Fuel Vapor Valve Learning Control via Variable Speed
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Solution Overview
Problem
Existing fuel vapor processing apparatuses require a long time to accurately learn the valve opening start position due to a fixed speed of changing the closing valve's opening degree, which affects the efficiency of reducing internal fuel tank pressure.
Innovation Solution
A control device is implemented to perform a learning control by changing the stroke distance of the movable valve member at different speeds, moving at a higher speed to reach the learning start position and then at a lower speed to accurately determine the valve opening start position, thereby reducing the time required for learning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the opening degree of the closing valve is changed at a fixed speed, then the learning control can be performed with simple control logic, but it takes a relatively long time to accurately learn the valve open start position
Solution Approach 1:
The patent applies dynamics by changing the valve opening speed from a fixed constant to a variable speed profile. The control device increases the opening speed when the valve is far from the open start position, then reduces speed as it approaches the target position. This dynamic speed adjustment allows the system to cover the travel distance quickly while still achieving accurate positioning, resolving the contradiction between learning time and position accuracy.
Solution Approach 2:
The patent changes the parameter of valve opening speed from a static fixed value to a dynamic variable value. By adjusting the opening speed parameter based on the current position relative to the target position, the system optimizes both the time required to reach the target and the accuracy of arrival. This parameter change enables the valve to move quickly initially and then slow down for precise positioning.
2Measurement precision
If the opening degree of the closing valve is changed at a relatively low speed, then the valve open start position can be learned with high accuracy, but it takes a relatively long time to complete the learning control
Solution Approach 1:
The patent uses dynamic speed control to adjust the valve opening rate during the learning process. Instead of maintaining a uniformly low speed throughout the entire opening stroke, the system employs high speed during the initial phase and transitions to low speed only when approaching the valve open start position. This dynamic adjustment maintains high measurement precision during the critical positioning phase while improving overall learning control efficiency through faster initial movement.
Solution Approach 2:
The patent segments the valve opening process into multiple phases with different speed requirements. The first phase involves rapid opening movement to cover the majority of the travel distance quickly, while the second phase involves slowed movement for accurate positioning at the valve open start position. This segmentation allows the system to optimize for both speed and accuracy in different stages of the same process, improving overall productivity without sacrificing precision.
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 allows for accurate learning of the valve opening start position in a shorter time, improving responsiveness to internal pressure changes and minimizing the difference between determination and actual opening times, thus enhancing learning accuracy.
Implementation Method 1
a canister for adsorbing fuel vapor generated in a fuel tank
Data Source
AI summary
A fuel vapor processing apparatus may include a canister, a closing valve provided in a vapor passage connecting the canister and the fuel tank, an actuator coupled to the movable valve member, and a control device coupled to the actuator. The control device may perform a learning control, in which a valve opening start position is learned based on a stroke distance of the movable valve member, which is given at the time when an internal pressure of the fuel tank is reduced by a predetermined pressure value while the moving distance of the movable valve member is changed such that (a) the movable valve member moves from the reference position to a learning start position at a first speed in a valve opening direction and (b) the movable valve member moves further from the learning start position at a second speed in the valve opening direction.