Fuel Injector Pull-In Time Control for Linearity
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Solution Overview
Problem
Fuel injectors for internal combustion engines often operate in a non-linear fashion due to varying fuel pressures, leading to inconsistencies in fuel injection, particularly at higher pressures, which can result in significant variations in fuel delivery between cylinders.
Innovation Solution
A method and system for controlling fuel injector operation by dynamically adjusting the pull-in time based on fuel pressure, decreasing it with increasing pressure above a threshold and increasing it with decreasing pressure, using a pressure sensor and control circuit to ensure more linear fuel injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the pull-in time is kept constant, then the control system is simple, but fuel injection becomes non-linear at varying fuel pressures
Solution Approach 1:
The pull-in time is made dynamic rather than fixed. The control system automatically adjusts the pull-in time based on real-time fuel pressure conditions, transitioning from a static control parameter to a dynamic one that adapts to operating conditions, thereby achieving linear fuel injection across varying pressures
Solution Approach 2:
The invention changes the parameter of pull-in time from a constant value to a variable value that depends on fuel pressure. By modifying this temporal parameter based on pressure conditions, the system achieves consistent fuel injection linearity without requiring complete redesign of the control architecture
2Manufacturing precision
If the pull-in time is decreased with increasing fuel pressure, then fuel injection linearity is improved, but the control algorithm becomes more complex
Solution Approach 1:
The control system implements feedback by continuously monitoring fuel pressure and using this information to adjust the pull-in time. The pressure sensor provides real-time feedback to the control unit, which then modifies the injection timing parameters to compensate for pressure variations and maintain consistent fuel delivery
Solution Approach 2:
The control system performs self-adjustment based on pressure conditions without requiring external intervention. The control unit automatically modifies the pull-in time according to the detected fuel pressure, enabling the system to self-correct for pressure variations and maintain optimal injection linearity
Data Source
AI summary
The operation of a fuel injector for an internal combustion engine is controlled, wherein the fuel injector has an on time that includes a pull-in time during which injector current increases to a pull-in current followed by a hold time during which the injector current is limited to a hold current that is less than the pull-in current. A control circuit receives a pressure signal from a pressure sensor that corresponds to a pressure of fuel supplied to the fuel injector for injection into the engine, correlates the pressure signal with fuel pressure, and decreases the pull-in time with increasing fuel pressure.