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Hybrid vehicles are characterized by a combination of mechanical, electrical and control components. The complexity of this mechatronic system requires new methods and tools for a successful development of new hybrid vehicle concepts. It is now possible to accomplish certain tasks earlier in the development projects using virtual prototypes of the powertrain components and the vehicle. The process called “frontloading” integrates simulation, optimization and validation in earlier development phases of a vehicle and prevents from having cost intense problems in later development phases. Besides the reduction of emissions and fuel consumption also the subjective impression of the vehicle driveability are main goals for the optimization of hybrid powertrains.

The paper reports on a study performed as a joint project between Rhodia, Renault Automobiles and AVL and deals with the application of a sintered metal trap (SMT) whose regeneration is supported by the use of a Ce-based fuel-borne catalyst installed on a delivery van equipped with a conventional IDI/NA diesel engine. For demonstration purpose, a trap protection strategy was developed with the aim to minimize the trap loading and thus the consequent fuel consumption penalty that can be observed for worst-case low speed driving scenarios. Measures to temporarily increase the exhaust gas temperature during inner-city driving and therefore to initiate the start of regeneration were successfully applied. MAJOR EFFORT IS BEING currently undertaken to develop and apply advanced aftertreatment systems to meet future proposed exhaust gas emission standards for passenger cars, LDT and HD diesel engines.

The prosperity of modern society is unthinkable without technology. One of the most important technical products so far is undoubtedly the automobile. It has been used by man to satisfy his deeprooted desire for freedom, independence and mobility. 500 million motor vehicles on the roads across the world are clear evidence of the fact that society no longer wants to forego the benefit of the automobile. According to the forecasts of several experts, the car population may reach 1.3 billion by the middle of the next century - if the markets keep developing as expected. This enormous growth rate places an obligation on engineers in the automobile industry to do everything to further improve the automobile. Above all, this demands an additional deduction of fuel consumption as well as efforts to keep negative impact on the environment to a minimum. Modern high speed direct injection diesel engines distinguish themselves from other internal combustion engines through their high efficiency.

In a fast and cost-efficient powertrain development process several optimization and validation tasks are required at early development stages, where prototype vehicles are not available. Especially for hybrid powertrain concepts the development targets for fuel consumption, vehicle performance, functional safety and durability have to be validated on the engine test bed before integration and testing with real vehicle prototypes takes place. The integration of relevant control unit functions like transmission shift or vehicle stability as AUTOSAR software component into a simulation system at the engine test bed allows a fast and integrated workflow for series development. Complementary a high-quality combustion torque estimation and the consideration of driver behavior and lateral vehicle dynamics improve the correlation of simulated to real world driving maneuvers.

Diesel engines belong to the most efficient power sources for any kind of on-road vehicle, but especially in Europe increasingly for passenger cars. However, more stringent exhaust emission regulations, which will come into force world-wide in industrialised countries during the first decade of the next century will require NOx and particulate emissions to be reduced by up to 60% and more from today's levels. To meet these future emission standards particularly for heavier passenger vehicles, such as SUVs, Pickup Trucks and Light Commercial Vehicles, as well as for heavy luxury class passenger cars, the application of new technologies including advanced exhaust gas aftertreatment systems will be indispensable, especially in view of maintaining the thermal efficiency of diesel engines relative to gasoline engines.

After a review of current and future emission legislation for non-road engines (India, Europe, USA), the various options available to reduce the emissions of diesel tractor engines are discussed. Special emphasis is put on naturally aspirated engines in the 37 - 50 kW power range. AVL has recently designed and developed several naturally aspirated heavy-duty diesel tractor engines to comply with current exhaust emissions standards for the Indian domestic and the US markets (EPA Tier 2). In doing so, different levels of technologies were applied. Their impact on mean effective pressure, specific fuel consumption and emissions will be shown. The future non-road engine exhaust emissions legislation in different markets will be addressed (India, Europe and USA). Compliance with the new emission standards will require the introduction of more advanced technology.

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.

Emission legislation and the transient test cycle issues are addressed to show the focus of future emission development. Strategic options to meet the Euro-IV emission standard are given, and the most important base engine and exhaust aftertreatment technologies required for emission compliance are discussed. Results shown from AVL R&D work indicate the potential of further emission reductions as will be required beyond Euro-IV.

Modern day diesel engines use systems like Exhaust Gas Recirculation (EGR), Variable Geometric Turbo Charger (VGT), inlet throttle for air regulation, multiple injection strategies, high pressure rail systems for fuel regulation to optimize the combustion for meeting the strict emission and fuel consumption demands. Torque based ECU structures which are commonly used for diesel engines require a large amount of calibration work. Conventional manual methods for emission and fuel consumption optimization (Full factorial or Line search method) results in increased test bed usage and it is almost impossible to use these methods as the number of parameters to optimize are very high. The conventional DoE tests have been limited by the necessity of calibration engineer’s expertise and manual prescreening of test points to be within thermal & mechanical limits of engine systems. This subsequently leads to excessive screening of variables; which is time consuming.