One of my minor but stranger obsessions is the micro cars produced in Germany in the 1950's. The most succesful was the Goggomobil with a rear mounted 600 cc two stroke. One version had an electric pre selector gearbox by Getrag. I suspect you could argue this was the first " semi automatic F1 type" box ever produced as I beleive it had dog selection via solenoids.

However even more innovative in a way were the two stroke engines in the Goliath and Gutbrod microcars - the sports versions had direct fuel injection by Bosch before the Mercedes 300SL. Bosch had developed direct petrol injection for WW2 but those were 44 litre engines run mostly at high power. The Goliath DI had to inject the tiny amounts of fuel to run a 600 cc two stroke at idle.

What is sort of interesting was that Bosch were trying ( way before CO2 etc!) to get around the fuel consumption problems of a two stoke by only adding fuel after all the air/exhaust gas mixing was largely over and so eliminate the unburnt fuel out the back problems of two strokes. If they had also gone to non petroil lubrication they would probably have had a quite efficent engine back in 1953!

Given the cars weighed about 400kg 70 mpg ( imperial) was probably within reach based on the 60 mpg of a carb. fitted Goggo.

Sadly Goliath and Gutbrod folded so the 2 stroke DI approach never went further.

I believe that direct injected 2-stroke engines represent the future of the IC engine, especially for public use. The power density and efficiency of the setup are just too good to ignore. I am honestly surprised there are not already many such engines available to the public, especially in diesel form as series hybrid generators...

You're getting silly Mate, you seriously can not post and think that many manufacturers haven't investigated a cheaper more powerful engine form such as 2 strokes and rotaries.

Research Honda EXP2 400cc 2 stroke motorcycle and Honda CRM 250AR.

A few years ago I went to a few Chinese car companies with a friend from Orbital (he runs the tech side of Sprintex Superchargers now) and the story from them was all the same - "get us Euro 4 (and later 5) compliance cheap diesel and we'll buy everyone you can supply", they are still waiting.

when I was at Ford several years ago , the engineers said that the orbital engine was rejected because the engines would not last much over 50K and it was due to the oil starvation to pass the regulations of the time. total loss system employed, they should have gone the wet sump supercharger route. There was a small valve in the bottom of the sump that would drain off excess oil duing prolonged idling to prevent a surge of oil dissapearing out the exhaust when you accellerate when the lights go green.
I have an interesting story to tell one day regarding the shenanigans that went on involving my design , but you may get a hint from this
http://forums.autosport.com/index.php?show...143875&st=0

there was also the Ficht direct fuel injection 2 stroke, invented by guys in east german trabant factory, used by OMC and later Evinrude for 2 stroke outboards... Ingeniously simple, and efffective, but I remember them having allsorts of problems in day to day use dunno what happened afterwards..

The Goggomobil used engines with displacements of 250, 300 or 400 cm3. Also, Goliath (part of the Borgward group of companies) folded long after abandoning two-stroke engines. Also, as DI engines, the Gutbrod and Goliath could NOT use petroil lubrication, an oil injection pump was part of the system. A very detailed description, complete with illustrations, of the Bosch DI system and its components, can be found in Ing. Trzebiatowsky's classic work "Die Kraftfahrzeuge, und ihre Instandhandlung".

I didn't mention rotaries, and in my opinion current forms of direct injection change the game when it comes to 2-strokes (which has only recently become commercially available as a viable, available fuel delivery system).

And YES, I can seriously say with complete confidence that companies often throw out superior designs to protect egos and investments. All you have to do is know the history of the commer ts4 to understand this. I am sure most stories like the ts4 never even see the light of day. Often old, entrenched executives, engineers, and CEOs simply bury things that might reveal their incompetence, or lack of vision, or the fact they are stuck in a certain era of technology and are threatened by change to what they are familiar with...

Even previously (relative) more expensive DFI system would be easily covered by the savings of no 4 stroke valve train. DFI is in no way a new thing either.

So now that many manufacturers are converting to DFI why haven't they all gone to 2 strokes?

Thank you, that is so logical it should have gotten into even my thick skull!

