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Complete Engine Thermal Model, a Comprehensive Approach
Abstract:
Upcoming engine generations are characterized by both a general trend of increased specific-power and higher efficiency. This leads to increased thermal loads, compromising reliability, and simultaneously to a limited amount of heat under ordinary engine use. Heat is a valuable resource in providing passenger comfort and emission control. For these reasons the subject of engine thermal management is receiving increasing attention.
This work presents a comprehensive study of the complete engine thermal behavior at relevant running conditions: rated-power, peak-torque and ordinary use. The work is further extended to the engine warm-up period. The result is a high-resolution complete engine thermal model, capable of simultaneously reporting the local temperature of any engine part, and the global engine heat balance at any engine load. All different heat sources and heat sinks are studied in detail and implemented in the same platform, allowing the direct study of their mutual thermal interactions. Among these are: combustion, friction, boiling and external radiation. The space-time resolved boundary-conditions describing heat sources and sinks are obtained from measurements as well as models.
To widen the area of application, the high-resolution model is further translated in a fast-running model for direct integration in complete vehicle thermal models in order to perform complete system analysis.