Patent ID: 8662034
Filing Date: 2014-03-04
Classification: F01L,F02F

Abstract:
1. Multi-cylinder internal combustion engine, comprising, for each cylinder: at least one intake valve and at least one exhaust valve for each cylinder, each provided with respective return spring means which push the valve towards a closed position, for controlling respective intake and exhaust conduits, at least one camshaft, for actuating the intake valves of the engine cylinders by means of respective tappets, wherein each intake valve is controlled by the respective tappet, against the action of the aforementioned return spring means, by interposing hydraulic means including a pressurised fluid chamber and a hydraulic actuator associated to each intake valve and connected to said pressurised fluid chamber, said pressurised fluid chamber being adapted to be connected by means of a solenoid valve with an exhaust channel with the aim of decoupling the intake valve from the respective tappet and causing the quick closure of the valve due to the respective return spring means, said hydraulic actuator further being provided with hydraulic braking means for slowing the final phase of the travel for closing the intake valve controlled thereby when the pressure chamber is connected to the exhaust channel, electronic control means for controlling each solenoid valve so as to vary the time and/or the opening travel of the respective intake valve as a function of one or more engine operative parameters, wherein the hydraulic means for controlling the intake valves of the engine and the solenoid valves associated thereto are part of a preassembled unit mounted on the cylinder head of the engine, wherein the abovementioned pre-assembled unit is closed at the upper part by a cover having a base peripheral edge having a perimeter groove for mounting a sealing gasket, wherein said preassembled unit is formed by a plurality of separate sub-units respectively associated to the engine cylinders and having independent support bodies mounted on the cylinder head, so that each of said support bodies can be independently demounted from said cylinder head, wherein each of said sub-unit support bodies carries the hydraulic means and the solenoid valve controlling the at least one or intake valve of the respective cylinder, and wherein said sealing gasket has a main portion extending in a general plane for supporting the cover and respective portions associated to said sub-units and projecting from said general plane, in positions arranged longitudinally adjacent to each other on one side of the cylinder head and each having a three-dimensional development, with two lateral parts contained in two planes substantially parallel to each other and orthogonal to said general plane and a central part contained in a parallel plane and spaced from said base plane, so that sealing is ensured also in the area that separates each sub-unit from the one adjacent thereto.