For the PN reduction of the direct-injection gasoline engines, it is necessary to divide an injection during a combustion cycle into multiple times. To this end, injection control of small injection quantity is important.We clarified that a factor to disturb responsiveness was an eddy current in the injector magnetic circuit.We developed a newly magnetic circuit that has taper structure at inside of a stator core for the eddy current reduction.As a result, the valve closing deray was reduced up to 16%.

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Urea SCR system is effective post treatment device of diesel engine to remove NOx in exhaust gas. The purpose of this study is constructing simulation model capable of predicting spray behavior and NH₃ concentration distribution. In order to achieve the purpose, it is necessary to clarify urea solution spray behavior injected by Urea SCR injector and concentration distribution of NH₃ generated by chemical reaction in experimental analysis. In this report, spray behavior was grasped in detail by experimental analysis, and the model constantswere optimized based on the obtained information.

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Urea SCR system is effective post treatment device of diesel engine to remove NOx in exhaust gas. The purpose of this study is constructing simulation model capable of predicting spray behavior and NH₃ concentration distribution. In order to achieve the purpose, it is necessary to clarify urea solution spray behavior injected by Urea SCR injector and concentration distribution of NH₃ generated by chemical reaction in experimental analysis. In this report, NH₃ and HNCO concentration distribution were measured by FTIR, and urea concentration distribution was calculated.

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Soot formation characteristics of the three-component gasoline surrogate fuel, which is composed of iso‒octane, toluene and n‒heptane was experimentally studied using a standard shock tube. The experimental results show that soot yield decreases with increases in the rate of oxygen addition. The bell peak temperature at which the maximum soot yield is obtained tends to decrease with increase of the oxygen addition. With reference to soot formation characteristics of the single component, maximum soot yield is obtained around the bell-peak temperature of 1900K for iso-octane and nheptane, and of 1800K for toluene. Iso-octane and toluene have comparable soot yield around the bell-peak temperature.

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A simplified model for estimation of fuel adhesion amount by post-injection in the DPF regeneration mode was developed in order to predict the engine oil dilution. Spray development process before the impingement on the cylinder wall was modeled based on 1-D spray development model considering the breakup and evaporation processes of fuel droplets. Fuel adhesion amount was estimated by judging the impingement of fuel droplets using physical values such as droplet diameter and velocity in the spray model.

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The effects of engine speed, torque, and oil temperature on the fuel evaporation from diluted oil in diesel engines were measured to construct an empirical model to predict the fuel evaporation rate. The coupling of the evaporation model and the model developed in our previous report to predict post injection sprays provides the method to estimate the oil dilution rate during the engine operation with regeneration. The model validation were performed at three constant speed conditions and two transient cycles. The oil dilution rate predicted by the model has a good agreement with the experimental data measured by Gas Chromatography.

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Promotion mechanism of wear and formation of tribofilm on DLC by Molybdenum based lubricant additives has not been sufficiently revealed. Therefore, we conducted friction and wear test with DLC, FC250 and Molybdenum based lubricant additives and observing and analysing sliding surface of specimens. As a result, the promotion mechanism of wear for the DLC was different by type of Molybdenum additives and it was difficult to form deposits on surface of DLC by Molybdenum additives. Moreover, it was found that hydrogen content in DLC is not main factor of promotion mechanism of wear by Molybdenum based lubricant additives.

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The authors previously developed the on-board polytropic index prediction model for compression stroke, which is a part of models for Model Based Control. The present study compared between the cooling losses and polytropic indexes predicted from our developed model and those measured under four different driving conditions. It was confirmed that the averaged relative errors of cooling loss prediction, under the base condition and various load conditions, were evaluated to be 4.9% and 7.3%, respectively. Additionally, the averaged relative errors of polytropic index prediction under the base and various load conditions were evaluated to be 0.1% and 0.7%, respectively.

