Actuator control system for bi-stable electric rocker arm latches
AssigneeEaton Intelligent Power Limited
InventorsPavel Kucera, Petr Liskar, Pavel Fojtik
Life of this patent
Estimating the term…
Abstract
An actuator control system suitable for providing single wire control of electromagnetic latch assemblies providing for cylinder deactivation or variable valve actuation in a valvetrain system. The system is adapted to control electromagnetic latch assemblies that require DC current in a first direction for latching and DC current in a reverse of the first direction for unlatching. The actuator control system includes an inverting DC/DC converter and switching elements. In some embodiments, the inverting DC/DC converter uses capacitors to store energy that drives the inverted current. In some embodiments, the inverting DC/DC converter serves a plurality of distinct groups of the electromagnets.
Claims17
A valvetrain for an internal combustion engine of a type that has a combustion chamber, a moveable valve having a seat formed in the combustion chamber, and a camshaft, the valvetrain comprising:
- a plurality of rocker arm assemblies, each comprising a rocker arm, a latch pin, and a cam follower configured to engage a cam mounted on a camshaft as the camshaft rotates;
- a plurality of electromagnets each having first and second terminals and each operative to actuate a distinct one of the latch pins;
- and
- an actuator control system comprising a first electronic device and one or more switching elements;
- wherein, when coupled to a DC power source, the actuator control system is operative to provide to the first terminals of any selected one of a plurality of distinct groups comprising one or more of the plurality of electromagnets a DC current that is selectively either in a first direction or a second direction;
- the second direction is a reverse of the first direction;
- the first electronic device is a device that when powered by a DC current having a first polarity is operative to provide a DC current having a second polarity, which is opposite that of the first polarity;
- the first electronic device provides the DC current in the second direction;
- the second terminals of the electromagnets are grounded;
- and
- the first electronic device comprises one or more capacitors operative to supply the DC current in the second direction.
A valvetrain for an internal combustion engine of a type that has a combustion chamber, a moveable valve having a seat formed in the combustion chamber, and a camshaft, the valvetrain comprising:
- a plurality of rocker arm assemblies, each comprising a rocker arm, a latch pin, and a cam follower configured to engage a cam mounted on a camshaft as the camshaft rotates;
- a plurality of electromagnets each having first and second terminals and each operative to actuate a distinct one of the latch pins;
- and
- an actuator control system comprising a first electronic device and one or more switching elements operative to provide the first terminal of one of the electromagnets with a DC current that is selectively in either a first direction or a second direction;
- wherein the second direction is a reverse of the first direction;
- the first electronic device comprises one or more capacitors operative to provide the DC current in the second direction;
- and
- the second terminals are grounded.
A method of operating electromagnets each having first and second terminals and each operative to actuate a distinct group of one or more latch pins in rocker arm assemblies in a valvetrain for an internal combustion engine of a type that has a combustion chamber, a moveable valve having a seat formed in the combustion chamber, and a camshaft, the method comprising:
- over a first period, coupling a DC power source to the first terminals of a first set of the electromagnets to provide a current in a first direction to those terminals;
- over a second period during which the DC power source is not coupled to the first terminals of the first set of the electromagnets, coupling the DC power source to the first terminals of a second set of the electromagnets, wherein the electromagnets in the second set are distinct from those in the first;
- storing energy from the DC power source in a first electronic device;
- over a third period, coupling the first electronic device to the first terminals of the first set of the electromagnets to provide a current in a second direction to those first terminals, wherein the second direction is a reverse of the first;
- over a fourth period during which the first electronic device is not coupled to the first terminals of the first set of the electromagnets, coupling the first electronic device to the first terminals of the second set of the electromagnets;
- and
- keeping the second terminals grounded over the first period, the second period, the third period, and the fourth period.
Dependencies are inferred from the claim text.