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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.

Coming along with the present movement towards the ultimately variable engine, the need for clear and simple models for complex engine systems is rapidly increasing. In this context Common-Rail-Systems cause a special kind of problem due to of the high amount of parameters which cannot be taken into consideration with simple map-based models. For this reason models with a higher amount of complexity are necessary to realize a representative behavior of the simulation. The high computational time of the simulation, which is caused by the increased complexity, makes it nearly impossible to implement this type of model in software in closed loop applications or simulations for control purposes. In this paper a method for decreasing the complexity and accelerating the computing time of automotive engine models is being evaluated which uses an optimized method for each stage of the diesel engine process.

In a gasoline engine, the unswept in-cylinder residual gas and introduction of external EGR is one of the important means of controlling engine raw NOx emissions and improving part load fuel economy via reduction of pumping losses. Since the trapped in-cylinder Residual Gas Fraction (RGF, comprised of both internal, and external) significantly affects the combustion process, on-line diagnosis and monitoring of in-cylinder RGF is very important to the understanding of the in-cylinder dilution condition. This is critical during the combustion system development testing and calibration processes. However, on-line measurement of in-cylinder RGF is difficult and requires an expensive exhaust gas analyzer, making it impractical for every application. Other existing methods, based on measured intake and exhaust pressures (steady state or dynamic traces) to calculate gas mass flowrate across the cylinder ports, provide a fast and economical solution to this problem.

This paper examines the conformability of elastic piston rings to a distorted cylinder bore. Several bounds are available in the literature to help estimate the maximum allowable Fourier coefficient in a Fourier expansion of bore distortion: the analytically derived bounds in [7] and [8], and the semi-empirically derived bounds discussed in [9]. The underlying assumptions for each set of analytic bounds are examined and a multiple order algorithm is derived. The proposed algorithm takes account of multiple orders of distortion at once. It is tested with finite element (FE) data and compared to the classical bound approach. The results indicate that the bounds in [7] are compatible with linear elasticity theory (LET), whereas the bounds in [8] are not. Furthermore, numerical evidence indicates that the present multiple order algorithm can predict seal breaches more accurately than either of the other analytic bounds.

The increase of active safety will demand more and more electronic intelligence, if a drastic optimization of conventional systems is not possible any more. Starting from today's mechatronic systems, the trend leads via tomorrow's smart electronic systems to the future electronic networking of all intelligent vehicle systems. The paper describes the present status of these systems in Europe and the possibilities of increasing the active safety by using electronic intelligence.

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.

Charge motion is known to accelerate and stabilize combustion through its influence on turbulence intensity and flame propagation. The present work investigates the effect of charge motion generated by intake runner blockages on combustion characteristics and emissions under part-load conditions in SI engines. Firing experiments have been conducted on a DaimlerChrysler (DC) 2.4L 4-valve I4 engine, with spark range extending around the Maximum Brake Torque (MBT) timing. Three blockages with 20% open area are compared to the fully open baseline case under two operating conditions: 2.41 bar brake mean effective pressure (bmep) at 1600 rpm, and 0.78 bar bmep at 1200 rpm. The blocked areas are shaped to create different levels of swirl, tumble, and cross-tumble. Crank-angle resolved pressures have been acquired, including cylinders 1 and 4, intake runners 1 and 4 upstream and downstream of the blockage, and exhaust runners 1 and 4.

Because of the rapidly increasing amount of electronic components and busses in a vehicle, the use of gateways in Electronic Control Units (ECUs) becomes more important. The upcoming question is how to design an optimal gateway. This paper describes a method for designing an optimal automotive gateway in an FPGA by using Evolutionary Algorithms (EAs). The complete gateway functionality is diagrammed in a specification graph which consists of a function graph and an architecture graph. The function graph describes the complete functionality of the gateway. The architecture graph shows the variety of the different implementation options of the mapped function graph. Each gateway task in the function graph can be realized either in a parallel way (different kinds of hardware implementations) or in a sequential way (software on a microprocessor core).

