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Multiple-injection strategies are widely used in DI diesel engines. However, the interaction of the injection pulses is not yet fully understood. In this work, a split injection into a combustion vessel is studied by multiple optical imaging diagnostics. The vessel provides quiescent high-temperature, high-pressure ambient conditions. A common-rail injector which is equipped with a three-hole nozzle is used. The spray is visualized by Mie scattering. First and second stage of ignition are probed by formaldehyde laser-induced fluorescence (LIF) and OH* chemiluminescence imaging, respectively. In addition formation of soot is characterized by both laser-induced incandescence (LII) and natural luminosity imaging, showing that low-sooting conditions are established. These qualitative diagnostics yield ensemble-averaged, two-dimensional, time-resolved distributions of the corresponding quantities.

The most challenging part of the engine combustion development is the reduction of pollutants (e.g. CO, THC, NOx, soot, etc.) and CO2 emissions. In order to achieve this goal, new combustion techniques are required, which enable a clean and efficient combustion. For compression ignition engines, combustion rate shaping, which manipulates the injected fuel mass to control the in-cylinder pressure trace and the combustion rate itself, turned out to be a promising opportunity. One possibility to enable this technology is the usage of specially developed rate shaping injectors, which can control the injection rate continuously. A feasible solution with series injectors is the usage of multiple injections to control the injection rate and, therefore, the combustion rate. For the control of the combustion profile, a detailed injector model is required for predicting the amount of injected fuel. Simplified 0D models can easily predict single injection rates with low deviation.

Exhaust aftertreatment systems must function sufficiently over the full useful life of a vehicle. In Europe this is currently defined as 160.000 km. With the introduction of Euro 7 it is expected that the required mileage will be extended to 240.000 km. This will then be consistent with the US legislation. In order to quantify the emission impact of exhaust system degradation, an Euro 7 exhaust aftertreatment system is aged by different accelerated approaches: application of the Standard Bench Cycle, the ZDAKW cycle, a novel ash loading method and borderline aging. The results depict the impact of oil ash on the oxygen storage capacity. For tailpipe emissions, the maximum peak temperatures are the dominant aging factor. The cold start performance is effected by both, thermal degradation and ash accumulation. An evaluation of this emission increase requires appropriate benchmarks.

In order to reduce development cost and time, frontloading is an established methodology for automotive development programs. With this approach, particular development tasks are shifted to earlier program phases. One prerequisite for this approach is the application of Hardware-in-the-Loop test setups. Hardware-in-the-Loop methodologies have already successfully been applied to conventional as well as electrified powertrains considering various driving scenarios. Regarding driving performance and energy demand, electrified powertrains are highly dependent on the dc-link voltage. However, there is a particular shortage of studies focusing on the verification of variable dc-link voltage controls by Hardware-in-the-Loop setups. This article is intended to be a first step towards closing this gap. Thereto, a Hardware-in-the-Loop setup of a battery electric vehicle is developed.

New 12 V/48 V power net architectures are potential solutions to close the gap between customer needs and legislative requirements. In order to exploit their potential, an increased effort is needed for functional implementation and hardware integration. Shifting of development tasks to earlier phases (frontloading) is a promising solution to streamline the development process and to increase the maturity level at early stages. This study shows the potential of the frontloading of development tasks by implementing a virtual 48 V mild hybridization in an engine-in-the-loop (EiL) setup. Advanced simulation technics like functional mock-up interface- (FMI) based co-simulation are utilized for the seamless integration of the real-time (RT) simulation models and allow a modular simulation framework as well as a decrease in development time.

Within a public founded project test cell investigations were undertaken to identify parameters which predominantly influence the development of critical deposits in injection nozzles. A medium-duty diesel engine was operated in two different coking cycles with a zinc-free lubricant. One of the cycles is dominated by rated power, while the second includes a wide area of the operation range. During the experiments the temperatures at the nozzle tip, the geometries of the nozzle orifice and fuel properties were varied. For a detailed analysis of the deposits methods of electron microscopy were deployed. In the course of the project optical access to all areas in the nozzle was achieved. The experiments were evaluated by means of the monitoring of power output and fuel flow at rated power. The usage of a SEM (scanning electron microscope) and a TEM (transmission electron microscope) revealed images of the deposits with a magnification of up to 160 000.

