A correlation has been confirmed between the mass burnt fraction 50% crank angle (MBF50%CA) and b₄/IMEP, which is obtained by dividing the amplitude b₄ of the 4th-order sine component in the cylinder pressure by IMEP. Using this method, MBF50%CA was estimated from b₄/IMEP. As a result, the estimated value was close to that calculated from conventional thermal calculations. The method in this paper has advantages such as low impact on accuracy when the number of sampling data per cycle is reduced, and no need for absolute pressure calibration. This method is expected to be used in actual vehicle measurement.

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A cylinder block involves bore deformation due to assembling stress of cylinder head and thermal stress. Friction analysis method of a piston skirt was established and the bore deformation effect on engine performance was clarified. Bore distortion analysis revealed the bore profile of constriction at bottom side and expansion toward upper side in the case of normal bore. This distortion is found to be the cause of exacerbation of the trade-off between skirt friction and piston slap. As a result of CAE prediction, ideal cylindrical bore under the highest thermal load condition significantly improved skirt friction, blow-by gas flow and LOC. Simulation results indicated that the change of design parameters for piston and rings lead to additional improvement of engine performance.

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We propose methods which train deep learning models (DNN, Deep Neural Net) to separate knocking sounds from engine radiation noise measured by a microphone. These DNNs contribute to the automation of ignition timing calibration for the gasoline engine by evaluating the intensity of knocking. The previous method has two problems. First, separation performance deteriorated for engines not included in the training data. Second, this method required in-cylinder pressure for training. In this paper, we propose a method that can separate the knocking sounds of engines not included in training data and an unsupervised method that does not require in-cylinder pressure.

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As a new tool to explore potential wall-structuring strategies for cooling loss reduction on diesel engine combustion chamber wall, a technique for high-speed thermography of riblet-structured wall surface impinged by a diesel spray flame was developed. The riblet structure was machined on a surface of a quartz window plate with ultra-sonic spindle, roughened with sand blasting and coated with 0.6m-thick chromium and 30nmthick SiO protection layers. The quartz plate was attached onto the inner surface of a pressure-proof quartz window for a constant-volume combustion chamber. The riblet-structured surface was impinged and heated by a single-shot diesel spray flame and the infrared radiation from the chromium coating was successfully visualized with high-speed infrared camera at 128 x 128 pixels resolution and 10kHz frame rate, enabling investigation on the effects of riblet structure on the previously reported radially striped temperature distribution and its advection velocity.

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A cylinder block with cylindrical bore considering deformation by assembling cylinder head and thermal stress under the highest thermal load condition is expected improving engine performances as analyzed by CAE. Test results verified that the friction force, noise level, blow-by gas flow rate, and lubricating oil consumption were reduced by cylindrical bore. Besides improved high-load performance, this cylinder block enhanced engine performance under low-load conditions with low thermal stress. Cylindrical bore has impact for reduction by 2.7% with zero pin-offset piston and improvement other performances for normal bore.

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Wireless dynamic charging requires heavy-duty and light-duty vehicles to share transmission coils embedded in the road. In this research, a method of arranging multiple transmission coils in an array and exciting each coil in phase to reduce the magnetic flux interference between adjacent coils has been proposed. This method enables the supply of optimum power irrespective of the vehicle size.

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In the vehicle development, it is necessary to repeat function designs and layout designs to meet many constraints such as function requirements. For the reduction of repetitions, it is required to find a feasible set where all constraint functions are satisfied in the early stage of vehicle development. In this paper, we propose a novel method to solve a feasible region exploring method called Differential Evolution Based Adaptive Sampling (DEBAS). Moreover, we present an application of DEBAS to a double wishbone suspension design problem which has a lot of constraints functions and design variables.

