Variable Valve Control Shaft Torque Alignment

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Solution Overview

Problem

Existing variable valve apparatuses for internal combustion engines require large actuators to quickly change valve lift from high to low, leading to increased size, weight, and energy consumption, as well as reduced engine mountability and responsiveness.

Innovation Solution

The control shaft is designed to easily rotate from high to low valve lift by aligning the direction of maximum load generated at the oscillating fulcrum with the rotating direction of the control shaft, utilizing the rotary torque around the control shaft's center to reduce the control load required, allowing quick response with a small-capacity actuator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a large-capacity actuator is used to quickly change valve lift from high to low, then variable response speed is improved, but actuator size, weight, and energy consumption increase

Engineering Contradiction:

Improvevariable response speedVSAvoidactuator weight

Core Design Contradiction:

SpeedVSWeight of moving object

Solution Approach 1:

The patent inverts the conventional approach by designing the control shaft and transmission arm geometry such that the maximum load during valve opening generates rotary torque in the same direction as the required rotation for reducing valve lift. This converts a potentially harmful load into a beneficial driving force, enabling quick response without a large actuator

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent converts the maximum load (which would normally oppose the rotation needed to reduce valve lift) into a beneficial rotary torque that facilitates the desired rotation. By aligning the load direction with the required rotation direction through proper geometric design, the system uses the engine's own operating forces to assist the actuator's work

Inventive Principle:

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

2Speed

If a large-capacity actuator is used to quickly change valve lift from high to low, then variable response speed is improved, but device size is increased

Engineering Contradiction:

Improvevariable response speedVSAvoidactuator volume

Core Design Contradiction:

SpeedVSVolume of moving object

Solution Approach 1:

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent employs dynamic geometric design where the transmission arm and control shaft are configured to optimize the direction of forces during operation. The geometry allows the system to dynamically convert loads into useful torque during the critical phase of valve lift reduction

Inventive Principle:

Principle #15Dynamics

3Speed

If a large-capacity actuator is used to quickly change valve lift from high to low, then variable response speed is improved, but energy consumption is increased

Engineering Contradiction:

Improvevariable response speedVSAvoidactuator energy consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

Inventive Principle:

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

Solution Approach 2:

The system uses its own operational loads to assist in the control process. The maximum load generated during normal valve opening operations is harnessed to provide the rotary torque needed for quick valve lift reduction, making the system partially self-servicing and reducing external energy requirements

Inventive Principle:

Principle #25Self-service

4Speed

If a large-capacity actuator is used to quickly change valve lift from high to low, then variable response speed is improved, but engine mountability is degraded

Engineering Contradiction:

Improvevariable response speedVSAvoidengine mountability

Core Design Contradiction:

SpeedVSAdaptability or versatility

Solution Approach 1:

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS7284515B2Variable valve apparatus of internal combustion engine

Publication Date: 2007.10.23 MITSUBISHI MOTORS CORP

AI summary

In a variable valve apparatus according to the present invention, a direction of a maximum load generated during valve lift at an oscillating fulcrum of a transmission arm with respect to a control shaft and a rotating direction when the control shaft is varied from the valve lift side to the low-valve lift side are set in the same direction. Consequently, the control shaft is made to easily oscillate in the direction from the high valve lift side to the low valve lift side.