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The regulations for mobile applications will become stricter in Euro 6 and further emission levels and require the use of active aftertreatment methods for NOX and particulate matter. SCR and LNT have been both used commercially for mobile NOX removal. An alternative system is based on the combination of these two technologies. Developments of catalysts and whole systems as well as final vehicle demonstrations are discussed in this study. The small and full-size catalyst development experiments resulted in PtRh/LNT with optimized noble metal loadings and Cu-SCR catalyst having a high durability and ammonia adsorption capacity. For this study, an aftertreatment system consisting of LNT plus exhaust bypass, passive SCR and engine independent reductant supply by on-board exhaust fuel reforming was developed and investigated. The concept definition considers NOX conversion, CO2 drawback and system complexity.

Tighter emission limits are discussed and established around the world to improve quality of the air we breathe. In order to control global warming, authorities ask for lower CO2 emissions from combustion engines. Lots of efforts are done to reduce engine out emissions and/or reduce remaining by suitable after treatment systems. Watlow, among others, a manufacturer of high accurate, active temperature sensor ExactSense™, wanted to understand if temperature sensor accuracy can have an influence on fuel consumption (FC). For this purpose a numerical approach was chosen where several non-road driving cycles (NRTCs) were simulated with the data base of a typical Stage IV heavy duty diesel engine. The engine is equipped with an exhaust gas after treatment system consisting of a DOC, CDPF and an SCR. In this work scope, the investigations shall be restricted to the FC benefits obtained in the active and passive DPF regeneration.

Measures for reducing engine friction within the powertrain are assessed in this paper. The included measures work in combination with several new technologies such as new combustion technologies, downsizing and alternative fuels. The friction reduction measures are discussed for a typical gasoline vehicle. If powertrain friction could be eliminated completely, a reduction of 15% in CO2 emissions could be achieved. In order to comply with more demanding CO2 legislations, new technologies have to be considered to meet these targets. The additional cost for friction reduction measures are often lower than those of other new technologies. Therefore, these measures are worth following up in detail.

Fuel consumption and NOx emissions of gasoline engines at part load can be significantly reduced by Controlled Auto-Ignition combustion concepts. However, the range of Gasoline Controlled Auto-Ignition (GCAI) operation is still limited by lacking combustion stability at low load and by high pressure-rise rates toward higher loads. Previous investigations indicate that the auto-ignition process is particularly determined by the thermodynamic state of the charge and by stratification effects of residual gas, temperature, and air-fuel ratio. However, little experimental data exist on the direct influence of mixture stratification on local ignition and heat-release rate (HRR) in direct-injection (DI) GCAI engines, because it is challenging to measure all the relevant charge and combustion parameters quasi-simultaneously with sufficient spatial/temporal resolution and precision.

In the present paper, a recently developed centrifugal compressor model is briefly summarized. It provides a refined geometrical schematization of the device, especially of the impeller, starting from a reduced set of linear and angular dimensions. A geometrical module reproduces the 3D geometry of the impeller and furnishes the data employed to solve the 1D flow equations inside the rotating and stationary ducts constituting the complete device. The 1D compressor model allows to predict the performance maps (pressure ratio and efficiency) with good accuracy, once the tuning of a number of parameters is realized to characterize various flow losses and heat exchange. To overcome the limitations related to the model tuning, unknown parameters are selected with reference to 5 different devices employing an optimization procedure (modeFRONTIER™).

With the increasing popularity of seamless gear changing and smooth driving experience along with the need for high fuel efficiency, transmission system development has rapidly increased in complexity. So too has transmission control software while quality requirements are high and time-to-market is short. As a result, extensive testing and documentation along with quick and efficient development methods are required. FEV responds to these challenges by developing and integrating a transmission software product line with an automated verification and validation process according to the concept of Continuous Integration (CI). Hence, the following paper outlines a software architecture called “PERSIST” where complexity is reduced by a modular architecture approach. Additionally, modularity enables testability and tracking of quality defects to their root cause.

Model-based control strategies along with an adapted calibration process become more important in the overall vehicle development process. The main drivers for this development trend are increasing numbers of vehicle variants and more complex engine hardware, which is required to fulfill the more and more stringent emission legislation and fuel consumption norms. Upcoming fundamental changes in the homologation process with EU 6c, covering an extended range of different operational and ambient conditions, are suspected to intensify this trend. One main reason for the increased calibration effort is the use of various complex aftertreatment technologies amongst different vehicle applications, requiring numerous combustion modes. The different combustion modes range from heating strategies for active Diesel Particulate Filter (DPF) regeneration or early SCR light-off and rich combustion modes to purge the NOx storage catalyst (NSC) up to partially premixed combustion modes.

The aim of this research collaboration focuses on the realization of a novel Diesel combustion control strategy, known as Digital Combustion Rate Shaping (DiCoRS) for transient engine operation. Therefore, this paper presents an initial, 3D-CFD simulation based evaluation of a physical model-based feedforward controller, considered as a fundamental tool to apply real-time capable combustion rate shaping to a future engine test campaign. DiCoRS is a promising concept to improve noise, soot and HC/CO emissions in parallel, without generating drawbacks in NOx emission and combustion efficiency. Instead of controlling distinct combustion characteristics, DiCoRS aims at controlling the full combustion process and therefore represents the highest possible degree of freedom for combustion control. The manipulated variable is the full injection profile, generally consisting of multiple injection events.

A new approach is presented to modelling wall heat transfer in the exhaust port and manifold within 1D gas exchange simulation to ensure a precise calculation of thermal exhaust enthalpy. One of the principal characteristics of this approach is the partition of the exhaust process in a blow-down and a push-out phase. In addition to the split in two phases, the exhaust system is divided into several sections to consider changes in heat transfer characteristics downstream the exhaust valves. Principally, the convective heat transfer is described by the characteristic numbers of Nusselt, Reynolds and Prandtl. However, the phase individual correlation coefficients are derived from 3D CFD investigations of the flow in the exhaust system combined with Low-Re turbulence modelling. Furthermore, heat losses on the valve and the seat ring surfaces are considered by an empirical model approach.

Reducing fuel consumption is a major challenge for vehicle, especially for SUV. Cooling loss is about 30% in total energy loss under NEDC (New European Driving Cycle) cycle. It is necessary to optimize vehicle thermal management system to improve fuel economy. Otherwise, rapid warm-up is beneficial for friction reduction and passenger comfort in cold-start. Vehicle thermal behavior is influenced by cooling system layout, new technology and control strategy. Thermal management simulation is effective to show the energy flow and fuel consumption under the influence of new technology under NEDC cycle. So 1D thermal management simulation model is created, including vehicle, cooling system, lubrication system and detailed engine model with all friction components. And the interrelations between all the components are considered in the model. For model calibration, large amount of data is obtained from vehicle tests such as transient fuel consumption and transient coolant temperature.

This study investigated dual-fuel operation with a light duty Diesel engine over a wide engine load range. Ethanol was hereby injected into the intake duct, while Diesel was injected directly into the cylinder. At low loads, high ethanol shares are critical in terms of combustion stability and emissions of unburnt hydrocarbons. As the load increases, the rates of heat release become problematic with regard to noise and mechanical stress. At higher loads, an advanced injection of Diesel was found to be beneficial in terms of combustion noise and emissions. For all tests, engine-out NOx emissions were kept within the EU-6.1 limit.

Crankshaft is a dynamic component that copes with elevated alternating stresses. In order to ensure the service reliability, fillet rolling process is being applied. The state of the art empirical assumptions to consider the effect of fillet rolling process on crankshaft fatigue are conservative. This leads to an over-engineering of the crankshaft. However, calculation of the compressive residual stresses due to surface treatment is a demanding task. The quality of the durability analysis can only be increased by an accurate consideration of the fillet rolling effect. Therefore, Hegenscheidt-MFD, FEV Motorentechnik and Institute for Combustion Engines (VKA) cooperated to enlighten the phenomenon of the fillet rolling process. Process calculations are applied and validated by the measurements and tests. The calculated residual stresses are then superposed with the dynamic loads calculated by FEV Virtual Engine.

During a thermal regeneration of a Diesel particulate filter (DPF) the temperature inside the DPF may raise above critical thresholds in an uncontrolled way (thermal shock). Especially driving conditions with a comparable low exhaust gas mass flow and high oxygen content like idle speed may create a thermal shock. This paper presents a concept for an ECU software structure to prevent the DPF from reaching improper temperatures and the methodology in order to calibrate this ECU structure. The concept deals in general with a closed-loop control of the exhaust gas air-fuel-ratio during the critical engine operation phases. Those critical operation phases are identified at the engine test bench during “Drop-to-Idle” and “Drop-to-Overrun” experiments. The experiments show that those phases are critical having on the one hand a low exhaust gas mass flow and on the other hand a high oxygen percentage in the exhaust gas.

Demand for transport energy is growing but this growth is skewed heavily toward commercial transport, such as, heavy road, aviation, marine and rail which uses heavier fuels like diesel and kerosene. This is likely to lead to an abundance and easy availability of lighter fractions like naphtha, which is the product of the initial distillation of crude oil. Naphtha will also require lower energy to produce and hence will have a lower CO₂ impact compared to diesel or gasoline. It would be desirable to develop engine combustion systems that could run on naphtha. Many recent studies have shown that running compression ignition engines on very low Cetane fuels, which are very similar to naphtha in their auto-ignition behavior, offers the prospect of developing very efficient, clean, simple and cheap engine combustion systems. Significant development work would be required before such systems could power practical vehicles.

Sustainable and energy-efficient consumption is a main concern in contemporary society. Driven by more stringent international requirements, automobile manufacturers have shifted the focus of development into new technologies such as Hybrid Electric Vehicles (HEVs). These powertrains offer significant improvements in the efficiency of the propulsion system compared to conventional vehicles, but they also lead to higher complexities in the design process and in the control strategy. In order to obtain an optimum powertrain configuration, each component has to be laid out considering the best powertrain efficiency. With such a perspective, a simulation study was performed for the purpose of minimizing well-to-wheel CO2 emissions of a city car through electrification. Three different innovative systems, a Series Hybrid Electric Vehicle (SHEV), a Mixed Hybrid Electric Vehicle (MHEV) and a Battery Electric Vehicle (BEV) were compared to a conventional one.

The automotive industry continues to develop new powertrain technologies aimed at reducing overall vehicle level fuel consumption. The ongoing trends of “downsizing” and “down speeding” have led to the development of turbocharged engines with low displacement and high torque density. In order to meet the launch response requirements with these engines as well as fuel economy needs, transmissions with large ratio spreads will need to be developed. Due to the lack of torque amplification from the torque converter, the next generation of dual clutch transmissions (DCT) will need to have larger launch ratios and ratio spreads than currently available in production today. This paper discusses the development of a new family of DCT (called “xDCT”) for use in front wheel drive vehicles, aimed at meeting some of these challenges. The xDCT family features two innovative concepts, the idea of “gear generation” and “supported shifts”.

To comply with the new regulations on particulate matter emissions, the manufacturers of light-duty as well as heavy-duty vehicles more commonly use diesel particulate filters (DPF). The regeneration of DPF depends to a significant extent on the properties of the soot stored. Within the Cluster of Excellence "Tailor-Made Fuels from Biomass (TMFB)" at RWTH Aachen University, the Institute for Combustion Engines carried out a detailed investigation program to explore the potential of future biofuel candidates for optimized combustion systems. The experiments for particulate measurements and analysis were conducted on a EURO 6-compliant High Efficiency Diesel Combustion System (HECS) with petroleum-based diesel fuel as reference and a today's commercial biofuel (i.e., FAME) as well as a potential future biomass-derived fuel candidate (i.e., 2-MTHF/DBE). Thermo gravimetric analyzer (TGA) was used in this study to evaluate the oxidative reactivity of the soot.

The limited availability of fossil fuels and the increasing environmental pollution will lead to an increased demand for sustainable biofuels. The production of bio-based diesel fuels from vegetable oils is commonly accomplished using a process known as Trans-esterification. The product of Transesterification is Fatty Acid Methyl Ester (FAME), commonly known as Biodiesel. An alternative process is Hydro-treatment of seed oils or animal waste fats to produce highly paraffinic renewable diesel fuel called Hydrogenated Vegetable Oil (HVO). Detailed investigations were carried out by the “Department of Advanced Diesel Engine Development” at FEV GmbH Aachen (Germany), to explore the potential of this biofuel compound as a candidate for future compression ignition engines.

This work is a continuation of earlier results presented by the authors. In the current investigations the biofuels hydrogenated vegetable oil (HVO) and 1-octanol are investigated as pure components and compared to EN 590 Diesel. In a final step both biofuels are blended together in an appropriate ratio to tailor the fuels properties in order to obtain an optimal fuel for a clean combustion. The results of pure HVO indicate a significant reduction in CO-, HC- and combustion noise emissions at constant NOX levels. With regard to soot emissions, at higher part loads, the aromatic free, paraffinic composition of HVO showed a significant reduction compared to EN 590 petroleum Diesel fuel. But at lower loads the high cetane number leads to shorter ignition delays and therefore, ignition under richer conditions.

The range of tasks in automotive electrical system development has clearly grown and now includes goals such as achieving efficiency requirements and complying with continuously reducing CO2 limits. Improvements in the vehicle electrical system, hereinafter referred to as the power net, are mandatory to face the challenges of increasing electrical energy consumption, new comfort and assistance functions, and further electrification. Novel power net topologies with dual batteries and dual voltages promise a significant increase in efficiency with moderate technological and financial effort. Depending on the vehicle segment, either an extension of established 12 V micro-hybrid technologies or 48 V mild hybridization is possible. Both technologies have the potential to reduce fuel consumption by implementing advanced stop/start and sailing functionalities.