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The soot formation model (233 species and 1375 reactions) was improved for gasoline surrogate fuel (GSF) with toluene, n‒heptane and iso‒ octane mixtures. In this GSF model, the method of moment was used for particle calculation. We tried to adjust the reaction rate constant of nucleation reaction so as to accelerate the early stage of soot formation. In addition, the reaction rate constant of the acetylene addition reaction on the surface of soot particles was also changed in order to control the soot particle growth. The calculated soot yield and temporal profile of soot formation were agreed with the experimental data by shock tube for in pyrolysis and oxidation conditions (φ=5, 10) at 0.235 and 1.2 MPa.

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Premixed Charged Compression Ignition (PCCI) is focused because of high required for environment. However Combustion Noise (C.N.) and Smoke increase while switching conventional and PCCI combustion. The purpose of this study is compensation of C.N. and Smoke in several environment and driving condition. Prediction model of C.N. and smoke and injection spray model with considered cylinder space were built. We developed controller with combined these models, it could automatically calculate optimal injection pattern to compensate C.N. and Smoke.

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In this study, exhaust gas components emitted from spark ignition (SI) engine were analyzed by using a comprehensive two-dimensional gas chromatograph (GC×GC) with a time-of-flight mass spectrometer (TOFMS). N-hexane, 1-hexene, n-heptane, isooctane, cyclohexane, methylcyclohexane and toluene were used as fuels. As a result of the analysis, it was found that nitrogen-containing hydrocarbons are contained in exhaust gas. In addition, nitrated hydrocarbons were contained in detected compounds.

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One of main issues in rotation measurement of engine crankshaft is angular error. We evaluated the effect of the error using a prototype crank angle reference unit which can be mounted on the engine. In order to reduce the angular error, “Equal division averaging method” was applied. Application of the new measurement technique resulted in reduction of the maximum error to about 2.3[mdeg.]. The method with the prototype unit was then applied to a real engine. The correlation between rotation measurement and in-cylinder pressure is reported.

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When the sampling data number of 1 cycle is decreased, an indicated mean effective pressure calculation error from pressure diagram increases. This factor is effect of aliasing by the decrease of sampling data number. It is verified on steady operation conditions that error reduction can be performed by excluding this effect. In this paper, verification by transient operation was performed and good result was obtained like steady operation.

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It is well known that the spark-ignition engine combustion is extremely sensitive to the quality of gasoline fuels. In this work, a hypothetical kinetic mechanism for the anti-knock effect of the tetraethyllead (TEL) has been tested and analyzed by a numerical kinetic modeling. Scarce effect was found for the laminar flame propagation velocities by the TEL addition. On the other hand, generally large effects on the ignition delay times of fuel-air mixtures were demonstrated by TEL additions. More interestingly, the effects significantly depend on the type of the hydrocarbons in the fuel. The effects were interpreted by the assumed kinetic mechanism and the role of HO₂ radicals in the oxidation of hydrocarbons.

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Improvement of the activity of three-way catalysts (TWC) is extremely important to meet future emission regulations. In this study, the detailed catalytic behavior of Pd particles on ceria/zirconia was investigated by FT-IR. After severe engine bench aging at 1000°C, Pd particles were greater than 20nm and significant decrease of reaction rate constant for both CO oxidation and NO reduction were observed. Characterization results provided a causal relationship between deterioration of NO reduction and the disappearance of active linear-CO on the Pd surface. In addition, a CO oxidation reaction mechanism on the Pd surface is proposed. This work highlights how FT-IR can be used to understand Pd surface chemistry on the support materials.

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Direct injection spark ignition gasoline engines have shown increased particulate matter emissions in cold start conditions due to the pool combustion of the wall fuel films. Hence, further understanding of the in-cylinder pool combustion is required. In previous studies, we devised an experimental model that reproduces sooting characteristics of in-cylinder pool combustion as a steady phenomenon using an opposed-flow burner. In this study, we investigated the effect of butanol addition to iso-Octane/Toluene blends on sooting behavior. Experiments were conducted using four isomers of butanol as alcohol fuel and replacing a part of iso-Octane with them. As results, it was shown that the experimental values of PVF were the maximum at a slightly lean equivalence ratio of pre-mixture. The maximum PVF equivalence ratio did not change depending on the kind of blended alcohols. s-Butanol and n-Butanol had a large effect on soot reduction, and i-Butanol and t-Butanol did not show sufficient effect.

