【摘要】 基于所研制的单活塞式液压自由活塞柴油机原理样机,对缸内气体流动规律进行了数值仿真。研究结果表明,缸内气流运动规律受活塞运动规律的影响,与传统内燃机相比,HFPDE缸内气流运动规律如下:压缩冲程初始阶段,由于活塞运动速度较小,缸内平均气体速度较小;压缩冲程后期,活塞在上止点附近运动速度增大,缸内气体加速径向流出燃烧室,平均径向速度增大,挤流效果增强;膨胀冲程早期,活塞较大的运动速度使得平均径向速度大幅增大,逆挤流效果也明显增强;上止点附近挤流和逆挤流受活塞瞬时速度影响,随着相同活塞位置所对应的活塞运动速度的增大,平均径向速度增大,挤流和逆挤流效果增强。更多还原

【Abstract】 Based on the development of the single-piston hydraulic free piston diesel engine prototype, numerical simulation on in-cylinder gas motion was studied. The study results showed that the in-cylinder gas motion was influenced by the piston motion. Compared with the traditional internal combustion engine,the in-cylinder gas motion characteristics of hydraulic free piston engine are as follows: in early compression stroke,the average velocity of in-cylinder gas is smaller due to the smaller piston velocity; in late compression stroke, the piston movement velocity increases near the TDC, in-cylinder gas accelerated radial flow out from the combustion chamber,the average radial velocity increases,the squish enhancement; in early expansion stroke,the higher piston movement velocity lead to the average radial velocity substantial increases and the inverse squish significantly enhanced in this period. The piston instantaneous velocity influenced the squish and inverse squeeze nearby TDC,with the piston velocity increasing at the same piston position,the average radial velocity increasing,squish and reverse squish enhancement.更多还原