Valve Timing Control Mechanical Locking Mechanism

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Solution Overview

Problem

Existing valve timing control systems for internal combustion engines require a separate hydraulic pressure source to hold the valve timing at a retarded phase during automatic engine stop in idling-stop systems, which complicates the system and increases costs.

Innovation Solution

A valve timing control apparatus that uses a locking mechanism with multiple lock pins and guide grooves to mechanically hold the vane rotor at specified phases, eliminating the need for hydraulic pressure to maintain the maximum phase-retard position, and allows for hydraulic pressure control of phase-change chambers independently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydraulic pressure is used to hold the vane rotor at the maximum phase-retard position during automatic engine stop, then the valve timing can be maintained at the retarded phase, but a separate hydraulic pressure source is required which complicates the system and increases costs

Engineering Contradiction:

Improvevalve timing maintenanceVSAvoidhydraulic pressure source

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the hydraulic pressure-based holding mechanism with a pure mechanical locking mechanism. The locking member with locking protrusions engages with locking recesses in the housing to mechanically hold the vane rotor at the maximum phase-retard position, eliminating the need for a separate hydraulic pressure source while maintaining reliable valve timing during automatic engine stop.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and removes the separate hydraulic pressure source from the system. By implementing a mechanical locking mechanism that operates independently of hydraulic pressure, the system eliminates the complex hydraulic infrastructure required for holding valve timing during automatic engine stop, thereby simplifying the overall device architecture.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If hydraulic pressure is used to hold the vane rotor at the intermediate phase, then the valve timing can be maintained at the intermediate phase, but the system requires separate hydraulic control mechanisms for different phases

Engineering Contradiction:

Improvevalve timing controlVSAvoidhydraulic control mechanism

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the valve timing control into distinct mechanical locking positions. The locking member can engage with different locking recesses corresponding to the maximum phase-retard position and the intermediate phase position, providing discrete, reliable holding points without requiring continuous hydraulic pressure control for each phase.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a universal mechanical locking mechanism that can hold the vane rotor at multiple positions (maximum phase-retard position and intermediate phase position) using the same locking member and locking recess structure. This multi-functional locking mechanism eliminates the need for separate hydraulic control mechanisms for different phases.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 simplifies the system, reduces costs by eliminating the need for a separate hydraulic pressure source, and enhances the responsiveness and accuracy of valve timing control by allowing mechanical locking at the maximum phase-retard position, improving engine startability and reducing noise and vibrations.

Implementation Method 1

configured to rotate the driven rotary member relative to the driving rotary member in a phase-advance direction by supplying hydraulic pressure to each of the phase-advance hydraulic chambers and exhausting working fluid from each of the phase-retard hydraulic chambers

Methodology Applied

Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentUS8925506B2Valve timing control apparatus of internal combustion engine

Publication Date: 2015.01.06 ASTEMO LTD

AI summary

In a valve timing control apparatus configured to enable rotary motion of a vane rotor relative to a sprocket in a phase-retard direction or in a phase-advance direction by controlling hydraulic-pressure supply-and-exhaust for each of phase-advance hydraulic chambers and hydraulic-pressure supply-and-exhaust for each of phase-retard hydraulic chambers, first and second lock pins are located in a large-diameter rotor portion rather than a small-diameter rotor portion. The rotary motion of the vane rotor relative to the sprocket from an intermediate lock position between a maximum phase-advance position and a maximum phase-retard position is restricted by engagement of the first lock pin with a first lock hole and by engagement of the second lock pin with a second lock hole. The vane rotor is held at the maximum phase-retard position by engagement of the first lock pin with the second lock hole.