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The topology optimization helps realize highly rigid yet lightweight multi-material vehicle bodies for lower CO2 emissions. We developed a topology optimization method aimed at minimization of the mass of multiple materials, with stiffness, dynamic large deformation, and vibration performance requirements as constraints. Applying this method to an L-shaped member with steel and aluminum materials, we achieved an optimal structure and all the objective functions converged to the desired level. Consequently, an optimal shape was obtained that places each material in the right place, simultaneously satisfies stiffness, dynamic large deformation, and vibration performance requirements, and minimizes the mass.

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1180MPa ultra-high strength steel is predicted to be applied to energy absorbing (EA) parts for automotive weight reduction. The purpose of this study was to investigate the applicability of 1180 MPa steel to actual EA components. Actual front-side-members applied with 1180 MPa steel were evaluated for their effects on weight and EA performance by FEM analysis and experiments. The experimental results of the developed structure showed 11% decrease in weight and 10% increase in EA from the base structure applied with 590 and 780 MPa steels. It was important to apply the spot weld fracture prediction model to improve the accuracy of FEM analysis.

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A simple method was developed to predict tire vibration characteristics from big data on the blocked force of actual tires for use in the early stages of road noise development. By using eigenmodes and strain energy, the contribution of the tire and suspension to the internal forces in the hub bearing was analyzed and three tire-dominant vertical resonances were extracted. For these resonances, the tire blocked force obtained simply under free support conditions was able to discriminate differences in vibration characteristics between tire types during driving. The big data of the tire resonance frequency efficiently obtained by this simple measurement method and the dimensional index value calculated from the tire size showed a tendency to be inversely proportional. It was found that the range of tire resonance frequencies could be easily predicted from the tire size parameters and simple measured tire big data.

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With electrification of vehicles, compactness/lightness and quietness of HVAC is required, to improve electricity consumption and cabin comfortability. In this study, applying sound-absorbing structures using perforated panels target to HVAC to reduce noise without changing its overall size. The challenge in applying sound-absorbing structures to HVAC was considered to be the change in sound absorption characteristics depending on the sound incident angle. To meet this issue, we introduced partitions in the air cavity behind the perforated panel. The design method of the partitions was studied experimentally, and the evaluation in an actual HVAC unit confirmed that a sound-absorbing structure using perforated panels could reduce noise at the targeted frequency.

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The new 2-motor hybrid powerplant prototype equipped with an electric motor and a newly adopted gasoline directinjection engine was faced with a high torque fluctuation problem due to the high compression ratio of the engine, the advanced intake-valve-timing angle of hydraulic lash-adjuster, and the large operating-angle of the torsional-damper located between the motor and the engine. In the research work, the operating angle of the electric valve-timing control was increased and the pre-damper characteristics was optimized, so that the internal torque fluctuation and resultant body vibration during engine start-up were successfully reduced to the same level as the previous model.

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In this study, technology for predicting engine vibrations during startup in vehicles equipped with a V6 engine has been developed. A model was formulated for the hydraulic mounts located at the front and rear of the engine, which takes into account not only frequency dependence but also amplitude dependence. The roll vibration input from the engine to the body, occurring during engine startup, was clarified using this model. As a result of this research, improvements to the characteristics of the hydraulic mounts can now be made more easily, while taking ride comfort performance into consideration.

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This paper describes a method for automatic calculation of infrastructure sensor placement to reduce design effort for an Autonomous Driving System (ADS) that cooperates with infrastructure sensors installed in the Operational Design Domain (ODD). This method estimates the blind spot area as seen from ADS based on the ODD conditions and a 3D point cloud map of the ODD design area, and automatically calculates the infrastructure sensor placement that minimizes the estimated blind spot area. The results of the evaluation confirmed that the results were equivalent to those obtained when the sensor placement was examined manually.

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Spring-mass systems are commonly used in the design of vehicles considering crash worthiness for occupant protection. On the other hand, if the crash is considered as the absorption of the vehicle’s kinetic energy in the crushable zone, it can be regarded as a damper-mass system. In this paper, an impact model using damper-mass system is compared with a spring-mass system, assuming a situation where the front frame of the vehicle is crushed by the impact. As a result, it can be said that it is reasonable to use the damper mass system as an impact model.

