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This paper describes a simple engine model at idling and it applies particularly to idle speed control. Through linearization in the neighborhood of the nominal operating points (650 rpm), the engine is expressed as a reduced-order constant coefficient state variable (2 state) model. It was produced through the system order-reduction method. The strategy for controlling idle speed uses the Linear Quadratic and Integral (LQI) optimal control theory. The tracking controller was designed using a state variable engine model, and the performance index was minimized. Since state variables are artificially introduced, they are not directly accessible. Therefore, they must be estimated in accordance with a stored dynamic model (i.e. observer), in which the engine dynamic behavior is estimated on the basis of a state variable model which represents the engine's internal states, in determining controlling values.

Curbing emissions of carbon dioxide (CO₂), which is believed by many scientists to be a major contributor to global warming, is one of the top priority issues that must be addressed by automobile manufacturers. Automakers have set their own strategies to improve fuel economy and to reduce CO₂ emissions. Some of them include integrated approaches, focusing on not only improvement of vehicle technology, but also human factors (eco-driving support for drivers) and social and transportation factors (traffic management by intelligent transportation systems [ITS]). Among them, electric vehicles (EVs) will be a key contributor to attaining the challenging goal of CO₂ reduction. Mass deployment of EVs is required to achieve a zero-emission society. To accomplish that, new advanced technologies, new business schemes, and new partnerships are required.

After the turn of the century, growing social attention has been paid to environmental concerns, especially the reduction of greenhouse gas emissions and it comes down to a personal daily life concern which will affect the purchasing decision of vehicles in the future. Among all the sources of greenhouse gas emissions, the transportation industry is the primary target of reduction and almost every automotive company pours unprecedented amounts of money to reengineer the vehicle technologies for better fuel efficiency and reduced CO2 emission. Besides those efforts paid for sheer improvements of genuine vehicle technologies, NISSAN testified that “connectivity” with outside servers contributed a lot to reduce fuel consumption, thus the less emission of GHG, with two major factors; 1. detouring the traffic congestions with the support of probe-based real-time traffic information and 2. providing Eco-driving advices for the better driving behavior to prompt the better usage of energy.

An electric vehicle (EV) is promising as clean energy powered vehicle, due to increased interest in fuel economy and environment in recent years. However, it requires to meet unique safety performance such as electric safety. Nissan has developed a new electric vehicle which achieves electric safety in addition to maintaining enough cruising distance and cabin space. This was achieved by I he development of an all-new platform for electric vehicles. The electric safety was enhanced by the protection of high-voltage components based on consideration of component layout and body structure, high-voltage shutdown by impact sensing system and prevention of short circuit by fuse in the battery. As an example of the protection of high-voltage components, the battery which locates under the floor was protected by elaborative packaging and multi-layer protection structure.

At Nissan we have developed a new parallel hybrid system for rear-wheel-drive hybrid vehicles. As the main components of the hybrid system, both the motor and the inverter have been developed and are manufactured in house to attain high power density for providing responsive acceleration, a quiet EV drive mode and improved fuel economy. Because the motor is located between the engine and the transmission, it had to be shortened to be within the length allowed for the powertrain. Therefore, new technologies have been developed such as high-density, square-shaped windings and an optimized magnetic circuit specially designed for concentrated winding motors. The inverter is sized to a 12V battery, which it replaces in the engine compartment. Despite its compact size, the inverter must have rather large current capacity to drive a high-power motor. Heat management is critical to the design of a small but high-power inverter.

The shape and topology optimization method using a homogenization method is a powerful design tool because it can treat topological changes of a design domain. This method was originally developed in 1988 [1] and have been studied by many researchers. However, their scope of application in real vehicle design works has been limited where a design domain and boundary conditions are very complicated. The authors have developed a powerful optimization system by adopting a general purpose finite element analysis code. A method for treating vibration problems is also discussed. A new objective function corresponding to a multi-eigenvalue optimization problem is suggested. An improved optimization algorithm is then applied to solve the problem. Applications of the optimization system to design the body and the parts of a solar car are presented.

The expanded application of automotive electronics in recent years has increased the number of control switches, thus necessitating the optimization of their layout around the driver and improvement in operability. As an effective means in improving operability, switches mounted on the steering wheel have been developed, placing controls closer to drivers for easier access while driving. However, since the switches rotate along with the steering wheel, recognition and operation of those switches left a few things to be desired. Recently we developed a "steering wheel with a non-rotating center switch pad" where the pad section with the switches are kept stationary. In this paper we describe the general outline of this development.

This paper presents a lightweight, high-performance Lithium-ion Battery System developed jointly by Nissan Motor Co. and Sony Corp. for electric vehicle (EV) use. Electric vehicles are generally powered by a battery pack consisting of numerous cells connected in a series. Management techniques to elicit the maximum performance of the battery pack are needed, including a function for monitoring individual cells to prevent them from over-discharging. Because of high cell voltage, lithium-ion batteries enable the number of cells in a battery pack to be greatly reduced compared with other types of battery systems. They also allow accurate detection of the battery State of Charge (SOC) based on the battery voltage. These characteristics are conducive to the application of battery pack management technology. These concepts provided the basis for the development of a Lithium-ion Battery System for EV application.

