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Powertrain development requires an efficient development process with no rework and model-based development (MBD). In addition, to performance design that achieves low CO2 emissions is also required. Furthermore, it also demands fuel economy performance considering real-world usage conditions, and in North America, the EPA (U.S. Environmental Protection Agency) 5-cycle, which evaluates performance in a combination of various environments, is applied. This evaluation mode necessitates predicting performance while considering engine heat flow. Particularly, simulation technology that considers behavior based on engine temperature for Hybrid Electric Vehicle (HEV) is necessary. Additionally, in the development trend of vehicle aerodynamic improvement, variable devices like Active Grille Shutter (AGS) are utilized to contribute to reducing CO2 emissions.

In this paper, a newly developed Active Noise Control (ANC) system is introduced, that effectively reduces road noise, which becomes a major issue with electrified vehicles, and that enhances vehicle interior sound levels matching seamless acceleration by electric drive. Conventionally, reducing road noise using ANC requires numerous sensors and speakers, as well as a processor with high computing power. Therefore, the increase in system cost and the complexity of the system are obstacles to its spread. To overcome these issues, this system is developed based on four concepts. The first is a modular system configuration with unified interface to apply to various vehicle types and grades. The second is the integration and optimal placement of noise source reference sensors to achieve both reduction in number of parts and noise reduction performance.

Today’s progress in electronic technologies is advancing the process of making vehicles more intelligent, and this is making driving safer and more comfortable. In recent years, numerous vehicles equipped with high-level Advance Driving Assist System (ADAS) have been put on the market. High-level ADAS can detect impending lane deviation, and control the vehicle so that the driver does not deviate from the lane. Lane departure prevention systems are able to detect imminent departure from the road, allowing the driver to apply control to prevent lane departure. These systems possess enormous potential to reduce the number of accidents resulting from road departure, but their effectiveness is highly reliant on their level of acceptance by drivers.

Gaskets made of joint sheet are widely used for mating surfaces in engines and transmissions. Before the regulation was issued for restrictions of asbestos usage as a hazardous substance, Honda had already developed non-asbestos joint sheets using aramid fibers substituting for asbestos and started applying them to the products sold worldwide. However, aramid fiber is significantly expensive but, on the other hand, the amount of aramid fiber mixed in a joint sheet will largely influence the sealing performance. Thus, when aramid fiber is applied, cost increase becomes a concern. With this background, a gasket material was designed for reducing the cost without sacrificing the required reliability as a joint sheet assuming the actual applications. The cost was reduced mainly by reducing the amount of aramid fibers used.

In motorcycles, the mass difference between a vehicle and a rider is small and motions of a rider impose a great influence on the vehicle behaviors as a consequence. Therefore, dynamic properties of motorcycles should be evaluated not merely dealing with a vehicle but considering with a man-machine system. In the studies of a simulation for vehicle dynamics, various types of rider models have been proposed and it has already been reported that rider motions have a significant influence on the dynamic properties. However, the mechanism of the interaction between a rider and a vehicle has not been clarified yet. In our study, we focused on weave motion and constructed a full vehicle simulation model that can reflect the influences of the movements of the rider’s upper body and lower body. To construct the rider model, we first measured the vibrational characteristics of a human body using a vibration test bench.

Lane departure prevention systems are able to detect imminent departure from the road, allowing the driver to apply control to prevent lane departure. These systems possess enormous potential to reduce the number of accidents resulting from road departure, but their effectiveness is highly reliant on their level of acceptance by drivers. The effectiveness of the systems will depend on when they are providing driving assistance, what level of laxness in terms of maintaining contact with the steering wheel is allowed on the part of the driver, and what level of assistance the system provides. This paper will discuss research on the minimum necessary contact and contact strength with the steering wheel on the part of the driver when a lane departure prevention system is in operation.

Along with the suspension improvement in these two decades, it is well known that the suspension friction force became one of major parameters to affect ride comfort performance. However, it was difficult to carry out quantitative prediction on ride comfort improvement against friction force change with high correlation. It was difficult to analyze correlation between actual vehicle performance and simulation since there were difficulties in controlling damping force and friction individually. On the other hand, magneto-rheological shock absorber (MR Shock) has had several applications and widely spread to passenger vehicles. The large variation and high response of damping force especially in slow piston speed region contributes to achieve an excellent vehicle dynamics performance. However, MR Shock shows the high friction characteristics, due to the unique sliding regime of internal parts. It is said that this high friction characteristic is causing obstacles in ride-comfort.

