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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

Model-Based Calibration Process for Producing Optimal Spark Advance in a Gasoline Engine Equipped with a Variable Valve Train

2006-10-16
2006-01-3235
The increasing number of controllable parameters in modern engine systems leads to complicated and enlarged engine control software. This in turn has led to dramatic increases in software development time and costs in recent years. Model-based control design seems to be an effective way to reduce development time and costs. In the present study, we have developed model-based methodologies for the engine calibration process using an engine cycle simulation technique combined with a regression analysis of engine responses. From the results it was clear that the engine cycle simulation technique was useful in the engine calibration process, if the empirical parameters included in physical models were adjusted at typical sampling-points in several engine speeds and loads. The cycle simulation produced a multi-dimensional MBT map, and a response surface method was employed in the modeling of the engine map dataset using a polynomial equation.
Technical Paper

An Accurate Torque-based Engine Control by Learning Correlation between Torque and Throttle Position

2008-04-14
2008-01-1015
In recent years, integrated vehicle control systems have been developed to improve fuel economy and safety. As a result, engine control is shifting to torque-based systems for throttle / fuel / ignition control, to realize an engine torque demand from the system. This paper describes torque-based engine control technologies for SI (Spark Ignition) engine to improve torque control accuracy using a feedback control algorithm and an airflow sensor.
Technical Paper

Improvement of Thermal Efficiency Using Fuel Reforming in SI Engine

2010-04-12
2010-01-0584
Hydrogen produced from regenerative sources has the potential to be a sustainable substitute for fossil fuels. A hydrogen internal combustion engine has good combustion characteristics, such as higher flame propagation velocity, shorter quenching distance, and higher thermal conductivity compared with hydrocarbon fuel. However, storing hydrogen is problematic since the energy density is low. Hydrogen can be chemically stored as a hydrocarbon fuel. In particular, an organic hydride can easily generate hydrogen through use of a catalyst. Additionally, it has an advantage in hydrogen transportation due to its liquid form at room temperature and pressure. We examined the application of an organic hydride in a spark ignition (SI) engine. We used methylcyclohexane (MCH) as an organic hydride from which hydrogen and toluene (TOL) can be reformed. First, the theoretical thermal efficiency was examined when hydrogen and TOL were supplied to an SI engine.
Technical Paper

A Study of Friction Characteristics of Continuously Variable Valve Event & Lift (VEL) System

2006-04-03
2006-01-0222
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.
Technical Paper

Smooth Gear Shift Control Technology for Clutch-to-Clutch Shifting

1999-03-01
1999-01-1054
An automatic transmission without a one-way clutch for a small sized, light weight automatic transmission is presented. The factor of torque fluctuation occurrence during shifting of the transmission increases so that the shifting is executed by controlling two wet clutches electronically in place of the one-way clutch and the wet clutch. Therefore, it is necessary to develop a new smooth gear shift control technology for clutch-to-clutch shifting on an automatic transmission without a one-way clutch. The control technology has desirable clutch-to-clutch shift control, learning control and robust control which apply to accurate signals obtained by an observation method. Smooth shifts during clutch-to-clutch shifting can be realized by recognizing clutch change-over time using a calculated acceleration and an input/output speed ratio of the transmission.
Technical Paper

Evaluation of Parallel Executions on Multiple Virtual ECU Systems

2018-04-03
2018-01-0011
We have developed a cooperative simulation environment for multiple electronic control units (ECUs) including a parallel executions mechanism to improve the test efficiency of a system, which was designed with multiple ECUs for autonomous driving. And we have applied it to a power window system for multiple ECUs with a controller area network (CAN). The power window model consists of an electronic-mechanical model and a CPU model. Each simulator with a different executions speed operates in parallel using a synchronization mechanism that exchanges data outputted from each simulator at a constant cycle. A virtual ECU simulated microcontroller hardware operations and executed its control program step-by-step in binary code to test software for the product version. As co-simulation technology, a mechanism that synchronously executes heterogeneous simulators and a model of an in-vehicle communication CAN connecting each ECU were developed.
Technical Paper