The use of state-of-the-art model-based calibration tools generate only limited benefits for seamless validation in powertrain calibration due to the often neglected system-level simulation of a closed-loop vehicle environment. This study presents a Hardware-in-the-Loop (HiL)-based virtual calibration approach to establish an accurate virtual calibration platform using physical plant models. It is based on a customisable real-time HiL simulation environment. The use of physical models to predict the behaviour of a complete powertrain makes the HiL test bench particularly suited for Engine Control Unit (ECU) calibration. With the virtual test rig approach, the calibration for the critical extended driving and ambient conditions of the new Real Driving Emissions (RDE) requirements can efficiently be optimised. This technique offers a clear advantage in terms of reducing calibration time and costs.

Over the last decades, the use of computers has become an integral part of the engine development process. Computer-based tools are increasingly used in the design process, and especially the layout of the various subsystems is conducted by means of simulation models. Computer-aided engineering plays a central role e.g. in the design of the combustion process as well as with regards to work performed in the area of engine mechanics, where CFD, FEM, and MBS are applied. As a parallel trend, it can be observed that various engine performance characteristics such as e.g. the specific power output and the power-to-weight ratio have undergone an enormous increase, a trend which to some extent counteracts the increase in safety against malfunction and failure. As yet, due to the constant need for further optimization, mechanical testing and verification processes have not become redundant, and it is assumed that they will remain indispensable for the foreseeable future.

In Common-Rail DI Diesel Engines, multiple injection strategies are considered as one of the methodologies to achieve optimum performance and emission reduction. However, multiple injections open a whole new horizon of parameters which affect the combustion process. These parameters include the number of injection events, the duration between the starts of each injection event, the splitting of the total fuel mass on the different injection events, etc. In the present work, the influence of the number of injection events and the influence of the duration between the starts of each injection event on emission levels are investigated. Combustion and pollutant formation were experimentally investigated in a Common-Rail DI Diesel engine. The engine was operated at conventional part-load conditions with 2000 rpm, no external EGR, and an injected fuel mass of 15 mg/cycle.

The droplet velocity is an important parameter for breakup, evaporation, and combustion of Diesel sprays, but it is very difficult to measure it by widely used laser diagnostic techniques like PDA, PIV and LCV under realistic high-pressure and high-temperature conditions. This is basically caused by laser beam steering and multiple scattering of light due to very high droplet densities, in particular close to the nozzle. It was demonstrated recently, that these problems can be greatly reduced by the laser flow tagging (LFT) technique. For this purpose, the model fuel is doped with a phosphorescent tracer. A number of droplet groups within the spray are tagged by illuminating them with focused beams of a pulsed laser, and their velocities are measured by recording the phosphorescence twice after each laser pulse using a double-frame ICCD.

The future worldwide emission regulations will request a drastic decrease of Diesel engine tailpipe emissions. Depending on the planned application and the real official regulations, a further strong decrease of engine out emissions is necessary, even though the utilized exhaust after-treatment systems are very powerful. To reduce NOx emissions internally, the external exhaust gas recirculation (EGR) is known as the most effective way. Due to the continuously increasing requirements regarding specific power, dynamic behavior and low emissions, future air path systems have to fulfill higher requirements and, consequently, become more and more complex, e.g. arrangements with a 2-stage turbo charging or 2-stage EGR system with different stages of cooling performance.

Calculating the bearing reliability and behavior is one of the primary tasks which have to be performed to define the main dimensions of the cranktrain of an internal combustion engine. Since the bearing results are essential for the pre-layout of the cranktrain, the conclusion on the bearing safety should be met as early as possible. Therefore detailed simulations like T-EHD or EHD analysis may not be applied to define the dimensions in such an early development phase. In the frame of this study a prediction methodology, based on a HD bearing approach, for bearing reliability of inline-4 crankshafts of passenger cars is proposed. In this way not only the design phase is shortened but also achieving the optimal solution is simplified. Moreover the requirement of a CAD model is eliminated for the preliminary design phase. The influencing parameters on the bearing behavior are first selected and divided into two groups: geometry and loading.

The modern engine development process is characterized by shorter development cycles and a reduced number of prototypes. However, simultaneously exhaust after-treatment and emission testing is becoming increasingly more sophisticated. It is expected that predictive simulation tools that encompass the entire powertrain can potentially improve the efficiency of the calibration process. The testing of an ECU using a HiL system requires a real-time model. Additionally, if the initial parameters of the ECU are to be defined and tested, the model has to be more accurate than is typical for ECU functional testing. It is possible to enhance the generalization capability of the simulation, with neuronal network sub-models embedded into the architecture of a physical model, while still maintaining real-time execution. This paper emphasizes the experimental investigation and physical modeling of the port fuel injected SI engine.

