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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.

As part of a comprehensive strategic product initiative the most important commercial vehicle manufacturer - Mercedes-Benz AG - is step by step renewing its entire product range. This primarily refers to the heart of the vehicles - the engine. After the OM 457 LA, which was developed together with DDC for the special American market demands and which is produced and sold in the U.S.A. by DDC under the label “Series 55”, has had its premiere in Freightliner's Century Class, the OM 904 LA will now follow in the light commercial vehicle class. This engine has a completely new concept of a direct-injection, highly sophisticated turbocharged four-cylinder in-line engine with air-to-air intercooler, whose main characteristics can be outlined by the terms “multi-valve technology”, high-pressure injection via unit pumps” and “electronic engine control”. This “small” engine has several interesting features, which - up to now - were only known from class 8 engines.

The state of discussion on the new Euro III exhaust gas limits which have not been fixed yet and the test procedure will be presented. The development target at Mercedes-Benz is not only to reach the future limits reliably in standard production before they come into force but also to have the largest possible customer benefit, i. e. in particular favourable manufacturing costs and high fuel economy. An entirely new generation of engines is developed for this purpose. One essential point in this context is the injection system. Mercedes-Benz decided to develop new unit injection pumps with electronically actuated solenoid valves in conjunction with ordinary nozzle holders for high pressure levels, which feature advantages as compared to the known unit injector system. A common rail system providing further potential for a reduction in particulates constitutes an alternative.

The turbocharged and aftercooled types of the Deutz MWM diesel series 234 with 6, 8, 12 and 16 cylinders cover an output range of 313 to 900 kW (420 to 1 207 HP) for high speed marine propulsion. For this application the 234 engines are particularly suitable due to their high power density which is combined with low fuel consumption resulting in low volume and weight for the complete propulsion unit. On the basis of some design details the way of achieving these characteristics is described. Special measures were adopted to reach a high level of environmental compatibility and comfort. Several examples of engine installation in monohull and catamaran crafts are given.

Motoren-Werke Mannheim AG has designed a new series of in-line 4 stroke cycle Diesel engines with 2, 3, 4 and 6 cylinders in naturally aspirated and, except the 2-cylinder engine, turbocharged version. Although the new design would have allowed to increase the displacement, the 105 mm bore and the 120 mm stroke as well as the external dimensions of the previous series were maintained. The explanation of the reasons for this decision is followed by a description how the increase of the performance range was achieved without enlarging the displacement. This involves mainly the load capacity of the engine components required by higher degrees of turbocharging and improved cooling. As installation in agricultural tractors is a main application the capability of the engine structure to be loaded by increased external torsional and bending moments was also an important requirement.

Motoren-Werke Mannheim AG (MWM) has designed a new series of V-type engines incorporating 6, 8, 12 and 16 cylinders. By means of careful component optimization for higher firing pressures, to be explained on the basis of a few examples, it was possible to increase the standard vehicle output by 63 % and the maximum output available for special vehicles by 100 % while maintaining the external dimensions of the previous series. Consequently, the values achieved for output per volume as well as weight per HP make these engines suitable for many different uses in vehicles up to 1088 HP and a few examples will also be given. The low fuel consumption over the whole operating range is of particular importance in this connection.