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To study the effects of various parameters on the fuel distributions, planar laser induced fluorescence(PLIF) was applied to an operating engine. Particularly, the effect of an air-shroud injector was investigated in the cold condition. Iso-octane was used as the fuel and gasoline(10%) was added as a fluorescing tracer. The fuel distributions during the whole processes of intake and compression were investigated at firing condition and analyzed qualitatively. In addition, flame images were acquired to understand the combustion characteristics. In cold and fuel injection during intake valve closed conditions(IVC), a number of fuel droplets flowed into the combustion chamber in the early and middle stage of intake process and the sizes of droplets were smaller than several tens of μm at both injectors; regular dual stream(D/S) and air-shrouded(A/S). Considerable amount of droplets remained until the late stage of the compression process.

Steady state experiments on a single cylinder spark ignition engine were performed to investigate the effects of compression ratio on nitric oxide and hydrocarbon emissions using natural gas as the fuel. Compression ratios between 8 and 15 were investigated. Constant throttle tests were performed at different equivalence ratios, throttle openings and spark timing settings covering a wide range of these parameters. In general, nitric oxide and hydrocarbon emissions were found to increase with compression ratio at fixed spark timing. With optimised (MBT) spark timing, however, reductions of emissions could be achieved at high compression ratio. This indicates that a fully optimised natural gas fuelled engine may be able to achieve high efficiency and low emissions.

Knocking phenomenon in a spark ignition engine breaks out due to autoignition in the unburned gas region. Investigation on the pre-autoignition reaction, that is, the reaction of cool and blue flames happening before autoignition must be carried out in detail to control knocking. The reactions appear in an extremely short time before autoignition, so, much difficulties accompany an attempt to grasp the situation. In the experiments presented hear, progress situation of pre-autoignition reaction was made clear by visualized phenomena in a rapid compression and expansion machine (R.C.E.M), which had good reproducibility. Taken by two ultra high-speed video cameras. We determined the ignition delay time was caught by analyzing the emission of light from the combustion chamber before knocking occurrence.

This paper presents a new transient passenger thermal comfort model. The model uses as inputs the vehicle environmental variables: air temperature, air velocity, relative humidity and mean radiant temperature all of which can vary as a function of time and space. The model also uses as inputs the clothing level and the initial physiological state of the body. The model then predicts as a function of time the physiological state of the body and an effective human thermal sensation response (e.g. cold, comfort, hot, etc.). The advantage of this model is that it can accurately predict the human thermal sensation response during transient vehicle warm-up and cooldown conditions. It also allows design engineers the ability to conduct parametric studies of climate control systems before hardware is available. Here we present the basis of the new thermal comfort model and its predictions for transient warm-up and cooldown conditions.

The present study shows how the application of computational fluid dynamics can help to understand and optimize the flow field in a passenger compartment in order to achieve an optimum of thermal comfort for the occupants. The flow field and temperature distribution in a passenger compartment have been calculated using the commercial CFD program STAR-CD. In combination with a thermophysiological model for the passengers, the computational results are used to evaluate the thermal comfort of the occupants and compare different geometrical modifications. The computational mesh consisting of around 3 millions hexahedra cells resolves all geometrical details of the car cabin including the air ducts, air nozzles and louvers. Natural convection, heat conduction and radiation are taken into account. One standard climatisation mode, the winter heat-up mode has been simulated. A special emphasis of the numerical investigations is the optimization of the ventilation of the front and rear legroom.

This paper is dedicated to a complete car cabin model for climate control and the expected experimental validation based on a comparison between wind tunnel tests and calculation results. Climate control system developments have to be improved in terms of time and quality by introducing calculation tools during project phases. This approach is related to some others presented the last two years (SAE papers Nos. 950019, 960813, 960961). SAE papers No. 960961 specifically presented a new meshing tool for car cabin geometry and its place in HVAC system development. In addition to this unusual, but powerful method of meshing, a new calculation tool «ACOZ» (flow, convection, conduction and radiations) has to be validated before being used in a real project. This validation is composed of three major parts. The first part is the meshing work based on a CAD-CATIA file treated with «Maille» through IGES transfert, with its major functionality (anamorphic stretching).

In the context of LEV and ULEV, and to improve performances and passenger comfort, the closed loop optimisation of the engine torque is one of the major element of the engine control strategy. To do that, the knowledge of instantaneous engine torque is needed. In this paper, we are looking for economical and reliable methods to estimate the average indicated torque (of each cylinder) during its combustion stroke based on crankangle measurements. These methods use an engine model which must be both simple for ‘on line’ implementation and accurate enough for a good estimation. We will be presenting and discussing the assumptions and the requirement to meet for this determination.

