Fuel Injection Valve Closing Time Detection via Magnetic Coupling
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Solution Overview
Problem
Existing methods for determining the closing time of an injection valve in fuel injection systems are inaccurate due to various influencing factors, such as manufacturing tolerances, wear, and pressure waves, especially when the valve is actuated indirectly via a servo valve, leading to inaccuracies in fuel quantity injection.
Innovation Solution
A fuel injection valve with a solenoid valve that includes an armature bolt supported by a spring element, where the spring element is coupled with a magnetic circuit, causing a detectable parameter change upon elastic deformation, allowing for precise detection of the closing time without additional components or electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the closing time is determined via the position of the armature of the solenoid valve, then the opening duration can be controlled, but faults and deviations within the high-pressure hydraulic system cannot be detected
Solution Approach 1:
The patent introduces an armature bolt as an intermediary element that transmits the hydraulic pressure from the control chamber to the solenoid valve armature. This bolt is supported by a spring element that couples it to the magnetic circuit, allowing the closing time to be detected through magnetic parameter changes while maintaining the control function. The intermediary structure enables both control and precise detection simultaneously.
Solution Approach 2:
The patent replaces direct mechanical position sensing with a magnetic field-based detection system. The spring element couples the mechanically moving armature bolt to the magnetic circuit, where the elastic deformation of the spring causes detectable parameter changes in the magnetic circuit (such as inductance or magnetic flux changes). This substitution allows non-contact, precise detection of the closing time without additional electrical connections or complex mechanical sensors.
2Measurement precision
If an eddy current sensor with a measuring body is used to detect the end of injection, then the closing time can be detected, but additional components and separate electrical connections are required increasing design effort
Solution Approach 1:
The patent merges the detection function with the existing solenoid valve structure. The spring element that is already part of the solenoid valve's mechanical structure is used to couple the armature bolt to the magnetic circuit. This integration allows the detection function to be embedded within the existing components, eliminating the need for separate measuring devices and their associated electrical connections.
Solution Approach 2:
The magnetic circuit in the solenoid valve is given a dual function: it serves both the actuation function (generating magnetic force to open/close the valve) and the detection function (sensing the closing time through parameter changes). The spring element enables this multi-functionality by transmitting mechanical motion to the magnetic circuit, allowing the same component to perform both control and measurement tasks.
3Ease of manufacture
If manufacturing tolerances and wear are present in the switching chain, then the injection valve can be manufactured with standard tolerances, but inaccuracies in injected fuel quantity occur
Solution Approach 1:
The patent implements a feedback mechanism by detecting the actual closing time of the injection valve through the magnetic parameter changes in the solenoid valve's magnetic circuit. This detected closing time information can be used to compensate for variations caused by manufacturing tolerances and wear in the switching chain (actuator, servo valve, high-pressure hydraulic system). The feedback allows for real-time adjustment or correction of the injection duration calculation, maintaining accuracy despite component variations.
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 solution enables accurate determination of the closing time of the injection valve, compensating for dynamic behavior and inaccuracies in the switching chain, resulting in improved precision in fuel quantity control.
Implementation Method 1
the spring element and a coil of at least one magnetic circuit are coupled and which cause a detectable parameter change, preferably a change in the coil voltage or the coil current, in at least one magnetic circuit when the spring element is elastically deformed
Implementation Method 2
coupling means are provided via which the spring element and a coil of at least one magnetic circuit are coupled and which cause a detectable parameter change, preferably a change in the coil voltage or the coil current, in at least one magnetic circuit when the spring element is elastically deformed
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The method involves controlling an injection valve member by a solenoid valve whose anchor bolt is axially and displaceably mounted on a spring element (4). The anchor bolt is made to impact by axial force that is directly proportional to hydraulic pressure in a control chamber (3). The spring element and coils (7) of magnetic circuits are coupled by a coupling unit (6). Detectable parameters change such as change of coil voltage or coil current are caused in the magnetic circuits during elastic deformation of the spring element over the coupling unit. An independent claim is also included for a fuel injection valve for injecting fuel into a combustion chamber of an internal combustion engine.