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The knock phenomena observed during premixed flame propagation in a constant vessel was investigated using the one dimensional density based combustion solver developed internally. As a result of calculation with the density gradient observed in the experiment, cool flame was formed from the flame side as with the experimental result, and hot flame occurred from the flame side, after that strong pressure oscillation was observed. These results show that the occurrence of temperature gradient causes strong knock.

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In the field of automotive transmission systems, there are multiple layers from final products to basic principles, and there is no structure that leads directly to seeds and needs. For this purpose, it is necessary to connect needs with basic research to find research themes, and to have an activity scheme to promote interests and goals and to promote collaborative research. This research proposes the introduction of an activity promotion framework for engaging in planning promotion in collaborative basic research, and the research theme excavation framework for searching for the theme of basic research common to each company.

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In recent years, reducing the number of cylinders of an engine has been advanced for fuel saving. However, as the cylinder number is reduced, the torque fluctuation from the engine increases and the NV performance deteriorates. Therefore, the importance of torsional vibration reduction technology has been rapidly increased, and active research and development is under way. Among them, CPVA is attracted to attention because it effects in the full revolution range. In the previous studies, the theoretical analyses focusing on the pendulum path for the purpose of improving the performance of CPVA were carried out and the influence of the path on the vibration damping performance of CPVA was clarified. In order to clarify the influence of the pendulum path, in the theoretical analysis, the pendulum path was an arbitrary path and was represented by a 6-order function. In this report, experiments are carried out for the purpose of verifying the theoretical analysis developed by us in the previous reports. In experiments, two different CPVA are developed and used. Comparing the theoretical calculation results and experimental results, the effectiveness of the theoretical analysis is clarified.

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In order to promote EV application in bus and truck categories, and to achieve low carbon, zero emission and good fuel economy of public transportation, we have developed low price EV system technology for bus/truck utilizing mass-production technologies of passenger EV. In this paper, we report major contents of this development and EV bus proving test to confirm this technology.

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Heavy-duty plug-in hybrid electric vehicles (PHEV) are anticipated an increase. PHEV can be operated by motor driving or hybrid driving which combine engine and motor. Fuel economy and emission of PHEV change by the different of those operate modes. In this study, fuel economy and emission of PHEV were evaluated by operating several plug-in hybrid controls. On this experiment, we used the EILS (Engine-In-the-Loop- Simulation), which was constructed by actual engine and HILS (Hardware-In-the-Loop- Simulation). The results of this experiment are obtained that the emission (NOx) at engine starting cycle in the CD (Charge Depleting) range was the worst. In order to improve NOx, the engine of PHEV is necessary to be operated aggressively at the driving point of high power in the CD range.

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One of the major obstacles to the commercialization of Fuel Cell vehicle is the cost of the system. The redox flow FC (RFFC) system , using Polyoxometalate(POM), which is entirely free of any precious metals in cathode, has a low cost potential⁽¹⁾. In this paper, we describe the performance of our RFFC system including the reaction rate and system volume. We conclude that the energy density of RFFC is too low to compare with the standard PEM-FC. We need to develop new high energy density media to apply RFFC system to vehicles.

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In order to realize good fuel economy, smooth acceleration and deceleration, easy drive control required for public city bus, we developed unique vehicle control strategy which controls motor drive/regeneration torque continuously based on accelerator pedal opening angle, and we confirmed its advantage on fuel economy and easy drive performance for bus drivers.

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The "statistical tire model" method, which is used for performance design in the early stages of vehicle development, was applied on estimation of the rolling resistance of tires. The influence of tire size on RRC has been identified quantitatively by analyzing measured rolling resistance of tires that have variation in both its sizes and inflation pressures yet that have the same structure and rubber compound. As a result, a model with good precision was obtained that can estimate the increase / decrease of the rolling resistance with respect to the reference tire if the tire size and its inflation pressure were given. By using the proposed statistical tire model, the quantitative requirement for size selection will be able to be proposed at the initial stage of development, and as a result accuracy of initial design would be enhanced.

