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A large number of testing procedures have been developed to ensure vehicle safety in common and extreme driving situations. However, these conventional testing procedures are insufficient for testing autonomous vehicles. They have to handle unexpected scenarios with the same or less risk a human driver would take. Currently, safety related systems are not adequately tested, e.g. in collision avoidance scenarios with pedestrians. Examples are the change of pedestrian behaviour caused by interaction, environmental influences and personal aspects, which cannot be tested in real environments. It is proposed to use augmented reality techniques. This method can be seen as a new (Augmented) Pedestrian in the Loop testing procedure.

Virtual sensing, i.e., the method of estimating quantities of interest indirectly via measurements of other quantities, has received a lot of attention in various fields: Virtual sensors have successfully been deployed in intelligent building systems, the process industry, water quality control, and combustion process monitoring. In most of these scenarios, measuring the quantities of interest is either impossible or difficult, or requires extensive modifications of the equipment under consideration – which in turn is associated with additional costs. At the same time, comprehensive data about equipment operation is collected by ever increasing deployment of inexpensive sensors that measure easily accessible quantities. Using this data to infer values of quantities which themselves are impossible to measure – i.e., virtual sensing – enables monitoring and control applications that would not be possible otherwise.

The upstream flow conditions and the use of tractive power to accelerate a vehicle are both sources of energy loss. The vehicle speed and the upstream flow conditions result in the oncoming wind vector experienced by the moving vehicle. The aim of the present work is to show a new approach to consider the chaotic and random behavior of surrounding flow conditions and their influence on driving performance. The approach is shown for the example of motorbike racing conditions. Special interest was put on a description of the flow conditions with respect to well know turbulent flow field parameters like the turbulent length scale or the turbulence intensity. Depending on where the flow conditions are measured, stationary in the earth reference frame, or on a moving vehicle, it is quite difficult to get a robust description of the flow field parameters. These parameters are used together with the Reynolds number to predict the aerodynamic behavior by correlation functions or maps.

Millions of small displacement single-cylinder engines are used for the propulsion of scooters, motorcycles, small boats and others. These SI-engines represent the basis of an affordable mobility in many countries, but at the same time their efficiency is quite low. Today, the limited fossil fuel resources and the anthropogenic climate require a sustainable development of combustion engines, the reduction of fuel consumption being an important factor. A variety of different strategies (turbo-charging, cylinder deactivation, direct injection, etc.) are investigated here to increase the efficiency of multi-cylinder engines. In the case of small displacement single-cylinder engines, other strategies are required because of their special design and the high pressure on costs. In the context of this paper different layout parameters which have an influence on the working process are investigated, with the aim of increasing the efficiency of small displacement single-cylinder engines.

Vehicle road tests are meaningful for investigations of creep groan noise. However, problems in reproducing experiments and partly subjective evaluations may lead to imprecise conclusions. This work proposes an experimental test and evaluation procedure which provides a precise and objective assessment of creep groan. It is based on systematic corner test rig experiments and an innovative characterization method. The exemplary setup under investigation consisted of a complete front wheel suspension and brake system including all relevant components. The wheel has been driven by the test rig’s drum against a brake torque. The main parameters within a test matrix were brake pressure and drum velocity. Both have been varied stepwise to scan the relevant operating range of the automobile corner system for potential creep groan noise. Additionally, the experiments were extended to high brake pressures, where creep groan cannot be observed under road test conditions.

This paper describes the development of a 0-D-sulfur poisoning model for a NOx storage catalyst (NSC). The model was developed and calibrated using findings and data obtained from a passenger car diesel engine used on testbed. Based on an empirical approach, the developed model is able to predict not only the lower sulfur adsorption with increasing temperature and therefore the higher SOx (SO2 and SO3) slip after NSC, but also the sulfur saturation with increasing sulfur loading, resulting in a decrease of the sulfur adsorption rate with ongoing sulfation. Furthermore, the 0-D sulfur poisoning model was integrated into an existing 1-D NOx storage catalyst kinetic model. The combination of the two models results in an “EAS Model” (exhaust aftertreatment system) able to predict the deterioration of NOx-storage in a NSC with increasing sulfation level, exhibiting higher NOx-emissions after the NSC once it is poisoned.

It is critical for gas and dual fuel engines to have improved transient characteristics in order that they can successfully compete with diesel engines. Testing of transient behavior as well as of different control strategies for the multi-cylinder engine (MCE) should already be done on the single cylinder engine (SCE) test bed during the development process. This paper presents tools and algorithms that simulate transient MCE behavior on a SCE test bed. A methodology that includes both simulation and measurements is developed for a large two-stage turbocharged gas engine. Simple and fast models and algorithms are created that are able to provide the boundary conditions (e.g., boost pressure and exhaust back pressure) of a multi-cylinder engine in transient operation in real-time for use on the SCE test bed. The main models of the methodology are discussed in detail.

