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The need for efficient space utilization has provided a framework for the design of a 248mm family of torque converters that supports a wide choice of engine and transmission combinations. The axial length of the part and its weight have been substantially reduced while the performance range has been broadened without degradation of efficiency. The new converter operates in an expanded slipping clutch mode. It significantly contributes to the performance and fuel economy improvements of related vehicles. To meet the cost target, the comprehensive lineup and the resulting complexity have required a high level of component interchangeability. During the design phase, the manufacturing core competencies were scrutinized and process redundancies eliminated, both resulting in optimization of material selection and applicable technology.

This paper presents a method for optimization design of an engine mounting system subjected to some constraints. The engine center of gravity, the mount stiffness rates, the mount locations and/or their orientations with respect to the vehicle can be chosen as design variables, but some of them are given in advance or have limitations because of the packaging constraints on the mount locations, as well as the individual mount rate ratio limitations imposed by manufacturability. A computer program, called DynaMount, has been developed that identifies the optimum design variables for the engine mounting system, including decoupling mode, natural frequency placement, etc.. The degree of decoupling achieved is quantified by kinetic energy distributions calculated for each of the modes. Several application examples are presented to illustrate the validity of this method and the computer program.

A continuously variable lift, duration and phase mechanical lift mechanism is described, as applied to the intake valvetrain of a SOHC, 4-valve per cylinder, four-cylinder production engine. Improvements in fuel economy were sought by reduction of pumping losses and improved charge preparation, and optimization of WOT torque was attempted by variation of intake valve closing angle. Adjustment of the mechanism is achieved by movement of the pivot shaft for the rocker arms. The relationship between lift, duration and phase is predetermined at the design stage, and is fixed during operation. There is considerable design flexibility to achieve the envelope of lift curves deemed desirable. The operation of the mechanism is described, as are the development procedure, testing with fixed cams, some cycle simulation, friction testing on a separate rig and dyno testing results for idle, part load and WOT.

Ford introduced a new in-line 4-cylinder 2.3L DOHC 16-valve engine in its European D-class Scorpio vehicle. The engine is based on the proven 2.0L-DOHC engine with 8 or 16 valves. The new engine replaces the 2.0L DOHC 8-valve version. Primary focus of the development of this new 2.3L engine was on the noise and vibration improvement, both for the engine and for the vehicle interior noise. One measure to achieve this target was the application of balance shafts. In this paper, the development of the new engine will be described from the design stage to the production version. It will focus on the design of the balance shaft housing and all relevant engine NVH features. The various stages of the design and detailed optimization are explained. The NVH prediction by CAE methods is verified with experimental results. The influence of optimized components like the oil pan, front cover and the chain tensioner on the noise behavior will be discussed.

Vehicle thermal protection is an important aspect of the overall vehicle development process. It involves optimizing the exhaust system routing and designing heat shields to protect various components that are in near proximity to the exhaust system. Reduced time to market necessitates an efficient process for thermal protection development. A robust procedure that utilizes state of the art CFD simulation techniques proactively during the design phase is described. Simulation allows for early detection of thermal issues and development of countermeasures several months before prototype vehicles are built. Physical testing is only used to verify the thermal protection package rather than to develop heat shields. The new procedure reduces the number of physical tests and results in a robust, efficient methodology.

NVH refinement is an important aspect of the powertrain development process. Powertrain NVH refinement is influenced by overall sound levels as well as sound quality. The sound quality and hence the level of powertrain NVH refinement can be negatively affected by the presence of excessive impulsive noise. This paper describes a process used to develop an understanding of impulsive powertrain noise. The paper begins with an introductory discussion of various sources of impulsive noise in an automotive powertrain. Following this, the paper outlines a process for identifying the source of the impulsive powertrain noise using examples from case studies. The remainder of the paper focuses on certain examples of impulsive noise such as Diesel knocking noise, injector ticking, impulsive cranktrain noise, and gear rattle. For these examples, the development of key objective metrics, optimization measures, and improvement potential are examined.

