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A new alumina ceramic substrate has been developed for an Electronic Control Unit (ECU). This substrate has a thick conductor circuit made of molybdenum for a power line, accepting high electric current up to 50 Amperes (standard design). The design concept can integrate control and power circuits in one substrate, directly mountable on engines or power train system without any forced cooling system. Cross-sectional shape of the conductor is designed to minimize thermal stress and reduce cracking in the substrate, caused by a thermal expansion mismatch between alumina and molybdenum. Optimization of the design is performed by FEM analyses and X-ray diffraction measurement. We confirmed that the substrate can work after 10,000 cycles of temperature cycle test, and 600,000 cycles of electric cycle test.

Gasoline engine control continues to become more sophisticated and so the amount of software has reached 10 to 20 times that of early control systems. By changing the embedded microcomputer from 8bit CISC (Complex Instruction Set Computer) to 32bit RISC (Reduced Instruction Set Computer), processing performance has been improved 100 times. This paper evaluates quantitative performance of the RISC CPU having a FPU (Floating Point Processing Unit) and describes an example application to adaptive control.

A new intelligent IGBT for auto motive ignition system with a precise and stable constant current limiting circuit has been shown to operate at a constant current of 11±1.0 A between -40°C and +150°C. The new IGBT also has a stable clamping voltage of 410±10 V between -40°C and +150°C, a logic level driving gate voltage of 5±1 V, and a large unclamped inductive switching (UIS) energy of 350mJ at +150°C.

The paper deals with potential augmentation of the present R134a automotive air conditioning system with the intent to lower its total equivalent warming impact (TEWI) which is a source of concern from the standpoint of environmental benignity of the system. It is identified that the most effective augmentation strategy includes (1) increase in compressor isentropic efficiency, (2) increase in condenser effectiveness, (3) decrease in lubricant circulation through the system, (4) decrease in air side pressure drop in evaporator through improved condensate management, (5) increase in condenser airflow, (6) decrease in air conditioning load via permissible increase in the amount of recirculated air through the passenger compartment and (7) reduction in direct emission of R-134a from the system through conservation and containment measures. The effect of each of these augmentations on the coefficient of performance (COP) of the system is quantified in a rigorous fashion.

Carbon dioxide (CO2)-based refrigeration systems have been proposed as environmentally benign alternatives to current automotive air conditioners. The CO2 vapor-compression system requires very high operating pressures and complicated control strategies. Recent experimental results indicate that operating pressures comparable to those of current automotive air conditioners can be attained by the inclusion of a secondary carrier fluid (a “co-fluid”), with solution and desolution of the CO2 from the co-fluid substituting for condensation and vaporization of pure CO2. In this work, modeling tools have been developed to optimize the CO2/co-fluid cycle, including the selection of a co-fluid, the CO2/co-fluid ratio (the “loading”), and the operating conditions.

Environmental concerns have spawned renewed interest in naturally occurring refrigerants such as carbon dioxide. CO2 has attractive features such as high enthalpy of evaporation and low cost compared to halocarbons. However, the vapor pressure of CO2 is high at temperatures normally encountered in refrigeration and air conditioning systems when compared to traditional and alternative refrigerants such as CFC-12 and HFC-134a. Major research efforts are underway to investigate the transcritical CO2 cycle, in which a gas cooler instead of a condenser accomplishes heat rejection to ambient, since carbon dioxide under these conditions is above the critical point. The vapor pressure in the gas cooler may exceed 120 bar (1,740 lb/in2). In this paper a reduced pressure carbon dioxide system is reported (Ref 1). Two companion papers will address properties of working fluids (Ref 2) and thermodynamic and cycle models (Ref 3) for the low pressure carbon dioxide cycle.

Due to a surge of public interest in environmental conservation in recent years, the automobile industry now faces technological innovations to provide environmentally friendly engines. Among these engines, direct injection engines have become the primary candidates for use in the near future due to their lower fuel consumption and CO2 emission in comparison with conventional uniform charge combustion engines. Innovative technologies of these engines demand that the air conditioning system be of “a power saving design” and “compatible with the engine.” In these new requirements, the variable displacement compressor is more advantageous than other types, which will be shown in this paper. The paper will also explain the mechanism that can bring a larger fuel saving effect through “optimal control” of a variable displacement compressor by its external control.

