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A flag is a global boolean variable used to achieve synchronization between various tasks of an embedded system. An application implementing flags performs actions or events based on the value of the flags. If flag variables are not implemented properly, certain synchronization related issues can arise which can lead to unexpected behavior or failure of the underlying system. In this paper, we present an automated verification technique to identify and verify flag usage patterns at an early stage of code development. We propose a two-step approach which consists of: a. identification of all potential flag variables and b. verification of flag usage patterns against predefined set of rules. The results of our experiment demonstrate that the proposed approach reduces the cost and complexity of the flag review process by almost 70%.

Increasing expectations for stability at high speed call for the improvement of cars' aerodynamic performance, in particular lift reduction. However, due to styling constraints, traditional spoilers must be avoided and replaced by other solutions like underfloor components. Flow simulation is expected to be a useful tool for lift prediction, but the conventional models used so far did not represent complex geometry details such as the engine compartment and underfloor, and accuracy was insufficient. In the present study, a full vehicle simulation model, including the engine compartment and underfloor details, was used. Other improvements were also made such as optimization of the computational grid and the setting of boundary conditions for reproducing wind tunnel experiments or actual driving, making it possible to predict lift variations due to vehicle geometry changes.

In this study, an attempt was made to apply the steering entropy method, proposed by Boer and Nakayama as a workload measurement technique, to a comparative evaluation of the workload of older and younger drivers. As the first step, driving simulator tests were conducted to examine a method of making comparisons between subjects whose driving performance differed. The same method was then used in making evaluations during driving tests conducted with an actual vehicle. Under the conditions used in this study, the results indicate that it should be possible to compare driving workloads among different subjects through the combined used of Hp and α. Hp is a quantified value of steering perturbation as an information entropy value that is calculated from a time history of steering angle data. It changes between 0 (no steering perturbation) and 1 (absolute randomness) in a theoretical sense.

This paper describes a newly developed HC-adsorption three-way catalyst and adsorption system that reduce cold-start HC emissions with high efficiency. This system is the first of its kind anywhere in the world to be implemented on production vehicles. An overview is given of the various improvements made to achieve higher cold-start HC conversion efficiency. Improvement of conversion performance was accomplished by (1) increasing the thermal stability of the HC adsorbent, (2) improving desorbed HC conversion efficiency and durability and (3) optimizing the geometric surface area (GSA) of the substrate. Concretely, the thermal stability of the adsorbent was improved by enhancing the high-temperature durability of zeolite. Improvement of desorbed HC conversion efficiency was accomplished by improving the OSC material so as to match the temperature rise characteristic and usage temperature of the catalyst.

Digital signal processors (DSPs) are being used widely for sound field reproduction. However, it is difficult to apply a DSP to a car audio system because of the complicated acoustic characteristics of the passenger compartment. The authors have developed a new car audio system which employs special DSP software and a new speaker layout to provide excellent presence. The DSP has five output channels to generate stereophonic reflection from the front and rear speakers. The DSP software is programmed for each individual car model. A center speaker and A-pillar tweeters are used to produce a natural sound field in front through effective utilization of reflection from the windshield. This system is featured in 1992 Nissan models.

An electric vehicle (EV) has less powertrain energy loss than an internal combustion engine vehicle (ICE), so its aerodynamic accounts have a larger portion of drag contribution of the total energy loss. This means that EV aerodynamic performance has a larger impact on the all-electric range (AER). Therefore, the target set for the aerodynamics development for a new EV hatchback was to improving AER for the customer’s benefit. To achieve lower aerodynamic drag than the previous model’s good aerodynamic performance, an ideal airflow wake structure was initially defined for the new EV hatchback that has a flat underbody with no exhaust system. Several important parameters were specified and proper numerical values for the ideal airflow were defined for them. As a result, the new EV hatchback achieves a 4% reduction in drag coefficient (CD) from the previous model.

This paper describes a control method to improve straight-line stability without sacrificing natural steering feel, utilizing a newly developed steering system controlling the steering force and the wheel angle independently. It cancels drifting by a road cant and suppresses the yaw angle induced by road surface irregularities or a side wind. Therefore drivers can keep the car straight with such a little steering input adjustment, thus reducing the driver's workload greatly. In this control method, a camera mounted behind the windshield recognizes the forward lane and calculate the discrepancy between the vehicle direction and the driving lane. This method has been applied to the test car, and the reduction of the driver's workload was confirmed. This paper presents an outline of the method and describes its advantages.

Over the past several decades, vehicle dynamics have been treated mainly on the basis of linear theories. An actual vehicle, however, also shows nonlinear properties such as roll behavior induced by movement of the roll axis. The purpose of this study was to investigate the vehicle roll dynamics in the nonlinear range. Suspensions were divided into two categories and computer-aided engineering (CAE) was used to conduct analyses of complicated kinematics. The results obtained provided theoretical support for designing the Multi-Link Beam Rear Suspension, a new type of suspension for front-wheel-drive cars.

