An electric motor propels the bus, but its regenerative braking system also pressurizes hydraulicfluid.
一个电动发动机推动这辆公交车，但其再生制动系统也对液压流体加压。
2
One company has presented an idea in which metal strips inserted in pavements and roads operate fly wheels by means of a piston action using hydraulicfluid.
一个公司提出这样想法：嵌在人行道和路面上的金属条用液压活塞的作用使飞轮转动。
3
The hydraulicfluid used is similar to automatic transmission fluid found in most vehicles.