Next to air temperature, humidity, and air quality, it is sound emission that exerts a significant impact on the driver's and passenger's comfort. Major progress in vehicle acoustics has motivated vehicle manufacturers and systems suppliers to evaluate HVAC systems no longer by their air conditioning performance alone. Sound emissions and sound quality have become additional important criteria for the development of new HVAC systems. In the initial conception phase, where systems and packaging considerations are made, acoustic optimization must begin with preliminary system studies and feasibility studies. In this phase acoustics should be based on fairly general systems specifications which describe the desired degree of acoustic comfort. In the subsequent design phase follows the specification of the acoustic goals and the optimization of the HVAC unit. Detailed analysis and optimization of air flow and blower are the common targets for improvement at this time.

In recent years, Global Warming Potential (GWP) has become as important as Ozone Depletion Potential (ODP) when evaluating a potential refrigerant. Increasing concern over GWP of HFC-134a and its effect on the environment have led international heating, ventilation and air conditioning, and refrigeration (HVAC & R) industries to look at other options. This study documents an assessment of some of the options. It describes simulated performance of R152a and hydrocarbon refrigerants and their potential as alternative refrigerants to HFC-134a in mobile air conditioning systems. In addition, a comparative assessment of the performance of a secondary loop system using these refrigerants is provided.

This paper describes the performance of a transcritical R744 a/c system for a typical compact car. The prototype was designed to have heat exchanger dimensions, face velocities and air-side pressure drops nearly identical to conventional R134a systems. Heat exchangers are made of flat aluminum extruded multiport tubes; the 21 cc compressor is of swash plate design, and the system can be controlled by either a needle valve or a backpressure valve. Test matrices are defined for the purpose of developing component and system simulation models, as well as supporting data-to-data comparisons at normal, seasonal and extreme operating conditions. The design of experiments and test facility are also discussed. Results are presented for the R744 system operating in both steady state and cycling modes.

Refrigerant charge and internal volume of the components have influence on the performance and reliability of an Air Conditioning system. A low refrigerant charge can create problems to the compressor for an improper lubrication of its parts, while an excess of refrigerant charge can increase the condensation pressure substantially with negative effects on the air temperature at the dashboard. Internal volume of the A/C components influences the refrigerant optimum charge, and among these the internal volume of the Receiver has a sensible impact on the refrigerant charge. Lower refrigerant charge is in addition the general demand of car makers both for cost reduction and for environmental reasons (less refrigerant lost in the atmosphere per car in case of car accident or leakage). The purpose of the paper is to present the results of experimental analysis on the influence of the refrigerant charge and receiver capacity on the performance of an A/C systems.

The paper shows how processing parameters of an injection transfer-moulding machine can be controlled to create and identify moulding faults of valve-stem seals. By controlling the processing parameters to produce typical valve-stem seal moulding faults at the system design stage, causes for waste can be identified. Detailed knowledge of the manufacturing process is fed into a knowledge based SPC quality system to monitor and control the manufacturing process. This information is used in the manufacture of valve-stem seals to improve quality and reduce waste.

Regarding a rubber seal used between a cylinder head cover and a sparking plug tube of an automobile, the author couldn't calculate escape load of the rubber seal in the head cover casing, because rubber friction coefficient and Young's modulus on the escape load was unknown. The effect of the measurement method of rubber friction coefficient and Young's modulus on the escape load, and method of measuring this escape load will be described in this report.

In order to clarify the sealing mechanism of radial lip seals, a new test apparatus with a hollow glass shaft was developed, and the fluid behavior under sealing condition was observed by using the Laser Induced Fluorescent (LIF) method. In this paper, the description of the test apparatus and first measurement results are shown. A laser dye dissolved in synthetic oil below the seal lip was excited at a wavelength of 427nm by a SHG solid state blue light laser. The fluorescence was detected by a CCD camera through an optical filter. The fluid paths of the oil beneath the seal lip appeared ahead of each rib as soon as a shaft started to rotate. Furthermore, the intensity of the fluorescence, which is related to the fluid film thickness, increased with shaft speed increasing. First measurement results obtained with the LIF method were in good agreement with other measurement results.

