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Replacing the metal car roof with conventional solar modules results in the increase of total car weight and change of center of mass, which is not preferable for car designing. Therefore, weight reduction is required for solar modules to be equipped on vehicles. Exchanging glass to plastic for the cover plate of solar module is one of the major approaches to reduce weight; however, load bearing property, impact resistance, thermal deformation, and weatherability become new challenges. In this paper a new solar module structure that weighs as light as conventional steel car roofs, resolving these challenges is proposed.

The torsional vibration of diesel engines has become severer with the increase of exciting force by higher pressure. Therefore, the running crankshaft is highly stressed owing to the large torsional vibration. Then, torsional viscous fluid dampers of high performance have been employed in high mean effective pressure diesel engines as a measure for vibration reduction. As the dynamic characteristics of the dampers have such a great influence on the vibration of the engine crankshaft system that they cannot be ignored, the viscosity of the silicone oil and the peripheral and lateral gaps of the dampers are diversely varied in the experiment. As the equipment for the measurement of torsional vibration displacement, a phase-shaft type torsiograph equipment was adopted so as to make it easy to measure simultaneously angular displacements of the casing and the inertia ring.

The dynamic characteristics of conventional viscous-friction dampers are investigated in this paper by adopting simultaneous vibration measurement method at two points. The vibration displacements of the damper casing and the inertia ring can be simultaneously measured in this method. It has become possible that the more detailed dynamic characteristics of the viscous-friction damper can be grasped by the method. Especially, it is an effective method to grasp the behaviors of the inertia ring and the damper casing for clarifying the effect of the silicone fluid on the torsional vibration of crankshaft system. The damper casing was made of acrylic resin in order to measure the behavior of the inertia ring on engine operation. It is possible to measure the torsional vibration displacements waveforms by the optical signals from pulse tapes stuck in both peripheral sides of the damper casing and the inertia ring.

This paper shows a design and performance prediction methods for a miniaturized Stirling engine, in order to develop a small portable generator set. First, a 100 W class Stirling engine is designed and manufactured. In order to miniaturize the engine, unique type heat exchangers were applied. A regenerator was located in a displacer piston. For a piston drive mechanism, a Scotch-yoke mechanism which was useful to realize the small-size engine without any lubricating device, was adopted. Next, an analysis model for the miniaturized engine is developed to improve the engine performance efficiently. The pressure in the working space is analyzed by an isothermal analysis which takes into account a gas leakage through a piston ring and pressure loss in the heat exchangers. To estimate a shaft power, the mechanical loss and the buffer loss, which is caused by a pressure change in a crank case are considered on the analysis model.

The cheap and compact rubber dampers of shear-type have been widely employed as the torsional vibration control of the crankshaft system of high-speed, automobile diesel engines. The conventional rubber dampers have various rubber forms owing to the thorough investigation of optimum dampers in the design stage. Their rubber forms can be generally grouped into three classes such as the disk type, the bush type and the composite type. The disk type and the bush type rubber dampers are called “the basic-pattern rubber dampers” hereafter. The composite type rubber part is supposed to consist of the disk type and the bush type parts, regarded respectively as the basic patterns of the rubber part, at large. The dynamic characteristics of the vibration isolator rubber depend generally on temperature, frequency, strain amplitude, shape and size effects, so it is difficult to estimate accurately their characteristics.

Automotive diesel engines have been developed with the aim of achieving higher performance and lighter weight. Since the torsional vibration stresses of the crankshafts have become severer with increase of specific power, torsional vibration rubber dampers of shear-type have been widely used in order to reduce the vibrations. However, the dynamic characteristics of the dampers depend on amplitude, frequency, temperature and secular change effects. Therefore, the dynamic characteristics should be separately investigated with every influence factor. This indicates that it is difficult for the damper designers to predict the dynamic characteristics of the torsional vibration dampers in engine operation. This paper refers mainly to the dynamic characteristics of shear-type torsional rubber dampers with rubber vibration isolator hardened by secular change.

The unknown characteristics of the bending vibration coupled with torsional vibration (hereafter called“coupled torsional, bending vibration”) are investigated from the experimental and analytical viewpoints. The torsional and bending vibration stresses of the crankshafts of a 6 cylinder, in - line engine and an 8 cylinder, V - type engine are measured first in order to investigate experimentally the characteristics of the coupled torsional - bending vibrations. Next, the displacements, moments and stresses of the torsional and bending vibrations of the above - mentioned crankshaft are calculated by 3 dimensional, forced vibration analysis of the crankshafting of the V 8 engine using the transfer matrix method, which has been developed by the authors. Finally, the experimental results are compared with the corresponding calculated results and the characteristics of the bending vibration stresses coupled with the large torsional vibrations are made clear.

The dynamic characteristics of the rubber dampers of compression type have been investigated in comparison with the conventional rubber dampers of shear type. The compression - type damper has been designed so as to produce compression force on the rubber part when torsional torque acts upon it. This research report proposes the design method of the new compression - type rubber dampers. The new rubber dampers have been fabricated on an experimental basis in accordance with the design method formulated by us. With the new dampers equipped in a 6 - cylinder, in - line diesel engine, the dynamic characteristics of stiffness and damping have been examined through experiments. In comparison of the experimental results between the new compression - type rubber damper and the conventional shear - type rubber damper, it has been revealed that the compression - type rubber damper has some advantageous characteristics.

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 computation for vibration displacements and stresses of a crankshaft with a shear type rubber torsional damper by the three dimensional transfer matrix method. The accuracy of this computation method is confirmed by comparing computed results with measured ones. Especially, in this work, the numerical computation method is proposed to compute the vibration displacements and stresses by means of replacing the rubber part of rubber torsional damper with a spring-dashpot model. Then dynamic characteristics are estimated by the complex torsional stiffness derived from a three-element Maxwell model. As a result the torsional vibration stress and bending vibration stress and vibration displacements (angular and lateral displacements) can be computed with an adequate accuracy. This computation method is applicable to predicting the conditions of vibration displacements and stresses, and will contribute to optimum design of the crankshaft.

Described herein is an experimental and theoretical study of the dynamic properties of torsional viscous-friction dampers for use on Diesel engines and the characteristics of torsional vibration of the engine shaftings. At first, three kinds of dampers are fitted to a 14.3 liter, V-type, 8-cylinder Diesel engine and the torsional vibration displacements at the pulley are measured in order to investigate the characteristics of torsional vibration of the shaftings with the damper. The kinematic viscosity of silicone oil is diversely varied in this experiment. It is confirmed that an optimum viscosity exists for each damper from an experimental viewpoint. Next, the dynamic properties of the dampers and the characteristics of torsional vibrations of the engine shaftings are investigated by 3 dimensional analysis of forced vibration by the transfer matrix method, which has been developed by the authors.

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.

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.