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The paper describes a zero-dimensional crank angle resolved combustion model which was developed for the analysis and prediction of combustion in compression ignition (CI) engines. The model relies on the multi zone combustion model (MZCM) approach of Hiroyasu. The main sub-models were taken from literature and extended with additional features described in this paper. A special procedure described in a previous paper is used to identify the mechanisms of the combustion process on the basis of the measured cylinder pressure trace. Based on the identified mechanisms the present work concentrates on the analysis of the causal effects that predominantly control the combustion process and the formation of NOx and Soot. The focus lies on the changes of the thermodynamic states and the composition of the reaction zones caused by different emission control strategies.

In order to meet the Euro V heavy-duty diesel emission standard legislation limits, a diesel engine can be optimized by internal means to give low particulate emissions and lower fuel consumption. These modifications of the engine lead inevitably to higher NOx emissions due to the NOx/PM trade off. An efficient Urea SCR after-treatment system is then able to reduce the higher NOx emission to below the Euro V 2.0g/kWh legislation limit. This paper presents tests made on a PM optimized 12 liter heavy-duty diesel engine together with a urea SCR after-treatment system. The optimized engine had engine out particulate emissions of about 0.04 g/kWh and NOx emissions of 9 g/kWh for the ESC and 8,5 g/kWh for the ETC. The fuel consumption of the optimized engine was 194 g/kWh for the ESC and 198 g/kWh for the ETC as compared to state of the art Euro III engines of typically 210 g/kWh for the ESC, giving significant fuel savings of 7.5 %.

This paper reports on research and development work conducted at AVL to determine the NOx-reduction potential of in-cylinder charge conditions, fuel injection system parameters, exhaust gas recirculation, fuel formulation, and exhaust gas aftertreatment by catalyst. Based on these findings, development options are derived and assigned to the various future emission standards in USA, Europe and Japan.

The paper reports on achievements obtained in an ongoing development program which is part of a european EUREKA joint research project named EFFLED (EFFicient Low Emission Diesel) being performed at AVL in cooperation with the companies DAF Trucks, Serck Heat Transfer, Robert Bosch and the Community of the City of Rotterdam. The main objective of this project is the development and refinement of a venturi supported exhaust gas recirculation (EGR) system for a turbocharged and intercooled heavy-duty (HD) diesel engine enabling map controlled cooled EGR rates which are high enough to achieve future low NOx emission standards at acceptable fuel consumption level. In addition to EGR, further technologies have been investigated, which may be required to meet future exhaust emission standards.

The influence of fuel density on exhaust emissions from diesel engines has been investigated in a number of studies and these have generally concluded that particulate emissions rise with increasing density This paper reviews recent work in this area, including the European Programme on Emissions, Fuels and Engine Technologies (EPEFE) and reports on a complementary study conducted by CONCAWE, in cooperation with AVL List GmbH The project was carried out with a passenger car equipped with an advanced technology high speed direct injection turbocharged / intercooled diesel engine fitted with a complex engine management system which was referenced to a specific fuel density This production model featured electronic diesel control, closed loop exhaust gas recirculation and an exhaust oxidation catalyst Tests were carried out with two EPEFE fuels which excluded the influence of key fuel properties other than density (828 8 and 855 1 kg/m3) Engine operation was adjusted for changes in fuel density by resetting the electronic programmable, read-only memory to obtain the same energy output from the two test fuels In chassis dynamometer tests over the ECE15 + EUDC test cycle the major impact of fuel density on particulate emissions for advanced engine technology/engine management systems was established A large proportion of the density effect on particulate and NOx emissions was due to physical interaction between fuel density and the electronic engine management system Limited bench engine testing of the basic engine showed that nearly complete compensation of the density effect on smoke (particulate) emissions could be achieved when no advanced technology was applied

Exhaust emission characteristics of a production automotive diesel engine were studied. The particular engine was chosen because it is being marketed with a prechamber as well as with a direct-injection combustion system and, in both configurations, either naturally aspirated or turbocharged. In addition, an aftercooler was fitted to the turbocharged direct-injection engine. Methods for reducing exhaust emissions are discussed. A brief survey is given of potential emission control by catalytic converter, exhaust recirculation, and LPG dual-fuel operation. Basic investigations, conducted on single-cylinder direct-injection (DI) engines are reported. It is concluded that direct injection is the most promising combustion system for low-emission commercial automotive diesel engines, particularly when turbocharged and aftercooled, and that this type of engine can satisfy the 1975 California standards.

The paper reports on the outcome of a still on-going joint-research project with the objective of establishing a demonstrator high speed direct injection (HSDI) diesel engine in a Sport Utility Vehicle (SUV) which allows to exploit the effectiveness of new engine and aftertreatment technologies for reducing exhaust emissions to future levels of US/EPA Tier 2 and Euro 4. This objective should be accomplished in three major steps: (1) reduce NOx by advanced engine technologies (cooled EGR, flexible high pressure common rail fuel injection system, adapted combustion system), (2) reduce particulates by the Continuous Regeneration Trap (CRT), and (3) reduce NOx further by a DeNOx aftertreatment technology. The current paper presents engine and vehicle results on step (1) and (2), and gives an outlook to step (3).