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A new six-speed transaxle has been introduced by the Chrysler Group of DaimlerChrysler AG. Along with the six forward ratios in the normal upshift sequence, this transaxle features a seventh forward ratio used primarily in a specific downshift sequence. A significant technical challenge in this design was the control of so-called double-swap shifts, the exchange of two shift elements for two other shift elements. In the case at hand, one of the elements is a freewheel. A unique solution is discussed for successful control of double-swap shifts. The new design replaces a four-speed transaxle but makes use of a large percentage of parts and processes from the four-speed design. This approach enabled the new transaxle to reach production in three years from concept. The new transaxle, referred to as the 62TE, has substantially improved performance and passing maneuvers coupled with a new 4.0L high output engine for which the 62TE was developed.

In a subproject of the aim to develop a worldwide certification procedure for heavy-duty on-highway engines (WHDC), the measuring technique for future low emitting engines was evaluated. One aspect is the introduction of partial flow dilution systems for the particulates measurement during transient test cycles instead of the currently required full flow dilution systems. This paper presents an investigation about the influence of sensitive sampling parameters on particulate mass and composition under steady state and transient engine operating conditions, and their effect on the correlation between partial flow and full flow dilution systems. The study has shown that the sampling parameters investigated have no or only minor influence on particulate mass and composition. Both partial flow dilution systems proved their transient capability by tracking the exhaust flow signal very well.

Suspension systems have a major effect on the handling characteristics of a vehicle, particularly ride comfort and handling safety, and thus substantially determine its character. Their increasing significance is reflected by the greater value that ever more demanding customers attribute to the properties ride comfort and handling safety. Now that the potential of conventional, passive systems is largely exhausted, adaptive and active systems open up new possibilities, e.g.: the suppression of rolling and pitching movements, handling and ride height independent of load, handling characteristics and ride height adaptable to situation and customer requirement. The DaimlerChrysler active suspension and damping system (Active Body Control – ABC) manages to resolve the conflict of aims between handling safety and ride comfort which afflicts conventional fixed suspension systems, and as a result offers greater freedom of layout whilst enabling optimization of both target criteria.

In open jet wind tunnels with high blockage ratios a sharp rise in drag is observed for models approaching the nozzle exit plane. The physical background for this rise in drag will be analyzed in the paper. Starting with a basic analysis of the dependencies of the effect on model and wind tunnel properties, the key parameters of the problem will be identified. It will be shown using a momentum balance and potential flow theory that interaction between model and nozzle exit can result in significant tunnel-induced gradients at the model position. In a second step, a CFD-based investigation is used to show the interaction between nozzle exit and a bluff body. The results cover the whole range between open jet and closed wall test section interaction. The model starts at a large distance from the nozzle, then moves towards the nozzle, enters the nozzle and is finally completely inside the nozzle.

The results of a comprehensive experimental investigation into the exhaust emission performance and combustion properties of neat and blended Gas-To-Liquids (GTL) diesel fuel are presented. A sulphur-free European diesel fuel was used as the reference fuel, and two blends of the GTL diesel fuel with the reference fuel, containing 20% and 50% GTL diesel fuel respectively, were investigated. The study was based on a Mercedes Benz 2.2 liter passenger car diesel engine and presents emission data for both the standard engine calibration settings, as well as settings which were optimized to match the characteristics of each fuel. Vehicle emission tests showed that the GTL diesel fuel results in reductions in HC and CO emissions of greater than 90%, while PM is reduced by 30%, and NOx remains approximately unchanged. Engine bench dynamometer tests showed reductions in soot of between 30% and 60%, and NOx reductions of up to 10% with the GTL diesel fuel, depending on the operating point.

In the present study, the thermal comfort in a convertible has been evaluated using the in-house program TEKOS. The investigations have been performed for a SLK-class Mercedes with two occupants. The computational mesh consists of about 3 million hexahedra cells. TEKOS has been adapted to open driving conditions. The influence of the air-conditioning system and of different draft stops on the thermal comfort has been investigated in an autumn case. The study has shown, that in a basic case without draft stop and air conditioning the evaluation results in very poor thermal comfort values at the whole body, especially at unclothed parts of the body. If a draft stop and maximum heating is regarded, almost all parts of the body are close to the comfort range except of the head region. With TEKOS it is possible to quantify the influence of different parameters on the thermal sensation in convertibles with the advantage of an objective thermal evaluation.

