High Load Region Research Articles

21106 成層化によるHCCI機関の燃焼特性の研究(燃料と燃焼の新しい展開(2),OS.9 燃料と燃焼の新しい展開,学術講演)

Homogeneous Charge Compression Ignition (HCCI) combustion has attracted considerable interest in recent years as a new combustion concept for internal combustion engines. The HCCI combustion process has four issues to be resolved: ignition timing control, slower combustion reaction rate (maximum heat release rate), difficulty expanding stable operation to the high load region and avoidance of knocking. In this study, an attempt was made to overcome these issues by mixture stratification. This stratification combustion has such a concept.: the density of the air-fuel mixture is uniform, the ignition characteristic is different in the cylinder. The experimental result that ignition occurred locally at the low octane side then occurred high octane side in the cylinder. As the result, the combustion reaction speed can be slower and avoidance of knocking without using EGR.

652 二種燃料成層化によるHCCI機関の燃焼特性に関する研究(応用熱工学III,オーガナイズドセッション)

Homogeneous Charge Compression Ignition (HCCI) combustion has attracted considerable interest in recent years as a new combustion concept for internal combustion engines. The HCCI combustion process has four issues to be resolved: ignition timing control, slower combustion reaction rate (maximum heat release rate), difficulty expanding stable operation to the high load region and avoidance of knocking. In this study, an attempt was made to overcome these issues by mixture stratification. This stratification combustion has such a concept. : the density of the air-fuel mixture is uniform, the ignition characteristic is different in the cylinder. The experimental result that ignition occurred locally at the low octane side then occuned high octane side in the cylinder. As the result, the combustion reaction speed can be slower and avoidance of knocking without using EGR.

Friction Characteristics of Poly(vinyl Alcohol) Hydrogel as an Articular Cartilage Biomaterial

Poly(vinyl alcohol) (PVA) hydrogel is a promising articular cartilage biomaterial. In this paper, the effects of different variable factors on the friction coefficient of Poly(vinyl alcohol) (PVA) hydrogel were investigated when sliding against stainless steel ball by ball-pan tribometer. Factors included lubrication condition, sliding speed, diameter of stainless steel ball, and load. It was shown that the free water in PVA hydrogel has an excellent lubrication on the counterparts. The friction coefficients have little difference between dry and lubricants lubrication condition at initial friction test. With the friction test time prolonged, friction coefficient of PVA hydrogel under dry condition increased rapidly. Friction coefficient decreased with the increase of sliding speed and the diameter of stainless steel ball, and increased with the increasing load. The rising rate of friction coefficient at low load region is obviously larger than that at high load region.

Complex impedance spectra analysis of SnO2-glaze composites

SnO2-glaze composites were prepared by Sb-doped SnO2 and SiO2−CaO−Al2O3−B2O3 glaze. The composites changed from an electrical insulator to a conductor as the SnO2 content increased from Owt% to 90 wt%. The complex impedance spectra of the fabricated composites were investigated in the frequency range of 100Hz-40 MHz and three kinds of typical shape of complex impedance spectra were recorded and analyzed. The spectrum is quite close to the model of conduction via nonohmic contacting when the SnO2 content is relatively low. In high loading region, the spectrum shows the conduction pattern through ohmic contact chains. In the moderate loading region, the model is a mixture of the above two models. Equivalent circuit of the composite changes from resistor-capacitor circuit to resistor-inductor circuit as the content of SnO2 increases.

4701 HCCI燃焼におけるオクタン価およびEGRの影響(S56-1 エンジン燃焼-さらなる進化を目指して-(1),S56 エンジン燃焼-さらなる進化を目指して-)

Homogeneous Charge Compression Ignition (HCCI) combustion has attracted considerable interest in recent years as a new combustion concept for internal combustion engines. The HCCI combustion process has four issues to be resolved: ignition timing control, slower combustion reaction rate (maximum heat release rate), difficulty expanding stable operation to the high load region and avoidance of knocking. In this study, an attempt was made to overcome these issues by applying internal exhaust gas recirculation (EGR). Internal EGR rates and octane numbers were varied and examined their respective influence on HCCI combustion.

