The knowledge of heat rejection of combustion engines is essential for the design and layout of automotive cooling systems with respect to peak performance but also with respect to thermal warm-up for low part load operation. For this purpose special designed heat rejection test benches are used to predict heat rejection to the coolant, the oil and to the ambient for different operating conditions at various fluid temperatures. The effort is generally very high and the prediction fidelity in the early prototype stage of the engine is often not very reliable.
As an alternative, InDesA will present and outline an approach to predict heat rejection which is basically built on the virtual product creation process including some standard test procedures. The approach is built around a detailed STAR-CCM+® engine model embedded in an under-hood environment. Combustion and exhaust temperatures are derived from 1D engine process simulation whereas friction losses will be obtained from pressure indication and tear down measurements. This methodology will not only be capable to predict heat rejection to the coolant and engine oil for high performance but will also allow to asses thermal management technologies such as split cooling, controlled water pumps, water cooled exhaust manifolds or engine encapsulation.