Fig. 2 The mode shapes
3. EXCITATION PHASE SHIFT BY DIFFERENT M.I.P. IN THE ENGINE CYLINDERS
Of potential interest was the investigation of the phase shift versus m.i.p. A large phase shift of the 6th order harmonic vectors (the excitation) for small variations of cylinder m.i,p. would result in de-coupling the vectors that at the resonance are in phase no matter the crankshaft or firing order configuration. The initial calculations [16] showed only a very small phase change for 1-2 bar m.i.p. difference in the cylinders. The study interval was increased from 5 to 18.7 bar m.i.p. The vector's phase was:
