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Technical Paper

Engine Application of a Battery Voltage-Driven DI Fuel Injection System

2001-03-05
2001-01-0986
Every fuel injection system for DI gasoline engines has a DC-DC converter to provide high, stabile voltage for opening the injector valve more quickly. A current control circuit for holding the valve open is also needed, as well as a large-capacity capacitor for pilot injection. Since these components occupy considerable space, an injector drive unit separate from the ECU must be used. Thus, there has been a need for a fuel injection system that can inject a small volume of fuel without requiring high voltage. To meet that need, we have developed a dual coil injector and an opening coil current control system. An investigation was also made of all the factors related to the dynamic range of the injector, including static flow rate, fuel pressure, battery voltage and harness resistance. Both efforts have led to the adoption of a battery voltage-driven fuel injector.
Technical Paper

A Single-chip RISC Microcontroller Boarding on MY1998

1997-02-24
970863
This paper presents a single-chip 32bit RISC microcontroller boarding on MY1998 dedicated to highly complicated powertrain management. The high performance 32bit RISC CPU provides the only solution to meet requirements of drastic CPU performance enhancement and integration. Furthermore, a 32bit counter, based on a 20 MHz clock, and a 32bit multiplier make possible misfire detection and precise analysis of the engine management strategy, especially cylinder individual air-fuel ratio control.
Technical Paper

A New Engine Control System Using Direct Fuel Injection and Variable Valve Timing

1995-02-01
950973
A new engine drivetrain control system is described which can provide a higher gear ratio and leaner burning mixture and thus reduce the fuel consumption of spark ignition engines. Simulations were performed to obtain reduced torque fluctuation during changes in the air - fuel ratio and gear ratio, without increasing nitrogen oxide emissions, and with minimum throttle valve control. The results show that the new system does not require the frequent actuation of throttle valves because it uses direct fuel injection, which increases the air - fuel ratio of the lean burning limit. It also achieves a faster response in controlling the air mass in the cylinders. This results in the minimum excursion in the air - fuel ratio which in turn, reduces nitrogen oxide emissions.
Technical Paper

Smooth Gear Shift Control System Using Estimated Torque

1994-03-01
941013
An automotive powertrain total control system using estimated output shaft torque has been investigated in order to enhance drivability and improve fuel economy. The system provides efficient control for both the engine and transmission which leads to an enhancement in drivability by reducing shocks during gear shifts. This paper describes a new smooth gear shift control method using the total control system. By use of the estimated output shaft torque, it is possible to detect accurately the fluctuation condition and the start time of the inertia phase, which are important factors affecting shock occurrence. Torque feedback, got from estimated torque, was applied to the control of engine output shaft torque during shifts. The optimum hydraulic pressure, also got from estimated torque, was applied to the clutch of the transmission during shifts.
Technical Paper

Mixture Formation During Cold Starting and Warm-up in Spark Ignition Engines

1996-02-01
960065
A thermodynamic analysis of mixture formation in cylinders that takes into account mixture inhomogeneity and the wall film is presented. Conditions for obtaining low hydrocarbon emission are clarified analytically as a function of the fuel mass of the wall film and inhomogeneity of the mixture. Optimum processes for atomizing and vaporizing fuel are presented to reduce the inhomogeneity and the fuel mass of the film.
Technical Paper

Aeroacoustic Analysis of Transonic Helicopter Rotor Noise

1994-03-01
940041
The viscous effect on the high-speed impulsive (HSI) noise for a helicopter rotor has been investigated by using a combined method of computational fluid dynamics (CFD) techniques with the extended Kirchhoff's equation. The pressure distributions around a rotor blade are obtained by Euler and Navier-Stokes equations to capture a precise shock behavior. The Kirchhoff's equation extended to a moving surface is applied to calculate the acoustic pressures at the observer point. In this calculation, the pressures and pressure gradients on the Kirchhoff surface, in which all the acoustic sources are enclosed, are obtained by using CFD techniques. In order to estimate the effect of the viscosity on the acoustic pressures, two types of turbulence model in Navier-Stokes calculations are used. One is Baldwin-Lomax model and the other is Coakley's q - ω model.
Technical Paper

Numerical and Experimental Study of Drag Characteristics of HLFC Airfoils in High Subsonic, High Reynolds Number Flows

1994-03-01
940034
Hybrid laminar flow control (HLFC) is one of the most practically promising aircraft drag reduction technologies. We have investigated both numerically and experimentally aerodynamic characteristics of HLFC airfoil and wing at high subsonic, high Reynolds number conditions. In this paper we report the result of a wind tunnel test on drag characteristics of two-dimensional HLFC airfoils with porous and slot suction approach under some adverse factors against laminar flow, and a numerical analysis of the wind tunnel data, which is based on the boundary layer calculation with new transition prediction method allowed for the adverse factors and the Squire-Young drag formula.
Technical Paper

