Narrow Results

The method of quantitative analysis of oil samples in in-air PIXE has been developed on the basis of a standard-free method. The components of the continuous X-rays originated from air and backing film can be exactly subtracted using a blank spectrum after normalization by the yields of Ar K-α X-rays. The method was developed using nine oil samples including standard oils and its accuracy was confirmed by comparing the results with those obtained by the internal-standard method. Validity of the method for practical oil samples was confirmed for various kinds of oils such as engine, machine and cooking oils. It was found that the method is effective for various kinds of oils whatever elements we designate as an index element.

The smoke emission of diesel engine is being recognized as the main cause for the serious air pollution related problem affecting our environment. In this study, we investigated the possibility of biodiesel fuel to reduce smoke emission as an alternative fuel for diesel engine. Additionally, gas chromatography was used to analyze not only total amount of HC(hydrocarbon) but also the amount of HC components from C₁ to C₆ in the exhaust gas to determine the exact source responsible for the remarkable reduction in the amount of smoke emission. Because biodiesel fuel has about 10 vol-% oxygen content, the combustion process of the diesel engine is improved and exhausted smoke emission density especially decreased.

In this study, the possibility of biodiesel fuel and oxygenated fuel (dimethoxy methane ; DMM) was investigated as an alternative fuel for a naturally aspirated direct injection diesel engine. The smoke emission of blending fuel (biodiesel fuel 90vol-% + DMM 10vol-%) was reduced approximately 70% at 2500rpm, full load in comparison with the diesel fuel. But, engine power and brake specific energy consumption showed no significant differences. But, NOx emission of biodiesel fuel and DMM blended fuel increased compared with commercial diesel fuel due to the oxygen component in the fuel. It was needed a NOx reduction counter plan that EGR method was used as a countermeasure for NOx reduction. It was found that simultaneous reduction of smoke and NOx emission was achieved with BDF (95 vol-%) and DMM (5 vol-%) blended fuel and cooled EGR method (15%).

In order to improve the fault diagnosis rate and efficiency of diesel engine, the PCA-RBF neural network as a new algorithm was constructed by combing the character extraction ability of PCA with the nonlinear approximation ability of RBF neural network. Firstly, eight factors which affected the fault types of diesel engine were analyzed and three principal components were extracted by PCA. Secondly, the data obtained from the three principal components were taken as the input of RBF neural network which was trained and tested. Finally, the PCA-RBF neural network was verified through simulation. The simulation results show that the network has fewer training steps, less training and higher training accuracy.

Effect of oxygen components of fuels on exhaust emissions has been investigated by applying an indirect injection (IDI) diesel engine. This research analyzed variation and/or difference of the engine performance and exhaust emission characteristics of the IDI diesel engine by fueling the commercial diesel fuel and four different mixed ratios of oxygenated blended fuels. Effect of the exhaust gas recirculation (EGR) method was analyzed on the NOx emission characteristics. Ethylene glycol mono-n-butyl ether (EGBE) contains 27% of oxygen components in itself, and it is a kind of effective oxygenated fuel of mono-ether group. Smoke emission from the EGBE was reduced remarkably relative to the commercial diesel fuel. The EGBE can supply oxygen components sufficiently at higher diesel engine loads and speeds. It was found that a simultaneous reduction of the smoke and the NOx was achieved with the oxygenated fuel (10 vol-%) and the cooled EGR method (10%).

This study aims to master the changing of vehicles' diesel engine and supercharger work load, and to find the regularities within. Besides forming the basis of new-type diesel engines and supercharger's endurance and reliability design, it can also provide an important basis for the diesel engine which is on active duty as well as supercharger's life prediction, extension and reliability test. This article focuses on specific types of armored vehicles and developed the power union load testing system. It can provide technical support for further accumulating and formulating the load spectrum of vehicle and supercharger.

This paper investigates the feasibility of recycling waste heat from a diesel engine, and also the effects of using ethanol-diesel oil as an alternative fuel. Through thermodynamic analyses, the study reveals that a significant amount of energy is contained in both the exhaust gas and cooling water, and that recycling this energy will reduce emissions, conserve energy, and improve the thermal and exergy efficiency of the diesel engine. The use of ethanol-diesel oil will lead to significantly reduced exhaust emissions without significant impact on the engine's performance parameters.

This paper mainly focuses on designing the intelligent system that includes test project, test resource, test data and test document management; building the relationship among test management system, test execution system, central data system, customer client and design platform; and introducing the flow direction of data and task. The paper also proposes a scheme of multi-task management, data management and document management. Based on the mainline of test task, the digital technical preparation is conducted, the process of bench preparation is controlled. The test program is almost automatically run, the collected data transfers between different systems and finally the intelligent system is realized. For an engine, the process of test operation is further introduced. The results show that the system is feasible.

The combustion and NOx (Nitrogen Oxide) emission characteristics experiment fueled with conventional diesel fuel and four different fuel blends of acidic oil biodiesel (B5, B10, B15 and B20) were conducted in a four-cylinder, electronic controlled high-pressure common-rail, turbocharged diesel engine without any structure modifications. The results showed that operations with acidic oil biodiesel blends had increase in ignition delay, maximum in-cylinder pressure, heat release rate peak in diffusion combustion duration, cumulative heat release and maximum in-cylinder temperature compared with baseline diesel. In addition, the heat release rate peak and in-cylinder pressure rise rate peak in premixed combustion duration of biodiesel blends were decreased and their crank angular positions were lagged obviously. The NOx emission of biodiesel blends increased, especially at high loads.

For a four-cylinder diesel engine with a conventional turbocharger, it was matched by a variable nozzle turbocharger (VNT), and the response of VNT turbine was investigated at the given 1000 rpm engine speeds. To verify the better response of the matched VNT turbine at 1000 rpm engine speed, the engine software AVL-BOOST, in present paper, was used to model the working process of engine, the relevant stable parameters such as the velocity, pressure, temperature and flux of VNT turbine before and after its operation were obtained. The 3-Dimensional solid modeling software was used to model the internal flow field of VNT turbine, which was also numerically simulated by CFD software Fluent. As thus, the 3-Dimensional viscous flow characteristics of the internal flow field were obtained. The pressure, temperature, velocity distribution of entire internal fluid and the nozzle ring field were summarized according to the numerical simulation, implying the response of VNT turbine can be increased at low engine speeds. The full research results can provide the fundaments for optimizing the best matching of the VNT and the engine.