Impedance spectra of carbon black filled high‐density polyethylene composites

AbstractCarbon black (CB) filled high‐density polyethylene (HDPE) composites are prepared by ordinary blending for use as an electrical conductive polymer composite. The composite changes from an electrical insulator to a conductor as the CB content is increased from 10 to 20 wt %, which is called the percolation region. For explanatory purposes, three models, namely, “conduction via nonohmic contacting chain,” “conduction via ohmic contacting chain,” and a mixture of them corresponding to the conductions in the percolation region, high CB loading region, and limiting high CB loading are proposed by the reasonable configurations of aggregate resistance, contact resistance, gap capacitance, and joining aggregates induction. The characters of the impedance spectra based on the three models are theoretically analyzed. In order to find some link between the electrical conductivity and the CB dispersion manner in the composites, the impedance spectra of three samples, HDPE/15 wt % CB (the center of the percolation region), HDPE/25 wt % CB (a typical point in the high CB loading region), and HDPE/19 wt % CB (the limiting high CB loading region), are measured by plotting the impedance modulus and phase angle against the frequency and by drawing the Cole–Cole circle of the imaginary part and real part of the impedance modulus of each sample. The modeled approached spectra and the spectra measured on the three samples are compared and the following results are found: the measured impedance spectrum of HDPE/15 wt % CB (percolation region) is quite close to the model of conduction via nonohmic contacting chain. The character of the measured spectrum of HDPE/25 wt % CB consists of the form of the model of conduction via ohmic contacting chain. The impedance behavior of HDPE/19 wt % CB exhibits a mixture of the two models. From the comparisons, it is concluded that the electrical conducting network in the percolation region of the CB filled HDPE composite is composed of aggregate resistance, nonohmic contact resistance, and gap capacitance, and that of the high CB loading region consists of continuously joined CB aggregate chains, which are possibly wound and assume helix‐like (not straight lines) conductive chains, acting as electrical inductions as the current passes through. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1344–1350, 2005

Influence of Divided-chamber Volume on Combustion in DME IDI Compression Ignition Engine

The DME IDI compression ignition engine was experimented for the mixture formation promotion of DME low pressure injection in a small compression ignition engine. The influence of the divided-chamber volume ratio on combustion was investigated under a connecting passage area ratio constant condition. Consequently, High thermal efficiency and low NOx emission were able to be achieved in comparatively delaying fuel injection timing, because mixture formation was promoted in the divided-chamber. And heat loss increased when the volume of the divided-chamber was large, the mixture was not promoted when it was small, and a unburnt fuel flowed out to the main chamber. Therefore, high thermal efficiency and the low emission gas were obtained by selecting suitable the divided-chamber volume in the high load region where much fuel existed. And the operating range was also expanded

20412 HCCIとATACの燃焼特性解析(OS3 エンジン燃焼と排気浄化)

Homogeneous Charge Compression Ignition (HCCI) combustion has attracted considerable interest in recent years as the new combustion concept for the internal combustion engines. HCCI has three advantages. First, low fuel consumption. Secondarily, low CO_2. Thirdly, low NOx. But, the HCCI designed in the high compression ratio has four problems. First, making to delay at the ignition timing. Secondarily, making of the burning rate dull. Thirdly, expanding the stable operation region to the high load region. Fourthly, evading of the knocking. The authors achieved the solution of these problems using internal-EGR and external-EGR.

Spatial and temporal patterns of phytoplankton composition in subtropical coastal lagoon, the Indian River Lagoon, Florida, USA

