The representative interactive flamelets(RIF)model was coupled with the large eddy simulation(LES)method to predict the turbulent combustion in a diesel engine.The new approach is specifically suitable for the simulation of the complicated combustion processes in internal combustion engines because the multi-scale and highly-transient turbulent motion can be well reproduced，and detailed chemical mechanism can be used.By combining the KIVALES-RIF code developed in previous work with a reduced n-heptane oxidation mechanism，the combustion processes and emission characteristics of a single-cylinder version of the Caterpillar 3400 series heavy-duty diesel engine was simulated under the baseline operating condition.The results indicated that the predicted ignition delay，in-cylinder pressure，heat release rate and pollutants emission levels were in good agreements with the experimental results.Comparison between the predictions of the Reynolds averaged Navier-Stokes(RANS)method and the LES method showed that the turbulence model played an extremely important role in the prediction of the combustion processes.