Search Results

The WorldSID dummy can be equipped with both a pubic and a sacroiliac joint (S-I joint) loadcell. Although a pubic force criterion and the associated injury risk curve are currently available and used in regulation (ECE95, FMVSS214), as of today injury mechanisms, injury criteria, and injury assessment reference values are not available for the sacroiliac joint itself. The aim of this study was to investigate the sacroiliac joint injury mechanism. Three configurations were identified from full-scale car crashes conducted with the WorldSID 50th percentile male where the force passing through the pubis in all three tests was approximately 1500 N while the sacroiliac Fy / Mx peak values were 4500 N / 50 Nm, 2400 N / 130 Nm, and 5300 N / 150 Nm, respectively. These tests were reproduced using a 150 kg guided probe impacting Post Mortem Human Subjects (PMHS) at 8 m/s, 5.4 m/s and 7.5 m/s.

Many efforts have been made to understand the mechanism of whiplash injury. Recently, the cervical facet joint capsules have been focused on as a potential site of injury. An experimental approach has been taken to analyze the vertebral motion and to estimate joint capsule stretch that was thought to be a potential cause of pain. The purpose of this study is to analyze the kinematics of the cervical facet joint using a human FE model in order to better understand the injury mechanism. The Total Human Model for Safety (THUMS) was used to visually analyze the local and global kinematics of the spine. Soft tissues in the neck were newly modeled and introduced into THUMS for estimating the loading level in rear impacts. The model was first validated against human test data in the literature by comparing vertebrae motion as well as head and neck responses. Joint capsule strain was estimated from a maximum principal strain output from the elements representing the capsule tissues.

This paper analyzed the mechanisms of injury in high speed, right-lateral impacts of stock car auto racing, and interaction of the occupant and the seat system for the purpose of reducing the risk of injury, primarily rib fractures. Many safety improvements have been made to stock car racing recently, including the Head and Neck Support devices (HANS®), the 6-point restraint harnesses, and the implementation of the SAFER Barrier. These improvements have contributed greatly to mitigating injury during the race crash event. However, there is still potential to improve the seat structure and the understanding of the interaction between the driver and the seat in the continuation of making racing safety improvements. This is particularly true in the case of right-lateral impacts where the primary interaction is between the seat supports and the driver and where the chest is the primary region of injury.

Posterior translation of the tibia with respect to the femur can stretch the posterior cruciate ligament (PCL). Fifteen millimeters of relative displacement between the femur and tibia is known as the Injury Assessment Reference Value (IARV) for the PCL injury. Since the anterior protuberance of the tibial plateau can be the first site of contact when the knee is flexed, the knee bolster is generally designed with an inclined surface so as not to directly load the projection in frontal crashes. It should be noted, however, that the initial flexion angle of the occupant knee can vary among individuals and the knee flexion angle can change due to the occupant motion. The behavior of the tibial protuberance related to the knee flexion angle has not been described yet. The instantaneous angle of the knee joint at the timing of restraining the knee should be known to manage the geometry and functions of knee restraint devices.

The purpose of this study is to analyze the piston skirt friction reduction effect of a diamond-like carbon (DLC)-coated wrist pin. The floating liner method and elasto-hydrodynamic lubrication (EHL) simulation were used to analyze piston skirt friction. The experimental results showed that a DLC-coated wrist pin reduced cylinder liner friction, and that this reduction was particularly large at low engine speeds and large pin offset conditions. Friction was particularly reduced at around the top and bottom dead center positions (TDC and BDC). EHL simulation confirmed that a DLC-coated wrist pin affects the piston motion and reduces the contact pressure between the piston skirt and cylinder liner.

The most severe ankle skeletal injury called pilon fractures can cause long term disability and impairment. Based on previous experimental studies, the pilon fractures are regarded as caused by a high-energy compressive force in the ankle joint and affected by a muscular tension force generated by emergency braking. However, quantitative injury criteria for the pilon fractures are still unknown. More accurate prediction of bone fractures in the distal tibia using a FE model of human lower leg can help us know the quantitative injury criteria. Therefore we newly proposed an anisotropic inelastic constitutive model of cortical bone including damage evolution and then implemented it to a FE code, LS-DYNA. The proposed model successfully reproduced most of anisotropy, strain rate dependency, and asymmetry of tension and compression on material and failure properties of human femoral cortical bone.

