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Technical Paper

Development and Validation of the Finite Element Model for the Human Lower Limb of Pedestrians

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.
Technical Paper

Management System for Continuously Variable Valve Lift Gasoline Engine

A continuously variable valve lift gasoline engine can improve fuel consumption by reducing pumping loss and increase maximum torque by optimizing valve lift and cam phase according to engine speed. In this research, a new control system to simultaneously ensure good driveability and low emissions was developed for this low fuel consumption, high power engine. New suction air management through a master-slave control made it possible to achieve low fuel consumption and good driveability. To regulate the idle speed, a new controller featuring a two-degree-of-freedom sliding-mode algorithm with cooperative control was designed. This controller can improve the stability of idle speed and achieve the idle operation with a lower engine speed. To reduce emissions during cold start condition, an ignition timing control was developed that combine I-P control with a sliding mode control algorithm.
Technical Paper

Liquid Phase Thermometry of Common Rail Diesel Sprays Impinging on a Heated Wall

An experimental study was carried out on visualization of liquid phase temperature distributions in high-pressure diesel sprays impinging on a heated wall. Naphthalene/TMPD-exciplex fluorescence method and pyrene-excimer fluorescence method were utilized for the thermometry. The sprays were injected into a high-pressure and high-temperature gaseous environment. The nozzle hole diameter was 0.100 mm or 0.139 mm. The results showed that cool pockets were formed at the tip and in the impinging part of the sprays. The spray for the nozzle with 0.100 mm hole was heated up faster near the nozzle than for the nozzle with 0.139 mm hole.
Technical Paper

Experimental Evaluation of Test Procedures for Frontal Collision Compatibility

This paper investigates test procedures for vehicle frontal crash compatibility. Both Full Width Deformable Barrier (FWDB) tests and Moving Deformable Barrier (MDB) tests were studied to assess relevant factors of compatibility issues. The FWDB test with load cells was examined to evaluate the stiffness and interaction areas of vehicles (sometimes referred to as the “aggressivity” of vehicles). Compatibility metrics were computed using barrier load cell data and the output from the FWDB test was compared with that from the Full Width Rigid Barrier (FWRB) test. Since the results obtained from these two full width tests were considerably different, a full frontal vehicle-to-vehicle test was carried out to identify structural deformation modes. The results indicated that similar deformation modes were observed between the vehicle-to-vehicle test and the FWDB test.
Journal Article

Application of Electric Servo Brake System to Plug-In Hybrid Vehicle

An electric servo brake system applied for use on electric vehicles was applied for use on plug-in hybrid vehicles in order to achieve fuel-savings together with good brake feel and enhanced operability for plug-in hybrid vehicles. The electric servo brake system is made up of highly accurate braking pressure control that functions cooperatively with regenerative brakes together with a structure in which pedal force is not influenced by braking pressure control. The configuration of these components enabled good braking feel even when the power train was being switched from one drive mode to another. Automated pressurization functions that are intended for plug-in hybrid vehicles and that operate with electric servo brake systems were also developed. These developed functions include stall cooperative control that functions cooperatively with the power train, regenerative coordinate adaptive cruise control, and hill-start assist.
Technical Paper

Development of Lithium-Ion-Battery System for Hybrid System

A battery module structure and a battery management system that is optimal for the structure were developed, in order to facilitate the work of equipping hybrid cars with lithium-ion batteries (LIBs) that are expected to improve vehicle performance. This paper describes the structure of the LIB and the battery management system that is optimal for it. The battery module structure has cells with a sturdy holding structure and a highly efficient cooling system. The structure has enabled the improvement of battery pack system power output by 80% per unit weight and by 20% per unit volume compared to the previous model. The optimal management system prevents battery overcharge by detecting and controlling the state of charge (SOC) of each cell with a high degree of accuracy.
Journal Article

Detect the Imperceptible Drowsiness

Prediction of drowsiness based on an objective measure is demanded in machine and vehicle operations, in which human error may cause fatal accidents. Recently, we focused on the pupil which is controlled by the autonomic nervous system, easily and non-invasively observable from the outside of the body. Prior to the large low frequency pupil-diameter fluctuation, which is known to associate with drowsiness, a Gradual Miosis was observed in most subjects. During this miosis period, the subjects were not yet aware of their drowsiness. We have developed a software system which automatically detects the Gradual Miosis in real time.
Journal Article

Development of the Methodology for FCV Post-crash Fuel Leakage Testing Incorporated into SAE J2578

This paper explains the new methodology for post-crash fuel leakage testing of Fuel Cell Vehicles (FCVs) and other hydrogen vehicles utilizing compressed hydrogen storage systems. This methodology was incorporated into SAE J2578 that was revised and published in January, 2009. The new methodology is based on the concept in FMVSS 303 that specifies post-crash fuel leakage test method and criteria for CNG vehicle and adopted some modifications. Specifically, the following items are addressed: (1) Allowable leakage can be accurately evaluated in test even with large size tank that obtains only small pressure drop when a given amount of leakage occurs. A new method to deal with the influence of measurement errors was devised. (2) Even though only one option of test gas and initial filling pressure is accepted in FMVSS 303, new methodology for hydrogen system allows helium and hydrogen at reduced pressure as alternatives in addition to hydrogen at service pressure.
Technical Paper

