[evilgenius]

I was just reading about this engine on the Forbes site, http://www.forbes.com/sites/billvisnic/2015/06/13/should-tesla-worry-about-achates-reboot-of-1930s-technology/. It's an opposed piston technology. This means that the pistons meet each other in the cylinder head. Granted, it's a two stroke, and it has two crank shafts, but this doesn't have to be the final word on motors like this one. I'm pretty sure, as in I've already figured out how it can be done but can't afford to build one, that it can be done with one crank and as a four stroke.

The levering is more complicated than most folks are comfortable with when you shed the second crank. The thing to keep in mind, though, that makes it possible to change the Achates design up, is that you don't need as much leverage to make the compression stroke happen as you want to provide for the power stroke to make things go.

Think of it like this, when cars race around a track all day in one direction then there isn't very much call for them to turn the other way. Building a car to do this uses something called weight jacking. Weight jacking leans a race car into a turn ahead of time. It can be done since there will be no call for the car to have to unweight in order to turn the other way. This same concept can be applied in order to lever the power such that more of it is used to make drive power, and less of it is used to compress the pistons together.

Anyway, I bring this up because I think the basic design of the Achates engine seems like it would be interesting to people here. Obviously, I am interested in this for my own reasons, but I'm not asking you to follow my way. Maybe the way Achates is going is the right way. They seem to have a functioning prototype, at least. And it is very interesting how a mix of IC and electric was suggested in the article as a better solution going forward than one over the other.

[ennui2]

There are a few technologies that can and probably will wring some extra efficiency out of ICE vehicles. The move to higher mileage standards will see the kitchen-sink thrown at the problem. We're at the point of diminishing returns, though, so I'm not expecting to see some huge breakthrough.

[jjhman]

I'm pretty convinced that if battery technology or, more likely, super-capacitor tech moves very far in the next couple of years it will be the end of the IC era. The combination of overall efficiency, climate legislation, performance characteristics and noise level should render IC powered vehicles to the historical junkheap.

[Subjectivist]

The best thing with these opposing cylinder designs is their valve system. An old fashion ICE wastes a tremendous portion of its power compressing and releasing valve springs. By using two Pistons you can have one control the intake air and the other control exhaust gasses. This is much cleaner and more efficient than the turbo diesel power stroke system that uses a cylinder opened exhaust valve and a spring operated intake valve.

[StarvingLion]

Wow, I'm so excited. In the Finance Economy of 10x more people, 1/10th the living space 10x more corruption, I have to ask the question,

How is this possibly relevant?

[Scrub Puller]

Yair . . .

I can't see any return to the archaic architecture of the Commer Knocker, Napier Deltic et al of my youth.

The concept works, but the biggest advantage is not so much the combustion process but the fact the power is delivered by way of multiple crankshafts (in the Napier and its variants) and via multiple levers and linkages in the Rootes Knocker and it's clones.

This results on very under stressed components with extreme service life.

I believe the next incremental improvement of the ICE will be compound turbo charging whereby the recovery of power from the exhaust gases is augmented by a second exhaust turbine, geared to the transmission

This is very old technology, first trialled on aviation engines. Perkins played around with it for awhile but it proved too complex. The concept has resurfaced in the present Formula One engines and is offered on certain European heavy diesels in automotive and agricultural applications.

Some manufacturers claim in excess of fifty horsepower back into the power train.

Cheers.

[Keith_McClary]

From the Forbes comments:

Robert Miller
...
Immediately I see two cranks. A Crank is not a trivial component – it is very heavy. And that is not a trivial mechanical assemblage to combine two cranks into one power output.

And now you have an engine block that is nearly doubled in size. And what’s worse is that what has doubled in size is the massive and complex part of the block (crankcase assembly) rather than the simple lighter part – the cylinders.

And you say that it eliminates the valves and valve train? But that is replaced by a far more massive and complex mechanical assembly of TWO cranks. And further, to be fair, in an apples to apples comparison, we should be comparing two-stroke to two-stroke. And a ordinary two stroke doesn’t have a valve train, so it’s somewhat disingenuous to claim it eliminates a valve train when you can do that with an ordinary two-stroke. For that matter, the advantages of a two-stroke compared to a 4-stroke in terms of simplicity and “volumetric” efficiency (power output for engine package size and weight) so it’s unfair to claim that as an advantage of the Achates when that is just a basic nature of two-strokes in general. The downsides are fuel inefficiency and emissions.

So what it really comes down to fundamentally, is how does it solve the fuel economy and emissions problems of two strokes? The dual opposed pistons is just a red herring – smoke and mirrors. I mean if it has a real solution for those problems, then I’m all ears. But then for that matter, why couldn’t that then be adapted to a more conventional two-stroke and save the mass and complexity of two cranks?

How do they connect the two cranks? Chain?

[evilgenius]

Wow, I'm so excited. In the Finance Economy of 10x more people, 1/10th the living space 10x more corruption, I have to ask the question,

How is this possibly relevant?

Perhaps the most relevant thing about it is the possibility that it can greatly increase fuel economy. If it can do that, then by how much? If you can get enough fuel economy improvement it might be possible to see ethanol in a new light. I've always thought that the real question with ethanol is not will it work as an alternative fuel, but how many miles per gallon do you need to get with an engine running it to consider it as a fuel, without taking away from food? I don't know what that figure is, nor whether an opposing piston engine can reach it. The article, however, does allow us to speculate. And we can speculate upon what any further advancements to the concept might accomplish as well.

Further, looking at fuel powered engines is not anachronistic in light of other technologies, like electric. The reason, of course, is that many of us need our cars to produce heat as well as power. In cold climates where is that heat going to come from?