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This paper deals with a lane-keeping control under a tire blowout. A lane keeping assistance system in a tire burst has a risk of conflict between the steering action of the driver and that of the assistance system. To reduce the conflict, the assistance system proposed by our previous research was improved to reduce the conflict by introducing on algorithm to shut off a driving assistance torque when a conflict occurred. The experiments were carried out to confirm an effectiveness of the improved assistance system. The experimental results showed that a lateral deviation of the vehicle and a driver’s unnecessary steering maneuver were able to be reduced by the improved assistance system. Then, it was confirmed that the risk of a lane departure under the tire blowout and the conflict between driver and driving assistance torque was able to be reduced by the improved assistance system.

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Effective computational procedures to treat ductile fracture problem in Isogeometric analysis (IGA) are proposed. In this study, a technique for reproduce crack propagation with trimming curves by adding control points in IGA is described. The reproducibility of stress concentration, various crack propagations, and computational efficiency of the proposed method are verified using tensile example calculations.

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Autonomous driving is expected to solve various other social issues, as well as increase the international competitiveness of the automobile industry. It is difficult for autonomous driving to deal with unexpected situations. Therefore, remote driving is expected to serve as a backup in such situations. In a remote-controlled vehicle system, a pilot is affected by lack of physical sensation and communication delays of camera images. It is necessary to evaluate the driving characteristics and driving load of a remote vehicle pilot. This study aims to clarify the effects of communication delays of camera images in the speed ranges of 20 km/h and 50 km/h on the driving characteristics and driving load of the remote pilot based on physiological signals using driving simulator.

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The ambient conditions in the emission measurement test procedure for light duty vehicles are defined as an almost constant temperature (23 deg C) and humidity (50%RH). However, in the real driving situation, the temperature and humidity are widely dispersed. Therefore, several couples of temperature and humidity conditions were adopted for the emission measurements and the correction methods were considered in the previous study. In this study, the considered methods were applied to the emission results of a driving test. As the result, the correction factor for the exhaust emission during the driving test was calculated as around 1.05. It has corrected the basic nature of exhaust emissions from engines. Thus, it is necessary to correct the effects caused by the engine control related to the surrounding temperature and humidity, as a next task.

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In this study, we developed a new coating by applying radical nitriding treatment to TRD-treated VC coating, and succeeded in improving the endurance of dies in the press working of ultra-high strength steel. The radical nitriding treatment on the TRD-VC coating extended the die life more than five times, and improved the endurance of the die. A metallic nitride layer is formed on the extreme surface (30 nm) of the TD-VC+RN coating. Cr and Fe diffuse in pole surface layer of the coating. The improvement in die endurance is attributed to the following two facts: (1) the nitride layer on the pole surface lowers the coefficient of kinetic friction and reduces adhesion, and (2) impurities inside the coating diffuse to the surface, improving toughness.

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We have shown that the shape of parking vehicles and scenes can be estimated with high accuracy using a high-resolution millimeter-wave radar for automated parking and parking assistance in our previous studies. In this paper, we propose a method for estimating the shape of parking vehicles from only range and Doppler information, using a low-cost millimeter-wave radar without multiple antennas by applying deep learning techniques. It is shown that it can be estimated with high accuracy in real-world parking scenes.

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As an automotive computing platform for solving combinatorial optimization problems in real-time, novel automotive computer architecture which has Quantum inspired Processing Unit (QiPU) is proposed. A prototype of Simulated Bifurcation Machine (SBM; one of Quantum inspired machines), which can execute Multiple Object Tracking (MOT) in real-time by collaborating with AI calculation, was implemented in an automotive mass production FPGA and verified. As a result, the compatibility for autonomous driving system and the effectiveness in the MOT application is proven by evaluation.

