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Automotive manufacturers are working towards protecting the global environment by using filters to reduce particulate matter (PM) emissions from their vehicles. There is a growing demand for sensors that detect the small amounts of PM leaking through these filters, as they can aid in performing on-board diagnostics (OBD) and monitoring the function of these filters. Currently, vehicles predominantly use an electric resistance type PM sensor, which applies a voltage between electrodes, collects PM, and senses the generation of PM path. However, in response to tightening regulations on PM-OBD, the response time of the sensor needs to be optimized. Furthermore, the fast response time must not degrade the poisoning resistance in order to ensure durability. To shorten sensor response time, we have developed a 20 μm-gap electrode structure using a cross-section of laminated alumina sheets with printed electrodes, which can form PM paths at small PM amounts.

There has recently been an increasing need in various automotive monitoring and control systems for a simply structured and highly reliable high-pressure sensor to detect the higher pressures of oils, hydraulic fluids, air and air conditioning refrigerants. A simple, newly devised approach to sealing oil filled high-pressure sensors is introduced in this paper. The new structure utilizes a resin instead of the metal and glass conventionally used for hermetic sealing oil filled high-pressure sensors. This is made possible by the combined use of oils with large effective molecular diameters and carefully optimized design of shape and size of the sealing faces between sensor parts. The use of a sealed metal diaphragm allows for extensive use of the sensor with many different kinds of pressure media and in various applications.

Many ICs are used in various electronic components in automotive applications, such as ECUs (electronic control units) and smart actuators. Automotive ICs required the following features: (1) high integration of analog, digital and output devices; (2) high breakdown voltage for analog devices standing the battery voltage; (3) highly accurate control for analog circuits; (4) susceptibility under harsh operating conditions, such as high ambient temperature and high humidity; and (5) high surge immunity such as ESD (electrostatic discharge) robustness. To meet these requirements, we developed analog and output devices with improved surge endurance based on SOI wafer and trench-dielectric-isolation technologies. Analog circuit applications, especially accurate power management or high-precision solenoid driving, demands stable temperature-compensated output. Load dump and battery-jumping also needs high voltage protection and high noise immunity for these devices.

In Japan, from the viewpoint of ozone layer protection, specified CFCs (Chlorofluorocarbons) phase-out started in 1992 and completed by 1995. HFC-134a (Hydro fluorocarbon-134a) is now dominant in the market. HFC-134a, the replacement, has zero ozone depleting potential, while it still has a higher global warming potential (GWP = 1430). In this paper, efforts of DENSO and the Japanese industry from aspects of refrigerant emission reduction and energy efficiency improvement are introduced.

Customers tend to require more comfortable climate control in vehicles. This paper is concern with a new infrared sensor that detects surface temperature at six separate locations, and a climate control system that incorporates the sensor. In a conventional system using an air temperature sensor and solar radiation sensor, climate conditions are usually controlled according to the thermal load. It is believed that more comfortable climate control can be realized by using an infrared sensor to detect passengers' surface temperature. The sensor consists of a lens, an IC with six thermopiles, a circuit and a case, and has been improved to detect in-cabin surface temperature accurately even under severe environmental conditions. The HVAC system controls the outlet air temperature and mode individually for each seat according to detected temperatures.

We have developed a novel wafer process for capacitive sensing accelerometer using surface Micro Electrical Mechanical Systems (MEMS) technology and successfully applied to the fabrication process. Our new process combines with a single crystal SOI (Si on Insulator) wafer, high aspect ratio silicon etching and newly developed anhydrous HF/Alcohol etch process of silicon oxides. Although wet conditions such as HF/water etch occurs stiction of mobile structure, our anhydrous HF/Alcohol etch process technology occurs no stiction of mobile structures, because of gas phase (dry) process. In our process, we have achieved smaller-sized sensor chip compared to our conventional 2 axes accelerometer.

