Valve Timing Control Spool Throttle Region Locking

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional valve timing control apparatuses face challenges in maintaining accurate valve timing control, particularly at fail times when the driving force is not applied, leading to increased working fluid flow and difficulty in locking the vane rotor into a predetermined phase, which can result in engine failures such as knocking, stall, or activation errors.

Innovation Solution

A valve timing control apparatus with a spool that moves between a variable region and a lock region, where the throttle region is set at the spool's end position in the second direction without a driving force, reducing the working fluid flow to the advance chamber and ensuring the rotation phase can be easily locked into a predetermined phase, even at fail times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the throttle region is located to be depart from the end position of the spool in the first direction, then the working fluid flow can be reduced during normal operation, but at fail time the spool reaches the end position in the second direction causing increased working fluid flow and difficulty in locking the vane rotor

Engineering Contradiction:

Improvelocking reliabilityVSAvoidfail-safe operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The invention converts the harmful effect of increased working fluid flow at fail time into a beneficial throttling effect. By positioning the throttle region at the end position in the second direction, the spool automatically enters the throttle region when driving force is lost, converting the fail condition into a safe locked state through reduced fluid flow to the advance chamber.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The throttle region is preliminarily positioned at the end position in the second direction to prevent the harmful effect of excessive working fluid flow. This preliminary arrangement ensures that when the spool moves to the end position due to loss of driving force, the throttling effect is already in place to reduce fluid flow and enable reliable locking.

Inventive Principle:

Principle #9Preliminary anti-action

2Productivity

If the spool is moved to the end position in the second direction at fail time, then the spool reaches a position that increases working fluid flow to the advance chamber, but this makes it difficult to lock the vane rotor into the predetermined phase

Engineering Contradiction:

Improveresponse speedVSAvoidphase locking accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The invention converts the potentially harmful increase in working fluid flow at fail time into a beneficial throttling effect by positioning the throttle region at the end position. This ensures that even when the spool reaches the end position, the fluid flow is reduced through throttling, enabling reliable phase locking rather than causing locking failure.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If the throttle region is set at the movable end position of the spool in the second direction, then fail-safe locking is achieved, but the throttle region must be precisely positioned during manufacturing

Engineering Contradiction:

Improvefail-safe propertyVSAvoidthrottle region positioning

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The spool valve structure provides self-service by automatically positioning itself into the throttle region when reaching the end position in the second direction. This self-positioning mechanism reduces the need for high-precision manual adjustment during manufacturing, as the fail-safe function is achieved through the inherent mechanical limits of the spool travel.

Inventive Principle:

Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The apparatus achieves high-speed responsivity and fail-safe properties by throttling the working fluid flow, ensuring the rotation phase is securely locked, preventing engine failures and maintaining efficient valve timing control.

Implementation Method 1

The spool is moved based on a balance between a driving force of an electromagnetic solenoid and a biasing force of a spring

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

the biasing force is applied in a second direction opposite from the first direction, in the axis direction

Methodology Applied

Scientific EffectElastic force: Elasticity

Implementation Method 3

The working fluid discharged from or introduced into the lock chamber is controlled at the same timing as the working fluid discharged from or introduced into the advance/retard chamber by a control valve

Methodology Applied

Scientific EffectFluid pressure: Pressure Gradient

Data Source

PatentUS9121312B2Valve timing control apparatus

Publication Date: 2015.09.01 DENSO CORP

AI summary

A driving portion is configured to cause a driving force to move a spool in a first direction, and a bias unit is configured to cause a biasing force to bias the spool in a second direction in an axis direction. A part of a lock region is defined as a throttle region at which a flowing amount of working fluid flowing from a supply port to an introduction port is throttled. The throttle region is set to be located at a movable end position of the spool in the second direction to which the spool arrives when the driving force is not applied to the spool.