Shutoff Valve Initialization Reducing Mechanical Stress
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Solution Overview
Problem
The existing evaporated fuel treatment devices suffer from durability deterioration of the shutoff valve due to repeated mechanical loading during initialization processing, as the drive force operates in the closing direction without knowing the valve's initial position, leading to excessive mechanical stress.
Innovation Solution
The evaporated fuel treatment device employs a control device that performs two distinct initialization processes: a first process operating the shutoff valve to its operation limit when the current position is unknown, and a second process moving it from the current position to the initial position with a smaller operating amount when the specific event has not occurred, thereby reducing mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the shutoff valve is operated to its operation limit during initialization processing to ensure it reaches the mechanical operation limit, then the initial position can be reliably found, but mechanical loading is repeatedly applied to the shutoff valve causing durability deterioration
Solution Approach 1:
The initialization processing is divided into two distinct processes: a first process that operates the shutoff valve to its operation limit when the current position is unknown, and a second process that operates the shutoff valve by a smaller amount from the current position to the initial position when the current position is known. This segmentation allows the system to apply the more aggressive first process only when absolutely necessary, thereby reducing repeated mechanical loading and improving shutoff valve durability while still ensuring accurate initial position detection when needed.
2Stability of the object's composition
If initialization processing is performed by operating the shutoff valve to its operation limit irrespective of current position, then the initial position can be reliably established, but the drive force operates in the closing direction even after reaching the operation limit causing excessive mechanical stress
Solution Approach 1:
The initialization processing is segmented into two processes: a first process that operates the shutoff valve to its operation limit when the current position is unknown, and a second process that operates the shutoff valve by a smaller amount from the current position to the initial position when the current position is known. This segmentation ensures that the aggressive first process is applied only when absolutely necessary, thereby reducing repeated mechanical loading and improving shutoff valve durability while still ensuring accurate initial position detection when needed.
Solution Approach 2:
The control device detects whether a specific event has occurred that makes the current position unknown, and based on this feedback, selectively executes either the first process or the second process. This feedback mechanism prevents unnecessary execution of the aggressive first process, thereby reducing mechanical stress on the shutoff valve while maintaining initial position stability when needed.
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 approach reduces the frequency of drive force application in the closing direction, thereby minimizing durability deterioration of the shutoff valve during initialization processing.
Implementation Method 1
a canister (13) that adsorbs evaporated fuel generated within a fuel tank (3)
Data Source
AI summary
The evaporated fuel treatment device includes: a canister that adsorbs evaporated fuel generated within a fuel tank that is provided to a vehicle; a vapor passage that connects the canister and the fuel tank; a shutoff valve capable of closing off and opening up the vapor passage. When a specific event by which a current position of the shutoff valve becomes unknown occurs and initialization processing has become necessary, a first process is performed in which the shutoff valve is operated by a first operating amount that is set as an operating amount capable of operating the shutoff valve to an operation limit, irrespective of the current position, while, when the initialization processing has become necessary without the specific event occurring, a second process is performed in which the shutoff valve is operated by a second operating amount that is an operating amount from the current position to an initial position, and that is smaller than the first operating amount.