This paper presents velocity and pressure measurements obtained around an isolated wheel in a rotating and stationary configuration. The flow field was investigated using LDA and a total pressure probe in the model scale wind tunnel at IVK/FKFS. Drag and lift were determined for both configurations as well as for the wheel support only. These results were used as a reference for comparing numerical results obtained from two different CFD codes used in the automotive industry, namely STAR-CD™ and PowerFLOW™. The comparison gives a good overall agreement between the experimental and the simulated data. Both CFD codes show good correlation of the integral forces. The influence of the wheel rotation on drag and lift coefficients is predicted well. All mean flow structures which can be found in the planes measured with LDA can be recognized in the numerical results of both codes. Only small local differences remain, which can be attributed to the different CFD codes.

The complexity of electrical/electronic vehicle systems mandates a systematic approach to the development of vehicle control, infotainment or comfort functions as well as the integration of these functions in an in-vehicle network consisting of several dedicated bus systems and according gateways. Due to reduced time-to-market, the integration has to be performed in a virtual environment. The classical Digital Mockup (DMU) addresses the physical integration of EE systems as mechanical components. However, functional aspects play a dominant role in EE vehicle systems. For this reason, functional integration defines a multi-view, mixed-level approach to the description, transformation, verification and integration of vehicle functions under consideration of the physical vehicle integration.

Heavy trucks are produced with a great variety of vehicle configurations, operate over a wide range of gross vehicle weight and sometimes function in extreme duty environments. Frontal crashes of heavy trucks can pose a threat to truck occupants when the vehicle strikes another large object such as bridge works, large natural features or another heavy-duty vehicle. Investigations of heavy truck frontal crashes indicate that the factors listed above all affect the outcome for the driver and the resulting damage to the truck Recently, a new chassis was introduced for on-highway heavy truck models that feature frontal airbag occupant protection. This introduction presented an opportunity to incorporate the knowledge gained from crash investigation into the process for developing the crash sensor's parameter settings.

The development of electronic intelligence and the continually increasing intensive knowledge of driving dynamics make it possible nowadays to conceive intelligent vehicle systems and to make such systems available for series production, which are capable of substantially enhancing the active safety of commercial vehicles. Through the implementation of advanced subsystems, which can be integrated as software packages into the basic electronic braking system, it will be possible to expand the possibilities of introducing assistance systems, which are capable of both, helping and relieving the driver from stress in critical situations. The driver will be relieved of all duties which could divert his attention or cause severe stress. As a consequence, the active safety of commercial vehicles will be considerably increased.

Today's interior systems engineer has been challenged with providing cost-effective instrument panel design solutions to meet NHTSA's new FMVSS 208 front crash regulations. Automotive manufacturers are in continuous search of newer methods and techniques to reduce prototype tests and cost. Analytical methods of predicting occupant and structural behavior using computer-aided engineering (CAE) analysis has been in place for quite some time. With the new FMVSS 208 regulations requiring both 5th and 50th percentile occupant testing, CAE analysis of predicting occupant response has become increasingly important. The CAE analyst is challenged with representing the barrier test condition, which involves the structure and the occupant moving at velocities of 25, 30 and 35 mph. Representing the cab kinematics in high-speed impacts is crucial, since capturing the vehicle intrusion and pitching should be made part of the input variables.

The current is an investigation of the effects of charge motion, namely tumble, on the burn characteristics of the new Chrysler Hemi SI engine. In order to reduce prototyping, several combustion system designs were evaluated; some of which were eliminated prior to design inception solely based on CFD simulations. The effects of piston top and number of spark plugs were studied throughout the conceptual stage with the AVL-FIRE CFD code. It has been concluded that large-scale, persistent and coherent tumbling flow structures are essential to charge motion augmentation at ignition only if such structures are decimated right before ignition. Piston top had a detrimental effect on tumbling charge motion as the piston approaches the TDC. When compared to single spark plug operation, dual spark plug reflected considerable improvement on burn characteristics and engine performance as a consequence. The CFD simulations demonstrated good correlation with early dynamometer data.

In the present study, the exterior air flow over convertibles together with the interior flow in the passenger compartment has been calculated using the commercial CFD program STAR-CD. The investigations have been performed for a SLK-class Mercedes with two occupants. The computational mesh consists of about 3 million hexahedra cells. The detailed informations of the calculated flow field have been used to elaborate the characteristic flow phenomena and increase the physical understanding of the flow. The influence of different geometrical modifications (variations of roof spoiler, variations of the draft stop behind the seats etc.) on the flow field and the air draft experienced by the occupants has been analyzed. To proof the accuracy of the numerical results, wind tunnel experiments in a full scale and 1:5 scale wind tunnel have been carried out for the basic car model as well as for several geometrical variations.

