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Having, by now, introduced several new vehicles that comply with FMVSS 202a, manufacturers are reporting an increased number of complaints from consumers who find that the head restraint is too close; negatively affecting their posture. It is speculated that one of the reasons that head restraints meeting the new requirement are problematic is that the FMVSS backset measurement is performed at a back angle that is more reclined than the back angle most drivers choose and the back angle at which the seat / vehicle was designed. The objective of this paper is to confirm this hypothesis and elaborate on implications for regulatory compliance in FMVSS 202a.

This paper presents the final phase of a study to develop the modeling methodology for an advanced steering assembly with a safety-enhanced steering wheel and an adaptive energy absorbing steering column. For passenger cars built before the 1960s, the steering column was designed to control vehicle direction with a simple rigid rod. In severe frontal crashes, this type of design would often be displaced rearward toward the driver due to front-end crush of the vehicle. Consequently, collapsible, detachable, and other energy absorbing steering columns emerged to address this type of kinematics. These safety-enhanced steering columns allow frontal impact energy to be absorbed by collapsing or breaking the steering columns, thus reducing the potential for rearward column movement in severe crashes. Recently, more advanced steering column designs have been developed that can adapt to different crash conditions including crash severity, occupant mass/size, seat position, and seatbelt usage.

Powerplant NVH decisions are sometimes made looking only at how the change impacts either the source radiated noise level or the source vibration. Depending on the engine configuration, those can be good approximations, but they can also be very misleading. By combining both noise sources into a vehicle equivalent noise level a much better analysis can be made of the impact of any proposed design change on the customer perceived loudness. This paper will investigate several different scenarios and identify how the airborne and the structureborne paths combine for I4, V6 and V8 engine configurations. Similar relationships will be shown for path as well as the source contributions.

As the new features for driver assistance and active safety systems are growing rapidly in vehicles, the simulation within a virtual environment has become a necessity. The current active safety system consists of Electronic Control Units (ECUs) which are coupled to camera and radar sensors. Two methods of implementation exists, integrated sensors with control modules or separation of sensors form control modules. The subsystem integration testing poses new challenges for virtual environment for simulation of active safety features. The comprehensive simulation environment for integration testing consists of chassis controls, powertrain, driver assistance, body and displays controllers. Additional complexity in the system is the serial communication strategy. Multiple communication protocols such as GMLAN, LIN, standard CAN, and Flexray could be present within the same vehicle topology.

This research examined driver acceptance and behavior associated with Speed Limit and Curve Advisor systems, including influences on speed choice. Drivers experienced messages from an emulated Speed Limit and Curve Advisor system during a 2-hour public road drive. Driver tolerance for system errors and message conflicts was also studied by manipulating the accuracy of the information provided by the system. Messages were presented using either a Head-Up Display or on an in-dash Driver Information Center. Results indicate that drivers liked having speed limit information continuously available to them while driving, but the information provided by the Speed Limit Advisor did not significantly influence or alter drivers' speed choice or deceleration profiles in comparison to driving without the system.

An analysis of the first 35 back-over crashes reported by NHTSA's Special Crash Investigations unit was undertaken with two objectives: (1) to test a hypothesized classification of backing crashes into types, and (2) to characterize scenario-specific conditions that may drive countermeasure development requirements and/or objective test development requirements. Backing crash cases were sorted by type, and then analyzed in terms of key features. Subsequent modeling of these SCI cases was done using an adaptation of the Driving Reliability and Error Analysis Methodology (DREAM) and Cognitive Reliability and Error Analysis Methodology (CREAM) (similar to previous applications, for instance, by Ljung and Sandin to lane departure crashes [10]), which is felt to provide a useful tool for crash avoidance technology development.

Alternative implementations of a Rear Cross Traffic Alert (RCTA) system intended to actively notify drivers of the presence of rear cross-path traffic when backing were evaluated in naturalistic settings. The feature is one of several emerging technologies designed to assist drivers when backing - in this case, enhancing drivers' awareness of traffic approaching from the rear. The study allowed performance under a range of RCTA system driver interface implementations to be contrasted with conventional and wide Field of View (FOV) Rear Vision systems. Evaluations were conducted using a sample of 70 drivers under naturalistic settings and environments with repeated exposures to backing tasks. The study also made use of a staged conflict situation with a confederate vehicle in order to more precisely quantify driver behavior and system usage across drivers under controlled conflict situations.

