Study of the Effect of Mixture Preparation on the Combustion of Gasoline HCCI Engine
| Autor: | Vo Cong Anh, 武功英 |
|---|---|
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 99 Homogenous Charge Compression Ignition (HCCI) combustion has been regarded as a promising technology to realize a reciprocating engine with high thermal efficiency and low environmental impact. HCCI combustion engines are characterized by use of a premixed gas phase charge, unthrottled operation, high compression ratio, and mixture auto-ignition. In this thesis, a practical experiment is used to study the effect of mixture preparation on gasoline HCCI combustion under more controlled parameters. To carry out the experiment, a specific intake system has been designed and installed in a small single cylinder engine to analyze the effects of intake air temperature, air fuel ratio and EGR composition on characteristic combustion and emission. The engine used to carry out this experiment is modified from a Yamaha XC-125M engine. The cylinder head is originally designed for a spark ignited, port fuel injected engine. The compression ratio is increased from 10.3 to 14.3 by using a larger piston and a cylinder liner adaptor bolted onto the block. With the intake system setup, different compositions of mixture preparation are allowed to be established. The experimental results indicate that, the most effective factors to HCCI combustion characteristics are the intake air temperature, air fuel ratio and EGR ratio. When EGR ratio and air fuel ratio increase, the burn duration decreases due to the lower peak pressure. The value of IMEP reduces slightly along with the increase of air fuel and EGR ratios. In addition, the increases of air fuel and EGR ratios also increase the HC and CO emissions while NOx emission is reduced. As intake air temperature increases, the engine has a lower IMEP value although the cylinder pressure is increased. Besides, the increase of intake air temperature makes the NOx emission increases significantly, especially at high temperature. The effects of intake air temperature, air fuel ratio and EGR ratio on HCCI combustion are all interconnected. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|