Valve Timing Adjusting Device with Temperature Sensing Lock

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Solution Overview

Problem

Hydraulic valve timing adjusting devices for internal combustion engines face issues such as knocking, pre-ignition, and uncomfortable vibrations due to high compression ratios during warm starting, and difficulty in maintaining optimal valve timing during cold starting, leading to startability problems.

Innovation Solution

A valve timing adjusting device with a temperature sensing body that expands or contracts to lock or release the main lock member at specific phases, allowing the rotation phase to be adjusted based on engine temperature, ensuring suitable starting conditions by locking the phase at the main lock phase during warm starts and shifting to an earlier subordinate lock phase during cold starts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the intake valve is closed at an early timing (intermediate phase) to increase compression ratio and improve cold starting, then cold startability is improved, but knocking and pre-ignition occur during warm starting

Engineering Contradiction:

Improvecold startabilityVSAvoidknocking and pre-ignition

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The valve timing is made dynamically adjustable based on engine temperature conditions. The system automatically selects between intermediate phase (for cold starting) and retard phase (for warm starting) using a temperature sensing body that detects engine temperature and actuates a locking mechanism to lock the selected phase, enabling dynamic adaptation to varying operating conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the valve timing parameter (rotation phase) based on engine temperature. By sensing temperature and locking either the intermediate phase or retard phase, the system optimizes valve timing parameters for different temperature conditions, preventing knocking during warm starting while maintaining improved cold starting capability

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the rotation phase is adjusted by applying working liquid pressure to the vane rotor during warm starting, then the retard phase can be selected, but the rotation phase is easily shifted from the retard phase due to varying torque

Engineering Contradiction:

Improverotation phase selectionVSAvoidrotation phase stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The hydraulic pressure-based phase selection is supplemented with a mechanical locking system. The locking mechanism physically secures the selected rotation phase (intermediate or retard) in place, replacing reliance solely on hydraulic pressure to maintain phase stability, thereby preventing unintended phase shifts due to varying torque

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The locking mechanism acts as an intermediary between the hydraulic pressure system and the rotation phase. It receives the selected phase position and locks it mechanically, ensuring stable maintenance of that phase regardless of hydraulic pressure fluctuations or torque variations

Inventive Principle:

Principle #24Intermediary (Mediator)

3Speed

If the working liquid pressure is decreased during starting, then the vane rotor rotates to an advance side, but the lock body moves to lock releasing position and the rotation phase cannot be locked

Engineering Contradiction:

Improvevane rotor rotationVSAvoidlocking function

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The locking mechanism is designed to engage the lock body with the lock groove at the target rotation phase position before the working liquid pressure decreases and causes the lock body to move to the releasing position. This preliminary locking action ensures the rotation phase is secured while allowing the necessary rotor rotation to occur

Inventive Principle:

Principle #10Preliminary action

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 effectively inhibits malfunctions like knocking and pre-ignition during warm starts while improving ignitability and startability during cold starts by optimizing the valve timing based on engine temperature, ensuring reliable engine operation across varying conditions.

Implementation Method 1

a lock control portion (18) having a temperature sensing body (185) to be expanded and contracted

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS8991345B2Valve timing adjusting device

Publication Date: 2015.03.31 DENSO CORP

AI summary

A main lock member is fitted in a main lock bore at a main lock phase for closing an intake valve at a timing later than a timing when a piston reaches a bottom dead center, whereby a rotation phase is locked. In a subordinate lock mechanism, the rotation phase is locked at a subordinate lock phase advancing further than the main lock phase. In a lock control mechanism, a temperature sensing body is changed to an expanded state, whereby a moving member is latched at a first position in which the main lock member is allowed to be fitted in the main lock bore, whereas at a main lock phase in a cold stop state after a timing when the temperature of the stopped internal combustion engine becomes less than a preset temperature, the temperature sensing body is changed to a contracted state.