advanced angine - suitable for marine use ?

[sarabande]

advanced engine - suitable for marine use ?

http://www.engineeringtv.com/video/Opposed-Piston-Opposed-Cylinder


Looks very clever. Multi-fuel; highly efficient about 40 %; selectable number of cylinders.

Any views ?

 

[davidej]

Opposed piston diesels have been around for years but with two crankshafts- one at either side of engine.

this concept is new to me and seems very clever but will mean a very wide engine

 

[earlybird]

Haven't single crank-shaft, opposed piston marine engines been around for nearly100 years,
made by Doxford.

 

[ALPHORA]

The Napier Deltic engine seems to use the same idea for port timing and has been in use for many years. Nice cut away engine at the York Railway museum if you are into that sort of thing

 

[Bilgediver]

http://www.engineeringtv.com/video/Opposed-Piston-Opposed-Cylinder


Looks very clever. Multi-fuel; highly efficient about 40 %; selectable number of cylinders.

Any views ?

Oh well someone had to do it.....ANy one who was at sea more than a few weeks ago will recognise the similarity with the Doxford marine engine.

Yes here it is two opposed cylinders instead of cylinders in line however three cranks and con rods per cylinder. It will be interesting to see and hear the prototype run however the biggest problem will be emissions in this modern day world as timing by piston controlled ports is not exactly the must user friendly system for effecting variable timing. Mind you the MK 1 Doxford had a common rail fuel system and the mechanically controlled injector could be adjusted both in regard to opening timing and closing timing. Something not easily achieved again until recently .

 

[trapezeartist]

If the claim proves to be true, the key point is the 40% efficiency. That is enough to make it worthwhile.

Like so many two stroke engines (petrol and diesel), it seems that the efforts to overcome the inherent problems of two stroke result in ever-increasing complexity. Thus negating one of the greatest advantages of a two stroke.

The wide, low, short box that the engine appears to fall into is both advantage and disadvantage. It looks like it should package really well into a commercial vehicle. It may also work in a mobo, but it is too wide for a yacht. Certainly any boat would have to be designed from the keel up to package the OPOC engine: it won't be a retrofit.

 

[sarabande]

what if you turn it through 90degrees so the long axis runs fore and aft ?


OK, it then needs a right angle gearbox...

 

[Wunja]

what if you turn it through 90degrees so the long axis runs fore and aft ?


OK, it then needs a right angle gearbox...

... or paddle wheels.

 

[CharlesSwallow]

"Boxer" engine

I always thought that such an engine is more appropriate to the term "Boxer" than that which currently holds the title since it's action is really like that of a boxer punching his gloves together before a bout.

However, leaving aside the semantics, I don't know how durable such a beastie would be. Those external con-rods look awfully vulnerable and difficult to keep stiff, lubricated and cooled. Dimensionally too, it is hardly ideal as a yacht motor.

The little internal combustion engines originally made to power torpedoes had a huge power to weight ratio but they were hardly durable - they didn't HAVE to be, after all as they were only required to make one short and sensational journey!

Chas

 

[Plevier]

If the claim proves to be true, the key point is the 40% efficiency. That is enough to make it worthwhile.

This claim surprises me. Experts on engine development that I work with at a university tell me that a - possibly the - major source of losses in rotary crank engines is piston ring to cylinder drag. That's why development efforts on hybrid vehicle range extender engines concentrate on 2 cylinder types (single cylinder being unacceptably rough). Doubling the number of pistons doesn't seem a good idea for efficiency in the light of that.

Reading the blurb below the video it seems the primary motivation behind the design is power density not fuel efficiency. That makes more sense on a DARPA development contract. Since when did the military worry about fuel efficiency?

 

[dylanwinter]

Oi

This claim surprises me. Experts on engine development that I work with at a university tell me that a - possibly the - major source of losses in rotary crank engines is piston ring to cylinder drag. That's why development efforts on hybrid vehicle range extender engines concentrate on 2 cylinder types (single cylinder being unacceptably rough).

Oi - unnaceptable the beast in the slug - volvo MD1

unnacceptably rough! The beast will be crying in the bilges

I accept it

D

 

[30boat]

The little internal combustion engines originally made to power torpedoes had a huge power to weight ratio but they were hardly durable - they didn't HAVE to be, after all as they were only required to make one short and sensational journey!

Chas

I thought torpedoes were propelled by compressed air motors?

 

[tinkicker0]

Just another reconfiguration of the Roots TS3 and the BMW diesel aero engine before that.

 

[Norman_E]

OK for the military in the US but over here 'Elfin Safety will have a fit when they see the exposed moving parts!

Given the service conditions of militaty vehicles I would think that the whole thing would have to be boxed in to avoid sand and grit getting into the bearings of the exposed parts.

I too thought that torpedos had compressed air engines.

 

[rotrax]

OK for the military in the US but over here 'Elfin Safety will have a fit when they see the exposed moving parts!

Given the service conditions of militaty vehicles I would think that the whole thing would have to be boxed in to avoid sand and grit getting into the bearings of the exposed parts.

I too thought that torpedos had compressed air engines.

Hi, Torpedoes have compressed GAS engines,not compressed air engines.Several submarine accidents have occurred when such an engine has started in the vessel,mostly fatal.

 

[DownWest]

Wasn't the Kursk sunk by a Hydrogen Peroxide torpedo mishap?
These engines probably of more interest to MOBOs for economy reasons and low CofG. Yachtys are less concerned as fuel is not such a big factor.
Probably not cheap , but I like the electric assist turbo, presumable to get it started.

I remember a big buzz about ceramic engines, esp of interest to the military as they need less ( vunerable)radiator cooling. Any one heard something recently?

 

[CharlesSwallow]

I thought torpedoes were propelled by compressed air motors?

There have been all sorts or motors used over the years, except gasoline.

Chas

 

[Plevier]

Oi - unnaceptable the beast in the slug - volvo MD1

unnacceptably rough! The beast will be crying in the bilges

I accept it

D

Oooh sorry slug!

 

[grumpygit]

Just another reconfiguration of the Roots TS3 and the BMW diesel aero engine before that.

You are correct, Commer used the TS3 (TS4 was mothballed) for about 15 years in their heavy commercials. It all seems a touch of smoke and mirrors to me or akin to reinventing the wheel.......It's strange that Commer was under the Rootes flag which then went to Chrysler who must still hold patents and they are an American company. What goes round comes round I suppose.

Unless they do some neat tricks with the fuel management, emmissions and noise control, I would not entertain two stroke diesel in anything that I would own. They where smelly, smokey and very noisy and from what I remember not fuel efficent at all.


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[SHUG]

Interesting engine but flat format doesn't lend itself for "low" installation in a boat.
An engine that I thought was perfect for the boat was the Steyr Puch engine which was widely used by the militart (Haflinger?)
I can't get a diagram but it had no cylinder gasket and was oil cooled= no corrosion.
The cylinder head and bores were all as one casting which bolted onto the crankcase.