Abstract: An example system for isolating cement slurry from drilling fluids includes a tool configured for installation on a landing collar of a casing. The tool includes a base that conforms to an inner circumference of the casing and a tube that extends uphole from the base. The tube has a first borehole that extends downhole through the base. The tube is perforated to allow cement slurry to pass from the casing into the first borehole. A cementing plug is configured to seal to the casing uphole of the base. The cementing plug includes a second borehole to receive the tube. The cementing plug includes a covering that extends across at least part of the borehole and that is configured to break in response to contact with the tube.

Abstract: A system and method of controlling a dynamic time-pressure profile associated with a perforation event that includes extending a perforation assembly within a casing string; firing a perforation gun of the perforation assembly; measuring, using a sensor of the perforation assembly, pressure within the casing string, wherein the measured pressure forms the dynamic time-pressure profile; identifying a first measured pressure within the dynamic time-pressure profile; identifying, using a controller of the perforation assembly, a first difference between the first measured pressure and a first reference pressure; and adjusting, using a first pressure generator of the perforation assembly, the pressure in response to the first difference to control the dynamic time-pressure profile; wherein the sensor, the controller, and the first pressure generator provide a feedback control loop.

Abstract: A hydraulic port collar includes a housing having one or more housing ports. The hydraulic port collar includes a port collar bore disposed within the housing forming an inner surface of the housing. The hydraulic port collar includes a sliding sleeve disposed within the port collar bore. The sliding sleeve has a sliding sleeve inner surface and a sliding sleeve outer surface. The hydraulic port collar includes a dissolvable or fragmentable landing seat radially aligned with and abutting the sliding sleeve inner surface.

Abstract: A system for controlling fluid flow in a subterranean well includes a first valve, a control line fluidly coupled to the first valve, an equalizing line disposed externally to and separate from the first valve, and at least a second valve disposed in the equalizing line and in fluid communication with the control line. The first valve includes a body defining a lumen, and an upper portion, and a lower portion. The equalizing line is in fluid communication with the lumen between the upper portion and the lower portion of the body. The second valve equalizes a pressure between the upper and lower portions of the body.

Abstract: An exemplary embodiment includes a system to determine which wells provide input volumes to gas processing plants using a mixed-integer programming (MIP) model. The system uses a balanced approach to model all plants and wells within a basin simultaneously. The model utilizes multiple publically available data sources including well production data, plant inlet data, and GIS data. The full implementation provides at minimum a tenfold time improvement over the previously used manual techniques while increasing overall model quality.

Abstract: A drilling or work-over vessel (10) is disclosed comprising a number of operational equipment (300), wherein the drilling or work-over vessel comprises at least one operational control and/or state unit (100) comprising at least one processing unit (102), wherein the at least one operational control and/or state unit (100) comprises or are in connection with a memory and/or storage (103), and at least one sensor unit (200), wherein the at least one sensor unit (200) is adapted to obtain one or more measured physical values and to provide data representing the one or more measured physical values and/or derived values thereof to the at least one operational control and/or state unit (100), the memory and/or storage (103) comprises a data representation of a computational physics model of at least a part of the drilling or work-over rig, and the at least one processing unit (102) is adapted to derive data representing an estimation of one or more physical states (such as defined by limits of forces, relative mo

Abstract: In accordance with embodiments of the present disclosure, systems and methods for triggering detonation of a perforating gun via optical signals are provided. An improved laser firing head may be used with an optical cable (e.g., fiber optic cable) run through the wellbore to trigger detonation of a perforating gun in response to an optical signal. The laser firing head may be activated, and the perforating gun fired, upon the application of an optical signal output from the surface and transmitted through the optical cable. The disclosed system using the laser firing head with the optical cable may be impervious to electrical interference, since the laser firing head may only fire the perforating gun when a properly modulated laser or light source is directed down the optical cable for a specific period of time.

Abstract: Methods and systems for restimulating a previously fractured subterranean formation penetrated by a wellbore are described. The methods include plugging existing perforations in an outer casing and existing fractures in the formation with a diverting agent, placing an inner casing in the wellbore while the existing perforations and existing fractures are plugged with the diverting agent, perforating the inner casing and the outer casing to form new perforations, and pumping a fluid through the new perforations to create new fractures in the formation.

