The Effects of Heating Up the Intake Manifold on the Spray Impingement Behavior and the Motorcycle’s Exhaust Emissions

• Main Authors: Ching-Chun Hsu, 徐敬鈞
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/39632891267019563780

碩士 === 國立雲林科技大學 === 機械工程系碩士班 === 97 === This research applies the KYNCO 125c.c. EFI engine to study the spray impingement phenomena inside the intake manifold. The Intake manifold and the cylinder head assembly is modified for the high resolution digital camera photo taking with the help of digital timing control of the stroboscope.. The spray impingement and the consequent surface wetting phenomena inside the cold intake manifold is observed and compared to the heating up manifold results. The real engine’s intake manifold is also equipped with the heating device for the measurements of engine performance and exhaust emissions. The EFI engine has the fuel spray directly aimed on the intake value during the cyclic fuel injection period. Since the fuel is injected per cycle the concentrated fuel jet can cause the local impinged site’s surface temperature drops and has the liquid film formed on the surface. If the intake system is heated up the liquid film appear to as boiling behavior which is confirmed indirectly by measuring the engine output and exhaust emissions. The comparisons between the original and the modified intake manifold system are also included in this study. The results show the engine torque is reduced by 22 % compared to the original engine set when the intake manifold is modified. The torque is up by 4.25% if the modified manifold is heated up compared to the modify manifold without heating. The CO reduction is 12% and 35% for the two modified and the heated up cases. The HC is reduced by 18% and 10% respectively. The modification of the intake manifold cases scattered spry impingement on the intake valve and manifold assembly so that the atomization is enhanced and thus the emissions are reduced. Further heating up the intake system causes better droplets rebounding and liquid fuel evaporation so that the exhausts are further reduced. However, the heating up of the intake manifold can cause the drop of volumetric efficiency so that the engine torque is also reduced. After the study of this intake system modification and heating up effects on the engine perforce, the domestic scooter manufactory can design a better intake system to cut down the exhaust emissions.