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Camless Variable Valve Actuation (VVA) technologies have been known for improving fuel economy, reducing emissions, and enhancing engine performance. VVA can be divided into electro-magnetic, electro-hydraulic, and electro-pneumatic actuation. A family of camless VVA designs (called LGD-VVA or Gongda-VVA) has been presented in an earlier SAE publication (SAE 2007-01-1295) that consists of a two-spring actuation, a bypass passage, and an electrohydraulic latch-release mechanism. The two-spring pendulum system is used to provide efficient conversion between the moving mass kinetic energy and the spring potential energy for reduced energy consumption and to be more robust to the operational temperature than the conventional electrohydraulic actuation; and the electrohydraulic mechanism is intended for latch-release function, energy compensation and seating velocity control.

Extensive crash sled testing and analysis has recently led to the development of a new HANS prototypes for use in FIA F1. The performance of HANS prototypes has been studied with various conditions of HANS design geometry and impact direction. The new HANS prototypes have been found to substantially reduce injurious motions and forces of the head and neck, and the new HANS is lighter, more compact, and performs better than the currently available HANS. Use of HANS by FIA F1 drivers has been initiated.

In an effort to create computer models to promote rapid, cost-effective prototyping while easing design changes, more information about how people interact with seats is needed. Predicting the occupant location, their geometry, and motion within a vehicle leads to a better determination of safety restraint location, controls reach, and visibility - factors that affect the overall operation of the vehicle. Based on the Michigan State University JOHN model, which provides a biomechanical simulation of the torso posture, experiments were conducted to examine the change of postures due to seat and interior package factors. The results can be incorporated into the posture prediction model of the RAMSIS program to give a more detailed prognosis of the spine curvature and refine the model-seat interactions. This paper will address findings of the experimental study with relation to model development.

Since the 1960's, automotive seats have been designed and evaluated with tools and procedures described in the SAE Recommended Practice J826. The SAE J826 design template and testing manikin each have a torso with a flat lower back shape and with a single joint at the H-point. The JOHN models provide a more anatomically detailed representation of human shape and movement. The articulations of the JOHN torso (pelvic, lumbar, and thoracic) segments are coupled so that their relative positions are determined by a single parameter related to spinal curvature. This paper describes the development and use of the JOHN biomechanical models for seating design.

Deformations of soft tissues and seat cushion foam are significant factors in determining the interface contours between the seat and the back of the thigh. This paper describes the measurement of forces, deformations, and contours of people's thighs and seat cushion materials. The goal of this work is to represent the human interactions with seats. A two-dimensional, plane strain finite element method was used to develop a contact model between the cross section of the human mid-thigh and flat surfaces, which can be a flat, rigid surface or a flat, foam cushion of various thicknesses and densities. Results of human and seat interactions for various subjects were measured, modeled, and compared. The present work showed a good agreement between experiments and models for various subjects and foam densities. The important results showed that the stiffness of the foam does not depend on the foam thickness.

Driver and passenger comfort, as related to automotive seats, is a growing issue in the automotive industry. As this trend continues, automotive seat designers and developers are generating a greater need for more anthropometrically accurate tools to aid them in their work. One tool being developed is the JOHN software program that utilizes three-dimensional solid objects to represent humans in seated postures. Contours have been developed to represent the outside skin surfaces of three different body types in a variety of postures in the sagittal plane. These body types include: the small female, the average male, and the large male.

To assist automotive seat development and evaluation, a technique for predicting the posture of seated occupants has been developed. The method involved modeling the torso geometry and articulation of a mid-size male, based on information presented in SAE paper number 930110 [1]. This mid-size male model, known as 2-D JOHN, was developed in a commercial kinetic modeling software and used in a comparative seat evaluation study between a current production automotive seat and a prototype articulating seat. The 2-D JOHN model was supported a greater range of postures, defined as Total Lumbar Curvature (TLC) and Torso Recline Angle (TRA), in the prototype seat than the automotive seat.

Seat factors are characteristics of seats that influence people's postures. Seat factors such as lumbar prominence and seat pan stiffnesses were defined and measured for a variety of automotive seats. Seat factors such as these serve as a basis for evaluating and comparing seats. They were useful for selecting seats and designing experiments for human subject testing in the ASPECT program. Seat factors are also candidates for independent variables in statistical posture prediction models. The Seat factors described in this paper were measured with the current J826 manikin. They will be redefined for use with the new ASPECT manikin.

There is a limited amount of data currently available on the acceleration and braking performances of school buses. This paper analyzes the braking performance of various Type A and Type C school buses with hydraulic and air brakes. The effect of ABS and Non-ABS systems as well as driver experience is discussed. A comparison with passenger car braking performance is presented. The acceleration of a school bus is also presented. Evaluations of “normal” and “rapid” accelerations are presented for Type A and Type B buses. A comparison with commonly used acceleration values for various vehicles is presented.