The Study of Gasoline Engine''s Performance and Emissions Under the Implementation of Gasoline Direct Injection System on the Large Size Single Cylinder Engine

• Main Authors: Ta-Wei Tang, 唐大為
• Other Authors: Kuo-Liang Shih
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/00691414009824417125

碩士 === 國立雲林科技大學 === 機械工程系碩士班 === 99 === This study modified the GDI gasoline engine to study the engine performance, combustion, and the exhaust emissions. A 500c.c. single cylinder engine is equipped with the common rail 100 bar high pressure injection system to replace the original PFI 3.5 bar injection system. Te injector is replaced on the center of the cylinder head and its injection angle is perpendicular to the piston surface. The PC-based controlling system is used to adjust the fuel injection timing and duration. The engine speed and the throttling position are varied in this study. The fuel injection angle is chosen to be 150°CA(intake stroke) and 210°CA(compression stroke). The results show the engine volumetric efficiency is increased by 2 % due to the fuel evaporation inside the intake manifold for the PFI design. The engine torque is increased by 5~20% too. The CO and HC emissions are reduced by 40%~80% and 30%~50% if the injection timing is selected as 150°CA ATDC. Due to the lack of fuel evaporation inside the PFI intake manifold, the volumetric efficiency is increased by 2%. The increased fuel injection pressure and fuel impingement cause the better fuel evaporation and the better fuel combustion. The GDI engine has lower Co and HC emissions. However, since the spark plug is placed near the cylinder liner, the flame propagation has sluggish performance and thus the engine cylinder pressure and engine torque are reduced by 5%~35%. The NO emission is also decreased by 25%~45%. The spray droplet distribution and evaporation in the combustion chamber are very important to the fuel combustion results. The design of the GDI engine geometry and injection system must be carefully selected to achieve the best GDI performance.