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Characteristics of mass emission of unburned Oil-Particulate Matter and polycyclic aromatic hydrocarbons from two-stroke scooter were investigated. The tests were carried out under with and without oxidation catalyst and various air-fuel ratio ranging from 12 to 16 at 50:1 of fuel-oil mixing ratio for easy sampling. Unburned Oil-Particulate Matter and 4- to 7-rings polycyclic aromatic hydrocarbons were trapped on filter. These compounds were analyzed by high performance liquid chromatography with fluorescence detector. Mass emission of polycyclic aromatic hydrocarbons and unburned Oil-Particulate Matter tends to decrease as air-fuel ratio which increased up to stoichiometric ratio. The highest conversion ratio of unburned Oil-Particulate Matter on the oxidation catalyst was 64%. Conversion ratio of polycyclic aromatic hydrocarbons increased as rings are smaller.

As an index to control the heat release of auto-ignition combustion, our previous paper introduced a concept of ΔT. It was the difference between the adiabatic flame temperature and the initial in-cylinder gas temperature before the heat release, i.e., ΔT physically represents the heat capacity of the in-cylinder gases relative to the calorific value supplied in a cycle. Firing tests of a four-stroke auto-ignition gasoline engine revealed that the heat release process could be successfully controlled when ΔT was maintained at a proper level. This paper evolved the ΔT theory into the every possible gas exchanging state in the four-stroke engines and found out a chain of the low-temperature combustion cycle (LTC), which continuously varied from the spark-ignition (SI) to auto-ignition (AI). By using a hydraulic-electromagnetic fully-free valve actuator system, the LTC was examined in our 650 cm₃ single-cylinder experimental-engine.

By using a four-stroke gasoline engine equipped with a fully variable valve operation system, combustion performance was investigated from the aspect of a gas exchanging difference at various internal exhaust gas recirculation conditions due to the negative valve overlap variations. The in-cylinder gas temperature throughout the cycle process was analyzed thermodynamically. The experimental data revealed that in-cylinder gas temperature at the end of compression stroke (TAI) dominates the onset of autoignition and ΔT, which is an index that represents the heat capacity of the working gas, dominates the heat release of auto-ignition. This paper intends to evolve the experimental knowledge to an engineering tool, which could predict possibilities and limits of auto-ignition. As a result, a controlling mechanism of auto-ignition is proposed. According to this mechanism, a possible maximum load of auto-ignition operation is estimated and also demonstrated in the engine experiments.

Compared to conventional injection techniques, Gasoline Direct Injection (GDI) has a lot of advantages such as increased fuel efficiency, high power output and low emission levels, which can be more accurately controlled. Therefore, this technique is an important topic of today's injection system research. Although the operating conditions of GDI injectors are simpler from a numerical point of view because of smaller Reynolds and Weber numbers compared to Diesel injection systems, accurate simulations of the breakup in the vicinity of the nozzle are very challenging. Combined with the complications of experimental techniques that could be applied inside the nozzle and at the nozzle exit, this is the reason for the lack of understanding the primary breakup behavior of current GDI injectors.

The non-physiological motions of human cervical vertebrae were analyzed in volunteer tests for rear-end impacts and were considered to be an important parameter for neck injuries. The objectives of this study are to improve the Marko de Jager neck model using volunteer test data and to analyze the influence of horizontal and vertical accelerations on cervical vertebral motion. In the beginning of this study, a neck model was positioned based on X-ray cineradiography of a volunteer. Motions of each vertebra were compared with those of volunteer test data for low speed rear-end impacts (4, 6, 8km/h). In these comparisons, the differences of vertebrae motions between the neck model and the volunteer tests were found. To improve the validity of the neck model, the connection properties and the bending properties of the upper and lower vertebrae of the model were modified to increase rigidity.

