Patent ID: 8447499

Claim:
A diesel engine comprising: at least one intake valve for each cylinder, provided with elastic return means that push the valve towards a closed position; and at least one camshaft for controlling the intake and exhaust valves, by means of respective tappets, wherein at least one intake valve for each cylinder is controlled by the respective tappet, against the action of the aforesaid elastic means, by interposition of hydraulic means including a pressurized fluid chamber, wherein said pressurized fluid chamber is designed to be connected by means of a passage controlled by a solenoid valve with an exhaust channel, so that when the solenoid valve is open, the intake valve is uncoupled from the respective tappet and is kept closed by said elastic means, there being associated to said engine electronic control means for controlling each solenoid valve in such a way as to vary the time and/or the stroke of opening of the respective intake valve as a function of the operating conditions of the engine, wherein the cam for controlling said intake valve has a main lobe for causing opening of the intake valve during the induction stroke for intake of fuel into the engine cylinder, and an additional lobe for causing an additional opening of the intake valve during the exhaust stroke, the additional lobe has a 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 (C) corresponding to a substantially non-zero value of the lift that radiuses the descending stretch of the profile (B) of the additional lift to the ascending stretch of the profile (A) of the main lift, said portion (C) being an extended stretch corresponding a substantially constant lift through a substantial crank rotation between the end of the additional profile (B) and the start of the main profile (A).