Patent ID: 7819100
Filing Date: 2010-10-26
Classification: F01L,F02D,Y02T

Abstract:
1. A multi-cylinder internal combustion engine, including: at least one intake valve and at least one exhaust valve for each cylinder, each provided with respective biasing spring means that bias the valve to a closed position, to control the respective intake and exhaust conduits, at least one camshaft, to operate the intake valves and the exhaust valves of the cylinders of the engine through respective tappets, in which at least each intake valve is of the variable actuation type, by being controlled by a respective tappet, against the action of said biasing spring means, through the interposition of hydraulic means including a chamber of fluid under pressure, facing a pumping piston connected to the tappet of the valve, said chamber of fluid under pressure being adapted to be connected through a solenoid valve with a discharge channel, for the purpose of uncoupling the variable actuation valve from the respective tappet and causing the rapid closing of the valve under the action of the respective biasing spring means, electronic control means to control each solenoid valve so as to vary the time and extension (lift) of opening of the variable actuation valve as a function of one or more operating parameters of the engine, wherein the cam controlling each intake valve is shaped so as to generate a valve lift profile including a boot portion with substantially constant lift, wherein the engine is a supercharged petrol engine and wherein said boot portion of substantially constant lift is provided in the initial part of the intake valve lift cycle, in advance with regard to the top dead centre of the piston of the respective cylinder.