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We have developed a system for automatic deceleration upon entering curves to prevent collisions on tight curves on high-ways. The navigation system is used to determine safe speed negotiating the curve, defined as a speed that will keep lateral acceleration within a settled value. The navigation system sends the curve radius to a controller, which calculates the safe speed for the curve. The controller then sends the speed command to the ACC system, which adjusts the vehicle speed. One of the important features in this system is the estimation of the vehicle position, in terms of its distance from the curve entrance. Navigation systems have a certain amount of dispersion in positional accuracy. A front camera is used in our system to decrease this dispersion. This camera detects lane markers (white lines, raised pavement markers, etc.) using our line recognition technologies1).

Balancing between dependability and cost-effectiveness is essential to promote X-by-Wire systems in the next decade. To achieve this goal, we have so far proposed a network centric architecture based on a concept of autonomous decentralized systems, where if one node fails, the remaining normal nodes autonomously execute a backup control to maintain the system's functionality, as well as a membership middleware indispensable to this architecture to ensure the consistency of the node status information among all nodes. In this work, we implemented membership middleware on a hardware and software platform equivalent to one assumed to be used in actual X-by-Wire systems. This paper describes the implementation details and performance evaluation result, and shows that membership middleware and a real-time critical application can coexist within one microcontroller.

Suspension is an important chassis part which is vital to ride comfort [1]. However, it is difficult to achieve our targeted comfortability level in a short time. Therefore, improving efficiency of damper development is our primary challenge. We have launched a project which aims to reduce the workload on developing dampers by introducing analytical approaches to the improvement of ride comfort. To be more specific, we have been putting effort into developing the damping force prediction, the vehicle dynamics prediction and subjective rating prediction. This paper describes subjective rating prediction method which output a subjective rating corresponding to the physical value of the vehicle dynamics with deep learning. As a result of verification using objective data which was not used for learning process, DNN (Deep Neural Network) prediction method could fairly precisely predict subjective rating of the expert driver.

We propose a combined battery system (CBS) for low cost electric vehicles (EVs) to enhance battery life. The EVs popularly called as Neighborhood Electric Vehicle or Low-Speed-Electric-Vehicle are spreading in developing countries. Conventionally the EVs batteries consist of high energy density cells, and we call it as energy cells (EC). A major issue with the EVs is high operational costs mainly due to high battery cost and short lifespan of the ECs. In this study, we develop a CBS consisting of a combination of following two kinds of batteries: i) EC which is the main energy source for the EV, and ii) a battery having high power density also called as power cells (PC) which is more suitable to bear high charge-discharge currents. The key feature of the proposed system is to minimize the size of additional battery by using our high power lithium ion battery. We performed experiments to estimate EC life for several capacity values of the PC.

The increasing number of controllable parameters in modern engine systems has led to increasingly complicated and enlarged engine control software. This in turn has created dramatic increases in software development time and cost. Model-based control design seems to be an effective way to reduce development time and costs and also to enable engineers to understand the complex relationship between the many controllable parameters and engine performance. In the present study, we have developed model-based methodologies for the engine calibration process, employing engine cycle simulation and regression analysis. The reliability of the proposed method was investigated by validating the regression model predictions with measured data.

In this paper, a newly developed three-dimensional (3D) bird's-eye view map drawing technique for car navigation systems is described. Conventional navigation systems give pseudo-perspective views which can not express ruggedness like hills and valleys. Our newly developed navigation system can display undulation of the land from viewpoints above and behind the current position, so that ups and downs of roads along with the driver's destination can be seen easily. The 3D-road map is not only effective during navigation but also during route planning, because it assists in searching for fine views before travel. In order to achieve the 3D-map view, we developed graphics software libraries, which work on a 32-bit RISC processor and on a low-cost graphics accelerator LSI with texture mapping capability. The graphics software libraries are constructed with three stages, the perspective projection stage, visible-surface determination stage, and rendering stage.

Mixture formation and the ignition process in 4 cycle 4 cylinder spark ignition engines were investigated, using an optical combustion sensor that combines fiber optics with a conventional spark plug. The sensor consists of a 1-mm diameter quartz glass optical fiber cable inserted through the center of a spark plug. The tip of the fiber is machined into a convex shape to provide a 120-degree view of the combustion chamber interior. Light emitted by the spark discharge between spark electrodes and the combustion flames in the cylinder is transmitted by the optical cable to an opto-electric transducer. As a result, the ignition and combustion process which depends on the mixture formation can be easily monitored without installing transparent pistons and cylinders. This sensor can give more accurate information on mixture formation in the cylinders.

