スワール噴射弁による間欠燃料噴霧の高温高圧場特性

摘要

燃料直接噴射火花点火（DISI：Direct Irjection SparkrnIgnition）機関の改善のため，直接噴射ガソリン噴霧の構rn造の理解が必要となる．そのような燃料噴霧に関してrnは，加圧雰囲気下での噴霧形状に関する研究，噴射rn率と噴霧特性の相互評価，時間分割法を用いた評rn価，多段噴射スワール噴射弁の噴霧特性評価，噴rn霧とその周囲流の同時計測，ノズル近傍の噴霧速度rnおよび液滴径計測など多くの研究が行われている．%An experimental study on an intermittent fuel spray initiated from a swirl injector proposed for direct injection spark rnignition (DISI) engines has been carried out in order to clarify the effects of back pressure and ambient temperature. The rnmeasurements have been made in a constant volume chamber in which maximum pressure and temperature reach 1.1 MPa and 423 K, rnrespectively. Visualization of the spray is performed by a high speed CCD video camera with laser sheet technique. Droplet rnvelocity and diameter are acquired by phase Doppler anemometry (PDA), and processed by a time-dividing method which divides rnthe phase matched spray information into five distinct periods. The effects of ambient temperature on the droplet velocity rnappear at the tip of the spray. The decrease in Sauter mean diameter D_(32) is observed at core region of the sprays when rnthe ambient temperature is high conditions under both back pressures.