Analysis of block vibrations induced by combustion chamber pressure in a diesel engine

The paper describes an experimental methodology devised to study engine block displacement of internal combustion engine in the radial direction due to combustion force. This force produced in the cylinder varies with the chamber profile since flow parameters are influenced by the combustion chamber profile. Combustion effectiveness fluctuates depending upon flow parameters. To correlate between combustion and injection and to detect faults in the injection system it is necessary to supervise the combustion in the individual cylinders. This can be accomplished by evaluating the crankshaft speed at the flywheel. Speed is directly related to combustion by means of indicated pressure and torque. Different combustion chamber profiles were taken for the analysis along with speed and load as the design variables. The displacement and time-domain frequency for all the profiles were compared. The results provide displacement induced by the combustion pressure, uncertainty in combustion processes and nonlinear vibration of the engine block. This new approach in engine parameter design gives insight on the vibrational processes in the case of different chamber profiles as well as sources of noise in the diesel engine.