Since 1992, Toyota Motor Corporation (TMC) has been working on the development of fuel cell system technology. TMC is designing principal components in-house, including fuel cell stacks, high-pressure hydrogen storage tank systems, and hybrid systems. TMC developed the '02 model TOYOTA FCHV, the world-first market-ready fuel cell vehicle, and started limited lease of the vehicles in 2002. In 2005, TMC developed a new model of TOYOTA FCHV which obtained vehicle type certification in Japan, and is currently available for leasing. TMC has improved the cruising range and cold start/drive capability of the TOYOTA FCHV, and conducted public road tests to evaluate the performance. The improved TOYOTA FCHV successfully traveled from Osaka to Tokyo (approximately 560km, 350 miles) on a single fueling of hydrogen. In addition, the cold weather tests carried out in Hokkaido and North America have verified its starting/driving capability at subfreezing temperatures including -37°C.

In Toyota’s 2nd generation FCV, an electric turbo-type air compressor has been adopted for downsizing and cost reduction. Automotive Fuel Cell applications present several challenges for implementing a turbo-type air compressor. When operating a fuel cell in high-temperature or high-altitude locations, the FC stack must be pressurized to prevent dry-up. The flow rate vs pressure conditions that the FC must pass through or in some cases operate at are typically within the surge region of a turbo-type air compressor. Additionally, Toyota requires quick air transient response (< 1 sec) for power generation, energy management, and FC dry-up prevention. If the turbo-type air compressor is not precisely controlled during quick transients, it can easily enter the surge region.

Toyota Motor Corporation (TMC) has been developing fuel cell (FC) technology since 1992, and finally “MIRAI” was launched in 15th Dec. 2014. An important step was achieved with the release of the “FCHV-adv” in 2008. It established major improvements in efficiency, driving range, durability, and cold start capability. However, enhancing performance and further reductions in size and cost are required to facilitate the commercial widespread adoption of fuel cell vehicles (FCVs). TMC met these challenges by developing the world's first FC stack without a humidifying system. This was achieved by the development of an innovative cell flow field structure and membrane electrode assembly (MEA), enabling a compact and high-performance FC stack. Other cost reduction measures incorporated by the FC stack include reducing the amount of platinum in the catalyst by two-thirds and adopting a carbon nano-coating for the separator surface treatment.

Cold weather operation has been a major issue for fuel cell vehicles (FCV). In order to counteract this effect on FCV operation, an approach for rapid warm-up operation based on : concentration overvoltage increase and conversion efficiency decrease by limiting oxygen or hydrogen supply, was adopted in a running fuel cell hybrid vehicle. In order to adjust the output power response of the fuel cell to the target power of the vehicle, -the inherent capacitance characteristics of the fuel cell were measured- based on the oxidation-reduction reaction and an electric double-layer capacitor, and an equivalent electric circuit model of a fuel cell with the capacitance was constructed. This equivalent electric circuit model was used to develop a power control algorithm to manage absorption of the surplus power, or deviation, to the capacitance.

Various issues must be resolved before sustainable mobility can be achieved, the most important of which are reacting to energy supply and demand, and lowering CO2 emissions. At present, the fact that the vast majority of vehicles run on conventional oil is regarded as a problem for which Toyota Motor Corporation (TMC) is developing various technological solutions. Fuel cell (FC) technology is one of the most promising of these solutions. A fuel cell is an extremely clean device that uses hydrogen and oxygen to generate power without emitting substances like CO2, NOx, or PM during operation. Its energy efficiency is high and it is widely expected to form the basis of the next generation of powertrains. Since 1992, TMC has been working to develop the main components of fuel cell vehicles, including the fuel cell itself, and the high pressure hydrogen tank and hybrid systems.

The fuel cell (FC) stack that was developed for a new FCV achieves a power density of 3.1 kW/L (one of the highest in the world) by the use of an innovative cell flow field structure, electrodes, and a simplified stack tightening structure. These innovations allow the FC stack to be installed under the floor of a sedan-type fuel cell vehicle (FCV). Underfloor installation also required excellent impact resistance, waterproofing, and rustproofing performance. These items were quantified and analyzed during the development of the FC stack, resulting in an optimized structure capable of enduring a wide range of possible underfloor inputs.

In order to improve air quality and to reduce urban noise, Toyota Motor Corporation has developed a fuel cell hybrid bus, FCHV-BUS2, in cooperation with HINO Motors, Ltd. The FCHV-BUS2 is based on a HINO low floor city bus model, and powered by a hydrogen fuel cell hybrid system. Hydrogen is stored in high pressure tanks on the bus roof. Based on the Toyota fuel cell hybrid technology for passenger cars, this fuel cell hybrid bus is equipped with two fuel cell stacks, two traction motors and four secondary batteries, making its vehicle efficiency approximately 1.7 times better than the diesel engine powered bus. The vehicle efficiency is boosted by charging the secondary batteries with regenerated energy while deceleration and by stopping the fuel cell stack(s) power generation during low fuel cell power modes.

