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The hydrogen engine is one of the promising technologies that enables carbon-neutral mobility, especially in heavy-duty on- or off-road applications. In this paper, a methodological procedure for the design of the combustion system of a hydrogen-fueled, direct injection spark ignited commercial vehicle engine is described. In a preliminary step, the ability of the commercial 3D computational fluid dynamics (CFD) code AVL FIRE classic to reproduce the characteristics of the gas jet, introduced into a quiescent environment by a dedicated H2 injector, is established. This is based on two parts: Temporal and numerical discretization sensitivity analyses ensure that the spatial and temporal resolution of the simulations is adequate, and comparisons to a comprehensive set of experiments demonstrate the accuracy of the simulations. The measurements used for this purpose rely on the well-known schlieren technique and use helium as a safe substitute for H2.

This study focuses on evaluation of various fuels within a conventional gasoline internal combustion engine (ICE) vehicle and the implementation of advanced emissions reduction technology. It shows the robustness of the implemented technology packages for achieving ultra-low tailpipe emissions to different market fuels and demonstrates the potential of future GHG neutral powertrains enabled by drop-in lower carbon fuels (LCF). An ultra-low emission (ULE) sedan vehicle was set up using state-of-the-art engine technology, with advanced vehicle control and exhaust gas aftertreatment system including a prototype rapid catalyst heating (RCH) unit. Currently regulated criteria pollutant emission species were measured at both engine-out and tailpipe locations. Vehicle was run on three different drive cycles at the chassis dynamometer: two standard cycles (WLTC and TfL) at 20°C, and a real driving emission (RDE) cycle at -7°C.

In the context of the energy transition, CO2-neutral solutions are of enormous importance for all sectors, but especially for the mobility sector. Hydrogen as an energy carrier has therefore been the focus of research and development for some time. However, the development of hydrogen combustion engines is in many respects still in the conception phase. Automotive system providers and engineering companies in the field of software development and simulation are showing great interest in the topic. In a joint project with the industrial partners Robert Bosch GmbH and AVL Germany, combustion in a H2-DI-engine for use in light-duty vehicles was methodically investigated using the CFD tool AVL FIRE®. The collaboration between Robert Bosch GmbH and the Institute for Mobile Systems (IMS) at Otto von Guericke University Magdeburg has produced a model study in which model approaches for the combustion of hydrogen can be analyzed.

In the future, conventional powertrains will increasingly be supplied by sustainable energy sources. Long-haul freight transport requires efficient energy storage and the ability to refuel quickly. For this reason, hydrogen-powered PEM fuel cells are being discussed as a future energy source for long-distance vehicles. However, there are numerous challenges in packaging, system cooling and service life. Above all, the dissipation of the fuel cell’s heat losses places high demands on the design of the cooling system due to the relatively low operating temperature. In the presented study, a complete generic drive train of a long-distance commercial vehicle was set up within a suitable simulation environment to investigate the required sizes of the fuel cell stack, the HV battery, the hydrogen tanks, and the cooling circuit.

X-Domain describes the merging of different domains (i.e., braking, steering, propulsion, suspension) into single functionalities. One example in this context is torque-vectoring. Different goals can be pursued by applying X-Domain features. On the one hand, savings in fuel consumption and an improved vehicle driving performance can be potentially accomplished. On the other hand, safety can be improved by taking over a failed or degraded functionality of one domain by other domains. The safety-aspect from the viewpoint of requirements is highlighted within this contribution. Every automotive system being developed and influencing the vehicle safety must fulfill certain safety objectives. These are top-level safety requirements (ISO 26262-1) specifying functionalities to avoid unreasonable risk. Every safety objective is associated with an Automotive Safety Integrity Level (ASIL) derived from a Hazard Analysis and Risk Assessment (HARA).

Historically, whenever the automotive solutions’ state of art reaches a saturation level, the integration of new verticals of technology has always raised new opportunities to innovate, enhance and optimize automotive solutions. The predictive powertrain solutions using connectivity elements (e.g., navigation unit, e-Horizon or cloud-based services) are one of such areas of huge interest in automotive industry. The prior knowledge of trip destination and its route characteristics has potential to make prediction of powertrain modes or events in certain order and therefore it can add value in various application areas such as optimized energy management, lower fuel consumption, superior safety and comfort, etc.

Today unmanned aerial vehicle applications are powered by Wankel rotary engines due to their high power-to-weight ratio and smooth operation. Most of modern propulsion units for unmanned aerial vehicles are designed to run on high volatile fuels such as aviation gasoline (AvGas). However, the refueling infrastructure in aviation is geared toward the most used aviation fuel, kerosene. This and other reasons, such as significantly lower price and easier fire protection regulations, lead to the desire to be able to operate these propulsion units with kerosene. Opposed to reciprocating engines, the low compression ratio of rotary engines prevents the implementation of compression ignition combustion processes. Therefore, the purpose of this paper is to discuss the operation of a spark-ignited rotary engine on different fuels. In detail, different qualities of kerosene as well as gasoline/kerosene blends are compared together.