In-Flight Simulator Evaluation of a Flight Reference Display for Powered-Lift STOL Aircraft

1994-03-01
940013
A new flight reference display for powered-lift STOL aircraft was proposed and evaluated in actual flight environment. The display was developed to provide a simple monitoring system of STOL safety margins with good handling characteristics in place of a speed indicator. Using this display, pilots repeated simulated approaches of the experimental jet STOL “ASKA” using the VSRA as an in-flight simulator. In the evaluation, emphasis was placed on agreement between the display and the motion cues experienced by the pilot. Pilot comments and flight data confirmed satisfactory control characteristics and safety margin presentation of the display.
Technical Paper

A Preliminary Evaluation Test of GPS/DGPS Navigation System

1994-03-01
940012
The National Aerospace Laboratory (NAL) has been conducting basic research on the future landing navigation system of airplanes and a proposed future unmanned reentry space vehicle, using NAL research airplane Dornier Do-228 in which a Collins NAVCORE- I GPS C/A receiver was installed. A ground-to-air data link system was developed in order to realize the real time DGPS operation which improves accuracy. In this paper, experimental evaluation test results of not only GPS stand-alone operation but also DGPS operation are discussed. Since the navigation algorithm in the NAVCORE- I receiver could not be modified, this paper mainly discusses the difference of the two operations. In fixed point ground tests, ground and onboard GPS receivers were connected to the same antenna in order to avoid common errors, and both receivers output positions were compared with a reference map position. In the flight tests, approach/landing flights were conducted.
Technical Paper

Flight Path Control for the Approach and Landing of the Quiet STOL Experimental Aircraft ASKA

1994-03-01
940001
The Upper Surface Blowing STOL experimental aircraft ASKA, was developed and flight tested by the National Aerospace Laboratory of Japan. The ASKA operated well on the backside of the drag curve, and because of this flight path control was accomplished with the throttle lever (thrust) during approach and landing. To compensate for the sluggish flight path response caused by the thrust response lag, the flight path control law put in stability and control augmentation system. Flight tests were conducted to evaluate flight path and airspeed response characteristics. This paper describes ASKA's flight path and airspeed response characteristics, as well as construction of the flight path control system.
Technical Paper

Effect of Spray Characteristics on Combustion in a Direct Injection Spark Ignition Engine

1998-02-23
980156
Meeting the future exhaust emission and fuel consumption standards for passenger cars will require refinements in how the combustion process is carried out in spark ignition engines. A direct injection system decrease fuel consumption under road load cruising conditions, and stratified charge of the fuel mixture is particularly effective for ultra lean combustion. On the other hands, there are requirements for higher output power of gasoline engines. A direct injection system for a spark ignition engine is seen as a promising technique to meet these requirements. To get higher output power at wide open throttle conditions, spray characteristics and in-cylinder air flow must be optimized. In this paper, the engine system, which has a side injection type engine and flat piston, was investigated. We tried some injectors, which have different spray characteristics, and examined effects of spray characteristics on combustion of the direct injection gasoline engine.
Technical Paper

Numerical Analysis for the Small Positive Pressure Control System of CEEF

1997-07-01
972516
It is necessary to develop a small positive pressure control system for the closed ecology experiment facility (CEEF) to protect against over-differential pressure loading. In the present study, a numerical method was developed to calculate the quantity of state of the closed module, which is fitted with rubber buffers, for the small positive pressure control system. Experiments to examine the pressure change of the closed module were carried out at CEEF. Comparison of calculated and experimental results showed that the present dynamic simulation is suited to estimating the quantity of state of the closed module.
Technical Paper

Development of a Three-Dimensional Bird's-eye View Map Drawing Technique for Car Navigation Systems

1998-02-23
980605
In this paper, a newly developed three-dimensional (3D) bird's-eye view map drawing technique for car navigation systems is described. Conventional navigation systems give pseudo-perspective views which can not express ruggedness like hills and valleys. Our newly developed navigation system can display undulation of the land from viewpoints above and behind the current position, so that ups and downs of roads along with the driver's destination can be seen easily. The 3D-road map is not only effective during navigation but also during route planning, because it assists in searching for fine views before travel. In order to achieve the 3D-map view, we developed graphics software libraries, which work on a 32-bit RISC processor and on a low-cost graphics accelerator LSI with texture mapping capability. The graphics software libraries are constructed with three stages, the perspective projection stage, visible-surface determination stage, and rendering stage.
Technical Paper

A State Adaptive Control Algorism for Vehicle Suspensions

1988-11-01
881769
This paper describes a state adaptive control method for vehicle suspensions proposed by Hitachi, Ltd. The objective of the control is to improve riding comfort and driving stability in reaction to road iregularities, exterior wind forces, and changes in vehicle loads as well as in reaction to inertial changes during cornering, breaking, and accelerating. The objective is attained by making considerable use of the relative displacement data between the body and the suspension. The state adaptive control system includes four shock absorbers whose damping forces can be tuned in three stages, four height sensors which measure the relative displacement, a vehicle speed sensor, and a microcomputer which decides the optimal damper stage. The validity of the proposed control method is shown through computer simulations and actual driving experiments. Vertical acceleration is reduced by about 55 % by switching from the soft damper to the hard damper in a computer simulation.
Technical Paper

