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The rapidly growing complexity and the growing cross linking of powertrain components leads to longer development times, especially in the vehicle calibration process. The number of systems which need to be fitted to each other and the number of parameters to be calibrated in the particular systems are increasing tremendously. The extensive use of simulation promises to reduce the calibration effort by providing pre-optimized parameter sets. This paper describes a new simulation methodology by the interlinking of advanced vehicle simulation and evaluation tools, in particular the AVL-tools CRUISE, VSM and DRIVE. This methodology allows to semi automatically pre-optimize powertrain and vehicle parameters before hardware is involved. So far the pre-calibration of vehicle and powertrain parameters by simulation was not satisfying because of the missing of a reliable evaluation tool for the produced simulation results.

The paper describes the methods used to select appropriate engines for renewing an existing fleet of fork lift truck models with new Diesel and LPG engines. The target was to achieve a better performance with the new engines and to find a better cost / benefit ratio for the customer. The aid of a simulation was used to fulfill this task. Selecting suitable engines from a variety of industrial and mass production passenger car engines which fulfill above requirements seems to be an easy task on first sight, but looking at the details the matter becomes more complex. Of particular interest were the effects of replacing naturally aspirated (NA) engines by smaller swept volume turbocharged (TC) engines. A power train simulation model including the hydraulic lift part was developed and used for Diesel and LPG engines. For several different operating situations and load profiles a set of simulations was performed for different engines.

After a review of the current status of development of heavy-duty direct injection diesel engines (all turbocharged and intercooled) technologies to meet US-EPA 1994 heavy-duty diesel emission standards are discussed. Special attention is given to the NOx-particulate trade-off and to the various particulate fractions (carbon, lube oil, sulfates), and to measures for their reduction by internal means. A major part of the paper addresses the application of oxidation catalysts as a very efficient and cost-effective aftertreatment device to burn off soluble particulate fractions, CO, HC, odorants and PAH. The paper concludes with an outlook on foreseeable developments of the heavy-duty diesel in the future.