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The BMW Group has introduced electric cars to the market with the MINI E already in 2009. The next step will be the launch of the BMW ActiveE in 2011, followed by the revolutionary Mega City Vehicle in 2013. The presentation will explain the BMW Group strategy for implementing sustainable mobility. A focus will be emobility, the use of carbon fiber and the holistic sustainability approach of BMW Group?s project i. Reference will be made to the research results of the MINI E projects in the US and in Europe. Presenter Andreas Klugescheid, BMW AG

It is essential to include uncertainties in the simulation process in order to perform reliable vibroacoustic predictions in the early design phase. In this contribution, uncertainties are quantified using the generalized Polynomial Chaos (gPC) expansion in combination with a Finite Element (FE) model of a vehicle body in white. It is the objective to particularly investigate the applicability of the gPC method in the industrial context with a high number of uncertain parameters and computationally expensive models. A non-intrusive gPC expansion of first and second order is implemented and the approximation of a stochastic response process is compared to a Latin Hypercube sampling based reference solution with special regard to accuracy and computational efficiency. Furthermore, the method is examined for other input distributions and transferred to another FE model in order to verify the applicability of the gPC method in practical applications.

During the last decades, big steps have been taken towards a realistic simulation of NVH (Noise Vibration Harshness) behavior of vehicles using the Finite Element (FE) method. The quality of these computation models has been substantially increased and the accessible frequency range has been widened. Nevertheless, to perform a reliable prediction of the vehicle vibroacoustic behavior, the consideration of uncertainties is crucial. With this approach there are many challenges on the way to valid and useful simulation models and they can be divided into three areas: the input uncertainties, the propagation of uncertainties through the FE model and finally the statistical output quantities. Each of them must be investigated to choose sufficient methods for a valid and fast prediction of vehicle body vibroacoustics. It can be shown by rough estimation that dimensionality of the corresponding random space for different types of uncertainty is tremendously high.

This paper describes a novel approach for modeling an automotive HVAC unit. The model consists of black-box models trained with experimental data from a self-developed measurement setup. It is capable of predicting the temperature and mass flow of the air entering the vehicle cabin at the various air vents. A combination of temperature and velocity sensors is the basis of the measurement setup. A measurement fault analysis is conducted to validate the accuracy of the measurement system. As the data collection is done under fluctuating ambient conditions, a review of the impact of various ambient conditions on the HVAC unit is performed. Correction models that account for the different ambient conditions incorporate these results. Numerous types of black-box models are compared to identify the best-suited type for this approach. Moreover, the accuracy of the model is validated using test drive data.

Highly automated driving (HAD) is under rapid development and will be available for customers within the next years. However the evidence that HAD is at least as safe as human driving has still not been produced. The challenge is to drive hundreds of millions of test kilometers without incidents to show that statistically HAD is significantly safer. One approach is to let a HAD function run in parallel with human drivers in customer cars to utilize a fraction of the billions of kilometers driven every year. To guarantee safety, the function under test (FUT) has access to sensors but its output is not executed, which results in an open loop problem. To overcome this shortcoming, the proposed method consists of four steps to close the loop for the FUT. First, sensor data from real driving scenarios is fused in a world model and enhanced by incorporating future time steps into original measurements.

The development of hydrogen-fueled vehicles has created the need for established fuel consumption testing methods. Until now the EPA has only accepted three methods of hydrogen fuel consumption testing, gravimetric, PVT (stabilized pressure, volume and temperature), and Coriolis mass flow; all of which necessitate physical measurements of the fuel supply [1]. BMW has developed an equation and subsequent testing methods to accurately and effectively determine hydrogen fuel consumption in light-duty vehicles using only exhaust emissions. Known as “Hydrogen-Balance”, the new equation requires no changes to EPA procedures and only slight modifications to most existing chassis dynamometers and CVS (Constant Volume Sampling) systems. The SAE 2008-01-1036, also written by BMW, explains the background as well as required equipment and changes to the CVS testing system. This paper takes hydrogen balance further by testing it against the three EPA established forms of fuel consumption.

The Hydrogen-Balance equation makes it possible to calculate the fuel economy or fuel consumption of hydrogen powered vehicles simply by analyzing exhaust emissions. While the benefits of such a method are apparent, it is important to discuss possible influencing factors that may decrease Hydrogen-Balance accuracy. Measuring vehicle exhaust emissions is done with a CVS (Constant Volume Sampling) system. While the CVS system has proven itself both robust and precise over the years, utilizing it for hydrogen applications requires extra caution to retain measurement accuracy. Consideration should be given to all testing equipment, as well as the vehicle being tested. Certain environmental factors may also play a role not just in Hydrogen-Balance accuracy, but as also in other low emission testing accuracy.

