National Traffic Safety and Environment Laboratory

To mitigate the "black-and-white tunnel" phenomenon and associated traffic safety hazards at highway tunnel entrances, this study proposes an intelligent control system integrating PLC and anti-halo technology. The research begins with illumination data collection and analysis at tunnel entrances, confirming the existence of the "black-and-white tunnel" effect. Specifically, daytime tunnel entrances exhibit a sharp increase in illumination (black hole effect), while nighttime entrances show a dramatic decrease (white hole effect). Both conditions significantly impair driver visibility and pose substantial safety risks. The implementation of the PLC and anti-halo intelligent control system effectively mitigates these illumination variations during both day and night, thereby reducing visual strain on drivers. This validation demonstrates the effectiveness of the proposed solution, which holds significant practical implications for road safety.

<div class="section abstract"><div class="htmlview paragraph">With advancements in the development of the automated driving technology, vehicles equipped with such technology can be observed widely in market. However, there is a lack of clarity regarding fuel consumption and emission characteristics with automated driving functions. In fact, it cannot be found that any technical papers that have conducted such an evaluation.</div><div class="htmlview paragraph">Therefore, in this study, it was investigated that an evaluation method to understand fuel consumption and emission characteristics by using the adaptive cruise control (ACC) function. The function is one of the automated driving functions which is widely used and corresponds to Level 2 defined by SAE International (Society of Automotive Engineers). In the approach taken for this study, two vehicles were used as the real driving emission test and the preceding vehicle—equipped with a driving robot—was driven accurately to trace the speed pattern defined by the test cycle. The trailing vehicle was driven using the ACC function, and various performance information of the vehicle was acquired. As the result, it was found that various vehicle performance information with the ACC function was evaluated accurately and the usefulness of the method taken for this study was confirmed experimentally.</div></div>

Regional railways, where equipment is aging, frequently experience derailment accidents due to gauge widening. This paper shows a detection method of gauge widening by measuring the positional relationship between the rails and the wheels. The proposed method uses a small, simple camera, which is easy to install and allows inexpensive measurements. The points where the gauge is widened, are identified by section images of rail and wheel extracted from moving image shot by the camera. An overview of the measurement device and experimental results of a commercial train are reported.

The trolley contactors installed on trolley wires are used to detect streetcars' positions and control their routes. The passage of a streetcar is detected when the pantograph contacts the mechanical switch of the trolley contactor. This requires periodic maintenances in high places, which are heavy burdens. Global Navigation Satellite System (GNSS) has been considered as an alternative to the trolley contactors. The accuracy of GNSS varies greatly depending on the surrounding environment. It is necessary to evaluate the accuracy of streetcar position detection using GNSS in advance. We propose the evaluation technique for the accuracy of streetcar position detection using GNSS.

Initiation methods for thermal propagation tests are being discussed in the EVS-GTR. In this paper, laser irradiation was compared with nail penetration and heater heating using a prismatic Li-ion battery module from the viewpoint of heat energy transfer to adjacent cells. Such transfer with laser irradiation was 0.025% of that of heater heating and the adjacent cell’s temperature rise was less than 1°C by thermal runaway of the target cell. This result demonstrates that laser irradiation is a rational method in terms of replicating single cell thermal runaway only due to the cell’s own energy.

可変バルブを用いて燃焼制御する場合，解析したいサイクルの他に他サイクルの影響を受ける．そのために，従来の数値解析では実機で得た吸気温度や吸気圧力等のデータを使用し筒内状態を再現していた．そのため，残留ガス等の影響を考慮できず数値解析の精度の確保が難しかった．そこで本研究では，1Dおよび3Dシミュレーションを連携することで，より高精度かつ軽計算負荷で予測する方法を提案し，その妥当性を検証した．

The advantages of plastic gears are light weight and can be used without any lubricant, and the disadvantages are that its low strength and large environmental impact. Therefore, the development of a new gear that maintains the advantages while negating the disadvantages has been proposed. The development of sustainable and reproducible natural materials is particularly desired to address environmental problems. In this study, a method was devised to extract high quality and highly precise bamboo fibers using a machining center. Then, the hot press method was used to produce a Bebel bamboo gear, which is a machine element with a complicated shape. The present paper describes the characteristics of the bamboo fiber gears investigated through experiments. In this study, we investigated the effects of changing the cutting and molding conditions for fiber extraction on the black color parameter and strength.

