Fuel Injector Energization Timing for Movable Core Return Stability
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Solution Overview
Problem
Fuel injection systems face issues with erratic fuel injection due to undershoot and overshoot conditions, where the movable core fails to return to its initial position correctly, leading to accidental fuel injection.
Innovation Solution
A fuel injection control device that includes additional energization, intermediate driving energization, and pre-energization strategies to manage the electromagnetic attracting force, ensuring the movable core returns to its initial position within the correct time frame, preventing erratic injections by adjusting the energization timing and magnitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the movable core is attracted by the fixed core to move the valve body in the valve opening direction, then fuel injection is achieved, but the movable core may fail to return to its initial position correctly causing erratic fuel injection
Solution Approach 1:
The valve body biasing member applies a preliminary counteracting force in the valve closing direction to prevent the movable core from failing to return to its initial position. This biasing member continuously exerts a restoring force that counteracts the electromagnetic attracting force, ensuring the movable core returns to its initial position after fuel injection and preventing erratic fuel injection.
Solution Approach 2:
The valve body biasing member acts as an intermediary element between the movable core and the valve body. It transmits the electromagnetic attracting force from the movable core to the valve body while simultaneously providing a restoring force to return the movable core to its initial position, thus mediating the interaction and ensuring stable operation.
2Reliability
If additional energization strategies are applied to ensure the movable core returns to its initial position, then erratic fuel injection is prevented, but the device complexity increases
Solution Approach 1:
The valve body biasing member provides a self-service mechanism that automatically returns the movable core to its initial position without requiring complex external control systems. The biasing member continuously exerts a restoring force that passively ensures the movable core returns to its initial position, eliminating the need for additional active control mechanisms.
Solution Approach 2:
The valve body biasing member enables periodic action by continuously cycling between the valve opening and closing positions. The biasing member ensures that after each fuel injection event, the movable core automatically returns to its initial position, creating a reliable periodic cycle of fuel injection without requiring complex control intervention.
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 proposed solution effectively prevents erratic fuel injections by ensuring the movable core returns to its initial position accurately, maintaining consistent fuel injection intervals and preventing accidental fuel delivery.
Implementation Method 1
a fixed core configured to generate an electromagnetic attracting force on energization of a coil
Implementation Method 2
a valve body biasing member that biases the valve body in a valve closing direction opposite to the valve opening direction
Data Source
AI summary
A fuel injection control device includes an additional energization unit. Concerning an undershoot state caused by a first energization for fuel injection, a return period is an estimated period required for a movable core to return to an initial position from a first energization. An injection interval ranges from the first energization to a second energization that is for a next fuel injection. An allowable period is obtained by subtracting a rise period estimated for the second energization from the return period. The additional energization unit adds an additional energization between the first energization and the second energization when the injection interval is longer than or equal to the allowable period and is shorter than or equal to the return period.