Slightly off topic. New Diesel design

I saw this and thought some others would enjoy seeing it too.  Having spent many hours behind a Detroit diesel and knowing the negatives of two stroke diesel engines I don't see how this thing is going to hold together or how they will be able to keep it oiled properly but it sure enough is interesting and the US Army thinks enough of the idea to pay for a prototype.  We'll see how it turns out.

Kinda similar to this http://en.wikipedia.org/wiki/Opposed-piston_engine

Lot of smoke an mirrors at this point.  Subaru and several airplane engines are opposed.  The only difference in  their system is they add another piston.  Big difference I know but it adds moving parts.  Moving parts mean friction and more potential problems.  If I were to see a new engine design I'd like to see one that runs on vegetable oil straight from the factory.  Or see one that is designed to run on ethanol instead of these gas engines converted to accept ethanol.  But, IMO, eventually we'll all be driving electric vehicles with fuel cells added for range.  Current engine designs have been tested and developed for 100 years.  In a 50 years, when new engine designs will be mature, will we have any oil left of will it be price competitive?

I just don't see how the thing is going to stay together with two external connecting rods with no way to splash or spray oil the wrist pin except by pumping the oil through the connecting rod (I'm assuming that is what they intend to do)   Also, assembly of those rods is going to be critical because they both have to be set up exactly the same to keep the piston in line.  Add to that the fact that those connecting rods are running in tension instead of compression like typical rods.  The design engineer has had a long

I know that there have been ship engines built that were horizontal opposed piston design but those were huge, slow moving engines and weight is not an issue with them.

The German Junkers Jumo 205 Aircraft used an opposed-piston Diesel engine.  Two crankshafts, one at the top and one at the bottom, geared together.  Worked pretty well...also used ports like this one does.

Don,t see mutch advantage over  what we already have. Might be a way to get high compresson in a two stroke engine with shorter stroke. Off subject: I once saw something  about an engine that worked on a wobbleing plate  with cyl on each end . Kind of like a hydl pump. Have anybody learned any thing on this.

From what I could gather watching the video, the efficiency gains come from balance, thus less weight in motion within the engine in addition to less total vehicle weight; two cycle vs. four cycle (2x as many power strokes); shorter piston travel, thus less drag and also less friction heat loss.  Those would be the big ones.  He also mentions being able to shut down portions of the engine during lower power demand and not loosing the balanced characteristics of the engine.

I assume this engine will need to the turbo charged.  Reason: fuel charge will have less time to charge the cylinder.  Also lubrication of wrist pins and rods is a real issue.  I have seen the wobble plate design and it appears more promising.  Again the emissions are a issue.

Fairbanks-Morse built opposed piston engines beginning in the 30s that were used in WW2 ships and submarines. They were tall. Many a surplus FM ended up in small town power plants where they still are used for backup when the lines go down. FM also built a line of diesel locomotives with those engines. Two cranks, two pistons per cylinder. Gets you the compression needed for diesel with half the piston speed, so they can be long lived. But I wonder about how light weight they would be for an aircraft engine.

I visited a small town power plant where the operators were wanting to sue an oil vender because the rod bearings in their FM engine were only getting 80,000 hours life instead of twice that that they were accustomed to.

But then German WW2 engineering wasn't always about performance. Sometimes it was seriously over designed. I took engineering mechanics from one of those German engineers. He told about freight aircraft with a corrugated skin with a times 10 safety factor after they cut a hole in the side of the fuselage top to bottom and wide enough for loading a grand piano. Flew so slow, that allied aircraft batteries tended to miss by leading it too much. With a non technical dictator, any way to spend money was encouraged so long as it promised to make good use of fuel that they ran low on and they had to invent ways to make fuel without oil wells. Same thing for tires. There was much innovation, but likely much corruption and misdirected experimentation.

Gerald J.

 I wonder with the different length of rods (inner and outter) if rod stretch will make the balance change?

TexasAllis, 

Two other things I saw since the pistons move half as much the speed of the crank is doubled increasing the power density.  The other was in the valving and if I understand the concept there is no or very little mixing of fresh air/fuel with exaust gasses like you have in a tradtional two stroke.

Edited by TexasAllis - 23 Feb 2011 at 12:50pm

I agree with a previous post, this is a take on the Jumo and the Fairbanks Morse engines of the 40's to series of the 70's, not new technology but a spin on functional and adaptable technology.

Fairbanks still manufactures parts for the opposed piston engines of the WWII marine and late 50's rail type engines, a few are still in service as standby generation engines for power stations.