Fuel Injection Control Unit Pulse Width Correction
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Solution Overview
Problem
In fuel injection devices where the valve body and movable iron core are relatively displaceable, the kinetic energy of the movable iron core after valve closure leads to unstable valve opening behavior and variations in fuel injection amount due to changes in the gap length and velocity during the run-up phase.
Innovation Solution
A control unit that splits the required fuel injection amount into multiple portions and adjusts the energization time of the drive current based on the pulse width of drive command pulses, correcting the subsequent drive command pulse width using the preceding pulse width and pulse interval to stabilize the fuel injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the movable iron core is configured to take a run-up stroke to improve valve opening responsiveness, then the valve opening speed is improved, but the fuel injection amount varies due to unstable valve opening behavior when the iron core is displaced during the run-up phase
Solution Approach 1:
The control unit predicts the injection amount based on the drive command pulse width and pulse interval before actual injection occurs. This preliminary prediction allows the system to compensate for the unstable valve opening behavior during the run-up phase, ensuring precise fuel injection amount control despite the movable iron core's displacement variations
Solution Approach 2:
The control unit uses feedback from the pulse interval (time between end of preceding pulse and start of subsequent pulse) to correct the subsequent drive command pulse width. This feedback mechanism compensates for variations in the movable iron core's position and velocity, maintaining stable fuel injection amounts while preserving the rapid valve opening response
2Manufacturing precision
If split injection is implemented to control fuel injection amount, then the fuel injection precision is improved, but the control complexity increases due to need to correct subsequent pulse width based on preceding pulse and pulse interval
Solution Approach 1:
The patent replaces complex mechanical adjustment mechanisms with an electronic control system that uses software algorithms to predict and correct injection amounts. The control unit calculates the required pulse width corrections based on pulse interval timing, substituting mechanical precision requirements with computational logic that is easier to implement and maintain
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 stabilizes the fuel injection amount by accounting for the gap and speed changes between the movable iron core and valve body, ensuring consistent fuel delivery in fuel injection devices with relatively displaceable components.
Implementation Method 1
a fixed iron core that attracts the movable iron core by passing a drive current through a coil
Data Source
AI summary
An object of the present invention is to promote the stabilization of the fuel injection amount in a fuel injection device in which a valve body and a movable iron core are configured to be relatively displaceable. In a control unit 120 of a fuel injection device 100 which includes a control part that controls the energization time of a current flowing through a coil 108 based on the pulse width of a drive command pulse, the control part is configured to be able to execute control to split a required fuel injection amount for one combustion cycle into portions and inject the portions in a plurality of times. In addition, in injections including a sequence of a preceding drive command pulse Pi1 and a subsequent drive command pulse Pi2, the control part acquires a preceding drive command pulse width Ti1 of the preceding drive command pulse Pi1 and a pulse interval Tint that is the time between the end time te1 of the preceding drive command pulse Pi1 and the start time ts2 of the subsequent drive command pulse Pi2, and corrects the subsequent drive command pulse width Ti2 of the subsequent drive command pulse Pi2 by using the preceding drive command pulse width Ti1 and the pulse interval Tint.