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Previous work on the cooling jackets of the Cummins L10 engine revealed flow separation, and low coolant velocities in several critical regions of the cylinder head. The current study involved the use of detailed cooling jacket temperature measurements, and finite element heat transfer analysis to attempt the identification of regions of pure convection, nucleate boiling, and film boiling. Although difficult to detect with certainty, both the measurements and analysis pointed strongly to the presence of nucleate boiling in several regions. Little or no evidence of film boiling was seen, even under very high operating loads. It was thus concluded that the regions of seemingly inadequate coolant flow remained quite effective in controlling cylinder head temperatures. The Cummins L10 upon which this study has focused is an in-line six cylinder, four-stroke direct injection diesel engine, with a displacement of 10 liters.

The paper presents the latest research results on the piston ring free shape. A new free shape measurement method with optical gauging was developed. Three numerical models to compute the contact force distribution of piston ring were developed using finite element analysis (FEA). These numerical methods have been compared each other, and validated with the experimental results of ring deformation in a ring gage. The contact force distribution of a piston ring at working condition was also studied. It consists of the ring thermal boundary conditions (RTBC) validation, 3-D FEA thermal analysis and thermal contact force computation based on validated wire-cable element model. The RTBC for heavy duty diesel engine has been validated for the first time using a CUMMINS L10 engine test. Three different free shapes have been tested. The wear band measurements of tested rings all show tremendous improvements over the standard top ring.

An inexpensive, flexible and convenient finite element analysis system can be implemented with limited capital and resources. A system of this nature can be a functional tool of the designer and stress analyst for the analysis of many types of mechanical components. The finite element models generated by this system can approach a high degree of complexity with a small time investment compared to the time required to do this job without the aid of the system described.