A thick hydrogen-free diamond-like carbon (DLC) coated piston ring was developed for stainless steel sprayed bores. By applying the filtered vacuum arc method, the thick DLC and low hardness were achieved with less droplets, which solves both the adhesive wear by eliminating the chromium nitride coating and the abrasive wear by improving the DLC deformation ability.

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The deep learning model (DNN, Deep Neural Net) we proposed separates knocking sound from engine radiation noise measured by a microphone. In this paper, we propose a method for training a DNN which can be used in a wide range of rotational speed conditions. The proposed method applies data augmentation to measurement data under several conditions. In addition, the proposed method trains a DNN (UNet) for sound source separation using the results of the previous method. The proposed method can reduce the time required for training data collection. In terms of practical application, reducing the burden of data collection is an important improvement.

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In the research carried out for this paper, an injection strategy for predictably PCCI combustion with Alternative fuel of GTL, a series of experiments using a single-cylinder diesel engine and a spray observation vessel. The Injection system was revised by several injection timing, rate of injection quantities, and second injection ratio to optimize for spray-tospray collision and spatial and temporal distribution of the mixture. The results show that switching injection pattern improve IMEP, and the spray-to-spray collide two-stage injection, reduces NO without increasing CO and THC emissions.

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The objective of this study is to reveal the change of internal force state in element for metal V belt type CVT under driving conditions, where the transmitting torque is changed. Changes of the internal force in width direction accompanying with the change of the moving location was measured by attaching small size strain gages on an element. The force in the element was remarkably fluctuated in the pulley groove. The representative point of the resultant force was moved toward the exit of pulley groove when the transmission torque was increased. Test result showing the difference in internal forces at the left position and that at the right position was also explained by the precessional motion of the movable sheave where the contacting point between belt and pulley was shifted in the radial direction under high toque condition.

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Considering to promote EV bus mass operation in Japan near future, we have clarified necessary EV bus specification, electric power, electric energy, fuel cost for EV bus mass operation, which estimated by current bus service information operated by bus service office in Yokohama city, estimated by unique simulation method including actual results of EV bus verification test in Yokohama-city on FY2020,

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In this report, we investigated the effect of the friction torque of the differential gear on the transient characteristics of the vehicle and examined the control method of the differential gear to improve the transient characteristics of the vehicle. It was found that the transient characteristics of the vehicle are improved by reducing the friction of the differential gear to zero during steering and by applying the friction of the differential gear after the steering is completed. In a differential gear in which friction is generated in proportion to the drive torque, it is possible to control the friction of the differential gear by controlling the drive torque.

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Vaporization enhancement of a urea water solution for uniform atomization is required to improve the NOx purification efficiency for the urea SCR system. In this study, the atomization effect of the dimple depth and hole diameter were evaluated from critical Weber number, atomized droplets size after impingement, and visualization results at high time resolution. The visualization of droplet behavior using high-speed camera and image analysis confirmed that dimple with shallow and large hole diameters are effective in atomizing impingement droplets.

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A previous study reported that in a cylinder with a barrel-shaped bore deformation, the piston ring leaves the sliding surface of the bore in the high rotation range. In this paper, the jumping behavior of the rings is discussed in detail, and an estimation formula for the conformability of piston rings to follow the sliding direction is proposed. In addition, the dynamic behaviors of a ring for some simple bore deformations are analyzed using the program for ring-bore dynamic contact analysis developed in the previous paper. By comparing the proposed formula with the analysis results, the validity of the proposed formula is discussed.

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In comparison with port fuel injection (PFI) engines, gasoline direct injection (GDI) engines have higher fuel efficiency. However, there are more particulate matters (PMs) including soot in the exhaust gas. Then, we need gasoline particulate filters (GPFs) with high filtration efficiency for the future stringent PM emission regulations. In this study, we simulated the filtration process on the pore-scale of the filter wall by a lattice Boltzmann method (LBM). The structure of filter wall was obtained by an X-ray CT technique. We discussed pressure drop and initial filtration efficiency, which are important characteristics of GPFs, by changing the inlet velocity of exhaust gas and soot particle size. Results show that, as the soot particle size is smaller, the thicker soot cake layer is formed on the surface of the filter wall, resulting in the smaller pressure drop. The initial filtration efficiency is higher as the particle size is smaller due to the Brownian diffusion. Moreover, when the particle size is larger, the interceptional effect is dominant, and the initial filtration efficiency is higher. As the inlet velocity is smaller, the thicker soot cake is formed on the surface of the filter wall due to the higher filtration efficiency. The pressure drop decreases as the inlet velocity is smaller.

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The tooth profile circular used in the reduction gear ″single-tooth pinion gear″ that achieves high efficiency and high speed reduction has a problem in strength because the teeth thickness of the helical gear is smaller than that of the pinion gear. In the electric component motor, the helical gear is made of resin, and it is essential to improve the strength for practical use in the future. In this paper, it was confirmed that the strength can be improved while maintaining high efficiency by changing the tooth profile of the single-tooth pinion gear.

