Caterpillar Inc.

Kendall Dean Yeager

Victor Iskander Yacoub

Kevin James Schreader

Edwin Henry Langewisch

A valve actuation system is disclosed for an engine. The valve actuation system may have a variable valve actuator that is configured to engage a rocker arm and hold the valve at an open position regardless of motion of a cam lobe. The variable valve actuator may have a housing forming a chamber, a plunger disposed in the chamber, a control valve movable to control a flow of fluid into the chamber, and a relief valve configured to automatically open and release fluid from the housing when a pressure inside the chamber is below a predetermined pressure. The valve actuation system may further have a controller configured to cycle the control valve prior to start-up of the engine and to selectively move the control valve after start-up.

Variable valve actuator having low-pressure relief

A valve actuation system is provided. A fluid actuator is configured to selectively prevent a valve from moving to a particular position. A source of fluid is in fluid communication with the fluid actuator. A bi-directional control valve is configured to control a flow of fluid between the source of fluid and the fluid actuator. A fluid passageway connects the bi-directional control valve with the fluid actuator. A relief valve is in fluid communication with the fluid passageway and moveable between a closed position to prevent a flow of fluid therethrough to create a high pressure circuit in the valve actuation system and an open position to allow a flow of fluid therethrough to create a low pressure circuit in the valve actuation system.

Variable valve actuator

A system and a method for actuating intake valves of an internal combustion engine. The system includes a hydraulic circuit including a master cylinder, a control valve, an accumulator, a first one-way valve and a slave cylinder. The slave cylinder accommodates a slave piston, which is coupled to the intake valves. The control valve is disposed upstream of the accumulator for controlling flow from the hydraulic circuit to the accumulator. The first one-way valve is disposed downstream of the accumulator for permitting flow from the accumulator to the hydraulic circuit and for preventing flow from the hydraulic circuit to the accumulator without first passing through the control valve. The control valve has an open position that provides communication between the hydraulic circuit and the accumulator for a Miller cycle or Miller-like cycle operation. The control valve also has a closed position that prevents communication between the hydraulic circuit and the accumulator during Otto cycle operation.

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Palatine, IL, United States of America

Kendall Dean Yeager