Fuel Injection Valve Control Device for Drive Current Variation
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Solution Overview
Problem
Variations in drive circuit devices and high voltage application lead to unstable behavior of fuel injection valves and variations in fuel injection amounts in cylinder direct-injection internal combustion engines, particularly during multi-stage injections.
Innovation Solution
A control device that stabilizes fuel injection valve behavior by detecting and correcting high voltage and drive current variations using a high voltage generator circuit, drive IC, and shunt resistor to ensure consistent fuel injection, employing a method to predict and adjust voltage based on device differences and injection intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a high voltage is applied to rapidly open the valve body, then the valve opening speed is improved, but the drive current varies due to device difference in the boosting circuit
Solution Approach 1:
The control device detects the actual drive current flowing through the fuel injection valve and compares it with the target drive current. Based on this feedback, the control device adjusts the drive voltage dynamically to compensate for device differences in the boosting circuit, ensuring consistent valve body behavior across different devices while maintaining rapid opening speed.
2Productivity
If multi-stage injection is performed with short injection intervals, then the productivity is improved, but the high voltage may not reach the target voltage due to adjacent injection intervals
Solution Approach 1:
The control device predicts the timing of subsequent injections based on the current injection cycle and the programmed injection schedule. Before the next injection occurs, the control device pre-charges the boosting circuit or adjusts the voltage buildup timing to ensure that the target high voltage is reached even when injection intervals are short and adjacent, thereby maintaining reliable injection performance at high productivity levels.
3Speed
If the drive current is increased to ensure rapid valve opening, then the valve response is improved, but the fuel injection amount varies due to circuit variations
Solution Approach 1:
The control device dynamically adjusts multiple parameters including drive voltage magnitude, pulse width duration, and current ramp rate based on detected drive current characteristics. By changing these parameters in real-time according to actual circuit conditions, the system maintains consistent fuel injection amounts while ensuring rapid valve response, compensating for manufacturing variations in the boosting and drive circuits.
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 control device effectively stabilizes fuel injection valve behavior and reduces fuel injection amount variations, ensuring precise control and minimizing bouncing issues during valve opening and closing, thereby improving fuel injection accuracy and consistency.
Implementation Method 1
a high voltage boosted to a given voltage on the basis of a battery voltage is applied to the fuel injection valve
Implementation Method 2
a fuel is injected from a fuel injection control device having a fuel injection valve electromagnetically driven
Implementation Method 3
a drive current of a fuel injection valve is detected
Data Source
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AI summary
A control device for an internal combustion engine is provided which can stabilize behavior when a fuel injection valve is opened, and reduce a variation in the amount of fuel injection of the fuel injection valve. A control device (200) for an internal combustion engine includes high voltage difference detection means (404) for obtaining a difference between a predetermined reference voltage (403) and a real high voltage detected by a high voltage detection means (402), drive current difference storage means (406) for storing in advance the amount of device difference variation of a real drive current detected by drive current detection means (408), and drive control value correction means (409) for correcting at least one of a target value of a drive current to a fuel injection valve (105) and a target value of a drive time, on the basis of at least one result of the high voltage difference detection means and the drive current difference storage means, and corrects a target control value of the fuel injection valve on the basis of at least one detection result of the variation of the detected high voltage and the variation of the current for driving the fuel injection valve.