Three Japanese automobile manufacturers-Mitsubishi Motors Corp., Nissan Motor Co., Ltd., and Toyo Kogyo Co., Ltd.-have been making efforts over the past three years to design and develop effective thermal reactor-exhaust gas recirculation and catalytic converter systems suitable for small engines. The work is being done by members participating in the IIEC (Inter-Industry Emission Control) Program, and the exhaust emission levels of the concept vehicles developed by these companies have met the goal established by the IIEC Program at low mileage. Each system, however, has a characteristic relationship between exhaust emission level and loss of fuel economy. Much investigation is required, particularly with respect to durability, before any system that will fully satisfy all service requirements can be completed. This paper reports the progress of research and development of the individual concept vehicles.

This paper describes the plastic body panels developed for the Nissan Be-1 which was released and put on sale in Japan in January 1987. The panels include four body parts: left and right front fenders, front apron and rear apron. They are made of a thermoplastic resin and are produced by injection molding. The top paint coat can be sprayed on all four panels simultaneously with other steel body panels. The panels provide a high-quality appearance that is in no way inferior to the paint quality of steel panels. This is true during initial use as well as over long periods of time. Besides providing weight reductions, they also deliver improved resistance to impacts. CAE process was applied to develop these panels and proved to be quite effective.

THIS PAPER presents an advanced heads-up display which has been newly developed for use in 88 Nissan Silvia model. The HUD consists of a projector with a newly developed high brightness VFD and light-selective film used as a combiner which is coated on the windshield. This combination provides good display legibility even under bright sunlight. The display shows the vehicle speed in a three-digit reading at distance of more than one meter from the driver's eyes. The windshield-coated combiner conforms to U.S. safety standards concerning light transmittance, abrasion and other performance requirements. Experimental data are also presented which substantiate the HUD's high legibility and confirm its effect in enhancing the driver's attention toward the road ahead

Although automotive electronics was initially applied as a substitute for mechanical parts, this technology has the potential to achieve effective combinations of mechanical functions. A case in point is the successful resolution of fuel consumption and exhaust emission problems by effectively integrating engine control and catalyst technologies. LSI technology has also been incorporated into automotive electronics and established as a fundamental engine control tool. Thanks to LSI technology, particularly the use of microprocessor techniques, conventional machine design problems have been transformed into logical design ones. In the next stage of application, automotive electronics is expected to provide further benefits including a more comfortable ride, an improved human-machine system interface, and an advanced communications system between vehicles and other telecommunications stations.

This paper deals with the development of plastics recycling technology, which is one key to resolving environmental and natural resource problems and encouraging recycling activities. Bumpers are among the heaviest plastic auto parts, so the technology for recycling bumpers is strongly required. Paint remaining on bumpers causes the strength of the recycled material to decline and degrades its surface quality. Therefore, unless the paint is removed, it is impossible to use recycled material to manufacture new bumpers. This hampers recycling efforts and results in low-value recycled material. Consequently, it is essential to develop a simple paint removing without chemical substances for practical plastics recycling at low cost. Two topics are discussed in this paper. The first concerns the mechanism of paint removal and the development of a technique for utilizing that mechanism.

The new Murano was developed with special emphasis on improving aerodynamics in order to achieve fuel economy superior to that of competitor models. This paper describes the measures developed to attain a drag coefficient (CD) that is overwhelmingly lower than that of other similar models. Special attention was paid to optimizing the rear end shape so as to minimize rear end drag, which contributes markedly to the CD of sport utility vehicles (SUVs). A lower grille shutter was adopted from the early stage of the development process. When open, the shutter allows sufficient inward airflow to ensure satisfactory engine cooling; when closed, the blocked airflow is actively directed upward over the body. The final rear end shape was tuned so as to obtain the maximum aerodynamic benefit from this airflow. In addition, a large front spoiler was adopted to suppress airflow toward the underbody as much as possible.

It is considered that door mirror drag is composed of not only profile drag but also interference drag that is generated by the mixing of airflow streamlines between door mirrors and vehicle body. However, the generation mechanism of interference drag remained unexplained, so elucidating mechanism for countermeasures reducing drag have been needed. In this study, the prediction formulas for door mirror drag expressed by functions in relation to velocities around the vehicle body were derived and verified by wind tunnel test. The predicted values calculated by formulas were compared with the measured values and an excellent agreement was found. In summary, new prediction formulas made it possible to examine low drag mirror including profile and interference drag.

This paper explains the specific measures taken to develop the body and underfloor of the newly developed Electric Vehicle for the purpose of reducing drag. Additionally, the headlamps and fenders were designed with innovative shapes to reduce wind noise that occurs near the outside mirrors. As a result of utilizing the aerodynamic advantages of an electric vehicle to maximum effect, The newly developed Electric Vehicle achieves a class-leading drag coefficient and interior quietness.