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The goal of the present study was to develop a new legform impactor that accurately represents both the impact force (i.e., force between the leg and impacting mass)and leg kinematics in lateral impacts simulating car-pedestrian accidents. In its development we utilized the knee joint of the pedestrian dummy called Polar-2 (HONDA R&D) in which the cruciate and collateral ligaments are represented by means of springs and cables, the geometry of the femoral condyles is simplified using ellipsoidal surfaces, and the tibial meniscus is represented by an elastomeric pad. The impactor was evaluated by comparing its responses with published experimental results obtained using postmortem human subjects (PMHS). The evaluation was done under two conditions: 1)impact point near the ankle area (bending tests),and 2)impact point 84 mm below the knee joint center (shearing tests). Two impact speeds were used: 5.56 m/s and 11.11 m/s.

ISO26262 was intended only for passenger cars but can be applied to motorcycles if the Controllability (C) is subjectively evaluated by expert riders. Expert riders evaluate motorcycle performance from the viewpoint of ordinary riders. However, riding maneuvers of ordinary riders have not been confirmed by objective data. For this reason, it is important to understand the basic characteristics of riding maneuvers of both expert and ordinary riders. This study seeks to confirm the compatibility between the riding maneuvers of expert riders and those of ordinary riders. The riding maneuvers and vehicle behavior of four expert riders and 16 ordinary riders were compared using the results of a test assuming normal running.

To model sprays from pintle type nozzles with large hollow cone angle and high injection pressure, the correct flow field in the near region must be predicted. A new model was implemented in KIVA-3V code, which adopts the theory of steady gas jet to correct the relative velocities between the drop and gas phases, based on the existence of quasi-steady part of the conical spray and an assumption of equivalent gas jet. Accordingly, the structure of the sprays is defined into three parts: 1. initial part that the gas phase velocity is set to the assumed gas injection velocity; 2. quasi-steady part where the component of velocity in the symmetric line direction of the spray is corrected; 3. stagnation part which is left unchanged. This new model is referred to as the Relative Velocity Correction (RVC) model, and is a set of empirical equations that calculate the sectional distribution of the gas-phase velocity along the symmetric line of the sprays.

Evaluation of car front aggressiveness in car-pedestrian accidents is typically done using sub-system tests. Three such tests have been proposed by EEVC/WG17: 1) the legform to bumper test, 2) the upper legform to bonnet leading edge test, and 3) the headform to bonnet top test. These tests were developed to evaluate performance of the car structure at car to pedestrian impact speed of 11.1 m/s (40 km/h), and each of them has its own impactor, impact conditions and injury criteria. However, it has not been determined yet to what extent the EEVC sub-system tests represent real-world pedestrian accidents. Therefore, there are two objectives of this study. First, to clarify the differences between the injury-related responses of full-scale pedestrian dummy and results of sub-system tests obtained under impact conditions simulating car-to-pedestrian accidents. Second, to propose modifications of current sub-system test methods. In the present study, the Polar (Honda R&D) dummy was used.

The demands of application of dual-axis chassis dynamometers (4WD-CHDY) have increased recently due to the improvement of performance of 4WD-CHDY and an increase in the number of 4WD vehicles which are difficult to convert to 2WD. However, there are few evaluations of any differences between fuel economy and exhaust emission levels in the case of 2WD-CHDY with conversion from 4WD to 2WD (2WD-mode) and 4WD-CHDY without conversion to 2WD (4WD-mode). Fuel economy and exhaust emission tests of 4WD vehicle equipped with a typical 4WD mechanism were performed to investigate any differences between the case of the 2WD-mode and the 4WD-mode. In these tests, we measured ‘work at wheel’ (wheel-work) using wheel torque meters. A comparison of the 2WD-mode and the 4WD-mode reveals a difference of fuel economy (2WD-mode is 1.5% better than that of 4WD-mode) and wheel-work (2WD-mode is 3.9% less than that of 4WD-mode). However, there are almost no differences of exhaust emission levels.

For applying ISO 26262 to motorcycles, controllability classification (C class evaluation) by expert riders is considered an appropriate technique. Expert riders have evaluated commercial product development for years and can appropriately conduct vehicle tests while observing safety restrictions (such as avoiding the risk of falling). Moreover, expert riders can ride safely and can stably evaluate motorcycle performance even if the test conditions are close to the limits of vehicle performance. This study aims to construct a motorcycle C class evaluation method based on an expert rider’s subjective evaluation. On the premise that expert riders can rate the C class, we improved a test procedure that used a subjective evaluation sheet as the concrete C class evaluation method for an actual hazardous event.

