Internal-combustion engine having a system for variable actuation of the intake values, provided with three-way solenoid valves, and method for controlling said engine in “single-lift” mode

Patent metadata

Field	Value
Publication number	US-9441509-B2
Application number	US-201414259189-A
Country	US
Kind code	B2
Filing date	Apr 23, 2014
Priority date	Apr 26, 2013
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

An internal-combustion engine includes a three-way, three-position solenoid valve, having an inlet communicating with a pressurized-fluid chamber and with a hydraulic actuator of an intake valve, and two outlets communicating with an actuator of another intake valve of a cylinder and the exhaust channel. The solenoid valve has a first position, in which the inlet communicates with both outlets, a second position, in which the inlet communicates only with the outlet connected to the actuator of the intake valve and a third position, in which the inlet does not communicate with any of the two outlets. During at least part of an active stroke of a tappet, the solenoid valve is kept in the third position to render the first intake valve active. During the active stroke of the tappet, the solenoid valve is never brought into the second position so that the second intake valve always remains closed.

First claim

What is claimed is:

1. An internal-combustion engine, comprising, for each cylinder:
a combustion chamber;
at least two intake ducts and at least one exhaust duct, which open out into said combustion chamber;
at least two intake valves and at least one exhaust valve, which are associated to said intake and exhaust ducts and are provided with respective return springs that push them into a closed position;
a camshaft for actuating the intake valves, by means of respective tappets;
wherein each intake valve of the intake valves is controlled by the respective tappet against the action of the return spring by interposition of hydraulic means including a pressurized-fluid chamber facing a pumping plunger connected to the tappet of the valve, said pressurized-fluid chamber being designed to communicate with the chamber of a hydraulic actuator associated to each intake valve of the intake valves;
a single solenoid valve, associated to the intake valves of each cylinder and designed to set in communication said pressurized-fluid chamber with an exhaust channel in order to decouple the intake valve from the respective tappet and cause fast closing of the intake valves as a result of the respective return springs; and
electronic control means, for controlling said solenoid valve so as to vary the instant of opening and/or the instant of closing and the lift of each intake valve of the intake valves as a function of one or more operating parameters of the engine,
the solenoid valve associated to each cylinder being a three-way, three-position solenoid valve, comprising:
an inlet permanently communicating with said pressurized-fluid chamber and with the actuator of a first intake valve of the intake valves; and
two outlets communicating, respectively, with the actuator of a second intake valve of the intake valves and with said exhaust channel,

said solenoid valve having the following three operating positions:
a first position, in which the inlet communicates with both of the outlets so that the pressurized-fluid chamber, the intake valves are both kept closed by their return springs;
a second position, in which the inlet communicates only with the outlet connected to the actuator of the second intake valve and does not communicate, instead, with the outlet connected to the exhaust channel, so that the pressure chamber is isolated from the exhaust channel, the actuators of both of the intake valves communicate with the pressure chamber, and the intake valves are hence both active; and
a third position, in which the inlet does not communicate with any of the two outlets, so that the aforesaid pressure chamber is isolated from the exhaust channel, and the aforesaid first intake valve is active, while the second intake valve is isolated from the pressure chamber and from the exhaust channel,

said electronic control means being programmed for implementing, in one or more given operating conditions of the engine, a mode of control of said solenoid valve, wherein:
during at least part of the active stroke of the tappet said electrically actuated valve is kept in said third position so as to render the first intake valve active, whereas, through the entire active stroke of the tappet, the electrically actuated valve is never brought into said second position so that said second intake valve always remains closed.

2. The engine according to claim 1 , wherein said solenoid valve comprises:
a valve body with a first mouth, a second mouth, and a third mouth, said first mouth comprising said inlet, and said second mouth and said third mouth comprising said outlets of said solenoid valve;
a first valve element and a second valve element that cooperate, respectively, with a first valve seat and with a second valve seat;
spring means tending to keep said first and second valve elements in an opening position, at a distance from the respective valve seats; and
a solenoid configured for being supplied with a first level of electric current or with a second level of electric current, to bring about, respectively, closing only of said first valve element against said first valve seat or closing of both of said first and second valve elements against the respective valve seats.

3. The engine according to claim 2 , wherein:
said first valve element and said first valve seat are prearranged for controlling the passage of fluid from said first mouth to said third mouth; and
said second valve element and said second valve seat are prearranged for controlling the passage of fluid from said first mouth to said second mouth.

4. The engine according to claim 3 , wherein said first and second valve elements share a same axis and are hydraulically balanced.

5. The engine according to claim 4 , wherein said second valve seat is defined on said first valve element.

6. The engine according to claim 1 , wherein said electronic control means are programmed for implementing, in one or more given operating conditions of the engine, a further mode of control of said solenoid valve in which the solenoid valve is brought into the third position at the start of the active phase of the respective tappet so as to cause initially only opening of said first intake valve and subsequently, in the course of said active phase of the tappet, said solenoid valve is brought into its second position so as to cause opening of said second intake valve with a delay with respect to opening of the first intake valve, said solenoid valve being kept in said second position up to the end of said active phase of the tappet.

7. The engine according to claim 2 , wherein said actuator is a solenoid, the spring means tending to keep said first and second valve elements in an opening position comprising two respective springs that are both set outside the solenoid, and in that inside the solenoid a solid fixed body is provided.

8. The engine according to claim 7 , wherein the solenoid cooperates with a mobile element, which has channels that enable communication of the pressure of the fluid that circulates in the valve on both sides of said mobile element so as to prevent any unbalancing.

9. The engine according to claim 7 , further comprising a tubular insert made of nonmagnetic material, guided within which is the mobile element co-operating with the solenoid, said insert being arranged within the solenoid in such a way that the lines of magnetic flux are forced to pass around the insert rendering the magnetic force that attracts said mobile element towards the solid fixed body maximum.

10. The engine according to claim 2 , further comprising an elastic retention ring that withholds the unit with the two valve elements inside the body of the control valve.

11. A method for controlling an internal-combustion engine, wherein said engine comprises, for each cylinder:
a combustion chamber;
at least two intake ducts and at least one exhaust duct, which open out into said combustion chamber;
at least two intake valves and at least one exhaust valve, which are associated to said intake and exhaust ducts and are provided with respective return springs that push them into a closed position;
a camshaft for actuating the intake valves, by means of respective tappets;
wherein each intake valve is controlled by the respective tappet against the action of the aforesaid return spring by interposition of hydraulic means including a pressurized-fluid chamber facing which is a pumping plunger connected to the tappet of the valve, said pressurized-fluid chamber being designed to communicate with the chamber of a hydraulic actuator associated to each intake valve;
a single solenoid valve, associated to the intake valves of each cylinder and designed to set in comm

Assignees

• Fiat Ricerche
• C R F Societá Consortile Per Azioni

Inventors

• Stucchi Sergio
• Ricco Raffaele
• De Michele Onofrio
• Gargano Marcello
• Altamura Chiara
• Mazzarella Carlo

Classifications

• F01L2001/3443

  Solenoid driven oil control valves · CPC title

• F01L13/0015 Primary

  for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque · CPC title

• F01L13/0005

  Deactivating valves · CPC title

• F01L2800/05

  Timing control under consideration of oil condition · CPC title

• F01L9/025

  Mechanical Engineering · mapped topic