Valve Lift Control via Movable End Stop Assembly
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Solution Overview
Problem
Existing flow control valves, particularly fuel injection valves, face challenges in achieving precise and simple control of valve member lift due to limitations in actuator displacement and oscillations introduced by spring-based end stops, which can result in inadequate fuel delivery at high engine loads.
Innovation Solution
An end stop assembly with two pieces actuated by an electromagnetic plunger, allowing for discrete valve member lifts by changing contact surfaces, is used to control the lift of the valve member, providing stable and accurate operation by minimizing oscillations and requiring less force to actuate the plunger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a spring-based end stop is used to limit valve member movement, then the valve member can achieve a predetermined lift position, but oscillations are introduced that reduce positioning precision
Solution Approach 1:
The patent removes the spring component from the end stop assembly entirely. The end stop is implemented as a fixed mechanical structure without elastic elements, thereby eliminating the source of oscillations while maintaining the ability to limit valve member lift to predetermined positions.
Solution Approach 2:
The end stop assembly is divided into multiple segments or surfaces at different positions along the valve member's travel path. Each segment corresponds to a specific lift position (e.g., first lift position, second lift position), allowing precise control at discrete points without requiring a continuous spring mechanism.
2Volume of moving object
If strain-type actuators (piezoelectric, magnetostrictive) are used to control valve member lift, then actuator size is reduced, but the achievable valve member lift becomes insufficient for high engine loads
Solution Approach 1:
The system dynamically switches between different end stop positions to achieve variable valve member lift. The end stop assembly can be positioned at different locations (first end stop position, second end stop position) to limit the valve member to different lift distances, allowing a compact actuator to achieve both small and large lifts as needed.
Solution Approach 2:
The lift range is segmented into discrete positions achieved by different end stop configurations. Rather than requiring a single large-stroke actuator, the system uses multiple discrete lift positions (first lift, second lift, third lift) that can be achieved with a smaller actuator by changing the end stop position.
3Length of moving object
If electromagnetic actuators are used to achieve larger valve member displacements, then sufficient fuel delivery is achieved, but the actuator complexity and size increase
Solution Approach 1:
The end stop assembly acts as an intermediary mechanism between the actuator and the valve member. It provides the additional function of limiting and positioning the valve member lift without requiring the actuator itself to be complex or large. The end stop absorbs the complexity of achieving precise positioning at multiple lift levels.
Solution Approach 2:
The system uses dynamic positioning of the end stop assembly to achieve variable lift. By moving the end stop between different positions (first, second, third end stop positions), the system achieves different valve member lifts with a relatively simple actuator, reducing overall system complexity compared to using a single large electromagnetic actuator for all lift positions.
4Manufacturing precision
If multiple electromagnetic actuators are used to achieve different valve member lift positions, then precise intermediate positions are achieved, but the device complexity increases significantly
Solution Approach 1:
The end stop assembly serves multiple functions: it limits valve member travel, defines precise lift positions, and can be repositioned to achieve different lift levels. This single multi-functional component replaces what would otherwise require multiple separate actuators, each dedicated to a specific lift position.
Solution Approach 2:
The end stop assembly acts as an intermediary that translates a single actuator's motion into multiple precise valve member lift positions. Rather than using multiple actuators to directly move the valve member to different positions, the end stop mediates this process by providing mechanical stopping surfaces at predetermined locations.
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 solution enables precise control of valve member lift, ensuring accurate fuel delivery at various engine loads without the oscillations and complexity associated with prior solutions, enhancing engine operation efficiency.
Implementation Method 1
The pieces are movable relative to each other and are actuated by an electromagnetic actuator
Implementation Method 2
An example of such fuel injection valves with an adjustable valve member lift are fuel injection valves actuated by a piezoelectric actuator
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
An apparatus for controlling the lift of a valve member in a flow control valve comprises an end stop assembly having at least two pieces, a plunger with one end interposed between these pieces and biasing members that urge the pieces into contact with the plunger. The plunger is movable by an actuator to thereby move the pieces of the end stop assembly from a first position in which the pieces of the end stop assembly form a first surface for contacting the valve member to a second position in which the pieces form a second surface that comes into contact with the valve member when the valve member is lifted from its seated position, to thereby allow different discrete lifts of the valve member.