Variable Valve Actuation (VVA) technology provides high potential in achieving high performance, low fuel consumption and pollutant reduction. However, more degrees of freedom impose a big challenge for engine characterization and calibration. In this study, a simulation based approach and optimization framework is proposed to optimize the setpoints of multiple independent control variables. Since solving an optimization problem typically requires hundreds of function evaluations, a direct use of the high-fidelity simulation tool leads to the unbearably long computational time. Hence, the Artificial Neural Networks (ANN) are trained with high-fidelity simulation results and used as surrogate models, representing engine's response to different control variable combinations with greatly reduced computational time. To demonstrate the proposed methodology, the cam-phasing strategy at Wide Open Throttle (WOT) is optimized for a dual-independent Variable Valve Timing (VVT) engine.

The reduction of the fuel consumption and the emissions are the two main goals for the development of current and future engines. Both consumption and emissions are highly influenced by the fluid and the material temperatures of the engine. This offers potential especially at low engine speeds and engine loads to reduce the cooling power and increase the material temperatures to a tribologic and thermodynamic optimized level. The cooling system which is able to control the cooling power and the material temperatures, the required control devices and the control strategy are designated as intelligent heat management. The definition of the requirements for the control devices and the definition of the control strategies requires detailed knowledge about the thermal engine behavior.

Modern passenger car engines are designed to operate at increasingly higher rated engine speeds with more internal parts (multi-valve engines) requiring lubrication. The paper presents results of research and development activities to reduce the actual feed rate of the oil consumers to their real requirements depending on the most significant influence parameters. Based on these results an optimization strategy is presented which combines CAE tools with data from experimental work. In the conclusion of the paper recommendations are summarized to show the optimization potential of actual lubrication and ventilation systems concerning design. power input respectively oil consumption.

Low frequency torsional vibrations can be a significant source of objectionable vehicle vibrations and in-vehicle boom, especially with changes in engine operation required for improved fuel economy. These changes include lower torque converter lock-up speeds and cylinder deactivation. This paper has two objectives: 1) Examine the effect of increased torsional vibrations on vehicle NVH performance and ways to improve this performance early in the program using test and simulation techniques. The important design parameters affecting vehicle NVH performance will be identified, and the trade-offs required to produce an optimized design will be examined. Also, the relationship between torsional vibrations and mount excursions, will be examined. 2) Investigate the ability of simulation techniques to predict and improve torsional vibration NVH performance. Evaluate the accuracy of the analytical models by comparison to test results.

A new multi-layer co-extruded in-color Ionomer film is developed to provide an alternative decoration process to replace paint on Dodge Neon Fascias. The Ionomer film provides a high-gloss “class-A” surface in both non-metallic and metallic colors that match the car body paint finish. Using the Ionomer film to decorate fascias reduces cost; eliminates VOCs; increases manufacturing flexibility and improves performance (weatherability and durability). The molding process consists of thermoforming a film blank and injection molding Polypropylene or TPO behind the film. The paper will include the background, the benefits, the technology development objectives, the film materials development, tooling optimization, film fascia processing (co-extrusion; thermoforming and injection molding) and validation testing of the film.

The NVH optimization is a key issue for the development of future powertrains. This includes the radiated noise in terms of noise level and sound quality as well as the structure-borne noise excitation via the engine mounts. Experience shows that there are generally no single noise relevant components on modern powertrains which dominate the NVH behaviour. In contrast, a good NVH performance can only be achieved if the optimization process includes every single component and excitation. Only the combination of these optimized designs can lead to a first-class powertrain NVH. Within this paper the NVH optimization process of an existing 4-cylinder in-line spark-ignition powertrain is described. Examples for positive NVH designs are presented and their effect on the NVH behaviour are explained. Combining all positive NVH features into the engine resulted in a noise reduction of 3-5 dBA without any negative effect on fuel economy and performance.

