The research discussed in this paper studied the abnormal combustion which caused a noise of self-ignition. The cause is because the upper part of a piston is impacted to the sleeve on the thrust side, when delayed self-ignition occurs. When engine conditions are low rotation, high load, and high temperature, a noise of self-ignition is generated. On the condition, in order to avoid a knock, delayed ignition timing is required. As a result, the probability that delayed self-ignition will be generated increases. Finally, the probability that a low rotation self-noise of ignition will be generated also increases.

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Natural gas is one of the most promising alternative automotive fuels for its favorable combustion characteristics and availability to address environmental and energy issues. A numerical simulation model has been developed to achieve high efficiency, downsizing and weight reduction in a spark ignition natural gas engine by utilizing an intercooled turbocharging system. The model includes combustion, turbocharging and intercooling processes. An additional model is combined with the model to predict knock occurrence associated with unburned end gas and combustion chamber surface temperatures under both steady state and transient conditions. Thus, the model developed can optimize the spark ignition timing to achieve high thermal efficiency along with avoiding knock.

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Combustion-phasing retard is one of the methods to operate at high load without knocking in HCCI engines. However, too much combustion-phasing retard leads to unacceptable cycle-to-cycle variations of IMEP and PRR. Unfortunately, exact combustion-phasing limits and the behavior of the combustion for retarded operations are not well known. This study investigates the combustion behavior for retarded operations when in-cylinder charge at IVC is replaced with EGR. The results show that there are correlations between CA50 and in-cylinder mass averaged gas temperature at IVC. Then, closed-loop feedback combustion control is applied to the HCCI engine for the combustion control at the limit of combustion-phasing without cycle-to-cycle variations of IMEP and PRR.

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In this study, a comprehensive two-dimensional gas chromatography was employed to analyze combustion products in exhaust gas emitted by SI combustion. From the exhaust gas analysis of SI combustion which used regular gasoline and 10W-30 lubricating oil, a lot of peaks which include many compounds produced by lubricating oil were detected. Therefore, n-heptane as fuel and poly-α-olefin as lubricating oil were applied for engine experiments. From the analysis focusing on linear and branched oxygen containing hydrocarbons with seven carbon atoms, it is suggested that many types of oxygen containing hydrocarbons which is not considered in detailed reaction model exist in exhaust gas.

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In previous reports, robustness control logic for HCCI engine using crank angle sensor and knock sensor was discussed. Recently, ion current sensors have been started to use as a countermeasure against abnormal combustion for downsizing engines and high compression ratio engines. In a view point of the trend mentioned above, application of the ion current sensors to robustness control for HCCI was examined. In case of applied voltage 225V, correlation with indicated mean effective pressure, maximum pressure rise rate and ion signal were low. The cause was estimated that cylinder temperature (thermal ion) of HCCI was lower than one of spark ignition combustion.

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Recently, automatic transmissions have a problem that the calibration of control signals for the shift control system demands an enormous amount of time due to the gear ratio increase. This study proposes the hierarchical and inverse directional design method in order to avoid many trials and errors of the calibration. This method has two model based processes: the first is the design of target driving torque and the second is the control signals design based on the target. Through on-vehicle test our proposed method has same performance as the conventional one.

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In conformity with the JIS D4234 measurement for tire rolling resistance coefficient (RRC), the grading and labeling systems for eco-friendly tires have started. However, this evaluation result does not necessarily indicate correlation with fuel consumption of mode testing, because RRC measurement by the JIS method is carried out under a constant speed condition.With the advanced tire testing system newly developed, tire energy losses of 2WD and 4WD vehicles were estimated under equivalent conditions of mode driving on a chassis dynamometer. Based on this tire testing method,authors proposed the new method that enables to predict tire influences on vehicle fuel economy performance.

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ISO 12405-1,2 specifies international testing standards for lithium-ion batteries for vehicles. In the mechanical shock test is used to determine if the battery is damaged due to the shock imposed when the vehicle runs over a curb or similar minor accidents. Therefore, we conducted minor collision tests against a curb using an actual vehicle and compared the test results with the conditions specified in ISO 12405-1,2. The results confirmed that the impulse wave obtained using an actual vehicle within the range of the test in this study differs from the shape of the impulse wave specified in ISO 12405-1,2.

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The transfer functions between the variables in linear bicycle models of four wheel automobiles, the input to which is steering angle, were examined. The modal response transfer functions between all of the motion outputs, with the exception of front tire slip angle, were found to be independent of front tire cornering stiffness. It is a role unique to rear cornering stiffness to define the above mentioned transfer functions. This concept was also deductively demonstrated, providing additional insight into the physical basis of the proposition.

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Stability factor under force control B was defined in a previous study. By changing B, this paper studies loci of two pairs root under force control. As a result, sum of real parts of two pairs root under force control equals to their real part of root under position control. Further each pair of the roots is almost dominated by front or rear cornering stiffness independently under B >2. Moreover, as vehicle speed increases, the damping ratios of the pair of roots decrease under B >2.

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In RCAR bumper test, the deformation of bumper beam is influenced by bumper engagement. In this test, it is required for bumper beams both to increase energy absorption and to reduce the vehicle weight by designing cross sectional geometries adequately. In this study, the deformation mechanism of bumper beam has been investigated from the view point of the effects of bumper engagement and cross sectional geometries, using numerical analysis. As a result, it is shown that bumper beam with small radius of impact side and wall angle θ_w>90 degrees absorbs large energy in this test, because buckling of cross section is suppressed by the effect of restraining bending deformation of impact face and wall.

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Many papers have been ever presented for brake squeal, moan noise, creep groan noise and so on. Today it is required in brake design to consider the influences of countermeasure for every brake noise, because the moan noise countermeasure will cause sometimes low-frequency disk brake squeal for example. The countermeasure should be derived from the analysis for reducing both brake noises, but there is almost no paper of the relationship research between each brake noise. This paper describes the importance of every brake noise relationship, for example, the relationship between low-frequency disk brake squeal and moan noise.

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The cranking noise reduction which was an important problem of idling stop mechanism loading vehicles was investigated, and the following were clarified. Cranking noise was mainly the radiation sound caused by membrane vibration of a drive plate. Interception of exciting force and cutting off of vibration area of a drive plate were proposed as the cranking noise reduction method in a transfer system, and the effectiveness was confirmed by calculation and experiment.

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Multi-objective optimization simulation to improve combustion noise and fuel consumption simultaneously was previously reported. The report showed that the simulation demonstrated the effectiveness of the optimization of combustion noise and fuel consumption but prediction accuracy of the exhaust emission was insufficient. In addition, precise reproduction of the optimal cylinder pressure waveform which can be obtained from the simulation remained an issue. This report discusses an improvement of the prediction accuracy of the exhaust emissions by employing the detailed combustion model and shows the result of the verification experiment with the direct acting piezo injector.

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This paper deals with a vehicle detection method for realizing a blind spot warning function under various environmental conditions. We introduced a method that is capable of discriminating the target detection objects under dark to bright conditions, and furthermore under various road conditions and occlusions that the image sensor may be affected. The system consists of five functional components: obstacle detection, velocity estimation, vertical edge detection, and final classification. In obstacle detection, a predicted image is generated under the assumption that the road surface is a perfectly flat plane, and then an object is detected based on a histogram that is created by comparing the predicted image and an actually observed image. The paper describes methods to enhance the performances under night conditions and also suppress false detections caused by residue on the lens, which becomes essential for installation on actual road conditions.

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This study clarifies influential factors in a car-to-truck frontal collision using Japanese accident data. The previous injury prediction model has some outlier cases of a car-to-truck frontal collision. In this type of collision, the deformation of a car is large; however, its delta-V explains the injury risk same as in other car-to-car frontal collisions. The risks of car-to-truck collisions are higher than car-to-car collisions because a small car’s delta-V is higher when an opponent truck is heavy. These types of collisions have no difference of odds ratio for injury prediction factors. This indicates car-to-truck collisions and car-to-car collisions can apply to the same injury prediction model.

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The Flexible Pedestrian Legform Impactor (FlexPLI) significantly differs from the conventional EEVC legform in terms of bone stiffness and leg fracture measures. This study first clarified the correlation of peak injury measures between a human model and legform models representing both legform impactors. Since the most significant difference was seen with the leg fracture measures, the mechanism behind the difference was further investigated by using an isolated leg model. The results showed that both the bone stiffness and the use of different injury measures affect the correlation with the human response.

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This paper presents the identificatio technique of the personalized potential map to design the obstacle avoidance assisting control. First of all, the parameters in the personalized potential map which is considered to represent the driver’s risk feeling to environment is learned by using the obstacle avoidance driving data. Next, the reference path is calculated with gradient method considering the vehicle dynamics in the identifie potential field and the avoidance assistance system is achieved based on the obtained path. Finally, the validity of the proposed assistance system is verified

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Authors conducted macro analysis on the characteristics of accidents caused by elderly drivers during day and night. In this analysis, we calculated the normalized ratio based on the number of rear-end collided cases in order to eliminate the effect of the frequency of driving. We revealed, for example, that numbers of accidents increase in each accident type except for rear-end collision as driver’s age increases. We also found that the risk of collisions between elderly drivers and elderly pedestrians is high in case of person to vehicle collisions.

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“Drivers 'Guides to Hours of Service”, announced by MLIT, sets out maximum driving hours, minimum break minutes, etc. to ensure drivers’ safety and improve their working conditions. Paradoxically, compliance with the Guides had been a burden not only for the companies, but also for the individual drivers. With introduction of our new digital-tachograph, we have implemented a new operation system, which, enabling drivers self-management of operation, has brought major decline in incidences of drivers' incompliance with the Guides and cut the accident occurrence rate down to half, from 1.07 per month to 0.53 per month.

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Visual field luminance determines the optimum display luminance necessary for adequate visibility. In this study, we developed a method that estimates the luminance level of a driver's visual field using an illuminance sensor and investigated its actual characteristics. We then simulated the visual field of a driver's seat environment under experimental conditions. In our experiments, test subjects evaluated the optimum display luminance of a car-navigation system under static conditions, with variations added to simulate time of day and weather. As a result, we obtained an equation that predicts the adequate display luminance level based on driver's visual field luminance level.

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As a future safety driving support based on a car driver's behavior grasped by non-contact sensors, general state space modeling and sequential state estimation by particle filter have been used to estimate the car driver's behavior accurately and being in real-time. Face posture to observe outside of the car and both hands motion to operate steering have been employed as the car driver's behavior. Face camera set over the steering and steering camera set above the seat-belt roller are used to capture video images. Robust methods for sudden motion of face direction and mutual occlusion of hands have been proposed.

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This paper discusses a way to detect the driver’s intention to decelerate in a car-following situation. A field observation and an experiment were conducted. In the field observation, the data were collected for analyzing a driver’s maneuvering of the accelerator and brake pedals in order to design a system that can detect the driver’s intention to decelerate. The method based on the covering brake pedal found to be highly reliable. An experiment was conducted to evaluate the influence of the proposed system. The results showed that the system was effective in improving the accelerator release time and brake onset time.

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This paper aimed to model the driver’s risk avoidance behavior in a crossing pedestrian scenario during the normal driving on the test track. We investigated the driver’s avoidance maneuver and his judgment whether he avoid / not avoid the pedestrian from the post experiment interview. As a result, we found that the driver’s risk avoidance behavior can be explained by the time to the conflict point of the driver (TTC) and that of the pedestrian (TTV).

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Our previous study proposed a DCA (Deceleration for Collision Avoidance) as a novel collision risk index, and verified effectiveness of FOCWS (Forward Obstacles Collision Warning System) based on the DCA. The present manuscript proposes a new visual information presentation of the DCA, which simulates a windshield display. Driving simulator experiments are performed to discuss the differences in effect on driving behaviors caused by the difference of the two information presentation methods.

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The test condition for presuming vehicle indoor VOC concentration from the VOC measured value from the parts obtained from the chamber method was examined. As a result of evaluating the influence of solar radiation, the conditions with solar radiation were understood that about 4% of solar radiation loading dose is high as compared with solar-radiation-less conditions. Moreover, . for which the VOC emission factor(diffusion speed) from parts found that the influence of an air change rate(ventilation rate) was great, as a result in order to carry out vehicle indoor VOC prediction realization from a chamber method more, it is required to measure by the air supplying amount of a real vehicle.

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With the shape optimization technology based on the modification of surface geometry of base shape, the final shape might not achieve target performance depending on initial shape. In this study, in order to resolve this issue, we developed topology shape optimization technology by using adjoint method, which can roughly derive the shape near the optimal shape considering target function in design space. Present technology was applied to design of engine intake port to achieve a balance the maximization of flow rate and that of tumble vortex. As a result, topology optimized shape which has various performance according to the weighting factor of cost functions was obtained.

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We explain the temperature control method of the advanced DX system that combines the evaporative pressure regulator (EPR) with the inverter control of the compressor, corresponding to a wide range temperature setting required of the environmental test room. The advanced DX system does not need the re-heater. Therefore, it reduces the energy consumption significantly. We report the results of the simulated energy-saving performance of the advanced DX system compared with the conventional DX system.

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Path planning for autonomous vehicle navigation is one of the most important technologies for the autonomous vehicle. Generally, a path generated by the autonomous vehicle navigation system must be smooth, and it is necessary to be able to compute efficiently since velocity of the vehicle is high. Therefore, in this study, a method to efficiently generate the trajectory based on digital map is proposed. Additionally, we also propose a method to decrease noises in digital map. Moreover, the system overview of our autonomous vehicle will be shown and result of autonomous vehicle navigation demonstration in the Tokyo motor show 2011 will also be shown.

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Recently, technologies related to autonomous vehicles are researched all over the world. For such autonomous vehicles, it is important to extract small obstacles such as curb stone, and it is also necessary to recognize drivable area in omni-direction not affected by occlusions. In this report, we propose obstacle extraction method based on Occupancy Grid Maps to overcome these problems. Moreover, the system overview of our autonomous vehicle will be shown and result of proposed algorithm at a demonstration event in the Tokyo motor show 2011 will also be shown.

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