To find an ignition and combustion control strategy in a gasoline-fueled HCCI engine equipped with the BlowDown SuperCharging (BDSC) system which is previously proposed by the authors, a one-dimensional HCCI engine cycle simulator capable of predicting the ignition and heat release of HCCI combustion was developed. The ignition and the combustion models based on Livengood-Wu integral and Wiebe function were implemented in the simulator. The predictive accuracy of the developed simulator in the combustion timing, combustion duration and heat release rate was validated by comparing to experimental results. Using the developed simulator, the control strategy for the engine operating mode switching between HCCI and SI combustion was explored with focus attention on transient behaviors of air-fuel ratio, A/F, and gas-fuel ratio, G/F.

Researchers concerned with motorcycle occupant protection have attempted to develop ways to protect the motorcycle occupant from injury. In the hope of finding a means to protect the motorcycle occupant's lower extremities, the authors have investigated past research, designed a device that incorporates an energy-absorbing component, tested the device in a series of collisions with automobiles, and performed an analysis of the test results to assess the merits of the new device. Results show that although the device may under certain circumstances reduce lower leg injuries, there may be increased potential for upper leg, chest, and head injuries

The purpose of this study was to investigate how autoignition leads to the occurrence of pressure oscillations. That was done on the basis of in-cylinder visualization and analysis of flame images captured with a high-speed camera using an optically accessible engine, in-cylinder pressure measurement and measurement of light emission from formaldehyde (HCHO). The results revealed that knocking intensity tended to be stronger with a faster localized growth speed of autoignition. An investigation was also made of the effect of exhaust gas recirculation (EGR) as a means of reducing knocking intensity. The results showed that the application of EGR advanced the ignition timing, thereby reducing knocking intensity under the conditions where knocking occurred.

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.

To investigate the events that could arise when fighting fires in vehicles with carbon fiber reinforced plastic (CFRP) hydrogen storage cylinders, we conducted experiments to examine whether a hydrogen jet diffusion flame caused by activation of the pressure relief device (PRD) can be extinguished and how spraying water influences the cylinder and PRD. The experiments clarified that the hydrogen jet flame cannot be extinguished easily with water or dry powder extinguishers and that spraying water during activation of the PRD may result in closure of the PRD, but is useful for maintaining the strength of CFRP composite cylinders for vehicles.

A simulation has been developed at the Japan Automobile Research Institute to predict the fuel economy of HEVs, which are currently being developed in the advanced clean energy vehicle research and development project of MITI/NEDO (ACE Project). The ACE Project includes six types of HEV. The effect of hybrid components efficiency on fuel economy was evaluated by sensitivity coefficient. The results show that the fuel economy of HEVs can improve that of the base vehicle by two times. The sensitivity coefficient of the battery is largest in the FCEV, while that of the motor is largest in the series or series/parallel HEVs.

Acidified 2,4-dinitrophenylhydrazine (DNPH) solution, or DNPH-impregnated cartridges are commonly used for the collection of automotive exhaust carbonyl compounds. There are some DNPH-carbonyl compounds in not in use DNPH cartridges and DNPH solution. Furthermore, concentrations of automotive exhaust carbonyl compounds are decreasing according to improvement of the purification technology for automotive exhaust. Automotive exhaust carbonyl compounds become to be difficult to be analyzed with DNPH collection method, because of these two reasons. It is thought that reliable analysis of acrolein in automotive exhaust is very difficult because concentration of DNPH-acrolein in extracted solution is not stable. Furthermore, it is found out that DNPH-acrolein in DNPH-cartridge is disappeared for short time storage in this research.

