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The HSDI Diesel engine contributes substantially to the decrease of fleet fuel consumption thus to the reduction of CO2 emissions. This results in the rising market acceptance which is supported by desirable driving performance as well as greatly improved NVH behavior. In addition to the above mentioned requirements on driving performance, fuel economy and NVH behavior, continuously increasing demands on emissions performance have to be met. From today's view the Diesel particulate trap presents a safe technology to achieve the required reduction of the particle emission of more than 95%. However, according to today's knowledge a further, substantial NOx engine-out emission reduction for the Diesel engine is counteracts with the other goal of reduced fuel consumption. To comply with current and future emission standards, Diesel engines will require DeNOx technologies.

Due to the contradiction of the market demands and legal issues OEMs are forced to invest in finding concepts that assure high fuel economy, low exhaust emissions and high specific power at the same time. Since mechanical losses may amount up to 10 % of the fuel energy, a key to realise such customer/government specific demands is the improvement of the mechanical performance of the engines, which comprises mainly friction decrease and lightweight design of the engine parts. In order to achieve the mentioned objectives, it has to be checked carefully for each component whether the design potentials are utilized. Many experimental studies show that there is still room for optimization of the cranktrain parts, especially for the crankshaft. A total exploitation of the crankshaft potentials is only possible with advanced calculation approaches that ensure the component layout within design limits.

Since the CO2 emissions of passenger car traffic and their greenhouse potential are in the public interest, natural gas (CNG) is discussed as an attractive alternative fuel. The engine concepts that have been applied to date are mainly based upon common gasoline engine technology. In addition, in mono-fuel applications, it is made use of an increased compression ratio -thanks to the RON (Research Octane Number) potential of CNG-, which allows for thermodynamic benefits. This paper presents advanced engine concepts that make further use of the potentials linked to CNG. Above all, the improved knock tolerance, which can be particularly utilized in turbocharged engine concepts. For bi-fuel (CNG/gasoline) power trains, the realization of variable compression ratio is of special interest. Moreover, lean burn technology is a perfect match for CNG engines. Fuel economy and emission level are evaluated basing on test bench and vehicle investigations.

The DEXA Cluster consisted of three closely interlinked projects. In 2003 the DEXA Cluster concluded by demonstrating the successful development of critical technologies for Diesel exhaust particulate after-treatment, without adverse effects on NOx emissions and maintaining the fuel economy advantages of the Diesel engine well beyond the EURO IV (2000) emission standards horizon. In the present paper the most important results of the DEXA Cluster projects in the demonstration of advanced particulate control technologies, the development of a simulation toolkit for the design of diesel exhaust after-treatment systems and the development of novel particulate characterization methodologies, are presented. The motivation for the DEXA Cluster research was to increase the market competitiveness of diesel engine powertrains for passenger cars worldwide, and to accelerate the adoption of particulate control technology.

Electromechanical valve trains in camless engines enable virtually fully variable valve timing that offers large potential for both part load fuel economy and high low end torque. Based upon the principle of a spring-mass-oscillator, the actuator stores the energy to open and close the valves in springs. However, the motion of the valves and the electromechanical actuation suffers from parasitic losses, such as friction and ohmic resistance. Besides eddy current losses, gas forces obviously play a further important role in the control of exhaust valve opening especially at high engine speeds and loads. Based on engine test bench data, computational simulations (3D CFD, gas exchange process and electromechanical system) are carried out to analyze the effects of exhaust valve gas forces on the dynamic motion of valve and actuator. The modeling approach and results of this investigation are discussed in this paper.

Future boundary conditions for vehicle engine development will be very complex since they are “functions” of parameters that are difficult to predict: increasingly stringent legislation, changing consumer demand, and availability of resources. The main development goals for passenger cars today are the enhancement of performance and reduction of fuel consumption and cost while facing future emission standards. In China for example, drastic changes in emission regulation have forced the automotive industry to speed up the development processes and shorten the product life cycles. In this respect, the Mianyang Xinchen Engine Co. Ltd, part of Brilliance Group, Mianyang China and FEV Motorentechnik, Aachen Germany conducted a joint project to study Mianyang's 2.2L, 2-valve, multipoint fuel injection (MPI) gasoline engine.

