The performance of the laser smoke meter whose principle and structure were presented in the first report was assessed on engine dynamometer and on-vehicle testing. It was confirmed that the soot mass concentration measured by the laser smoke meter coincided well with the paper filter smoke meter measurements. Accumulated soot masses calculated from the instantaneous soot concentration data showed the good correlation with the filtered PM weight measured by the micro-dilution tunnel. The laser smoke meter was proved to have a sufficient performance for on board measurements application to investigate particulate breakthrough when Diesel Particulate Filter suffered damages.

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It is research of piston pin noise of press fit type. Piston supporting system can be roughly divided into floating type called “full-floating” and press fit type called “semi-floating”. The semi-floating system is often used for its cost advantage. This type of supporting system, on the other hand, is more likely to cause piston pin noise. So, in this research, the goal is piston pin noise level of semi-floating system reduce to the same level as full-floating system, via clarification of mechanism of piston pin noise and optimization of piston shape. First of all, in this report, the aims are to be cleared oil behavior at piston pin noise occurred with visualization. As a result of visualization, it was cleared that oil came rushing out from pin hole via groove and doesn’t reach to piston hole from undersurface of piston land.

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In this research, it is a goal to clarify the mechanism of piston pin noise for the press fit type. CAE analysis and engine measurement for understanding of piston and piston pin behavior were conducted. As a result of each approach, it was made obvious that the pin noise is composed of the collision between piston and piston pin and the piston slap. And the relationship between the oil effect (1st report) and the piston and piston pin behavior was considered. It is suggested that the improvement of lubrication in piston pin hole reduces the piston pin noise level. Concerning the results of the CAE analysis, it was clarified that they have high correlation with actual engine behavior. So the CAE analysis was useful for the optimization of piston shape with the good piston pin noise level.

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In this research, it is a goal to reduce the piston pin noise for the press fit type as same level as full floating type. It is clear from the mechanism analysis of the pin noise that an oil film flow inside a pin boss is an important factor for pin noise reduction. It is also clear by using oil film simulation that pin noise is extremely highly correlated with peak radial acceleration of the pin behavior. The pin noise of press fit type is reduced to the same level as full floating type by applying pin boss form to which evaluation parameter becomes the optimal to a piston.

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A novel 0-Dimensional cycle engine simulation has been developed through a series of our studies. For a whole range of operating conditions, it can predict well the engine performances such as torque, combustion noise, NOx emission, and so on. In that simulation, heat transfer through engine cylinder was evaluated by Woschni equation, which has been widely used in a general 0-D simulation. However it is questionable regarding the prediction accuracy because in-cylinder flow motion and fuel spray flow along the wall were not directly considered in that equation, although both of them have crucial impacts on heat transfer phenomena. In this study, the effect of in-cylinder flow on the heat transfer has been modeled based on the theory of plane turbulent boundary layer. In addition, the effect of wall-impingement of burning spray has been modeled by the similar formulation considering spray jet motion. Comparisons of results of 3-Dimensional simulation employing a precise heat transfer model reveal that the proposed models can well reproduce heat transfer process against varied fuel quantities, in spite of simple 0-D simulation. Resultantly, the effect of raised injection pressure on fuel economy can be also predicted well compared with measurement.

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Three of in use heavy duty diesel vehicles complying with the Japanese new long term emission regulation with Urea SCR were tested on a chassis-dynamometer. All of them emitted a large amount of NOx emission due to catalysts deteriorations. One of the reasons of the deteriorations is HC poisoning of SCR catalyst, and it could be recovered by 30 minutes or more high load operation. But NOx emission improvement for it decreased at the Urea SCR vehicles of more than 100,000km or more driving, as pre-DOC's were poisoned and NO₂ formation was inhibited.

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This study investigated the mechanism causing abnormal combustion accompanied by pressure oscillations during the gasoline HCCI combustion using an optically accessible engine. The results revealed that the pressure rise rate was increased by advancing the ignition timing and increasing the equivalence ratio. It addition, it was found that stronger pressure oscillations occurred as the maximum pressure rise rate increased. The results indicated that autoignition began locally and gradually spread throughout the entire cylinder. However, under a condition where pressure oscillations occurred, locally initiated autoignition caused rapid ignition of unburned fuel at multiple locations simultaneously in the process of gradually spreading throughout the cylinder.

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The piston with high compression ratio and late IVC were combined in order to improve the fuel consumption with maintaining the peak firing pressure lower than the mechanical constraints. In addition, the change in the combustion process was investigated by using numerical calculation to find the emissions deterioration process with higher compression ratio. From this investigation, revised combustion chambers were designed in order to improve the exhaust emissions characteristics. As the results, it is not only numerically but also experimentally confirmed that combination of retarded IVC timing and one of the revised combustion chambers can achieve remarkable improvement in both exhaust emissions and fuel consumption.

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In order to reduce soot emitted from Direct Injection Spark Ignition (DISI) engine, the key is to figure out a soot formation process which is timing during combustion and the location in a cylinder. In this study, the soot formation process was revealed by a piston fuel film analysis and soot spatial distribution analysis which were measured by an optically accessible engine. High density of soot is not located on the piston cavity but in the special area of the exhaust side combustion chamber during fast idle operation. In addition, the soot formation continues to increase as time goes on.

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NH₃ has been used in the process of denitration, such as urea SCR. In recent years, because of tighter control on exhaust emissions from diesel-powered vehicles, it becomes all the more important to reduce emissions such as NH₃ and NOx. Therefore there is a need for real-time measurement of NH₃ from the point of view of environmental protection and the improvement of the denitration efficiency. The purpose of this study is to establish the 2D concentration measurement technology of NH₃ using CT - tunable diode laser absorption spectroscopy. The characteristics of 2D measurement concentration of NH₃ were analyzed using engine exhausts. It has been demonstrated that this method has a potential to be applicable to the real-time 2D measurement of the urea SCR process.

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2D temperature and concentration distribution plays an important role for the combustion structure and the combustor efficiency in engines, burners and so on. In this study, the theoretical and experimental research has been conducted in order to develop the noncontact and fast response 2D temperature and concentration distribution measurement method. The method is based on a computed tomography(CT) method using absorption spectra of water vapor at 1388nm. The CT tunable diode laser spectroscopy methods were applied to engine exhausts and burners to measure 2D temperature distributions to discuss the accuracy and the special resolution.

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This paper discusses an electric generation control method applying a model predictive control (MPC) for a series hybrid vehicle (HEV). In the MPC, an optimal control method minimizing an evaluation function including both energy and drive-feeling was utilized. A function dependent on the vehicle speed was introduced into the evaluation function as a target drive-feeling. By describing the engine power model as linear differential equations, the optimal trajectory over the prediction horizon was derived analytically. A vehicle control module (VCM) installed the MPC with the drive-feeling function controlled the generation system in the HEV. It was shown that the performance of the new electric generation control became excellent through driving tests.

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The purpose of this research is to clarify the mechanism of the instantaneous vehicle lateral acceleration. We have led the outbreak factor of the vehicle lateral acceleration, by studying the rotation center of rigid body and the turning center of the center of gravity. The cause of vehicle lateral acceleration is explained clearly, and the dynamic behavior can be shown by a diagram. Applying this study to J-turn simulation, we have shown a vehicle trace as a body slip angle and a vehicle motion state in a diagram.

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This paper tried to reproduce driver’s manipulation which varies depends on driver’s intention. For simulate driver’s control, the driver model is usually used. Though, commonly used driver model, like look-ahead model, sets up its characteristics for operation under certain driving tasks beforehand. Under the hypothesis that driver deliberately select the terminal vehicle movement so that his or her dexterity of driving is represented the degree of terminal set, nonlinear optimization technique is employed. Lane change simulation shows the order of terminal condition fixes vehicle path. Experiment supports the hypothesis on this case to some degree.

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Tire models take an important role in the design and analysis of vehicle dynamic performance and in the development of electronic control systems such as ESC. In this study, a tire model has been developed based on the Magic Formula that requires less data without loosing a good descriptive ability of basic tire characteristics. The tire data consist of understandable physical parameters for engineers. Many internal parameters are determined either by finding average values or by deriving from relevant parameters.

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The electric vehicle which is one of the zero emission vehicle is aimed at the acceptable thing widely favorably to the market and high performance, it is found in the quietness to assume it an attractive vehicle. A motor noise is famous for the representative vibration and noise phenomenon of the electric vehicle. A motor noise decrease has the measures method in the body and the chassis, but making low vibration of the motor which is source of vibration and noise is important. This paper introduces the occurred mechanism of an order frequency becoming the problem and Analytical technology to predict high-precision motor vibration. In addition, this paper introduces the study result and the mechanism inspection result to reduce the motor vibration which aimed at a motor fabric and the specification such as slot combination or the dimension by the experiment.

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In this research, for the purpose of proposing comfort automobile acceleration sound, similarity between automobile acceleration sound and musical instrument sound with comfort feeling is evaluated based on subjective and objective evaluation. First, the similarity of spectrogram in the acceleration sound and the musical instrument sound is observed on visual. In particular, the acceleration sound of sports car with a reputation for sound quality is similar to stringed instruments based on SD method. Next, an auditory model is structured for psychological comfort based on subjective evaluation and spectrum analysis. Higher harmonic components contribute for comfort of the acceleration sound.

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Since use of seatbelt is critical for passenger safety in crash, installation of seat belt reminder (SBR) for passengers is going to be one of items in the Japanese New Car Assessment Protocol. This paper describes establishment of the assessment procedure of the effectiveness of SBR on the passenger belt use. We proposed the model of how SBR works in which there were two pathways, one directory affected on the passenger to induce a voluntary belt use and the other facilitated the driver to request the passenger to use. Based on this model, we designed a series of experiment where the participants assessed the probability of requesting the belt use as a driver, the probability of the voluntary use as a passenger and the probability of belt use by the request from the driver. We examined various designs of SBRs. The results showed that the effectiveness of SBR could be classified as the followings. The SBRs given to either only the driver or to only passenger visually, the SBRs that are the same visual condition but adding the auditory signal, the SBRs given both the driver and passenger visually, the SBRs given both the driver and the passenger both visual and auditory signals. The assessment score can be decided based on the above characteristics of SBR.

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Authors investigated the quantitative evaluation of Adaptive Driving Beam (ADB) by means of simulation program which reproduces the virtual traffic situations in a computer. We selected four typical pedestrian accident patterns on a straight road and decided the necessary parameters for calculation. As a result, in case of low beam headlight, there occur many pedestrian accidents crossing from the right side seen from the driver's viewpoint. Replacing low beam headlight with ADB enables the reduction of accidents. Furthermore, it is revealed that suppressing the vehicle velocity would be a useful countermeasure to reduce pedestrian accidents.

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Authors are developing A Survey Simulator to Evaluate Safety Systems (ASSESS) that virtually reproduces a real road environment and traffic flow in which vehicles run autonomously in the virtual space generated by the computer. In this study, the effect of ADB (Adaptive Driving Beam) was evaluated by using ASSESS. We revealed the benefits of ADB in the situation of ordinary driving during nighttime.

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We investigated whether excessive dependence on the system occurs and whether the difficulty for recognizing each alarm function occurs when a vehicle was equipped with two driving support alarm systems compared with a single driving support alarm system, using a driving simulator. When the different sound was used for each alarm system and each alarm sound was designed in consideration of drivers' mental model related to the collision to the preceding car or lane deviation, the braking or steering reaction time to alarms was not prolonged and the risk-avoidance behavior did not worsen when two alarm systems were used, compared with a single alarm.

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This paper describes a longitudinal study on car-following behavior of elderly and non-elderly drivers. We conducted field experiments using an AIST instrumented vehicle in one year and about five years later. The AIST instrumented vehicle was equipped with various sensors and a driving recorder system to measure the vehicle velocity and the relative distance and speed to a lead vehicle. We evaluated distributions of time headway and an acceleration rate according to the movements of the leading vehicle. The results suggested that the time headway of the elderly drivers was longer in the second experiment than that in the first experiment. In contrast, the time headway of the non-elderly drivers was somewhat shorter in the second experiment. The acceleration of the elderly drivers was stronger in the second experiment when the headway distance was opening. Finally, we discussed the changes of the car-following behavior with aging from the viewpoint of controlling task demands.

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The improvement of fuel efficiency is one of the most important issues in the R&D of powertrain systems. This paper describes a new concept for measuring fuel consumption in real-time, “exhaust flow-AFR method”, which utilizing raw exhaust gas flow rate and exhaust air-to-fuel ratio (AFR). An ultrasonic exhaust flow meter which can measure a wide flow range with no pressure loss, and a fast response zirconia sensor which can be installed onto the exhaust pipe directly were adopted. The exhaust flow-AFR method showed a good correlation with the carbon balance method as a reference under some test conditions. The method also showed short rise/down time and the measurement result of “zero” during fuel cutting as expected.

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