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With conventional float-type fuel level sensor's, measurement errors when the vehicle is on an incline or going around corners. Now, a highly-accurate measuring system employing an electrostatic capacity sensor is developed for practical application. This sensor is composed of multiple electrode plates formed alone a allows accurate measurement of regaining fuel even in tanks of irregular shapes. Also, since this sensor comes a unit, it is easier to replace. The system furthermore, employs software provided with averaging, memory storage, and permittivity correction functions in order to elminate the effects of fuel level fluctuations and pressure changes within the tank during driving along with the effect of fuels with different permittivity.

Research is under way on an engine system [1] that achieves a variable compression ratio using a multiple-link mechanism between the crankshaft and pistons for the dual purpose of improving fuel economy and power output. At present, there is no database that allows direct judgment of the feasibility of the specific sliding parts in this mechanism. In this paper, the feasibility was examined by making a comparison with the sliding characteristics and material properties of conventional engine parts, for which databases exist, and using evaluation parameters based on mixed elasto-hydrodynamic (EHD) lubrication calculations. In addition, the innovations made to the mixed EHD calculation method used in this study to facilitate calculations under various lubrication conditions are also explained, including the treatment of surface roughness, wear progress and stiffness around the bearings.

Nissan has developed a new GA16DE engine for use in the new 1991 Sentra. The major development aims for this engine were to achieve ample torque at low to intermediate engine speed and smooth throttle response. These aims, of course, had to be compatible with good fuel economy, quietness, maintenance-free operation and high reliability. In addition, It was necessary to achieve a compact package size despite the twin-cam design. All of those objectives have been attained through the use of a super-long and aerodynamic intake system, variable valve timing control, a low friction, maintenance-free, direct acting valve system, dual direction fuel injectors, and a two-stage cam drive system. This paper discuss the major development objectives, basic engine structure and principal component parts.

There has been a growing need to develop more compact automatic transmissions with a greater number of speeds for better fuel economy and better driveability. This study investigated a method for determining suitable planetary gear trains for today's transmissions. A computer program has been developed for application to five-speed transmissions consisting of two planetary gearsets. By analyzing various gear train possibilities, the program can identify which gearsets are suitable for different conditions, including the number of speeds, the number of binding elements, topological suitability and other factors.

As a new generation sports car engine to lead the field in the 1990s, a 3.0 liter, 60°V, type 6 cylinder, 4 cam, 24 valve engine (VG30DETT) has been developed to achieve the utmost in high performance levels and reliability. it has been mounted on the new model 300ZX and announced in the North America and Japanese markets. The VG30DETT engine is based on the previous VG30DE engine (the engine mounted on the former model 300ZX designed for the market in Japan). The main components, the major driving and the lubrication systems including such parts as the crank shaft,con-rod, cylinder block, piston, exhaust manifold, and oil pan of the VG30DE were thoroughly reviewed and revised. The VG30DETT engine is the result of redesigning the structure of the engine itself and its parts and components to assure durability under, high-level performance requirements.

A robotic driver has been designed on the basis of an analysis of a human driver's action in following a given driving schedule. The self-learning algorithm enables the robot to learn the vehicle characteristics without human intervention. Based on learned relationships, the robotic driver can determine an appropriate accelerator position and execute other operations through sophisticated calculations using the future scheduled vehicle speed and vehicle characteristics data. Compensation is also provided to minimize vehicle speed error. The robotic driver can reproduce the same types of exhaust emission and fuel economy data obtained with human drivers with good repeatability. It doesn't require long preparation time. Thereby making it possible to reduce experimentation work in the vehicle development process while providing good accuracy and reliability.

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.

Technologies for improving the fuel economy of gasoline engines have been vigorously developed in recent years for the purpose of reducing CO2 emissions. Increasing the compression ratio is an example of a technology for improving the thermal efficiency of gasoline engines. A significant issue of a high compression ratio engine for improving fuel economy and low-end torque is prevention of knocking under a low engine speed. Knocking is caused by autoignition of the air-fuel mixture in the cylinder and seems to be largely affected by heat transfer from the intake port and combustion chamber walls. In this study, the influence of heat transfer from the walls of each part was analyzed by the following three approaches using computational fluid dynamics (CFD) and experiments conducted with a multi-cooling engine system. First, the temperature rise of the air-fuel mixture by heat transfer from each part was analyzed.

Driving tests were conducted using an experimental vehicle equipped with an adaptive cruise control system incorporating low-speed following capability in order to evaluate drivers' trust in a driver support system. The results revealed that the drivers' trust in the system declined in cases where the control algorithm produced vehicle behavior that was inconsistent with their expectations. However, that decline in trust ceased to be observed as the drivers' understanding of the system improved. This result suggests a correlation between their understanding of the system and trust in it.

A continuously variable valve event and lift (VEL) system, actuated by oscillating cams, can provide optimum lift and event angles matching the engine operating conditions, thereby improving fuel economy, exhaust emission performance and power output. The VEL system allows small lift and event angles even in the engine operating region where the required intake air volume is small and the influence of valvetrain friction is substantial, such as during idling. Therefore, the system can reduce friction to lower levels than conventional valvetrains, which works to improve fuel economy. On the other hand, a distinct feature of oscillating cams is that their sliding velocity is zero at the time of peak lift, which differs from the behavior of conventional rotating cams. For that reason, it is assumed that the friction and lubrication characteristics of oscillating cams may differ from those of conventional cams.