This paper describes a high-power lithium-ion battery system that has been newly developed for application to hybrid electric vehicles (HEVs). The battery system was designed on the premise of an underfloor location so as to avoid sacrificing interior spaciousness while providing the power output and recharge performance required by the hybrid propulsion system. To meet these requirements, efforts were made to increase the specific power and to reduce the heat generation of the battery to previously unattained levels. As a result, exceptionally high specific power of 1,200 W/kg per cell, battery pack power of 25kW at 20% state of charge (SOC), and high charge/discharge efficiency of more than 95% in the urban driving schedule has been achieved. The battery pack is composed of two box-shaped modules designed with a low height in consideration of underfloor mountability.

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.

Nissan is installing a newly developed multi-link rear suspension in its new 240SX model. This suspension achieves maximum improvement in handling and stability through unique toe control, enhanced dynamic geometry and optimized alignment. The incorporation of attitude control also works to provide flat ride characteristics by greatly mitigating jacking up and squatting motions. This paper discusses the development objectives, results of CAD/CAE analyses and experimental data obtained in tests of the new suspension installed in the 240SX.

In December 2006, Nissan announced its Nissan Green Program 2010 (NGP 2010), a mid-term environmental action plan that includes initiatives to reduce vehicle emissions. In line with this plan, the company intends to introduce a new and original hybrid system in fiscal year 2010. Specifically, this system-called the “Infiniti Direct Response Hybrid”-is a one-motor, two-clutch parallel hybrid system that eliminates the need for a torque converter. It will be featured in the 2012 Infiniti M35 Hybrid and provides the following advantages. 1 Significant improvement in fuel economy even in Highway driving 2 Better response and a more direct feeling 3 Lightweight and low cost This one-motor, two-clutch system without torque converter possesses a simple but highly capable architecture that is new to the passenger vehicle segment.

The performance capabilities which hold the key to the acceptance of electric vehicles (EVs) includes range and acceleration. Range can be effectively extended by increasing the size of the batteries used, but it requires a trade-off with acceleration performance which deteriorates due to the increased weight. The FEV-II and Prairie Joy EV exhibited at the 1995 Tokyo Motor Show were equipped with high-performance lithium-ion batteries that achieve both high energy and power densities, to provide an excellent balance of range and acceleration. Futher more, the batteries exceptionally high charging efficiency enables them to accept regenerative energy effectively. This feature improves range, and also allows the battery state of charge (SOC) to be determined accurately. This characteristic was used to develop a highly accurate battery model which was incorporated in a simulation program for predicting EV performance.

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 contrast to the conventional two-stage cam drive system with a 9.52- mm pitch roller chain, a newly developed silent chain with a 6.35-mm pitch has made it possible to achieve a single-stage system. One traditional drawback of silent chains has been wear elongation. In developing the new chain, reliability was substantially improved by identifying the factors causing wear elongation and their effects and also by optimizing the characteristics of the chain components. The application of this single-stage cam drive system to the new QG engine series has resulted in reduced chain noise, a more compact cylinder head and significant weight savings due to the smaller part count and other improvements.

An Adaptive Cruise Control system with stop-and-go capability has been developed to reduce the driver's workload in traffic jams on expressways. Based on an analysis of driving behavior characteristics in expressway traffic jams, a control system capable of modeling those characteristics accurately has been constructed to provide natural vehicle behavior in low-speed driving. The effectiveness of the system was evaluated with an experimental vehicle, and the results confirmed that it reduces the driver's workload. This paper presents an outline of the system and its effectiveness along with the experimental results.

Recent environmental concerns such as atmospheric pollution and energy conservation have intensified the need to develop pollution-free, energy-efficient vehicles. One such solution is the electric automobile which draws its power from rechargeable batteries. There are few vehicles on the road today because present batteries can store very little energy compared with that of a tank of gasoline. To obtain adequate range, this concept vehicle adopts a new battery which can be recharged to 40% of capacity in six minutes. This super quick charging system makes it possible to recharge the batteries at an electric recharging station just as gasoline-powered vehicles are refilled at service stations. The electric concept vehicle also has improved aerodynamics, reduced rolling resistance and a lighter curb weight, which help to assure adequate range.

The purpose of this study was to develop a simple optimization method for use in designing vibration insulators. With this method, stiffness, location and inclination of each insulator are used as design parameters. A performance index consisting of vehicle modal parameters expressed as eigenvalues and eigenvectors has been constructed to evaluate low-frequency idle/shake performance and higher frequency vibration performance involving road/engine inputs. Using this performance index and the sensitivity of the modal parameters, a designer can easily find a suitable direction for optimizing mount performance and thereby obtain a stable solution. The new method was employed to optimize an engine mount system. Experimental data obtained on the system validated the accuracy of the calculated results and showed an improvement in idle/shake performance. This method is a useful tool in designing optimum vibration insulators.

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.

Nissan has recently developed and begun driving tests of a fuel cell vehicle equipped with a methanol reformer that produces hydrogen through the use of a catalyst to induce chemical reactions between methanol and water. With this onboard fuel cell system, only methanol in the form of a liquid fuel needs to be supplied, making the system highly practical as an automotive powertrain for near-future application. The Nissan Fuel Cell Vehicle (FCV) adopts a high-efficiency neodymium magnet synchronous traction motor combined with lithium-ion batteries that enable the vehicle to achieve optimum electric power by switching between a fuel cell-powered driving mode and a battery-powered driving mode. This presentation will cover the current status of the FCV development program and driving test results.