Fuel Injection Controller Coil Current Control
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Solution Overview
Problem
The robustness of fuel injection control in internal combustion engines is compromised by variations in coil temperature, leading to inaccuracies in injection timing and amount, especially during multi-injection cycles.
Innovation Solution
A fuel injection controller that includes a boost circuit and control mechanisms to manage coil current, ensuring the initial-current applied time period is less than a threshold, thereby stabilizing the relationship between energization time and injection amount, regardless of coil temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the coil current is increased to a first target value I1 by boost voltage to achieve rapid valve opening, then the valve-opening response is improved, but the coil current must subsequently be reduced to a second target value I2 which complicates the control system
Solution Approach 1:
The patent segments the coil current control into two distinct phases: a first phase where current is rapidly increased to I1 for quick valve opening, and a second phase where current is reduced to and held at I2 for stable injection. This segmentation allows optimization of each phase independently, achieving fast response while maintaining simpler overall control through clear phase boundaries and target value switching.
2Temperature
If the coil temperature varies, then the resistance of the coil varies, but this causes the increasing slope of the electromagnetic attractive force to vary and delays valve opening
Solution Approach 1:
The patent implements feedback control by monitoring the actual coil current and comparing it to the target current values (I1 and I2). The controller adjusts the voltage applied to the coil based on the difference between actual and target current, ensuring that valve opening occurs at the correct timing regardless of temperature-induced resistance variations. This feedback mechanism compensates for temperature effects and maintains reliable injection control.
Solution Approach 2:
The patent changes the control parameter from direct voltage control to current-based control with specific target values. By controlling the coil current to reach specific target values (I1 for rapid opening, I2 for stable injection), the system compensates for temperature-induced resistance changes. The current target values are set to account for temperature effects, ensuring consistent valve opening timing across different operating temperatures.
3Loss of time
If the initial-current applied time period is not controlled to be less than a threshold, then the injection timing accuracy deteriorates due to temperature variations
Solution Approach 1:
The patent applies preliminary action by rapidly increasing the coil current to the first target value I1 before the actual valve opening occurs. This preliminary current application ensures that the electromagnetic attractive force reaches its maximum increasing slope before valve opening, compensating for temperature-induced delays. By preparing the coil current in advance to a higher target value, the system ensures accurate injection timing even when temperature causes resistance 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 approach enhances the robustness of fuel injection control by minimizing temperature-induced variations, improving accuracy and reliability of injection timing and amount, particularly in multi-injection scenarios.
Implementation Method 1
a fuel injector injecting fuel by a lift-up (valve-opening operation) of a valve body according to an electromagnetic attractive force generated by an energization of a coil
Data Source
AI summary
A fuel injection controller includes an increase control portion applying the boost voltage to the coil to increase a coil current to a first target value, and a constant current control portion applying a voltage to the coil to hold the coil current to a second target value. A threshold is an energization time period that is necessary to reach a boundary point between a seat throttle area of a property line and an injection-port throttle area of the property line from an energization start time point. An initial-current applied time period is from the energization start time point that the boost voltage starts to be applied to the coil to a time point that the coil current is decreased to the second target value. The increase control portion controls the coil current such that the initial-current applied time period is less than the threshold.