Today's automotive software integration is a static process. Hardware and software form a fixed package and thus hinder the integration of new electric and electronic features once the specification has been completed. Usually software components assigned to an ECU cannot be easily transferred to other devices after they have been deployed. The main reasons are high system configuration and integration complexity, although shifting functions from one to another ECU is a feature which is generally supported by AUTOSAR. The concept of a Virtual Functional Bus allows a strict separation between applications and infrastructure and avoids source code modifications. But still further tooling is needed to reconfigure the AUTOSAR Basic Software (BSW). Other challenges for AUTOSAR are mixed integrity, versioning and multi-core support. The upcoming BMW E/E-domain oriented architecture will require all these features to be scalable across all vehicle model ranges.

The reduction of vehicle exhaust particle emissions is a success story of European legislation. Various particle number (PN) counters and calibration procedures serve as tools to enforce PN emission limits during vehicle type approval (VTA) or periodical technical inspection (PTI) of in-use vehicles. Although all devices and procedures apply to the same PN-metric, they were developed for different purposes, by different stakeholder groups and for different target costs and technical scopes. Furthermore, their calibration procedures were independently defined by different stakeholder communities. This frequently leads to comparability and interpretation issues. Systematic differences of stationary and mobile PN counters (PN-PEMS) are well-documented. New, low-cost PTI PN counters will aggravate this problem. Today, tools to directly compare different instruments are scarce.

The development of a leanburn engine is described, in which optimized engine design, innovative engine management and exhaust gas aftertreatment using a special NOx-storage catalyst were combined to yield a significant improvement in fuel economy with reduced NOx emissions. To achieve stable combustion near the lean limit a swirl system was used and the appropriate parameters of the 2.2 I 4-cyIinder 4-valve SI engine were optimized. As a result, the mixture formation was improved and the lean limit was extended to higher air-fuel ratios. An adaptive lambda controller which was based on the evaluation of engine-smoothness calculated from the RPM-sensor was implemented to control each cylinder individually close to the lean limit. A model-based control system was developed to achieve extremely accurate air-fuel ratio control during transients.

For meeting 21st-century exhaust emission standards for HD diesel engines, new methods are necessary for reducing NOx and PM emissions without increasing fuel consumption. The stratified diesel fuel-water-diesel fuel (DWD) injection in combination with exhaust gas recirculation (EGR) is as a means for NOx and PM reduction without any negative effect on fuel economy. The investigation was performed on a charged HD single-cylinder direct-injection diesel engine with a modern low-swirl combustion system, 4-valve technology and high pressure injection. The application of DWD injection combined with EGR resulted in a 60 percent lower NOx emission at full load and a 75 percent reduced NOx emission at part load when compared with present day (EURO II) technology. This was achieved without any fuel economy penalty, but with an additional PM emission reduction.

The active safety of tractor / trailer-combinations plays an important role in regard to traffic safety in general. For improving the active safety of tractor / trailer-combinations, it is necessary to investigate the interactions between the towing vehicle and the trailer during braking maneuvers. This paper describes the ECE-regulations for the braking force distributions of tractor/full trailer- and tractor / semitrailer-combinations. The influence of different layouts of the braking systems within these regulations on the coupling forces between tractor and trailer and the driving performance of the units during braking is investigated. The dynamical behaviour of a tractor/full-trailer-combination and a tractor / semitrailer-combination are both discussed with the aid of simulations of the ISO-standard testing procedures “Braking in a turn” and “Braking straight ahead”.

Wheel slip control system have found a remarkable penetration in all car segments. The information on the wheel behavior has lead to further developments which control the brake performance as well as the driving of the car in general. Latest systems introduced especially on luxury cars use wheel individual brake intervention to ensure vehicle stability under various driving maneuvers within the physical limits. Such systems use vehicle dynamic sensors and special hydraulics which serve as energy source for the automatic brake application. The technical effort of such systems like the Dynamic Stability Control DSC has limited the installation to upper class cars so far. New approaches are required to allow for a more wide spread penetration. Optimized hydraulics together with a rational design of the electronics seems to offer a basis for a more cost effective design.