The reduction of environmentally harmful gases and the ambitions to reduce the exploitation of fossil resources lead to stricter legislation for all mobile sources. Legislative development significantly affected improvements in emissions and fuel consumptions over the last years, mainly measured under laboratory conditions. But real world operating scenarios have a major influence on emissions and it is already well known that these values considerably differ from officially published figures [1]. There are regulated emissions by the European Commission by means of real driving scenarios for passenger cars. A methodology to measure real drive emissions RDE is therefore well approved for automotive applications but was not adapted for two-wheeler-applications yet [2]. Hence measurements have been performed on-road and on chassis dynamometer for motorcycles with the state of the art RDE measurement equipment to be prepared for possible future legislation.

In electrified vehicles, auxiliary units can be a dominant source of noise, one of which is the refrigerant scroll compressor. Compared to vehicles with combustion engines, e-vehicles require larger refrigerant compressors, as in addition to the interior, also the battery and the electric motors have to be cooled. Currently, scroll compressors are widely used in the automotive industry, which generate one pressure pulse per revolution due to their discontinuous compression principle. This results in speed-dependent pressure fluctuations as well as higher-harmonic pulsations that arise from reflections. These fluctuations spread through the refrigeration cycle and cause the vibration excitation of refrigerant lines and heat exchangers. The sound transmission path in the air conditioning heat exchanger integrated in the dashboard is particularly critical. Various silencer configurations can be used to dampen these pulsations.

This paper introduces a research project on a spark ignition engine used in non-road applications. The aim is to illustrate the present situation as basis for comparison and to identify possible improvement potential in terms of performance, efficiency or exhaust and noise emissions. The study is carried out in two steps. First a standard walk-behind lawn mower is equipped with measuring instrumentation for recording the cutting forces and the engine variables during real world operation. The tests are carried out on three different lawn types and two different blade types are investigated. Consequently, in a second step the engine is analysed on the engine test bench in stationary and transient operating mode. A complete engine mapping is done regarding all relevant variables. Additionally to the outdoor tests, fuel consumption and engine out emissions are measured on the engine dynamometer. The recorded data enables a detailed analysis of the engine behaviour.

Synergies in infrastructure and customer acceptance can be achieved by running internal combustion engines on mixtures of hydrogen and natural gas. Alongside the bridging effect between natural gas and hydrogen, such mixing offers advantages in terms of reduced emissions and improvements to the combustion process. The wide ignition limits and high flame speed of hydrogen have as positive an impact on the combustion of H2NG mixture as does the higher energy density of natural gas on range. A bi-fuel gasoline-natural gas vehicle was adapted to operation with gasoline, natural gas, hydrogen and any H2NG mixtures. For that purpose, the intake manifold was replaced by an aluminum construction, the injectors were replaced and the ECU had to be adjusted. Essentially quality-controlled hydrogen operation was possible throughout the engine map.

Nowadays, investigating underhood airflow by using numerical simulation is a standard task in the development process of passenger cars and commercial vehicles. Numerous publications exist which deal with simulating the airflow through the engine compartment of road vehicles. However, hardly anything can be found which deals with off-road vehicles and nothing exists which focuses on snowmobiles. In the presented paper the airflow and the thermal conditions inside the engine compartment of a snowmobile are investigated by the usage of computational fluid dynamics (CFD) as well as experimental methods. Field tests at arctic conditions have been conducted on a serial snowmobile to measure temperatures inside the compartment and to gain realistic boundary conditions for the numerical simulation. Thermocouples (type K) were attached under the hood to measure exhaust, air, coolant and surface temperatures of several components at previously defined load cases.

In-cylinder flows in internal combustion engines are highly turbulent in nature. An important property of turbulence that plays a key role in mixture formation is anisotropy; it also influences ignition, combustion and emission formation. Thus, understanding the turbulence anisotropy of in-cylinder flows is critical. Since the most widely used two-equation Reynolds-averaged Navier-Stokes (RANS) turbulence models assume isotropic turbulence, they are not suitable for correctly capturing the anisotropic behavior of turbulence. However, large eddy simulation (LES) can account for the anisotropic behavior of turbulence. In this paper, the Reynolds stress tensor (RST) is analyzed to assess the predictive capability of RANS and LES with regard to turbulence anisotropy. The influence of mesh size on turbulence anisotropy is also looked into for multi-cycle LES.

