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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.

This paper presents a new substrate for Lean NOx Traps (LNT) which enables high NOx conversion efficiency, even after long-term aging, when using alkali metals as the NOx adsorber. When a conventional metal honeycomb is used as the LNT substrate, the chromium in the metal substrate migrates into the washcoat and reacts with the alkali metals after thermal aging. In order to help prevent this migration, we have developed a new substrate where a fine -alumina barrier is precipitated to the surface of the metal substrate. The new substrate is highly capable of preventing migration of chromium into the washcoat and greatly enhances the NOx conversion. The durability of the new substrate and emission test using a test vehicle are also examined.

The increasing number of controllable parameters in modern engine systems has led to increasingly complicated and enlarged engine control software. This in turn has created dramatic increases in software development time and cost. Model-based control design seems to be an effective way to reduce development time and costs and also to enable engineers to understand the complex relationship between the many controllable parameters and engine performance. In the present study, we have developed model-based methodologies for the engine calibration process, employing engine cycle simulation and regression analysis. The reliability of the proposed method was investigated by validating the regression model predictions with measured data.

This paper proposes a new development method for highly reliable real-time embedded control systems using a CPU model-based hardware/software co-simulation. We take an approach that allows the full simulation of the virtual mechanical control system including CPU and object code level software. In this paper, Renesas SH-2A microcontroller model was developed on CoMET™ platform from VaST Systems Technology. A ETC (Electronic Throttle Control) system and engine control system were chosen to prove this concept. The ETB (Electronic Throttle Body) model on Saber® simulator from Synopsys® or engine model on MATLAB®/Simulink® simulator from MathWorks can be simulated with the SH-2A model. To help the system design, debug and evaluation, we developed an integrated behavior analyzer, which can display CPU behavior graphically during the simulation without affecting the simulation result, such as task level CPU load, interrupt statistics, software variable transition chart, and so on.

A new urea-dosing device with an active-ammonia production function was developed. This function is achieved by an electrically heated bypass passage with a hydrolysis catalyst for urea-to-ammonia conversion. The new device also has the function of mixing ammonia and exhaust gas. It is compact and has low-pressure loss by using the vortex occurring at the back of a static vane. We built a trial device for a small diesel engine and obtained steady state and transient data. The heated-bypass concept can be used in the aftertreatment system of passenger cars. Although active-ammonia production consumes electric power, a predictive calculation of power consumption (based on experimental results) shows that the developed bypass heater can suppress the energy consumption enough not to harm the high-energy efficiency of diesel engines.

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.

We have developed a model-based control for the air intake system in a variable valve engine, employing total engine simulation, the response surface method and multi-objective optimization scheme. In our technique, we performed the simulation model tuning and validation, followed by the creation of a dataset for the polynomial regression analysis of the charging efficiency. A D-optimal design, robust least squares method, and likelihood-ratio test were demonstrated to yield a robust and accurate control model. Coupling the total engine simulator with a genetic algorithm, model based calibration for optimal valve timing stored in lookup table was carried out under multiple objectives and restrictions. The reliability of the implementation control model, which considers the effect of gas dynamics in the intake system, was confirmed using a model-in-the-loop simulation.

Predicting the vibration of a motor gearbox assembly driven by a PWM inverter in the early stages of development is demanding because the assembly is one of the dominant noise sources of electric vehicles (EVs). In this paper, we propose a simulation model that can predict the transient vibration excited by gear meshing, reaction force from the mount, and electromagnetic forces including the carrier frequency component of the inverter up to 10 kHz. By utilizing the techniques of structural model reduction and state space modeling, the proposed model can predict the vibration of assembly in the operating condition with a system level EV simulator. A verification test was conducted to compare the simulation results with the running test results of the EV.

The purpose of this study is to develop model-based methodologies which employ thermo-fluid dynamic engine simulation and multiple-objective optimization schemes for engine control and calibration, and to validate the reliability of the method using a dynamometer test. In our technique, creating a total engine system model begins by first entirely capturing the characteristics of the components affecting the engine system's behavior, then using experimental data to strictly adjust the tuning parameters in physical models. Engine outputs over the full range of engine operation conditions as determined by design of experiment (DOE) are simulated, followed by fitting the provided dataset using a nonlinear response surface model (RSM) to express the causal relationship among engine operational parameters, environmental factors and engine output. The RSM is applied to an L-jetronic® air-intake system control logic for a turbocharged engine.

In order to reduce diesel NOx emissions, aftertreatment methods including LNT (Lean NOx Trap) and urea SCR (Selective Catalytic Reduction) have been researched. One of the shortcomings of urea SCR is its NOx reduction performance degradation at low exhaust gas temperatures and possible emission of unregulated byproducts. Here, a new type of a urea-dosing device to overcome these shortcomings is studied. This dosing device actively produces ammonia without depending upon the exhaust gas temperature, and designed for onboard application. The device incorporates an electrically heated bypass with a hydrolysis catalyst. An injector supplies urea solution into the bypass. The bypass is heated only when thermolysis is needed to produce ammonia (NH3). The hydrolysis catalyst further assists in the production of NH3. The ammonia gas obtained is then mixed with the main exhaust gas flow.