In automotive industry, all passenger vehicles are treated with damping materials to reduce structure borne noise. The effectiveness of damping treatments depends upon design parameters such as choice of damping materials, locations and size of the treatment. This paper proposes a CAE (Computer Aided Engineering) methodology based on finite element analysis to optimize damping treatments. The developed method uses modal strain-energy information of bare structural panels to identify flexible regions, which in turn facilitates optimization of damping treatments with respect to location and size. The efficacy of the method is demonstrated by optimizing damping treatment for a full-size pick-up truck. Moreover, simulated road noise performances of the truck with and without damping treatments are compared, which show the benefits of applying damping treatment.

This paper reflects an efficient and comprehensive approach for vehicle sound optimization integrated into the entire development process. It shows the benefits of early consideration of typical vehicle NVH features and of intensive interaction of P/T and vehicle responsibilities. The process presented here considers the typical restriction that acoustically representative prototypes of engines and vehicles are not available simultaneously at the early development phase. For process optimization at this stage, a method for vehicle interior noise estimation is developed, which bases on measurements from the P/T test bench only, while the vehicle transfer behavior for airborne and structure-borne noise is assumed to be similar to a favorable existing vehicle. This method enables to start with the pre- optimization of the pure P/T and its components by focusing on such approaches which are mainly relevant for the vehicle interior noise.

The automotive industry is rapidly implementing computer simulation in every aspect of their processes mainly to decrease the time required to bring new models to market. Computer simulation can also be used to reduce the cost of vehicle development and manufacturing. A major portion of the manufacturing cost associated with automotive stamping lies in the process design, build and tryout of production dies and in automation of the transfer equipment. Press home-line tryout is largely a trial-and-error process relying heavily on the skills and experience of tool and die makers. To reduce this dependence on human skills and effort, press-line simulation can be effectively utilized to verify the design accuracy thereby reducing the changes needed to rework the production die/tool. The entire press-line with all its complete accessories can be modeled and checked for design errors similar to the try-out conducted in the production plant.

Buffeting is a wind noise of high intensity and low frequency in a moving vehicle when a window or sunroof is open and this noise makes people in the passenger compartment very uncomfortable. In this paper, side window buffeting was simulated for a typical SUV using the commercial CFD software Fluent 6.0. Buffeting frequency and intensity were predicted in the simulations and compared with the corresponding experimental wind tunnel measurement. Furthermore, the effects of several parameters on buffeting frequency and intensity were also studied. These parameters include vehicle speed, yaw angle, sensor location and volume of the passenger compartment. Various configurations of side window opening were considered. The effects of mesh size and air compressibility on buffeting were also evaluated. The simulation results for some baseline configurations match the corresponding experimental data fairly well.

This paper presents a new approach to improve occupant response in a front impact event. Instead of designing a vehicle structure for maximum structural efficiency and safety and then engineer a restraint system for the vehicle, this paper proposes to use a systems approach. In this approach, the vehicle structural response during impact (i.e., pulse) and the restraint system are considered together in the optimization process. In this paper, the 35 mph front impact into a rigid barrier with belted occupants, which is the NHTSA NCAP test, will be used to demonstrate the proposed new approach.

Due to the contradiction of the market demands and legal issues OEMs are forced to invest in finding concepts that assure high fuel economy, low exhaust emissions and high specific power at the same time. Since mechanical losses may amount up to 10 % of the fuel energy, a key to realise such customer/government specific demands is the improvement of the mechanical performance of the engines, which comprises mainly friction decrease and lightweight design of the engine parts. In order to achieve the mentioned objectives, it has to be checked carefully for each component whether the design potentials are utilized. Many experimental studies show that there is still room for optimization of the cranktrain parts, especially for the crankshaft. A total exploitation of the crankshaft potentials is only possible with advanced calculation approaches that ensure the component layout within design limits.