Dual-pressure hydraulic valve-actuation system
AssigneeCummins Engine Company, Inc.
InventorsByron J. Bunker, Amarjit S. Ghuman, Rod Radovanovic, John M. Janssen
Life of this patent
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Abstract
A system and a method for hydraulic actuation of poppet valves. The poppet valve is opened by application of hydraulic pressure to a piston, and is closed by action of a mechanical spring. Hydraulic pressure comes from either a high pressure source of a low pressure source, the low pressure source being higher than ambient pressure. Application of hydraulic pressure is made by a pressure control device based upon signals received from an electronic controller. Hydraulic pressure is applied in a way that minimizes the power required to actuate the valve by making use of valve inertia.
Claims27
A method for hydraulically actuating a poppet valve between an opened position and a closed position, said method comprising the following steps:
- (a) providing fluid from a high pressure source of fluid to a cylinder, the cylinder containing a piston slidable therein, the piston operatively engaging the poppet valve;
- (b) moving of the poppet valve toward the opened position by the piston;
- (c) stopping the flow of fluid from the high pressure source to the cylinder;
- (d) flowing of fluid from a low pressure source of fluid into the cylinder through a first check valve, the low pressure source being at a pressure higher than ambient;
- (e) holding the poppet valve in a position by preventing flow of fluid out of the cylinder;
- (f) establishing fluid communication from the low pressure source of fluid to the cylinder;
- and
- (g) accelerating the poppet valve toward the closed position by a first return spring and a second return spring.
A system for hydraulically actuating a poppet valve between an opened position and a closed position, comprising:
- a first spring constructed and arranged for biasing the poppet valve to the closed position;
- a second spring constructed and arranged for biasing the poppet valve to the closed position, wherein said first spring and said second spring are arranged in series;
- a cylinder having an inlet;
- a piston slidably engaged in said cylinder, one side of said piston operatively engaged the poppet valve, and the opposite side of said piston forming a volume in said cylinder and being in fluid communication with the inlet;
- a source of high pressure fluid;
- a source of low pressure fluid, said low pressure source being at a pressure greater than ambient pressure;
- a controller for applying control signals;
- and
- a means for controlling cylinder pressure in response to control signals, and having a first fluid connection to said low pressure source, a second fluid connection to the inlet, and a third fluid connection to said high pressure source, whereby application of a first control signal puts the first and second fluid connections in fluid communication, and application of a second control signal puts the second and third fluid connections in fluid communication.
A method for hydraulically actuating a poppet valve between an opened position and a closed position, said method comprising the following steps:
- (a) providing fluid from a high pressure source of fluid to a cylinder, the cylinder containing a piston slidable therein, the piston operatively engaging the poppet valve;
- (b) moving of the poppet valve toward the opened position by the piston;
- (c) stopping the flow of fluid from the high pressure source to the cylinder;
- (d) reaccelerating of the poppet valve toward the opened position by providing fluid from the high pressure source to the cylinder;
- (e) holding the poppet valve in the opened position;
- (f) establishing fluid communication from the low pressure source of fluid to the cylinder;
- and
- (g) accelerating the poppet valve toward the closed position by a first return spring.
An apparatus for an internal combustion engine comprising:
- a cylinder head attached to the engine, said cylinder head having a valve seat;
- a hydraulically actuated poppet valve constructed and arranged for moving from a closed position to an opened position, wherein said poppet valve is in contact with said valve seat when said poppet valve is in the closed position, and said poppet valve is away from said valve seat when said poppet valve is in the opened position;
- a first spring for biasing said poppet valve to the closed position, said first spring constructed and arranged for being compressed;
- and
- a second spring for biasing said poppet valve to the closed position, said second spring constructed and arranged for being compressed;
- wherein said first spring and said second spring are arranged in series.
A method for hydraulically actuating a poppet valve between an opened position and a closed position, comprising:
- providing a poppet valve, a first spring, and a second spring;
- moving of the poppet valve from the closed position toward the opened position;
- compressing a first spring and a second spring by the movement of the poppet valve from the closed position toward the opened position;
- maintaining the first spring at a fixed compressed height during a portion of the movement of the poppet valve;
- and
- compressing only the second spring during said moving and after said maintaining.
A method for hydraulically actuating a poppet valve between an opened position and a closed position, said method comprising the following steps:
- (a) providing fluid from a high pressure source of fluid to a cylinder, the cylinder containing a piston slidable therein, the piston operatively engaging the poppet valve;
- (b) moving of the poppet valve toward the opened position by the piston;
- (c) stopping the flow of fluid from the high pressure source to the cylinder.
- (d) holding the poppet valve in a position by preventing flow of fluid out of the cylinder;
- (e) establishing fluid communication from a low pressure source of fluid to the cylinder the low pressure source being at a pressure higher than ambient pressure;
- and
- (f) accelerating the poppet valve toward the closed position by a first return spring and a second return spring the first return spring and the second return spring being in series.
Dependencies are inferred from the claim text.