Solenoid Valve Controller for Fuel Injection Systems
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Solution Overview
Problem
Existing solenoid valve control systems in fuel injection systems do not adequately account for engine operating conditions and solenoid coil resistance when determining the need for additional voltage pulses, leading to potential coil damage and compromised valve performance, especially during low battery voltage conditions such as engine starting in cold temperatures.
Innovation Solution
A controller that measures voltage and current across the solenoid coil and uses this data to determine the resistance of the actuator, applying control functions to manage voltage pulses and maintain current within defined thresholds, including the use of Boost voltage pulses to support the solenoid coil during low battery conditions, thereby reducing power drawn from the boost capacitor and minimizing coil stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional Boost voltage pulses are applied to maintain solenoid current during low battery voltage, then valve performance is maintained, but solenoid coil resistance variations cause improper activation and potential coil damage
Solution Approach 1:
The controller measures the actual current through the solenoid coil and uses this feedback to determine when to activate additional Boost voltage pulses. The controller calculates solenoid resistance from measured voltage and current values, and compares actual current against target current thresholds to dynamically control Boost circuit activation, preventing both under-performance and over-stressing the coil
Solution Approach 2:
The system dynamically adjusts the activation threshold for Boost voltage pulses based on measured solenoid resistance. Instead of using a fixed voltage threshold, the controller calculates a resistance-specific threshold voltage that accounts for temperature and operating condition variations, allowing precise control under varying conditions
2Device complexity
If solenoid coil resistance is not accounted for in control decisions, then control logic is simpler, but current management becomes inadequate leading to compromised valve performance
Solution Approach 1:
The controller continuously measures voltage across and current through the solenoid coil, calculating actual resistance in real-time. This feedback mechanism allows the system to adapt to resistance changes due to temperature and operating conditions, maintaining reliable current management without requiring complex pre-programmed resistance compensation tables
Solution Approach 2:
The system uses the solenoid's own electrical characteristics (measured voltage and current) to automatically determine its resistance state and adjust control parameters accordingly. The solenoid effectively monitors itself, eliminating the need for external sensors or complex control logic while maintaining optimal performance
3Reliability
If solenoid current is reduced by half, then coil stress is minimized and system costs are reduced, but voltage supply capability must be maintained during low battery conditions
Solution Approach 1:
The controller applies Boost voltage pulses periodically during the hold phase rather than continuously. By timing these pulses to coincide with periods when battery voltage naturally dips or when current approaches the lower threshold, the system maintains adequate power supply with reduced average current draw, minimizing coil stress while ensuring performance
Solution Approach 2:
The system dynamically adjusts the timing and frequency of Boost voltage pulse application based on real-time current measurements and calculated resistance. This dynamic control allows the system to maintain sufficient power supply capability only when needed, rather than operating at high current continuously, thereby protecting the coil while maintaining voltage supply readiness
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 effectively reduces the operating current of solenoid coils by half compared to existing systems, allowing solenoids to be designed for normal voltage operation, reducing system costs and preventing coil damage, while maintaining valve performance across varying engine conditions.
Implementation Method 1
an electromagnetic stator (a series of coil windings wound around a stator core), through which a current is passed to activate an armature
Implementation Method 2
The driving current provided during the pull-in phase is supplied by a capacitor. The capacitor and associated circuitry provide a further voltage supply means
Implementation Method 3
The valve pin is held in the open position by a return spring, therefore any electromagnetic force induced by the solenoid coil is working against the spring to close the valve
Data Source
AI summary
A controller for controlling the operation of a valve in an engine system, the valve being in communication with a battery and a further voltage supply means and comprising an actuator, the controller comprising inputs for receiving data representing the voltage across the battery and further voltage supply means and the current through the actuator; a processor programmed to determine a control function for controlling the operation of the valve in dependence on the voltage across the further voltage supply means and the current through the actuator; and outputs for outputting the control function as determined by the processor to the battery and further voltage supply means.