Technological progress opens the door for the development of new tools to be used for the development of vehicles and engines. This offers the opportunity for an optimization of the entire workflow on one hand, and an improvement of single tasks on the other hand. This paper describes the actual status of the development process, describes new directions of tool evolvement and finally gives an outlook into the future. Redline ADAPT-SIM is a tool for driver- and vehicle simulation, which was developed primarily for ECU application, but can also be used for other dynamic testing tasks. The introduction of this tool leads to better controllability and therefore also repeatability of tests.

Today, SULEV legislation represents the most stringent emission standard for vehicles with combustion engines, and it will be introduced starting by Model Year 2003. In order to meet such standards, even higher effort is required for the development of the exhaust gas emission concept of SI engines. Beyond a facelift of the combustion system, exhaust gas aftertreatment, and the engine management system, new approaches are striven for. The principle keys are well known: low HC feed gas, high thermal load for quick light-off, exhaust system with low heat capacity and highly effective exhaust gas aftertreatment.

The new Thermo-Elasto-Hydro-Dynamic (TEHD) code developed by FEV, is designed to improve the predictability of journal bearing designs and thereby increase the reliability of safety factors in the development of highly loaded internal combustion engines. Advanced analysis tools are evaluated by their performance as well as by their ease of use. High performance means on the one hand: taking into account all the important characteristics, like bearing elasticity or cavitation effects, to mention only some major parameters for modern journal bearing analysis. On the other hand: an economic run-time behavior must be a key feature concerning usability of the TEHD-demands for daily development praxis. Ease of use means also, that the TEHD model can easily be used as a plug-in routine of an already existing software package that is well known to the development departments.

Future HD Diesel engine technology is facing a combination of both extremely low exhaust emission standards (US 2002/2004, EURO IV and later US 2007, EURO V) and new engine test procedures such as the European Transient Cycle (ETC) in Europe and the Not-to-Exceed Area (NTE) in the US). Customers furthermore require increased engine performance, improved efficiency, and long-term durability. In order to achieve all targets simultaneously, future HD Diesel engines must have improved fuel injection and combustion systems and utilize suitable technologies such as exhaust gas recirculation (EGR), variable geometry turbine turbocharger systems (VGT) and exhaust gas after-treatment systems. Future systems require precision controlled EGR in combination with a VGT-turbocharger during transient operation. This will require new strategies and calibration for the Electronic Engine Control Unit (ECU).

This paper focuses on start-up technology for fuel processing systems with special emphasis on gasoline fueled burners. Initially two different fuel processing systems, an autothermal reformer with preferential oxidation and a steam reformer with membrane, are introduced and their possible starting strategies are discussed. Energy consumption for preheating up to light-off temperature and the start-up time is estimated. Subsequently electrical preheating is compared with start-up burners and the different types of heat generation are rated with respect to the requirements on start-up systems. Preheating power for fuel cell propulsion systems necessarily reaches up to the magnitude of the electrical fuel cell power output. A gasoline fueled burner with thermal combustion has been build-up, which covers the required preheating power.

Today, automated vehicles mostly rely on ego vehicle sensors such as cameras, radar or LiDAR sensors that are limited in their sensing capability and range. Vehicle-to-everything (V2X) communication has the potential to appropriately complement these sensors and even allow for a cooperative, proactive interaction of vehicles. As such, V2X communication might play a vital role on the way to smart and efficient traffic solutions. In the public funded research project UK Autodrive, we are currently investigating and experimentally evaluating V2X-based applications based on dedicated short range communication (DSRC). Moreover, the novel application intersection priority management (IPM) is part of the research project. IPM aims at automating intersections in such a way that vehicles can pass safely and even more efficiently without the use of traffic lights or signs.

This paper will present a multi-domain (electrical and thermal) model of a three phase voltage source converter and its implementation in Modelica language. An averaged model is utilised for the electrical domain, and a power balance method is used for linking the DC and AC sides. The thermal domain focuses in deriving the converter losses by deriving the analytical equations of the space vector modulation to derive a function for the duty cycle of each converter leg. With this, the conduction and switching losses are calculated for the individual switches and diodes, without having to model their actual switching behaviour. The model is very fast to simulate, as no switching events are needed, and allows obtaining the simulation of the electrical and thermal behaviour in the same simulation package..