Friction losses as well as lube oil consumption at the piston group are key factors for future engine downsizing concepts regarding to emissions and consumption. This means an early identification of friction losses and wear is essential within development. The main problem is that the wear assessment is based on long durability tests which are typically performed in a later phase. This may lead to the fact that an early optimized configuration with respect to friction can cause a potential wear problem later in the durability test program. Still ongoing trends in combustion engine engineering lead to both the minimized oil supply in the tribocontact piston bore interface and improved wear resistance. One is forced to the conclusion that understanding and quantifying wear will be a key driver for the future engine development process. The aim is a holistic concept that combines different methods to investigate wear and furthermore its combination with friction loss studies.

Volatile oil prices and increased environmental sensitivity together with political concerns have moved the attention of governments, automobile manufacturers and customers to alternative power trains. From the actual point of view the most promising concepts for future passenger cars are based on the conversion of electrical into mechanical energy. In-wheel motors are an interesting concept towards vehicle electrification that provides also high potentials to improve vehicle dynamics and handling. Beside aspects concerning the electric system (e.g. motor type, energy storage, and control strategy), there are also some open questions related with the mechanical design of in-wheel motor driven vehicles that need to be solved before series production.

There are several different possibilities to analyze a squealing brake system. The present paper introduces a complex measuring system which is mounted on a complete vehicle axle at a test rig. This system was developed because the previously performed state-of-the-art tests did not allow any insights in the squeal triggering mechanisms. First of all, a frequency analysis was performed. Thereby the main vibrating parts and the directions of the oscillation could be determined during a squeal event. The second was a modal analysis of the vehicle axle, which was necessary to get further insights into the system as well as to verify an existing Finite Element Method model. Through these tests, however, it was not possible to get any insight into the contact area, and therefore it was impossible to determine the squeal triggering mechanism. Because of this limitation, special guide pins were developed, which are able to measure the vibrating friction force.

Brake wear particles are recognized as one of the dominant sources of road transport particulate matter emissions and are linked to adverse health effects and environmental impact. The UNECE mandated the Particle Measurement Program to address this issue, by developing a harmonized sampling and measurement methodology for the investigation of brake wear particles on a brake dynamometer (dyno). However, although the brake dyno approach with tightly controlled test conditions offers good reproducibility, a multitude of changing vehicle and surrounding conditions make real-driving emissions measurement a highly relevant task. Here we show two different prototypes for on-road particle measurement with minimal impact of the measurement setup on the emission behavior, tested on a brake dyno.

In consideration of the fact that in extreme Enduro competitions two-stroke motorcycles are still dominating, the Institute of Internal Combustion Engines and Thermodynamics, Graz University of Technology, with a long tradition in two-stroke technology, has developed a new 300 cm3 two-stroke motorcycle engine. The 2-stroke LPDI (Low Pressure Direct Injection) technology was originally developed for the 50 cm3 Scooter and moped market in Europe. In 50 cm3 applications the LPDI technology fulfils the EURO 4 emission standard (2017) [1]. In a next step the LPDI technology was applied to a 250 cm3 Enduro engine demonstrator vehicle. Based on the results of the demonstrator, a complete new high performance 300 cm3 engine was developed. The development of this new engine will be described in this publication. Some interesting aspects of the layout with 3D-CFD methods and also 1D-CFD simulation to optimize the exhaust system by DoE methods are discussed in the paper.

Small engines for non-automotive applications include 2-stroke and 4-stroke gasoline engine concepts which have a reduced number of sensors due to cost and packaging constraints. In order to cope with future emission regulations, more sophisticated engine control and monitoring becomes mandatory. Therefore, a cost-effective way has to be found to gain maximum information from the existing sensors and actuators. Due to an increasing bio-fuel share in the market, the detection of bio-fuel content is necessary to guarantee a stable combustion by adapting the injection and ignition control strategy. Meaningful information about the combustion can be retrieved from combustion chamber ion current measurements. This paper proposes a general overview of combustion process monitoring in different engine concepts by measuring the ion current during combustion.

The mathematical thermal design of the vehicle brakes will lead to success if all influence parameters such as friction (fading effect), car geometry and inertia, brake amplifier, tire, convective heat flow, heat conductance and heat radiation are taken into consideration. In addition to a lot of design criteria, the thermal stability of the vehicle brake is becoming more and more important because of permanently increasing engine powers and weight of the vehicles. This requires both stable friction behavior in the contact zone between brake lining and brake disk and a sufficient transfer of the friction energy by means of convective heat flow. In order to accomplish these two tasks, considerable expense on a brake test bed and innumerable brake trials are necessary. It must be guarantied at the end of the brake design process that the vehicle reaches the required braking distance and the thermal stability of the brake, e.g. after several freeway braking sequences.