Abstract: A production tubing is disposed in a wellbore formed in a subterranean zone. The production tubing extends from a surface of the wellbore to a downhole location at which hydrocarbons entrapped in the subterranean zone enter the wellbore. Multiple valves are disposed in the production tubing at respective multiple tubing locations. Each valve is configured to permit one-way flow of hydrocarbons in an uphole direction. The multiple valves divide the production tubing into multiple stages. A stage is a portion of the production tubing between two successively disposed valves. Multiple gas injection valves are coupled to the production tubing and are disposed in a respective stage. A controller, coupled to the multiple valves and the multiple gas injection valves, transmits signals to the multiple valves and the multiple gas injection valves to lift hydrocarbons flowed into the wellbore at the downhole location to the surface on a stage-by-stage basis.

Abstract: Provided is a multi-functional well completion apparatus and method of operation thereof that offers the ability, in a single trip and with limited running tool manipulation, to perform a sand control frac or other fluid stimulation operation and reverse out operations that has improved reverse out flow rates. Furthermore, a combination of dropped balls and hydraulic pressure open one or more sleeves for selective access to a plurality of isolated zones. Additionally, a combination of concentric pipe and internal flow paths creates a reverse flow path. This reverse flow path provides a live annulus during treating, the ability to take returns, and the ability to reverse excess proppant from the wellbore.

Abstract: A long-distance drilling and hydrofracturing integrated device and method in underground mine are provided. The device includes a drill bit, a hydrofracturing rod, an anti-impact rod, a hole sealing rod, a high-pressure sealed drill rod and a crawler drill rod feeder sequentially connected end to end. In the method, the drill rod and the hydrofracturing rod are delivered to a designated position while drilling, the drill rod does not need to be taken out, only a crawler drill needs to be improved, high-pressure water holes are added to the rod feeder, and the high-pressure water enters the drill rod from the high-pressure water holes and reaches the hydrofracturing portion. When the hydrofracturing is completed, the drill rod is withdrawn by the crawler drill, reaches another hydrofracturing point, and a hole sealing operation can also be performed.

Abstract: Methods and systems are presented in this disclosure for evaluating whether to apply fluid flowback during a fracture closure stage of a hydraulic fracturing operation of a reservoir formation. Information collected prior to the fracture closure stage of the hydraulic fracturing operation can be first gathered. Based on the collected information, it can be determined whether to perform fluid flowback during the fracture closure stage following a treatment stage of the fracturing operation. Based on the determination, a rate of the fluid flowback can be adjusted and optimized in real-time during the fracture closure stage.

Abstract: A vapor recovery apparatus degasses oil and water produced by an oil well. The apparatus has a first vessel forming a column. Oil containing gas enters the bottom of the first vessel and flows up to a liquid outlet. Heat applied to the rising oil, wherein the oil foams. Gas escapes into the upper end. The foam flows into a second column and along a roughened surface. The bubbles in the foam break apart releasing the gas. The oil flows down the second column to an outlet. Water is introduced into a third vessel. The water releases gas therein, which gas mingles with the gas from the oil. The third vessel is located around the first and second vessels. A compressor may be used to withdraw the gas and provide hot compressed gas to heat the rising oil in the first column.

Abstract: The present disclosure describes methods and systems for downhole well integrity reconstruction in a hydrocarbon reservoir. One method for downhole well integrity reconstruction in a hydrocarbon reservoir includes: positioning, a laser head at a first subterranean location, wherein the laser head is attached to a tubular inside of a wellbore; directing, by the laser head, a laser beam towards a leak on the wellbore; and sealing the leak using the laser beam.

Abstract: A method includes obtaining a sample of a fluid from a subterranean zone while the fluid is being extracted from the zone. A chemical composition of the sample is measured. A temperature and a pressure of the subterranean zone are measured. The measured properties are associated with a time point. The measured properties are incorporated into a set of historical data. A chemical composition of a fluid to be extracted from the subterranean zone at a future time point is determined based on the set of historical data. A presence of a liquid phase in the fluid to be extracted from the subterranean zone at the future time point is determined. A flow rate of the fluid being extracted from the subterranean zone is adjusted in response to determining the presence of the liquid phase in the fluid to be extracted from the subterranean zone at the future time point.

Abstract: A method of investigating an earth formation. A tool having a pressure sensor is used in a borehole to collect formation fluid pressure data over time. A pressure derivative curve is generated from the formation fluid pressure data by conducting a piecewise linear regression of the data having optimal window length values L determined by calculating a derivative with respect to L of a pressure derivative value (DD), and selecting values of L where DD has a transition that departs from oscillatory behavior to gradual change. The pressure derivative is calculated with piecewise linear regression with the optimal window length values 2L. Different L values are generated for different groups of data points obtained over time. The pressure derivative is then used for flow regime determination.

