What are your opinions? Could this new engine eventually replace the diesel engine in the small pickups? It's got great fuel economy.

Achates Opposed-Piston Engine Promises 37 mpg For Full-Size Pickups

 

Replace, I doubt it.

How many here bought their truck because, Cummins?

It would be nice to have a 2 Stroke diesel again

 

Well, the physics are fundamentally sound, after all, the fuel economy record Junkers set back in 1936 has not been challenged, and to make a diesel aircraft engine that even survived a 6000 mile flight means it isn't structurally unsound, add in the technology available today and the sheer determination to get it to market, and I think it has a much better than even odds of turning the marketplace on its head.

They have been working hard on this since 2001, and according to the CEO they now have engine development contracts in place with at least 9 companies ( Including Cummins !!!!!!!!!!! )

Yep, I would buy one in a heartbeat, my only reservation would be that if it were built in a vertical piston configuration, I would want to know how the upper oil scavenging is being accomplished.

 

I don't know a great deal about them but it's certainly not anything new in the diesel world. Fairbanks Morse has been building opposing cylinder 2 stroke diesels for somewhere near 100 years.

 

The apposing cylinder concept has been around for some time. Nothing new.....but not something proven practical so far.

And watching the video I really dont see the gains either. Yes there's no "valve train".....but there are TWO huge cranks where the normal everyday engine has one. Not sure why another big heavy crank is better than a light weight cam and some valves.

And the port design are nothing new either as this is the premises behind the original 2-stroke engines. Which.....require the function of an additional forced induction super charger to use under low engine load conditions otherwise they're totally inefficient.

And I really liked the "oil consumption on par with other four stroke engine" disclaimer. That tells me this is an issue which will more than likely be the Achilles heal as people find themselves dumping more and more oil in these engines over time.

I think its a gimmick.....

 

Be careful poo-pooing it...............

I took a couple hours researching it and all the info out there so far, and I sure as heck can't find anything gimmicky about it......
The Defense Department and Cummins have them under development contracts for a reason.......

 

I guess I shouldn't have been so harsh as to call it a "gimmick" as thats not fair to the lengthy history behind this engine.

But my point about practicality was merely to address that the consumer world doesn't typically accept major changes very quickly. Meaning, even though people like the latest and greatest, they still would rather have something they recognize over that of being the guinea pig for something completely different. Rotary engines couldnt get a strong hold on the auto market and electric cars are still fighting for their space. Auto manufactures want to build something new and different.....but above all, they want to build something people will buy. Just my opinion.....but definitely doesn't make it right.

 

No, you are right, Rotaries had major technical issues that just weren't easily and cheaply solved, and Electric, IF they can ever solve the energy density and refill time issues, will very quickly take over ( fat chance, we are talking orders of magnitude improvements necessary ).

The average person will not even know there are 2 crankshafts and no valvetrain, what they will know is a F150 gets almost 40 MPG without giving anything up, or their Dodge Charger now gets 65 MPG without giving anything up...... They pop the hood, it all looks the same to them.

I sure as heck hope someday fairly soon to be able to buy a Dodge 1/2 ton with a Cummins/Achates diesel.............

 

If you think about it, it's almost the same tech the Detroit 71 series used ... and that was a damned fine engine once you got it wound up. If I remember, there was a 6 cylinder pancake engine, the 6L-71, that Detroit used for buses and the like, and maybe this is where they got the idea.

The biggest concern would be emissions. Detroit stopped producing it in the mid-90's but because it was dependable (as long as it wasn't leaking) there were a lot of them still in service. If they can get the emissions under control it should be a decent little engine.

The only other concern would be how fast this 2 stroke is gonna be spinning, and if it needs to be wound tight like the 6V-71 needed to be run.



-Kris

 

On the subject of different engines, just happened to come across this a few minutes ago;

https://youtu.be/jdW1t8r8qYc

 

The one thing that stood out to me is that with the opposed piston configuration,the intake and exhaust ports are at opposite ends of the cylinder which gives you 2 things over a single piston 2 cycle engine.
1. The ports are near the end of the power stroke, thus making most of the stroke usable for power transfer from expanding gasses to the pistons.
2. The air and exhaust flow through the ports and cylinder is pretty straight through and mostly while the pistons are near stationary at the end of the stroke. I can see that as much cleaner than a cross flow 2-stroke.

The only downer I see is lubricating the seal that crosses the ports. Pretty much the same problem as the Wankel engine has.

I like it. I think it'll go places. I suspect that the military interest in it is in power density, multi fuel capability, and reliability.