In the present paper, first results of an extensive and ongoing parametric study are shown. The objective of the parametric study is to clarify the influence of relevant flow and geometrical parameters on the microclimate and thermal comfort of the occupants. Flow parameters included in the study are air mass fluxes, velocity magnitude, air temperature and inflow direction at the vents. Geometrical parameters of interest are number, location, area and shape of the air vents as well as geometrical details of the passenger compartment itself. The parametric study is performed numerically on the basis of a computational model for a passenger compartment of a Mercedes E-Class sedan. The numerical method used has been published earlier and consists of a system of three programs for simulating the flow and temperature field in the cabin, the heat transfer and radiation and the thermal sensation of the occupants.

This paper addresses the use of neat, indigenous biodiesel in advanced Mercedes-Benz passenger cars. Modern, unmodified EU3 Common-Rail diesel engines with second generation common rail technology were used to determine the effects of neat biodiesel on performance and emission characteristics. The biodiesel was made from the seeds of the Jatropha Curcas plant and sourced from the Central Salt and Marine Chemicals Research Institute in Bhavnagar, India. The production of biodiesel and the vehicle tests are part of a PPP project, funded jointly by the DaimlerChrysler AG and the German DEG. The project aims at providing additional jobs and income in rural Indian areas along with reclaiming unused wasteland. The test vehicles were operated for a cumulative 8000 kilometers with an intention to expose the vehicle and fuel to diverse climatic conditions.

A new method for estimating the sound pressure level (SPL) at a defined position of the interior is presented. It is possible to recalculate the interior noise dependent on the sound radiated by specified panels which encloses the interior. It could be applied to analyse the interior acoustics under different operating conditions. This could be normal driving on real roads or pure wind noise inside wind tunnels. Also it is possible to study the interior noise under an artificial force excitation applied to the trimmed body. The method is based on the theoretical background of TPA (= Transfer Path Analysis /1/ ) via matrix inversion. It was tested on a simple cuboid structure with an artificial force excitation. The comparison of the measured and recalculated SPL of the interior shows a good correlation. Also the influence of some physical modifications at identified critical areas corresponds with the expected influence to the measured SPL inside this structure.

In view of tight emission standards, injection strategies to reduce raw HC-emissions during the cold starting of port fuel injected engines are evaluated in this study. The relevance of spray targeting and atomization is outlined in the first part of this paper. The foundation and performance of different injector concepts with respect to spray characteristics are discussed. Laboratory experiments demonstrate that concepts relying on auxiliary energy, such as air-assistance, fuel heating and injection at elevated system pressures, are capable of producing spray droplet sizes in the SMD-range of 25μm. For future injection strategies aimed at the compliance of SULEV emission levels, this target value is considered to be essential. In the second part of this paper, emission tests of selected injector concepts are carried out using a V6-3.2I ULEV engine operated both in a vehicle and on a test bench.

For the measurement of exhaust emissions, Constant Volume Sampling (CVS) technology is recommended by legislation and has proven its practical capability in the past. However, the introduction of new low emission standards has raised questions regarding the accuracy and variability of the CVS system when measuring very low emission levels. This paper will show that CVS has the potential to achieve sufficient precision for certification of SULEV concepts. Thus, there is no need for the introduction of new test methods involving high cost. An analysis of the CVS basic equations indicates the importance of the Dilution Factor (DF) for calculating true mass emissions. A test series will demonstrate that, by adjusting the dilution and using state of the art analyzers, the consistency of exhaust results is comparable with those of LEV concepts, measured with conventional CVS systems and former standard analyzers.

Investigations of the aerodynamic influence of rotating wheels on a simplified vehicle model as well as on a series production car are presented. For this research CFD simulations are used together with wind tunnel measurements like LDV and aerodynamic forces. Several wheel rim geometries are examined in stationary and in rotating condition. A good agreement could be achieved between CFD simulations and wind tunnel measurements. Based on the CFD analysis the major aerodynamic mechanisms at rotating wheels are characterized. The flow topology around the wheels in a wheel arch is revealed. It is shown, that the reduction of drag and lift caused by the wheel rotation on the isolated wheel and the wheel in the wheel arch are based on different effects of the airflow. Though the forces decrease at the front wheel due to the wheel rotation locally, the major change in drag and lift happens directly on the automotive body itself.

One of the world's most noble and high quality automobile brands is being revived: Maybach Aestetics, poise, perfection and technical brilliance founded the reputation of the magnificient Maybach sedans and convertibles, whose “Zeppelin” flagship, with a length of around 5.50 metres, was once the most prestigious German passenger car on the road - “an automobile which fulfills every last desire with refined elegance and power”, as the luxury automobile brand's brochure stated in 1934. DaimlerChrysler now feels obliged to live up to these high standards. As cornerstones of this vehicle concept, focus was placed on the topics of design, comfort, spatial availability, safety, exclusiveness and extra-ordinary performance. A major role was given to the powertrain in order to meet outstanding driving comfort and agility.