Abstract: A matrix production logging tool for measuring the temperature of produced fluids in a wellbore is described. Accurate production allocation to the pathways between the oil/gas well and the reservoir provides required data for the economic optimization of the techniques and procedures used to complete future wells and optimize the existing well. The low maintenance tool provides precise uphole, downhole and inflow temperature measurements of produced fluids within the wellbore. These are obtained at a plurality of locations along the oil/gas well as the tool is withdrawn, thus providing a matrix of temperature measures along the length of the well. From the temperature traces, inflow as well as up and downhole temperature, can be determined, and mass contribution at each inlet determined. With this method, a production profile along the entire well can be determined as used in further well optimization efforts.

Abstract: This disclosure includes methods for testing hydraulically-actuated devices and related systems. Some hydraulically-actuated devices have a housing defining an interior volume and a piston disposed within the interior volume and dividing the interior volume into a first chamber and a second chamber, where the piston is movable relative to the housing between a maximum first position and a maximum second position in response to pressure differentials between the first and second chambers. Some methods include: (1) moving the piston to the first position by varying pressure within at least one of the first and second chambers such that pressure within the second chamber is higher than pressure within the first chamber; and (2) while the piston remains in the first position: (a) reducing pressure within the second chamber and/or increasing pressure within the first chamber; and (b) increasing pressure within the second chamber and/or decreasing pressure within the first chamber.

Abstract: An example tool for testing a wellbore includes a body having a longitudinal dimension configured for insertion into a casing of the wellbore, and a packer disposed along the body. The packer is controllable to expand against an inner diameter of the casing to enable testing the wellbore. The example tool also includes a scraper assembly disposed along the body for arrangement downhole of the packer when the body is inserted into the casing.

Abstract: A set of instructions stored on at least one non-transitory computer readable medium running on a computer system having at least one processor. The set of instructions extract outputs from sensors of a measurement while drilling system of a drilling rig; enable a transmitter to transmit a first data stream having at least one data series including drilling data, the first data stream having an interruptible portion encompassing at least a portion of the drilling data; detect a trigger event during transmission of the first data stream; and cease transmission of the first data stream.

Abstract: A complete telemetry system and methods for downhole operations. The telemetry system includes an instrumented near-bit sub located below the Mud Motor and connected to the drill bit as well as a conventional MWD tool located above the mud motor. Parameters such as inclination of the borehole, the natural gamma ray of the formations, the electrical resistivity of the formations, and a range of mechanical drilling performance parameters are measured. Electromagnetic telemetry signals representing these measurements are transmitted uphole to a receiver associated with the conventional MWD tool located above the motor, and transmitted by this tool to the surface via mud pulse signals. The system is particularly useful for accurate control over the drilling of extended reach and horizontally drilled wells.

Abstract: Systems and methods for terahertz modulation in a terahertz frequency band from about 0.1 terahertz to about 10 terahertz propagating in a wellbore intersecting a subterranean earth formation. A transmitter generates the EM radiation in the terahertz frequency band. A modulator located in the wellbore receives the EM radiation and generates an amplitude modulated signal with the EM radiation.

Abstract: A non-rotatable, downhole imaging tool, an imaging system including the non-rotatable imaging tool and methods of determining information about a wellbore employing the non-rotatable imaging tool are provided herein. One example of a non-rotatable imaging tool is disclosed that has a central axis and horizontal planes perpendicular to the central axis, and further includes: (1) a radiation detector positioned proximate the central axis and uniquely on one of the horizontal planes, and (2) a collimator configured to limit exposure of the radiation detector to a single azimuthal area along a circumference of the downhole imaging tool on the one of the horizontal planes.

Abstract: Fluid properties like viscosity, yield strength, and density may be measured by analyzing fluid motion in response to disturbing the surface of the fluid. For example, a method may include disturbing a surface of a fluid in one or more locations, thereby forming a deformation and waves at the surface of the fluid for the one or more locations; imaging and measuring at least one selected from the group consisting of the deformation, the waves, and a combination thereof; and calculating a property of the fluid based on the at least one selected from the group consisting of the deformation, the waves, and a combination thereof, the property selected from the group consisting of viscosity, yield strength, density, and any combination thereof.