Vehicle-to-vehicle (V2V) communication systems can enable a number of wireless-based vehicle features that can improve traffic safety, driver convenience, and roadway efficiency and facilitate many types of in-vehicle services. These systems have an extended communication range that can provide drivers with information about the position and movements of nearby V2Vequipped vehicles. Using this technology, these vehicles are able to communicate roadway events that are beyond the driver's view and provide advisory information that will aid drivers in avoiding collisions or congestion ahead. Given a typical communication range of 300 meters, drivers can potentially receive information well in advance of their arrival to a particular location. The timing and nature of presenting V2V information to the driver will vary depending on the nature and criticality of the scenario.

Torque controls for the engine and electric motors in a Powersplit HEV are keys to the success of balancing fuel economy, driveability, and battery power control. The electric variable transmission (EVT) offers an opportunity to let the engine operate at system-optimal fuel efficient points independently of any load. Existing work shows such a benefit can be realized through a decentralized control structure that translates the driver inputs to independent engine torque and speed control. However, our study shows that the decentralized control structures have a fundamental limitation that arises from the nonminimum phase (NMP) zero in the transfer function from the driver power command to the generator torque change rate, and thus not only is it difficult to obtain smooth generator torque but also it can cause violations on battery power limits during transients. Additionally, it adversely affects the driveability due to the generator torque transients reflected at the ring gear.

This paper presents the implementation of an off-line optimized torque vectoring controller on an electric-drive vehicle with four in-wheel motors for driver assistance and handling performance enhancement. The controller takes vehicle longitudinal, lateral, and yaw acceleration signals as feedback using the concept of state-derivative feedback control. The objective of the controller is to optimally control the vehicle motion according to the driver commands. Reference signals are first calculated using a driver command interpreter to accurately interpret what the driver intends for the vehicle motion. The controller then adjusts the braking/throttle outputs based on discrepancy between the vehicle response and the interpreter command.

The Reverse Braking Assist (RBA) feature is designed to automatically activate full braking in a backing vehicle. When this feature activates, a backing vehicle is suddenly stopped or may slide to a stop. During this process, an understanding of the driver's behavior may be useful in the design of an appropriate human-machine-interface (HMI) for the RBA. Several experimental studies were done to examine driver behavior in response to an unexpected and automatic braking event while backing [1]. Two of these studies are reported in this paper. A 7-passenger Crossover Utility Vehicle was fitted with a rear-view camera, a center-stack mounted LCD screen, and ancillary recording devices. In the first study, an object was suddenly placed in the path of a backing vehicle. The backing vehicle came to a sudden and complete stop. The visual image of the backing path on the LCD prominently showed that an obstacle was present in the backing path of the vehicle.

The “Information Age” and the growth of electronics on vehicles are driving forces behind the “personalized” vehicle. The vision is a responsive vehicle where the powertrain, ride, instrumentation and interior can be customized by the driver. A strategy to personalize the vehicle is presented; first, through market research to identify new features, and second, ergonomic design for easy to use displays and controls. Changes in society that are driving forces are discussed along with the counter balancing need for ergonomic design. Approaches to personalization, ergonomic principles, and technologies are presented.

The battery system in the Chevrolet Volt is very complex and must balance a variety of performance criteria, including the safety of vehicle occupants and other users. In order to assure a thorough approach to battery system safety, a system safety engineering process was applied and found to provide a useful framework. This methodical approach began with the preliminary hazard analysis and continued through requirements definition, design development and, finally, validation. Potentially hazardous conditions related directly to functional safety (for example, charge control) and primary physical safety (for example, short circuit conditions) can all be addressed in this manner. Typical battery abuse testing, as well as newly defined limit testing, supported the effort. Extensive documentation, traceability and peer reviews helped to verify that all issues were addressed.

Vehicle noise and vibration (NVH) is among the important attributes of the vehicle. This attribute has to be designed for in the product development process. This produces challenges that are usually overlooked by researchers in the field. These challenges are assessed in this manuscript. The emphasis here is on the NVH phenomenon at the vehicle level. Little work is being done to study the vehicle noise and vibration from a system or customer perspective. This manuscript brings to the attention of researchers and the NVH community at large the various NVH challenges that constitute complexities to the development engineer and may deserve closer attention.