Optical Multiplexed Transmission System using High Temperature Polymer Fiber

1989-02-01
890200
A multiplexed transmission system utilizing newly developed optical polymer has been proposed. The system is composed of a star-shaped optical network, in which optical signals can be transmitted bi-directionally through a fiber and optical branches between the central and local controllers. The new polymer optical fiber has been developed and adopted for this system, and it was designed to be durable to the high temperature in automotive engine rooms. The high temperature resistibility of the fiber has been achieved with utilization of a thermo-setting resin for the core materials. The optical loss characteristics of the fiber is as low as 0.50 dB/m at 660 nm wavelength.
Technical Paper

Air-Fuel Ratio Sensor Utilizing Ion Transportation in Zirconia Electrolyte

1991-02-01
910501
To detect an air-fuel ratio in wide range is very important to control the automotive engines with low fuel consumption and low exhaust emissions. Although the application of zirconia electrolyte for this purpose has been proposed by the authors several years ago, there remained several problems due to the contamination of gas diffusion apertures which are exposed to the exhaust gas environment. Here the behavior of ions transported in zirconia electrolyte have been analyzed to optimize the structure and characteristics, and to guarantee the long life operation of sensor. Gas contents and their reactions in combustion process under the wide range air-fuel ratio have been analyzed, and these results were reflected to the analysis of ion transportation in zirconia electrolyte. Experimental results supported the analytical results, and they showed the possibilities of long life operation of zirconia air-fuel ratio sensor utilizing ion transportation phenomena.
Technical Paper

An Automatic Parameter Matching for Engine Fuel Injection Control

1992-02-01
920239
An automatic matching method for engine control parameters is described which can aid efficient development of new engine control systems. In a spark-ignition engine, fuel is fed to a cylinder in proportion to the air mass induced in the cylinder. Air flow meter characteristics and fuel injector characteristics govern fuel control. The control parameters in the electronic controller should be tuned to the physical characteristics of the air flow meter and the fuel injectors during driving. Conventional development of the engine control system requires a lot of experiments for control parameter matching. The new matching method utilizes the deviation of feedback coefficients for stoichiometric combustion. The feedback coefficient reflects errors in control parameters of the air flow meter and fuel injectors. The relationship between the feedback coefficients and control parameters has been derived to provide a way to tune control parameters to their physical characteristics.
Technical Paper

Development of an On-Board Class A Local Area Network System

1992-02-01
920229
The growing number of electronic components used in automobiles lately has given rise to problems concerning the increasing number, size and weight of the wiring harnesses. As one approach to resolving these problems, the authors proposed a multiplex method based on the direction of signal flow in 1988 (SAE880589). However, the need to reduce the number of wiring harnesses circuits further made it necessary to develop a more sophisticated system. This paper presents an on-board Class A local area network (LAN) system that overcomes the problems in conventional multiplexing systems through the use of a master-slave configuration, a polling selection method and a system that integrates of electronic circuits with switch modules.
Technical Paper

Aero-Structural Integrated Design of Forward Swept Wing

1991-09-01
912021
Forward swept wing (FSW) is known to have excellent performance relative to aft swept wing. The practical application, however, has been limited due to its structural divergence characteristics. The current progress in materials, especially anisotropic composites has opened up new future for FSW. This paper describes design study of FSW for transonic transport looking for high drag divergence performance. Inverse code is applied to FSW aerodynamic design to achieve isobar design concept. The performance is verified by transonic wind tunnel test. The paper also mentions the development of aero-structural integrated design tool, a combination of aerodynamic analysis code and structural analysis code, which is essential to FSW wing development.
Technical Paper

Aerodynamic Development of Boundary Layer Control System for NAL QSTOL Research Aircraft ‘ASKA’

1991-09-01
912010
“ASKA” developed by National Aerospace Laboratory (NAL) is a quiet, short take-off and landing (QSTOL) research aircraft adopting upper surface blowing (USB) concept as a powered high lift system. To achieving sufficient STOL performance by augmenting stall angle of attack and roll control power, blowing BLC technique was applied to the outboard leading edges and ailerons.Supplied high pressure air to save the BLC piping space,the BLC system which was fit for use of high pressure air was developed. The BLC system, in which BLC air is discharged by a series of discrete jets from small drilled holes (0.8 ∼ 3.0 mm in diameter) arranged in a raw, is one of the unique features of the aircraft. In this paper, the summaries of aerodynamic development of the BLC system are described except for the air piping system.
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