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Hybrid and Electric vehicles present special challenges when developing a customer-selectable Economy Mode, as the vehicles are already energy-efficient by design. This paper analyzes the sources of sub-optimal fuel economy in: energy generation, vehicle usage, and customer usage. The paper first reviews the effects on customer acceptance from other implementations of Economy Mode, using “Things Gone Wrong” data from customer surveys on competitive vehicles. This information was used as lessons learned for the new design. The paper then discusses which changes to vehicle functionality could be implemented to improve fuel economy while maintaining acceptable vehicle performance, along with acceptable noise, vibration, and harshness objectives. The vehicle parameters studied in this paper include: 12 V loads, engine operating commands of torque and speed, EV operating limits, customer demand inputs, regenerative braking, cruise control operation, and climate control function.

Sound barrier materials come in many varieties. They are generally described as being dense, high mass, and impervious to airflow. Until recently, lightweight foams have not generally been recognized or utilized as sound barriers. However, closed cell foam is an effective sound barrier that performs in accordance with the Mass Law. It can be used in many applications where a lightweight barrier is sufficient, avoiding the penalty of excessive mass relative to the noise reduction required. Sound absorption does not generally accompany the sound transmission loss performance of a sound barrier material. Recently developed closed cell foam with significant sound absorption properties is described. This paper describes the production of closed cell foam and the fabrication of parts from this material. A visual tour of material production and part fabrication is presented. Material characteristics and typical applications are described.

This paper presents two methods of characterizing and describing the formability of tailor welded blanks (TWB). The first method involves using miniature tensile specimens, extracted from TWB weld material, to quantify mechanical properties and material imperfection within TWB welds. This technique combines statistical methods of describing material imperfection together with conventional M-K method modeling techniques to determine safe forming limit diagrams for weld material. The second method involves the use of an extended M-K method modeling technique, which places multiple material thickness and material imperfections inside one overall model of TWB performance. These methods of describing TWB formability and their application to specific aluminum TWB populations are described.

Tailor welded blanks are finding increasing application in automotive structures as a powerful method to reduce weight through material minimization. As consumer demand and regulatory pressure direct the automotive industry toward improved fuel efficiency and reduced emissions, aluminum alloys are also becoming an attractive automotive structural material with their potential ability to reduce vehicle weight. The combination of aluminum and tailor welded blanks thus appears attractive as a method to further minimize vehicle weight. Two major concerns regarding the application of aluminum tailor welded blanks are the formability and durability of the weld materials. The current work experimentally and numerically investigates aluminum tailor welded blanks ductility, and experimentally investigates their fatigue resistance.

The transportation industry is finding an ever-increasing number of applications for products manufactured using the tubular hydroforming process. Most of the current hydroforming applications use steel tubes. However, with the mounting regulatory pressure to reduce vehicle emissions, aluminum alloys appear attractive as an alternative material to reduce vehicle weight. The introduction of aluminum alloys to tubular hydroforming requires knowledge of their forming limits. The current work investigates the forming limits of AA6061 in both the T4 and T6 tempers under laboratory conditions. These experimental results are compared to theoretical forming limit diagrams calculated via the M-K method. Free hydroforming results and forming limit diagrams are also compared to components produced under commercial hydroforming conditions.

The introduction of the LDCR common rail injection system has opened up new possibilities in controlling the details of the injection rate and the spray characteristics. In particular, there is potential to optimize engine performance across the speed and load range, if a nozzle can be developed which has the facility to vary the final orifice area over the operating range of the engine. There are a number of different geometries which may achieve the required effects. Two possible methods are to throttle either the entrance or the exit of the nozzle holes to a greater or lesser extent, according to the engine running condition. The paper describes an investigation of the spray characteristics of entry and exit throttled orifices, and how they are affected by pressure levels and degrees of opening. In previous studies, large scale transparent models have accurately reproduced the different spray characteristics observed with actual nozzles.

The paper describes how laser light sheet illumination was used to study the onset and development of cavitation in a scaled up plain orifice nozzle. In addition, measurements were taken using laser Doppler velocimetry and the refractive index matching technique, and these establish the velocity profiles within the orifice under non-cavitating conditions. The light sheet makes visible new detail in the cavitating flow field and additional stages in the cavitation process are identified. The mechanism which causes hydraulic flip is demonstrated and confirms the authors' hypothesis from previous studies. An investigation into the form which the cavitation takes is included: flow conditions are demonstrated in which the cavitation produces an opaque mass of small bubbles, and alternative conditions in which large transparent vapour pockets are produced.

Computer simulation of the hydraulic and mechanical functions has been used extensively in the development of the Company's Electronic Unit Injector for truck engines: the EUI-200. The program was developed in house as part of a long tradition of simulating diesel fuel injection equipment. The paper describes the role of simulation in the product development, from testing the feasibility of design concepts, through the development phases, and into serial production. Specific examples show the sizing and optimization of some of the key design details. Sensitivity analyses revealed the critical manufacturing processes and were helpful in diagnosing and solving a problem with one particular batch of prototypes. Two stage and electronic pilot injection developments are described, as well as some fundamental analyses of the injection performance, through the identification of cavitating and non-cavitating flow regimes in the nozzle spray.

An investigation into the different flow structures which exist in the holes of direct injection nozzles and their corresponding large scale acrylic models is described. Some effects of different experimental methods are discussed. Results obtained under steady flow conditions are compared with those from transient tests. The correct use of large scale models is found to enable the interpretation and clarification of the results obtained with actual nozzles. The effect of flow cavitation in the nozzle holes is clarified. New information concerning the state of the injected fuel is included. The relationships between cavitation and the spray abnormality, hydraulic flip, and between cavitation and atomization are established. The spray characteristics of single hole nozzles are contrasted with those of standard multihole sac type nozzles.