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Due to ever soaring fuel costs and even more stringent emission regulations which require more elaborate technical efforts and unfortunately lead to a negative trend on fuel economy as well, todays and future trucking business is extremely challenged. These facts create an urgent requirement for the engine manufacturer to offer an engine with an optimized cost-benefit-ratio for the trucking business. Mercedes-Benz, as the leader in the European commercial vehicle market - of which e. g. high fuel costs, long maintenance intervals and high engine power-to-weight ratios have always been key characteristics - has developed a new class 8 engine for the US market. The MBE 4000 is a 6 cylinder inline engine in the compact size and low weight category, but due to its displacement of 12,8 liters it offers high performance characteristics like heavier big block engines.

The Institute of Transportation Studies at the University of California, Davis (ITS-Davis) has brought together a group of public and industrial partners to demonstrate and evaluate the Siemens-Westinghouse Urea-Selective Catalyst Reduction System (SINOx™). The SINOx System has the potential to generate major reductions in nitrogen oxides (NOx) and the volatile organic fraction (VOF) of particulate (PM) from heavy-duty diesel engines, without increasing fuel consumption and carbon dioxide (CO2) emissions. This demonstration began with engine bench testing at Detroit Diesel Corporation to calibrate the system to attain 1 g/bhp-hr NOx emissions in the transient portion of the US-FTP on a 1999 Series 60 engine that has a 4 g/bhp-hr emission level. The second phase of the project entails an on-highway demonstration of a set of ten, Freightliner Class 8 heavy-duty diesel vehicles. These vehicles are part of the Valley Material Transport fleet based in French Camp, California.

Simultaneous engineering techniques have been applied to a SMC truck hood to reduce the lead-time for production introduction from 22 months to 12 months. Several other technologies were also applied to insure a successful product introduction in this reduced timeframe: computer definition of the hood surface for accuracy, RTM prototype tooling for early design tryout and durability testing, Finite Element Analysis to further confirm durability of the hood structure, and brittle lacquer combined with strain gaging to provide life data using a hydraulic road simulator for load inputs.

This paper derives a parametric equation for predicting the fuel economy of on-highway heavy-duty trucks. The accuracy of this equation is compared to actual vehicle MPG results. Based on this equation, the relative importance of the numerous parameters which affect the fuel economy of on-highway heavy-duty vehicles are calculated and discussed. To illustrate the value of this methodology, the development of the newest Freightliner EnergySaver package is described and the results from a cross-country fuel economy test of this package are presented. Using these same methods, the future for increasing on-highway heavy-duty truck fuel economy is explored.