Local pressure leveling design method for multi-link mechanism for variable compression ratio engine
- Delivery
- Available on this site
- Format
- Price
- Non-members (tax incl.)：￥1,100 Members (tax incl.)：￥880
- Publication code
- 20239254
- Paper/Info type
- Other International Conferences
- Pages
- 1-6(Total 6 p)
- Date of publication
- Aug 2023
- Publisher
- JSAE & SAE
- Language
- English
- Event
- 2023 P, E&L
Detailed Information
| Category(E) | TL1 Power Cylinder Systems and Components |
|---|---|
| Author(E) | 1) Takayoshi Furukawa, 2) Hiroki Asajima, 3) Takashi Tanabe, 4) Satoru Ookuma, 5) Kentaro Kawahara |
| Affiliation(E) | 1) Nissan motor Co., Ltd., 2) Nissan Motor Co.,Ltd., 3) Nissan Motor Co.,Ltd., 4) Nissan Motor Co.,Ltd., 5) Nissan Motor Co.,Ltd. |
| Abstract(E) | Nissan Motor Co., Ltd. has started mass production of the world's first mass-produced engine equipped with a variable compression ratio system. This engine adopt a multi-link crankshaft rotation mechanism with eccentric control shafts connected to all cylinders in order to achieve seamless and simultaneous variable compression ratio for all cylinders. In this mechanism, the part corresponding to the conventional connecting rod is divided into an upper link and a lower link, and the input load from the piston to the crankshaft is approximately doubled compared to the conventional connecting rod mechanism due to the principle of leverage.In the design of the lower link bearing, the bearing width in the direction of the crankshaft is increased in order to keep the bearing nominal surface pressure, which is an index of durability, to the same level as the conventional connecting rod bearing. Therefore, a challenge was to make the entire sliding surface uniform.Though the slit structure of the lower link sandwiching the upper link contributes to leveling the surface pressure in the circumferential direction, due to the increase in edge rigidity associated with the adoption of this technology, the problem of increased edge contact surface pressure arises.In order to solve this problem, a "local surface pressure leveling design method" is essential to prevent localized concentration of the bearing surface pressure generated by the received load. As a solution, predicting the state of the sliding surface before load input, taking into account the deformation of the housing, and prediction of local surface pressure increase at edges and oil holes by combination with slit structure by FEM/EHL.By setting the barrel shape deviation in the circumferential direction of the bearing against the barrel shape of the shaft sliding surface, the generated surface pressure in the axial direction is dispersed/reduced. |