Surface-enhanced Raman scattering (SERS) and magnetic resonance imaging (MRI)-guided phototherapy are new breakthroughs in cancer therapeutics due to their complementary advantages, such as enhanced imaging spatial resolution and depth. Herein, we synthesized monodispersed Prussian blue-encapsulated gold nanoparticles (Au@PB NPs), in which the plasmonic gold core plus coordination polymer of cyanide (C[triple bond, length as m-dash]N) and iron ions coincidently become a superexcellent contrast agent for both MRI and zero-background SERS imaging. PB, as a signal source for MR and SERS, can be easily assembled onto single Au NPs, of which iron ions possess high relaxation efficiency for in vivo MRI, e.g., the longitudinal and transversal relaxation efficiency values are 0.86 mM-1 s-1 (r1) and 5.42 mM-1 s-1 (r2), respectively. Furthermore, with the help of the plasmonic enhancement of the gold core, the C[triple bond, length as m-dash]N groups exhibit a specific, strong, and stable (3S) SERS emission in the Raman-silent region (1800-2800 cm-1), allowing accurate in vivo imaging at the single or even subcellular level. More importantly, PB has remarkable absorption properties in the near infrared region, and can be used as a photosensitizer for photothermal (PT) and photodynamic (PD) therapy simultaneously. Hence, the ideal integration of a plasmonic Au core and PB shell into a single monodispersed MR-guided NP, with zero-background SERS signals, is an important candidate for both tumor navigation and in situ PT/PD treatment guided by SERS/MR dual-mode imaging.

In this study, two kinds of control methods for the transient operation of an engine test bench for heavy-duty vehicles were applied in the JE05 test cycle and World Harmonized Transient Cycle (WHTC) test conditions in order to evaluate the controllability of transient operations and the effect on emissions. One control method uses dynamometer torque with its inertia correction as the feedback signal (dyno torque F/B control); the other method uses axial torque measured by a flange-type high-response torque meter as the feedback signal (axial torque F/B control). The transient operation controllability using the axial torque F/B control improved compared with the dyno torque F/B control. The results influence NOx emissions in the emissions test cycle, such as JE05 and WHTC, with the engine test bench. Axial torque F/B control could become a more useful technique when it is required to improve the reproducibility of real driving conditions.

<div class="section abstract"><div class="htmlview paragraph">NOx emissions from diesel passenger vehicles affect the atmospheric environment. It is difficult to evaluate the NOx emissions influenced by environmental conditions such as humidity and temperature, traffic conditions, driving patterns, etc. In the authors’ previous study, real-driving experiments were performed on city and highway routes using a diesel passenger car with only an exhaust gas recirculation system. A statistical prediction model of NOx emissions was considered for simple estimations in the real world using instantaneous vehicle data measured by the portable emissions measurement system and global positioning system. The prediction model consisted of explanatory variables, such as velocity, acceleration, road gradient, and position of transmission gear. Using the explanatory variables, NOx emissions on the city and highway routes was well predicted using a diesel vehicle without NOx reduction devices. However, the prediction model had some limitations owing to the effects of NOx reduction devices. In this study, among various NOx reduction systems, a diesel vehicle with NOx storage catalyst (NSC) was chosen to predict the NOx emissions under a catalytic system. To improve the accuracy of the NOx emissions under the NSC, a catalyst model was added to the prediction model and used to predict the catalyst properties. By adding the catalyst model, the accuracy of NOx emissions of the prediction model was improved compared to the previous prediction model with individual explanatory variables. The NOx emissions were well predicted compared to the measured data.</div></div>