Increased interest in global warming issues requires rapid improvements in reduction of CO2 emissions. The automotive industry is placing high importance on improving fuel economy performance across their entire product lines. Charging Management System is a necessary element towards fuel economy improvement. Many of today's charging management systems perform at least two important functions: improving efficiency based on vehicle motion, and detecting battery state of charge. These systems become more complicated as more components (i.e. generators, current sensors and ECU) and software are added. Therefore, it is difficult to develop charging management systems for an entire product line and difficult to retrofit the system for vehicles already in production. A stand-alone charging management system solves these issues. This system is independent of the other vehicle systems. The software for improving fuel economy is installed in the generator or current sensor.

Increasing electric loads in a vehicle causes over-discharge of a battery and drag torque due to an alternator. This paper gives a system concept of vehicle electric power flow management to solve these issues. Its primary function includes preserving electricity in a battery, stabilizing electric bus voltage, interfacing with vehicle torque control system, and improving fuel economy. The key point to realize such a system is a unified structure. It offers ‘Plug and Play’ function for electric power management components. Newly developed Vehicle Electric Power Flow Management System (VEF ) totally controls electric power flow in a vehicle. VEF contains an Electric Power Manager and its functional sub-systems, and controls them with the key parameter ‘electric power’. The sub-system includes Generation, Storage, Conversion, and Distribution to the loads.

Up to now, while automobile electric packages have demanded the high density for small and light products, electric leaks, which have occurred due to condensation, have been a major problem. To prevent any electric leaks, a conformal coating on the electric parts (ex. ECU: Electronic Control Unit) has been needed, but in general the design rules of the conformal coating (ex. Application area) is vague. Therefore, DENSO demands to clear the design rules of conformal coating electric package for higher reliability. To meet the demand, DENSO has developed a condensation simulation method using CAE that can show the occurrence condition of condensation fast and accurately. In the result, DENSO has been able to get the design rules where to need the conformal coating in the electric package for automobiles.

In 1997, we have applied laser technology to the world's first practical adaptive cruise control (ACC) system. The ACC system is based on 2-dimensional scanning laser-radar-sensor technology that is supported by highly reliable high power diode laser. Now, we have developed 34W output power multiple-quantum-well (MQW) diode laser. The power of 870nm near IR diode laser is twice as high as conventional one, thus it meets the strong needs for robust detection of the reflective laser beams from the moving vehicle ahead. Furthermore, Au-Sn-Ni a new alloy solder has been employed to sustain high degree of vibration and thermal shock to raise reliability. The acceleration life-tests at high temperature pulsed operation demonstrate the high reliability of developed 34W high power diode laser.

Spark plugs with higher ignitability are continuously in great demand to realize high fuel efficiency and low emissions. To meet this demand, DENSO launched the Iridium Spark Plug in 1997, which realized the two characteristics that had been conventionally difficult to achieve concurrently-high ignitability and long life. The development of this product was enabled by miniaturizing the center electrode, produced using DENSO's original, highly wear-resistant iridium alloy (featuring a high melting point and excellent oxidation resistance). While spark plugs are now required to have a longer service life, they are also required to be higher in ignitability, as exhaust gas regulations have been tightened recently. However, the effort to miniaturize the center electrode is reaching a limit.

Carbon brushes for automotive starters are used under severe conditions of high electric current density, high contact pressure and high sliding velocity. Therefore lead has traditionally been added to brushes to improve performance and durability. Lead is an environmental hazardous substance. In the EU, the law prohibits adding lead to brushes for electric motors which is installed on new automobiles in and after January 2005. In order to develop the lead free carbon brush for starters, we analyzed the effect and selected substitutive substance of lead. Adding lead to the brush reduces the electric resistance increase of the brush in high-temperature and high-humidity atmosphere and in high-temperature atmosphere. Furthermore lead reduces the wear amount of brush. We developed the lead free brush surpassing the lead addition brush in performance and durability by addition of lead alternatives silver and zinc.

We propose a novel millimeter wave radar system and object detection algorithm for automobile use by using advanced null scanning method. Generally, null scanning method can achieve a higher resolution and a more compact sensor size compared to beam scanning method, but needs huge computing power. We introduced the theory of forgetting factor into it and developed a new null scan algorithm. It achieved a high lateral object separation ability of less than 3 degree, and a quick response under feasible computing power in simulation and test vehicle. These technologies enable compact and high performance radar for advanced safety system.