The overall efficiency of hybrid electric vehicles largely depends on the design and application of its energy management system (EMS). Despite the load coordination when operating the system in a hybrid mode, the EMS accounts for state changes between the different driving modes. Whether a transition between pure electric driving and internal combustion engine (ICE) powered driving is beneficial depends, among others, on the respective operation point, the route ahead as well as on the energetic expense for the engine start itself. The latter results from a complex interaction of the powertrain components and has a tremendous impact on the efficiency and quality of EMSs. Optimization based methods such as dynamic programming serve as benchmark for the design process of rule based control strategies. In case no energetic expenses are assigned to a state change, the resulting EMS suffers from being sub-optimal regarding the fuel consumption.

The efficiency of a Hybrid Electric Vehicle (HEV) strongly depends on its implemented Energy Management Strategy (EMS) that splits the driver’s torque request onto the Internal Combustion Engine (ICE) and Electric Motor (EM). For calibrating these EMS, usually, steady-state efficiency maps of the power converters are used. These charts are mainly derived from measurements under optimal conditions. However, the efficiency of ICEs fluctuates strongly under different conditions. Among others, these fluctuations can be induced by charge air temperature, engine oil temperature or the fuel’s knock resistance. This paper proposes a new approach for predicting the impact of any external influence onto the ICE efficiency. This is done by computing the actual deviation from the optimal reference ignition timing and adjusting the result by actual oil temperature and target air-to-fuel ratio.

The usage of ethanol and two different mixtures of ethanol and gasoline (E85 and E65) wаs investigated on a modified diesel engine designed to work in a dual-fuel combustion mode with intake manifold alcohol injection. The maximum ratio of alcohol to diesel fuel was limited by irregular combustion phenomena like degrading combustion quality and poor process controllability at low load and knock as well as auto-ignition at high load. With rising alcohol amount, a significant reduction of soot mass and particle number was observed. At some testing points, substituting diesel with ethanol, E65 or E85 led to a reduction of NOx emissions; however, the real benefit concerning the nitrogen oxides was introduced by the mitigation of the soot-NOx trade-off. The indicated engine efficiency in dual-fuel mode showed an extended tolerance against high EGR rates. It was significantly improved with enhanced substitution ratios at high loads, whereas it dropped at low loads.

Fuel cells as alternative propulsion systems in vehicles can achieve higher driving ranges and shorter refueling times compared to pure battery-electric vehicles, while maintaining the local zero-emission status. However, to take advantage of pure battery electric driving, an externally rechargeable battery can be combined with a fuel cell range extender. As part of a research project, an efficient air supply system for a fuel cell range extender was developed. To this end, a 25 kW PEM fuel cell system test bench was set up. The different parameter influences of the test bench, in particular of the air supply system, were analyzed and evaluated in terms of stack/system efficiency and functionality. The control software of the test bench was specifically developed for the flexible operating parameter variation. All adjustable variables of the system (air ratio, stack temperature, pressure, etc.) were varied and evaluated at steady-state operating points.

Future emission norms in India (BS6) necessitates the 2 wheeler industry to work towards emission optimization measures. Engine operation at stoichiometric Air-Fuel Ratio (AFR) would result in a good performance, durability and least emissions. To keep the AFR close to stoichiometric condition, an Oxygen sensor is placed in the exhaust system, which detects if air-fuel mixture is rich (λ<1) or lean (λ>1) and provides feedback to fuel injection system for suitable fuel control. O2 sensor has a ceramic element, which needs to be heated to a working temperature for its functioning. The ceramic element would break (thermal shock) if water in liquid form comes in contact with it when the element is hot.

The heat transfer process in a reciprocating engine is dominated by forced convection, which is drastically affected by mean flow, turbulence, flame propagation and its impingement on the combustion chamber walls. All these effects contribute to a transient heat flux, resulting in a fast-changing temporal and spatial temperature distribution at the surface of the combustion chamber walls. To quantify these changes in combustion chamber surface temperature, surface temperature measurements on the piston of a single cylinder diesel engine were taken. Therefore, thirteen fast-response thermocouples were installed in the piston surface. A wireless microwave telemetry system was used for data transmission out of the moving piston. A wide range of parameter studies were performed to determine the varying influences on the surface temperature of the piston.

