Caterpillar Inc.

Thomas S Carroll

Steven Francis Meister

David M Milam

Charles R Miller

Scott F Shafer

J Roger Weber

Chien Chang Lee

Gregory O Taylor

David R Orr

Chien-Chang Lee

An engine comprises a housing that defines a hollow piston cavity that is separated from a gas passage by a valve seat. The housing further defines a biasing hydraulic cavity and a control hydraulic cavity. A gas valve member is also included in the engine and is movable relative to the valve seat between an open position at which the hollow piston cavity is open to the gas passage and a closed position in which the hollow piston cavity is blocked from the gas passage. The gas valve member includes a ring mounted on a valve piece and a retainer positioned between the ring and the valve piece. A closing hydraulic surface is included on the gas valve member and is exposed to liquid pressure in the biasing hydraulic cavity.

Hydraulically actuated gas exchange valve assembly and engine using same

A fuel injector performs main fuel injection by raising fuel pressure in a nozzle chamber to lift a check valve member to a fully open position, and performs preinjection or microinjection by operating a solid state motor to lift the check valve member a much smaller distance.

Solid state lift for micrometering in a fuel injector

An actuator for opening a poppet exhaust valve, which is closed by a spring and opens in normal operation against a relatively low pressure and which opens for compression braking against a relatively high pressure, is motivated in either event by the same hydraulic pressure. The actuator has a unitary central valve and piston element, which is coaxially directed toward the exhaust valve stem and has an area providing, when subjected to the pressure, a force sufficient to open the exhaust valve for normal operation but insufficient to open the exhaust valve during compression braking. The element extends through a relatively larger diameter annular piston which is slidably fitted about the element and within a bore receiving the annular piston. In normal operation, the element provides enough force to move from an unactuated position and open the exhaust valve, and initial movement of the element closes off passages in the element that admit the pressure to the piston which thus does not move. During compression braking, the force developed by the central element cannot move the element and the exhaust valve so that these passages admit pressure to the piston which provides sufficient force to move with the central element and open the exhaust valve. In either event, when the hydraulic pressure is subsequently reduced, the spring closes the exhaust valve and returns the actuator to its unactuated position. The actuator may be constructed to provide a smaller valve opening for braking than for normal operation.

Camless valve actuator for compression braking and normal engine operations

A servo control valve includes a valve body that defines a high pressure passage, a low pressure passage and a flow passage. A valve member has a first pressure surface in opposition to a control pressure surface. The valve member is positioned in the valve body and moveable between a first position in which the high pressure passage is open to the flow passage, and a second position in which the low pressure passage is open to the flow passage. A pilot member is positioned in the valve body and is moveable between an up position in which the control pressure surface is exposed to pressure in the high pressure passage, and a down position in which the control pressure surface is exposed to pressure in the low pressure passage. A spring is operably positioned to bias a valve member toward one of its first position and its second position.

Servo control valve for a hydraulically-actuated device

The present invention is an apparatus 10 for hydraulically slowing a member (12), preferably an engine poppet valve, to an acceptable impact seating velocity as the valve (12) is moved from open to closed. The poppet valve (12) has a stem (16) having a first portion (18) connected through a stepped portion (20) to a second portion (22) having a greater cross-sectional area than the first portion (18). The valve (12) rides within a guide body (28) having an opening (34) in an end wall (32) thereof through which the first portion (18) of the stem (16) extends. A hydraulic fluid space (50) is formed by the guide body (28) and the valve (12). As the valve (12) closes, fluid is forced out of the space (50) through a first fluid exit opening (66). As the valve (12) nears its seat (44), the fluid still in the space (50) is forced out through a second fluid exit opening (68) through which the rate of flow is less than the rate of flow through the first fluid exit opening (66). As the valve (12) continues closing, fluid still in the space (50) is compressed, increasing its hydraulic pressure and creating a resistive force to further movement of the poppet valve (12), thereby slowing it to an acceptable impact velocity.

Growing community of inventors

Peoria, IL, United States of America

Thomas S Carroll