Abstract: A motor vehicle provided with an internal combustion engine having a system for variable actuation of the intake valves has a phase of activation of an operating mode with the engine off and the vehicle moving, in which the fuel supply to the engine is cut-off. After the cut-off of the fuel supply to the engine, the system for variable actuation of the intake valves is controlled to vary the opening time and/or closing time and/or the lift of the intake valves so as to control the losses due to the pumping effect which occur within the engine in cut-off condition.

Abstract: A spark-ignition supercharged internal-combustion gasoline engine is equipped with a system for variable actuation of the intake valves including a pressurized fluid chamber set between intake valve and a respective control cam, and an electrically actuated valve, the opening of which vents the pressure chamber so as to cause rapid closing of the valve, as a result of the respective elastic return means, even when the respective cam would tend to keep the valve open. The variable-valve-actuation system is used in combination with control cams of the intake valves shaped in such a way as to generate an intake valve lift profile including a boot portion with substantially constant lift. The boot portion is provided in the final part of the opening cycle of the intake valve, after bottom dead center.

Abstract: In a vehicle provided with a power propulsion system of the mild-hybrid type, a BAS unit—including an electric machine connected through a belt transmission to the shaft of an internal combustion engine—is exploited as the only propulsion engine of the vehicle in given operating conditions. The internal combustion engine is provided with a system for variable actuation of the intake valves which is controlled to reduce the pumping losses of the internal combustion engine in the phase in which such engine is in cut-off condition and it is driven by the aforementioned BAS unit. It is also provided for that the system for variable actuation of the intake valves be controlled to temporarily increase the pumping losses of the internal combustion engine in a phase in which it is required to accelerate the switching off of the 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.

Abstract: A multi-cylinder internal combustion engine is provided with a system for the variable actuation of the intake valves, and such system is used to vary the amount of air taken in by each cylinder so as to reduce to the minimum or entirely eliminate the differences in the torque produced by the various cylinders and hence limit the irregularities in the rotation speed of the engine shaft.

Abstract: A multi-cylinder internal combustion engine is provided with a system for the variable actuation of the intake valves. At least one part of the engine cylinders is deactivated, cutting off fuel supply to said cylinders, under operating conditions that do not require the maximum power of the engine and in which one wants to reduce fuel consumption. The intake valves of the deactivated cylinders are kept at least partly open during at least one part of the discharge stages in the deactivated cylinders, hence, in the deactivated cylinders, part of the burnt gases generated during the operation prior to the deactivation flows into the respective intake conduits during the discharge stage of each cylinder. The intake valves are closed after the discharge stage. The intake valves of the deactivated cylinders are further kept closed during the compression and expansion stages in each deactivated cylinder.

Abstract: A spark-ignition supercharged internal-combustion gasoline engine is equipped with a system for variable actuation of the intake valves including a pressurized fluid chamber set between intake valve and a respective control cam, and an electrically actuated valve, the opening of which vents the pressure chamber so as to cause rapid closing of the valve, as a result of the respective elastic return means, even when the respective cam would tend to keep the valve open. The variable-valve-actuation system is used in combination with control cams of the intake valves shaped in such a way as to generate an intake valve lift profile including a boot portion with substantially constant lift. The boot portion is provided in the final part of the opening cycle of the intake valve, after bottom dead center.

Abstract: An electronic control means of an engine controls a system for the variable actuation of intake valves and for controlling gasoline injection into the combustion chamber. To the electronic control means there are associated memory means. The electronic means are programmed for detecting a value of a crank angle at which the intake valve is closed, controlling the end of the injection with an anticipation with respect to the closing of the intake valve controlling the start of the injection substantially according to said crank angle limit value, and regulating the injection pressure to a value which is defined as a function of the injection time to guarantee the injection of a predefined amount of gasoline.

Abstract: A motor vehicle provided with an internal combustion engine having a system for variable actuation of the intake valves has a phase of activation of an operating mode with the engine off and the vehicle moving, in which the fuel supply to the engine is cut-off. After the cut-off of the fuel supply to the engine, the system for variable actuation of the intake valves is controlled to vary the opening time and/or closing time and/or the lift of the intake valves so as to control the losses due to the pumping effect which occur within the engine in cut-off condition.

