Piezo Actuator Valve Inversion for Pressure-Stable Control
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Solution Overview
Problem
Standard piezo-servo-driven injectors face challenges in controlling valve position stability and pressure across a wide range, leading to inefficient fuel consumption and the need for additional components like pressure control valves for dynamic leakage management.
Innovation Solution
An actuator with a valve unit design that incorporates a piezo element, a force transmission device, and prestressing elements, allowing the valve to operate with pressure rather than against it, using the piezo element's movement to lift the valve element off the seat and control valve position through the applied pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard piezo-driven injector is used, then the valve can be actuated against existing pressure, but the valve position becomes unstable and inconsistent at high pressure, making it difficult to control within a small displacement range
Solution Approach 1:
The patent inverts the conventional approach by having the piezoelectric element move the actuator housing away from the valve element when activated, rather than pushing it toward the valve. This reversal allows the valve to open in the direction of applied pressure, stabilizing valve position control across the entire pressure range and eliminating the need for separate pressure control valves.
Solution Approach 2:
The piezoelectric actuator is designed to perform multiple functions: it controls valve opening/closing and simultaneously manages pressure regulation and dynamic leakage without injection. By integrating these functions into a single actuator design, the system eliminates the need for separate pressure relief valves and pressure control valves, reducing overall device complexity.
2Reliability
If a pressure relief valve and pressure control valve are added to manage dynamic leakage, then pressure control across the entire pressure range is achieved, but the device complexity increases and fuel consumption becomes suboptimal
Solution Approach 1:
The patent merges the functions of the piezoelectric actuator with pressure control and dynamic leakage management. The single actuator integrates the piezoelectric element, actuator housing, and valve element interaction to simultaneously achieve valve actuation and pressure regulation, eliminating the need for separate pressure relief and pressure control valves.
Solution Approach 2:
The piezoelectric actuator is designed as a multi-functional component that performs valve actuation, pressure control, and dynamic leakage management. This universal design reduces the total number of components needed in the injection system while maintaining reliable pressure control across the entire operating range.
3Ease of operation
If the piezoelectric element moves the actuator housing towards the valve element, then the valve opens, but the valve position is unstable at high pressure due to pressure-dependent effects
Solution Approach 1:
The patent inverts the conventional actuation direction: when the piezoelectric element is activated, it causes the actuator housing to move away from the valve element, allowing the valve to open in the direction of applied pressure. This inversion stabilizes valve position consistency across the entire pressure range by eliminating pressure-dependent instability.
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 design achieves stable valve control and eliminates the need for pressure relief and control valves, optimizing fuel consumption and simplifying the injector system by leveraging the robustness of solenoid valves and the precision of piezo actuators.
Implementation Method 1
a piezoelectric element arranged between the fixed base plate and a head plate of the movable actuator housing... an increase in length of the piezoelectric element makes the actuator housing movable
Data Source
Figure 1~2
AI summary
The invention relates to an actuator with a valve unit for a piezo servo-operated injector. The actuator has an outer housing with a base plate and an actuator housing which can be moved by the base plate and in which a piezo element is arranged. By lengthening the piezo element, the actuator housing is moved and in the process lifts a valve element up from a valve seat via a force transmission device. The valve element is therefore moved in the direction of the applied pressure during an opening process. In this manner, an improved control of the valve in comparison to the prior art is achieved because it is not necessary to work against the applied pressure.