1 0 0 0 OA 燃料噴射弁の開弁圧力低下による燃焼の変化とその原因解明
- 著者
- 山谷 尚弘 見上 博 張 勁 平澤 良男 石原 外美 手﨑 衆
- 出版者
- 公益社団法人 日本マリンエンジニアリング学会
- 雑誌
- マリンエンジニアリング (ISSN:13461427)
- 巻号頁・発行日
- vol.53, no.1, pp.140-146, 2018-01-01 (Released:2018-03-14)
- 参考文献数
- 10
Fuel injection pressure decreases in four-stroke diesel engines after extended operations. Poor combustion caused by the pressure drop is a serious problem that can lead to environmental pollution. Several factors have been considered to be behind mechanisms to decrease fuel injection pressure, but the details of such mechanisms are still unknown. Up until now, only limited numbers of studies have been conducted to define these mechanisms. In this study, we clarified that stress relaxation, buckling and metal fatigue of the pressure regulating spring in the fuel injection valve contribute to lowering injection pressure. We also found that the lowering of injection pressure causes early and prolonged injection in diesel engines.
1 0 0 0 OA 熱応力を伴う転がり接触によるき裂表面摩擦を考慮した三次元内部傾斜き裂の進展挙動
- 著者
- 清水 理能 五嶋 孝仁 内山 隆嗣 石原 外美
- 出版者
- 一般社団法人 日本機械学会
- 雑誌
- 日本機械学会論文集 A編 (ISSN:03875008)
- 巻号頁・発行日
- vol.71, no.711, pp.1546-1553, 2005-11-25 (Released:2011-03-02)
- 参考文献数
- 16
This paper considered three dimensional internal inclined crack growth behaviors due to repeated rolling thermoelastic contact. In this analysis, crack is modeled as an internal inclined planar crack in a three dimensional half-space. Rolling contact is simulated as a long and narrow distributed load with both normal and shear components moving with constant velocity. In comparing the shearing force with the frictional force of crack surface, the phenomenon of stick and slip were considered. At first, stress intensity factors along the crack contour are analyzed using high carbon chromium bearing steels. Next, numerial results of crack growth contours are given based on a modified Paris power low. And fatigue life is estimated by maximum crack growth. The shapes of crack contour and fatigue life are calculated under various conditions, which change sliding ratio, frictional coefficient, angle of inclined crack and friction coefficient of crack surface. As results, when the friction of crack surface is large, the crack progresses greatly in the direction at no friction of crack.