This research sought to develop a dynamic charging system, achieving an unlimited EV cruising range by charging the EV at high power during cruising. This system would help make it possible to finish battery charging in a short time by contact with the EV while cruising and enable drivers to freely cruise their intended routes after charging. A simulation of dynamic charging conditions was conducted for ordinary autonomous cruising (i.e., ordinary EV cruising) when dynamically charging at a high power of 450-kW (DC 750 V, 600 A). This report discusses the study results of a method of building the infrastructure, as well as looking at the cruise test results and future outlook. In particular, the research clarified the conditions for achieving an unlimited vehicle cruising range with a 450-kW dynamic charging system. It also demonstrated that this system would allow battery capacities to be greatly reduced and make it possible to secure the battery supply volume and resources.

Vehicles are required durability in various environments all over the world. Especially water resistance on flooded roads is one of the important issues. To solve this kind of problem, a CFD technology was established in order to predict the water resistance performance of the vehicle at the early development stage. By comparison with vehicle tests on flooded roads, it is clarified the following key factors are required for accurate prediction; the vehicle velocity change, the vehicle height change and the air intake flow rate. Moreover, these three key factors should be appropriately determined from vehicle and engine specification to predict water intrusion for flooded roads at the early stage of development. In this paper, a methodology which determines appropriate analysis conditions mentioned above for flooding simulation from vehicle and engine specification is described. The methodology enables us to determine whether the vehicle provides sufficient waterproofness.

To comply with the environmental demands for CO2 reduction without compromising driving performance, a new 1.0 liter I3 turbocharged gasoline direct injection engine has been developed. This engine is the smallest product in the new Honda VTEC TURBO engine series (1), and it is intended to be used in small to medium-sized passenger car category vehicles, enhancing both fuel economy through downsizing, state-of-the-art friction reduction technologies such as electrically controlled variable displacement oil pump and timing belt in oil system, and also driving performance through turbocharging with an electrically controlled waste gate. This developed engine has many features in common with other VTEC TURBO engines such as the 1.5 liter I4 turbocharged engine (2) (3), which has been introduced already into the market.

A second-generation power control unit (PCU) for a two-motor hybrid system is proposed. An optimally designed power module, which is a key component of the PCU, is applied to increase heat-resistant temperature, while the basic structure of the first generation is retained and the power semiconductor chip is directly cooled from the single side. In addition to the optimum design, by decreasing the power loss as well as increasing the heat-resistant temperature of the power semiconductors (IGBT: Insulated Gate Bipolar Transistor and FWD: Free Wheeling Diode), the proposed PCU has attained 25% higher power density and 23% smaller size compared to first-generation units, maintaining PCU efficiency (fuel economy). To achieve a high yield rate in the power module assembly process, a new screening technology is adopted at the initial stage of power module manufacturing.

Conventionally, it has not been possible to evaluate current and temperature in power control units (PCU) for hybrid electric vehicles (HEV) during vehicle operation without using an actual permanent magnet synchronous motor (PMSM). The research discussed in this paper developed a motor emulator to take the place of an actual motor, making it possible to conduct tests for the evaluation of current and temperature in PCU during vehicle operation without the need to use a motor. The motor emulator is provided with a hardware-in-the-loop (HIL) simulator that calculates motor models at high speed using a field programmable gate array (FPGA). The developed system models the motor in detail via the HIL simulator, while a 3-phase current generator accurately reproduces the transient current in the PCU during vehicle operation.

A method applicable in the design stage to predict fatigue strength of a motorcycle exhaust system was developed. In this prediction method, a vibrating stress, thermal stresses, stresses resulting from the assembling of the exhaust system components and a deterioration of fatigue strength of materials originated from high temperature were simultaneously taken into account. For the prediction of the vibrating stress, flexible multibody dynamics was applied to get modeling accuracy for vibration characteristics of the entire motorcycle and the exciting force delivered from engine vibrations. The thermal conduction analysis and the thermal deformation analysis based on finite element method (FEM) were applied for the prediction of thermal stresses in the exhaust system components. The temperature distribution on the surfaces of the exhaust system components is required for calculations of the thermal stresses.

