C.r.f. Societa Consortile Per Azioni

Luca Gentile

Francesco Vattaneo

Gianluca Canino

Claudio Lanfranco

Laura Gianolio

Davide Peci

Maria Grazia Lisbona

In an engine having an electronically controlled hydraulic system for variable actuation of intake valves, an operating step of refilling, prior to ignition of the engine, is activated to refill a pressure chamber of the system with fluid when, after prolonged engine inactivity, the chamber has been emptied. In this refilling step, fuel supply to the engine is inhibited, and a camshaft is rotationally driven following upon activation of an engine-starting electrical machine. In this way, a pumping member associated to a tappet for actuating an intake valve is used as a pump for drawing fluid into the pressure chamber from an auxiliary fluid tank. During this step, a control valve is opened and closed in synchronism with movement of the pumping member so as to be open when the pumping member advances towards the pressure chamber and closed when the pumping member moves away from the pressure chamber.

Internal-combustion engine with an electronically controlled hydraulic system for variable actuation of the intake valves, provided with a device for refilling the system with fluid

A supercharged diesel engine is equipped with an electronically controlled hydraulic system for variable actuation of the intake valves of the engine. The cam that controls each intake valve has an additional lobe for causing an additional opening of the intake valve, during the expansion and exhaust strokes, so as to provide an exhaust-gas recirculation directly inside the engine. The aforesaid additional lobe has its descending stretch radiused to the main lobe with a stretch corresponding to a non-zero lift of the valve in such a way that the profile of the lift of the valve has a portion corresponding to a substantially non-zero value of the lift that radiuses the descending stretch of the profile of the additional lift to the ascending stretch of the profile of the main lift.

Diesel engine having cams for controlling the intake valves, which have a main lobe and an additional lobe radiused to each other

A supercharged diesel engine is equipped with an electronically controlled hydraulic system for variable actuation of the intake valves of the engine. The cam that controls each intake valve has an additional lobe for causing an additional opening of the intake valve, during the exhaust stroke, so as to provide an exhaust-gas recirculation directly inside the engine. Said additional lobe is shaped in such a way as to give rise to a profile of the additional lift of the valve as the crank angle varies with a boot conformation, including an initial stretch with a gentler slope extending from a point of zero lift corresponding to the expansion stroke in the engine cylinder. The engine is moreover equipped with a duct for exhaust-gas recirculation of the long-route type, which picks up the gases from a point of the exhaust duct set downstream of the catalytic converter and of the particulate trap.

Diesel engine having a system for variable control of the intake valves and internal exhaust-gas recirculation

A solenoid valve, particularly of the type to be used for controlling a hydraulic system for variable actuation of the valves of an internal-combustion engine, has a valve element co-operating with a valve seat and a pusher element, separate from the valve element, which is pushed against the valve element by the movable core of the solenoid valve when the solenoid of the solenoid valve is energized in order to bring the valve element into contact with the valve seat. After de-energization of the solenoid, the time necessary for bringing back the pusher element into the resting condition in contact with the valve element is reduced thanks to the application of a braking current to the solenoid of the solenoid valve during the stage in which the movable core and the pusher element associated thereto displace in the direction opposite to the direction of the movement generated by the magnetic field of the solenoid, following upon de-energization of the solenoid valve.

System and method for controlling a solenoid valve, particularly for a system for variable actuation of the valves of an internal combustion engine according to a multi-lift mode

An internal combustion engine is equipped with a variable actuation system for the intake valves, including a chamber of fluid under pressure interposed between the intake valve and the respective controlling cam, and a solenoid valve whose opening causes the pressure chamber to discharge such as to determine the rapid closure of the valve by effect of the respective biasing spring means, even when the respective cam would tend to keep the valve open. The variable valve operation system is used in combination with the use of cams controlling the intake valves shaped in such a manner as to give rise to an intake valve lift profile including a boot portion at substantially constant lift.

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Orbassano, Italy

Luca Gentile