Volvo Truck Corporation

Volvo Trucks Ab

Volvo Lastvagnar Ab

Romain Riviere

Romain Le Forestier

Damien Didiot

Foudil Abderrahim

Philippe Grynberg

Arnaud Roque

A valve actuation system for an internal combustion engine The valve actuation system (S) for an internal combustion engine comprises: &#x22c5;a rocker () pivotably mounted around a pivot axis (A), comprising: &#x22c5;a driven end portion () for cooperating with a rotating cam including a main bump and at least one smaller auxiliary bump; &#x22c5;an actuating end portion () including a piston () for opening at least one valve of the engine following the cooperation of the driven end portion () with a bump of the cam, the piston () being slidably mounted relative to the rocker () between a extended position allowing said piston () to open said valve when the driven end portion () contacts the auxiliary bump, and a retracted position preventing said piston () to open said valve when the driven end portion () contacts the auxiliary bump; &#x22c5;a fluid circuit for causing the piston () to move from its retracted position to its extended position; &#x22c5;a reset circuit comprising a reset valve () rotatably mounted relative to the rocker (), between an inactive position, and an active position in which the reset valve () causes the fluid to be drained out of the fluid circuit to allow the piston () to move towards its retracted position; &#x22c5;a lever () pivotably mounted around a pivot axis (A), the lever () having a driven end portion () adapted to cooperate with a rotating reset cam including a bump, and an actuating end portion () for rotating the reset valve () from its inactive position towards its active position following the cooperation of the lever driven end portion () with the bump of the reset cam; &#x22c5;rotational coupling means () between the lever () and the reset valve (), said rotational coupling means having a transmission ratio greater than 1.

Valve actuation system for an internal combustion engine

A valve actuation mechanism includes rockers moved by a camshaft, each rocker being adapted to exert a valve opening force on at least a portion of a valve opening actuator of each cylinder, via an activation piston, housed in a bore of the rocker and movable with respect to the rocker under action of a fluid pressure raise in a chamber fluidly linked to the bore, from a first position to a second position, in which a cam follower of the rocker reads at least one auxiliary cam sector of a cam of the camshaft so as to perform an engine operating function. Each rocker includes a reset valve adapted to reduce fluid pressure in the chamber. The valve actuation mechanism includes, for each rocker, a reset cam profile adapted to open the reset valve when the activation piston has to be moved from its second position to its first position, and each reset valve includes a cam follower adapted to drive the reset valve as a function of the movement of the reset profile.

Valve actuation mechanism and automotive vehicle comprising such a valve actuation mechanism

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Pollionnay, France

Romain Riviere