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Video

Maturity Level and Variant Validation of Mechatronic Systems in Commercial Vehicles

2011-12-05
Driver assistance systems (e.g. the emergency brake assist Active Brake Assist2, or ABA2 for short, in the Mercedes-Benz Actros) are becoming increasingly common in heavy-duty commercial vehicles. Due to the close interconnection with drivetrain and suspension control systems, the integration and validation of the functions make the most exacting demands on processes and tools involved in mechatronics development. Presenter Thomas Bardelang, Daimler AG
Video

Challenges in Automotive Electrification and Powertrain Component Development

2011-11-07
An overview of Daimler?s progression to advance powertrain technology in a growth industry shows many different solutions to improvement in transportation. Daimler continues to make breakthroughs in technology development and application building on 125 years of automotive development. Optimization of current powertrains will enable a significant gain in CO2/mi reductions, that dependent on product mix can be augmented with additional technologies. There is however no bypass to some form of electrification, enabling efficiency gains and alternative forms of power supply. Development of hybrid powertrains continues in an established manner and enhanced development of further electrified powertrains are in development. Organizationally and technically, significant skills and adjustments need to continue to be undertaken enabling OEMs and in particular the supply base to develop optimized solutions efficiently. The outlook is bright for novel component development and innovation.
Technical Paper

Numerical Investigation of Tonal Noise at Automotive Side Mirrors Due to Aeroacoustic Feedback

2020-09-30
2020-01-1514
In addition to the typical broadband noise character of wind noise, tonal noise phenomena can be much more disruptive, regardless of the overall interior noise quality of the vehicle. Whistling sounds usually occur by flow over sharp edges and resonant gaps, but can also be caused by the feedback of sound waves with laminar boundary layers or separation bubbles and the resulting frequency-selective growth of boundary layer instabilities. Such aeroacoustic feedback can e.g. occur at the side mirror of a vehicle and one compellingly needs the coupling of acoustic and flow field. A compressible large eddy simulation (LES) is in principle suitable but one has to take care of any numerical artifacts which can disturb the entire acoustic field. This paper describes the possibility to resolve aeroacoustic feedback with a commercial 2nd/3rd order finite volume CFD code.
Technical Paper

In-Cylinder Pressure Based Real-Time Estimation of Engine-Out Particulate Matter Emissions of a Diesel Engine

2011-04-12
2011-01-1440
The objective of this work was the development of a real-time capable in-cylinder pressure based diesel engine-out PM estimator. Two types of experimental passenger car DI diesel engines, equipped with in-cylinder pressure sensors have been used for the PM estimator development. Measurements have been taken during steady state and transient operation on an engine test bench. Using the Engine ECU signals and in-cylinder pressure data new parameters have been derived and used as inputs for an exponential zero dimensional modeling approach. Good correlation between the estimated and measured PM has been achieved for various experiments, not only for steady state operation points but also for transient measurements. Particularly, the model delivers good qualitative results, as well as good quantitative results in some regions. PM gradients, that is, the tendency of PM to increase or decrease from one engine operating point to another are represented successfully.
Journal Article

The NH3 Inhibition Effect in the Standard SCR Reaction over a Commercial Fe-zeolite Catalyst for Diesel Exhaust Aftertreatment: An Experimental and Modeling Study

2011-04-12
2011-01-1319
Transient and steady-state kinetic data are herein presented to analyze the inhibiting effect of ammonia on the NH₃-SCR of NO at low temperatures over a Fe-zeolite commercial catalyst for vehicles. It is shown that in SCR converter models a rate expression accounting for NH₃ inhibition of the Standard SCR reaction is needed in order to predict the specific dynamics observed both in lab-scale and in engine test bench runs upon switching on and off the ammonia feed. Two redox, dual site kinetic models are developed which ascribe such inhibition to the spill-over of ammonia from its adsorption sites, associated with the zeolite, to the redox sites, associated with the Fe promoter. Better agreement both with lab-scale intrinsic kinetic runs and with engine test-bench data, particularly during transients associated with dosing of ammonia to the SCR catalyst, is obtained assuming slow migration of NH₃ between the two sites.
Technical Paper

