Fuel Injection Control Device Voltage Switching
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Solution Overview
Problem
The voltage source for fuel injection devices varies during energizing and de-energizing, leading to deviations in the current supplied to the coil, which destabilizes the valve behavior and increases the deviation of the injection amount.
Innovation Solution
A control device that applies a predetermined voltage to the coil until the drive current reaches a maximum current, then lowers the current before the valve reaches the desired maximum lift position, and maintains a constant voltage or 0V until the valve reaches the desired position, stabilizing the valve behavior and reducing injection amount deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the current is stopped before the movable element reaches the fixed core to enable controllable injection, then the injection amount can be controlled, but the movable element opening is delayed and the operation becomes unstable
Solution Approach 1:
The patent applies dynamic voltage control by switching between high voltage and low voltage modes. The controller dynamically adjusts the voltage applied to the coil based on the injection phase: high voltage during initial opening for rapid response, and low voltage during injection control for stability. This dynamic voltage adjustment resolves the contradiction between achieving controllable injection amounts and maintaining operation stability.
2Speed
If high voltage is applied to make the valve move quickly from closed to open state, then the response speed is improved, but the voltage source varies during energizing and de-energizing causing current deviation
Solution Approach 1:
The patent implements periodic voltage switching with two distinct phases: a high-voltage phase for rapid valve opening and a low-voltage phase for stable injection control. The controller periodically switches between these voltage levels, applying high voltage only during the initial opening phase and then transitioning to low voltage for the remainder of the injection process. This periodic action achieves both fast response and current stability.
3Manufacturing precision
If the movable element and valve move parabolically with half lift condition, then the injection can be controlled, but the displacement is not restricted to fixed core and operation is easily influenced by environmental changes
Solution Approach 1:
The patent changes the voltage parameter dynamically during the injection process. By switching from high voltage to low voltage, the system adjusts the magnetic force characteristics to maintain stable operation. This parameter change compensates for environmental variations and ensures consistent injection control regardless of external conditions such as voltage fluctuations or temperature changes.
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 valve behavior and reduces the deviation of the injection amount, even when the voltage source voltage varies, ensuring consistent and accurate fuel injection.
Implementation Method 1
A valve and a coil to generate a magnetic attraction force attracting a movable portion to drive the valve
Implementation Method 2
A magnetic attraction force is generated between the fixed core and the movable element by supplying a current to the coil. The movable element moves in the opening direction at the time when the magnetic attraction force exceeds the force in the closing direction.
Data Source
AI summary
Provided is a control device of a fuel injection device which can stabilize a behavior of a valve even when a voltage of a voltage source varies, and can reduce a deviation of an injection amount. The fuel injection device includes a valve and a coil which generates a magnetic attraction force to attract a movable element which drives the valve. A control device applies a predetermined voltage to the coil on the basis of an injection pulse, causes a drive current to flow to the coil until the drive current reaches a maximum current, drives the valve by attracting the movable element, and injects fuel. The drive current flowing to the coil is lowered from the maximum current before the valve reaches a desired maximum lift position, and a constant voltage lower than a predetermined voltage or 0 V is continuously applied to the coil until the valve reaches the desired maximum lift position.