Abstract: An internal-combustion engine provided with a simplified system for variable actuation of the valves, which envisages for two different engine cylinders a single solenoid valve that controls connection to an exhaust channel of two pressurized chambers associated to the intake valves of the two different cylinders.

Abstract: 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.

Abstract: An internal-combustion engine provided with a simplified system for variable actuation of the valves, which envisages for two different engine cylinders a single solenoid valve that controls connection to an exhaust channel of two pressurized chambers associated to the intake valves of the two different cylinders.

Abstract: 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. Such boot portion is provided in the initial part of the intake valve opening cycle, in advance with regard to the TDC, in the case of a supercharged direct-injection petrol engine. In the case of a diesel engine, on the contrary, the boot portion is provided in the final part of the intake valve opening cycle, after the BDC.

Abstract: In a Diesel engine with variably actuated valves, the cam controlling each inlet valve is shaped to provoke the opening of the respective inlet valve during the engine's normal exhaust phase and thus realize exhaust gas recirculation within the engine, due to the fact that during the normal exhaust phase, part of the exhaust gas passes from the cylinder into the inlet port, from where it returns to the cylinder during the next induction phase, while part of the exhaust gas that had previously passed into the exhaust port returns to the cylinder during the induction phase due to the additional opening of the exhaust valve, in consequence of which the exhaust gas charges that return to the cylinder are subjected to further combustion in the next engine cycle.

Abstract: In a Diesel engine with variably actuated valves, the cam controlling each inlet valve is shaped to provoke the opening of the respective inlet valve during the engine's normal exhaust phase and thus realize exhaust gas recirculation within the engine, due to the fact that during the normal exhaust phase, part of the exhaust gas passes from the cylinder into the inlet port, from where it returns to the cylinder during the next induction phase, while part of the exhaust gas that had previously passed into the exhaust port returns to the cylinder during the said induction phase due to the additional opening of the exhaust valve, in consequence of which the exhaust gas charges that return to the cylinder are subjected to further combustion in the next engine cycle.

Abstract: In a Diesel engine with variably actuated valves, the cam controlling each inlet valve is shaped to provoke the opening of the respective inlet valve during the engine's normal exhaust phase and thus realize exhaust gas recirculation within the engine, due to the fact that during the normal exhaust phase, part of the exhaust gas passes from the cylinder into the inlet port, from where it returns to the cylinder during the next induction phase, while part of the exhaust gas that had previously passed into the exhaust port returns to the cylinder during the induction phase due to the additional opening of the exhaust valve, in consequence of which the exhaust gas charges that return to the cylinder are subjected to further combustion in the next engine cycle.