The role of sensors and sensing technologies for the next generation vehicle systems are discussed. The control systems for engines and power-train are expected to realize high efficiency with low pollution and comfort drivability. Vehicular safety and chassis control systems are expected to avoid many kinds of traffic accidents caused by the human errors of drivers. Vehicular information systems will help the drivers to get the information to manage their vehicles economically and efficiency. In every system mentioned above, sensors and sensing technologies are playing an increasingly important role. This paper introduces and discusses essential technologies for sensors and sensing which can be expected to bring the solutions to the future automotive systems.

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.

Most automatic transmissions are controlled in compliance with a predetermined program. Transient control during gear shift is also carried out according to a predetermined process. In this method a lot of labor is required to tune data tables. So we developed a tuning free system by feedback control using torque estimation technology and the experimental result is reported. Torque fluctuation during shift is detected and fed back to compare the torque reference, which is generated from the estimated torque itself. The engine torque is decreased by means of retarding the ignition spark advance, according to the comparison deviation. As a consequence of the feedback, the transient torque control is carried out without any tuning trouble, and better than usual torque fluctuation is obtained.

To detect difficult-to-find defects in automotive control systems, we have proposed a modeling method with a program slicing technique. In this method, a verifier adjusts the boundaries of source code to be extracted on a variable dependence graph, in a kind of data flow. We have developed software tools for this method and achieved a 35% decrease in total verification time on model checking. This paper provides some consideration on effective cases of the method from verification practices. There are two types of malfunction causes: one is the timing of processes (race conditions), and the other is complex logics. Each type requires different elements in external environment models. Furthermore, we propose regression verification based on the modeling method above, to further reduce verification time on model checking. The paper outlines tool extensions needed to realize regression verification.

The urea-SCR system is one of the most promising aftertreatment systems for future automotive diesel engines. We developed a urea dosing device with twin urea injectors for onboard applications, to enhance the NOx reduction performance at low exhaust temperatures and to lower the electric power consumption of the SCR system. The injectors operate with a single-phase urea solution, without air assist. Of the injectors, one is used to supply urea to a bypass passage routing the exhaust, during low exhaust temperatures. The other injector is located on the wall of the main exhaust duct, directly supplying urea to the exhaust. This direct injection method has a uniform spray distribution problem. A set of impact plates were used to distribute the spray. Impact plates have a high potential for deposition, but use of film boiling was considered. A thermal analysis was conducted and as a result, deposit conditions were theoretically derived. This was confirmed through experiments.

We developed a high-pressure fuel pump for a direct injection gasoline engine and used a hydraulic simulator to design it. A single plunger design is the major trend for high-pressure fuel pumps because of its simple structure and small size. However, the single plunger causes large pressure pulsation and an unstable flow rate, especially at high engine speed. Therefore, a fuel-pipe layout that inhibits the pressure pulsation and a flow-rate control that stabilizes the flow are the most important challenges in pump design. Our newly developed hydraulic simulator can evaluate the dynamic characteristics of a total fuel supply system, which consists of pump, pipe, injector, and control logic. Using this simulator, we have improved fuel flow by optimizing the outlet check valve lift and the cam profile, and we reduced pressure pulsation by optimizing the layout of fuel pipes. Our simulation results agreed well with our experimental results.

A totally integrated vehicle electronic control system is described, which optimizes vehicle performance through use of electronics. The system implements efficient coordination of functions of the engine, drive-train, brakes, steering, and suspension control subsystems to give a smoother ride, better handling and greater safety. The principles of the system are based on control and stability augmentation strategies. Each subsystem has two observers which control the force of the actuators according to the vehicle dynamics. The system features a driver support system which allows the average driver to employ the full performance potential of the vehicle in exceptional situations, and an artificial response control system to ensure optimum response and comfort. Application of the system allows the driver to experience a new level of performance and a marked improvement in handling quality and ride comfort.

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.

The concept of a “controller grid”, which makes effective use of computational resources distributed on a network while guaranteeing real-time operation, is proposed and applied to realize highly advanced control. It facilitates the total optimization of a plant control and achieves the high efficiency that is not acquired by individual plant optimization. To realize this concept, migration of a control task customized to be executed on one particular microcontroller to another microcontroller is necessary while strictly observing the required response time. Two techniques to meet this requirement are proposed: “task migration” for a control system and “real-time guaranteed scheduling of task migration and execution”. The effectiveness of the controller grid is assessed by applying it in experiments with electronic-throttle-body (ETB) advanced control.

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.