1163 results about "Valve timing" patented technology

A method of operating an engine having a hotter and colder airstreams separately controlled to a cylinder is provided. The method controls valve timing during a transition in operating modes to provide improved operation.

Various systems and methods are disclosed for carrying out combustion in a fuel-cut operation in some or all of the engine cylinders of a vehicle. Further, various subsystems are considered, such as fuel vapor purging, air-fuel ratio control, engine torque control, catalyst design, and exhaust system design.

A four-cycle engine is provided with valve timing adjusters for adjusting opening and closing timing an and an exhaust valve. In medium- to high-speed ranges in medium- to high-load regions of the engine, a closing point (ExC) of the exhaust valve defined as a point of transfer from an acceleration portion to a constant speed portion on its valve lift characteristics curve is set to a point a specific period before an intake top dead center, and an opening point (InO) of the intake valve defined as a point of transfer from a constant speed portion to an acceleration portion on its valve lift characteristics curve is set to a point after the intake top dead center. In addition, the period from the closing point (ExC) of the exhaust valve to the opening point (InO) of the intake valve is made longer in the medium-speed range than in the high-speed range in the medium- to high-load regions of the engine.

A valve timing control device includes a purge path communicating between a hydraulic chamber allowing the entry of hydraulic pressure on starting an engine and a backward pressurized section in an accommodation hole. When the hydraulic chamber allowing the entry of hydraulic pressure on starting the engine is the retardation side hydraulic chamber, a hydraulic pressure derived from an oil pump is supplied to the retardation side hydraulic chamber on starting the engine. On the way, air-mixed oil is discharged to outside of the device by way of a purge path, a backward pressurized section in the accommodation hole and the discharge hole. When the air is discharged, a residual pressure is produced in the backward pressurized section due to oil supplied thereto. The residual pressure results in the increase of an unlocking hydraulic pressure to prevent a locking member from being unlocked. When the application of a retardation side hydraulic pressure is switched to that of an advance side hydraulic pressure, the pressure presses a front end of a locking member against only a biasing force of a biasing means to unlock a locking relation. The valve timing control device allows the use of any kinds of locking pins, and prevents the occurrence of beat noise (abnormal noise) when air-mixed oil unlocks a locking relation on starting the engine.

Various systems and methods are disclosed for carrying out combustion in a fuel-cut operation in some or all of the engine cylinders of a vehicle. Further, various subsystems are considered, such as fuel vapor purging, air-fuel ratio control, engine torque control, catalyst design, and exhaust system design.

A GMR sensor element is proposed, having a rotationally symmetrical positioning of especially eight GMR resistor elements which are connected to each other to form two Wheatstone's full bridges. This GMR sensor element is especially suitable for use in an angle sensor for the detection of the absolute position of the camshaft or the crankshaft in a motor vehicle, particularly in the case of a camshaft-free engine having electrical or electrohydraulic valve timing, of a motor position of an electrically commutated motor, or of detection of a windshield wiper position, or in the steering angle sensor system in motor vehicles.

A method is provided for control of transition between combustion modes of a direct-injection engine operable in a homogeneous charge compression ignition (HCCI) mode at lower loads and a spark ignition flame propagation (SI) mode at higher loads. The engine includes a variable valve actuation system including two-step high and low lift valve actuation and separate cam phasing for both intake and exhaust valves. The method includes operating the engine at steady state, with fuel-air-exhaust gas mixtures at predetermined conditions, for each speed and load, and controlling the engine during mode changes between the HCCI mode and the SI mode by switching the exhaust and intake valves between low lift for HCCI operation and high lift for SI operation. High load may be an SI throttled mode with an intermediate unthrottled mode (SI / NTLC} in which transition between HCCI and SI / NTLC modes requires switching only the exhaust valve lift and transition between SI / NTLC and SI throttled modes requires switching only the intake valve lift, with predetermined phase adjustments in the valve timing phasing.

