就是在引擎后面,空气经过空气过滤器后进入的那个东西。右端出来的一个很短的胶皮软管接到引擎右上端,连接引擎的地方(在引擎上)有非常薄的油膜
Exhaust Gas Recirculation (EGR) valve, which is one-way thriough vavle (or sensor if it is electrical control). If it leak, you lose a little bit energy. But it is mainly for pollution control.