Internal-combustion engine with cylinders that can be deactivated, in which the deactivated cylinders are used as pumps for recirculating the exhaust gases into the active cylinders, and method for controlling said engine

Abstract

In an internal-combustion engine provided with a system for variable actuation of the intake valves of the cylinders, some of said cylinders are deactivated in given conditions of operation of the engine by interrupting the supply of fuel. During de-activation, the cycle of opening and closing of the intake valves and exhaust valves of the deactivated cylinders is maintained. The intake valves of each deactivated cylinder are opened when the exhaust valves of the same cylinders are also open. The inactive cylinders are used as reciprocating volumetric pumps for recirculation of exhaust gases from the exhaust manifold of the engine up to the intake manifold. The recirculated gases are cooled in the intake manifold by the air introduced into the latter and can consequently be fed in a larger mass to the active cylinders, which enables a better global efficiency of the engine to be obtained.