Solenoid Valve Controller Using Periodic Test Pulses
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Solution Overview
Problem
Existing methods for measuring the de-energized stroke of solenoid valves in fuel injectors are unreliable due to small current changes, making it difficult to accurately control fuel injection timing and quantity, which affects engine performance and emissions.
Innovation Solution
A controller that supplies pairs of solenoid operating pulses with varying time intervals to detect the return of the valve to its initial state, allowing for precise measurement of travel time and adjustment of fuel injection pulses to standardize 'end stop to end stop' timing across multiple valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a small current is added after the main current has been switched off to measure the de-energized impact point, then the measurement becomes possible, but the measurement reliability deteriorates due to difficulty in reliably measuring the small changes
Solution Approach 1:
The patent applies periodic action by using a sequence of test pulses with progressively decreasing intervals. The controller sends multiple test pulses to the solenoid valve, each separated by a smaller time interval than the previous one, creating a periodic testing pattern that allows detection of the return stroke timing through the advancing travel time of successive pulses
Solution Approach 2:
The patent implements feedback by measuring the travel time of each test pulse and comparing it with previous measurements. The controller detects when the travel time advances, indicating the valve has returned to its initial state, and uses this feedback information to determine the de-energized impact point timing and adjust the main current switching accordingly
2Measurement precision
If transducers are added to measure the valve motion directly, then the measurement accuracy improves, but the system cost and complexity increase considerably
Solution Approach 1:
The patent applies self-service by using the solenoid valve's own existing components (solenoid coil, valve mechanism) to perform the measurement function. The controller utilizes the valve's natural response to test pulses and its inherent electrical characteristics to detect return stroke timing, eliminating the need for external measurement transducers and making the system self-diagnosing
Solution Approach 2:
The patent implements universality by making the solenoid coil serve dual functions: actuating the valve during normal operation and serving as a test stimulus during calibration. The same hardware components are used for both control and measurement purposes, reducing system complexity while maintaining measurement capability
3Measurement precision
If the time interval between test pulses is reduced to detect return stroke, then the timing measurement precision improves, but the risk of interference with valve motion increases
Solution Approach 1:
The patent uses periodic action with progressively decreasing intervals between test pulses. Starting with larger intervals and progressively reducing them allows the system to find the optimal timing where the valve has fully returned to its initial state, achieving precise measurement without interfering with the valve's natural motion cycle
Solution Approach 2:
The patent applies dynamics by adaptively adjusting the test pulse intervals based on detected valve response. The controller dynamically modifies the time interval between successive test pulses, decreasing it progressively until the valve return is detected, thereby optimizing measurement precision while ensuring the valve has sufficient time to complete its motion cycle
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 enables accurate timing measurements and adjustments, improving engine performance by standardizing fuel injection, reducing emissions, and enhancing fuel economy while lowering hardware costs and diagnostic complexity.
Implementation Method 1
The solenoid is often combined with a two-position valve, whereby the valve is pulled by the solenoid (when energized)
Implementation Method 2
the method tries to measure the end of the solenoid movement by detecting a small change in the current to the solenoid caused by the back EMF when the solenoid stops moving
Data Source
AI summary
A controller moves a solenoid operated valve with a first solenoid operating pulse during a travel time. After a time interval, the controller applies a second pulse, which moves the valve towards its original position. The time interval may be varied, and a characteristic indicative of the return of the valve to the original position may be detected based on a comparison of the pulses.