Fuel Injector Spill Valve Control for Precise Pressure Dwell
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Solution Overview
Problem
Existing methods for controlling fuel injector pressure in internal combustion engines are inadequate, particularly in managing variations between individual injectors and achieving precise pressure control during closely-timed fuel injections.
Innovation Solution
A method involving applying a first current to a spill valve solenoid to move it to a closed position, reducing the current to achieve a partially-open position for a dwell duration, and then increasing the current to return the spill valve to the closed position, utilizing pressure-dwell relationship maps to optimize pressure control based on expected fuel pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If closely-timed fuel injections are performed, then injection frequency and productivity are improved, but pressure control precision deteriorates due to pulses in fuel
Solution Approach 1:
The spill valve is transitioned from a static fully-open or fully-closed state to a dynamic partially-open state, allowing continuous adjustment of fuel flow. By controlling the spill valve to remain partially open between injections, the system dynamically balances fuel pressure buildup, enabling high-frequency injections while maintaining precise pressure control through proportional flow regulation.
Solution Approach 2:
The system changes the operational parameter of the spill valve from binary (open/closed) to continuous (partially-open degree). By adjusting the spill valve opening degree as a variable parameter rather than a fixed state, the system can modulate fuel flow proportionally, thereby controlling injection pressure precisely even during closely-timed injections that would otherwise cause pressure pulses.
2Manufacturing precision
If injector pressure control is implemented, then injection timing and quantity control are improved, but device complexity increases due to additional control mechanisms
Solution Approach 1:
The spill valve system is designed to automatically regulate fuel pressure through its own operational characteristics rather than requiring external active control. By utilizing the spill valve's inherent ability to maintain a partially-open state and its natural flow characteristics, the system achieves pressure control through self-regulation, eliminating the need for additional sensors, actuators, or complex control algorithms.
3Manufacturing precision
If spill valve actuation timing is corrected, then injection timing precision is improved, but measurement and control difficulty increases
Solution Approach 1:
Pressure-dwell relationship maps are pre-established through characterization tests that correlate spill valve dwell duration with resulting fuel pressure. By performing this measurement and mapping work in advance rather than in real-time, the system creates a lookup table or database of pressure outcomes for different dwell durations, simplifying real-time control to merely selecting the appropriate pre-determined dwell time based on desired pressure.
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 allows for precise control of fuel injector pressure, optimizing injection efficiency and reducing emissions by minimizing pressure fluctuations, thereby enhancing engine performance and reducing wear.
Implementation Method 1
applying a first current to a spill valve solenoid to move a spill valve of the fuel injector to a closed spill position; reducing the first current applied to the spill valve solenoid to move the spill valve to an at least partially-open position
Data Source
AI summary
In one instance, disclosed herein is a method for controlling a fuel injector of an engine system, the method including: applying a first current to a spill valve solenoid to move a spill valve of the fuel injector to a closed spill position; reducing the first current applied to the spill valve solenoid to move the spill valve to an at least partially-open position; determining a dwell duration for the fuel injector based on an expected fuel pressure of the fuel injector; and after the determined dwell duration, increasing the first current applied to the spill valve solenoid to return the spill valve to the closed spill position.