Piezoelectric Fuel Injector Valve Control via Segmented Charging
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Solution Overview
Problem
Existing fuel injection control devices face challenges in improving valve-opening response while preventing damage to piezoelectric elements due to load missing, which occurs from rapid changes in fuel pressure and inertial expansion.
Innovation Solution
A fuel injection control device with a valve opening control portion that includes a first rising control, a pause control, and a second rising control to manage the charging of the piezoelectric element, pausing the charge increase immediately before the control valve opens, thereby reducing the risk of load missing and enhancing valve-opening response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the rising speed of the voltage applied to the piezoelectric element is increased to improve valve-opening response, then the valve-opening response is improved, but load missing is generated which may cause damage to the piezoelectric element
Solution Approach 1:
The voltage application process is divided into multiple segments: a first voltage application period, a second voltage application period, and a third voltage application period. This segmentation allows the voltage to be applied in controlled stages, preventing sudden voltage spikes that cause load missing while still achieving rapid valve opening through the cumulative effect of the segmented voltage applications.
Solution Approach 2:
A preliminary voltage application is performed before the main voltage application to prepare the piezoelectric element for the subsequent rapid voltage change. This preliminary action reduces the shock and stress on the piezoelectric element when the main voltage is applied, preventing load missing while maintaining fast response.
2Speed
If the charge amount of the piezoelectric element is increased to improve valve-opening response, then the valve-opening response is improved, but the expanding force becomes excessive which may cause damage
Solution Approach 1:
The charge amount is increased in segmented steps rather than as a single large increment. Each voltage application period adds a controlled amount of charge, allowing the piezoelectric element to expand progressively. This prevents excessive expanding force that would occur with a single large charge application while still achieving the necessary total charge for rapid valve opening.
Solution Approach 2:
The voltage application strategy dynamically adjusts the charge amount based on the operational phase. During the first voltage application period, a moderate charge is applied to prepare the element. During the second period, the charge is increased to achieve rapid opening. During the third period, the charge is adjusted to complete the opening while preventing over-expansion. This dynamic adjustment optimizes both response speed and force control.
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 solution effectively restricts damage to the piezoelectric elements and improves valve-opening response by controlling the charging and discharging of the piezoelectric element, reducing load missing and enhancing the responsiveness of the valve, allowing for more precise and efficient fuel injection.
Implementation Method 1
a piezoelectric element opening the control valve when being electrically charged to expand
Data Source
AI summary
A fuel injection control device has a valve opening control portion which opens a control valve by electrically charging a piezoelectric element, and a valve closing portion which closes the control valve. The valve opening control portion includes a first rising control portion, a pause control portion and a second control portion. The first rising control portion increases a charge amount of the piezoelectric element during a first rising period. The pause control portion pauses an increase in the charge amount of the piezoelectric element during a pause period after the first rising period. The second rising control portion increases the charging amount of the piezoelectric elements again during a second rising period after the pause period. The pause period includes a period of immediately before the control valve is opened.