The SAE Fuel Cell Vehicle (FCV) Safety Working Group has been addressing FCV safety for over 9 years. The initial document, SAE J2578, was published in 2002. SAE J2578 has been valuable as a Recommended Practice for FCV development with regard to the identification of hazards and the definition of countermeasures to mitigate these hazards such that FCVs can be operated in the same manner as conventional gasoline internal combustion engine (ICE)-powered vehicles. SAE J2578 is currently being revised so that it will continue to be relevant as FCV development moves forward. For example, test methods were refined to verify the acceptability of hydrogen discharges when parking in residential garages and commercial structures and after crash tests prescribed by government regulation, and electrical requirements were updated to reflect the complexities of modern electrical circuits which interconnect both AC and DC circuits to improve efficiency and reduce cost.

An impact test procedure with a legform addressing lower limb injuries in car-pedestrian accidents has been proposed by EEVC/WG17. Although a high frequency of lower limb fractures is observed in recent accident data, this test procedure assesses knee injuries with a focus on trauma to the ligamentous structures. The goal of this study is to establish a methodology to understand injury mechanisms of both ligamentous damages and bone fractures in car-pedestrian accidents. A finite element (FE) model of the human lower limb was developed using PAM-CRASH™. The commercially available H-Dummy™ lower limb model developed by Nihon ESI for a seated position was modified to represent the standing posture of pedestrians. Mechanical properties for both bony structures and knee ligaments were determined from our extensive literature survey, and were carefully implemented in the model considering their strain rate dependency in order to simulate the dynamic response of the lower limb accurately.

The European Enhanced Vehicle-Safety Committee (EEVC) has proposed a test procedure to assess the protection vehicles provide to the lower extremity of pedestrians during a collision. This procedure utilizes a legform impactor developed by the Transport Research Laboratory (TRL). However, the TRL Pedestrian Legform Impactor (TRL-PLI) is composed of rigid long bones (cannot simulate the bone flexibility of the human) and rather stiff knee joint. The differences lead to a lack of biofidelity of the TRL-PLI, i.e., unnaturally stiff responses are observed. This study develops a biofidelic Flexible Pedestrian Legform Impactor (Flex-PLI) that can simulate human bone flexibility and human knee joint stiffness properly. The Flex-PLI can also measure many of the injury parameters, long bone strains at multiple locations, knee ligament elongations, and the compression forces between the femoral condyles and tibial plateau in comparison to the TRL-PLI.

In 1999, some Japanese fuel suppliers sold highly concentrated alcohol fuels, which are mixtures of gasoline and oxygenates, such as alcohol or ether, in amounts of 50% or more. In August 2001, it was reported that some vehicle models using the highly concentrated alcohol fuels encountered fuel leakage and vehicle fires due to corrosion of the aluminum used for the fuel-system parts. The Ministry of Economy, Trade and Industry (METI) and the Ministry of Land, Infrastructure and Transport Government of Japan (MLIT) jointly established the committee on safety for highly concentrated alcohol fuels in September 2001. The committee consisted of automotive technology and metal corrosion experts knowledgeable about preventing such accidents and ensuring user safety. Immersion tests were conducted on metals and other materials used for the fuel-supply system parts to determine the corrosion resistance to each alcohol component contained in the highly concentrated alcohol fuels.

Tapered FRP tubes have high-energy absorption performance under axial compressive load. FRP will be useful for structural material of a shock absorber in the various industries. And in order to simulate the behavior of this material, several experimental tests and numerical simulations using FEM have been carried out recently. However, it is still difficult to simulate the behavior of tapered FRP tubes involving so called “Progressive Crushing” with FEM properly, because the fracture mechanism contains various kinds of fractures such as delamination, fiber fracture and so on. In this study, we proposed a specially designed FEM model based that is useful for the crush-worthiness analysis of FRP tube.

The SAE Fuel Cell Vehicle (FCV) Safety Working Group has been addressing FCV safety for over 11 years. In the past couple of years, significant attention has been directed toward a revision to the standard for vehicular hydrogen systems, SAE J2579(1). In addition to streamlining test methodologies for verification of Compressed Hydrogen Storage Systems (CHSSs) as discussed last year,(2) the working group has been considering the effect of vehicle fires, with the major focus on a small or localized fire that could damage the container in the CHSS and allow a burst before the Pressure Relief Device (PRD) can activate and safely vent the compressed hydrogen stored from the container.

Controllability is defined in ISO 26262 as a driver’s ability to avoid a specified harm caused by a malfunction of electrical and electronic systems installed in road vehicles. According to Annex C of Part 12 of ISO 26262, simulation is one of the techniques that the Controllability Classification Panel (CCP) can use to evaluate comprehensively the controllability class (C class) of motorcycles. With outputs of (i) an index for the success of harm avoidance and (ii) the magnitude of the rider’s compensatory control action required to avoid harm, the simulation is useful for evaluating the C class of the degrees of malfunction that cannot be implemented in practice for the sake of the test rider’s safety. To aim at supplying data that the CCP can use to judge the C class, we try to estimate the vehicle behavior and a rider’s compensatory control actions following a malfunction using vehicle dynamics simulations.