The challenge to reduce fuel consumption in S.I. engines is leading to the application of new series production technologies: including direct injection and, recently, the variable valve train, both aiming at unthrottled engine operation. In addition to these technologies, turbo- or mechanical supercharging is of increasing interest because, in principle, it offers a significant potential for improved fuel economy. However, a fixed compression ratio normally leads to a compromise, in that the charged engine is more of a performance enhancement than an improver of fuel economy. Fuel efficient downsizing concepts can be realized through the application of variable compression ratio. In this paper, a variable compression ratio design solution featuring eccentric movement of the crankshaft is described. Special attention is given to the integration of this solution into the base engine.

Due to increasing demand for environment friendly vehicles with better fuel economy and strict legislations on greenhouse gas emissions, lightweight design has become one of the most important issues concerning the automobile industry. Within the scope of this work lightweight design potentials that a conventional single cylinder engine crankshaft offers are researched through utilization of structural optimization techniques. The objective of the study is to reduce mass and moment of inertia of the crankshaft with the least possible effect on the stiffness and strength. For precise definition of boundary conditions and loading scenarios multi body simulations are integrated into the optimization process. The loading conditions are updated at the beginning of each optimization loop, in which a multi body simulation of the output structure from the previous optimization loop is carried out.

Both, the continuous strengthening of the exhaust emission legislation and the striving for a substantial reduction of carbon dioxide output in the traffic sector depict substantial requirements for the development of future diesel engines. These engines will comprise not only the mandatory diesel oxidation catalyst (DOC) and particulate filter DPF but a NOx aftertreatment system as well - at least for heavier vehicles. The oxidation catalysts as well as currently available NOx aftertreatment technologies, i.e., LNT and SCR, rely on sufficient exhaust gas temperatures to achieve a proper conversion. This is getting more and more critical due to the fact that today's and future measures for CO₂ reduction will result in further decrease of engine-out temperatures. Additionally this development has to be considered in the light of further engine electrification and hybridization scenarios.

Both, the continuous strengthening of the exhaust emission legislation and the striving for a substantial reduction of the carbon dioxide output in the traffic sector depict substantial requirements for the global automotive industry and especially for the engine manufacturers. From the multiplicity of possible approaches and strategies for clear compliance with these demands, engine internal measures offer a large and, eventually more important, very economical potential. For example, the achievements in fuel injection technology are a measure which in the last years has contributed significantly to a notable reduction of the emissions of the modern DI Diesel engines at favorable fuel efficiency. Besides the application of modern fuel injection technology, the linked combustion control (Closed Loop Combustion Control) opens possibilities for a further optimization of the combustion process.

In view of limited crude oil resources, alternative fuels for internal combustion engines are currently being intensively researched. Synthetic fuels from natural gas offer a promising interim option before the development of CO2-neutral fuels. Up to a certain degree, these fuels can be tailored to the demands of modern engines, thus allowing a concurrent optimization of both the engine and the fuel. This paper summarizes investigations of a Gas-To-Liquid (GTL) diesel fuel in a modern, post-EURO 4 compliant diesel engine. The focus of the investigations was on power output, emissions performance and fuel economy, as well as acoustic performance, in comparison to a commercial EU diesel fuel. The engine investigations were accompanied by injection laboratory studies in order to assist in the performance analyses.

Potential improvements in spark ignited engine performance gained through the application of ceramic valve train components were predicted using state-of-the-art valve train simulation and gas exchange computer programs. The use of ceramic valves, ceramic pushrods, and ceramic hydraulic tappet housings, in combination with modified valve spring and valve lift parameters, were analyzed for a 2.8L overhead valve V-6 engine. The results show that significant improvements in dynamic valve train behavior and engine performance are possible with the largest gains coming from the use of ceramic valves. Potential improvements in valve train dynamics include: a 20% increase in maximum engine speed; a 30% reduction in the maximum valve train forces; and a 30% reduction in valve train friction. These benefits can then be used to either improve fuel economy, high speed engine power or low speed torque by up to 5%.

