Abstract: A new architecture of a combustion chamber for a diesel engine allows arranging the engine valves according to an axis inclined with respect to the cylinder axis by an angle greater than 8°, without reducing the swirl ratio obtained at the end of the compression stage.

Abstract: An engine comprises a system for variable actuation of the intake valves and is subdivided into a plurality of sub-systems independent with respect to each other, carried by a plurality of respective elements, each mounted on the cylinder head at a respective engine cylinder. Among other things, this considerably facilitates the system maintenance operations.

Abstract: In a multi-cylinder internal combustion engine, provided with a system for variable actuation of the intake valves of the engine, the fuel injector associated to each engine cylinder is surrounded by a sealing casing which is part of a support body. The support body is mounted on the engine cylinder head with the interposition of a support surmounting the head and defining the seat in which the camshaft is received and it defines a sealing peripheral edge cooperating with a sealing cover which is mounted on the cylinder head. The cover has a general base plane sealingly mounted on the cylinder head or on the support. The sealing peripheral edge of each sealing casing is arranged in a parallel plane and raised with respect to the general base plane of the cover.

Abstract: An engine comprises a system for variable actuation of the intake valves and is subdivided into a plurality of sub-systems independent with respect to each other, carried by a plurality of respective elements, each mounted on the cylinder head at a respective engine cylinder. Among other things, this considerably facilitates the system maintenance operations.

Abstract: A new architecture of a combustion chamber for a diesel engine allows arranging the engine valves according to an axis inclined with respect to the cylinder axis by an angle greater than 8°, without reducing the swirl ratio obtained at the end of the compression stage.

Abstract: A supercharged diesel engine is equipped with an electronically controlled hydraulic system for variable actuation of the intake valves of the engine. The cam that controls each intake valve has an additional lobe for causing an additional opening of the intake valve, during the exhaust stroke, so as to provide an exhaust-gas recirculation directly inside the engine. Said additional lobe is shaped in such a way as to give rise to a profile of the additional lift of the valve as the crank angle varies with a boot conformation, including an initial stretch with a gentler slope extending from a point of zero lift corresponding to the expansion stroke in the engine cylinder. The engine is moreover equipped with a duct for exhaust-gas recirculation of the long-route type, which picks up the gases from a point of the exhaust duct set downstream of the catalytic converter and of the particulate trap.

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: A supercharged diesel engine is equipped with an electronically controlled hydraulic system for variable actuation of the intake valves of the engine. The cam that controls each intake valve has an additional lobe for causing an additional opening of the intake valve, during the exhaust stroke, so as to provide an exhaust-gas recirculation directly inside the engine. Said additional lobe is shaped in such a way as to give rise to a profile of the additional lift of the valve as the crank angle varies with a boot conformation, including an initial stretch with a gentler slope extending from a point of zero lift corresponding to the expansion stroke in the engine cylinder. The engine is moreover equipped with a duct for exhaust-gas recirculation of the long-route type, which picks up the gases from a point of the exhaust duct set downstream of the catalytic converter and of the particulate trap.

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 an internal combustion engine with variable actuation valves, each variable actuation valve is actuated by an actuator assembly including an actuating piston slidably mounted in a guide bushing. Between the actuating piston and the stem of the respective valve is interposed an auxiliary hydraulic tappet comprising a first bushing and a second bushing positioned inside the first bushing in such a way as to define a first chamber between the second bushing and the actuating piston, and a second chamber between the two bushings of the hydraulic tappet. The first chamber is fed a pressurized chamber of the engine lubrication loop. A check valve controls a communication between the two chambers of the tappet, to allow the passage of fluid in the direction of the second chamber.

Abstract: An internal-combustion engine has a cylinder head, in which two shafts are mounted rotating. A first shaft is a camshaft, equipped both with cams that control the intake valves by means of an electronically controlled hydraulic device and with cams that control the exhaust valves mechanically. The second shaft is without cams and has an end coming out of the engine and constituting a power take-off for control of auxiliary service devices. The engine can be obtained with simple operations starting from an engine of a conventional type.

Abstract: An internal-combustion engine has a cylinder head, in which two shafts are mounted rotating. A first shaft is a camshaft, equipped both with cams that control the intake valves by means of an electronically controlled hydraulic device and with cams that control the exhaust valves mechanically. The second shaft is without cams and has an end coming out of the engine and constituting a power take-off for control of auxiliary service devices. The engine can be obtained with simple operations starting from an engine of a conventional type.

Abstract: In an internal combustion engine with variable actuation valves, each variable actuation valve is actuated by an actuator assembly including an actuating piston slidably mounted in a guide bushing. Between the actuating piston and the stem of the respective valve is interposed an auxiliary hydraulic tappet comprising a first bushing and a second bushing positioned inside the first bushing in such a way as to define a first chamber between the second bushing and the actuating piston, and a second chamber between the two bushings of the hydraulic tappet. The first chamber is fed a pressurised chamber of the engine lubrication loop. A check valve controls a communication between the two chambers of the tappet, to allow the passage of fluid in the direction of the second chamber.