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A numerical simulation method by transfer matrix method is proposed to compute the vibration stress waveforms of a V-type, 8 cylinder diesel engine crankshaft in this work. This method will be able to predict the conditions of vibration stresses and be useful to design a crankshaft. The accuracy of this numerical method is confirmed by comparing the simulation results of the computation with the measured data. As a result of the comparisons with the measured data, it has been assured that the vibration stress waveforms can be computed with adequate accuracy by considering from 0.5-th to either 10-th or 12-th order per 0.5-th order harmonic components of exciting forces for a 4-cycle engine.

It is the purpose of this paper to make clear the effect of typical torsional viscous-friction damper on the reduction of the axial, torsional and two directions of lateral vibrations from the analytical and experimental points of view. At first, a typical type of the torsional viscous-friction damper is fitted to a high-speed diesel engine and the axial, torsional and two directions of lateral vibration displacements at the pulley end are measured in order to investigate the effect of the damper on the reduction of these vibrations in the three dimensional space of the engine shaftings from the experimental point of view. Next, the characteristics of the axial, torsional and two directions of lateral vibrations of the engine shaftings are investigated by three dimensional analysis of forced vibration by the transfer matrix method, which has been developed by the authors.

This paper refers to a numerical calculation method, in which the transition matrix method is employed. The method estimates torsional vibration amplitude of a crankshaft with a rubber damper by taking the dynamic characteristics of the rubber part into consideration. Firstly, the rubber part is replaced with a three-elemental Maxwell model, which is determined by the results of static tests, such as stress relaxation test, creep test and static torsional test. The basic data used for the determination of the element values on the Maxwell model are obtained by these tests. Secondly, the vibration system of a crankshaft with a rubber damper is replaced with a linear lumped model, in which the torsional stiffness and damping coefficient of the damper rubber part are decided by using the element values of the Maxwell model.

The regulations of Formula SAE® competitions restrain design, tuning, and improvement on engine in order to keep safety on driving. The competitors have basically chosen a 600 cc, 4-stroke engine for motorcycle according to the regulations. Therefore, it is necessary for higher engine performance to improve combustion by investigation of air intake and exhaust component design while the regulation agreement is the most important factor. Recently, many competitors have been using a high performance Engine Control Unit (ECU) easy to suitably control the engine combustion. The competitors can focus on optimization of the intake and exhaust components using ECU. Best tuning of each component is very difficult work because the design factors of these components have complicated relations with engine performance. Here, our interest is a method to reduce the optimization time of the system.

Formula SAE is one of the competitions of the manufacturing education for students, which is held by SAE. The competition consists of the static events and the dynamic events. The static events have three competitions of presentation, cost and design, and the dynamic events are acceleration, skid pad, autocross and endurance with fuel consumption. To get the higher rank in this competition, we must win the dynamic events with the high allotment points. For the purpose of the winning, we should have some advantages more than the other universities. We aimed at raising engine power and drivability. There are some ways to get engine power up such as the combustion improvement, the change of the cam profile and supercharging. We tried to install a commercial turbocharger to a normal aspirated multi-cylinder engine for Formula SAE under the SAE regulations.