21. Animation showing the "'four-stroke cycle "'of an internal combustion engine, the most commonly used for automotive and industrial purposes today. 22. In addition, four-stroke cycle flat-fours have a problem common to all four-cylinder engines : the power strokes do not overlap. 23. Knock occurs when the peak of the combustion process no longer occurs at the optimum moment for the four-stroke cycle . 24. However, in the real world probably 95 % of the combinations have no really useful relevance to the four-stroke cycle . 25. American World War II Diesel-electric submarines operated on two-stroke cycle, as opposed to the four-stroke cycle that other navies used. 26. American World War II Diesel-electric submarines operated on two-stroke cycle , as opposed to the four-stroke cycle that other navies used. 27. However, Detroit Diesel 2-stroke cycle engines commonly use oil cooled by water, with the water in turn cooled by air. 28. I think the two-stroke cycle article could use a pollutants section . moink 21 : 04, 4 June 2006 ( UTC) 29. The engine is a two-stroke cycle design, capable of producing, and doing up to about on level ground, while getting about. 30. Glow engines which operate on the four-stroke cycle , whether using ordinary poppet valves or occasionally opposed twin and radial engine layouts.