We had developed Electric Servo Brake System, which can control brake pressure accurately with a DC motor according to brake pedal force. Therefore, the system attains quality brake feeling while reflecting intentions of a driver. By the way, “Build-up” is characteristics that brake effectiveness increases in accordance with the deceleration of the vehicle, which is recognized as brake feeling with a sense of relief as not to elongate an expected braking distance at a downhill road due to large-capacity brake pad such as sports car and large vehicles. Then, we have applied the optical characteristic control to every car with Electric Servo Brake System by means of brake pressure control but not brake pad. Hereby, we confirmed that the control gives a driver the sense of relief and the reduction of pedal load on the further stepping-on of the pedal. In this paper, we describe the development of brake feel based on the control overview.

1. On page 111, the authors have described a method to assess driver distraction. In this method, participants maintained a white square size on a forward display by using a game gas pedal of like in car-following situation. The size of the white square is determined by calculating the distance to a virtual lead vehicle. The formulas to correct are used to explain variation of acceleration of the virtual lead vehicle. The authors inadvertently incorporated old formulas they had used previously. In the experiments discussed in the article, the corrected formulas were used. Therefore, there is no change in the results. The following from the article:

When a vehicle is in motion, noise is generated in the cabin that is composed of noise in multiple narrow-frequency bands and caused by input from the road surface. This type of noise is termed low-frequency-band road noise, and its reduction is sought in order to increase occupant comfort. The research discussed in this paper used feedback control technology as the basis for the development of an active noise control technology able to simultaneously reduce noise in multiple narrow-frequency bands. Methods of connecting multiple single-frequency adaptive notch filters, a type of adaptive filter, were investigated. Based on the results, a method of connecting multiple filters that would mitigate mutual interference caused by different controller transmission characteristics was proposed.

The mounting of lithium-ion batteries (LIB) in hybrid electric vehicles (HEV) calls for the configuration of highly robust control systems. When mounting LIBs in the vehicle, it is important to accurately ascertain and precisely control the state of the battery. In order to achieve high durability, it is important to configure highly reliable systems capable of dependably preventing overcharging as well as to have control technology based on software that can contribute to extended battery life. The system configuration applies an overcharge prevention system that uses voltage detection with an emphasis on reliability. Furthermore, a method for varying the range of state of charge (SOC) control in the vehicle according to the battery state is implemented to assure durability. In order to achieve this, battery-state detection technology was developed for the purpose of correctly detecting and judging the battery state.

We have developed a bench test method to assess driver distraction caused by the load of using infotainment systems. In a previous study, we found that this method can be used to assess the task loads of both visual-manual tasks and auditory-vocal tasks. The task loads are assessed using the performances of both pedal tracking task (PT) and detection response task (DRT) while performing secondary tasks. We can perform this method using simple equipment such as game pedals and a PC. The aim of this study is to verify the reproducibility of the PT-DRT. Experiments were conducted in three test environments in which test regions, experimenters and participants differed from each other in the US, and the test procedures were almost the same. We set two types of visual-manual tasks and two types of auditory-vocal tasks as secondary tasks and set two difficulties for each task type to vary the level of task load.

Recently, automotive emission regulations are being further tightened, such as the Tier III/LEV III in the U.S. As a result, reducing cost of after-treatment systems to meet these strict regulations has become an urgent issue, and then the demand for high-precision air-fuel ratio (A/F) control which can achieve this cost reduction is high [1]. On the other hand, in order to meet rapidly changing market needs, it is becoming difficult to keep enough development periods that enable sufficient calibration by trial-and-error, such as feedback-gain calibration. This leads to an increase in three-way catalytic converter costs in some cases. For these reasons, it is necessary to construct control system that can make full use of hardware capabilities, can shorten development periods regardless of the skill level of engineers.

According to the North American National Automotive Sampling System Crashworthiness Data System (NASS/CDS), approximately one-half of all accidents during driving are of the secondary collision pattern in which the collision event involves the occurrence of secondary collision. Accidents involving impact to a stopped vehicle (chain-reaction collisions) have increased to approximately 3% of all accidents in North America, and although the rate of serious injury is low, cases have been reported of accidents in which cervical sprain occurs as an after-effect[1]. In order to mitigate these circumstances, research has been conducted on systems of automatic braking for collisions. These systems apply brakes automatically when a first collision has been detected in order to avoid or lessen a second collision. Research on automatic collision braking systems, however, has not examined the multiple collisions parked [1, 2].