The Validity of EPS Control System Development using HILS

In recent years, the increased use of electric power steering in vehicles has increased the importance of issues such as making systems more compact and lightweight, and dealing with increased development man-hours. To increase development efficiency, the use of a “Hardware in the loop simulator” (HILS) is being tested to shift from the previous development method that relied on a driver's subjective evaluation in an actual vehicle test to bench-test development. Using HILS enables tasks such as specification studies, performance forecasts, issue identification and countermeasure proposals to be performed at an early stage of development even when there is no prototype vehicle. This report describes a case study of using HILS to solve the issues of reducing the load by adjusting the geometric specifications around the kingpin and eliminating the tradeoff by adding a new EPS control algorithm in order to make the electric power steering (EPS) more compact and lightweight.
Journal Article

Advanced Control System of Variable Compression Ratio (VCR) Engine with Dual Piston Mechanism

A dual piston Variable Compression Ratio (VCR) engine has been newly developed. This compact VCR system uses the inertia force and hydraulic pressure accompanying the reciprocating motion of the piston to raise and lower the outer piston and switches the compression ratio in two stages. For the torque characteristic enhancement and the knocking prevention when the compression ratio is being switched, it is necessary to carry out engine controls based on accurate compression ratio judgment. In order to accurately judge compression ratio switching timing, a control system employing the Hidden Markov Model (HMM) was used to analyze vibration generated during the compression ratio switching. Also, in order to realize smooth torque characteristics, an ignition timing control system that separately controls each cylinder and simultaneously performs knocking control was constructed.
Journal Article

Incoming Wave Estimation Characteristics by MUSIC Method Using a Virtual Array Antenna in Urban Reception Conditions

We developed “Two-Stage Method” that makes it possible to evaluate the automotive suitability of FM receivers by generating a virtual radio wave environment on a PC. The major technological challenge for the Two-Stage Method was reproducing an actual radio wave environment on PC. It was necessary to estimate the characteristics of the FM radio wave environment in tests using the Multiple Signal Classification (MUSIC) method. However, when the MUSIC method is applied to FM reception, restrictions in factors including the number of array antenna elements and the occupied bandwidth result in issues of separation performance in relation to multipath waves in urban environments. We therefore developed a MUSIC Method using a virtual array antenna, making it possible to create combinations of numbers of array and sub-array elements as desired, thus boosting multipath wave separation performance. This development was reported at the 2015 SAE World Congress.
Journal Article

Development and Application of FM Multipath Distortion Rate Measurement System Using a Fading Emulator Based on Two-Stage Method

The suitability of FM radio receivers for automobiles has conventionally been rated by evaluating reception characteristics for broadcast waves in repeated driving tests in specific test environments. The evaluation of sound quality has relied on the auditory judgment due to difficulties to conduct quantitative evaluations by experiments. Thus the method had issues in terms of the reproducibility and objectivity of the evaluations. To address these issues, a two-stage method generating a virtual radio wave environment on a PC was developed. The research further defined the multipath distortion rate, MDr, as an index for the sound quality evaluation of FM receivers, and the findings concerning the suitability of the evaluation of FM terminals for automobiles were reported at the 2015 SAE World Congress.
Journal Article

Positioning Simulation Using a 3D Map and Verification of Positional Estimation Accuracy in Urban Areas Using Actual Measurement

Positional accuracy of GPS measurement has been based on simulation and actual measurement due to the difficulty of conducting 24-hour actual running tests. However, the conventional measurement is only based on brief evaluation; hence variability of positional accuracy which varies depending on measurement time and location had been an issue. Thus, it is significant to show the validity by the estimation of positional accuracy, and actual measurement using of lengthy simulation. In this study, actual measurement data in an urban area was obtained for long hours, and a simulation using 3D maps was implemented. A high precision positional measurement system was equipped on a vehicle in order to collect actual measurements and positional data at each measurement time. The data obtained by the measurement system was used as the reference coordinate for both the simulation and the actual measurements.
Journal Article

Development of a New Two-Motor Plug-In Hybrid System

A highly efficient two-motor plug-in hybrid system is developed to satisfy the global demands of CO2 reduction. This system switches three operation modes, what is called “EV Drive”, “Hybrid Drive” and “Engine Drive”, to maximize fuel efficiency according to the driving condition of the vehicle. Practical plug-in EV (Electric Vehicle) capability is also realized by adding a high-power on-board charger and a high capacity Li-ion battery to the original system. The outlines of the system components including a newly developed Atkinson cycle engine, a highly efficient electric coupled CVT (Continuously Variable Transmission) with built-in motor and generator, an integrated PCU (Power Control Unit) and an exclusive battery for plug-in HEV (Hybrid Electric Vehicle) are described in this paper. In addition to the switching of three driving modes and the efficiency improvement of each device, cooperative control of the hybrid system is introduced.
Journal Article

