Material Composition and Engineering Characteristics of Red Clay in Guigang, Guangxi

There is fine and uniform clay with aluminous and ferrous cementation in the red clay found in Guigang, Guangxi. It has the characteristics of shrinkage outwardly, rigid upper but soft lower and well grown fissure. In addition there are engineering characteristics such as high water content, low compactness and low compressibility, high strength and high contractility but slight expansibility. This paper discusses the red clay's engineering characteristics and its change regulation with depth by analyzing changes in the red clay's grain size composition, mineralogical constitution, and chemical composition.

Compacting Deformation Engineering Characteristics of Weathered Soft Rock Mixture in Subgrade

The engineering characteristics of weathered soft rock are important contents of soft rock mechanics. They also play a significant role in compacting deformation, which has been known to exert a significant amount of influence on the stability of highway filling subgrade engineering. In an effort to investigate this aspect of the problem, compacting tests and unconfined compressive strength tests have been carried out on weathered argillaceous slate and pelitic siltstone rocks, which are broken and graded before the test. The testing results indicate that the relationships of both between stress and strain and between axial strain and tangent modulus are exponential relationships; the size of the grain plays some influence on the deformation modulus, whereas the water content impacts the compressive strength greatly, which shows quadratic function; the unconfined compressive strength is linear with the dry density of loose soft rock mixtures. Therefore, the water content must be controlled in both the design and the construction of subgrade engineering of soft rock filling, and at the same time some effective measures should be taken to reach the requirement of compaction.

New Leiderman–Khlystov Coefficients for Estimating Engine Full Load Characteristics and Performance

The paper presents a method of calculating the full load engine characteristics based on the Leiderman–Khlystov relation. Because the values of the coefficients of the discussed function available in literature were determined for obsolete engine designs, an attempt was made to update them. To this end, a chassis dynamometer was used where a database of results had been built for a variety of vehicles. Following the data collection, the coefficients for variety of fueling system(six groups: fuel injected gasoline and turbocharged gasoline, spark ignition LPG Ⅰ–Ⅱ and Ⅳ generation, naturally aspirated diesel and turbocharged diesel) were determined. The identification of the coefficients was carried out in Matlab-Simulink indicating the applicability of the said function for most of the engines, yet the recent popularity of turbocharged gasoline engines requires an additional analysis of the possibility of use of a different functional description. The full load engine characteristics is a basis for the vehicle performance characteristics and, further, for modeling of traffic in a variety of aspects of the vehicle operation.

Engine performance and combustion characteristics of a direct injection compression ignition engine fueled waste cooking oil synthetic diesel

Biodiesels produced from various feedstocks have been considered as alternative fuels used in internal combustion engines without major modifications.This research focuses on producing biodiesel from waste cooking oil(WCOSD)by the catalytic cracking method using MgO as the catalyst and comparing the engine operating characteristics of the test engine when using WCOSD and traditional diesel(CD)as test fuels.As a result,the brake power of the test engine fueled WCOSD,and traditional diesel is similar.However,the engine fuel consumption in the case of using WCOSD is slight increases in some operating conditions.Also,the nitrogen oxides emissions of the test engine fueled WCOSD are higher than those of CD at all tested conditions.The trend is opposite for hydrocarbon emission as the HC emission of the engine fueled by WCOSD reduces 26.3%on average.The smoke emission of the test engine in case of using WCOSD is lower 17%on average than that of CD.However,the carbon monoxide emissions are lower at the low and medium loads and higher at the full loads.These results show that the new biodiesel has the same characteristics as those of commercial biodiesel and can be used as fuel for diesel engines.

Design of Synchronous Drive Mechanism of Opposed-Piston Hydraulic-Output Engine

In order to improve the thermal power conversion capacity of the internal combustion engine,combined with existing opposed-piston two-stroke engine（ OP2S） and hydraulic free piston engine（HFPE）,the integral structure for a newtype of opposed-piston hydraulic-output（ OPHO） engine has been designed,an operating principle has been introduced,the composition of its synchronous drive mechanism has been carefully analyzed,and a mathematical model has been built. In addition,the kinematics models of both the mechanism and the conventional crank-link mechanism have been established by utilizing MATLAB,and the movement rules of the pivotal moving components have been obtained. According to the simulation results,the piston movement of this newtype of opposed-piston hydraulic-output engine reveals a prominent asymmetry compared to the conventional crank-link engine. Under a fixed engine revolving speed,the compression time of the opposedpiston hydraulic-output engine is shortened while the expanding time is lengthened,thus the gas turbulence intensity is strengthened around the top dead center（ TDC） position. Meanwhile,the piston obtains a longer isometric process compared to conventional engines,which could be benefitial to enhance the combustion efficiency.

Structural Analysis and Improved Design of the Gearbox Casing of a Certain Type of Tracked Vehicle

Loads on a gearbox casing of a certain type of tracked vehicle were calculated according to the engine＇s full load characteristic curve and the worst load condition where the gearbox operated while the tracked vehicle was running, and then stiffness and strength of the casing were analyzed by means of Patran/Nastran software. After a- nalysis, it was found that the casing satisfied the Mises ＇ yield condition; however, the stress distribution was hetero- geneous, and stresses near the bearing saddle bores of the casing were higher while those in other regions were much less than the allowable stress. For this reason, thicknesses of the casing wall on bearing assembling holes needed in- creasing, while those in other places can decrease. After much structural improving and re-analysis, the optimal casing design was found, and its weight decreased by 5% ; the casing still satisfied the Mises yield criterion and the stress distribution was more homogeneous.

Research on windmill starting characteristics of MTE-D micro turbine engine

Micro turbine engine （MTE） is an important kind of propulsion system for miniature unmanned aircraft or missiles, because of its better high-speed performance （than propeller propulsion） and higher propulsion efficiency （obviously than rockets）. Windmill start is a common air-starting mode used in micro turbine engine. The windmill starting characteristics are important to the practical use of micro turbine engine. In this paper, the windmill starting characteristics research for a 12 cm diameter （MTE-D） micro turbine engine is carried out by experiment and numerical simulation. The characteristic of rotor mechanical losses at low-speed condition is stud- ied, and the engine common working line of windmill starting process is obtained. Based on the engine windmill characteristics, the propane ignition characteristics under different inflow conditions are researched, and the envelope of propane ignition and propane flameout is determined. The experimental research of fuel supply and ignition characteristics is completed, and the envelope of fuel supply and ignition is obtained. The windmill stage, propane ignition stage, fuel ignition stage and acceleration process from idling-speed to 80% full speed of MTE-D micro turbine engine is optimized, and the optimization windmill starting parameters are collected. The successful wind-mill starting experiment under this condition with engine speed up to 80% full speed indicates that these starting parameters are reasonable. All the starting parameters of MTE-D micro turbine engine obtained in this work are dimensionless parameters, and the conclusions obtained in this study have some reference to other micro turbine engines with the similar structural form and starting process.