Combined Check Control Valve Sticking Prevention
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Solution Overview
Problem
Existing check and control valves for internal combustion engines face issues with the check plate sticking to the valve seat due to soot deposits or freezing, leading to operational failures and additional manufacturing costs from PTFE coatings, which can result in unintended openings and reduced service life.
Innovation Solution
A combined check and control valve design where the stop on the valve rod presses against the check plate beyond the nominal stroke to release it from the valve seat, using a guide element on the valve rod to prevent sticking and incorporating a solenoid or pneumatic actuator for controlled operation, with a position control system for precise positioning and a helical spring for uniform loading, avoiding the need for additional components and manufacturing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the check plate is biased against the valve seat by a spring element to prevent return flow, then the valve reliability improves, but the check plate tends to stick to the valve seat due to soot deposits or freezing
Solution Approach 1:
A guide element is introduced as an intermediary component between the check plate and the valve rod. This guide element prevents direct contact and sticking between the check plate and valve rod surfaces, allowing the check plate to slide smoothly during operation while maintaining the spring biasing force for reliability.
Solution Approach 2:
The solution moves from a single-point contact configuration to a guided linear motion configuration. The guide element constrains the check plate to move along a defined path, separating the sealing function (check plate to valve seat) from the actuation function (check plate to valve rod), thereby preventing sticking while maintaining reliability.
2Object-affected harmful factors
If PTFE coating is applied to valve seats to prevent sticking, then the sticking problem is reduced, but additional manufacturing steps and costs are incurred
Solution Approach 1:
The guide element serves as a mechanical intermediary that prevents sticking through proper alignment and separation of components, eliminating the need for PTFE coatings or other surface treatments. This mechanical solution is simpler to manufacture and maintain.
Solution Approach 2:
The guide element is a simple, inexpensive mechanical component that can be easily manufactured from common materials. It provides sticking prevention through its geometric design rather than expensive coatings, making it more cost-effective for long-term operation.
3Object-affected harmful factors
If the stop is positioned to allow full stroke movement, then the check plate can be released from sticking, but the nominal stroke is influenced and flow characteristics change
Solution Approach 1:
The guide element acts as a mediator that allows the check plate to slide freely along the valve rod without sticking, while the stop only engages to provide a maximum travel limit. This separation of functions (guiding vs. limiting) allows full stroke movement for release without compromising nominal stroke precision.
Solution Approach 2:
The valve rod stroke is segmented into a nominal operating stroke and a maximum release stroke. The guide element ensures smooth operation during the nominal stroke, while the stop provides a hard limit for the maximum stroke position, allowing the check plate to be released from sticking without affecting normal operation.
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
The design ensures reliable release of the check plate, preventing unintended openings and maintaining function despite ice or soot accumulation, while being economically manufactured and having a long service life, with precise control over valve positions to ensure efficient secondary air supply and pollutant reduction.
Implementation Method 1
a spring element supported, on its axially opposite side, on a limiting element
Implementation Method 2
opening the valve beyond the nominal stroke up to a maximum stroke causes the stop to be pressed against the check plate by the force of the actuator
Implementation Method 3
a guide element on the valve rod, on which element the check plate slides. Such a guide element prevents a sticking of the check plate to the valve rod
Data Source
AI summary
To overcome problems concerning the sticking of the check plate in a combined check and control valve, a stop is provided on the valve rod or a guide element in the vicinity of the valve rod, whose distance to the limiting element is smaller than the maximum stroke and larger than the nominal stroke of the limiting element. Thus, it is achieved that the check plate is released from the valve seat by means of the stop, when the valve rod is displaced to the maximum.