Eco Motors - OPOC engine

[TransformX]

http://www.autoblog.com/2009/11/30/autoline-on-autoblog-with-john-mcelroy

[Brian Ellis]

Sounds like a development of the Oechelhaeuser and Junkers motor patented in 1892! Worked on exactly the same principle!

[MultimediaMan]

Opposed piston engines are nothing new - they are common in certain types of marine engines; a two stroke diesel was actually used in aircraft for a brief period of time. Crankshafts with couplings are also nothing new (Just look at any large diesel-electric locomotive).

The chief advantage of opposed piston engines are smooth running (they are by default counter-balanced), and strength (the pistons divide the BMEP, allowing connecting rods, wristpins and crankpins to be smaller - the biggest advantage in this area is rod angularity is reduced, which lowers wear on cylinders). The opposed piston engine is essentially a very long stroke engine, but with two crankshafts dividing the stroke. As was mentioned in the article, the engines are fairly mechanically complex, and require forced induction to get the emissions down on them. They might be using something fancy like using some amount of DeSaxe offset to further reduce rod angularity, and provide assymetrical port timing.

ETA: they've put REALLY long rods on the "hot" side of the engine, this will dramatically slow piston acceleration, which is how they are getting assymetric timing apart from the intake ports (The intake ports are controlled by the inboard piston). They have to have some sort of oil control ring on the pistons - probably below the port openings at TDC.

[VJ]

Am I the only one who thinks it is sad that specifically (mainstream car-)engine technology seems to be (or has been) focussed at just one technique, the 4-stroke engine? In the past, and especially during the early days of the combustion engine, there were so many different designs. And a lot of them were used, even if it sounded mad (using a radial engine on aircraft for instance is asking for problems: it acts as one big gyroscope, screwing up the controls).
Now, it looks like people/companies are open to other designes though... (finally)

[MultimediaMan]

Many times, the engineers who came up with certain engine designs were doing so for reasons beyond power production: The Rotary Engine was designed to solve both balance and cooling/pre-ignition/detonation problems faced by early gasoline engines (Tetraethyl lead wasn't used until the 1920's, which allowed higher compression ratios). Advances in metallurgy and a better understanding of fluid dynamics in 1930's saw the rise of overhead valve engines for high performance engines. There hasn't been much innovation in ICE development since the Gas Turbine, but there were literally Thousands of different piston driven designs tried from the 1890's until the 1950's.

The Modern low-maintenance ICE came into being in the late 1950's: Aluminum Pistons, long life compression rings, effective oil control rings, hardened Valve Seats, fuel injection, and electronic ignition all made the ICE much more efficient while at the same time reducing the need for regular maintenance dramatically. The last major piece of the (physical) puzzle came into being in the 1960's with the perfection of Multi-Grade motor oils, which made changing your oil because of the seasons a thing of the past.

The four stroke engine has lived on so long because of it's relative simplicity, but looking at a modern ICE you could hardly believe it.

[Brian Ellis]

MMM
Cannot agree with you that development of the ICE stopped in the 1960s. Some of the things that became mainstream since then:
Electronic fuel injection, replacing carburettors
Multi-spark ignition
Electronic valve control
Four valves/cyl
On-demand cooling
Variable number of active cyls
Lead-free fuel
Catalytic pots with lambda control
Atkinson-style conn rods
Die-cast cylinder blocks
Better crankshaft alloys and balancing
Better white metal alloy coatings for bearings and big ends
etc., etc., etc.

[MultimediaMan]

With the exception of advanced composite coatings (Boron Nitride, Titanium Nitride) or advanced metal treatments (Cryogenically Stabilized Steel), everything you mentioned was invented or conceptualized prior to 1950... quite a few engines which used some of those features were research or prototype engines.

Multi-Valve Cylinders were done in late 1919 by Harley Davidson. Another Small Motocycle outfit (Eli Wallace, I think) from the same era made an overhead 6 valve single cylinder engine for his motorcycle.

Multi-Spark ignition has been around since the 1930's, when Dual Magneto Aircraft engines went into widespread use - though Aircraft used the dual spark systems for a very different reason.

Atkinson-Style engines were patented in the 1890's... orginally they were made for pumping water or running sawmills.

Electronic Valve control (Direct Electrically-Actuated Valves) are still in their infancy... This will be a game-changer if they can be made to cycle reliably through millions of cycles. Variable Valve timing was experimented with in a very crude form in some Radial engines in the 1930's, and again on some 4 stroke marine diesels made by MTU in the 1950's.

Large Marine Diesels have been cutting cylinders from use for decades, as well as a few diesel locomotives.

Die Cast cylinders were developed in the 1950's-1960's by Honda; the first Nikasil Bores came into wide use in the 1960's.

The concept of engine balancing was well-understood even in the 1930's...some engines used this, and a very few required it: most Wankels don't handle imbalance very well.

Forged Crankshafts have been around single the 1950's - Cryogenic Stabilization was known at the time, but not applied to so large a part.

In terms of performance increases, most of the "newer" innovations touted are not new: rather they have finally become economically practical to mass produce. Some of the developments you mention have little to do with ICE development: Catalytic converters do not really help engine performance (though modern exhausts systems which use them, certainly do not hinder ICE performance.)

Unleaded fuel was made practical due to better combustion chamber designs, and hardened Valve Seats/ Stainless Steel Valves.

Most of the "innovations" we are being sold these days relate to improvements in how the ICE performs over a wide range of engine speeds. Most of the performance features we see in variable RPM engines could be discarded or optimized far more efficiently for a single-speed engine if we disconnect the Crankshaft from the Wheels completely: Gasoline-Electric or Diesel-Electric automobiles have the potential to increase thermal efficiency into the high 40 percent range (Fuel to Work).