Efficient internal combustion engine valve actuator
AssigneeCaterpillar Inc.
InventorsScott A. Leman, Sean O. Cornell
Life of this patent
Estimating the term…
Abstract
An engine with an efficient valve actuator is disclosed. The engine employs a first force to hold a valve of the engine open during a normal valve event and a second force to hold the exhaust valve open during an exhaust gas recirculation event. The valve actuator may be operated using pressurized fluid adapted to extend an actuator plunger through a cylinder. The first force may be derived by a mechanically driven actuator, while the second force may be derived from a high pressure rail of the engine. A control valve may be employed to direct either low pressure or high pressure oil to the valve actuator cylinder.
Claims31
An engine valve assembly, comprising:
- an engine valve seat;
- an engine valve element adapted to move relative to the valve seat between an open position and a closed position;
- and
- an actuator operatively associated with the valve element and adapted to impart a first force having a first magnitude to the valve element, and a second force having a second magnitude greater than said first magnitude to the valve element to move the valve element.
An engine valve actuator, comprising:
- an actuator cylinder;
- an actuator piston reciprocatingly mounted in the actuator cylinder, the actuator piston including a rod operatively associated therewith;
- a first source of pressurized fluid;
- a second source of pressurized fluid, the second source being pressurized at a higher pressure than the first source;
- and
- a control valve in fluid communication with the first source, the second source, and the actuator cylinder, the control valve having a first position and a second position, said first position connecting the first source in fluid communication with the actuator cylinder, said second position connecting the second source in fluid communication with the actuator cylinder.
An engine, comprising:
- an engine cylinder;
- an engine piston reciprocatingly disposed in the engine cylinder;
- a valve element disposed in a port of the engine cylinder;
- a valve actuator connected to the engine and positioned proximate the valve stem;
- a first source of pressurized fluid in fluid communication with the valve actuator;
- a second source of pressurized fluid in fluid communication with the valve actuator;
- and
- a control valve adapted to control flow of pressurized fluid from the first and second sources of pressurized fluid to the valve actuator.
A method of controlling an engine, comprising the steps of:
- providing an engine having an engine cylinder, a valve port extending from the engine cylinder, and a valve element adapted to move between and open and closed positions relative to the valve port;
- opening the valve with a first force derived from a first source;
- holding the valve in the open position with a second force derived from a second source;
- expelling exhaust gas from the engine cylinder during the opening step;
- and
- drawing exhaust gas into the engine cylinder during the holding step.
Dependencies are inferred from the claim text.