The only description I have of the Goliath/Gutbrod system is in a fuel injection book - is there an english translation of "Die Kraftfahrzeuge, und ihre Instandhandlung"by any chance?

Being english and not able to read German (!) my sources are limited on Goliath, I have a listing of a 1957 Goliath with a 900 cc 2 cylinder engine, would that be a 4 stroke and not a 2 stroke then?

Good question Cheapy. I have no idea, it makes lots of sense that they do go to two strokes.

http://en.wikipedia.org/wiki/Rolls-Royce_Crecy

Check out the engine spec on this baby in 1940s.

That is addressed in my comments here:

"And YES, I can seriously say with complete confidence that companies often throw out superior designs to protect egos and investments. All you have to do is know the history of the commer ts4 to understand this. I am sure most stories like the ts4 never even see the light of day. Often old, entrenched executives, engineers, and CEOs simply bury things that might reveal their incompetence, or lack of vision, or the fact they are stuck in a certain era of technology and are threatened by change to what they are familiar with..."

It also takes time to make engine changes in the automotive industry, no one has a magic wand they can wave to insantly change anything.

There are billion dollar car/engine companies around the world right now desperately developing (and falling behind) for Euro 5/6, if a "cheaper and lighter" DFI 2 stroke worked they would be onto it quicker than you could blink. And it's not just the engine - cooling system, chassis, transmission, brakes, suspension ie; the whole bloody car is cheaper and more profitable with a lighter engine.

If it worked most would already have minor base models running around.

http://www.mynrma.com.au/motoring/reviews/...al-ecosport.htm

Mariner, the Goliath 900 was also a two-stroke, but was equipped with a carburettor. Only the 700 had the optional DI system, if I recall correctly. By the late '50s, an 1100 4-stroke h.o. four replaced the 2-strokes. As far as I know, "Die Kraftfahrzeuge, und ihre Instandhandlung" by Ing. Trzebiatowsky was never translated into English, which is a shame, because it is also an invaluable source of information on hot-bulb engines (as exaplified by the Lanz Bulldog farm tractor), among other things.

Just what I was thinking. End to end scavenging, direct fuel injection two stroke.

It is interesting that the engine evolved from a Diesel engine to a petrol "sprint" engine, which wasn't expected to have very good fuel economy. It turned out that the fuel economy was very good at full throttle, but not so good at part throttle. RR considered the Crecy to be a full throttle engine, like early gas turbines.

The Crecy was originally designed without a throttle - engine speed and power was to be controlled by the amount of fuel being injected. But RR could not get the system to work properly - a limitation of the control technology at the time?

The head of the Crecy was also shaped for a stratified charge.

The main problem with the Crecy was that it melted pistons. Piston cooling was inadequate, involving oil pumped up through the centre of the rods. A fix would have seen external oil jets as in other RR aero engines and a few of today's engine.

Well, cross-thread alert there, I think!

Volvo (the truck maker) have stated that they spend something like half of their R&D budget on passing exhaust emission legislation, clearly, if there was a cheap option availible they would have taken it.

I think the poor efficiency (and power output) at anything other than full throttle conditions was as a result of the fixed position of the ports.
This problem carries over into opposed piston blow scavenge two strokes as featured on another thread.
It is the main thing that prevents wide spread use along with the piston rings passing over the ports causing excess oil use and wear.
I think the idea I am looking into will cure both these problems.
Of course it will need a lot of investigation (as usual) and it may throw up other problems, so to early to say much or to be too optimistic.

I believe this issue is solved by the "reverse-uniflow" engine design where the exhaust ports are at bdc in the liner, and intake is in the head through poppet valves. If one utilizes an "infinitely variable" valvetrain design for the intake valves and incorporates a long stroke, this design avoids the problems you mention, and adds a great deal of variablity to what the engine can do. It could even operate at different compression ratios on the fly without introducing quench problems...

I'm quite ignorant on the subject, can you lubricate a two stroke without burning oil? If not, doesn't it pollute a lot?

Yes you can.



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It may have also been due to the compressor, which was single stage single speed (IIRC) and was used to scavenge the exhaust before the fuel was injected. A relatively high percentage of compressed air was pumped straight out the exhaust.