Topology optimization in structural analysis is known for many years. In the presented procedure, “topology optimization” is used for computational fluid dynamics (CFD) for the first time. It offers the possibility of a very fast optimization process under utilization of the physical information in the flow field instead of using optimization algorithms like for example evolution strategies or gradient based methods. This enables the design engineer to generate in a first layout air guiding systems with low pressure drop in a fast and easy manner, which can than be improved further due to constraints of styling or production requirements. This procedure has been tested with many examples and shows promising results with a reduction in pressure loss up to 60% compared to a duct designed in CAD in the traditional way.

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.

This paper introduces the new 1.6L engine family, designed and developed by the Chrysler group of DaimlerChrysler Corporation in cooperation with BMW. An overview of the engine's design features is provided, with a detailed review of the performance development process with emphasis on airflow, combustion, thermal management and friction. This information is presented, to provide an understanding of how the engine simultaneously achieves outstanding levels of torque, power, fuel consumption, emissions and idle stability. The use of analytical tools such as Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) in the optimization of the engine is shown.

In order to fulfill the need for an efficient and reliable computational method for the aerodynamic optimization of passenger cars, a numerical simulation strategy has been developed at DaimlerChrysler in Stuttgart. The simulation strategy consists of surface preparation, three dimensional mesh generation, flow simulation using CFD, and post-processing. The method will be applied mainly in the early concept phase of the development process when 1:4 scale models with smooth underbodies are used. In this study SAE-bodies as well as modifications of real car shapes are presented. The paper also discusses which improvements are needed to establish a mainly CFD-based process in the early concept phase.

A project was undertaken to demonstrate an engine stop/start at idle system utilizing a 12 volt Belt driven Starter Generator (BSG). The system was developed on a production four cylinder vehicle to determine emissions, driveability, and fuel economy impact.

This investigation evaluated different pressure transducers in one cylinder to examine the combustion measurement differences between them simultaneously. There were a total of eleven transducers ranging in both diameter and type of transducer (piezo-electric, piezoresistive, and optical). Furthermore, the sensors differed in the methodology for minimizing signal distortion due to temperature. This methodology could take the form of various size mounting passages, heat shields, watercooling or heat transfer paths. To evaluate the sensors, different engine operating conditions were conducted, focusing at full load and low speeds. Other hardware configurations of the same engine family were used to exaggerate the combustion environment, specifically a tumble-motion plate and turbocharging.

Today, a number of simulation codes are available for pre-designing gas exchange systems of IC engines with good accuracy (e.g. PROMO, WAVE, GT-Power). However, optimizing such systems still requires numerous time consuming and inefficient trial and error runs. Also, accounting for constraints as size, volume, peak combustion pressure etc. multiplies the necessary efforts additionally. Hence there is a strong need for efficient procedures for finding optimum designs automatically and reliably. To automatically find the global optimum design parameters under a given set of real constraints of a practical case, a multi-membered evolution-strategy based optimization code was developed. The code which efficiently finds the true optimum dimensions of gas exchange systems (duct lengths, duct diameters, volumes) of an IC engine. The code can be readily generalized, and adapted to arbitrary optimization problems.

Whereas the verification of non-safety-related, embedded software typically focuses on demonstrating that the implementation fulfills its functional requirements, this is not sufficient for safety-relevant systems. In this case, the control software must also meet application-specific safety requirements. Safety requirements typically arise from the application of hazard and/or safety analysis techniques, e.g. FMEA, FTA or SHARD. During the downstream development process it must be shown that these requirements cannot be violated. This can be achieved utilizing different techniques. One way of providing evidence that violations of the safety properties identified cannot occur is to thoroughly test each of the safety requirements. This paper introduces Evolutionary Safety Testing (EST), a fully automated procedure for the safety testing of embedded control software.

The paper includes the development steps used in creating a station test apparatus (STA) and a description of the apparatus design. The purpose of this device is to simulate hydrogen vehicle conditions for the verification of gaseous hydrogen refueling station dispenser performance targets and hydrogen quality. This is done at the refueling station/vehicle interface (i.e. the refueling nozzle.) In addition, the device is to serve as a means for testing and developing future advanced fueling algorithms and protocols. The device is to be outfitted with vehicle representative container cylinders and sensors located inside and outside the apparatus to monitor refueling rate, ambient and internal gas temperature, pressure and weight of fuel transferred. Data is to be recorded during refueling and graphed automatically.

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.