ISO 26262, a functional safety standard for motor vehicles, was published in November 2011. Although motorcycles are not included in the scope of application of the current edition of ISO 26262, it is expected that motorcycles will be included in the next revision. However, it is not appropriate to directly apply automotive safety integrity levels (ASILs) to motorcycles because the situation of usage in practice presumably differs between motorcycles and motor vehicles. In our previous study, we newly defined safety integrity levels for motorcycles (MSILs) and proposed that the levels of MSILs should correspond to levels one step lower than those of ASILs; however, we did not investigate the validity of their connections. Accordingly, in this research, we validated the connections. We defined the difference of levels of SILs between motorcycles and motor vehicles as the difference of target values of random hardware failure rates specified in ISO 26262-5.

Test procedures to assess vehicle compatibility were investigated based on a series of crash tests. Structural interaction and compartment strength are significant for compatibility, and full-width tests and overload tests have been proposed to assess these key factors. Full-width rigid and deformable barrier test results were compared with respect to force distributions, structural deformation and dummy responses. In full-width deformable tests, forces from structures can be clearly shown in barrier force distributions. The average height of force (AHOF) determined in full rigid and deformable barrier tests were similar. From car-to-car tests, it was demonstrated that stiffening the compartment of small cars is an effective and direct way to improve compatibility. To evaluate the compartment strength, five overload tests were carried out. The rebound force is proposed as a compartment strength criterion.

In applying the ISO 26262 controllability classification for motorcycles in actual riding tests, a subjective evaluation by expert riders is considered to be the appropriate approach from the viewpoint of safety. We studied the construction of an expert-rider-based C class evaluation method for motorcycles and developed some evaluation test cases reproducing various hazardous events. We determined that it was necessary to accumulate more evaluation cases for further representative scenarios and that, to avoid variations in such evaluations, a method in which different expert riders can carry out testing following a common understanding had to be devised. Considering these problems for practical application, this study aimed at establishing an actual riding test method for C class evaluation by expert riders and to develop a deeper understanding of test procedures and management.

The objective of this study is to improve tire hydroplaning performance by examining the arrangement of the tread grooves, based on water flow. It is important to smoothly channel the water through the tread grooves to improve performance. For this purpose, flow around the tire contact area was visualized by particle tracing. The velocity and the direction of flow in front of the contact area became clear as a vector map. This vector map indicated that the direction of the flow depends primarily on the lateral position, i.e., the distance from the tread center. Tread grooves parallel to the flow vector were designed based on this result. The visualization of the improved tire demonstrated that water flowed smoothly along the grooves. In addition, a drum test indicated increased cornering force at high speed.

Ferrocene is used as an antiknock additive to replace lead alkyls. To clarify the influence of one metal additive, ferrocene, on engine, following experiments were carried out. The insulation resistance of spark plugs was measured, deposits in the engine were analyzed, and an exhaust emission and fuel economy tests were conducted using gasoline containing ferrocene. The deposit, which contained iron oxides, adhered to the combustion chamber, spark plugs, and exhaust pipe when the engine operated with gasoline containing ferrocene. When vehicles operated with gasoline containing ferrocene, fuel consumption increased and the exhaust temperature rose. In addition, an abnormal electrical discharge pattern was observed in spark plugs operating at high temperatures. Iron-oxide of Fe3O4 is changed into Fe2O3 under high temperatures. Discharge current flows in iron oxides including Fe2O3 because the conductivity of Fe2O3 increases at high temperatures.

Current legform impact test methods using the FlexPLI have been developed to protect pedestrians from lower limb injuries in collisions with low-bumper vehicles. For this type of vehicles, the influence of the upper body on the bending load generated in the lower limb is compensated by setting the impact height of the FlexPLI 50 mm above that of pedestrians. However, neither the effectiveness of the compensation method of the FlexPLI nor the influence of the upper body on the bending load generated in the lower limb of a pedestrian has been clarified with high-bumper vehicles. In this study, therefore, two computer simulation analyses were conducted in order to analyze: (1) The influence of the upper body on the bending load generated in the lower limb of a pedestrian when impacted by high-bumper vehicles and (2) The effectiveness of the compensation method for the lack of the upper body by increasing impact height of the FlexPLI for high-bumper vehicles.

Clarifying the impact of ETBE 8% blended fuel on current Japanese gasoline vehicles, under the Japan Clean Air Program II (JCAPII) we conducted exhaust emission tests, evaporative emission tests, durability tests on the exhaust after-treatment system, cold starting tests, and material immersion tests. ETBE 17% blended fuel was also investigated as a reference. The regulated exhaust emissions (CO, HC, and NOx) didn't increase with any increase of ETBE content in the fuel. In durability tests, no noticeable increase of exhaust emission after 40,000km was observed. In evaporative emissions tests, HSL (Hot Soak Loss) and DBL (Diurnal Breathing Loss) didn't increase. In cold starting tests, duration of cranking using ETBE 8% fuel was similar to that of ETBE 0%. In the material immersion tests, no influence of ETBE on these material properties was observed.