An engine design they think is new
An engine design they think is new
(OP)
https://www.youtube.com/watch?v=Ov73-okhkG0
I wonder if Fairbanks Morse knows about this? They still make the OP engines, and have been using this architecture for I don't know how many years. And why would they say the idea was abandoned in the 40's? The hype for some of these supposed great IC engine ideas is just getting old.
I wonder if Fairbanks Morse knows about this? They still make the OP engines, and have been using this architecture for I don't know how many years. And why would they say the idea was abandoned in the 40's? The hype for some of these supposed great IC engine ideas is just getting old.





RE: An engine design they think is new
Since the surfaces of the cylinders or the pistons can never truly be perfect, wouldn't each piston have different frictional characteristics exerted on it? Since the opposing force on each piston is another piston (a dynamic element)and the two crankshafts aren't connected, wouldn't one side receive more power than the other from combustion outside of theoretical models?
Or am I totally wrong about this? I also didn't delve too much into their design though; do they have a way to overcome this aspect?
Andrew H.
www.mototribology.com
RE: An engine design they think is new
RE: An engine design they think is new
Here is an OP diesel engine effort I worked on almost a decade prior to the start of Achates' project: https://docs.google.com/viewer?url=patentimages.st... The patent drawings are taken from my layout model of a single cylinder test rig. I left the company after finishing preliminary design of the test rig in late '96, so they didn't list me as an inventor on the patent filed in '98. The test rig was built and run on the dyno, but I don't know how much more work was done before the project was terminated.
RE: An engine design they think is new
Andrew H.
www.mototribology.com
RE: An engine design they think is new
Not sure anyone is under the impression that design is new, its definitely a turd regardless.
RE: An engine design they think is new
Since they are using transfer ports I want to see how they prevent oil leakage into the exhaust pipe.
B.E.
You are judged not by what you know, but by what you can do.
RE: An engine design they think is new
RE: An engine design they think is new
No. The pistons sharing a cylinder are exposed to the same conditions at the same time- there is no difference in force applied to them.
RE: An engine design they think is new
RE: An engine design they think is new
Steve
RE: An engine design they think is new
It's not an auto engine, it's a multi-fuel *tank* engine! The 6TD variant is the latest in a long series of tank engines dating back to the 5TDF engine used in the T-64 tank (deployed in 1967). Of course most of these opposed piston engines trace their heritage to the Junkers Jumo 205 which entered service in 1932 (https://en.wikipedia.org/wiki/Junkers_Jumo_205). Over 900 of the Jumo engines in one configuration or another were used in German warbirds. The Wikipedia article linked above also mentions a few other notable opposed piston engines: The Commer TS3, Leyland Motors L60 tank engine, Rolls-Royce K60 engine, and the Fairbanks Morse 38 8 1/8 (in addition to the 5TDF and 6TD already discussed). That's an awful lot of engine designers who view this architecture as more than a research exercise.
RE: An engine design they think is new
Reason: hidden downsides that the advocates never tell you about.
In a diesel engine, squirting fuel in from the edge of the cylinder probably doesn't give as good in-cylinder fuel and air distribution as squirting fuel in from the middle into a central bowl in the piston, and in this day and age, if you can't get the emissions right, the whole deal is a non-starter. Opposed piston means you can't use a central injector with a bowl in the piston.
All piston-ported engines have issues with lube oil escaping via the ports. That's bad for emissions. Again, in this day and age, if you can't get the emissions right, the whole deal is a non-starter. Detroit Diesel built piston-ported two-strokes for on-road applications for 50 years, and they gave up and went four-stroke when faced with 1990s-era emission standards, and those standards are a lot tougher today.
RE: An engine design they think is new
All good points. In my engine, I have no spark plug or fuel injector, so I've sidestepped that problem. I have provisions for lubricating around the ports and preventing oil from entering the exhaust, but they are unproven and still worry me.
Rod
RE: An engine design they think is new
I don't believe injection from the side(s) is the dealbreaker - there are many efficiency advantages to OP architecture that compensate to varying extents.
je suis charlie
RE: An engine design they think is new
A DOHC 4-valve cylinder head is not particularly compact, in any case ...
