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Development of truck and bus aerodynamics using computational fluid dynamics
188
Abstracts /JSAE Review 18 (1997) 185-209
Wind noise emitted from around the A-pillar of a production vehicle was predicted. Flow fields were calculated by solving an unsteady three-dimensional Navier-Stokes equation using a third-order upwind finite difference method with an overlaid grid system. The sources of aeroacoustic noise on the vehicle body surface were then calculated on the basis of the distribution of pressure fluctuation. By observing the distribution of the aeroacoustic noise sources and oil flow pattern on the surface, it was found that several peaks of frequency exist on the A-pillar and broad band noise sources are observed in a closed separation region. 9636862 T r a n s i e n t Aerodynamic Simulation in Crosswind. Kenji Okumura, Toshihiko Kuriyama (Dathatsu Motor Co., Ltd.) In this paper, transient aerodynamic simulation by using a sliding mesh of discontinuous interface and the Arbitrary Lagrangian-Eulerian method is presented. This method uses the k-e turbulence model and the third-order upwind scheme, which is introduced to the convective term of Navier-Stokes Equation to improve flow field and pressure distribution. Computed Yaw characteristics in crosswind are in good agreement with the experiments. Furthermore we have simulated the effect of an Active Spoiler on a One-Box automobile in crosswind.
9636871 Aerodynamic Simulations by Using Discontinuous Interface Grid and Solution Adaptive Grid Method Katsuya Uchida, Kenji Okumura, Toshihiko Kuriyama (Daihatsu Motor Co., Ltd) Aerodynamic simulations of an automobile with the air-flow type spoiler using a discontinuous interface grid method and flow simulation around the rear view door mirror using a solution adaptive grid method are presented in this paper. Consequently, it has become possible to capture the detailed phenomena around these parts, such as the spoiler and rear view door mirror. Also the development term is reduced by using these new methods. 9636880 Development of Rear Spoiler for Hatchback Vehicles using
Concurrent CFD Method - - Design of Central Cross Sectional Shape of Spoiler using CFD Method Kiyoshi Yamane, Nobutoshi Hase, Sadao Fujita, Ryouji Isomura, Ikuya Takeda (Aisin Seiki Co., Ltd.), Keiji Sumitani, Toshiyuki Murayama (Toyota Motor Corp.) Airflow effect is one of the important functions demanded of a rear spoiler. It helps prevent mud or dust from swirling up behind the running vehicle, or, in the case of driving in rain or snow, helps prevent rain or snow from adhering to the rear window. We often decide on the shape of a spoiler in a relatively short time, focusing primarily on its appearance. Therefore, we established a design method using recently developed computational fluid dynamics to determine the central cross sectional shape of spoiler that realizes a desired airflow effect and verified its effectiveness through testing. 9636899 Development of Shape-Topology Optimization Method for Air Duct Layout (Part 1: Survey on Two-Dimensional Design Problems) Tohru Komoriya (Subaru Research Center Co., Ltd.) It is a difficult task for design engineers to decide the layout of ducts with less pressure loss. To solve this problem, we have developed a new topology optimization techique for the air duct layout. This method gives the optimum duct topology in the condition of same duct volume. After investigations of this method for a two-dimensional return bend where inlet and outlet of air flow are on the same side wall, we have obtained satisfactory results. Applying this to other layout problems, it was shown that this new method is effective for the two-dimensional design of an air duct layout. 9639076 Development of Truck and Bus Aerodynamics using Computational Fluid Dynamics Toshio Takeuchi, Itsuhei Kohri (Mitsubishi Motors Corp.) This paper describes a prediction method of aerodynamic drag and engine cooling performance for trucks and buses using CFD. In particular, to obtain the accuracy of wake flow behind the body, which is a
dominant component of the total drag, we developed an adequate method by comparing the experiment with calculation. Furthermore we show a practical method for engine cooling air flow rate with regard to radiator and cooling fan characteristics. 9636907 The Influence of Automatic Vehicle Control Algorithm on Traffic Flow Tetsushi Kokubo, Ken-ichi Yoshimoto (The University of Tokyo) The AVCS (Automatic Vehicle Control Systems) can be used not only for drivers support and reduction of traffic accidents, but also for smoothing the traffic flow. In this paper, we investigate the influence of AVCS on traffic flow - - especially traffic volume - - from the viewpoint of automatic control theory. We also show the simulated results using the proposed scheme. 9636916 Analysis of the Benefits of Freight Consolidation in Auto Parts Delivery Tom Takagi, Koji Sato, Kazuyoshi Okada (Nissan Motor Co., Ltd.) The paper proposes a consolidated freight transportation system. Under this system, auto parts manufacturers would establish an integrated logistics center for their area and then ship products there, where they would be loaded on large trailers in mixed loads for direct shipment to vehicle assembly plants. This system is intended to replace the existing system, whereby manufacturers transport parts to assembly plants from nearby depots. An overview of the system is presented, along with an explanation of how potential environmental quality improvements were calculated. 9636925 The Development of a Simulation Model of the Driver's Behavior when Encountering a Parked Car Yasuhisa Kishi, Shinichi Katsuki, Masaaki Tanignchi, Satoshi Okamoto (Nissan Motor Co., Ltd.) Cars that are parked on sweets interfere with traffic flow, with significant influence. Although various methods axe available to solve this problem, as yet there axe few ways to estimate the effects of implementing such methods. Thus, quantitatively analyzing this situation is difficult. However, to analyze the situation as accurately as possible, we selected a series of actions that a driver would perform when driving on a straight street and encountering a parked car. From these actions, we were able to determine the behavior patterns of the drivers and the main factors that influence traffic flow. We then made a computer simulation model based on the driver's situation and reactions, and evaluated the reappearance of evading behavior.
