Many thermodynamical problems on the cycle of the internal combustion engine have been dealt with by various authorities. The present author also deals with the same theme taking account of the following aspects : -1)The specific heats of actual gases vary with the temperature and pressure. 2)The chemical compositions of the working fluid vary to a great extent during the cycle. 3)The number of mols varies by the introduction of the fuel and blast air and also by the combustion itself. 4)Carbon dioxide and steam are dissociated at higher temperatures. 5)The heat of combustion is a function of the initial temperature at which the reaction takes place. This paper gives a record of actual complete tests on a Diesel engine of four-stroke cycle type developing 33B.H.P. at 230 rev/min The tests were made to investigate the behaviour of the engine at 4/4 and 3/4 loads applying the results of the forementioned thermodynamical considerations. Among the various experimental data, those for the cyclic variations of 1)the temperature of the working fluid, 2)the rate of heat exchange between the working fluid and the cylinder wall, 3)the total heat transmission coefficient and 4)the heat transmission coefficients due to the convection and also due to the radiation of carbon dioxide and steam in the working fluid may be interesting. Finally, the author proposes a 'standard air' for the working fluid of the standard engine for comparison with specific heats given by the following equations : -[numerical formula] He also devised an entropy chart applicable to any type of internal combustion engine as well as the standard air cycle.

View full abstract

It is well known that the secondary vibration occurs at half the whirling speed. Stodola has solved this problem, taking account of the rotary vibration of an eccentric shaft due to gravity. Even when the elasticity of the shaft varies with the direction of its bending, eccentricity was also assumed to account for the secondary vibration. In this paper, however, it is explained that, in such a case, the secondary vibration can be accounted for without considering the rotary vibration and accordingly the eccentricity.

View full abstract

When mild steel bars yield under combined torsion and bending, there are two kinds of yielding. One is the yielding principally under torsion, and the other principally under bending. In the latter case the following relation holds at yield points, [numerical formula]where σ_s is the greatest normal stress across the cross-section due to bending, and τ_s the greatest shearing stress on the cross-section due to torsion.

View full abstract

(I)Supplementary discussions of the first report. The creep curve consists generally of two parts; of decreasing deformation-speed, and increasing one. The former phenomenon is due to the strain-hardening effect. The mechanism of creep deformation comprises the local slip of non-plastic kind in crystal grains and the plastic deformation of grains. According to the past researches of ordinary tests under increasing load, the crystal deformation is a slip, and it depends only on the shear stress; moreover, the crystal has its own peculiar slip-planes, and the slip-systems take play successively in the polycrystalline structure. Taking the case of a simple tension, the shear stress is max. on the plane making an angle of 45 degrs. with the axis of the specimen. Therefore, among the proper slip-planes of the crystal, these are in the planes

View full abstract

In this paper, the author deseribes a method of increasing the wear resistance of cast iron to a great extent, without giving any unfavorable change in its structure and mechanical properties. At first, with various kinds of cast iron annealed at various elevated temperatures, the mechanical properties, structure and wear resistance were studied. As the result, it is stated that, in case that the cast iron is annealed at 500℃ in the ordinary atmosphere, the resistance to wear greatly increases, whereas its structure and mechanical properties remain practically unchanged. Next, the cause of increase of wear resistance is attributed to the internal oxidation of cast iron by oxygen in the ordinary atmosphere, from the fact that the same treatment as above carried out in non-oxydizing gases does not show any improvement of wear resistance, and further discussion is made on the mechanism of wear of cast iron. In the last, it is proposed, as one of the methods of increasing the resistance to wear of cast iron, to make the protective film such as iron oxide on the surface of iron faced to graphite flakes.

View full abstract