This paper reviews the technological aspects and characteristics of optical fiber gyroscopes, and discusses their automotive applications. The optical system of an all-fiber gyroscope and the fiber optic components to build it are described. An optical phase modulation scheme to improve the sensitivity and the signal processing for the modulated output are discussed. The specifications of some packaged optical fiber gyroscopes are explained. An earth's rotation detection experiment is demonstrated to show the higher performance. The potential automotive related applications of the gyroscope are forecasted. One of the off-board uses of the sensor is the vibration measurements of a vehicle. When used onboard, the optical fiber gyroscopes will improve the navigation accuracy. A navigation result utilized the sensor with a map matching algorithm is reported. The gyroscopes may also be applied to future chassis controls.

This paper proposes a new development method for highly reliable real-time embedded control systems using a CPU model-based hardware/software co-simulation. We take an approach that allows the full simulation of the virtual mechanical control system including CPU and object code level software. In this paper, Renesas SH-2A microcontroller model was developed on CoMET™ platform from VaST Systems Technology. A ETC (Electronic Throttle Control) system and engine control system were chosen to prove this concept. The ETB (Electronic Throttle Body) model on Saber® simulator from Synopsys® or engine model on MATLAB®/Simulink® simulator from MathWorks can be simulated with the SH-2A model. To help the system design, debug and evaluation, we developed an integrated behavior analyzer, which can display CPU behavior graphically during the simulation without affecting the simulation result, such as task level CPU load, interrupt statistics, software variable transition chart, and so on.

It is necessary to develop a small positive pressure control system for the closed ecology experiment facility (CEEF) to protect against over-differential pressure loading. In the present study, a numerical method was developed to calculate the quantity of state of the closed module, which is fitted with rubber buffers, for the small positive pressure control system. Experiments to examine the pressure change of the closed module were carried out at CEEF. Comparison of calculated and experimental results showed that the present dynamic simulation is suited to estimating the quantity of state of the closed module.

Emission regulations continue to be strengthened, and it is important to decrease cold start hydrocarbon concentrations in order to meet them, now and in the future. The HC concentration in engine exhaust gas can be reduced by optimizing the air-fuel ratio. However, a conventional air-fuel ratio feedback control does not operate for the first ten seconds after the engine has started because the air-fuel ratio sensor has not yet been activated. In this paper, we report on a study to optimize the air-fuel ratio using a crank angle sensor until the air-fuel ratio sensor has been activated. A difference in fuel properties was used as a typical disturbance factor. The control was applied to both a direct-injection engine (DI) and a port-injection engine (MPI). It was evaluated for two fuel types: one which evaporates easily and one which does not. The experimental results show the air-fuel ratio is optimized for both types of fuel.

Every fuel injection system for DI gasoline engines has a DC-DC converter to provide high, stabile voltage for opening the injector valve more quickly. A current control circuit for holding the valve open is also needed, as well as a large-capacity capacitor for pilot injection. Since these components occupy considerable space, an injector drive unit separate from the ECU must be used. Thus, there has been a need for a fuel injection system that can inject a small volume of fuel without requiring high voltage. To meet that need, we have developed a dual coil injector and an opening coil current control system. An investigation was also made of all the factors related to the dynamic range of the injector, including static flow rate, fuel pressure, battery voltage and harness resistance. Both efforts have led to the adoption of a battery voltage-driven fuel injector.

Plastic optical fiber has been widely used in the field of short distance optical transmission. However heat resistance of commercial plastic fiber is so low that its applications are limited. Then, a plastic fiber of thermosetting acrylate resin core has been developed. This fiber shows 80%/m retention of light transmittance at 1m after 1,000 hours at 150°C. It resists heat deformation and withstands up to 200 °C for a short time period. Tests show this fiber has desirable mechanical characteristics, along with good environmental resistance. In addition, a fiber which has a silicon resin as a core material was developed which has even better heat resistance.

The growing number of electronic components used in automobiles lately has given rise to problems concerning the increasing number, size and weight of the wiring harnesses. As one approach to resolving these problems, the authors proposed a multiplex method based on the direction of signal flow in 1988 (SAE880589). However, the need to reduce the number of wiring harnesses circuits further made it necessary to develop a more sophisticated system. This paper presents an on-board Class A local area network (LAN) system that overcomes the problems in conventional multiplexing systems through the use of a master-slave configuration, a polling selection method and a system that integrates of electronic circuits with switch modules.

