Research And Design Of Electric Pressure Charging System To Small-Size Diesel Engine

Small-size diesel engines are widely used on agricultural vehicles and farm tractors.Small power is engine's typical feature , when agricultural vehicles and farm tractors work under overloaded conditions,the diesel engine's power will be insufficient, fuel consumption will increase, the emission performance of the diesel engine will be not so well. Designing a supercharging system for diesel engine is a very good choice to solve these problems.In the pressurized and non-supercharged case, the speed characteristics of test and load experiments of S195 diesel engine have been done. We analysed supercharge effect in increasing the power of the engine,reducing fuel consumption and improving the emission performance.Load experiments of S195 diesel engine have also been done when supercharger works at different speeds. The test results have provided the basic theories to designing a more powerful supercharging system.Engine's insufficient power supply is only an incident, an idea of increasing the air intake system's air pressure of the diesel engine temporarily is bringed up.It can improve the dynamic performance of the engine,improve the emission performance of the engine ,and reduce environmental pollution. Considering the engine's power is insufficient, in order not to consume the engine's power, an additional dc motor is used to drive supercharger.In such style,we can control pressure charging System freely.When diesel engine's power is under shortage , pressure charging system works, on the other hand, pressure charging system will not work. It can reduce the energy consumption, and diesel engine components will not wok under greater time pressure ,the engine's life will not be shorted.We analyzed a variety of types to increase air pressure, and compared the centrifugal compressor and Roots-type compressor, pointing out their advantages and disadvantages, and ultimately choose the Roots-type supercharger system as the compressor machine. A supercharging system is designed to diesel engine below 1.0L, the pressure ratio and the flow of air supercharging system are fixed. According to pressure ratio and air flow ,we design a Roots supercharger, the supercharger is driven by a motor.Using 3D design software Pro-E,we designed the model of supercharger. Using finite element software Ansys 10.0, the stress and deformation analysis of supercharger's key components have been done. We improved the supercharger on rotor's material and the structure of the supercharger's impeller. Considering the supercharger's pressure ratio is not very high, we improved the Roots supercharger's outlet flow road to increase the pressure ratio ,and fluid analysis software Fluent have been used to prove that improving supercharger's outlet flow road can increase the pressure of the air.