A 2 year study of the phytoplankton community was carried out in the Indian River Lagoon, USA. In terms of biovolume, the phytoplankton community was generally dominated by dinoflagellates, diatoms or cyanobacteria. Mean phytoplankton standing crops were highest in the most flow-restricted regions of the lagoon, which had the lowest mean salinity values and comparatively high total nitrogen:total phosphorus ratios. In this region, blooms of dinoflagellates were common in the first year of the study, which was characterized by an El Nino event that yielded exceptionally high rainfall levels and freshwater outflow. Picoplanktonic cyanobacteria blooms became more prominent in the second year of the study, which was characterized by below average rainfall conditions. In unrestricted flow regions of the lagoon, located near inlets to the Atlantic Ocean, diatoms were most often the dominant taxa. Regions of intermediate water turnover rates and high external loading of phosphorus had a prevalence of diatom blooms. However, the average phytoplankton standing crops in the latter regions did not reach the levels experienced in the flow-restricted parts of the lagoon. In terms of individual phytoplankton taxa, the most common bloom-forming diatoms in the Indian River Lagoon system included: Skeletonema costatum, Dactyliosolen fragilissimus, Skeletonema menzelii, Cerataulina pelagica, Odontella regia, Chaetoceros lorenzianus, Rhizosolenia setigera and Thalassionema nitzschioides. The major bloom-forming dinoflagellate species included: Pheopolykrikos hartmannii, Akashiwo sanguinea, Prorocentrum micans, the potentially toxic species Pyrodinium bahamense var. bahamense and Prorocentrum minimum. Several picoplanktonic cyanobacteria were also prominent members of the phytoplankton community, including Synechococcus elongates. The spatial and temporal patterns observed in some of these dominant species were attributable to patterns in key environmental variables, including salinity, temperature and nutrient concentrations.

Removal of Nickel from Electroless Nickel Plating Rinse Water with Di(2‐Ethylhexyl)phosphoric Acid‐Impregnated Supports

Electroless nickel plating technology is playing an increasingly important and indispensable role in many fields such as the electronic and automobile industries. As a result, the treatment of the rinse water containing about 50 mg/dm3 of nickel is becoming a serious environmental problem. Although this water is currently treated by the conventional precipitation method, a method without sludge generation is highly desired. This study explores the possibility of removing and recovering nickel from the rinse water with di(2‐ethylhexyl)phosphoric acid‐impregnated supports (D2EHPA‐IS). Macroporous polymer and oil adsorbents made of synthetic and natural fibers as the supporting materials were tested for the nickel removal abilities from simulated rinse water. In the batch experiments, more than 90% of the nickel can be adsorbed by these D2EHPA‐IS without pH adjustment. The adsorption of nickel reaches the equilibrium within 1.2 ks at 298K at a shaking rate of 140 rpm. The pH‐dependency of the nickel adsorption by the D2EHPA‐IS shows that the nickel is adsorbed by a cation exchange reaction. The adsorbed nickel can then be readily eluted with mineral acids. Most of the IS can be used many times without losing their adsorption abilities. In the column experiments, the breakthrough curves of nickel for these supports indicate that the nickel–D2EHPA complex formed at the high nickel loading region tends to dissolve into the aqueous phase. These findings lead to the conclusion that most of the studied D2EHPA‐IS are effective for the removal and recovery of nickel from an electroless nickel plating rinse water in batch mode.

Retention of Cs on zeolite, bentonite and their mixtures

The sorption behavior of cesium on zeolite and bentonite minerals and their mixtures was studied by means of a batch method and a tracer technique. All experiments were carried out in the presence of CsCl spiked with 137Cs and NaCl as a supporting electrolyte in varying concentrations. The distribution coefficients (K D) did not show significant differences at low Cs+ loadings while they decreased in the high loading region. Freundlich and D-R isotherms were applied to the adsorption data of zeolite and bentonite. Adsorption capacities and mean energies calculated from D-R isotherm parameters decreased by increasing ionic strength on both minerals. The identification of the specific uptake sites was attempted on the basis of the Freundlich isotherm. Experimentally observed distribution coefficients of Cs on two mineral mixtures were smaller than theoretically calculated values, except at the highest NaCl concentration.

電子ガバナによる新主機制御システムの開発

Diesel engines are becoming higher supercharging and higherpower than former ones in recent years. Therefore, the engines are required to install large-capacity turbochargers and a performance of engines in high-load region is given priority. As a result, some problems are caused by above the mentioned situation on the response of the engines in low-load region.Especially, when a clutch of reduction gears is on or an engine is given acceleration rapidly, a smoke of the exhaust gas and a problem of the ship's maneuver will be occurred by delay of the response of the turbocharger.As a solution of the matters, we have tried to apply electrical control by digital governor to diesel engines and the clutches, and furthermore, we have developed an all electrical control system which has included effective functions of the control based on our past experiences.We report the process that the problems have been solved by the new system with the best control on the whole propulsion system of the ships.