Various radar systems have been proposed as collision avoidance sensors for automatic braking and warning applications. Practical use of laser radar systems is near with the introduction of high power, high reliability laser diodes. Utilizing these new devices, a laser radar system has been adapted for measuring the distance to objects in its path. It was first shown that reflectors on the rear of the automobile possess high reflectivity and sharp directivity. Given these characteristics, a compact laser radar system was tested that employed 12W laser diodes and PIN photodiodes. The maximum range of approximately 100 m was obtained. Furthermore, the ability to discriminate other vehicles from roadside objects was achieved by detecting discontinuity in measured distance data through a microprocessor. These results show that the performance of laser radar is comparable to that of microwave radar.

A study was made on a control method for an adaptive cruise control (ACC) system that uses vehicle-to-vehicle communication to achieve a substantial improvement in string stability and natural headway distance response characteristics at lower levels of longitudinal G. A control system using model predictive control was constructed to achieve this desired ACC vehicle behavior. Control simulations were performed using experimental data obtained in vehicle-following driving tests conducted on a proving ground course using a platoon of three manually driven vehicles. The results showed that the proposed ACC system satisfactorily achieved higher levels of required ACC performance.

The ways in which vehicles are used in the field are continually becoming more diverse. In order to provide the optimum solution with respect to performance and weight, it is necessary to be able to assure vehicle endurance reliability with a high degree of accuracy in relation to the manner of use in each market. This situation has increased the importance of accurately quantifying the ways in which vehicles are used in the field and of designing vehicles with sufficient endurance reliability to match the usage requirements. This report presents a “market model” by which the manner of usage in the field can be treated quantitatively using combinations of environmental factors that influence the road load, drive load and corrosion load, representing typical loads vehicles must withstand.

This paper concerns research on an emission control system aimed at reducing emission levels to well below the ULEV standards. As emission levels are further reduced in the coming years, it is projected that measurement error will increase substantially. Therefore, an analysis was made of the conventional measurement system, which revealed the following major problems. 1. The conventional analyzer, having a minimum full-scale THC range of 10 ppmC, cannot measure lower concentration emissions with high accuracy. 2. Hydrocarbons are produced in various components of the measurement system, increasing measurement error. 3. Even if an analyzer with a minimum full-scale THC range of 1 ppmC is used in an effort to measure low concentrations, the 1 ppmC measurement range cannot be applied when the dilution air contains a high THC concentration. This makes it impossible to obtain highly accurate measurements. 4.

Technologies for improving the fuel economy of gasoline engines have been vigorously developed in recent years for the purpose of reducing CO2 emissions. Increasing the compression ratio for improving thermal efficiency and downsizing the engine based on fuel-efficient operating conditions are good examples of technologies for enhancing gasoline engine fuel economy. A direct-injection system is adopted for most of these engines. Direct injection can prevent knocking by lowering the in-cylinder temperature through fuel evaporation in the cylinder. Therefore, direct injection is highly compatible with downsized engines that frequently operate under severe supercharging conditions for improving fuel economy as well as with high compression ratio engines for which susceptibility to knocking is a disadvantage.

This paper proposes a new voice and data wireless communication method for telematics services. Data-voice (DV) modems have conventionally been used for simultaneous transmission of voice and data. With this method, however, one line is split between the data part and voice part. Lost data are retransmitted, but the voice signal is not resent because voice communication requires a real-time characteristic. The new voice and data wireless communication method proposed here switches voice to a voice line and data to a data line.

The aim of this study is to gain a better understanding of the mechanism of knocking with respect to flame propagation behavior based on 3D simulations conducted with the Universal Coherent Flamelet Model. Flame propagation behavior under the influence of in-cylinder flow was analyzed on the basis of the calculated results and experimental visualizations. Tumble and swirl flows were produced in the cylinder by inserting various baffle plates in the middle of the intake port. A comparison of the measured and calculated flame propagation behavior showed good agreement for various in-cylinder flow conditions. The results indicate that in-cylinder flow conditions vary the flame propagation shape from the initial combustion period and strongly influence the occurrence of knocking.

A key factor influencing the performance of a hybrid electric vehicle (HEV) is how the engine and motor-generator (MG) are combined with the vehicle. There have been several types of combinations such as power transfer by using the mechanical transmission of conventional vehicles or the electrical transmission originally designed for HEVs. The objectives of this research were to clarify fuel economy characteristics according to the type of power transfer system used and to identify the requirements for MG system development by analyzing MG operation conditions in each power transfer mode. HEV systems for passenger car use were modeled on the basis of a functional classification. Simulations were conducted using the characteristics of the power transfer systems as parameters to evaluate fuel economy tendencies under several driving modes. The mechanism of the fuel economy tendencies was then analyzed to evaluate quantitatively the effect of each power transfer system on fuel economy.

ASICs (Application-specific ICs) offer one solution to the problems of quality, cost and installability associated with the increasingly larger-capacity Electronic Control Units (ECUs) in automobiles. A method was, therefore, created for designing automotive ASICs. Using the method, three ASICs were developed which, together, incorporate all of the functions of the electronic instrument cluster. The core ASIC contains the speedometer and system functions, and the other two ASICs contain the tachometer and gauge functions, respectively. This set of three ASICs allows an electronic instrument cluster design which is two times more reliable, and one-second the cost that conventional systems (with a micro-processor and discrete components).

This paper describes a newly developed adaptive cruise control (ACC) system using continuously variable transmission (CVT) gear ratio control. This system provides excellent headway distance control performance at a reasonable cost. With this system, headway distance is measured with a laser radar, and the throttle position and CVT gear ratio are controlled under both acceleration and deceleration situations. The new ACC system consists of a target headway distance calculator, a headway distance controller, a vehicle velocity controller and a drive torque controller. Using a drive torque control method that was newly developed based on integrated control of engine torque and the CVT gear ratio, the following benefits are obtained. (1) It provides smoother acceleration and deceleration. (2) It maintains the target vehicle velocity on steep uphill and downhill grades. As a result, sufficient ACC performance can be attained even in 2.0-liter class vehicles.