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Variable cam timing system and method for operation of said system

A timing system, cam technology, applied in the direction of camshaft drive, valve drive, machine/engine, etc., can solve the problem of not being able to perform valve timing and valve deactivation at the same time, reducing engine efficiency, and inoperable phasers.

Pending Publication Date: 2019-06-28
FORD GLOBAL TECH LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, if a cam phaser is used in conjunction with a valve deactivation device, the phaser may become inoperable due to the reduction i

Method used

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  • Variable cam timing system and method for operation of said system
  • Variable cam timing system and method for operation of said system
  • Variable cam timing system and method for operation of said system

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Embodiment Construction

[0014] A variable cam timing system is described herein that generates supplemental camshaft torque to enable torque-actuated cam phasers to operate over a wider range of conditions. Operating the cam phaser over an extended range of conditions enables increased engine efficiency while reducing emissions. In one example, a variable cam timing system includes a zero cam rotationally coupled to a camshaft that cyclically actuates a zero follower independent of valve actuation. Thus, zero cams and zero followers are not associated with engine valve actuation and are isolated from cylinder valves in the engine. The interaction between the zero cam and the zero follower generates camshaft torque, which may be utilized by torque-actuated cam phasers to adjust (eg, advance or retard) valve timing. In one example, a variable cam timing system may include a zero cam deactivation device designed to activate and deactivate a zero follower to vary the amount of torque applied to the cams...

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Abstract

The invention provides a variable cam timing system and a method for operation of said system. The variable cam timing system in an engine is provided. The variable cam timing system includes a camshaft receiving rotational input from a crankshaft. The camshaft includes a valve cam rotationally actuating a valve coupled to a cylinder and a null cam actuating a null follower including a null springexerting a return force on the null cam during interaction between the null cam and the null follower, where the null follower is independent from the cylinder.

Description

technical field [0001] The present description generally relates to variable cam timing systems and methods for operating variable cam timing systems. Background technique [0002] Camshaft torque-actuated (CTA) variable cam timing (VCT) devices rely on camshaft torque induced by cylinder valve lift events to adjust the engine's camshaft timing. When torque-actuated cam phasers are used in conjunction with valve deactivation systems, such valve lift may not occur, and the resulting reduction in camshaft torque or (in some cases) the absence of camshaft torque may prevent cam Reliable actuation of shaft phasers. As a result, desired camshaft timing adjustments may not be achieved during valve deactivation. [0003] US 7,255,077 discloses a cam phaser which adjusts the cam timing of the valves. However, if a cam phaser is used in conjunction with a valve deactivation device, the phaser may become inoperable due to the reduction in cam torque. Accordingly, valve timing and ...

Claims

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Application Information

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IPC IPC(8): F01L1/344F01L1/06F01L13/00
CPCF01L1/08F01L1/185F01L1/2405F01L1/3442F01L13/0005F01L2001/186F01L2013/001F01L2250/02F01L2250/04F01L2800/00F01L1/34409F01L2201/00F01L2001/34453F01L2001/3443F01L1/022F01L1/024F01L2001/34483
Inventor 约翰·罗林杰杰米·汉肖亚当·克拉奇
Owner FORD GLOBAL TECH LLC