Tribotronic Analysis of Internal Combustion Engine Compression Ring

Abstract

The influence of operating conditions of the compression rings on the engine power losses affects confoundedly the design of the Internal Combustion Engines (ICEs). Normalized parameters such as Friction Mean Effective Pressure (FMEP) were used to regulate power losses. The purpose of this work was to create a primary control model of the friction mean effective pressure using an automatic control system. This study incorporates the creation of a mixed-hydrodynamic model for the top compression ring in MATLAB computing environment. The load of ring asperities was predicted using Greenwood-Tripp stochastic model. The pressure distribution along the ring face-width was determined using Reynolds equation through finite difference method with the half-Sommerfeld boundary condition for cavitation outlet zone. This was accomplished by finding the maximum ring pressure for a range of engine speeds and lubricant temperatures. Additionally, the computed results concerning the maximum pressure and the PID controlled characteristics are proposed and compared using a cavitation model. Regarding the automatic system, a PID controller was built using SIMULINK. The numerical results showed that FMEP could be the effective parameter in order to control the engine operation and to proof the tribotronics design in an Internal Combustion Engine.

Keywords

• compression ring
• mixed-hydrodynamic lubrication
• reynolds equation
• friction mean effective pressure (fmep)
• matlab
• automatic control