C.r.f. Societa Consortile Per Azioni

Gianluca Canino

Francesco Vattaneo

Marco Cuniberti

Luca Gentile

Luca Iannarelli

Stefano Chiappini

Damiano Micelli

Laura Gianolio

Mario Durando

Rosario Nasto

Davide Peci

Maria Grazia Lisbona

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&#xb0;, without reducing the swirl ratio obtained at the end of the compression stage.

Combustion chamber for diesel engines with inclined engine valves

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.

Multi-cylinder internal combustion engine with a system for variable actuation of the intake valves subdivided into separate sub-units

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.

Diesel engine having a system for variable control of the intake valves and internal exhaust-gas recirculation

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.

Internal combustion engine with intake valves having a variable actuation and a lift profile including a constant lift boot portion

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. The first bushing of the auxiliary hydraulic tappet is positioned outside the guide bushing of the actuating piston, so that said bushing can be dimensioned with a relatively small diameter, regardless of the outer diameter of the auxiliary hydraulic tappet.

Internal combustion engine having valves with variable actuation each provided with a hydraulic tappet at the outside of the associated actuating unit

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.

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Orbassano, Italy

Gianluca Canino