Abstract: A method includes operating a downhole acquisition tool in a wellbore in a geological formation. The wellbore or the geological formation, or both, contains a fluid that includes a native reservoir fluid of the geological formation and a contaminant. The method also includes receiving a portion of the fluid into the downhole acquisition tool, obtaining a measured resistivity, a measured conductivity, or both of the portion of the fluid using the downhole acquisition tool, and using a processor of the downhole acquisition tool to obtain a temperature-corrected resistivity, a temperature-corrected conductivity, or both based on a downhole temperature of the portion of the fluid and the measured resistivity, the measured conductivity, or both.

Abstract: Apparatus and methods for performing downhole testing. Example apparatus include a downhole tool string for conveying within a wellbore, the downhole tool string comprising an anchor device, a testing device, and a linear or rotary actuator. The anchor device maintains a portion of the downhole tool string in a predetermined position within the wellbore. The testing device is operable to receive a downhole sample from or test a subterranean formation surrounding the wellbore. The linear actuator is connected between the anchor device and testing device, and moves the testing device relative to the anchor device.

Abstract: A mine bolt includes an elongated body having a first end and a second end positioned opposite the first end, with the elongated body having a first threaded section, a second threaded section, and a non-threaded section positioned between the first threaded section and the second threaded section. The non-threaded section is configured to yield under loading when the mine bolt is installed with grout in a bore hole.

Abstract: A rock anchor assembly includes: a resiliently radially deformable tubular member longitudinally extending between leading and trailing ends and which has an arrestor formation integral with, or engaged to, a trailing end part of the member; an elongate element longitudinally extending through the member between first and second ends and which attaches to the tubular member at spaced distal and proximal load points and which has a failure arrestor fixed at a point within the member; and a faceplate on the tubular member or the elongate member. When the assembly is inserted in a rock hole, with the faceplate bearing against the rock face, and load is applied along the elongate element that will cause the element to sever above the point at which the arrestor is fixed, the failure arrestor engages the arrestor formation, arresting the ejectment of a proximal portion of the elongate element from the hole.

Abstract: The present invention discloses an I-shaped water-retaining dam for an underground reservoir in a coal mine. The I-shaped water-retaining dam is located between coal pillar dams to isolate an underground reservoir from a corresponding coal roadway. The I-shaped water-retaining dam includes an upper flange plate, a web plate, and a lower flange plate from top to bottom, where a vertical face of a dam body is of an I shape; the upper flange plate extends into a roadway roof; two ends of the web plate are embedded into the coal pillar dams; and the lower flange plate extends into a floor. The I-shaped water-retaining dam is located in an underground coal roadway, and bears complex surrounding rock stress. The present invention effectively overcomes water seepage of a weak part at an upper part of a conventional I-shaped water-retaining dam.

Abstract: In an opposed piston engine, an inlet piston crankshaft axis and an exhaust piston crankshaft axis both extend parallel to a central cylinder plane extending through a centerpoint of a cylinder of the engine and along a central axis of the cylinder. The inlet piston crankshaft axis and the exhaust piston crankshaft axis are both offset from the central cylinder plane. The inlet piston and the exhaust piston linked to the inlet piston crankshaft and the exhaust piston crankshaft are arranged so that the inlet piston closes an inlet port as the inlet piston moves from its bottom dead center toward its top dead center at substantially a same time as the exhaust piston closes the exhaust port as the exhaust piston moves from its bottom dead center toward its top dead center.

Abstract: A scroll compressor includes a movable scroll having first key grooves, a stationary member having second key grooves, and an Oldham coupling provided between the movable scroll and stationary member. The Oldham coupling is movable with respect to the stationary member along a first axis, and with respect to the movable scroll along a second axis. The Oldham coupling has an annular body portion, at least two first key portions fitted into the first grooves, and a pair of second key portions fitted into the second grooves. The first horizontal surface has inwardly positioned surfaces positioned more on a center of gravity side of the Oldham coupling than virtual extension lines of first inner peripheral edges that are part of an inner peripheral edge of the annular body portion. The first key portions have inwardly positioned portions that project from the inwardly positioned surfaces.

Abstract: A mixed-flow turbine wheel is proposed which, compared to existing mixed-flow turbine wheels, has reduced mass and moment of inertia because radially-outer portions of existing mixed-flow turbine wheels are omitted. In a first possibility, the omitted material may be scalloping of the back face of the turbine wheel at a radial position outward of a base line which is a circle on the back surface of the wheel which indicates the minimum radius of the back surface. In a second possibility, part of the webbing of each blade is omitted to one side of the blade. Thus, viewing the turbine wheel in the axial direction, the area of the webbing outside the baseline and to one side of a radial line through the inducer tip, may be at least 20% less than that on the other side.

