better materials and conventional layouts make the ordinary engine a more practical proposition.
It's a grey area - I wasn't really arguing either way, just mentioning one of the factors.
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember EricP saying something like:
Factual bollocks, you mean.
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember The Natural Philosopher saying something like:
It isn't superfluous at all; it's just as important.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.