This paper presents the “Virtual Failure Mode and Effects Analysis (vFMEA)” system, which is a high-fidelity electrical-failure-simulation platform, and applies it to the software verification of an electric power steering (EPS) system. The vFMEA system enables engineers to dynamically inject a drift fault into a circuit model of the electronic control unit (ECU) of an EPS system, to analyze system-level failure effects, and to verify software-implemented safety mechanisms, which consequently reduces both cost and time of development. The vFMEA system can verify test cases that cannot be verified using an actual ECU and can improve test coverage as well. It consists of a cycle-accurate microcontroller model with mass-production software implemented in binary format, analog and digital circuit models, mechanical models, and a state-triggered fault-injection mechanism.

We developed the numerical simulation tool by using OpenFOAM® and in-house simulation codes for Gasoline Direct Injection (GDI) engine in order to carry out the precise investigation of the throughout process from the internal nozzle flow to the fuel/air mixture in engines. For the piston/valve motions, a mapping approach is employed and implemented in this study. In the meantime, the spray atomization including the liquid-columnbreakup region and the secondary-breakup region are simulated by combining the different numerical approaches applied to each region. By connecting the result of liquid-column-breakup simulation to the secondary-breakup simulation, the regions which have different physical phenomena with different length scales are seamlessly jointed; i.e., the velocity and position of droplets predicted by the liquid-column-breakup simulation is used in the secondary breakup simulation so that the initial velocity and position of droplets are transferred.

The problem of high fatal accident rates due to drunk driving persists, and must be reduced. This paper reports on a prototype system mounted on a car mock-up and a prototype portable system that enables the checking of the drivers’ sobriety using a breath-alcohol sensor. The sensor unit consists of a water-vapor-sensor and three semiconductor gas sensors for ethanol, acetaldehyde, and hydrogen. One of the systems’ features is that they can detect water vapor from human-exhaled breath to prevent false detection with fake gases. Each gas concentration was calculated by applying an algorithm based on a differential evolution method. To quickly detect the water vapor in exhaled breath, we applied an AC voltage between the two electrodes of the breath-water-vapor sensor and used our alcohol-detection algorithm. The ethanol level was automatically calculated from the three gas sensors as soon as the water vapor was detected.

Predicting the vibration of a motor gearbox assembly driven by a PWM inverter in the early stages of development is demanding because the assembly is one of the dominant noise sources of electric vehicles (EVs). In this paper, we propose a simulation model that can predict the transient vibration excited by gear meshing, reaction force from the mount, and electromagnetic forces including the carrier frequency component of the inverter up to 10 kHz. By utilizing the techniques of structural model reduction and state space modeling, the proposed model can predict the vibration of assembly in the operating condition with a system level EV simulator. A verification test was conducted to compare the simulation results with the running test results of the EV.

In recent years, improvement of in-use fuel economy is required with tightening of exhaust emission regulation. We assume that one of the most effective solutions is ACC (Adaptive Cruise Control), which can control a powertrain accurately more than a driver. We have been developing a fuel saving ADAS (Advanced Driver Assistance System) application named “Sailing-ACC”. Sailing-ACC system uses sailing stop technology which stops engine fuel injection, and disengages a clutch coupling a transmission when a vehicle does not need acceleration torque. This system has a potential to greatly improve fuel efficiency. In this paper, we present a predictive powertrain state switching algorithm using external information (route information, preceding vehicle information). This algorithm calculates appropriate switching timing between a sailing stop mode and an acceleration mode to generate a “pulse-and-glide” pattern.

In-vehicle networks are generally used for computerized control and connecting information technology devices in cars. However, increasing connectivity also increases security risks. “Spoofing attacks”, in which an adversary infiltrates the controller area network (CAN) with malicious data and makes the car behave abnormally, have been reported. Therefore, countermeasures against this type of attack are needed. Modifying legacy electronic control units (ECUs) will affect development costs and reliability because in-vehicle networks have already been developed for most vehicles. Current countermeasures, such as authentication, require modification of legacy ECUs. On the other hand, anomaly detection methods may result in misdetection due to the difficulty in setting an appropriate threshold. Evaluating a reception cycle of data can be used to simply detect spoofing attacks. However, this may result in false detection due to fluctuation in the data reception cycle in the CAN.