Diesel Particulate Filter (DPF) is a very effective aftertreatment device to limit particulate emissions from diesel engines. As the amount of soot collected in the DPF increases, the pressure loss increases. Therefore, DPF regeneration needs to be performed. Injected fuel into the exhaust line upstream of the Diesel Oxidation Catalyst (DOC), hydrocarbons are oxidized on the DOC, which increases the exhaust gas temperature at the DPF inlet. It is also necessary that the injected fuel is completely vaporized before entering the DOC, and uniformly mixed with the exhaust gases in order to make the DOC work efficiency. However, ensuring complete evaporation and an optimum mixture distribution in the exhaust line are challenging. Therefore, it is important that the fuel spray feature is grasped to perform DPF regeneration effectively. The purpose of this study is the constructing a simulation model.

Seat belts for rear passengers are not commonly used, even though they can significantly reduce fatalities. A passenger seat belt reminder (PSBR) is installed in order to encourage seat belt use, but the effectiveness of PSBRs on the rear seat passenger has not yet been proven. We have developed a methodology to assess PSBR effectiveness. There are two pathways to encourage seat belt use. The first is that PSBR directly facilitates the passenger's use. The second is to motivate the driver request passengers to use seat belts. In the experiment, we asked participants sitting in the driver's seat to select one of five ranks of likelihood to encourage the passenger when a PSBR was presented. We also asked participants sitting in the rear passenger seat to select the rank of likelihood to use the belt voluntarily with PSBR and that to use the belt when the driver requested. The degree of likelihood was quantified by averaging the assigned percentage values to the ranks.

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.

The hydrogen consumption of fuel cell vehicles (FCV) can be measured by the gravimetric, pressure and flow methods within a ±1% error. These are the methods acknowledged by ISO and SAE [1, 2], but require the test vehicles to be modified in order to supply hydrogen from an external, rather than the onboard tank. Consequently, technical assistance of the vehicle manufacturer is necessary for this modification, while various components in the test vehicle must be readjusted. For these reasons, a measurement method free of vehicle modification is in great demand. The present study therefore developed an “oxygen balance method” which determines the amount of hydrogen that has reacted with oxygen in the fuel cell stack by measuring the oxygen concentration in exhaust gas.

In order to develop large-scale (100 mm in diameter) Mg-Zn-Y alloys with high strength beyond that of 4032-T6 alloy, we considered a novel casting process to produce large ingots with homogeneous microstructure, and investigated the mechanical properties of the extruded alloys. First, ingots (335 mm in diameter and 850 mm in height) were produced by a novel stir casting process in the ingot case. Then large-scale extruded alloys (100 mm in diameter) were prepared with an extrusion ratio of 10. The Mg-Zn-Y alloys exhibited higher yield and fatigue strengths than those of 4032-T6 aluminum alloy. The yield strengths of the aluminum alloy decreased drastically above 473 K, whereas those of the Mg-Zn-Y alloys did not. It is noteworthy that the yield strength (274 MPa) and fatigue strength (100 MPa) of the Mg-Zn-Y alloys at 473 K were about 1.3 and 1.2 times respectively as high as those of aluminum alloys.

Hydrogen concentration during combustion in a confined space with a ceiling was investigated. The results indicated that steady-state hydrogen concentration was highest at the ceiling surface for all hydrogen flow rates. When hydrogen concentration was 10-20%, weak flame propagation occurred at the ceiling surface, with the most easily burnable spots being dented areas such as seams, pores and creases on the ceiling surface. The unstable and limited nature of flame propagation at the ceiling surface was attributed to the relationship between temperature and hydrogen concentration in a confined space.

A premixed charge compression ignition methanol engine targeting a drastic decrease in NOx emissions and a brake specific energy consumption equivalent to that of a DI diesel engine has been developed (1). The problems of this combustion system are that the brake thermal efficiency decreases, and CO and THC emissions increase due to a deterioration of high load combustion. The purpose of this study is to improve the high load combustion of a premixed charge compression ignition methanol engine using a flash boiling fuel injection technique. The results of this study have shown that the premixed charge compression ignition methanol combustion system using a flash boiling fuel injection technique increases the brake thermal efficiency, decreases CO and THC emissions, while maintaining low NOx emissions in the high load region.

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.