Proposal and evaluation of communication schemes for mobile systems employing stratospheric aircraft

AbstractIn this paper, we employed a stratospheric aircraft system in mobile communications and conducted field tests on the visibility and shadowing states based on measurements to construct a simulation of a varying communications environment. Based on these measurement data, we present the basic transmission characteristics in a mobile communication environment using stratospheric aircraft, and propose and evaluate the performances of the Time Division data transmission Among Aircraft (TDAA) scheme, which has the objective of lessening data losses due to shadowing as a specific communication scheme, and the Directional Access using Shadowing (DAS) scheme that is used in a shadowing environment in the uplink line. We also evaluate the performances of the Aircraft Position Control (APC) scheme and the Pilot Signal Control (PSC) scheme, which are flow control schemes having the objective of load distribution in high‐load regions. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 85(1): 22–34, 2002

K-2028 減圧沸騰燃料噴射による希薄予混合自己着火メタノールエンジンの燃焼改善(S26-5 DME・メタノール・燃料性状・燃料設計)(S26 新燃料,新燃焼,新原動機)

The problems of the premixed charge compression ignition methanol combustion system are that the brake thermal efficiency decreases, and CO and THC emissions increase due to a deterioration of high load combustion. The purpose of this study is to improve the high load combustion of a premixed charge compression ignition methanol engine using a flash boiling fuel injection technique. The results of this study have shown that the premixed charge compression ignition methanol combustion system using a flash boiling fuel injection technique increases the brake thermal efficiency, decreases CO and THC emissions, while maintaining low NOx emissions in the high load region. Particularly, when the brake specific energy consumption was 10 MJ/kWh at high load operation, NOx emissions decreased to as low as 3 g/kWh.

Adaptation of density distributions for optimising aluminium foam structures

Metallic foams show some potential for being produced with controlled spatial variations in their density. This suggests employing them as graded materials in space filling lightweight structures designed in analogy to cortical bone, a natural cellular material, that displays increased density in regions of high loading. In the present study the influence of the mechanical properties of aluminium foams on the results of an optimisation of the foam density distribution with regard to structural strength and stiffness was examined. Regression formulae for the relationships between stiffness and strength of metallic foams on one hand and effective density on the other hand can be fitted to the results of uniaxial compression tests of a certain brand of metallic foam. These results and additional assumptions such as overall isotropy and a yield surface suitable for cellular materials can be implemented into a finite element program adapted for performing stiffness or strength optimisation on the basis of a density adaptation similar to the remodelling of bone. Some applications are presented that show how foams with gradients in the apparent density may be employed to obtain optimal structural behaviour for classical design problems.

Toward the elimination of bias in satellite retrievals of sea surface temperature: 1. Theory, modeling and interalgorithm comparison

The along‐track scanning radiometer (ATSR), launched in July 1991 on ERS‐1, is an infrared radiometer designed to permit retrieval of skin sea surface temperature (SST) to the accuracy required for many climate research purposes. Using the prelaunch retrieval scheme, this accuracy (0.3 K) was achieved only when observations at 3.7 μm were available, i.e., SSTs derived from nighttime scenes before the failure of this channel in May 1992. Retrievals using only channels at 11 and 12 μm suffered significant biases. First, cold biases of up to 1.5 K arose from the radiative effects of the unanticipated presence of a significant loading of stratospheric aerosol following the eruption of Mount Pinatubo in June 1991. Second, cold biases of up to 0.4 K were associated with regions of high water vapor loading. We solve the first problem by choosing retrieval coefficients to be orthogonal to the modeled changes in brightness temperatures caused by variations in stratospheric aerosol optical depth. We attribute the second problem to deficiencies in radiative transfer modeling of water vapor continuum absorption and show that use of an updated parameterization reduces bias from wet atmospheres. Applying the new retrieval coefficients to ATSR data, we find good consistency between SSTs retrieved with and without the 3.7 μm channels, the global mean and standard deviation of differences between retrievals being of the order of 0.05 K and 0.25 K, respectively. We therefore anticipate that reprocessing ATSR data using our new retrieval scheme will result in a substantially improved record of ATSR SST, in that the following should be reduced to insignificant levels: (1) the artefactual trend (previously ∼0.25 K yr−1 in tropical regions) corresponding to the decaying load of post‐Pinatubo aerosol, (2) the discontinuity in SST retrievals (previously up to 0.7 K) associated with the failure of the 3.7 μm channel, and (3) cold biases (previously ∼0.4 K) in wet tropical regions. Thus this work represents a significant advance in terms of the quality of ATSR SSTs for climate research. The techniques are also applicable to both the ATSR‐2, flying on ERS‐2, and the advanced ATSR (planned for launch on the Envisat platform in 2000). However, we note that even with the improved physical modeling on which the new retrieval coefficients are based, we do not yet meet the stringent requirement of 0.1 K decade−1 stability in retrievals for climate change detection purposes.

