Comments by "David Elliott" (@davidelliott5843) on "Opposed Piston Diesel Engines Are Crazy Efficient" video.

I'm sure you are right. Car and bike manufacturers are well known for not thinking out of the box on basic engine technologies. But to be fair Ford had a fleet of 2 strokes running in the Ka during the 1990s. It was held back by EU regulations so the Ka was marketed with the old tech crossflow 4 stroke. Konisegg(sp?) has a 4 cylinder 4 stroke turbo that has no cam shaft or cam drive. Its all electronically controlled and proven to work extremely well. Do we have them on the road? Do we heck!
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Check out the Napier Deltic invented for high speed torpedo boats. Two stroke opposed pistons with three crankshafts and typically three rows of six cylinders and 36 pistons. They were timed so that one piston lead the other to open the exhausts before the inlets were opened. The third crank ran backwards to allow every row of cylinders to operate correctly.
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@Opa_der_Kranke It is a boxer but pistons oppose rather than push apart. Another interesting design is a four cylinder radial 2-stroke. It has all four con rods running on one (wide) crank pin. There is no master rod as seen on 4-stroke radials so the engine is as simple at the crank end as it is at the cylinder head. They give four power pulse per rev so torque vibration is very low. The top end and crank are in perfect balance so the engine is almost as smooth running as a rotary. The bottom end is dry sumped so oil consumption is not an issue.
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@LucioFercho They were given the design as part of WW2 war reparations.
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Back in the 1980s I worked with Terex TS40 (40 cubic yard) earth scrapers used to move coal at a power station. Some had Cummins turbo diesels (sorry cant remember the model) and some had Detroit 2 Strokes in The Cummins were regularly blowing turbos sometimes taking cylinders with it. The Detroits just ran and ran. Never any trouble and always very powerful. They blew black smoke when driver floored the accelerator pedal, but at constant load were very clean. Cummins would smoke when worked hard. Interestingly, the Cummins powered machines had an eccentric balance weight on the rear engine crank that generated considerable vibration. If that was not fitted the rear engine would quickly break it's crankshaft. The cause was harmonic vibration from the front engine. The Detroits never had that problem.
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Combine this with a rich premixed air fuel mixture injected by voice coil pistons. That gives an easily ignited mass of air and fuel surrounded by pure air for clean combustion. The ultimate opposed piston engine was the Deltic with three banks and three cranks 9 cylinders 18 pistons.
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Water injection generates steam as it internally cools the engine and reduces peak gas temperatures. The benefit is reduced particulates and Nox low enough t not need a post treatment with AdBlue. As others said the issue is needing a water tank at least as big as the fuel tank.
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@nimblemotorsports 2 strokes running fuel and air through the crank case wear rapidly because uneven (poor) combustion causes the piston and crank loads to fluctuate badly at part load. Run continuously at >75% load and they have a very long service life, but for anything other than power generation that's just not a useful option. Direct injection strokers like the new Rotax ETEC engines solve most of those problems. They breathe clean air and only feed fuel direect into the combustion chamber when power is wanted. They don't get the widely varying fuel air mixtures, air flow reversals, etc that make "normal" 2 strokes so dirty, wasteful and short-lived.
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Check out the DieselAir two stroke opposed piston aero diesel. Also the Delta Hawk V4 and Zoche 4 cylinder radial. The latter is really simple. 4 cylinders arranged around a single crank pin. Sadly it relied on government funding so simply fizzled out.
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