Abstract: Airfoils for gas turbine engines are provided. The airfoils include a body extending between leading and trailing edges in an axial direction, between pressure and suction sides in a circumferential direction, and between a root and tip in a radial direction. A first transitioning leading edge cavity is located adjacent one of the sides proximate the root of the body and transitions axially toward the leading edge as the first transitioning leading edge cavity extends radially toward the tip. A second transitioning leading edge cavity is adjacent the other side and adjacent the leading edge proximate the root of the body and transitions axially toward the trailing edge as the second transitioning leading edge cavity extends radially toward the tip. A portion of the second transitioning leading edge cavity shields a portion of the first transitioning leading edge cavity proximate the root of the body.

Abstract: A component for a turbine engine includes a body having a wall separating a combustion air flow path from a cooling air flow path. The component can include an isolation chamber formed in the cooling air flow path. The component can also include at least one cyclone separator having a cooling air inlet fluidly coupled to the cooling air flow path.

Abstract: Rotor assemblies and methods for manufacturing airfoils for rotor assemblies are provided. For example, a rotor assembly comprises a rotary structure extending circumferentially about an axial centerline of a gas turbine engine and an airfoil having a root and a tip. The root is coupled to the rotary structure and has a bulbous shape. The airfoil is formed from a plurality of composite plies, a portion of which defines at the root first and second end surfaces, which are in contact with the rotary structure and together define a chisel-shaped end of the root. In another embodiment, a rotor assembly comprises an outer rotor extending circumferentially about an axial centerline of a gas turbine engine and a composite outer rotor blade having a root and a tip. The blade root is coupled to the outer rotor and extends inward along a radial direction toward the axial centerline.

Abstract: A multi-stage axial turbine (typically between 4 and 10 stages) designed to operate more efficiently with partial admission of low temperature steam in each stage except the last one or two stages. Each stage of the subject turbine operates efficiently with smaller pressure drops thereby maintaining much smaller reductions in fluid density per stage. Each stage has blisks built as a single piece and the steam passages built into the periphery of the blisks. Each subsequent stage then only requires a small increase in flow area that can be achieved by using only a small increase in admission and blade height.

Abstract: A stator vane including a vane root, a vane tip, a leading edge extending between the root and the tip, the leading edge having a serrated profile having a succession of teeth and of troughs each having an amplitude and a thickness, wherein a series of at least three teeth and three consecutive troughs starting from the vane root and/or from the vane tip have a growing amplitude and/or thickness.

Abstract: Assembly (2) comprising an annular turbine distributor (3) for turbomachinery (1), an annular structural element (4) of the turbomachinery (1), coaxial with the distributor (3) and at least one device (5) for attaching the annular distributor (3) with the annular structural element (4), characterised in that: —the annular distributor (3) is crossed by at least two axial passages, and —the or each attachment device (5) comprises: at least two pins (15), rigidly connected to the annular structural element (4) and passing through one of said passages of the distributor (3), a first transverse stop (16) for stopping the distributor (3) axially and passing through two consecutive pins (15), and two second stops (17) rigidly connected to the structural element (4) to retain, in the pins (15), the first transverse stop (16) for stopping the distributor (3) radially.

Abstract: A diffuser case support structure for a gas turbine engine is disclosed. The diffuser case support structure includes a fairing disposed circumferentially about a longitudinal axis. The fairing forms at least a portion of a fluid path between a compressor and a combustor of the gas turbine engine. The fairing defines a plurality of apertures extending through the fairing. At least one spoke extends through at least one respective aperture of the plurality of apertures. The at least one spoke is configured to couple an inner diffuser case and an outer diffuser case of the gas turbine engine.

Abstract: A seal structure is for sealing leakage fluid flowing through a gap between a rotation member rotating about a rotation axis and a stationary member facing the rotation member. The seal structure includes seal fins projecting from a base that is one of the rotation and stationary members toward the other one, the seal fins being spaced apart from each other at a certain interval in an axial direction of the rotation axis; and a step section provided to the other one, the step section including step surfaces facing the seal fins and a riser surface between the adjacent step surfaces, the step surfaces and the riser surface defining a step portion. The seal fins are inclined upstream in a flow direction of the leakage fluid relative to a radial direction perpendicular to the rotation axis. Each seal fin and the base define a corner portion having a curved surface.