Experimental forms of two different types of engine oil viscosity sensors have been tested that use uniformly poled disks of piezoelectric PZT ceramic. In both cases, the disks were used to form electromechanical resonators functioning as the frequency-controlling element in a transistor oscillator circuit. The simpler type of sensor used only one disk, vibrating in a radial-longitudinal mode of vibration. In this mode, a disk 2.54 cm in diameter and 0.127 cm thick had a resonant frequency of approximately 90 kHz. The second type of sensor used two such disks bonded together by a conducting epoxy, with poling directions oriented in opposite directions. This composite resonator vibrated in a radially-symmetrical, flexural mode of vibration, with the lowest resonant frequency at approximately 20 kHz. The presence of tangential components of motion on the major faces of both resonators made them sensitive to the viscosity of fluids in which they were immersed.

Each more the consumer uses the vehicle noise, vibration, and harshness (NVH) attributes to define the vehicle model when purchasing a car, so the sound quality development is very important to guarantee the automaker success in a competitive market. Several vehicle components contribute to the consumer sound quality perception, as engine, gearbox and exhaust systems. So those components improvement is necessary in order to enrich the sound perception. In this article will be developed a case study that evaluates the contribution and the characteristics of the irradiated noise from the power steering system, which was classified as moan, whine and hiss noise, defines objectively each phenomena and evaluate the proposed systems.

Seat Effective Amplitude Transmissibility (SEAT) values can be obtained from direct measurements at seat track and top or estimated from transmissibility data and seat track input. Vertical transmissibility was measured for sixteen seats and six subjects on the Ford Vehicle Vibration Simulator, and these 96 functions used to estimate the seat top response for rough road input. SEAT values were calculated, and good correlation to values computed from direct seat top measurements obtained (R2 of 0.86). Averaging transmissibilities and direct seat measurements over the 6 subjects to obtain correlations for the 16 seats improved R2 to 0.94, validating this approach.

The safety and comfort aspects of passenger cars are significant sales argument and have become a topic of rising importance during the development process of a new car. The objective of this study is to compare the performance of several current model vehicles, highlight the drawbacks of current defrosting/demisting systems and point the way to improved passive mechanisms. The investigation is experimental. The experiments are carried out using full-scale current vehicle models. The results show that the current designs of the defroster nozzle give maximum airflow rates in the vicinity of the lower part of the windshield, which decrease gradually towards the upper parts of the windshield. This hinders and limits the vision of the driver, particularly at the top of the windshield, which can be uncomfortable and indeed dangerous.

Seat belts are the primary occupant-protection devices for vehicle crashes. Field statistics show that proper usage of seat belts substantially contributes to decreases in the fatality rate and injury level. To collect first-hand information regarding seat belt comfort and usability, a questionnaire survey was conducted. The most significant problems were found as belt trapping in the door, awkward negotiating with clothes, belt twisting, belt locking up, and difficulty to locate the buckle. The survey results indicated that drivers who are over 40 years old have more complaints than younger drivers. When the driver's age increases to 55 and above, belt pulling force and inappropriate and loose fitting of the belt on the body become major issues. Female drivers have more complaints than male drivers. Short statured drivers need both hands to pull and guide the retracting of the belt.

In this study, US and UK accident data were analyzed to identify parameters that may influence rollover propensity to analyze driver injury rate. The US data was obtained from the weighted National Automotive Sampling System (NASS-CDS), calendar years 1992 to 1996. The UK pre-roll data was obtained from the national STATS 19 database for 1996, while the injury information was collected from the Co-operative Crash Injury Study (CCIS) database. In the US and UK databases, rollovers accounted for about 10% of all crashes with known crash directions. In the US and UK databases, most rollovers occurred when the vehicle was either going straight ahead or turning. The propensity for a rollover was more than 3 times higher when going around a bend than a non-rollover. In the UK, 74% of rollovers occurred on clear days with no high winds and 14% on rainy days with no high winds. In the US, 83% of rollovers took place in non-adverse weather conditions and 10% with rain.