9636943 Feasibility Study of Superconducting Applications for New Generation Vehicle - The Study of New Power Train for HEV Osamu Komeda, Yoshitaka Kanbe, Tamio Shinozawa (Toyota Motor Corp.) In order to solve the future problems of the environment and energy conservation, an advanced vehicle concept using a superconducting magnet was considered. As superconducting magnet stores magnetic energy and prepares the magnetic field for the traction motor. A superconducting magnet with a motor using Nb-Ti wire was produced and its performance was investigated. The most important problem for this concept is hoop stress. Our experiments and analysis indicated that a superconducting thick film may reform magnetic force and reduce the tension in the wire. If this can be realized, the superconducting magnet will be an important component of vehicles in the future.
9636952 Brake Force Distribution Control System using Hydraulic Brake Actuator Takayuki Ito, Yoshiyuki Yasui, Kenji Tozu, Noriaki Hattori (Aisin Seiki Co., Ltd.), Norio Yamazaki (Aisin Newhard Co., Ltd.) For active safety, several brake control systems, which improve ABS performance or extend ABS function, have been developed and put to practical use. In this paper, we describe brake force distribution control (BDC), which is consistent with vehicle deceleration and stability. A
Abstracts /JSAE Review 18 (1997) 185-209
Wind noise emitted from around the A-pillar of a production vehicle was predicted. Flow fields were calculated by solving an unsteady three-dimensional Navier-Stokes equation using a third-order upwind finite difference method with an overlaid grid system. The sources of aeroacoustic noise on the vehicle body surface were then calculated on the basis of the distribution of pressure fluctuation. By observing the distribution of the aeroacoustic noise sources and oil flow pattern on the surface, it was found that several peaks of frequency exist on the A-pillar and broad band noise sources are observed in a closed separation region. 9636862 T r a n s i e n t Aerodynamic Simulation in Crosswind. Kenji Okumura, Toshihiko Kuriyama (Dathatsu Motor Co., Ltd.) In this paper, transient aerodynamic simulation by using a sliding mesh of discontinuous interface and the Arbitrary Lagrangian-Eulerian method is presented. This method uses the k-e turbulence model and the third-order upwind scheme, which is introduced to the convective term of Navier-Stokes Equation to improve flow field and pressure distribution. Computed Yaw characteristics in crosswind are in good agreement with the experiments. Furthermore we have simulated the effect of an Active Spoiler on a One-Box automobile in crosswind.