In this paper a systematic approach is presented for the design and optimization of forced liquid cooled electronic modules with high power dissipation. The steps of the design cycle include hydrodynamical evaluation of the heat sink, thermal management, thermomechanical optimization and especially lifetime prediction of soldered joints. Utilized engineering tools comprise Computational Fluid Dynamics, Finite Differences and Finite Element programs. These are coupled via software interfaces in order to enable data exchange as well as efficient cooperation of the designers. Applying these means performance, reliability and costs of a certain module have been optimized. By use of a design-for-reliability procedure substantial savings with regard to development time, prototyping effort and consequently costs can been achieved.

An adsorber system for reducing cold start hydrocarbon (HC) emissions has been developed combining existing catalyst technologies with a zeolite-based HC adsorber. The series flow in-line concept offers a passive and simplified alternative to other technologies by incorporating one additional adsorber substrate into existing converters without any additional valving, purging lines, or special substrates. This contribution describes the current development status of hydrocarbon adsorber aftertreatment technologies. We report results obtained with a variety of adsorber, start-up, and underfloor catalyst system combinations. In each case, it was possible to achieve HC emission levels in compliance with the ULEV standards, and in the best cases, demonstrating HC emissions substantially below the legislated standard.

To meet LEV and EU Stage III emission requirements, it is necessary for new catalytic converters to be designed which exceed light-off temperature as quickly as possible. The technical solutions are secondary air injection, active heating systems such as the electrically heated catalytic converter, and the close coupled catalytic converter. Engine control functions are extensively used to heat the converter and will to play a significant role in the future. The concept of relocating the converter to a position close to the engine in an existing vehicle involves new conflicts. Examples include the space requirements, the thermal resistance of the catalytic coating and high temperature loads in the engine compartment.

During the design, evaluation and optimization process of automotive brake systems brake torque measurements are often crucial. Known brake torque sensors lead to differences in terms of mass, inertia, stiffness and brake cooling compared to a vehicle without measurement equipment. In this contribution a new brake torque sensor is described which proved to be superior to known systems. Either the hub itself is turned into the sensing element or is replaced by a sensing element. Thus mass, inertia, stiffness and cooling conditions are nearly unchanged. A modification of this sensor allows measurement of residual brake torques in a low range (20....50 Nm) with high sensivity and features at the same time a high range (up to 2.000 Nm) with lower sensivity. The application of the sensor in a study to lower energy loss caused by residual brake friction in a passenger car is described.

A common rail injection system was applied to port-loop and uniflow scavenged two-stroke DI-Diesel engines. While the uniflow scavenged configuration was operated with a swirl level comparable to that of 4-stroke DI-Diesel engines, no swirl motion was realized with the port-loop scavenged arrangement. The results show that, in spite of disadvantages in the mixture formation process, the high mixture formation energy observed with the common rail injection makes a swirl-free Diesel combustion possible. However, at part load the combustion process and emission level with the port-loop scavenged engine is not satisfactory. At full load, disadvantages in the scavenging process are observed in addition to the poorer mixture formation with the loop scavenged two-stroke concept. Consequently, the expected specific power output of the port-loop scavenged arrangement is with 20 kW/l far lower than about 45 kW/l predicted for the uniflow scavenged engine.

In conjunction with throttle-free load control on a 4-valve, single-cylinder spark-ignition engine, the influencing variables of charge cycle, mixture formation and combustion process are presented both as computer calculations and on the basis of test results. The influences of the position of the maximum of the inlet valve stroke, the position of the inlet close, the shape of the valve stroke and the load motion in relation to the maximum power and minimum fuel consumption are investigated in full load by computer calculations and in partial load by engine tests.

In the present work we investigated experimentally and computationally the unsteady flow around a BMW car model including wheels*. This simulation yields mean flow and turbulence fields, enabling the study aerodynamic coefficients (drag and lift coefficients, three-dimensional/spatial wall-pressure distribution) as well as some unsteady flow phenomena in the car wake (analysis of the vortex shedding frequency). Comparisons with experimental findings are presented. The computational approach used is based on solving the complete transient Reynolds-Averaged Navier-Stokes (TRANS) equations. Special attention is devoted to turbulence modelling and the near-wall treatment of turbulence. The flow calculations were performed using a robust, eddy-viscosity-based ζ - ƒ turbulence model in the framework of the elliptic relaxation concept and in conjunction with the universal wall treatment, combining integration up to the wall and wall functions.