Valve Timing Control Apparatus Air Foam Discharge

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Solution Overview

Problem

Existing valve timing control apparatuses face challenges in accurately controlling valve timing due to air foam formation during engine speed transitions, leading to abnormal vane rotor movements and rapid engine state changes, especially when the engine shifts from low to high rotation states.

Innovation Solution

A valve timing control apparatus with a phase controller that alternately changes or locks the rotation phase of the vane rotor between advance and retard positions using working fluid pressure control, ensuring air foam is discharged and preventing abnormal movements by synchronizing with engine speed and temperature conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the rotation phase is compulsorily changed when engine rotation speed exceeds a predetermined speed, then air foam can be discharged from the chamber, but the control is performed in vain when air foam is not present and causes rapid engine state changes

Engineering Contradiction:

Improveaccuracy of valve timing controlVSAvoidcomplexity of control logic

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The control device monitors engine rotation speed continuously and uses this feedback to determine when to activate compulsory rotation phase change. By basing the control decision on actual engine state feedback rather than fixed thresholds, the system avoids unnecessary activation when air foam is not present, improving control accuracy while maintaining relatively simple implementation.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The control device activates the compulsory rotation phase change in advance when specific conditions are detected (engine rotation speed exceeding predetermined speed while intake valve timing is in a specific range), preventing air foam formation before it can cause problems. This preliminary action ensures air foam is discharged proactively rather than reactively, improving reliability without requiring complex real-time detection systems.

Inventive Principle:

Principle #10Preliminary action

2Speed

If working fluid pressure is increased to synchronize with high engine rotation speed, then air foam introduction is prevented, but air foam mixing occurs when engine rotation speed is low

Engineering Contradiction:

Improveengine rotation speed synchronizationVSAvoidconsistency of working fluid introduction

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The control system dynamically adjusts the timing of compulsory rotation phase change based on real-time engine rotation speed and intake valve timing conditions. By making the control timing variable rather than fixed, the system optimizes working fluid introduction synchronization across different engine speeds, preventing air foam at high speeds while avoiding unnecessary intervention at low speeds where air foam naturally dissipates.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control device changes the timing parameter of compulsory rotation phase change based on engine rotation speed and intake valve timing position. By adjusting this parameter dynamically, the system ensures optimal working fluid pressure synchronization with engine speed variations, maintaining consistent and reliable working fluid introduction across the entire operating range without air foam contamination.

Inventive Principle:

Principle #35Parameter changes

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

This solution allows for pinpoint control of valve timing, restricting rapid engine state changes and ensuring accurate operation by effectively managing air foam and fluid pressure, thereby preventing abnormal vane rotor movements.

Implementation Method 1

working fluid is controlled to flow into or out of operation chambers

Methodology Applied

Scientific EffectFluid pressure: Pressure Increase

Implementation Method 2

The vane rotor has a rotation phase with respect to the housing, and the rotation phase is changed by working fluid flowing into or out of the operation chambers

Methodology Applied

Scientific EffectHydraulic actuation: Hydraulic Press

Data Source

PatentUS8855893B2Valve timing control apparatus

Publication Date: 2014.10.07 NIPPON SOKEN

AI summary

A valve timing control apparatus includes a housing that is rotatable with a crankshaft; a vane rotor that is rotatable with a camshaft; and a phase controller to compulsorily change a rotation phase of the vane rotor alternately between an advance side and a retard side with respect to the housing if an engine shifts to a high rotation state after the engine continuously has a low rotation state for a predetermined period or more. The engine in the low rotation state has a rotation speed lower than a predetermined rotation speed. The engine in the high rotation state has a rotation speed equal to or higher than the predetermined rotation speed.