The goal of this study was to develop injury probability functions for the leg bending moment and MCL (Medial Collateral Ligament) elongation of the Flexible Pedestrian Legform Impactor (Flex-PLI) based on human response data available from the literature. Data for the leg bending moment at fracture in dynamic 3-point bending were geometrically scaled to an average male using the standard lengths obtained from the anthropometric study, based on which the dimensions of the Flex-PLI were determined. Both male and female data were included since there was no statistically significant difference in bone material property. Since the data included both right censored and uncensored data, the Weibull Survival Model was used to develop a human leg fracture probability function.

The use of hybrid, fuel cell electric, and pure electric vehicles is on the increase as part of measures to help reduce exhaust gas emissions and to help resolve energy issues. These vehicles use regenerative-friction brake coordination technology, which requires a braking system that can accurately control the hydraulic brakes in response to small changes in regenerative braking. At the same time, the spread of collision avoidance support technology is progressing at a rapid pace along with a growing awareness of vehicle safety. This technology requires braking systems that can apply a large braking force in a short time. Although brake systems that have both accurate hydraulic control and large braking force have been developed in the past, simplification is required to promote further adoption.

If a crash prediction system (Rear pre-crash safety) determines that a rear crash is unavoidable, this product reduces whiplash injury by reducing shock to the neck by quickly moving the front part of a head restraint forward thus shortening the distance between the head and the head restraint. Pre-crash intelligent head restraint systems were developed for safe vehicle. In this paper, the method to detect collision risk and how to protect passenger's heads was introduced. Also sensor idea and operating mechanism were explained.

The new Toyota Mirai hydrogen fuel cell electric vehicle (FCEV) was launched in December 2020. Achieving a low-cost, high-performance FC stack is an important objective in FCEV development. At the same time, it is also necessary to ensure vehicle safety. This paper presents an overview of the safety requirements for onboard FC stacks. It also describes the simulation and evaluation methods for the following matters related to the FC stack. i) Impact force resistance: The FC stack was designed to prevent cell layer slippage due to impact. Constraint force between the cell layers is provided by the frictional force between the cells and an external constraint. A simulation of the behavior of the cell layers under impact force was developed. The impact force resistance was confirmed by an impact loading test. ii) Hydrogen safety: The FC stack was designed so that permeated hydrogen is ventilated and the hydrogen concentration is kept below the standard.

A few reports suggest differences in injury outcomes between cadaver tests and real-world accidents under almost similar conditions. This study hypothesized that muscle activity could primarily cause the differences, and then developed a human body finite element (FE) model with individual muscles. Each muscle was modeled as a hybrid model of bar elements with active properties and solid elements with passive properties. The model without muscle activation was firstly validated against five series of cadaver test data on impact responses in the anterior-posterior direction. The model with muscle activation levels estimated based on electromyography (EMG) data was secondly validated against four series of volunteer test data on bracing effects for stiffness and thickness of an upper arm muscle, and braced driver's responses under a static environment and a brake deceleration.

To investigate the effect of muscle activity in pre-impact on injury outcome, we developed a human arm finite element model with muscles which consisted of solid elements and truss elements that could be used for simulating muscle stiffness change for the inputted activity and 3-D geometry of each muscle. Two series of experimental tests on muscle stiffness change and arm flexion were conducted for validation of the model. Comparisons between the simulation results and test data indicated the model validity. Lateral impact simulations for a left arm demonstrated that the muscle activity in pre-impact had significant effects on the motion and stress distribution of the arm bones.

Toyota Motor Corporation (TMC) has been developing fuel cell (FC) system technology since 1992. In 2008 the Toyota "FCHV-adv" was released as part of a demonstration program. It established major improvements in key performance areas such as cold start/drive capability, efficiency, driving range, and durability. However, in order to facilitate the commercial widespread adoption of fuel cell vehicles (FCVs), improvements in performance and further reductions in size and cost were required.In December 2014, Toyota launched the world’s first commercially available fuel cell vehicle (FCV) the "Mirai" powered by the Toyota Fuel Cell System (TFCS). Simplicity, reliability and efficiency have been significantly improved within the Toyota TFCS. As a result, the Mirai has become an attractive vehicle which could lead the way towards full-scale popularization of FCVs.