We have developed a novel capacitive acceleration sensor fabrication process by applying surface MEMS (Micro Electro-Mechanical System) technology and successfully introduced this process for volume production of a new super slim sensor. The new process uses the ICP-RIE(Inductively Coupled Plasma - Reactive Ion Etching) technology to etch single crystal SOI(Si on Insulator wafers. In this technology, vertical Si etching is followed by, lateral etching along the buried oxide to release the movable electrode. Because of a dry process, the new process does not cause the movable structures to stick to each other. Our process uses only three masks and reduces the sensor chip size to a half that of our conventional capacitive acceleration sensors.

A lot of electric components have been installed in a vehicle today for comfort, safety and environment. This tendency is said to be continued in the future. Therefore, additional power supplies such as exhaust gas electricity generation system and thermal electricity generation system have been developed in the world to supply additional electricity as well as an enlargement of an alternator. However, if these new electricity supply systems are installed in a present electric power system that is controlled based on a voltage feedback, each supply system cannot be controlled effectively, because it is difficult to control output power of each system independently. An electric power based control system, Vehicle Electric power Flow management system (VEF), has been developed to avoid this problem. Sum of required electric power is calculated based on electric loads power and battery charging power. This required power is allocated to each power supply system.

In an effort to protect the earth's environment, emission regulations in the diesel engine field are becoming increasingly strict. One way of meeting these regulations is to atomize the fuel spray by using a fuel injection system with high-pressure injection, which activates engine combustion. With current in-line pump systems, however, it is still possible to satisfy the demand for cleaner emissions by improving the fuel spray, through measures such as reviewing high-pressure injection and initiating improvements in the nozzle. This report describes the new in-line pump system for medium duty diesel engines to meet future emission regulations. In this report, we will describe how analytical technology, such as computer simulation, was used on the pump side to make improvements for higher injection pressure.

The lateral DMOS (LDMOS) had been developed for intelligent power IC[1][2] for ECU (Electric Control Unit). The process and device simulation methodology are used while developing a devices. The physical model and parameter in analytical model are calibrated to enhance the accuracy of the simulation and to reduce lead time and costs.

The challenge for the diesel engines today is to reduce harmful emissions, such as particulate matter (PM) and Nitrogen oxides (NOx), and enhance the fuel efficiency and power, which are its main advantages. To meet this challenge, DENSO has developed an advanced common rail system (CRS) that uses piezo actuated fuel injectors capable of delivering up to five injection events per combustion cycle at 180MPa, currently the world's highest commercially available diesel fuel injection pressure. The DENSO piezo injector incorporates an internally developed piezoelectric element that energizes quicker than its solenoid counterpart, thereby reducing the transition time for the start and end of the fuel injection event. The piezoelectric element and unique passage structure of the DENSO injector combine to provide a highly reliable and responsive fuel injection event.

There is increasing demand for a finer atomization of fuel spray in order to improve the engine performance and mileage, reduce exhaust emissions and then improve the transient response. [1]. We are improving the shape of holes in order to enhance finer atomization. It is especially important to reveal the spray break-up process and droplet diameter quantitatively for a better development of holes shape. In this paper, we set our focus on a multiple-hole nozzle and developed a quantitative visible analysis method to investigate the spray break-up process and droplet diameter. With this method, index of the relationship between break-up process and droplet diameter was defined. And by re-shaping the holes and by arrangement of the holes, the break-up process and droplets diameter were investigated.

A recent trend in the making of automotive engines, where high efficiency and low emissions need to be considered, is to mount multiple parts around the motor in order to improve overall engine efficiency. As a result of modern technology, the engine head and surrounding space have an excessive amount of parts. To accommodate the congested engine compartment, it is desirable to reduce the size of the spark plug. Small size spark plugs have the problem of poor resistance to carbon fouling and are subject to side sparks if carbon fouling occurs. This results from a reduced insulating gap between the center electrode and the housing achieved by reducing the size of the spark plug. By using visualization of flame growth and electric field strength analysis, we have conducted studies on insulator temperatures and spark behaviors in search of the optimal specifications.