Abstract: A turbine engine component includes: a body bounded by an end face; and a seal slot having an opening communicating with the end face, the seal slot including a receptacle defining a boundary configured to receive and position a spline seal, and an open chamber communicating with the seal slot and extending beyond the boundary.

Abstract: Provided is a stationary nozzle assembly of a gas turbine including a plurality of vane segments converting hot gas energy into a kinetic form, a fixed seal disposed between two adjacent vane segments, and honeycomb seal elements disposed between the two adjacent vane segments to prevent hot gases from escaping through a gap between the two adjacent vane segments. Here, the fixed seal and the honeycomb seal elements face each other. In addition, the vane segments each include airfoil shaped vanes, an outer wall and an inner wall that are disposed at opposite sides of the airfoil shaped vanes, and the fixed seal and the honeycomb seal elements are installed in at least one of the outer wall or the inner wall.

Abstract: A method of manufacturing a hydrostatic advanced low leakage seal configured to be disposed between relatively rotatable components is provided. The method includes manufacturing a plurality of separate, independent components of the seal. The method also includes assembling the plurality of separate, independent components to form the seal.

Abstract: An assembly for a gas turbine engine includes a first casing, a second casing, and struts extending from the first casing to support the second casing. The assembly further includes a fairing and a multi-piece heat shield assembly. The fairing is disposed between the first casing and the second casing and around each of the struts. The multi-piece heat shield assembly includes a first shield extending between the first casing and the fairing, and a second shield extending between the fairing and the first casing. The multi-piece heat shield assembly further includes a third shield extending between the fairing and the second casing, and fourth and fifth heat shields extending from the third heat shield between the fairing and each of the struts.

Abstract: A bolt lock plate includes a plate configured with a multi-point aperture and a slot. The multi-point aperture has an axial centerline and a cross-sectional geometry with a quantity N of points arranged about the axial centerline. The slot extends circumferentially about the axial centerline a quantity M of degrees within the plate and between opposing ends of the slot. The quantity M is at least substantially equal to three-hundred and sixty divided by a product of the quantity N and a constant C. The constant C is equal to one or two.

Abstract: Disclosed is a method for rapidly and flexibly adapting the output of a steam-turbine power station (1), preferably for adapting the output to altered network loads, more preferably for providing a positive and/or negative network operating reserve as required, and especially preferably for providing a primary operating reserve and/or a secondary operating reserve. According to the invention, heat released during the discharge of at least one electrically chargeable thermal store (6) is coupled into a feedwater heater section (3) of the power station (1).

Abstract: A power plant comprises a boiler, a turbine, a condenser, a feed water heater, a deaerator, a deaerator water level control valve, an extraction system which introduces the steam extracted from the turbine into the feed water heater, an extraction valve, an auxiliary steam introduction system which introduces auxiliary steam into the feed water heater, an auxiliary steam control valve and a control device. When a rapid load increase request is made, the control device controls, to orient the extraction valve in a closing direction, to maintain an opening of the deaerator water level control valve, and to orient the auxiliary steam control valve in an opening direction.

Abstract: An adjusting device having at least one tappet assembly. The at least one tappet assembly comprises a tappet, at least one guide cylinder, and a pole core. The tappet is arranged in the guide cylinder in a movable manner along a longitudinal axis, and a non-magnetic connection socket is arranged between the guide cylinder and the pole core. The guide cylinder and the pole core are arranged at a distance to each other in the longitudinal axis by the connection socket.

Abstract: Improved multi-section slide valves for internal combustion engines for improved aspiration comprise spaced apart, continuously pressurized, annular oil confinement zones that are defined between select groups of arrays of piston rings. The oil confinement zones are axially spaced along the length of the slide valve and continuously pressured by oil flow passageways communicating between spaced apart arrays of piston rings. During slide valve movement these pressurized oil confinement zones tend to stabilize the slide valve, preventing metal-to-metal contact such as that associated with rocking, tipping, chafing or scrubbing.

Abstract: A method of providing a rocker arm set for a valvetrain includes providing a first rocker arm configured as a switching rocker arm for a first intake valve, and providing a second rocker arm configured as a fixed rocker arm for a second intake valve, the second rocker arm operating in a normal Otto cycle mode. The first rocker arm operates in a late intake valve closing (LIVC) mode where the first rocker arm is configured to close the first intake valve later than the second intake valve.