Development of Predictive Powertrain State Switching Control for Eco-Saving ACC

2017-03-28
2017-01-0024
In recent years, improvement of in-use fuel economy is required with tightening of exhaust emission regulation. We assume that one of the most effective solutions is ACC (Adaptive Cruise Control), which can control a powertrain accurately more than a driver. We have been developing a fuel saving ADAS (Advanced Driver Assistance System) application named “Sailing-ACC”. Sailing-ACC system uses sailing stop technology which stops engine fuel injection, and disengages a clutch coupling a transmission when a vehicle does not need acceleration torque. This system has a potential to greatly improve fuel efficiency. In this paper, we present a predictive powertrain state switching algorithm using external information (route information, preceding vehicle information). This algorithm calculates appropriate switching timing between a sailing stop mode and an acceleration mode to generate a “pulse-and-glide” pattern.
Journal Article

Virtual Engine System Prototyping with High-Resolution FFT for Digital Knock Detection Using CPU Model-Based Hardware/Software Co-simulation

2009-04-20
2009-01-0532
We have developed a full virtual engine system prototyping platform with 4-cylinder engine plant model, SH-2A CPU hardware model, and object code level software including OSEK OS. The virtual engine system prototyping platform can run simulation of an engine control system and digital knock detection system including 64-pt FFT computations that provide required high-resolution DSP capability for detection and control. To help the system design, debugging, and evaluation, the virtual system prototyping consists of behavior analyzer which can provide the visualization of useful CPU internal information for control algorithm tuning, RTOS optimization, and CPU architecture development. Thus the co-simulation enables time and cost saving at validation stage as validation can be performed at the design stage before production of actual components.
Journal Article

Multi-Fidelity Total Integrated Simulation Technology for High Pressure Pump with Squeeze Film Effect

2017-03-28
2017-01-1325
Automotive fuel can be efficiently combusted by injecting it into the cylinders at high pressure to atomize it to pass the regulations for exhaust gas and fuel economy. For this reason, automotive companies have developed direct injection engines, which can inject gasoline into the cylinders directly. Furthermore, the demand for lower-noise high pressure pumps is also increasing from the viewpoint of automotive comfort. Since the valve velocity and noise level will increase as the pressure in fuel pumps increases, noise problems need to be solved under the high pressure conditions. Accordingly, the valve motion should be predicted with high accuracy under operating conditions to evaluate the noise caused by valve impingement. In addition, the squeeze film effect phenomenon will occur in the physical fuel pumps affect the prediction of the noise level caused by valve impingement.
Technical Paper

Development of Breath-Alcohol-Detection System

2016-04-05
2016-01-1498
The problem of high fatal accident rates due to drunk driving persists, and must be reduced. This paper reports on a prototype system mounted on a car mock-up and a prototype portable system that enables the checking of the drivers’ sobriety using a breath-alcohol sensor. The sensor unit consists of a water-vapor-sensor and three semiconductor gas sensors for ethanol, acetaldehyde, and hydrogen. One of the systems’ features is that they can detect water vapor from human-exhaled breath to prevent false detection with fake gases. Each gas concentration was calculated by applying an algorithm based on a differential evolution method. To quickly detect the water vapor in exhaled breath, we applied an AC voltage between the two electrodes of the breath-water-vapor sensor and used our alcohol-detection algorithm. The ethanol level was automatically calculated from the three gas sensors as soon as the water vapor was detected.
Technical Paper

Improved Thermal Efficiency Using Hydrous Ethanol Reforming in SI Engines

2013-09-08
2013-24-0118
The internal combustion engines waste large amounts of heat energy, which account for 60% of the fuel energy. If this heat energy could be converted to the output power of engines, their thermal efficiency could be improved. The thermal efficiency of the Otto cycle increases as the compression ratio and the ratio of specific heat increase. If high octane number fuel is used in engines, their thermal efficiency could be improved. Moreover, thermal efficiency could be improved further if fuel could be combusted in dilute condition. Therefore, exhaust heat recovery, high compression combustion, and lean combustion are important methods of improving the thermal efficiency of SI engines. These three methods could be combined by using hydrous ethanol as fuel. Exhaust heat can be recovered by the steam reforming of hydrous ethanol. The reformed gas including hydrogen can be combusted in dilute condition. In addition, it is cooled by directly injecting hydrous ethanol into the engine.
Technical Paper