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Passenger’s passive motion, results from vehicle motion, impacts on ride quality. So, we built the methodology to explore desirable passenger body motion, under a fixed driving task, by employing inverse dynamics analysis based on optimal control. First, we embedded passenger body model in vehicle model along strict formulation. Next, we developed soft sensor model so that acceleration and jerk can be integrated to the cost function for minimizing by optimal control. Then, inverse dynamics simulation was becoming executable to derive vehicle motion meets to the aiming passenger’s passive motion. Designing passenger motion will lead to the understanding of human perception on vehicle.

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It is shown by eigenvalue analysis that the weave mode, which is one of the vibration modes affecting the straight running stability of the motorcycle, becomes unstable as the speed becomes higher. In this report, we clarify the mechanism of high speed instability of weave mode. From the analysis results of the Energy Flow Method, it was found that the main cause of the instability in the high speed region is the phase delay of the rear tire lateral force term. Furthermore, it turned out that the root cause of the phase delay is an increase in the vehicle speed.

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Recently various types of tire contact behavior measurement method have been developed due to miniaturization of durable high precision sensors. Although it is important to understand the contact characteristics of tire, which is the basis to improve both vehicle dynamic performance and environmental performance, there has been no method that could measure the contact behavior under the transient condition where an input to tire changes according to actual driving condition. In this research, contact characteristics measurement method and visualization technology under transient condition were developed and the difference between developed method and conventional method was presented and discussed.

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Energy Flow Method is Proposed in Order to Discuss the Mechanism of Wobble and Weave modes. In This Paper Detailed Procedures are Given to Use the Energy Flow Method, as an Example for Caster Angle Change. This Method Shows That the Wobble Mode Becomes Unstable Due to a Coefficient for Yaw Rate Force Acting Steering System Increases as Increasing the Caster Angle. And Decreasing Front Tier Force as Increasing Caster Angle. This Causes the Weave Mode Stable.

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Motorcycles have instability modes at high speed range. These are called wobble and weave modes.The reasons of the high speed instabilities have not been understood by now. This paper shows that the detailed mechanism of high speed instability of wobble mode in a context of equations of motion.The Energy Flow Method is applied to Wobble Mode in this discussion, using the informations of Eigen Vectors.

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In this paper, the cornering drag caused by camber angle was analyzed and verified based on simple physical tire model and measured tire data. It has been clarified that the drag generate from camber moment, and the drag coefficient to lateral force by camber angle is larger than that by slip angle. Considering its characteristics, vehicle dynamics in linear region of tire forces was studied. It has been shown that how to use camber thrust to minimize cornering drag, and efficient wheel alignments design where equivalent cornering stiffness vs drag are well-balanced.

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The effect of G-Vectoring Control (GVC) on vehicle-platooning was analyzed using simple cornering scenario and it was clarified that applying GVC on a vehicle-platooning causes the reduction of vehicle distance, or the increase of acceleration change during turning. As the solution for these issues, new longitudinal acceleration control based on GVC is proposed; the additional longitudinal acceleration control to adjust the distance between platooning vehicles before turning and gain adjustment of G-Vectoring Control. It was confirmed by simulation that the proposed method can give the smooth acceleration change on “g-g” diagram without decreasing the distance between the platooning vehicles during turning.

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Masing friction model is indispensable as the physical model of hysteresis phenomena in vehicle dynamics area, such as ride comfort, noise, and vibration. Another phenomenon in vehicle dynamics area, which is supposed to have much to do with friction is the inferior on-center steering feel of Electronic Power assisted Steering (EPS), compared to that of Hydraulic Power assisted Steering (HPS). The paper proposes a method to improve the on-center steering feel of EPS beyond that of HPS by the application of Masing model to EPS control algorithm.

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Using brush tire model, it was proved that slip dissipation power on the tire contact patch at a tire slip angle is equal to the power loss due to the cornering resistance regardless of the distribution of adhesion and sliding regions. The analysis result also shows the dissipation power due to a camber angle is consistent with the cornering resistance obtained from the coordinate transformation. Therefore, the respective dissipation power can be calculated directly as a product of the generated cornering resistance and velocity. Finally, this paper classified the cornering resistance and dissipation power due to longitudinal slip ratio, lateral slip angle, and camber angle, respectively.

