The Two-Stroke Engine, Reconsidered

As one person asked in the replies to the Technology Review forum: What is the method for lubrication?

Lubrication in novel new engine designs is a subject that tends to be left for the engineers to solve later after the investers have fronted a pile of money. Usually gets addressed after the first few attempts to keep a single cylinder engine running for more than a few minutes on the test stand.

Been there, done that while a lubrication issue that could have been dealt with at the concept stage took down a well funded multimillion dollar engine development program.

BTW, it was a 2 stroke engine design.

Ed Weldon

My purpose in asking about the method for lubrication stems from the fact that In my opinion, however humble, the "demise" of the two-stroke is connected directly in part, to the method used for lubrication. Another unusual detail (shown in the cut-away) is what appears to me to be side loaded connecting rods, with the wrist (or gudgeon) pins requiring substantial support and slots to travel in.

...a turbocharged "direct-injected" two-stroke would be both (a) practical and (b) viable, *if* someone would just "DO IT!"

Looks quite complicated with a lot of additional moving parts. It seems almost all the pistons would have dual push rods for one thing.

One nice thing about the EVs is they can become more simple rather than more complex.

I would like the OP to get in touch with me. EcoMotors are going to very upset for a while about what I would change but it would enhance lubrication as well as some other issues they are not telling us about.

If they ever throw that test engine out I want it. It would save me a lot of third party involvement and alterations could be done in no time at all. Sunday morning here, make my day, Ky.

Done before with the Commer "Knocker" diesel motor, except they're using a electric turbo instead of a Rootes style blower.

Also in the comments after the article someone mentioned Fairbanks Morse opposing piston motors.

The question one has to ask, (and I do know most of the answers to this one) why were these motors not more "successful"?

Followed by, Why do you think you could do it better?

Here is an interesting site found Googling "new two stroke technology". (again no mention of lubrication).

http://www.allpar.com/neon/stroke.html

Evidently it is too efficient.

The deltic engine also seems to have some promise. (3 crankshafts, 3 cylinders, 6 pistons, in opposed pairs arranged in a triangular layout.

I've only known it used in some large diesels.

2 stroke diesels can be made efficient by turbocharging and using excess air to scavenge exhaust gases out of the cylinder. Presumably so can a direct injection engine.

The makers here say they have basically made a number of small improvements in various areas to achieve their overall efficiency gain.

NOx could probably be overcome by careful use of stratified charge injection. I think Auto union pioneered this in passenger vehicles long ago (sometime in the 1980's?). Their engine could be run on any combustible concoction. A test used sump oil and diesel, even though it was spark ignited!

Given that the EcoMotor design appears to dispense with camshafts, heads, push rods, etc., isn't it actually a LESS complicated design with fewer moving parts?

Also, if it's twice as efficient as current EPA-approved engines, shouldn't its emissions standards take that into account. That is, if it takes half the fuel, shouldn't it be acceptable to be up to twice as dirty?

Regarding emissions and just wondering out loud... What is the relatively density of the unburned fuel compared to the other elements in the exhaust gas? If so, could a strong vortical flow be used to selectively tap that fraction? If so, given the intended use of a turbo anyway, is there some way to use the turbo or a paired turbo to spin the exhaust gases and meaningfully recapture unburned fuel for reintroduction into the combustion cycle?

Probably, the optimum application in automotive use is to find that RPM that yields the best combined efficiency/emissions performance and run it at that RPM in a hybrid config.

Given the power density and the 2 strokes, it will likely generate mucho heat and require robust heat exchange. Can all that heat be put to some novel use?

I'm not an engineer, but I like to ponder engineering issues...