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Based on a cellular automaton model of traffic flow, the mixed traffic flow dynamics with both conventional vehicles and connected autonomous vehicles (CAVs) was studied in terms of both the CAV-penetration rate and a connection range. CAVs behave synchronously with other CAVs ahead via real-time communication. The flux never reaches steady state above the critical density even though the traffic flow model is deterministic. With the CAV-penetration rate increases, the trade-off of an increase in flux and a destabilization of traffic flow becomes prominent. The connection range expansion increases the flux only when the CAV-penetration rate exceeds a certain threshold.

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Toward the realization of carbon neutrality, it is expected to improve engine thermal efficiency by combining combustion and fuel, as well as reduce WTW CO₂ by reducing the carbon intensity of fuel. In this study, the evaluation of the effect of fuel molecules on thermal efficiency and exhaust emissions using a highly efficient super lean burn engine of λ2 or higher is conducted, and the characteristics required for fuel is clarified.

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Potential of a dual-fuel engine of hydrogen ignited using diesel pilot was explored at a high load of 1.2MPa in IMEP by 3D-CFD. The CFD results have shown that ignition timing of hydrogen can be well controlled by optimizing the injection timing and quantity of diesel pilot, and mild burn with low NOx can be obtained by large amount of EGR gas. In the case of the homogenous distribution of hydrogen, that was conducted by early injection of hydrogen, the indicated thermal efficiency can reach 48.5%, that is the same level with a diesel engine. At the same time, engineout NOx can be drastically reduced to 50ppm (1/4 level of diesel) even at high load of 1.2MPa (IMEP) with a high ratio of EGR gas. Furthermore, hydrogen diffusive combustion conducted by the late injection (around TDC) of hydrogen with diesel pilot was explored by 3D-CFD. It has been indicated that thermal efficiency of the diffusive combustion, that is free from preignition, can be pushed to around 55% by increasing compression ratio.

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In order to improve thermal efficiency while keeping extremely low NOx emissions of spark ignition engines, a new combustion technique which combined pre-chamber combustion with fuel reforming has been proposed and verificated by engine bench tests. In this report, for the purposes of investigating for the effects of pre-chamber specifications on combustion in pre-chamber and main chamber, specifications of prechamber nozzles were varied and the engine performance was evaluated on a single cylinder pre-chamber gasoline engine. As results, effects of pre-chamber specifications were clarified, combustion characteristics in pre-chamber and main chamber were improved, and stable operable regions was extended up to lambda 3.0. Comparing to the normal SI combustion mode, thermal efficiency was improved up to 17%, NOx emission was reduced to under 0.1g/kWh.

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Improving the thermal efficiency of gasoline automobile engines is a very important issue as a measure against global warming. For that purpose, we need to optimize the gasoline fuel so that the high engine performance can be fully exhibited. In the present study, the ignition delay times of light olefins and oxygenated hydrocarbons (assuming biofuels), which can improve knock resistance and expand the lean limit, were measured using a high-pressure shock tube and these chemical effects were discussed. In addition, new gasoline surrogates containing these components appropriately were suggested and their fuel performances were also examined.

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AOI (Automobile and Oil Innovation) Project has started as a collaboration between industries and academia. It was shown that increasing the portion of olefin in gasoline can extend the lean/dilution burn limit. Thereby, in this study, the effect of fuel components on combustion characteristics, such as thermal efficiency, dilution limit, cooling loss, unburnt loss were examined using a single-cylinder engine to understand the complex factors in combining different kinds of fuels. EGR rate was changed at stoichiometric condition with varying compression ratio and tumble ratio. As a result, not only Octane number and laminar burning speed, but also Lewis number and Karlovitz number should be accounted for to understand the experimental results.

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We work on improving the technology for predicting the gas seal performance of head gasket. Among them, I would like to judge the difference in the engine evaluation results with different rubber materials. In order to consider deterioration during engine evaluation, we focused on the reduction of rubber thickness. We have developed a new unit evaluation method to quantitatively judge the reduction of rubber thickness. The evaluation conditions are based on analysis results that simulate engine evaluations. New prediction technology that combines these showed the same results as the engine evaluation.

