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The environment load by traffic has reached limits of reasonableness in many places and metropoles. High mobility and environmental protection however can be equally fulfilled by consistently using latest automobile and engine technology. Nowadays the mean fuel consumption of new passenger cars equipped with gasoline engines is below 8 L/100 km and with diesel engines below 6 L/100 km. A 30 - 50 % reduction of fuel consumption within the next 10 years is expected with similar progress for commercial vehicle. This reduction of fuel consumption is not only important for saving resources, but also for protecting our global climate. The utmost target for engine development is to minimize both consumption and pollutant emissions. Effective reduction in classical pollutants for gasoline engines and new technologies such as oxydation Catalyst, De-NOx etc., for diesel engines have placed both power plants promising for passanger car market.

The paper describes the concept selection, design and performance of a fuel injection equipment (FIE) which provides high flexibility in shaping the injection rate. With this injection system standard and boot shaped injection rates as well as pilot injections and post injections can be achieved throughout the hole speed and load range. Special emphasis was drawn to realize boot rate shaping by pressure modulation rather than by throttling the fuel flow (i.e.: the system is operated with fully opened needle during the whole injection period and no throttling device limits the fuel flow in front of the nozzle to reduce the injection rate). Initial engine tests on a single cylinder research engine with 2 liter displacement were carried out at one operating point (1000 rpm, 200 mm3/str = 75% of full load fueling). Boot and pilot (split) injection rate shaping strategies are compared to a standard injection without rate shaping.

A number of commercially available and viable diesel fuels of different specifications was tested in two passenger cars powered by advanced prototype IDI and DI diesel engines, respectively, along the FTP 75, FTP 72 hot, the new European driving cycle [ECE 15 (urban) + EUDC (extra urban driving cycle)] cold and hot, and the Japan 10.15 driving cycle (hot start test). Both engines have been developed for emission levels currently required in Europe for diesel powered passenger cars. The results of this study demonstrate that fuel quality does have a significant impact on exhaust emissions of advanced diesel engines of both, DI and IDI combustion technology. The observed differences in emissions could be correlated with cetane number, density or aromatics content of the fuels tested whereas correlations with the distillation range (90% boiling point) was rather poor.

Stringent standards for the emission of particulate matter by heavy duty diesel engines will come into effect in the nineties in the US and are anticipated to come into effect in the same period in W-Europe and in Japan. This has lead most of the manufacturers to intensify the evaluation of exhaust aftertreatment devices. Although particulate filtering systems proved to be valuable in limited fleet applications, the general introduction did not take place because of complicated and limited durability regeneration. Flow-through catalysts which were introduced for passenger cars in 1989 drew a lot of attention for potential heavy duty diesel applications. In this paper the major parameters affecting the performance of these flow-through catalysts and the particularities related to heavy duty diesel application are outlined. The parameters deal with the fuel sulfur content, the test cycles applied, the catalyst formulation and washcoat composition.

The paper presents the current development status of direct injection diesel engines for passenger cars. Besides a description of the essential features of the injection and combustion system, reference is made to the performance and exhaust emissions potential of direct injection diesel engines in the light of legal requirements of both European Community countries and the U.S.A. Combustion noise and noise control are also discussed. The conclusion reached is that properly developed direct injection diesels will present a viable alternative to conventional passenger car power plants with the advantage of a substantially improved fuel economy.

In developing high speed swirl supported direct injection diesel engines it has been a general experience that different engine results (performance, smoke and emission) may be obtained when using different intake port designs, although the swirl numbers (stationary flow test rig) of the different ports were identical. Therefore, an in-cylinder flow investigation under motoring conditions using hot wire anemometry was performed for three different inlet port designs having the same swirl number. Special emphasis was drawn on the engine design parameters being as close as possible to reality. Thus, the flow investigation and the engine tests were carried out at a typical compression ratio of 18 : 1 using a standard combustion bowl in the piston as well as produceable inlet ports. All flow measurements were carried out under motoring conditions covering the speed range from 1100 to 2400 rpm.