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This paper deals with two-wheeled vehicle characteristics of steady state turning considering equivalent compliance for steering and suspension. In order to clarify the dynamics of two-wheeled vehicle at turning, we first measured tire characteristics. A steady state turning test was conducted using these tires to analyze the characteristics of the vehicle. Next, the steer characteristics and side slip characteristics were derived in consideration of the tire characteristics. From the difference between the experimental results and the analytical results, the equivalent tire characteristics were derived the equivalent cornering stiffness of front and rear tires. From these results, it is shown that the equivalent torsional compliance of the steering system and the rear suspension are derived from the relationship of the side slip angle. Finally, it is shown that we can describe expressing the characteristics of steady state turning quantitatively.

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The test damper developed for a micro vibration suppression of a car body can produce a velocity-independence nearly constant high damping force even in a very small velocity range. For selection of optimum damping force for an arbitrary car, it is necessary to establish prediction method of vibration on a car when a damper is installed, and the physical model of the damper itself is required. Previous report elucidated the generation mechanism of damping force and linearization method is described. In this report, vibration response estimation method of a car body is proposed when the test damper is installed This is the method that the vibration of a car body can be estimated from the values of compliances at input point of external force, evaluation point on a car body, coupling points between a car body and test damper, and the value of coupling stiffness. Feasibility of proposed method is examined through FEM simulation of a mock frame and a test damper. As a result, it can be found that the vibration responses estimated from proposed method and calculated by direct analysis agreed well each other. Further, taking applications on an actual car into consideration, vibration estimations in cases of multidirectional input and multi-point-inputs are performed.

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Recently, due to the reduction of engine sounds such as electric cars, the background noise in the passenger compartment of road noise and wind noise tends to be relatively conspicuous. Therefore, in this study, we added pink noise simulating background noise and examined the recognition of engine sound during running. In this paper, following three studies will be discussed: (1) estimation of the effective frequency band for recognizing engine sound, (2) study of improvement of recognition by parameter change, (3) grasp of the relationship between engine sound recognition and driving performance using driving simulator driving task.

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The purpose of this research is to predict both the frequency and peak level of road induced noise from the signals of monocular camera adopted for automatic driving without newly adding sensors for utilizing the prediction result as a reference signal to reduce road induced noise by ANC. Using the monocular camera, both the frequency and peak level of road induced noise is predicted by machine learning from the road surface features which are extracted from road surface images by three image recognition techniques (HOG, CNN, autoencoder).

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In this study, we considered a method for selecting high contributing vehicle body vibration behavior to the interior vibration in time domain at a transient running condition such as passing a bump. As the analytical method, principal component contribution analysis method, that was made utilizing operational TPA method, was expanded as the time domain analytical method. We applied the method to a simple vehicle model running at the imitated transient input condition. As the result, the ability indicating the high contributing vehicle body vibration behavior in time domain at the transient condition was confirmed.

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The characteristic scenario of the Hiyari-Hatto event (i.e., a near-miss incident) wherein a driver is making a right turn is extracted from the Near-Miss Incident Database created by the Smart Mobility Research Center of the Tokyo University of Agriculture and Technology. It is confirmed that in this scenario, there exists a human error: the driver does not notice the pedestrian although it is clearly visible. In this paper, examined about the mechanism of the human error based on the relation between driver’s attention and eye movement, and effect of mental calculation task on driver’s steering operation using driving simulator.

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In assessments of advanced driving assistance systems(ADASs), an index of assessment quality is currently only running distance of field operational tests(FOTs). In this paper, we propose a novel index which expresses comprehensiveness of all the real scenes by classifying features (e.g. road length, road curvature, shape of intersection etc). We also propose a practical method of efficiently designing the assessment scenarios based on the proposed index. The results show that the assessment scenarios cover most of the real scenes.

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Changes in indoor temperature affect arousal level and thermal comfort of driver. In this research, we aim to prevent the drowsy driving of drivers and to improve the thermal comfort. We evaluate the effect of the changing pattern of indoor temperature on the arousal level and thermal comfort of driver based on subjective evaluations, physiological parameters and driving performance utilizing driving simulator. As a result, the arousal level increased and maintained at an alert state, corresponding to the changes in the thermal comfort sensation due to decreasing of indoor temperature, and then it was maintained at a high state, although the indoor temperature rose and the drivers felt comfortable. These results showed that it is possible to improve both the arousal level and thermal comfort of the drivers by control the changing patterns in indoor temperature.