Structural Characteristics of Tightening Point for Interior Equipments on Railway Car Body Made of Aluminium Hollow Extrusions.

Structural characteristics of the tightening point between railway car body and interior equipments conposed of a tightening bolt and an attachment rail made with aluminium hollow extrusion is studied. To investigate the structural characteristics of the attachment rail and dispersion of axial force on the tightening bolt must be separately considered. Scatter of the structural characteristics of the attachment rall accompanied with load relies on constrained force of the tightening bolt is carried out. Dispersion of residual stress of the attachment rail which is caused by bolt tightening shows the same load-stress relationship in high load region an no-fixed model. The FEM calculation with fixed and free model of the tightening bolt is in good agreement with the load test result.

Structure-related paraffin sorption in ZSM-5

Normal hexane sorption isobars for high silica ZSM-5 display an inflection; the derivative curve clearly reveals two, equal area, distinct peaks, indicating two adsorption regimes for hexane in ZSM-5. The break between the two peaks occurs at 3.7 hexane molecules/unit cell, close to 4, the number of intersections (I), the number of straight channel double ten rings (S), and the number of zig-zag channel double ten rings (Z)/unit cell. The high loading region (5–8 molecules of n-hexane/unit cell) hexane desorbs rapidly relative to desorption in the low loading region (0–4/unit cell). n-Decane does not show this effect; a single peak is observed in its derivative desorption curve. The length of the n-hexane molecule is equal to the length of potential channel adsorption segments, indicating that molecular length is the critical factor. Entropic factors are likely responsible for the weaker adsorption at higher loadings.

Effect of normal load on microscale friction measurements

Friction force microscopy (FFM) was used to study microscale friction between a sharp tip and various samples. Effect of normal load and tip material on the coefficient of friction has been studied. Friction force as a function of normal load of virgin silicon with a thin film of native oxide and dry-oxidized SiO2 coating showed two distinct slopes. The coefficient of friction in the low load region of less than about 15 mN is lower than that in the high load region. The critical load at which the coefficient of friction starts to increase corresponds to the specimen hardness. Ploughing at high loads is believed to be responsible for high values of the coefficient of friction. The coefficient of friction of polished natural diamond remains virtually independent of normal load because no ploughing occurs. The coefficient of friction on a macroscale is higher than that on a microscale for comparable contact stresses. When measured for the small apparent area of contact and very small loads used in microscale measurements, the indentation hardness and modulus of elasticity on a microscale are higher than that at the macroscale. This reduces the degree of wear at the microscale. In addition, small apparent areas of contact in microscale measurements reduces the number of particles trapped at the interface and thus minimizes the ploughing contribution to the friction force. Based on this study, it is concluded that measured values of the coefficient of friction on a microscale are a strong function of normal load and the apparent area of contact. Ultralow values of the coefficient of friction and near-zero wear can be achieved with microscale components at very light loads in the absence of significant ploughing.

Selective cracking and etherification of olefins

Normal hexane sorption isobars for high silica ZSM-5 display an inflection; the derivative curve clearly reveals two, equal area, distinct peaks, indicating two adsorption regimes for hexane in ZSM-5. The break between the two peaks occurs at 3.7 hexane molecules/unit cell, close to 4, the number of intersections (I), the number of straight channel double ten rings (S), and the number of zig-zag channel double ten rings (Z)/unit cell. The high loading region (5–8 molecules of n-hexane/unit cell) hexane desorbs rapidly relative to desorption in the low loading region (0–4/unit cell). n-Decane does not show this effect; a single peak is observed in its derivative desorption curve. The length of the n-hexane molecule is equal to the length of potential channel adsorption segments, indicating that molecular length is the critical factor. Entropic factors are likely responsible for the weaker adsorption at higher loadings.