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The model of bio-diesel fuel's free spray was founded by using three-dimensional Computational Fluid Dynamics (CFD) software. The distance of fuel jet penetration and sauter mean diameter (SMD) of bio-diesel fuel spray were computed and discussed. The atomization progress of fuel jet was simulated and the pictures of high speed photography were analyzed and compared in detail. The results showed that the cone angle of bio-diesel fuel was smaller than that of diesel fuel nearly 3 degrees. The high speed photograph of fuel jet along with time was similar to the simulated results. The distance of fuel jet penetration and SMD of bio-diesel fuel was different from that of diesel fuel, and the differences changed along with the time. We found that the main reasons were that the density and viscosity of bio-diesel fuel were greater than that of diesel fuel. The fact will have great effect on the combustion and performance of the engine.

The physical and chemical characteristics of a new composite oxygenated fuel, whose code name was FHYJ, and F10 (conventional diesel blended with 10% FHYJ by volume and no additives) have been analyzed, the power, economy, combustion performances and emission have been discussed and compared when burning F10 and diesel fuel in a four-stroke, direct injection and naturally aspirated four cylinders automotive diesel engine. The results indicate that FHYJ can be used blended with conventional diesel in automotive engines without any modifications to the engine. FHYJ is more suitable to diesel engine for its better performances. The combustion velocity can be increased, while the knocking tendency can be decreased. FHYJ/diesel blend fuel is much friendlier to the environment than fossil fuel, especially with regard to reducing smoke emission.

Theoretical analysis on the linearity of electronic throttle sensor of diesel engine. The magnetic induction density of radial magnetic field is the key factor that affects the linearity of electronic throttle sensor of diesel engine, while the magnetic induction density is affected by such factors as the length and radius of the primary coil and prejudicial distance and radius of prejudicial disc and primary exciting current. After optimizing calculation of the linearity of electronic throttle sensor, the parameters has been optimally determined. To deal circuit matching with electronic throttle sensor. It was constantly adjusted for control parameters of several parts of apparatus of electronic throttle sensor so that its linearity can be optimal. Several analogue test of diesel engine are made on the basis of electronic throttle sensor control system of adding loads and decreasing loads.

Using methanol to replace the diesel fuel in diesel engine is a simple way in using of alternative fuel. But the main problems are that the max. cylinder pressure and the cylinder pressure rising will be increased. This increases the mechanical load engine noise and affects the engine reliability. Also limits increasing the ratio of methanol to diesel fuel. This paper presents an new way of using EGR to control the cylinder pressure and to raise the ratio of methanol to diesel fuel. There are many ways to burn methanol in diesel engines. Generally, the liquid methanol is vaporized by heating of exhaust pipe or and cooling water, then it mixes with air through intake pipe, finally, burns in the cylinder. The advantages of this method are that the structure of diesel engine needs no change. By using the exhaust heat to vaporize the liquid methanol, the wasted heat can be utilized again. So it is helpful to improve the thermal efficiency. However, there are some shortages.

An expert system for analysing the performance and diagnosing faults of d.I. diesel engine is presented in this paper. This system consists of three parts. First is the transient data acquiring part by which the incylinder pressure, fuel pipe pressure and other parameters can be acquired through the A / D transforming circuits. Second is the simulative calculation and analysis part by which most of the parameters, such as the fuel injection rate, fuel heat release rate etc. can be calculated. Third is the expert diagnostic part established on the fuzzy theory, which is applied to evaluate the matching relations among various transient parameters. Some faults of engine can be detected by this part. Furthermore, the proposals to improve the performance of engine can be put forward by this system.