# Effect of Cylinder De-Activation on Diesel Engine Torsional Vibration

Effect of Cylinder De-Activation on Diesel Engine Torsional Vibration

Introduction:  The mechanical efficiency of a multi-cylinder IC engine is reduced when operating with part load. One solution here to reduce losses is to de-activate cylinders. This effectively means that one or more cylinders are sealed-off, without fuel injection, or any form of combustion or gas exchange. De-activation does however change the torsional vibration characteristics of the engine, is some cases problematically. This problem is to examine this phenomenon.   Find the natural frequencies for normal 6 cylinder inline diesel engine. Should use normal Fourier analysis gas pressure, assuming it to be perfectly periodic which in actual it is not. Have to represent it like ? order, 1 order & 1 ? order, basically an increment of ? order. The frequencies must be calculated in first order then again 2nd order as for 4 strokes there is half orders as well. This should be displayed on a Campbell diagram. Then find the natural frequencies of the same engine by cutting off cylinders one by one displayed on Campbell diagram.   ==============  The method used should be like representing the 6 cylinder in line engine as an inertia & mass system. Then resolve using eigenvalue vectors. using this find natural frequencies at different levels and plot them on Campbell diagram.