New Heat Transfer Correlation for an HCCI Engine Derived from Measurements of Instantaneous Surface Heat Flux 2004-01-2996
An experimental study has been carried out to provide qualitative and quantitative insight into gas to wall heat transfer in a gasoline fueled Homogeneous Charge Compression Ignition (HCCI) engine. Fast response thermocouples are embedded in the piston top and cylinder head surface to measure instantaneous wall temperature and heat flux. Heat flux measurements obtained at multiple locations show small spatial variations, thus confirming relative uniformity of in-cylinder conditions in a HCCI engine operating with premixed charge. Consequently, the spatially-averaged heat flux represents well the global heat transfer from the gas to the combustion chamber walls in the premixed HCCI engine, as confirmed through the gross heat release analysis. Heat flux measurements were used for assessing several existing heat transfer correlations. One of the most popular models, the Woschni expression, was shown to be inadequate for the HCCI engine. The problem is traced back to the flame propagation term which is not appropriate for the HCCI combustion. Subsequently, a modified model is proposed which significantly improves the prediction of heat transfer in a gasoline HCCI engine and shows very good agreement over a range of conditions.
Citation: Chang, J., Güralp, O., Filipi, Z., Assanis, D. et al., "New Heat Transfer Correlation for an HCCI Engine Derived from Measurements of Instantaneous Surface Heat Flux," SAE Technical Paper 2004-01-2996, 2004, https://doi.org/10.4271/2004-01-2996. Download Citation
Junseok Chang, Orgun Güralp, Zoran Filipi, Dennis N. Assanis, Tang-Wei Kuo, Paul Najt, Rod Rask
University of Michigan, GM Research and Development Center
2004 Powertrain & Fluid Systems Conference & Exhibition
Homogeneous Charge Compression Ignition-SP-1896, SAE 2004 Transactions Journal of Engines-V113-3