This study is Heavy Duty Engine and Powertrain development for new model of Quon. The high pressure of the fuel injection pressure for reducing PM. high-boost and high EGR ratio for reducing NOx, also close air management control can provide a higher torque at a low speed of the engine, and a higher power. As driveline, the gear ratio of transmission was changed to aim for improve the fuel consumption and the drivability. Improve fuel economy performance by the reciprocal driving control technology by engine and transmission.

View full abstract

Effect of fuel injection timing on graphitic crystallite size of soot particles from small DI diesel engine was investigated experimentally. The soot particles were sampled from exhaust gas, and its nanostructure was investigated by laser Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM). The soot Raman spectra showed that the graphitic crystallite size of soot obtained at rapid or late fuel injection timing was larger than that of fuel injection timing around 4 ～ 6deg. BTDC. In addition, the size of graphitic crystallite in the soot particles increases with increasing the engine load. These trends were strongly correlated with variation of the graphitic crystallite size obtained from analysis of HRTEM images.

View full abstract

Engine oil dilution can occur because biodiesel fuel (Fatty acid methyl ester: FAME) has lower volatility than petro-diesel fuel. Recently, it was reported that the FAME was broken down to low-molecular structure by cross-metathesis reaction and therefore improving the volatility of FAME. In this study, the improvement of oil dilution was investigated by long-term engine test using the surrogate fuel which simulated FAME after the cross-metathesis reaction. From the experimental result, the dilution ratio using surrogate fuel became about one third in comparison with the case of using FAME only, therefore the oil dilution was improved.

View full abstract

Power generation systems using waste biomass have attracted attention. Biomass gas has relatively low energy density compared to other conventional gaseous fuels. Therefore, a lower stability of combustion and ignition is expected. In this regard, the subject of this research is to achieve the same high thermal efficiency and low exhaust gas emission of turbo charged gas engine while using biogas. In this paper, effects of excess air ratio and ignition timing were investigated, focusing on the combustion and exhaust characteristics.

View full abstract

It is essential to elucidate the effects of pore structure on the pressure loss and flow field during regeneration process of the diesel particulate filter (DPF). In this study, we simulated the flow and regeneration of DPF. Several filters with different porosity were used. One was the reference whose inner structure was obtained by an X-ray CT technique, and the other six filters were formed by changing the porosity. We conducted the numerical simulation of these filters, and evaluated the phenomenon during DPF regeneration. Especially, we monitored time variation of backpressure and time required for regeneration. Based on these results, it is found that during the regeneration process, as the soot amount is decreased, the filter backpressure linearly decreases, which is caused by the oxidation of soot layer. Additionally, as the porosity is lower, the time for regeneration is shorter.

View full abstract

In this study, using carbon particles as model diesel soot, we evaluated the filtration performance of SiC-DPF. We changed the flow volume rate to examine the filtration velocity on the property of soot cake during the surface filtration. The flow rate was from 4.5 to 40.4 L/min. It was found that, as for the filtration performance, the pressure drop increased at higher flow rate. Based on results, we discussed the density of soot cake formed during the surface filtration.

View full abstract

In order to reduce particulate matter emitted from gasoline direct injection spark ignition engine, the key is improvement of the homogeneity with high pressure fuel injection. In this study, air entrainment velocity into spray of high pressure spray from slit nozzle was measured with using constant volume vessel. And, the influence of increasing fuel pressure on fuel-air mixture was investigated.

View full abstract

This report presents knock intensity investigation by using pressure analysis and plug type optical sensor measurements. The pressure oscillation is initiated at early of auto ignition heat release, then, the pressure oscillation intensity grows through the heat release. The pressure oscillation growth is measured by using pressure analysis and 32-directions of optical measurements. As the results, strong knock intensity is generated by following process: i) weak pressure wave is generated by auto-ignition, ii) pressure wave propagates through combustion chamber, iii) pressure wave stimulates auto-ignition near flame front region and amplitude of pressure wave is increased.

View full abstract

The authors investigated the effects of a fuel reforming system installed in an EGR line on engine thermal efficiency in a spark ignition gasoline engine using a numerical simulation. Specifically, we proposed an engine system called Dedicated-Reforming which combines lean combustion in three cylinders and stoichiometric combustion in one cylinder, the exhaust gas from which was utilized to produce hydrogen, CO and other combustible gases by means of a fuel injector and the reforming system. The numerical results indicate that D-Reforming system can achieve higher overall brake thermal efficiency compared with that of a usual lean combustion engine system.

View full abstract

Ignition delay times of regular gasoline (SIP regular gasoline) and gasoline surrogate (SIP gasoline surrogate S5R) consisting of n-heptane, isooctane, diisobutylene, methylcyclohexane and toluene were measured using a rapid compression machine (RCM) in the temperature range 660 - 730 K and the pressure range 3 - 5 MPa at an equivalence ratio of 0.5. The measured ignition delay times were compared with the simulated ones using a detailed kinetic model of the gasoline surrogate. Ignition delay times of both fuels decreased with increasing pressure and ignition delay times of gasoline surrogate were similar to those of regular gasoline. The simulated results were in reasonable agreement with those of the experiments. The kinetic mechanism of the gasoline autoignition under the high-pressure conditions was investigated using the kinetic model.

View full abstract

The System we developed detects knocking by sound signals, which are captured by a microphone. Feature values are calculated with the spectrum analysis from sound data near the TDC. Threshold values for detecting knocking are decided by anomaly detection techniques. Thereby realizing to detect knocking even under a circumference, where mechanical noises exist. Further, the knock index calculated from the measurement results and knocking intensity judged by experts showed the similar trend. From the above results, we conclude that the system is effective for detection and objective rating of knocking.

View full abstract

White smoke emission is observed at tailpipe of diesel engine when unburned hydrocarbons (HCs) are stored on diesel oxidation catalyst (DOC) under low gas temperatures. In this research, relationships among behavior of white smoke emission and the amount or quality of HCs adsorbed on DOC were investigated by change of DOC specifications, such as zeolite content, platinum metal group (PGM) content and Pt / Pd ratio contained as PGM, under two HC adsorption temperature conditions, 120℃ and 180℃. It was clarified that the adsorbed ratio of heavy HCs which have higher boiling point than that of nC16 becomes larger with decrease in the zeolite content at 120℃, leading to a dense white smoke emission at the same amount of adsorbed HCs on DOC. On the other hand, comparing to zeolite content, the PGM content or Pt / Pd ratio has less impact on the adsorbed HC amount on DOC and white smoke emission for both HC adsorption temperatures. In addition, it was assumed that the zeoliteless DOC has a higher catalyst activity compared with zeolite-containing DOC under the gas temperature of 180℃, which results in the drastic reduction in white smoke emission.

View full abstract

Diesel engines have a high thermal efficiency, but 20-30% of the input heat quantity is lost as the cooling loss. It is important to investigate the mechanism of wall heat transfer with impinging flame on the wall in improving the thermal efficiency. Therefore, in order to investigate the correlation of diesel flame and the wall heat loss, chemiluminescence photography, luminous flame photography and measurement of heat flux were carried out by using a wall insertion type constant volume vessel.

View full abstract

Generally, soot emission is increased in smaller-size bore diesel engine than larger one because spray-impingement on cavity wall is more significant. From 1st. report to 3rd. report, required conditions to maintain emission similarity for different sized engines have been verified to improve soot-NOx tradeoff in a small bore engine. In this report, effects of bore size and injection conditions on heat transfer coefficient are clarified experimentally and theoretically from a viewpoint of fuel efficiency. Furthermore, the relation between fuel efficiency and engine size are correlated quantitatively based on new equation of heat transfer coefficient.

View full abstract

Spray combustion simulation for various market diesel fuels is performed. Simulation is validated against experimental data of constant-volume spray combustion in terms of ignition delay time and flame position. We employ a skeletal reaction model developed by Ranzi et al. (2014), which includes reactions of n-cetane, methylcyclohexane and 1,2,4-trimethylbenzene. Surrogate fuels are formulated to reproduce the properties of the market diesel fuels. Simulation predicts experimental data of ignition delay time and flame position well, except that it underestimates variation of ignition delay time among fuels and predicts flame position further from the nozzle in the begining of combustion.

View full abstract

Marine diesel engine have a high thermal efficiency compared to passenger car diesel engine. Consequently, it is possible to improve the efficiency by applying marine engine technology to passenger car engine. For that, similar applying of the combustion process of marine engine is effective. Recently, the study for generalization of the combustion process based on theory on spray similarity has been conducted. However, basic studies focusing on the internal structure of the diesel spray in detail have not been yet conducted. Therefore, the purpose is comprehending the diesel spray characteristic similarity from spray internal structure quantitatively by using LES analysis. In this study, calculation accuracy is validated by LES analysis using improved WAVE-MTAB model. In addition, the reproducibility of similar spray characteristics are confirmed by LES analysis using WAVE-MTAB model and theory on spray similarity.

View full abstract

Diesel engines equipped with Diesel Particulate Filter（DPF） system have a significant problem regarding oil dilution caused by post injection during DPF regeneration. In this paper, the measurement of oil dilution rate using a carbon balance (CB) method were established at first. Then, in order to clarify the detailed mechanism of oil dilution, the effects of injection pattern and fuel properties on oil dilution and fuel evaporation in crankcase were experimentally investigated. The experimental results show that the split injection is effective to reduce the oil dilution especially at high ambient gas temperatures, although the effect becomes smaller with decreasing the ambient gas temperature. Furthermore, the fuel components strongly affect the fuel evaporation rate in the diluted oil.

View full abstract

Previous research shows that the performance of DMFC can be improved by applying the porous flow fields which can supply reactants evenly to the whole surface of electrodes compared to the operation with conventional straight groove flow field. This current paper describes the investigation on the performance of DMFC employing another porous flow fields made with sintered metal fiber which can also supply reactants evenly. The experiment results show that increasing the porosity of the new flow field decreases the reaction resistance due to the improved reactants supply and increasing the cell set bolt torque decreases the cell resistance.

View full abstract

In this paper, effects of the rotating wheel gyro moments on vehicle handling dynamics were considered in a three degree-of-freedom model that roll motion coupled with plane motion. Transfer functions of yaw rate and roll angle to steering angle were formulated and the root loci varied by rotating wheel gyro moments were analyzed. Moreover, gyro effects of rotating wheels on step responses and frequency responses to steering inputs were explored by numerical simulation. Based on the theoretical analysis and the simulation results, it can be concluded that the gyro moments of rotating wheels have contributions which can’t be ignored to the vehicle handling dynamics.

View full abstract

„Moment Plus(M+)“ is the yaw-moment control based on lateral jerk information, and the effect of M+ on lane change maneuver was studied from driver’s controllability point of view. The relation between steering speed and yaw acceleration was used as the index to evaluate the controllability of the vehicle. It was confirmed that M+ can improve the linearity of this index by combining with G-Vectoring Control, which is the longitudinal-acceleration control based on lateral jerk. This result indicates that M+ would be useful to reduce the steering control effort for lane change.

View full abstract

In order to accelerate the expansion of a large and narrow tire possessing superior ecological performance towards next generation eco-friendly vehicles, authors have developed and evaluated exclusive technologies for the enhancement of large and narrow tire technologies. By utilizing the exclusive technologies, a series of intermediate-size large and narrow tires as a new trend is proposed for encouraging easier adoption of large and narrow tires not only for the next generation of eco-vehicles under development or planning but also for a derived vehicle with small modifications..

View full abstract

This paper describes a motor noise design for the newly-developed electric powertrain with mechatronical integration structure. The powertrain aiming for light-weight to extend a driving range of EV by mechatronical integration structure which integrates strong electric parts with motor has a disadvantage for motor noise due to the increase of the surface area. The design method for electromagnetic force using vibration-acoustic transfer function has been developed to reduce the force. The method helped to take a balance of motor noise and light-weight by bringing a significant reduction of electromagnetic force of the motor.

View full abstract

In the point of view of the vehicle motion perception and the source perception of an engine，the acceleration feeling and exhaust notes etc.， for example，the waveform design for the suitable timbre was developed by using of the DSP technology．This synthesizing processes were based on the sine wave composition method and the frequency filter these parameters were controlled temporally．For the appropriate sound image localization of sources，the positions where the electro-acoustic transducers should be located in a vehicle cabin were optimized individually．Thereby the distinct moving sound image synchronizing the engine revolution was accomplished．This technology was adapted for a new sports car with a V8 gasoline engine to fuse its original engine sound．

View full abstract

The method to reduce the scattering of the response level of frequency response function (FRF) without reducing scattering of each parts uncertain characteristics is investigated. To find the solution which can minimize both mean and standard deviation of the response level of FRF, the response surface model that can express the mean and the standard deviation is derived. The solution which minimized the mean and standard deviation is applied to the full vehicle model. And it is confirmed that the scattering range reduced than initial condition. By using this method, the robustness is enhanced without controlling uncertain characteristics of each parts.

View full abstract

The present damper developed for a micro vibration suppression of a car body, that uses an oil hydraulic pressure control valve for generating damping force, is able to produce a velocity-independence nearly constant damping force unlike an ordinary viscous damper and hence to produce a large damping force in a very small velocity range. However, a particular account of the generation mechanism of a damping force has not been given so far. This paper presents firstly the derivation of equation for attenuation characteristics; nonlinearity of the present damper with a built-in oil hydraulic pressure control valve as an attenuation mechanism. Next, linear attenuation coefficient equivalent to the non-linear damping force is driven using a describing function method and then the validity of modeling of damping mechanism and its linearization technique is verified on the basis of comparison of simulations with experiments.

View full abstract

Demand of design low noise and vibration products become higher in recent years. It is however difficult to manage vibration thorough broad band frequency and in the early stage for developing new products. To reduce noise and vibration levels we have two choices; one is controlling natural frequency characteristics which is referred to “mode” and the other is controlling base line of frequency response which is described by “wave”. Then it is important to have these two viewpoints to control the noise and vibration. This paper proposes a two-step design for designing low-vibration structures based on both views of vibration. In first step base line (average) behavior of structures is considered by using the view of wave and the design based on modal behavior is used in second step. Also, noise and vibration analysis methods for employing in each step design is discussed. Moreover, it is demonstrated that the proposed two step design is useful to design low-vibration structure through broadband frequency by using vibration energy propagation analysis such as Statistical Energy Analysis and Structural Intensity Method (SEA and SI), in which analytical SEA for the first step design and SI for the second step design.

View full abstract

The impressions of driver and passengers in acceleration of a vehicle are changed by the running sound and driving scene, etc. In this study, the temporal variations of the impression to the acceleration feeling are revealed by subjective evaluation focused on the acceleration section using the acceleration sound as the audio information. Next, the impressions of acoustic parameters changed by the time variation in acceleration are estimated, and the sensibility models are constructed for the impressions.

View full abstract

This study was focused on a crankshaft of thin-shaft and long-stroke design for which the sum of main journal radius and crankpin radius is smaller than crank radius. It was clarified by intensive vibration analysis that there is a coupled mode of opening deformation of No.1 crank throw and rotational deformation around the fulcrum of No.3 main journal, which thereby increases bending deformation of crankshaft and pulley spokes. To reduce this coupled mode, a method was proposed that can reduce crankshaft vibration without increasing the weight or modifying the crankshaft, by suppressing pulley spoke bending deformation. This reduction method was verified that the crankshaft vibration can be reduced 16% by increasing the bending stiffness of pulley spoke 16%.

View full abstract

Effects of shapes in angular acceleration curves during head rotational impact on cumulative strain damage measure (CSDM) and strain distribution were investigated to elucidate critical factors for better brain injury prediction by using a human head finite element (FE) model. A constitutive model of brain parenchyma taking account of strain rate dependency and characteristic features in unloading process was applied to the head FE model. The results suggested that not only the peak value of loaded angular velocity or angular acceleration but also the duration of impact could be a critical factor for brain injury prediction.

View full abstract

The method of calculating the head trajectory in three dimensions within the passenger compartment using the head and vehicle’s acceleration and angular velocity in their respective local coordinate systems was constructed. To verify this calculation method, a crash simulation in LS-DYNA was conducted to compare the calculated result and the simulated result. The possibility of obtaining the head trajectory in the global coordinate system from the head and vehicle’s acceleration and angular velocity in their respective local coordinate systems using LS-DYNA and MADYMO was also investigated. The head trajectory of a vehicle occupant with respect to the vehicle as well as the global coordinate system can be obtained using these methods.

View full abstract

For object (e.g. pedestrian) detection, large scale database measured via an in-vehicle camera have been proposed. In this report, we visualized statistical characteristics for the databases by using non-linear discriminant analysis (NDA) and presented the pedestrian recognition accuracies based on the estimated posterior probabilities in the visualization by using NDA

View full abstract

Risk predictive driving is essential to maintain safety while passing a parked car (passing-a-parked-car scenario), which is one of typical high risk traffic situations because a pedestrian might suddenly dash out from behind the car. In this study, we propose a novel risk prediction method for generating a reference trajectory in the passing-a-parked-car scenario. This paper defines the risk as collision speed with AEB (Autonomous Emergency Brake) against a simulated pedestrian dashing out from behind the parked car. Because the collision speed is theoretically determined depending on vehicle position and speed, the risk is defined in vehicle state (position and speed) space. Plotting vehicle state sequences of actual driving data in the space, we quantify risk at each moment in passing-a-parked-car scenario and show that vehicle state sequences of risk predictive driving can be plotted in zero-collision-speed region in the space.

View full abstract

Autonomous Emergency Braking systems have been already introduced to the markets to realize road traffic zero fatalities, and humans positively evaluated the functions of such assistance system. However, such assistance system reaches its limit when there are unexpected moving obstacles appearing suddenly from poor visibility area, such as a corner of intersection, and a space behind a parked vehicle. This paper focuses on a parked vehicle overtaking scenario which an occluded pedestrian suddenly might intend to cross a road, and a risk predictive shared deceleration control system which can prepare and avoid for a hidden collision risk is proposed. Under a driving simulator experiment, we investigated its functionality and effectiveness of the proposed early intervention support.

View full abstract

The purpose of this study is to evaluate the occupant protection performance of infant seats in infant-carrying vehicles that comply with the guideline. Sled tests were carried out with child dummies in frontal impact configuration. Delta V of 30 km/h crash pulse was used. The influence of bag positions and seatbelt anchorage positions were investigated. Injury values were compared with injury reference values given in corresponding standards and the literature. All injury values were below the reference values. Differences in bag position and seat belt anchorage position had little influence on injury values in a series of tests.

View full abstract

This paper presents an autonomous vehicle control that reflects individual driving characteristics based on the model predictive control with personalized cost function. To realize this autonomous driving, driving data of various drivers are collected through experiments on a driving simulator (DS) at first. Secondly, parameters of cost function of model predictive control are estimated so as to reproduce the characteristic of individual driver. Finally, the proposed method is implemented on DS and the validity of the proposed method is verified through experiments.

View full abstract

In this study, wind tunnel tests of a simplified car model have been conducted to obtain reference data for validation of vehicle aerodynamics computational fluid dynamics (CFD). A model with smooth rear-top shape, which did not fix the separation point, was chosen for the CFD validation specifically to validate the predictions of boundary layer development and flow separation. Additionally, an aerodynamic appendage like a spoiler was introduced as a geometric variation to promote flow separation. The tests measured six components of aerodynamic force, surface pressure, and surrounding flow field. This study reported on relevant aerodynamic phenomena and quantitative results.

View full abstract

Recently, it is reported that the atmospheric pollution levels of particulate matter (PM) are not decreasing despite the introduction of stricter vehicle emission regulations. Vehicle emission measurement under real driving conditions (RDE) by a portable emissions measurement system (PEMS) is attracting attention. Miniaturization was important in order to install such analyzers in a narrow space as well as high accuracy. A new on-board PM analyzer was developed in order to match miniaturization requirement. High performance of the PEMS PM was ensured before RDE tests. RDE measurement of light duty vehicles were performed by utilizing the PEMS PM.

View full abstract

In black bolts for motorcycles, both fastening function and appearance quality are required. However, today there is no method that satisfied those requirements because of regulation for environmentally hazardous material. In this study, a new blackening method that satisfies all requirements including appearance has been developed by taking advantages of the color of chemical conversion film using trivalent chromium and the dip-coating that is considering to the weakness of each treatment by the advantages of each.

View full abstract

The purpose of this study is to visualize strain and crack propagation in high strength steels (TS: 590MPa, 980MPa). A new, simple test for crack propagation has been defined in which strain ratio is measured by multi-camera digital image and FEM analysis. The study shows that the direction of crack propagation changes with material and shape. The crack area predicted by FEM has been validated by simple physical test results.

View full abstract

Relation between nominal stress range and temperature increase at center-hole edge of plates with and without a weld bead was studied through combining elasto-plastic stress analysis under cyclic loading with heat conduction analysis of plastic energy dissipation. The temperature increases at the hole edge are relatively small in low nominal stress range, and begin to increase remarkably in higher nominal stress range. The temperature increase at the hole edge of the plate with a weld bead is little influenced by the plastic energy dissipation around the edge because of small plastic deformation around the edge especially in the weld bead.

View full abstract

For the ELV directive in EU, the Sn-Cu lead-free solder alloy is used in automotive electronic components. In the future, these are made high-temperature operation by the next-generation semiconductor devices. Therefore, the further improvement of the reliability is required in the Sn-Cu lead-free solder alloy. In this paper, tensile-tests were carried out using the Sn-Cu-Ni lead-free solder alloy. The result was used for consideration about the high-temperature deformation mechanism. As for the Sn-Cu-Ni lead-free solder alloy, the stress exponent becomes >3. This result shows that the deformation mechanism is the dislocation creep.

View full abstract