Field Validation of the MC Default Fill Hydrogen Fueling Protocol

Appendix H of the SAE J2601 standard defines a development hydrogen fueling protocol named the MC Default Fill, which builds upon the foundation of the table based protocol, utilizing the same assumptions, boundary conditions, and process limits as the current standard. The MC Default Fill facilitates the following beyond the table based protocol: 1) the potential to provide faster, more consistent fueling times for fuel cell electric vehicle customers, and 2) the ability to continuously and dynamically adjust to a wide range of dispenser fuel delivery temperatures, allowing for more flexibility in station design. Computer simulations and laboratory bench tests were previously conducted and documented, validating the function and operation of the protocol.
Journal Article

Study of Reproducibility of Pedal Tracking and Detection Response Task to Assess Driver Distraction

We have developed a bench test method to assess driver distraction caused by the load of using infotainment systems. In a previous study, we found that this method can be used to assess the task loads of both visual-manual tasks and auditory-vocal tasks. The task loads are assessed using the performances of both pedal tracking task (PT) and detection response task (DRT) while performing secondary tasks. We can perform this method using simple equipment such as game pedals and a PC. The aim of this study is to verify the reproducibility of the PT-DRT. Experiments were conducted in three test environments in which test regions, experimenters and participants differed from each other in the US, and the test procedures were almost the same. We set two types of visual-manual tasks and two types of auditory-vocal tasks as secondary tasks and set two difficulties for each task type to vary the level of task load.
Technical Paper

Analysis of FM Multipath Distortion using Two-Stage and MUSIC Methods

Traditionally, the suitability of wireless terminals for automotive use has been evaluated by conducting repeated driving tests in actual environments. However, this method of evaluation has long presented issues, and the implementation of the method itself is today becoming increasingly challenging. A method of evaluating the suitability of terminals for onboard use by generating virtual radio wave environments on a PC has therefore been developed by applying a two-stage method to multiple-input multiple-output (MIMO)-over-the-air(OTA) evaluation. The radio wave propagation characteristics necessary for the generation of these virtual radio wave environments are set using the multiple signal classification method incorporating an RF recorder. The research discussed in this paper used these methods to analyze the effect of the multipath distortion rate on sound quality in the reception of FM broadcasts.
Technical Paper

The Effects of Impurities on the Corrosion Behavior of Iron in Methanolic Solutions

The electrochemical and corrosion behavior of metals in aqueous environments has received substantial attention. However, relatively little work has been devoted to the electrochemistry and corrosion of metals in non-aqueous environments. Now, with greater pressures to increase fuel efficiencies and decrease exhaust emissions, alternatives and additives to gasoline (including methanol and ethanol) are receiving increased attention from government agencies and automobile manufacturers. Unfortunately, fundamental studies of the corrosion behavior of metals in these solutions are scarce. The objective of the present work is to investigate the electrochemical and corrosion behavior of iron in methanolic solutions containing Cl, H+, SO42-, and H2O. To accomplish this, a full factorial design test matrix was developed to systematically evaluate the effects of these impurities on the corrosion behavior of iron.
Technical Paper

Robust Design on Adhesive Material and Bonding Process for Automotive Battery Pack

Adhesive bonding is a key technology for the lighter weight of battery pack trays using aluminum material. A robust design method of adhesive bonding with the required strength for battery pack structure after degradation was developed to minimize variability of strength under various noise conditions. The parameter design based on Taguchi methods determined the optimum adhesive condition of the bonding process. To guarantee strength after degradation, it is essential to select a robust adhesive material and to minimize the strength variation derived from the adhesive material. The functional evaluation, which includes experimental design method, determined adhesive material with the minimum strength variation among material candidates. Then, robustness of the adhesive material itself has been evaluated as the result of collaboration with the adhesive material supplier. This analysis was able to regulate the compound ratio of raw materials without reducing the adhesive strength.
Technical Paper

Research of Atomization Phenomena in HPDC-Step 1 Feature of Gas Porosity Dispersion and Photography of Atomized Flow

In recent years, studies have been conducted on the relationship between the J factor, which indicates flow of molten aluminum at the time of injection, and the quality of HPDC products. The flow of molten metal at a high J factor is referred to as “Atomized Flow.” The authors and others conducted studies on the relationship between the J factor and the strength of HPDC products. An area exceeding 300MPa was found in the product produced at a high J factor corresponding to the “Atomized Flow.” The defect was less in the above-mentioned position because the gas porosity was finely dispersed. Considering that the fine dispersion of gas porosity is related to the “Atomized Flow”, pictures were taken to analyze “Atomized Flow.” The molten aluminum was ejected into an open space at a high speed and the splashed conditions were photographed. From the images taken by the pulse laser permeation, the conditions of microscopic atomized flow were observed precisely.