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The unburned components that do not contribute to combustion emitted from internal combustion engines should be significantly reduced. In this study, enhancement of a post oxidation under cold conditions was investigated by controlling the in-cylinder gas properties of a directinjection gasoline engine equipped with a variable valve system. The combination of “Late Intake Valve Opening” and “Late Exhaust Valve Opening” functions was verified. The results showed that THC and PN were further improved due to the increased superheat, intake air flow enhancement, and re-burn effect of the exhaust process.

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Using a mathematical model considering the product of inertia of 5 degrees of freedom, a detailed analysis was carried out by the energy flow method. As a result, the torsional deformation of the rear frame destabilizes the weave mode, which is caused by the lateral force of the front and rear tires. Specifically, rear tire lateral force destabilizes the weave mode due to torsional direct deformation of the frame. On the other hand, in the case of front tire lateral force, the weave mode becomes unstable as a result the steering angle phase delay. Differences between the destabilization mechanisms obtained in the modified model and those in the so-called JAMA model are discussed.

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This paper investigates real-time optimal feedback control for an autonomous vehicle. The applicability of a deep learning neural network controller using the simplified model open-loop optimal control solution as supervised learning data is investigated for path following and obstacle avoidance maneuvers on the road, including straight and curved sections. The constructed controller can obtain optimal control variables for given states and constraints in real-time without iterative computation. The numerical results using the full vehicle model show that the proposed controller has the potential for real-time optimal obstacle avoidance control of the conventional type of vehicle.

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Nowadays, the convergence of vehicle motion at high speeds is performance-designed by means of controlling the phase of tire side force. The paper discusses the methodology for evaluating the convergence of 3DOF vehicle model motion. Then, the capabilities of country-specific damping enhancement methods are evaluated and compared alongside each other.

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Twist Beam Suspension has two trailing arms and torsion beam which is coupled to left and right of the trailing arm. The suspension kinematics is based on deformation of the torsion beam; hence the prediction of kinematics is a set of complex calculations. Therefore, the kinematic mechanism have been studied and a simple link model was constructed. The Toe and Camber angle which depends on the wheel stroke has been calculated using linear transformation with simple link model. The validity of the calculation method using simple link model has been confirmed by comparison with calculation and the measurement results.

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The lateral and vertical force of the contact point is important for vehicle stability. Twist beam suspension is an integrated structure in which the left and right are connected, hence the input force is distributed to both sides. Therefore, the mechanism of translation of the lateral force acting on a twist beam suspension into a vertical force has been investigated. Using a simple model, a relational equation was derived that translates the lateral force acting on the contact point into a vertical force. The validity of this mechanism has been confirmed by the comparison of calculation and measurement results.

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The purpose of this study is to examine the factors that affect the judgment of whether or not to resume driving in automobile driving support based on the test results of our hospital.90 stroke patients over the age of 70 were subjected to neuropsychological examinations and examinations using a driving simulator, and multiple logistic regression analysis was performed.As a result, two factors, the S–PA unrelated pair and the number of instantaneous visual correctness, were extracted.We will continue to analyze the items that determine whether stroke patients can drive or not.

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For automated driving systems and driver assistance systems, recognition performance of the outside world is critical to ensure safety. In this study, we evaluated the recognition performance of a stereo camera in a rainfall environment using an artificial rainfall system that can evaluate the recognition performance of a vehicle in driving conditions, and evaluated the recognition performance of a vehicle with a driver assistance system using only a stereo camera.

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We developed a numerical electrodeposition (ED) model and validated its accuracy by comparing experiments and simulations using various kinds of paints and pretreated steel plates. The model was implemented in a next-generation finite element code (ES-FEM), which achieves high accuracy even with 4-node tetrahedral meshes. Besides, it was demonstrated that the difference in paint and pretreatment properties can be simulated adequately in large-scale analysis using actual paint process and car body models.

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