With rising gasoline prices in the US the need for increasingly fuel efficient powertrain concepts has never been more critical. Evaluation of the market on the other hand shows that the vehicle-buying consumer is unwilling to compromise engine power output for this needed fuel efficiency. Boosted, direct-injected gasoline engines with high specific output and low end torque seem to be the most logical path to satisfying both good part load fuel economy and generous power and torque characteristics. Turbo lag and subsequent lack of torque during transient acceleration (with low initial engine speeds) are characteristics of current turbocharged gasoline engines. These phenomena have prevented successful penetration of these boosted powertrains into the marketplace. Larger displacement, naturally aspirated gasoline engines have been the preferred choice.

The current discussion about possible limitation of CO2 emissions makes improvement of fuel consumption a central topic for gasoline engine development. Various technological solutions are available to realize this improvement. Concepts featuring direct fuel injection, engine downsizing and unthrottled control of engine load with variable valvetrains are currently considered the most promising ways to achieve this goal. Further concepts that are under development include Controlled Auto Ignition (CAI) and homogenous lean burn combustion as well as certain combinations of these technologies. Within the European market, direct injection is currently the most popular solution. The drawback is that a very expensive exhaust gas aftertreatment system is necessary to keep exhaust emissions within legal limits.

Passenger cars with diesel engines have better fuel economy than cars with gasoline engines. Also diesel engines typically have lower HC and CO emissions than all but the very best, state-of-the-art gasoline engines. On the other hand, diesel NOx and particulate emissions are higher, but recent developments have significantly reduced diesel particulate emissions. While the regulated emissions from both engines are well known, there are relatively few data on the non-regulated emissions for modern diesel engines.

The NVH optimization is a key issue for the development of future powertrains. This includes the radiated noise in terms of noise level and sound quality as well as the structure-borne noise excitation via the engine mounts. Experience shows that there are generally no single noise relevant components on modern powertrains which dominate the NVH behaviour. In contrast, a good NVH performance can only be achieved if the optimization process includes every single component and excitation. Only the combination of these optimized designs can lead to a first-class powertrain NVH. Within this paper the NVH optimization process of an existing 4-cylinder in-line spark-ignition powertrain is described. Examples for positive NVH designs are presented and their effect on the NVH behaviour are explained. Combining all positive NVH features into the engine resulted in a noise reduction of 3-5 dBA without any negative effect on fuel economy and performance.

The development of new passenger car powertrains with gasoline direct injection engines is facing new requirements which result from the need of different operational modes with stratified and homogeneous air fuel mixture. Moreover, the exhaust aftertreatment system causes a discontinuous operation with lean burn adsorption periods followed by short rich spikes for catalyst regeneration. Recent work on combustion system development has shown, that gasoline direct injection can create significant fuel economy benefits. Charge motion controlled combustion systems have proven to be of advantage in terms of low raw emissions compared to wall guided concepts. Based on an initial single-cylinder development phase a multi-cylinder engine was realized with excellent fuel economy, low raw emissions and operational robustness. Finally, the new engine's potential has been demonstrated in a mid-class vehicle.

The development of new passenger car powertrains with gasoline direct- injection engines is facing new requirements which result from the need of different operational modes with stratified and homogeneous air-fuel mixture. Moreover, the exhaust aftertreatment system causes a discontinuous operation with lean-burn absorption periods followed by short rich spikes for catalyst regeneration. Recent work on combustion system development has shown, that gasoline direct injection can create significant fuel economy benefits. Charge motion controlled combustion systems have proven to be of advantage in terms of low raw emissions compared to wall-guided concepts. Based on an initial single-cylinder development phase, a multi-cylinder engine was realized with excellent fuel economy, low raw emissions and operational robustness. Finally, the new engine''s potential has been demonstrated in a mid-class vehicle.

The fuel consumption and the emissions of modern passenger cars are highly affected by the fluid and material temperatures of the engine. Unfortunately, the high thermal efficiencies of Direct Injection (DI) Diesel and Spark Ignition (SI) engines cause in many driving situations low heat transfer to the engine components and especially to the oil and the coolant. In these conditions the normal operating temperatures are not achieved. Especially at low ambient temperatures and low engine loads the requirement of a comfortable cabin heating and a fast warm-up of engine oil and coolant cannot be satisfied simultaneously. To reach the required warm-up performance, an Exhaust Heat Recovery System (EHRS) will be demonstrated. Further design and optimization processes for modern cooling systems in fuel-efficient engines require numerical and experimental investigations of supplemental heater systems to meet all requirements under all circumstances.