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The Institute for Polymer Testing and Polymer Science (IKP) is an independent institute of the University of Stuttgart. For approximately 8 years work is done on the field of Life Cycle Engineering. The first couple of years knowledge about the production of materials was collected within plenty industrial cooperation. Parallel to this a methodology for the Life Cycle Engineering approach and a software system (GaBi 1.0-2.0) were developed. Based on these information, projects for balancing single parts like bumpers, fender, air intake manifolds and oil filters followed by projects handling more complex parts or processes like several body in white, headlights, fuel tanks, green tire or coating processes were done to establish the methodology of Life Cycle Engineering as a tool for decision makers and weak point analysis. Parallel to this a methodology for an Life Cycle Inventory (LCI) for the system automobile was developed in cooperation with the Volkswagen AG in 1993.

The NO formation is essentially determined by the flame temperature. In an engine the latter depends on the composition of the fuel and the intake gas. In this study the efficiency of various NO reducing measures is analysed by means of a comparison of measurements and computations for the Most frequent operation point of a 1.9 1 DI Diesel engine. The O2 concentration, which is shown to be the dominant source of influence on the flame temperature and NO formation, is varied using synthetic gas mixtures or by EGR. The molar heat capacity of CO2 and H2O in the recirculated exhaust gas, the intake temperature and the H/C ratio in the fuel are less important for the formation of NO. Measures which reduce the NO formation increase the ignition delay and thereby the fraction of the premixed combustion. The impact of EGR on the combustion process is illustrated by high speed filming.

During the combustion of an air-fuel mixture ions are produced by thermo, photo, and chemical ionization. The process of ion neutralization in heavy hydrocarbons and particles is considerably slower than in gas molecules. Only exhaust gas particles and atoms are expected to carry an electric charge. The ions flowing in the exhaust manifold can be detected by an ion probe. The induced charge at the ion probe can measure up to 50 pC and can be directly recorded on an oscillograph. The signals from two diesel engines (DI and IDI) and as a double check also a spark-ignition engine were picked up by an ion probe. In the case of the diesel engine the signals increased with the smoke emission. Signals from the spark-ignition engine have a different shape to those of a diesel engine.

A FUEL ECONOMY of 3,508 mpg was achieved at an average velocity of 10.5 mph with a specially-designed three-wheeled vehicle powered by a one-cylinder DI Diesel engine, the characteristics of which are as follows: