In this paper, the authors introduce the spark plug for misfire detection system by an ion current. In order to realize high accuracy misfire detection, the signal of the ion current must be larger than that of noise. For maintaining the ion signal through its all lifetime, the figure and the initial dimensions of spark position are derived by an experiment and consideration about degradation in use. Additionally, by observations and a theoretical study, we show a relation between the noise and the corona discharge on the insulator and indicate the method to inhibit the noise efficiently. Finally, the effect of the developed spark plug with these two methods is confirmed with the target engine, and we propose specifications of a spark plug satisfying the condition that realize high accuracy detection by the ion current.

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In order to cope with requirements of lower fuel economy and higher performance，high compression ratio engine，turbocharged downsizing engine and turbocharged lean-burn engine have been developed these days． However，abnormal combustions are possible issues under such high pressure condition from low engine speed to high engine speed． In this paper，the effect of fuel characteristics on the various abnormal combustions is examined． The result shows the effect of fuel components is different and it depends on engine operating condition．

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We proposed a method for analyzing the sensitivity of the nugget diameter to the nominal structural stress, and conducted a fatigue test to verify the results of the sensitivity analysis. The proposed method was compared to the gradient method and confirmed to provide a good solution. The nugget diameter sensitivity Sd differs according to the general load components. The nugget diameter sensitivity SNde to fatigue life showed a good correlation with the estimated value of the standard deviation of the logarithm of the fatigue life, and it was demonstrated that the fluctuations in fatigue life resulting from variations of the nugget diameter can be assessed using SNde.

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We proposed an analytic method for calculating the sensitivity of the plate thickness to nominal structural stress, and quantitatively demonstrated fluctuations in fatigue life resulting from variations in plate thickness. The plate thickness sensitivity St is -1.07 for TS, and -2.00 for CT, and the CT sensitivity, i.e., the peel load that is the main load component acting on the nugget, is twice that of TS, for which the main component is a shear load. Moreover, these values are constant regardless of the plate thickness. When the plate thickness varies by ±5%, the fatigue life fluctuates by -21.6 to 26.0% for TS, and -36.5 to 54.0% for CT.

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Using the nominal structural stress, which is a parameter for assessing the fatigue life of spot welded structures, the effect on fatigue life of changes in the spot weld location, and variations in the plate thickness and nugget diameter, were investigated. With an LP model of a spot welded structure, if the weld locations fluctuate in the flange width direction, the nominal structural stress σns changes significantly, but if the weld locations fluctuate in the pitch direction, the nominal structural stress σns is almost constant and the effect is small. Fluctuations of the weld location in the flange width direction results in significant fluctuations of the fatigue life. With the TS, the fatigue life fluctuates by ±22.8% when the plate thickness varies by ±5%, and if the nugget diameter varies by ±5% about 5 mm, the fatigue life fluctuates by ±10.7%.

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Modern engines have kept increasing number of operating parameters to achieve better fuel economy and satisfy the driver′s desire to accelerate at will. We developed a new gasoline direct injection engine with super high compression ratio which needs intake and exhaust variable valve timing and split injection system to be a Miller cycle engine and also be an Otto when more torque is required. This paper presents some of the control strategies we developed to overcome the difficulty of air and air to fuel ratio control for the engine.

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The ignition timing of homogeneous charge compression ignition (HCCI) combustion engines is the important factor which should be controlled. One of the effective methods for controlling the auto-ignition is a supply of the active species which are produced by plasma. In this study, the production of radical species by nonequilibrium plasma and the promotion of auto-ignition delay time by these species were estimated by using the numerical simulation with detailed reaction models.

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Engine downsizing and higher compression ratio attract attention as a method for improving fuel economy of internal combustion engines. Knocking of an engine is one of the critical factors in determining the engine performance in these systems. In this research, a method for anti-knock control in gasoline direct injection engines was developed based on 3-dimensional fluid simulation and experimental approach. It was clarified that hot spots due to residual gas in the combustion chamber contributed to occurrence of knocking, and a method for cooling the mixture using multiple fuel injection was effective to suppress knocking without increasing smoke emission.

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Natural gas is an attractive alternative engine fuel. Improving thermal efficiency is required for natural gas engines. Although HCCI combustion is considered to be one of the most effective measures to achieve higher efficiency, it is difficult to control its combustion processes. Thus, an experimental study was conducted to utilize spark ignition or pilot diesel injection to assist ignition and combustion of homogeneous natural gas mixtures at a high compression ratio. A rapid compression and expansion machine was used to reproduce and visualize its inherent combustion processes.

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To improve cooling loss of new clean diesel combustion with highly dispersed sprays with restricted in-cylinder flow, heat flux toward combustion chamber was simulated. Moreover, to validate results of simulation and clarify main locations where occurred cooling loss, local heat flux toward combustion chamber was measured by thin film thermocouples. As a result, cooling loss was occurred at sidewall of piston cavity and squish region of cylinder head. This cooling loss was caused by convective heat transfer with reversed squish flow. Then, a new combustion chamber restraining reversed squish flow was designed, and fuel consumption can be improved.

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In this study, NOx emission characteristics were evaluated with the heavy-duty diesel engine when using various FAMEs and hydrocarbon fuels on the assumption of biomass-derived diesel alternative fuels. From this result, the relationship between NOx emission characteristics and fuel properties of these fuels was discussed and effectiveness of paraffinic hydrocarbon fuel was indicated. In the case of paraffinic hydrocarbon fuel, NOx emission could be suppressed to be increased due to the almost same lower heating value per unit volume and its high H/C ratio compared with those of conventional diesel duel.

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The authors utilized pre and after injection to split the heat release for decreasing peak cylinder gas temperature as a strategy. The experiments were conducted in a single cylinder diesel engine for heavy-duty use and operated at BMEP = 0.8 MPa of middle load. The injection timings and quantity of each injection events were changed as parameters. As a result, a multi-injection pattern simultaneously reduced exhaust emissions and the fuel consumption and improved further by the nozzle optimization. The flame movements of the multi-injection in cylinder were observed by means of a high-speed camera and a bore scope.

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Since improvement of fuel consumption and exhaust emissions involve deterioration of combustion noise, it becomes a big issue on future diesel engine from the stand point of improvement of products quality. In this study, simultaneous reduction of fuel consumption, NOx, SOOT emission and combustion noise was tried by using multiple-injection and injection rate shaping. The piezo direct drive injector can control injection shape flexibility. The combination multiple-injection and rate shaping injection made effective noise reduction possible without deterioration of NOx and SOOT emission. Moreover fuel consumption could be improved by multiple and rate shaping injection, advancement injection timing and increasing injection pressure with low combustion noise.

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Recent years, it takes much time to calibrate emission of diesel engine because of its increasing number of calibration parameters. It is possible to save calibration time by applyingModel Based Calibration (MBC), in which engine response model is used instead of actual engine. But MBC is usually applied just for steady state emission calibration because of its difficulty of building models which can predict transient engine response accurately. In this paper, statistical transient modeling methodology which can predict transient engine response is developed to applyMBC for transient emission calibration.

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The objective of this research is to control PCCI combustion with lower emission and higher efficiency due to an artificial heterogeneously of mixture distribution in combustion chamber. In this report, two fuels having different ignition characteristics were injected from slit type nozzle and single-hole type nozzle respectively. The ratio of fuel mass for each injection stage was changed as a main experimental parameter. The shadowgraph of mixture formation and ignition-combustion process were captured by use of high speed video camera. As a result, two stage injection of different fuel has a potential to artificially control PCCI combustion characteristics.

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Mechanism of wear and deformation of nozzle body seat is studied with wear testing machine which was developed　based on a commercially used injection system. Observations of the surface and cross section of worn nozzle body seat　using SEM, and by element analysis of the worn surface with EPMA indicate that the wear of the nozzle body seat is　probably due to formation and exfoliation of oxide scale on the nozzle body seat. The lubricant additives promote the　exfoliation of oxide scale by their absorption and elimination with the oxide scale on the surface of the nozzle body seat.

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Analysis of a behavior of the oil film between piston and cylinder is one of the key technologies for reducing the friction loss in the IC engine. Laser induced fluorescence (LIF) method and particle image velocimetry (PIV) are applied to measure the oil film thickness and the velocity simultaneously in a test engine. Effects of a barrel shape to oil film behavior on the piston skirt are discussed.

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In oil mist lubrication, it is unclear how much oil and air shall be supplied to a certain mechanical systems, especially gears. To clarify the problem, oil mist lubrication to a gear pair has been investigated in the research. The relation between spray characteristics and the thickness of the oil film formed on gear teeth was measured quantitatively. The oil film thickness was measured by LIF based method developed in the research. The oil film thickness increases with time and converges to a certain value, which depends on both supply condition of the oil mist and load torque.

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The aim of this study is to develop a method for detection of driver's intent to depart from the current lane on a general road. We investigated characteristic of driver's eye-movement during preparation of an intended lane departure. The results showed that the time length of gazing the target lane or the side-view mirror just before the start of the maneuver. Based on the result, we discussed a technique of the intention detection and applied it to the experimental data.

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Muscular control algorithm using reinforcement learning, which is supposed to be a mathematical model of learning process in the basal ganglia associated with human postural control was developed to predict occupant postures in pre-crash which could affect occupant injury outcomes in a crash. The algorithm was applied to a musculo-skeletal finite element (FE) model of human whole body. Simulations using the FE model under a condition with a brake deceleration predicted occupant postures in pre-crash.

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This study proposes a platoon control system to detect relative position of vehicle-to-vehicle using moving base RTK and vehicle-to-vehicle communication. This study aims to develop method of high-accuracy observing inter-vehicle relative position without fixed base station, and high-density platoon system. The proposed method uses Moving Base RTK-GPS, and vehicle-to-vehicle communication. The vehicle-to-vehicle communication shares GPS correction signal of all RTK-GPS receivers, so they can obtain each other's relative position without distinguishing a base station and a rover station. In this paper, the proposed measuring method is explained; the platoon control system using proposed measuring method is mentioned; and the validation of experiment using electric light vehicles is reported.

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This study proposes a method of measuring inter-vehicle relative position indirectly using overlap of sensor information of multi-vehicle. Numerous methods of measuring inter-vehicle relative position are premised on direct measuring of target objects. However, there are numerous dangerous situations such that side-by-side vehicles are unmeasurable at several lanes load, parking area and so on. In this paper, proposed method of detecting inter-vehicle relative position indirectly using overlap of sensor information of multi-vehicle is explained; Side-by-Side driving control and Side-by-Side collision avoidance control by proposed method are mentioned; and, the validations of experiments using electric light vehicles are reported.

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In this study, collision-prevention support braking was used as an example, and a methodology for estimating the collision mitigation ratio using this system is discussed. A method for analyzing the collision-mitigation ratio is discussed through a time series Monte-Carlo simulation based on the integrated error of driver and system. First, driver performance in terms of braking timing and deceleration level for collision avoidance was analyzed in a driving simulator when the control timing of the braking-support system was changed. In this analysis, the braking behavior of driver during malfunction of the system and this behavior when the driver was informed about the malfunction of the system were also investigated. Next, a driver model simulating braking operation, when a preceding vehicle started slowdown was constructed. Through time series Monte-Carlo simulations using this driver model, the frequency of collisions with a preceding vehicle and the collision velocity were estimated.

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The algorithm that measures and judges a senior driver's biological fluctuation, which is the activity condition of theacknowledgment functional part of the brain frontal lobe, was developed. It runs with a time series chaotic analysis from the amount of pedal operations of an accelerator and a brake. The evidence experiment of this algorithm was conducted on the elderly people who live in Fuji Kawaguchiko-cho. It proves that there is a strong correlativity between the pedal operations fluctuation and the MMSE (acknowledgment performance inspection) from the observed data.

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This paper describes a relationship between aerodynamic drag on vehicle's backward face and the vortices behind the vehicle and a relationship between vehicle shape and vortices behind the vehicle was clarified by a stochastic analysis. The result shows that there is a vortex ring behind the vehicle and the distance between vortex ring and vehicle′s backward face have relation to aerodynamic drag on vehicle′s backward face. The result also shows the vortex tube transforms by vehicle shape and one of the vortex tube types reduces aerodynamic drag on vehicle′s backward face.

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In order to develop products which satisfy various demands for a limited period, shape optimization technology utilizing CAE attracts rising attention. In this study, we developed an innovative shape optimization technology by using adjoint method in order to reduce computational cost and the difference in the quality of obtained shape, which are the problem of conventional shape optimization method. Present technology was applied to design of engine intake port. As a result, optimized shape equivalent to conventional method was able to be obtained in several iterations.

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Numerical analysis has been performed for turbulent flow in a square duct with periodically arranged ribs on bottom wall by using an algebraic Reynolds stress model and boundary fitted coordinate system which is one of coordinate transformation method. Calculated results are compared in detail with the experiment in order to confirm the validity of the presented model. This kind of turbulent flow is characterized by separated flow which is one of difficult flows to predict. It has been found that the calculation can reproduce reasonably the reattachment point of separated flow including secondary flow vectors. As for Reynolds stresses, although prediction of Reynolds stresses is not perfect, typical features are able to reproduce by an algebraic Reynolds stress model.

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