The Wankel rotary made its name for being compact, and Mazda designed cars around it, and yet, you can buy kits to stuff a Chevrolet small block V8 under the hood of those cars and still be able to close the stock hood on it, which is great for when the Wankel kicks the bucket, which it will ...
RE: An engine design they think is new
RE: An engine design they think is new
http://www.opposedpistonengines.com/
RE: An engine design they think is new
The best point bsfc figure they achieved on their 4.9 litre 3 cylinder engine was around 194 g/kwh. They were predicting and touting in the 180s before that. Neither are remarkable. Also- consider that- a 4.9 litre 3 cyl is a massive cylinder and they were continually comparing it to the Ford Scorpion 6.7 litre engine and making ludicrous assumptions for after treatment efficiency. Similarly touting the benefits of a longer stroke engine while ignoring the associated knock on effects to friction isn't prudent. When you put it in this context its not remarkable at all. A good quality 4 cylinder 4 liter diesel will achieve about the same best point bsfc with similar common rail hardware. SOme of the bigger cylinder HD applications may get in the low 180s.
I also find it amusing when they tout the use of no valvetrain - hence claiming less friction- totally ignoring the fact that the valvetrain has been replaced by a whole crankshaft and set of pistons. Folks are seeing through these lies now. Don't get me wrong, I do see the potential of a two stroke diesel, but not one run by a cult. The other inherent hurdle for a uniflow scavenged 2 stroke is getting the after treatment lit off quickly- it will tend to fun a lot cooler than a conventional 4 stroke. You see this on the old Detroit diesels also. This is due to the bypassed air.
To the original poster- Achates bought the General Atomic OP engine and hardware. They also did consultancy work for Fairbanks Morse but ended up causing a lot of carnage there. TARDEC hasn't been impressed with them either. Lets see how long they last....
www.auto-scape.com
Sideways To Victory!
RE: An engine design they think is new
This breakthrough technology merry go round is predictable and monotonous. It is invariably a case of a crackpot or a sly, albeit sane, person or group pulling the wool over the eyes of the greedy and gullible.
My prediction is, the next big breakthrough (not evolutionary step) in IC engines, if it ever comes, will NOT be presaged by a drawn out venture capital campaign, but will appear suddenly from a world class OEM, or possibly from a brilliant, capable, well-rounded, and internally funded not to mention secretive private party or consortium.
"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz
RE: An engine design they think is new
I agree, Ive often seen ego-centric 'larger than life' characters starting up these Start up companies who schmooze the VC companies and bowl them over. Unfortunately , good engineers are more often than not more data driven, balanced, transparent with less emphasis on Ego....
It would need to be an OEM with a long term view and a horizon much longer than the next quarter!
www.auto-scape.com
Sideways To Victory!
RE: An engine design they think is new
"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz
RE: An engine design they think is new
http://www.foxnews.com/auto/2017/10/04/cummins-dev...
RE: An engine design they think is new
je suis charlie
RE: An engine design they think is new
RE: An engine design they think is new
... but not very often.
RE: An engine design they think is new
RE: An engine design they think is new
It also has an inherent transient response advantage- if that was a priority for big trucks.
I don't see this solution sweeping the nation of our line haul applications.
I could be wrong- whereby high BHP/litre becomes a priority in trucks over high efficiency and durability :D lol
www.auto-scape.com
Sideways To Victory!
RE: An engine design they think is new
reporting 50% efficiency. And in the reciprocating world only 2 strokes do that as far as I know. I wonder how many copy cats like the one this thread is about that will be made?
RE: An engine design they think is new
Because the architecture is well established prior art, Achates's patents are founded on design details rather than the concept.
RE: An engine design they think is new
https://www.youtube.com/watch?v=D3bj47TAYiU
Not very practical for automobiles, but an interesting engine to see in action.
RE: An engine design they think is new
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: An engine design they think is new
ptfnasty.com
... some links lead to audio recordings of Deltic-powered locomotives.
The sound is haunting.
No way would they meet modern emissions requirements.
Mike Halloran
Pembroke Pines, FL, USA
RE: An engine design they think is new
Theses were valveless engines with one piston per cylinder.
Both the intake and the exhaust were ported.
Bill
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"Why not the best?"
Jimmy Carter