A valve timing adjusting apparatus for an internal combustion engine having a bearing includes a camshaft, a housing, a vane rotor, a control valve, and a fastening member. The fastening member is mounted on an axial end portion of the camshaft on a side of the vane rotor opposite from the bearing. The vane rotor is coaxially fastened to the camshaft between the fastening member and a step portion, which is provided to the camshaft on a side of the bearing. A sleeve of the control valve is coaxially received in an axial hole of the camshaft, which opens at an end surface of the end portion of the camshaft. Each of the advance output port and the retard output port is communicated with a corresponding one of the advance chamber and the retard chamber through the camshaft.

Method and system embody a valve timing strategy to control the autoignition timing of a four stroke internal combustion engine (10) operated in an HCCI mode at different engine operating conditions such as different engine speed and torque. A particular valve timing strategy varies lift timing of the intake valve (20) relative to the exhaust valve (28), or vice versa, and relative to top dead center in response to a change in engine torque, for example, to vary amount of trapped residual burned gas in the combustion chamber (12) flowing to an intake or exhaust port (16,18) and back to the combustion chamber during which the residual gas is cooled. Control of the flow of residual gas between the combustion chamber and intake or exhaust port and thus its temperature by the valve timing strategy, in turn, is used to control the temperature of the fresh air / residual gas / fuel mixture in the combustion chamber (12) and thus autoignition timing in response to a change in engine torque.

A relative rotation angle control mechanism of a valve timing control device comprises a radial guide provided by one of drive and driven rotation members which are rotatable about a given axis. A movable control member is guided by the radial guide in a manner to move in a radial direction with respect to the given axis. A link links the movable control member to a given portion of the other of the drive and driven members. The given portion is positioned away from the given axis in a radial direction. An intermediate rotation member is rotatable about the given axis relative to both the drive and driven rotation members. A spiral guide is provided by the intermediate rotation member to guide the movement of the movable control member, so that rotation of the intermediate rotation member relative to the radial guide induces a radial movement of the movable control member. A sliding resistance reducing structure is further arranged between the movable control member and the intermediate rotation member to reduce a sliding resistance produced when the movable control member is moved.

A method for controlling engine torque during disruption of a primary communication link between an engine control unit and a valve control unit in an engine is provided. The method includes determining disruption of the primary communication link between the engine control unit and the valve control unit, operating a preset valve timing schedule upon determination of disruption of the communication link between the engine control unit and the valve control unit; and sending a status message from the valve control unit to the engine control unit regarding the operational status of the valve control unit.

A valve timing adjusting apparatus that selectively controls a restraint mechanism for restraining relative rotation between a housing member and a vane member to increase the operational life thereof. When a vane rotor is held at a most lagging angular position, an end holding mode is executed to pull out a stopper piston from a stopper hole by fluid pressures of both a leading angle side and a lagging angle side. As a result, when the vane rotor rotates from the most lagging angular position to the leading angle side, torsional forces on the stopper piston and the stopper hole can be minimized as the vane member direction of rotation changes. Since a fluid pressure has already been applied to each of leading angle fluid pressure chambers in the end holding mode, the vane rotor can be rotated from the most lagging angular position to the leading angle side quickly by increasing fluid pressure applied to each of the leading angle fluid pressure chambers without the need to switch a fluid path. In addition, since the fluid pressure applied to each of the leading angle fluid pressure chambers in the end holding mode is smaller than fluid pressure for rotating the vane rotor to the leading angle side, generation of impact sound due to collisions of vanes can be avoided.

A valve spring device using pressurized gas for use in biasing a reciprocating valve which moves between a seated position and open position. The device features a static housing having a static chamber what is translateably engaged with dynamic housing. Chambers inside both housings are sealably engaged such that the dynamic housing translates away from the static housing when pressurized gas is communicated to the engaged sealed chambers thereby biasing the dynamic housing away from the static housing and moving the attached valve. Timing of oscillation of the translation and resulting valve timing is controlled by a controller activating a control valve between a pressurizing state and a venting state. The timing may be adjusted to accommodate the engine timing through varying the controller's activation of the control valve and optionally varying the pressure of the gas using a regulator.