Fuel Injection Valve Two-Stage Throttle Mechanism
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Solution Overview
Problem
Conventional fuel injection valves experience instrumental error variations in injection amount due to complex throttle mechanisms, leading to inaccurate fuel injection, as the throttle portion changes in three stages during valve operation, affecting the fuel flow rate and resulting in deposit accumulation and altered spray shapes.
Innovation Solution
The fuel injection valve design is modified to change the throttle portion in two stages, specifically from a seat portion throttle state to an injection hole throttle state, reducing instrumental error variations by optimizing the seat and injection hole geometries and using a curved seat surface to minimize leakage and deposit formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a complex three-stage throttle mechanism is used, then the fuel injection valve can control fuel flow, but instrumental error variations increase and injection accuracy deteriorates
Solution Approach 1:
The throttle mechanism is segmented into two distinct stages: seat portion throttle state and injection hole throttle state. This segmentation allows each stage to be optimized independently, with the seat portion controlling initial fuel flow and the injection hole providing precise final metering, thereby reducing instrumental error variations while maintaining control capability.
Solution Approach 2:
The patent changes the geometric parameters of the seat surface and injection hole to optimize the two-stage throttle effect. By adjusting the seat surface curvature, elevation, and injection hole dimensions, the system achieves precise fuel flow control with minimal instrumental errors, transforming the control mechanism into a more accurate system.
2Productivity
If the throttle portion changes in three stages, then fuel flow rate can be controlled, but deposit accumulation increases and spray shape is altered
Solution Approach 1:
The patent extracts and eliminates one of the three throttle stages, simplifying the mechanism to two stages. This removal of an intermediate throttle stage reduces the number of places where fuel can stagnate and form deposits, while still maintaining effective fuel flow rate control through the optimized seat and injection hole geometries.
Solution Approach 2:
The seat surface is designed with a curved geometry rather than a flat surface. This curvature facilitates smoother fuel flow and reduces stagnation zones where deposits would form. The curved seat surface worksmates with the injection hole geometry to create a streamlined flow path that minimizes deposit accumulation while maintaining precise fuel flow control.
3Object-generated harmful factors
If the seat surface geometry is optimized to minimize leakage, then deposit formation is reduced, but manufacturing complexity increases
Solution Approach 1:
The seat surface geometry is designed in advance with predetermined curvature and elevation characteristics that are optimized to prevent leakage and deposit formation. By incorporating these geometric features into the mold or machining program from the outset, the complex curved surfaces can be manufactured efficiently without requiring post-processing or complex assembly steps.
Data Source
AI summary
A valve body has a seat surface swollen toward a seating surface of an injection hole body having an injection hole. A fuel passage is between the injection hole body and the valve body and is opened and closed due to separation and seating of the seat surface. In a seat portion throttle state, a flow rate of injected fuel is throttled by a gap between the seat surface and the seating surface. In an injection hole throttle state, the flow rate of fuel is throttled by the injection hole. When the valve body is operated from a valve closing position to a full lift position, the seat portion throttle state is brought from the valve closing position to a predetermined intermediate position, and the injection hole throttle state is brought from the intermediate position to the full lift position.