Ferit Küçükay

Measurement and fatigue damage evaluation of road profiles in customer operation

In this paper, the simulation of customer operation by means of the 3D (Driver, Driven vehicle, Driving environs) method is used to evaluate stochastic and transient road profiles with regard to the fatigue damage influence to chassis components. For this purpose road profile statistics are derived from extensive measurements on public roads. A special road profile measurement system was developed for getting information about road profile statistics in customer operation. Measurements were done in three different markets. The 3D method and multibody dynamics simulation are used to evaluate and compare the fatigue damage influence of road profiles in different markets.

Energy Management for Fuel-Cell Hybrid Vehicles Based on Specific Fuel Consumption Due to Load Shifting

Energy management is integral to the design of fuel-cell (FC) hybrid vehicles (FCHVs), as well as topology and component sizing. Therefore, an optimal energy management strategy is crucial for a successful FCHV concept. The goal in this optimization process is to coordinate the energy sources and power components on a vehicle in such a way that the total consumption is minimized. We defined a new strategy that quantifies the shifts in the operating point (OP) of the FC system by using the specific fuel consumption due to load shifting and adapts the conditions for a possible shifting of the OP of the FC system to reduce the total fuel consumption. This paper shows the simulation results of the proposed strategy in comparison with existing strategies. The main focus is given on the improvement in fuel consumption, the effect of the new approach on utilization of the power sources concerning their aging mechanisms, and the effect of varying conditions by time. The results indicate that the goal of reduction in total fuel consumption is achieved.

The automotive transmission book

This book presents essential information on systems and interactions in automotive transmission technology and outlines the methodologies used to analyze and develop transmission concepts and designs. Functions of and interactions between components and subassemblies of transmissions are introduced, providing a basis for designing transmission systems and for determining their potentials and properties in vehicle-specific applications: passenger cars, trucks, buses, tractors, and motorcycles. With these fundamentals the presentation provides universal resources for both state-of-the-art and future transmission technologies, including systems for electric and hybrid electric vehicles

Virtual real-time environment for automatic-transmission control units in the form of hardware-in-the-loop

Short development times, early verification of design and function, and efficient use of development expenditure make it necessary for the step from the real world to the virtual world to be taken at an early stage of the project. This also, and in particular, applies to the development of electronic control units for passenger cars. This paper describes the configuration of a Hardware-In-the-Loop (HIL) test stand for electronic transmission control units used in automatic-transmission vehicles. The complete environment of the control unit - the so-called DRV parameters Driver, Route and Vehicle - is replaced by a new virtual real-time environment which is designed to match the specific application in question. Text and development options offered by HIL simulation are illustrated in the form of examples. These include verification of individual functions under reproducible conditions and long-time simulation under real-time conditions.

Non-parametric modelling of damper top mounts

This paper details a new non-linear damper top-mount model, and the processes utilized to identify the constituent parameters. The damper top-mount model parameters are extracted from experimental data on commercial damper top mounts. The non-parametric restoring-force-mapping technique is used to construct the damper top-mount model. A damper top-mount model that consists of three elements, which are the non-linear elastic element, the non-linear friction element and the non-linear viscous element, is developed. The amplitude dependence of the top-mount characteristics is modelled by using the friction element and the elastic element, while the frequency dependence of the top mount is modelled by using the restoring-force-mapping technique. In order to obtain and optimize the required model parameters, a new procedure based on a two-stage optimization routine using two different sets of the measurement data for the amplitude-dependent parameters and the frequency-dependent parameters, is proposed. The model is validated by comparing the measured and simulated forces for three different damper top mounts. Good agreement between the measured force and the simulated force is obtained. Furthermore, the proposed model is found to be superior to the existing rubber isolator models.

A reference architecture for CISS/CDAS within the field of cooperative driving

The V2V communication is a promising technology aiming at the growing demands on safety, comfort and efficiency. A variety of research projects demonstrate the expandability of the V2V communication across the boundaries of current industry standards. The authors divide the expandability into two key aspects: collective scene description and cooperative maneuvers. This article combines the expandability of the V2V communication with systematically deduced essential automotive requirements and the challenges of a distributed decision making process. That leads to a reference architecture for cooperative driver assistance systems (CDAS) and cooperative integrated safety systems (CISS), uniting the flexibility for several implementations and a defined focus by the help of clear modules and interfaces. This article verifies the reference architecture using a cooperative merging onto a highway with a focus on the diversity of feasible implementation. The reference architecture arranges the field of research in separate problems and stimulate discussions about the proposed interfaces as an important step to future standards. Further research will gradually address the separate modules to establish the performance of CDAS/CISS and evaluate several concept variants.

Optimization of Damper Top Mount Characteristics to Improve Vehicle Ride Comfort and Harshness

A novel optimization technique for optimizing the damper top mount characteristics to improve vehicle ride comfort and harshness is developed. The proposed optimization technique employs a new combined objective function based on ride comfort, harshness, and impact harshness evaluation. A detailed and accurate damper top mount mathematical model is implemented inside a validated quarter vehicle model to provide a realistic simulation environment for the optimization study. The ride comfort and harshness of the quarter vehicle are evaluated by analyzing the body acceleration in different frequency ranges. In addition, the top mount deformation is considered as a penalty factor for the system performance. The influence of the ride comfort and harshness weighting parameters of the proposed objective function on the optimal damper top mount characteristics is studied. The dynamic stiffness of the damper top mount is used to describe the optimum damper top mount characteristics for different optimization case studies. The proposed optimization routine is able to find the optimum characteristics of the damper top mount which improve the ride comfort and the harshness performances together.

Multi-body Dynamics Analysis of Power Train Judder Oscillations Considering Aggregate Dynamics

Torsional oscillations in an open power train during start-up process are commonly called judder or clutch judder. Due to the rotational-translational coupling of tyres and body the longitudinal acceleration of the car passengers is, according to the appearing magnitudes, affected in a way that their driving comfort may be disturbed notably. Main subject of this paper is the simulation of judder oscillations. Additionally it provides a single-mass flywheel clutch model, which is integrated in a multi-body dynamics power train model to analyse the different mechanisms of judder. The results show, on the one hand, the massive influence of aggregate roll and stroke motions on judder vibrations, so it can be said that the clutch is not the only cause of those disturbances. On the other hand, a parameter study exposes sensitive values in the power train that have impact on those oscillations. Finally, different clutch concepts are compared with regard to judder.

Vergleich Unterschiedlicher Systeme zur Aktiven Antriebsmomentenquerverteilung

Dank einer radlastangepassten Ausnutzung des Kraftschlusspotenzials ermoglichen querverteilende Antriebssysteme insbesondere bei frontangetriebenen Fahrzeugen eine deutliche Erhohung der Agilitat und der Fahrleistungen. Das Institut fur Fahrzeugtechnik der Technischen Universitat Braunschweig fuhrte Simulationsstudien fur einen systematischen Konzeptvergleich dieser Systeme durch.

Reproducible transverse dynamics vehicle evaluation in the double lane change

In automotive companies, designing the vehicle dynamics to be customer-oriented with the help of road trials is largely the responsibility of trained professional drivers. A driver model that corresponds to an average — and therefore customer-relevant — driver presents an opportunity to evaluate the vehicle in an objective and reproducible way. This vehicle evaluation was developed at Volkswagen in close cooperation with the Institute for Vehicle Technology at Technical University Braunschweig (Germany).