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There are few researches to respond to fluctuations in concentration of bio-methane fuel and load fluctuation of a generator using a co-generation gas engine generator of approximately 1kW. For this reason, in a relatively small scale local production type energy circulation system such as the GET(Gas, Energy, Tambo) system, it is necessary to develop a co-generation gas engine generator which can use the generated unpurified bio-methane gas to accommodate to the load fluctuation. The GET system is a bio-methane gas production paddy field of sustainable resource recycling type, and does not special auxiliary facilities. We have researched by using the bio-methane gas produced from the GET system as the fuel of a co-generation gas engine generator for usage of the electric energy and thermal energy supply to the air conditioning for the greenhouse. We reported a control system which is adapted to the input disturbance (load fluctuation and fuel concentration fluctuation) with the MM_OBSV controller embedded in the electronic governor of co-generation gas engine generator in 1st report. In the 2nd report, to improve the robustness, the input disturbance model of the engine control law was improved. The results were applied to a small gas engine generator, and the result of verification of load fluctuation at a fuel concentration of 100% was reported. This 3rd report is result of verification of load fluctuation at a fuel concentration of 60% to a small gas engine generator.

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The reduction of photochemical oxidant concentration in urban area is an urgent issue. Evaporative emissions of volatile organic compounds (VOC) during refueling process are one of the large VOC emission sources. In 2018, the air environment conscious service station (e →AS) certification system has been established to promote Stage 2 which is a countermeasure to evaporative emission at the time of refueling. In this study, the reduction effect on ozone concentration by the introduction of Stage 2 in the Kanto region was calculated using a chemical transport model. It is suggested that the introduction of Stage 2 leads to the reduction of ozone concentration mainly in the urban area of Kanto.

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In this report, we propose a method to estimate the humidity history where car interior parts are exposed from weather data. We conducted 1year exposure test on the same vehicle in Okinawa, Tochigi and Hokkaido. The automobile interior humidity can be calculated by the solar radiation (ΔQ_SUN), the absolute humidity (H_OUTAIR) of the weather data and the moisture absorption coefficient (a_i), the moisture release coefficient (b_i) of the specific constant of the vehicle. This calculated humidity history exactly matches the actual measured humidity history.

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This paper describes the development of a simplified modeling method to represent fracture of Self-Piercing Riveted (SPR) joints to be used for large scale crash simulation. First, the cross section geometry of the SPR joint was obtained by a 2D simulation of riveting process. Then a detailed 3D SPR model was generated to analyze the fracture mechanism. A simplified SPR model, with shell elements, was developed based on the fracture mechanism. The simplified SPR model well simulated the stress distribution around the joint. The calculated fracture load and fracture mode showed a good correlation with the experimental results.

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This paper describes to develop the finite element (FE) analysis system for evaluating the overall phenomena during a resistance spot welding. Framework of this system is the FE calculation based on the incrementally coupled electrical-thermal-mechanical simulation procedure. In recent years, evaluation of residual stress on spot welded zone is important along with an increase in application of high strength steels to automotive parts. This analysis system is applied to the evaluation for the influence of welding conditions on the residual stress on spot welded zone.

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We constructed a new mathematical model that can express the deposition behavior of electrodeposition paint by using an experimental method that simulates the actual electrodeposition coating environment. The accuracy and validity were verified by comparing the high accuracy electrodeposition coating simulation using the proposed model, and as a result, accuracy has been improved compared to the conventional mathematical model.

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For level 2 automated driving, adaptive cruise control (ACC) and lane keeping assistance system (LKAS) are core technology which require accurate and robust estimation of vehicle lateral and angular deviation in various road environments. In this paper, for lane detection system, we apply moving horizon estimation (MHE) to obtain improved estimation performance even under disturbing situation like junction, for example. The advantage of the proposed method is verified by offline estimation using experimental running data on metropolitan expressway.

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