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In case of H. D. Trucks, HEV/PHEV are not to be conformed to CN2050 in CO₂. BEV is expected to meet the goal of CN2050 in CO₂ using the electricity under Japan Basic Energy Plan 2021. However, BEV is impossible to use for long range inter-city logistics because of great costs and weight of batteries how advanced in the future. Although CO₂ level and fuel cost of FCEV are now extremely high, but in the future FCEV’s CO₂ and fuel cost levels are going down to near BEV level. However, FCEV is expected to be difficult for a long range driving over 500km without filing on the way because it needs larger hydrogen tanks. Finally, H.D Trucks of EV with Dynamic power transfer and FC-RE-EV have a greater chance to be more effective with expanding energy supply-infrastructures for long range logistics.

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On-board PV system was evaluated by simulation model of energy balance between the estimated PV generation by solar irradiation and vehicle energy consumption. Influence of vehicle usage pattern and weather condition on vehicle irradiation was defined by vehicle road tests and a simulation model. On-board PV has a potential to reduce vehicle energy consumption, well-to-wheel CO2 emission, and number of plug-in charging.

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Herein, we conducted IEC 62660-1 cycle, high-temperature cycle, and high-temperature storage tests on sulfide-based all-solid-state batteries to evaluate their durability and degradation mechanism. On the basis of the high-temperature cycle test and cell analysis, the increase in the resistance of the batteries was attributed to the oxidation of the sulfide electrolyte at the positive electrode. Moreover, the decrease in the capacity caused by the consumption of active Li+ was attributed to the reduction of the sulfide electrolyte at the negative electrode. We also considered that the degradation mechanisms follow the Arrhenius law on the basis of the high-temperature storage tests.

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Automobile bumper beam which is one of the most important safety parts during front crash accident, is mainly subjected to a bending load and plays a key role in absorbing energy in collisions and protecting occupants. In this study, firstly a benchmark study about the material, manufacturing method and key external dimensions of bumper beam was performed. It is found that it has mainly the following kinds of structures: steel or aluminum press forming, steel roll forming and aluminum extrusion. And then steel roll-formed and aluminum extruded bumper beams which have a characteristic of constant cross section along the longitudinal direction were chosen, and a comparative study of crash performance and lightweight effect was conducted via numerical simulation. In which, the lightest aluminum extruded bumper beams according to required performance were obtained by using optimization design technology and the design guidance for thickness values of bumper beam walls became clear. The applicable areas of steel roll-formed part and aluminum extrusion were clarified by comparing the structural results of five types of external dimensions.

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While AI has been applied to object detection in the fields of ADAS and AD, a lot of research of Explainable AI, which is used to explain evidences of object detection results, has been conducted. Explainable AI has been mainly developed for 2D object detection and it has been rarely applied for 3D object detection. Therefore, we adapted the existing method of Explainable AI for 2d object detection to 3D one using point cloud and we report its result.

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The purpose of this study is to propose the digital human model system consisting of a rigid link model system, that reproduces the viewing posture considering eye-head coordination, and visibility evaluation system. The proposed human model reproduced the rational body movement necessary to gaze the visual target. It calculated the burden on the body and the eye. The angles of the head and eyeball in the model and the verification experiment showed a similar tendency. It was concluded that eye-head coordination was reproduced by the proposed model.

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The present study investigated the material properties of 1180MPa class recycled steel fabricated from waste scraps to evaluate the required performance of parts as steel sheets for automobiles. The recycled steel showed a strength-ductility performance comparable or better than that of 980 MPa class steel.: tensile strength of 1234 MPa, total elongation of 18%, stretch-flangeabilty λ of 21%, limiting dome height of 12.2 mm, and limiting drawing ratio of 2.09%. In the fatigue test with a stress ratio R = -1, the mirror finish material had a fatigue limit of 600 MPa at 107cycles to failure for both bending load and axial load. The fatigue limit corresponds to half tensile strength that is believed to be the maximum fatigue limit in cases of surface initiation of fatigue. Actually, all fatigue fractures originated from the specimen surface, and no internal initiation from inclusions were observed. The fatigue limits obtained by changing the stress ratio under bending load well matched the corrected goodman line. Therefore, the effect of average stress can be reliably evaluated from the fatigue limit diagram. In this way, the 1180MPa class recycled steel sheet has high fatigue strength with sufficient reliability and satisfactory meets the required performance of parts as a steel sheet for automobiles

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CAE has been employed to predict car body deformation due to water pressure and heat in the painting process. However, it is necessary to measure the deformation during painting process to verify the accuracy of the simulation. Thus, we designed a water- and heat-resistant displacement meter and measured the displacement on car body outer panels in ED paint tank and oven. And, the measured results are used to verify the thermal deformation CAE results.

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