A hydraulic fluid control valve (HFCV) configured to recirculate an exiting hydraulic fluid from a first hydraulic actuation chamber to a second hydraulic actuation chamber is provided. The HFCV includes a spring well that combines a hydraulic fluid received from a hydraulic fluid pressure source with a recirculated hydraulic fluid from the first hydraulic actuation chamber and delivers the combination to the second hydraulic actuation chamber.

A hydraulically-actuated variable camshaft timing (VCT) system comprises a spool valve including a sleeve and a spool, having a plurality of radially-outwardly extending lands, received within a sleeve; a sleeve fluid pathway, extending axially along the sleeve and formed within the sleeve, configured to receive fluid from a fluid supply; an advancing port in the sleeve in fluid communication with an advancing chamber of a hydraulically-actuated camshaft phaser; a retarding port in the sleeve in fluid communication with a retarding chamber of the hydraulically-actuated camshaft phaser; a first fluid supply port formed in the sleeve; a second fluid supply port formed in the sleeve; and an exhaust port axially positioned in the sleeve in between the first fluid supply port and the second fluid supply port or in between the advancing port and the retarding port, wherein the exhaust port is configured to selectively receive fluid from either the advancing chamber or the retarding chamber depending on an axial position of the spool relative to the sleeve.

This disclosure relates to a control valve for a hydraulic camshaft phaser. The control valve includes a screw body having a cavity, a plurality of connections opening into the cavity, and a sleeve-shaped hydraulic guide element firmly inserted radially inside the cavity. At least part of the hydraulic guide element consists of plastic. The hydraulic guide element includes a plurality of pressure medium channels which open into its radial interior, each of which is connected to at least one of the connections. A control piston is displaceably accommodated in the hydraulic guide element, and, depending on the position of the control piston, connects the connections to each other. A sealing contour provided on a radial outer side of the hydraulic guide element contacts the screw body, sealing the pressure medium channels with respect to each other and/or with respect to axial ends of the hydraulic guide element.

Methods and systems are provided for providing secondary air to an exhaust system during catalyst warm-up. In one example, a method may include, during a cold start condition, operating an engine with a first number of cylinders unfired and a remaining number of cylinders fired during an engine cycle, opening an intake valve of an unfired cylinder of the first number of cylinders during an expansion stroke of the unfired cylinder, and opening an exhaust valve of the unfired cylinder during a compression stroke of the unfired cylinder. In this way, the unfired cylinders may provide the secondary air to the exhaust system during a stroke that increases mixing of the secondary air with burned exhaust gas from fired cylinders, thus increasing exotherm production in the exhaust system to increase a temperature of the catalyst.

A valve timing adjustment device includes: a center bolt being bottomed cylindrical; a spool disposed in a hollow portion of the center bolt so as to be linearly movable; an oil supply path including a region that is formed inside a cylindrical wall of the center bolt and along the longitudinal direction of the center bolt; a first annular groove formed on the inner periphery of the center bolt and communicating with the oil supply path; and a second annular groove formed on the outer periphery of the spool, disposed to face the first annular groove, and communicating with the oil supply path via the first annular groove. The oil supply path is capable of selectively, communicating with either a first work port or a second work port via the first annular groove and the second annular groove depending on the position of the spool that is linearly moving.

Methods and systems are provided for providing secondary air to an exhaust system during catalyst warm-up. In one example, a method may include, during a cold start condition, operating an engine with a first number of cylinders unfired and a remaining number of cylinders fired during an engine cycle, opening an intake valve of an unfired cylinder of the first number of cylinders during an expansion stroke of the unfired cylinder, and opening an exhaust valve of the unfired cylinder during a compression stroke of the unfired cylinder. In this way, the unfired cylinders may provide the secondary air to the exhaust system during a stroke that increases mixing of the secondary air with burned exhaust gas from fired cylinders, thus increasing exotherm production in the exhaust system to increase a temperature of the catalyst.

A clip filter for a hydraulic valve, the clip filter comprising a carrier frame; and filter elements received in the carrier frame, wherein the carrier frame is configured annular and includes a clip filter lock, wherein a first end of the carrier frame and a second end of the carrier frame are engageable with each other for closing the clip filter, wherein the first end of the carrier frame includes a lug shaped clip element and the second end of the carrier frame includes a recess that is complementary to the lug shaped clip element, and wherein a clip filter lock is configured for a maximized opening force.

A sprocket assembly which is either driven by a drive chain or which drives the drive chain includes a hub centered about a sprocket axis and defining a hub radially outer surface; a plurality of sprocket teeth extending radially outward from the hub; and a cushion ring assembly adjacent to the plurality of sprocket teeth and circumferentially surrounding the hub radially outer surface. The cushion ring assembly includes a cushion ring adjacent to the plurality of sprocket teeth and circumferentially surrounding the hub radially outer surface; the cushion ring being resilient and compliant. The cushion ring assembly also each includes a retention ring which is partially embedded within the cushion ring and which engages the hub radially outer surface in an interference fit, the retention ring providing axial and radial retention of the cushion ring to the hub.

A control valve includes a valve housing extending along a longitudinal axis. The valve housing defines an inlet port, a first outlet port, and a second outlet port. In addition, the control valve includes a spool guide disposed inside the valve housing and a flow guide belt disposed around the spool guide. The flow guide belt is disposed inside the valve housing. The control valve further includes a spool movably disposed in the spool guide. The spool can move relative to the valve housing along the longitudinal axis between a first spool position and a second spool position. The first outlet port is in fluid communication with the inlet port when spool is disposed in the first spool position.

A diagnostic system for a vehicle includes a difference module, a Fourier module, and a fault module. The difference module determines pressure differences for a camshaft revolution based on differences between: first pressures within first chambers of a camshaft phaser measured during the camshaft revolution, wherein the first pressures within the first chamber control advancement of the camshaft relative to a crankshaft of an engine; and second pressures within second chambers of the camshaft phaser measured during the camshaft revolution, wherein the second pressures within the second chamber control retardation of the camshaft relative to the crankshaft of the engine. The Fourier module performs a Fourier Transform (FT) based on the pressure differences to produce FT data. The fault module, based on the FT data, selectively indicates that a fault is present in a variable valve lift mechanism that is actuated by the camshaft.