Method for Determining Thermal Resistances in Coupled Simulator: For Electric Valve Timing Control System

2015-04-14
2015-01-1301
We developed a thermal calculation 1D simulator for an electric valve timing control system (VTC). A VTC can optimize the open and close timing of the intake and exhaust valves depending on the driving situation. Since a conventional VTC is driven hydraulically, the challenges are response speed and operation limit at low temperature. Our company has been developing an electric VTC for quick response and expansion of operating conditions. Currently, it is necessary to optimize the motor and reduction gear design to balance quicker response with downsizing. Therefore, a coupled simulator that can calculate electricity, mechanics, control, and thermo characteristics is required. In 1D simulation, a thermal network method is commonly used for thermal calculation. However, an electric VTC is attached to the end of a camshaft; therefore, determining thermal resistances is difficult. We propose a method of determining thermal resistances, using both theoretical and experimental approaches.
Journal Article

A Study of a Multiple-link Continuously Variable Valve Event and Lift (VVEL) System

2008-06-23
2008-01-1719
A new variable valve event and lift (VVEL) system has been developed by applying a multiple-link mechanism. This VVEL system can continuously vary the valve event angle and lift over a wide range from an exceptional small event angle and small lift and to a large event angle and large lift. This capability offers the potential to improve fuel economy, power output, emissions and other parameters of engine performance. The valve lift characteristics obtained with the VVEL system consist of a synthesis of the oscillatory motion characteristics of the multiple-link mechanism and the oscillating cam profile. With the multiple-link mechanism, the angular velocity of the oscillating cams varies during valve lift, but the valve lift characteristics incorporate both gentle ramp sections and sharp lift sections, the same as a conventional engine.
Journal Article

Injection Quantity Range Enhancement by Using Current Waveform Control Technique for DI Gasoline Injector

2014-04-01
2014-01-1211
We have achieved injection quantity range enhancement by using the current waveform control technique for direct injection (DI) gasoline injectors. In this study, we developed an injection quantity simulator to find out the mechanism of non-linear characteristics. We clarified the non-linear production mechanism by using the simulator. This simulator is a one-dimensional simulator that incorporates calculation results from both unsteady electromagnetic field analysis and hydraulic flow analysis into the motion equation of this simulation code. We investigated the relation between armature and the injection quantity by using the simulator. As a result, we clarified that the non-linearity was produced by the bounce of the armature in the opening action. Thus, we found that it is effective to reduce the armature bounce to improve the linearity of the injection quantity characteristics.
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

Engine Knock Detection Using Multi-Spectrum Method

1992-02-01
920702
High engine load and over-heated engine cylinder are the main causes of engine knock. When knock occurs in an engine, vibrations composed of several specific resonant frequencies occur. Some of these resonant frequencies are missed stochastically because specific resonant frequencies are caused by different resonant vibration modes in an engine cylinder. However, a conventional knock detector can only measure a fixed resonant frequency using a band-pass filter. This paper presents a multi-spectrum method which greatly improves knock detection accuracy by detecting the knock resonance frequencies from several specific vibration frequencies. Through overcoming the random occurrences of knock resonant frequencies by selecting specific frequencies, knock detection accuracy can be greatly improved. We studied a high precision knock detection method using real-time frequency analysis and a piezoelectric accelerometer on a V-6 engine.
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

Numerical Simulation System for Analyzing Fuel Film Flow in Gasoline Engine

1993-03-01
930326
A new numerical simulation system has been developed which predicts flow behavior of fuel film formed on intake port and combustion chamber walls of gasoline engines. The system consists of a film flow model employing film thickness as a dependent variable, an air flow model, and a fuel spray model. The system can analyze fuel film flow formed on any arbitrary three-dimensional configuration. Fuel film flow formed under a condition of continuous intermittent fuel injection and steady-state air flow was calculated, and comparison with experimental data showed the system possessing ability of qualitative prediction.
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.
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