Due to the new CO2 targets for vehicles, electrification of powertrains and operation strategies for electrified powertrains have drawn more attention. This article presents a predictive multi-objective operation strategy for hybrid electric vehicles (HEVs), which simultaneously minimizes the fuel consumption and the cycle aging of traction batteries. This proposed strategy shows better performance by using predictive information and high robustness to inaccuracy of predictive information. In this work, the benefits of the developed operation strategies are demonstrated in a strong hybrid electric vehicle (sHEV) with P2-configuration. For the cycle aging of a lithium-ion battery, an empirical model is built up with Gaussian processes based on experimental data.

As a consequence of the global warming, more strict maritime emission regulations are globally in force or will become applicable in the near future (e.g. NOX and SOX emission control areas). The tough competition puts economic pressure on the maritime transport industry. Therefore, the demand for efficient and mostly environmental neutral propulsion systems that meet the environmental legislations and minimize the cargo costs are immense. Medium speed dual fuel engines are in accordance with the strict maritime emissions legislation IMO Tier III. They do not require any exhaust gas aftertreatment, are economically competitive, and allow fuel flexibility. These engines deliver the highest efficiency in high load operation. A valuable approach to improve the efficiency and reduce the environmental impact in low and part load is represented by the electronic cylinder cut-out. Thereby, the natural gas admission is deactivated and the valves are kept activated.

The fuel spray behavior in the near nozzle region of a gasoline injector is challenging to predict due to existing pressure gradients and turbulences of the internal flow and in-nozzle cavitation. Therefore, statistical parameters for spray characterization through experiments must be considered. The characterization of spray velocity fields in the near-nozzle region is of particular importance as the velocity information is crucial in understanding the hydrodynamic processes which take place further downstream during fuel atomization and mixture formation. This knowledge is needed in order to optimize injector nozzles for future requirements. In this study, the results of three experimental approaches for determination of spray velocity in the near-nozzle region are presented. Two different injector nozzle types were measured through high-speed shadowgraph imaging, Laser Doppler Anemometry (LDA) and X-ray imaging.

The ongoing changes in the development of new power trains and the requirements due to driver assistance systems and autonomous driving could be the enabler for completely new brake system configurations. The shift in the brake load collective has to be included in the systems requirements for electric vehicles. Many alternative concepts for hydraulic brake systems, even for decentralized configurations, can be found in the literature. For a decentralized system with all state of the art safety functionalities included, four actuators are necessary. Therefore, the single brake module should be as cost-effective as possible. Previous papers introduced systems which are for example based on plunger-like concepts, which are very expensive and heavy due to the needed gearing and design. In this paper a comparison between a state of the art hydraulic brake system using an electromechanical brake booster, and a completely new decentralized hydraulic brake concept is presented.

This study presents a methodology to predict particle number (PN) generation on a naturally aspirated 4-cylinder gasoline engine with port fuel injection (PFI) from wall wetting, employing numerical CFD simulation and fuel film analysis. Various engine parameters concerning spray pattern, injection timing, intake valve timing, as well as engine load/speed were varied and their impact on wall film and PN was evaluated. The engine, which was driven at wide open throttle (WOT), was equipped with soot particle sampling technology and optical access to the combustion chamber of cylinder 1 in order to visualise non-premixed combustion. High-speed imaging revealed a notable presence of diffusion flames, which were typically initiated between the valve seats and cylinder head. Their size was found to match qualitatively with particulate number measurements. A validated CFD model was employed to simulate spray propagation, film transport and droplet impingement.

Compressed Natural Gas (CNG) is a promising alternative fuel for internal combustion engines as its combustion is fuel-efficient and lean in carbon dioxide compared to gasoline. The high octane number of methane gives rise to significant increase of the thermodynamic efficiency due to higher possible compression ratios. In order to use this potential, new stratified mixture formation concepts for CNG are investigated by means of numerical fluid simulations. For decades RANS methods have been the industry standard to model three-dimensional flows. Indeed, there are well-known deficiencies of the widely used eddy viscosity turbulence models based on the applied Boussinesq hypothesis. Reynolds stress turbulence models as well as scale resolving simulation approaches can be appealing alternative choices since they offer higher accuracy. However, due to their large computing effort, they are still mostly impractical for the daily use in industrial product development processes.

A previous study by the authors has shown an efficiency benefit of up to Δηi = 10 % for stratified operation of a high pressure natural gas direct injection (DI) spark ignition (SI) engine compared to the homogeneous stoichiometric operation with port fuel injection (PFI). While best efficiencies appeared at extremely lean operation at λ = 3.2, minimum HC emissions were found at λ = 2. The increasing HC emissions and narrow ignition time frames in the extremely lean stratified operation have given the need for a detailed analysis. To further investigate the mixture formation and flame propagation und these conditions, an optically accessible single-cylinder engine was used. The mixture formation and the flame luminosity have been investigated in two perpendicular planes inside the combustion chamber.