Challenges for the Next Generation of BlueTEC Emission Technology

2011-04-12
2011-01-0294
Mercedes-Benz BlueTEC passenger cars have been on the cutting edge of clean diesel technology since 2006. These BlueTEC vehicles furthermore passed millions of kilometers in the hands of customers. SCR-equipped passenger cars already meet the most stringent exhaust emissions standards in international markets such as the USA, Europe and Japan. Diesel engines with BlueTEC technology also reduce CO₂ emissions and provide the high torque and performance associated with the diesel engine in addition to keeping exhaust emissions at the lowest possible level. Nowadays the requirements for SCR emission concepts are increasing continuously. In fact the emission legislation is getting stricter with the LEVIII emission standards in 2015. Additionally the requirements and effort for on-board diagnosis are increasing year after year. In combination with ambitious CO₂ targets all these issues constitute the further challenges of BlueTEC SCR emission concepts for worldwide markets.
Technical Paper

Hydrogen Sensors for Automotive Fuel Cell Applications

2013-04-08
2013-01-0497
Since the last decade, alternative powertrains are playing an important role in the strategy of car manufacturers. One important goal is the introduction of zero emission powertrains. These powertrain systems raise increasing political and public interest with the hydrogen fuel cell engine being the most competitive powertrain technology. During the development of this new technology, all the functional aspects including the automotive vehicle safety need to be considered. Hydrogen sensors are installed in the system to optimize the performance of a hydrogen fuel cell system and to enhance the safety concept. New results of sensor optimization and innovative test and development methods based on real vehicle data are described in this paper.
Technical Paper

An Approach to Develop Energy Efficient Operation Strategies and Derivation of Requirements for Vehicle Subsystems Using the Vehicle Air Conditioning System as an Example

2013-04-08
2013-01-0568
Rising oil prices and increasing strict emission legislation force vehicle manufacturers to reduce fuel consumption of future vehicles. In order to meet this target, the process of converting fuel into useable energy and the use of this energy by the different energy-consuming vehicle's subsystems have to be examined. Vehicles' subsystems consist of energy-supplying, energy-consuming, and in some cases energy-storing components. Due to the high complexity of these systems and their interaction, optimization of their energy efficiency is a challenging task. By introducing individual operational strategies for each subsystem, it is possible to increase the energy efficiency for a specific function. To further improve the vehicle's overall energy efficiency, holistic control strategies are introduced that distribute the energy between the subsystems intelligently.
Technical Paper

Investigations of Spray-Induced Vortex Structures during Multiple Injections of a DISI Engine in Stratified Operation Using High-Speed-PIV

2013-04-08
2013-01-0563
Modern gasoline direct injection engines with spray-guided combustion processes require a stable and reliable fuel mixture formation as well as an optimal stratification at time of ignition. Due to the limited time for this process the temporal and spatial analysis of the in-cylinder flow field and its influence is of significant interest. The application of a piezo injector with outward opening nozzle and its capability to realize multiple injections within the compression stroke provides additional degrees of freedom for the stratified engine operation. To improve the performance of this combination a detailed knowledge of the in-cylinder flow field and its interaction with the spray propagation during and after multiple injections is essential. The flow field measurements were applied in an optical borescope single-cylinder research engine using a high-speed particle image velocimetry (HSPIV) setup.
Technical Paper

Numerical Simulation of the Transient Heat-Up of a Passenger Vehicle during a Trailer Towing Uphill Drive

2013-04-08
2013-01-0873
In the digital prototype development process of a new Mercedes-Benz, thermal protection is an important task that has to be fulfilled. In the early stages of development, numerical methods are used to detect thermal hotspots in order to protect temperature sensitive parts. These methods involve transient full Vehicle Thermal Management (VTM) simulations to predict dynamic vehicle heat-up during critical load cases. In order to simulate thermal control mechanisms, a coupled 1D to 3D thermal vehicle model is built in which the coolant and oil circuit of the engine, as well as the exhaust flow are captured in detail. When performing a transient 3D VTM analysis, the conduction and radiation phenomena are simulated using a transient structure model while the convective phenomena are co-simulated in a steady state fluid model. Both models are brought to interaction at predetermined points by an automatized coupling method.
Technical Paper

Stoichiometric Natural Gas Combustion in a Single Cylinder SI Engine and Impact of Charge Dilution by Means of EGR

