Comments by "Terje Oseberg" (@terjeoseberg990) on "Opposed Piston Diesel Engines Are Crazy Efficient" video.

  1. Ernst Otto Oehler, 2-stroke engines have bad emissions because when the intake air pushes the exhaust out, if you want to maximize performance (not efficiency) you design it to make sure it pushes ALL the exhaust out. This results in some unburnt air and fuel to be pushed out the exhaust as well. This unburnt fuel in the exhaust is the cause of bad emissions for 2-stroke engines. However, this engine and any direct injection 2-stroke engine can use clean air with no fuel from the intake to push all the exhaust out with no unburnt fuel. Then, after the exhaust port has closed, or the exhaust valve has closed, it can inject the fuel into the compressed air in combustion chamber. This completely eliminates the bad emissions that are typical of 2-strokes.
    12
  2. Iz Meorbin, Please explain why this engine spits unburnt oil.
    3
  3. Satunnainen Katselija, I never said diesels were clean. What I did was explain why a typical 2-stroke is spewing out unburnt fuel. They also spew out unburnt oil along with that fuel. Regarding diesel, I know they pollute more than gas engines. Is it possible to fix this? I have no idea. And I too am disappointed that they failed to mention anything about emissions in this video.
    2
  4. Jim Kiley, Regarding the 2 levers with the apposed pistons vs. 1 lever on a conventional single crankshaft engine. In order to obtain the proper compression ratio, the lever arm will be half as long on the 2 lever engine than on the single lever engine. Therefor the torque produced on each of the 2 levers will be half that of the 1 lever. The net result is that half the torque times twice the number of levers is the same as twice the torque on half the number of levers.
    2
  5. Sean Angermeier, Is that peak torque at the crankshaft? Or after being geared down (IE: after the transmission)? Because with gears, you can create as much torque as you want. What's more important is how wide is the power band? The wider the power band, the fewer gears you need in your transmission.
    1
  6. I believe that the torque of diesel engines is higher than the torque of gas engines because the greater compression ratio of diesel engines requires a longer lever than that of the lower compression ratio gas engine. The compression ratio is nearly double, so the lever arm on the crankshaft is nearly double the length and thus nearly double the torque for the same size piston. However, since that piston is moving nearly twice as far, the displacement will be nearly double as well.
    1