Improvements in several areas are required to convert current technology light-duty vehicles into low-emissions vehicles suitable for meeting California's Ultra-Low Emissions Vehicle (ULEV) standards. This paper discusses one of those areas, the engine and aftertreatment control system algorithms. The approach was to use model-based air and fuel flow calculations to maintain accurate air-fuel ratio control, and to interface the aftertreatment requirements with engine air-fuel ratio control during the cold- and hot-start parts of the cycle. This approach was applied to a 1993 Ford Taurus operating on Ed85 (85% denatured alcohol, 15% gasoline).

Due to the present demand for further improved emissions and performance of diesel engines, there is a growing need to improve the control of fuel injection quantity and timing, as well as spray properties. We have developed a Micro Turbine Sensor that can measure transient injection rate and timing using micro machining technology. This sensor realizes volumetric flow measurement using a tangential turbine as the sensing element which has an outside diameter of 1mm, and which is located next to the inlet connector of the injection nozzle. The measured results are compared with a Bosch type injection rate meter. Since the tendency of measured injection rate shows fair agreement with results of the reference system, this sensor has potential as a fuel flow meter which is able to measure the injection rate and timing directly and continuously during engine operation.

This paper deals with the supervision of the Diesel injection process. A new method to analyse the injection quality is presented which is based on the acquisition and evaluation of cylinder pressure signals. In this novel approach, a reconstructed “motored” pressure is substracted from the fired pressure signal resulting in independence from a possible sensor offset and a contrast amplification. To describe the shape of the difference pressure, features like the center of gravity or the secant length at certain pressure values are introduced. These numbers can be used for supervison of the injection pump (backward diagnosis) as well as for driving the engine at operating points with low exhaust production (feedforward control). The presented concept is supported by simulations and real-time measurements obtained from a swirl chamber Turbo Diesel stock car engine (4 cylinders, 1600 ccm).

A single point turning test method for establishing a generalized machinability database for bar steels is proposed by the Bar Application Group of the American Iron and Steel Institute. A unique aspect of this work is the large number of participants including steel companies, steel users, machining laboratories, and a tool manufacturer. The proposed test methodology to evaluate steel machinability, based on ISO 3685, is outlined. Variability in tool life data has been evaluated through a controlled round-robin test program for three steel grades: SAE1141, SAE1541, and SAE4140. Major factors contributing to variability in tool life studies include (1) machine dynamics, (2) tool wear measurement methods, and (3) premature tool failure prior to reaching a specified wear criterion. After addressing these factors, it is felt that the proposed test method can provide adequate single point turning test results to aid in the material selection process.

The relative machinability of four low carbon, resulfurized, rephosphorized free cutting steels (1215, 12L14, 1214+0.1wt%Bi & 1214+0.2wt%Bi) were evaluated using a modified ASTM E618 machine form tool wear test. The chemical, mechanical and micro-structural characteristics of these four steels are compared and correlated to the machining performance. The 1215 consistently survived 8 hours machining at 77.4m/min (meters/minute)[(254sfpm (surface feet per minute)] and 4 of 6 tests passed 8 hours at 85.3m/min (280sfpm). The 12L14 survived 8 hours at 85.3m/min (280sfpm), but consistently failed the test at 95.1m/min (312sfpm). The 1214+0.1wt%Bi consistently survived 8 hours at 95.1m/min (312sfpm), but failed at 111m/min (364sfpm). The 1214+0.2wt%Bi also survived 8 hours at 95.1m/min (312sfpm) and one of six tests passed 8 hours at 111m/min (364sfpm). At each test speed the rough form tool and finish form tool generated surface roughness (Ra) was monitored.

In today's competitive efforts to continuously improve both material performance and quality, the “designer team” of laboratory scientists and engineers, manufacturing engineers, and marketing specialists must consider the ultimate cost of manufacturing at the very beginning of new product development. One method of controlling costs is by manufacturing new materials using continuous processing methods versus batch processing methods. Although continuous processing is not new to manufacturing, developing high performance material systems adaptable to such methods is still a challenge for chemists and engineers. This paper describes current R & D work to develop gasket materials which can be manufactured by continuous coating or continuous lamination of coiled substrates, e.g., metals, dense papers, etc. The focus of the paper is a discussion of work to relate material properties and performance to chemical structure of the gasket materials.