2013-09-08
2013-24-0113
In this paper experimental results of a medium duty single cylinder research engine with spark ignition are presented. The engine was operated with stoichiometric natural gas combustion and additional charge dilution by means of external and cooled exhaust gas recirculation (EGR). The first part of this work considers the benefits of cooled EGR on thermo-mechanical stress of the engine including exhaust gas temperature, cylinder head temperature, and knock behaviour. This is followed by the analysis of the influence of cooled EGR on the heat release rate. In this context the impact of fuel gas composition is also under investigation. The influence of increasing EGR on fuel efficiency, which is caused by a changed combustion process due to higher fractions of inert gases, is shown in this section. By application of different pistons a relationship between the piston bowl geometry and the flame propagation has been demonstrated.
Journal Article

An Experimental Methodology for Measuring of Aerodynamic Resistances of Heavy Duty Vehicles in the Framework of European CO2 Emissions Monitoring Scheme

2014-04-01
2014-01-0595
Due to the diversity of Heavy Duty Vehicles (HDV), the European CO2 and fuel consumption monitoring methodology for HDVs will be based on a combination of component testing and vehicle simulation. In this context, one of the key input parameters that need to be accurately defined for achieving a representative and accurate fuel consumption simulation is the vehicle's aerodynamic drag. A highly repeatable, accurate and sensitive measurement methodology was needed, in order to capture small differences in the aerodynamic characteristics of different vehicle bodies. A measurement methodology is proposed which is based on constant speed measurements on a test track, the use of torque measurement systems and wind speed measurement. In order to support the development and evaluation of the proposed approach, a series of experiments were conducted on 2 different trucks, a Daimler 40 ton truck with a semi-trailer and a DAF 18 ton rigid truck.
Technical Paper

Performance Evaluation of Automotive HVAC System with the Use of Liquid Cooled Condenser

2014-04-01
2014-01-0681
Air-cooled fin and tube heat exchangers are used as a condenser in the conventional automotive Heating Ventilation & Air-Conditioning (HVAC) systems. In this study, the use of liquid cooled plate heat exchanger as a condenser in the automotive HVAC systems has been investigated. In the proposed configuration, the cabin heat absorbed by the refrigerant in HVAC system is rejected to the coolant through a liquid cooled condenser and then to the ambient air through a low temperature radiator. Hence, the proposed configuration combines heat rejection from HVAC system with a low temperature radiator circuit of power train cooling. Mixture of Ethylene glycol & Water (coolant), which is used in power train cooling system, is used as secondary fluid in the condenser.
Technical Paper

Development of Universal Brake Test Data Exchange Format and Evaluation Standard

2010-10-10
2010-01-1698
Brake system development and testing is spread over vehicle manufacturers, system and component suppliers. Test equipment from different sources, even resulting from different technology generations, different data analysis and report tools - comprising different and sometimes undocumented algorithms - lead to a difficult exchange and analysis of test results and, at the same time, contributes to unwanted test variability. Other studies regarding the test variability brought up that only a unified and unambiguous data format will allow a meaningful and comparative evaluation of these data and only standardization will reveal the actual reasons of test variability. The text at hand illustrates that a substantial part of test variability is caused by a misinterpretation of data and/or by the application of different algorithms.
Technical Paper

Towards an Aspect Driven Approach for the Analysis, Evaluation and Optimization of Safety Within the Automotive Industry

2010-04-12
2010-01-0208
An approach will be presented how development projects for safety-related and software-intensive automotive systems can be controlled through the application of model-based risk assessment. Therefore specific control measures have to be developed, which represent the degree of fulfilment of several aspects of safety-related developments. The control measures are evaluated through the analysis of risk-reducing aspects, for which the process of identification and specification is described. Thus, a framework for the creation of a probabilistic and aspect-oriented risk-analysis model (AORA) for safety related projects within automotive industries is currently under development. With respect to the upcoming safety standard ISO 26262 the twofold approach focuses on both, the identification and specification of risk-reducing aspects within the development as well as the application of a probabilistic reasoning model.
Journal Article

Modelling of NOx Storage + SCR Exhaust Gas Aftertreatment System with Internal Generation of Ammonia