The world's first continuous running, externally controlled, variable displacement compressor for automotive applications has been developed(6SE12 with DL-Pulley). This compressor design is based on a conventional swash plate internally controlled variable displacement compressor and has an integrated solenoid valve which controls displacement compressor by receiving an external electrical signal. It enables the development of a power saving system running at optimum conditions. The compressor was developed as a continuos running type by improving the component parts from a reliability standpoint. As a result, a new DL-pulley(Damping & Limiting) could be developed which has a more simple structure than conventional magnetic clutches. Therefore, the 6SE12 with DL-Pulley can reduce vehicle fuel consumption and improve the ease of installation into the engine compartment.

The catalytic performance and On-Board Diagnostics (OBD) of the manifold catalyst having high Oxygen Storage Capacity (OSC) are described in this paper. First of all, we compared the performance of three-way catalysts containing Cerium - Zirconium - Yttrium oxide with Cerium - Zirconium oxide. Three-way catalysts dispersed Pt, Rh and Pd on Cerium - Zirconium - Yttrium oxide showed excellent catalytic performance especially at cold starting and at transient states, after high temperature aging at 1050°C. The performance of these catalysts was studied using the Driving Mode Simulation Dynamometer, which was developed in-house, and oxygen storage and release responses were compared in actual gas. Then we investigated the possibility of on-board diagnostics of catalyst deactivation with high OSC in manifold and close-coupled positions, a diagnostic which is usually assumed to be difficult to attain with present conventional technology.

The European driving cycle, deleting the first 40 seconds of idle after the start up phase, and the US FTP 75 cycle are compared in this paper. The paper presents an analysis of emission tests for CO, HC and NOx measured during tests performed on a chassis dynamometer under laboratory conditions. The tests are reviewed and the results discussed. The objective of the study was to determine the influence of the test cycle on the measured emission of CO, HC and NOx, and the changes of fuel consumption at the initial phase of engine operation. Differences in catalyst warm up rates when running NEDC, ECE + EUDC and FTP 75 cycles are demonstrated. Methods of reduction in these harmful emissions and the results of tests with new technologies targeted at the reduction of CO, HC and NOx under cold start are also discussed.

The paper reviews the relationship between CO2 emissions and fuel consumption in a range of automobiles presented for type approval over the last two years. The procedures used in the examination for approval in the presented scope have been described and several results of these examinations conducted in Poland in accordance with the requirements of the Regulations no.101 ECE UNO (Directive 93/116 EC) are evaluated. The evaluation of the possibilities of fulfilling the existing and future requirements of the above mentioned CO2 emissions are discussed.

Deployment of an airbag or charging of a tank by an inflator-canister system is a highly dynamic process. Quantification of energy storage, energy flux, work done, flow rates, thermodynamic properties, and energy conservation are essential to describe the deployment process. The concepts of available work and entropy production are presented as useful parameters when evaluating airbag aggressivity from tank test results for different types of inflators. This paper presents a computational methodology to simulate a pyro- and a hybrid-inflator-canister-airbag system to predict the force pattern that could occur on an out-of-position occupant when the airbag deploys. Comparisons with experimental data have been made in all cases where data were available. These include driver-, passenger-, and side-airbag designs.

A new fast combustion inflator based on the reactions of methane-oxygen mixtures has been developed. The performance of this inflator was evaluated in terms of pressure-time relationships inside the inflator and in a receiving tank simulating an air bag and by assessing the temperature-time relationship in the tank. In order to develop this inflator, several critical issues were studied, including stoichiometry, initial mixture pressure and extreme ambient conditions. Other design parameters such as burst disk thickness and type, ignition device, tank purging gas, concentration of carbon monoxide, severity of temperature in the tank, and the inflator size were investigated and optimized. To simulate the behavior of this inflator, a theoretical and integrated model was developed. The experimental results made at different conditions were found to be in agreement with the model.