Patent ID: 8646422

Claim:
An electro-hydraulic variable valve lift apparatus comprising: a housing; a driving cam; a pump piston which forms a main chamber with the housing, reciprocates within the housing according to rotation of the driving cam, and forms hydraulic pressure within the main chamber; a pump piston elastic portion disposed for elastically supporting the pump piston; an oil pressure controller communicating with the main chamber in order to control hydraulic pressure within the main chamber; a hydraulic piston slidably disposed within the housing, includes a first body having a first diameter and a second body having a second diameter larger than the first diameter, and is operably connected with a valve; and a piston guide disposed between the housing and the hydraulic piston for guiding the hydraulic piston; wherein: the piston guide is disposed between the first body and the housing; the first body and the housing form a first auxiliary chamber; and the second body, the housing and the piston guide form a second auxiliary chamber; wherein the first body comprises: a first hydraulic line selectively connecting the first auxiliary chamber and the second auxiliary chamber; and a second hydraulic line continuously connecting the first auxiliary chamber and the second auxiliary chamber; and wherein the first hydraulic line is closed by the piston guide when the valve is closed.