2010-04-12
2010-01-0887
Combination of an NOx storage and reduction catalyst (NSRC, called also lean NOx trap, LNT) and a catalyst for the selective catalytic reduction of NOx by NH₃ (NH₃-SCR) offers a potential to significantly increase the efficiency of NSRC-based exhaust gas aftertreatment systems. Under most situations the SCR catalyst is able to adsorb the NH₃ peaks generated in the NSRC during the regeneration and utilize it for additional NOx reduction in the course of the consequent lean phase. This synergy becomes more important with the aged NSRC, where generally lower NOx conversions and higher NH₃ yields in wider range of operating temperatures are observed (in comparison with the fresh or de-greened NSRC). In this paper we present global kinetic models for the NSRC (Pt/Ba/Ce/gγ-Al₂O₃ catalyst type) and NH₃-SCR (Fe-ZSM5 catalyst type).
Technical Paper

Investigation on the Performance of a Mechanistic Electric Turbocharger Model for a Vehicular Fuel Cell System

2011-08-30
2011-01-1742
The electric turbocharger is a promising type of air supply unit for future automotive fuel cell drive systems. It comprises of a centrifugal compressor, a variable geometry turbine and a permanent magnet synchronous motor assembled on a single shaft. Compared to other types of vehicular fuel cell air supplies, like for example a screw or roots compressor, it needs less installation space and has lower weight while also causing less noise and vibration. This paper presents a validated mechanistic model of the electric turbocharger. The stationary compressor model is based on a set of aerodynamic loss models with surge and stone wall line prediction capability. Similarly, the stationary variable axial turbine is a detailed station based model derived from aerodynamic losses at the turbine wheel and the stator blades. The aerodynamic losses incorporated in the compressor and the turbine models are implemented under MATLAB/Simulink and show a good correlation with the experimental data.
Technical Paper

Standardization of Wiring Harness Data Formats between Truck OEMs and Suppliers

2011-09-13
2011-01-2270
The continuously integration of electrics and electronics (EE) in the last decades is one of the main key drivers for innovation and business success of the Automotive OEMs. This is also applicable for truck manufacturers. On the other side factors like the rising vehicle complexity, number of variants and the warranty costs for EE issues are increasing the pressure on the engineering teams responsible for the mechatronic systems. To address these issues one of the key activities in the European market (focus on Germany) during the last decade was to introduce industry-wide standards for the data transfer of wiring harness data between OEM and harness supplier. In this paper the benefits and technical background of using the standards KBL and KOMP formats within the MB-Trucks brand will be presented. Moreover the role of the Information Technology (IT) will be explained in detail.
Technical Paper

Maturity Level and Variant Validation of Mechatronic Systems in Commercial Vehicles

2011-09-13
2011-01-2263
Driver assistance systems (e.g. the emergency brake assist Active Brake Assist2, or ABA2 for short, in the Mercedes-Benz Actros) are becoming increasingly common in heavy-duty commercial vehicles. Due to the close interconnection with drivetrain and suspension control systems, the integration and validation of the functions make the most exacting demands on processes and tools involved in mechatronics development. In addition to a multi-stage test process focusing on the functions of the driver assistance systems (software), the “electrical” aspects (hardware) also form part of holistic maturity level validation. The test process is supported by state-of-the-art, high-performance tools (e.g. automatable component test benches and overall vehicle HiL systems) which, in particular, allow quick and accurate configuration in line with different vehicle variants.
Technical Paper

Investigations on Chemical Ageing of Diesel Oxidation Catalysts and Coated Diesel Particulate Filters

2010-04-12
2010-01-1212
For medium- and heavy-duty diesel engines, the development of new catalyst technologies and particulate filters is necessary to fulfill increasingly stringent emission regulations. An important aspect is the durability of the after-treatment system and therefore its efficiency over lifetime. Lubrication oil additives contain components such as phosphorous or zinc to ensure engine durability. Diesel oxidation catalyst (DOC) and coated diesel particulate filter (cDPF) catalytic coatings are negatively influenced by contamination on the surface with these components (chemical ageing). The components have a negative impact on the exhaust after-treatment systems performance. Additionally the cDPF is filled with oil ash. Engine tests are conducted to analyze the effect of lubrication oil additives on after-treatment system performance. In one study, lubrication oil with increased sulfur ash content is used.
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