Abstract: In a vehicle provided with a power propulsion system of the mild-hybrid type, a BAS unit —including an electric machine connected through a belt transmission to the shaft of an internal combustion engine—is exploited as the only propulsion engine of the vehicle in given operating conditions. The internal combustion engine is provided with a system for variable actuation of the intake valves which is controlled to reduce the pumping losses of the internal combustion engine in the phase in which such engine is in cut-off condition and it is driven by the aforementioned BAS unit. It is also provided for that the system for variable actuation of the intake valves be controlled to temporarily increase the pumping losses of the internal combustion engine in a phase in which it is required to accelerate the switching off of the 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.

Abstract: A multi-cylinder internal combustion engine is provided with a system for the variable actuation of the intake valves, and such system is used to vary the amount of air taken in by each cylinder so as to reduce to the minimum or entirely eliminate the differences in the torque produced by the various cylinders and hence limit the irregularities in the rotation speed of the engine shaft.

Abstract: An electronic control means of an engine controls a system for the variable actuation of intake valves and for controlling gasoline injection into the combustion chamber. To the electronic control means there are associated memory means. The electronic means are programmed for detecting a value of a crank angle at which the intake valve is closed, controlling the end of the injection with an anticipation with respect to the closing of the intake valve controlling the start of the injection substantially according to said crank angle limit value, and regulating the injection pressure to a value which is defined as a function of the injection time to guarantee the injection of a predefined amount of gasoline.

Abstract: A multi-cylinder internal combustion engine is provided with a system for the variable actuation of the intake valves. At least one part of the engine cylinders is deactivated, cutting off fuel supply to said cylinders, under operating conditions that do not require the maximum power of the engine and in which one wants to reduce fuel consumption. The intake valves of the deactivated cylinders are kept at least partly open during at least one part of the discharge stages in the deactivated cylinders, hence, in the deactivated cylinders, part of the burnt gases generated during the operation prior to the deactivation flows into the respective intake conduits during the discharge stage of each cylinder. The intake valves are closed after the discharge stage. The intake valves of the deactivated cylinders are further kept closed during the compression and expansion stages in each deactivated cylinder.

Abstract: Internal combustion engine with variable actuation of the valves that provides electronic control means that considers the activation delays of the cylinders so that new operating conditions are assigned for the first time to a cylinder which firstly, following an engine operating variation request, is effectively able to satisfy such new operating conditions.

Abstract: Internal combustion engine with variable actuation of the valves providing electronic control means which, when the engine is subject to an operating variation request from a first operating condition to a second operating condition, are adapted to select a cylinder to which to assign said second operating condition based on a determined programming delay only as a function of the engine speed.

Abstract: Internal combustion engine with variable actuation of the valves that provides electronic control means that considers the activation delays of the cylinders so that new operating conditions are assigned for the first time to a cylinder which firstly, following an engine operating variation request, is effectively able to satisfy such new operating conditions.

Abstract: Internal combustion engine with variable actuation of the valves providing electronic control means which, when the engine is subject to an operating variation request from a first operating condition to a second operating condition, are adapted to select a cylinder to which to assign said second operating condition based on a determined programming delay only as a function of the engine speed.

Abstract: An internal-combustion engine, comprises at least one cylinder, at least one intake pipe and at least one exhaust pipe associated to the cylinder, at least one intake valve and at least one exhaust valve, which control passage through the intake and exhaust pipes, wherein there are provided first sensor device(s) for detecting the temperature in the intake pipe, second sensor device(s) for detecting the pressure in the intake pipe, third sensor device(s) for detecting the engine r.p.m., and fourth device(s) for detecting or calculating the temperature in the exhaust pipe. An electronic control unit pre-arranged for receiving the signals at output from the first second and third sensor device(s) calculates the amount of fresh air taken in by the engine on the basis of a mathematical model that is of general applicability and that, in particular, is applicable irrespective of the technological implementation specifically used for a system for variable valve actuation with which the engine can be provided.

Abstract: In an internal-combustion engine, comprising at least one cylinder, at least one intake pipe and at least one exhaust pipe associated to the cylinder, at least one intake valve and at least one exhaust valve, which control passage through said intake and exhaust pipes, there are provided first sensor means for detecting the temperature in said intake pipe, second sensor means for detecting the pressure in said intake pipe, third sensor means for detecting the engine r.p.m., and fourth means for detecting or calculating the temperature in said exhaust pipe. An electronic control unit pre-arranged for receiving the signals at output from said first, second and third sensor means calculates the amount of fresh air taken in by the engine on the basis of a mathematical model that is of general applicability and that, in particular, is applicable irrespective of the technological implementation specifically used for a system for variable valve actuation with which the engine can be provided.