Prediction of Wear in Start–Stop Systems Using Continuum Damage Mechanics

Abstract

A vehicle start–stop system automatically shuts down and restarts the internal combustion engine to reduce the time the engine spends idling, thereby reducing fuel consumption and emissions. For the start–stop system to work, the engine must be at a certain temperature and conditions. If the engine is too hot, the system may not activate. This study explores the tribological characteristics of the start–stop system by applying principles of Continuum Damage Mechanics (CDM) to predict both the lifespan and wear volume subsequent to the start–stop cycles. A series of pin-on-disk tests were conducted to evaluate the efficacy of the modeling and predictions. The results from these tests were compared to the CDM predictions, demonstrating satisfactory accuracy. Additionally, a Finite Element Method (FEM) analysis was employed to model temperature variations during the start–stop cycles. Findings indicate that an increase in consecutive start–stop cycles impedes the system’s ability to sufficiently cool, thereby increasing wear. Conversely, extending the duration of the stop phase reduces wear and enhances the system’s lifespan.