Thermal management of an internal combustion engine focused on vehicle performance maximization: A numerical assessment

Abstract

In extreme ambient conditions, engine temperature and air charge temperature (ACT) can be so high that they compromise the vehicular performance. To preserve the structural engine reliability, it is necessary to reduce the load through an increase in the engine speed to maintain the power output, which minimizes fuel conversion efficiency degradation. However, high engine speeds also lead to enhanced friction losses and combustion frequency, which reduces the engine thermal efficiency. Therefore, this work seeks to numerically study the best thermal management strategy to minimize performance losses arising from an engine power derate strategy, while also optimizing the design of a cooling system to withstand extreme engine stress conditions, characteristics of the Davis Dam tests. Different radiator lengths and fan power were numerically simulated to conclude about the most influential parameter on fuel consumption in the FTP-75 + HWFET cycle. The results showed positive effects from the engine power derate strategy, and the engine speed control was able to mitigate up to 23% derate by cooling temperature. There was a 0.8% increase in fuel consumption for every 2.5% aerodynamic drag coefficient increase, which reinforces the need to perform robust thermal management procedures instead of oversizing a vehicular cooling system for high-load operation.