In an integrated noise isolation system, both gasket and bolt isolators play an important role in the resultant total load, contact stress, and system static and dynamic stiffness. One standard approach to design is based on using a shape factor in conjunction with a simple stress-strain relation. This approach can produce reasonable results under small deformation. But the deviation is so large that it is not appropriate to use it for reliable designs under large deformation. Experimental approaches and finite element methods are effective at characterizing the load-deflection relationship of bolt isolators under large compressive deformation. In this paper, a parameter study of a sequence of finite element analyses will be presented and a parametric model will be determined based on the FEA results to best represent the isolator load-deflection behavior under large compression.

The response of a gasketed, bolted joint to an external load is understood to be effected by all components involved in the joint. The analysis involves the equilibrium of the gasket compressive force with the bolt tension force and the forces external to the bolted joint. Geometric compatibility is maintained when the change in the stretch of the bolt caused by an external force is equal to the change in compressed thickness of the gasket. When the flanges are treated as nondeformable, the classical joint diagram analysis indicates that externally applied loads, which unload the gasket, increase bolt tension. In this paper, the effect of flexible flanges is included in the analysis of simple gasketed bolted flanges. The results show that bolt tension response can deviate significantly from the rigid flange behavior. In certain situations where flanges have a relatively high level of flexibility, external joint forces that unload the gasket also unload the bolt.

A proprietary refrigerant, called Ikon®-12, was evaluated as an alternative to HFC (hydrofluorocarbon)-134a for automotive air conditioning. The evaluation was motivated by concern over the relatively high global warming potential of HFC-134a. In preliminary tests. Ikon®-12 was found to be compatible with a polyolester lubricant and engineering materials. Refrigeration capacity and efficiency for Ikon®-12 compared favorably to those for HFC-134a. In a preliminary durability test, Ikon®-12 refrigerant showed no significant chemical breakdown after extended operation with an elevated compressor discharge temperature. Further testing would be required to determine if stability and materials compatibility are acceptable for long-term use.

There is intense research activity to appraise the merits of the carbon dioxide (R-744) mobile air conditioning system due to its perceived amelioratory effect on the total global warming impact which comprises two components: direct global warming due to refrigerant leakage into the atmosphere and indirect global warming due to power consumption by the system. While the direct global warming impact of R-744 is negligible compared to that of R-134a, the indirect global warming impact of the R-744 system is intrinsically higher than that of the R-134a system. In order to quantify the indirect global warming impact of the R-744 system, an accurate assessment of its coefficient of performance (COP) vis-a-vis COP of the present baseline R-134a system is necessary.

This paper describes the transient spray characteristics of a high pressure, single fluid injector, intended for use in a direct-injection spark-ignited (DISI) engine. The injector was a single hole, pintle type injector and was electronically controlled. A variety of measurement diagnostics, including full-field imaging and line-of-sight diffraction based particle sizing were employed for spray characterization. Transient patternator measurements were also performed to obtain temporally resolved average mass flux distributions. Particle size and obscuration measurements were performed at three locations in the spray and at three injection pressures: 3.45 MPa (500 psi), 4.83 Mpa (700 psi), and 6.21 MPa (900 psi). Results of the spray imaging experiments indicated that the spray shapes varied with time after the start of injection and contained a leading mass, or slug along the center line of the spray.

Very high data rate Phase Doppler Measurements were carried out in order to demonstrate the spray characteristics at each cycle and how each injection differed from each other. Conventional time-averaged data analysis can hardly provide information to analysis cyclic variation of spray formation and droplet dynamics so that a cycle-resolved PDA system was developed in the study. A direct gasoline injector for two-stroke marine engine was used for the experiment. For data analysis, droplet dynamics and characteristics of different droplet diameter were examined. The results show mat cycle variation of injector was remarkable, the maximum spray tip velocity differed from 63 m/s to 93 m/s even for the consecutive injection. The data rate obtained was over 40 kHz (Max: 85 kHz) and bin width was carefully examined to show the spray collision to air and entrained air motion.

The principle strategy, the development emphasis, and the investigation parameters of a DI gasoline engine are discussed. Several different combustion systems are briefly described and one system where the spark plug is located near the fuel injector is investigated. In addition, the influence of different operating parameters are studied. Some reasons for the improvement in the efficiency of a DI gasoline engine are shown with the help of thermodynamic analysis and simulation calculations. These show that at a constant operating point (engine speed = 2000 rpm, bmep = 2 bar) there is a reduction of the fuel consumption of 23% at unthrottled conditions in comparison to the homogeneous stoichiometric operation. In particular, the reduction of the pumping and heat losses and the reduction of the exhaust gas energy are responsible for this fuel consumption reduction.