Marine Engineering

Super long stroke means increased swept volume allowing more mass of air to be drawn into the cylinder which in turn allows more fuel to be burnt, hence increasing power output. Super long stroke increases piston travel time and thereby decreases crank speed so more time for combustion during the stroke. The efficiency of Large dia propellers is best at slower RPM.With super long stroke we can have slower RPM of engine with no change in mean piston speed of the engine. Classification of engine based on stroke/bore ratio: Short stroke : 2.6-3.2 Long stroke : 3.2-4.0 Super-Long stroke : 4.0-4.7 Ultra-Long stroke : >4.7 These engines allow for low quality of fuel to be burnt as there is more time available for fuel combustion. With increase in stroke length we have an advantage of burning dirty fuel/low grade fuel at min rev/low speed with good efficiency. This also results in proper utilization of fuel resulting in reduction of NOx generatio...