9636871 Aerodynamic Simulations by Using Discontinuous Interface Grid and Solution Adaptive Grid Method Katsuya Uchida, Kenji Okumura, Toshihiko Kuriyama (Daihatsu Motor Co., Ltd) Aerodynamic simulations of an automobile with the air-flow type spoiler using a discontinuous interface grid method and flow simulation around the rear view door mirror using a solution adaptive grid method are presented in this paper. Consequently, it has become possible to capture the detailed phenomena around these parts, such as the spoiler and rear view door mirror. Also the development term is reduced by using these new methods. 9636880 Development of Rear Spoiler for Hatchback Vehicles using
Concurrent CFD Method - - Design of Central Cross Sectional Shape of Spoiler using CFD Method Kiyoshi Yamane, Nobutoshi Hase, Sadao Fujita, Ryouji Isomura, Ikuya Takeda (Aisin Seiki Co., Ltd.), Keiji Sumitani, Toshiyuki Murayama (Toyota Motor Corp.) Airflow effect is one of the important functions demanded of a rear spoiler. It helps prevent mud or dust from swirling up behind the running vehicle, or, in the case of driving in rain or snow, helps prevent rain or snow from adhering to the rear window. We often decide on the shape of a spoiler in a relatively short time, focusing primarily on its appearance. Therefore, we established a design method using recently developed computational fluid dynamics to determine the central cross sectional shape of spoiler that realizes a desired airflow effect and verified its effectiveness through testing. 9636899 Development of Shape-Topology Optimization Method for Air Duct Layout (Part 1: Survey on Two-Dimensional Design Problems) Tohru Komoriya (Subaru Research Center Co., Ltd.) It is a difficult task for design engineers to decide the layout of ducts with less pressure loss. To solve this problem, we have developed a new topology optimization techique for the air duct layout. This method gives the optimum duct topology in the condition of same duct volume. After investigations of this method for a two-dimensional return bend where inlet and outlet of air flow are on the same side wall, we have obtained satisfactory results. Applying this to other layout problems, it was shown that this new method is effective for the two-dimensional design of an air duct layout. 9639076 Development of Truck and Bus Aerodynamics using Computational Fluid Dynamics Toshio Takeuchi, Itsuhei Kohri (Mitsubishi Motors Corp.) This paper describes a prediction method of aerodynamic drag and engine cooling performance for trucks and buses using CFD. In particular, to obtain the accuracy of wake flow behind the body, which is a
dominant component of the total drag, we developed an adequate method by comparing the experiment with calculation. Furthermore we show a practical method for engine cooling air flow rate with regard to radiator and cooling fan characteristics. 9636907 The Influence of Automatic Vehicle Control Algorithm on Traffic Flow Tetsushi Kokubo, Ken-ichi Yoshimoto (The University of Tokyo) The AVCS (Automatic Vehicle Control Systems) can be used not only for drivers support and reduction of traffic accidents, but also for smoothing the traffic flow. In this paper, we investigate the influence of AVCS on traffic flow - - especially traffic volume - - from the viewpoint of automatic control theory. We also show the simulated results using the proposed scheme. 9636916 Analysis of the Benefits of Freight Consolidation in Auto Parts Delivery Tom Takagi, Koji Sato, Kazuyoshi Okada (Nissan Motor Co., Ltd.) The paper proposes a consolidated freight transportation system. Under this system, auto parts manufacturers would establish an integrated logistics center for their area and then ship products there, where they would be loaded on large trailers in mixed loads for direct shipment to vehicle assembly plants. This system is intended to replace the existing system, whereby manufacturers transport parts to assembly plants from nearby depots. An overview of the system is presented, along with an explanation of how potential environmental quality improvements were calculated. 9636925 The Development of a Simulation Model of the Driver's Behavior when Encountering a Parked Car Yasuhisa Kishi, Shinichi Katsuki, Masaaki Tanignchi, Satoshi Okamoto (Nissan Motor Co., Ltd.) Cars that are parked on sweets interfere with traffic flow, with significant influence. Although various methods axe available to solve this problem, as yet there axe few ways to estimate the effects of implementing such methods. Thus, quantitatively analyzing this situation is difficult. However, to analyze the situation as accurately as possible, we selected a series of actions that a driver would perform when driving on a straight street and encountering a parked car. From these actions, we were able to determine the behavior patterns of the drivers and the main factors that influence traffic flow. We then made a computer simulation model based on the driver's situation and reactions, and evaluated the reappearance of evading behavior.
9636943 Feasibility Study of Superconducting Applications for New Generation Vehicle - The Study of New Power Train for HEV Osamu Komeda, Yoshitaka Kanbe, Tamio Shinozawa (Toyota Motor Corp.) In order to solve the future problems of the environment and energy conservation, an advanced vehicle concept using a superconducting magnet was considered. As superconducting magnet stores magnetic energy and prepares the magnetic field for the traction motor. A superconducting magnet with a motor using Nb-Ti wire was produced and its performance was investigated. The most important problem for this concept is hoop stress. Our experiments and analysis indicated that a superconducting thick film may reform magnetic force and reduce the tension in the wire. If this can be realized, the superconducting magnet will be an important component of vehicles in the future.
9636952 Brake Force Distribution Control System using Hydraulic Brake Actuator Takayuki Ito, Yoshiyuki Yasui, Kenji Tozu, Noriaki Hattori (Aisin Seiki Co., Ltd.), Norio Yamazaki (Aisin Newhard Co., Ltd.) For active safety, several brake control systems, which improve ABS performance or extend ABS function, have been developed and put to practical use. In this paper, we describe brake force distribution control (BDC), which is consistent with vehicle deceleration and stability. A