Piezo Servo Injector Force Connection
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Solution Overview
Problem
In injectors with a servo valve, the indirect connection between the piezo actuator and nozzle needle leads to slow and inaccurate regulation of fuel injection due to unknown idle travel of the piezo actuator, affecting the precision and robustness of fuel metering.
Innovation Solution
Establishing a permanent direct force connection between the piezo actuator and servo valve, allowing for real-time detection of changes in force and voltage, enabling precise regulation of injection parameters by eliminating idle travel and ensuring accurate feedback even at low operating pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a servo valve is used between the piezo actuator and nozzle needle, then the injector can control fuel injection, but the idle travel of the piezo actuator is unknown which reduces measurement precision and regulation accuracy
Solution Approach 1:
The patent applies feedback by detecting the force acting on the piezo actuator during operation. Sensors monitor the force changes in real-time, and this information is fed back to the control system to compensate for idle travel variations, thereby maintaining precise control despite the indirect connection through the servo valve
Solution Approach 2:
The patent changes the operational parameters by monitoring force, voltage, and capacitance variations of the piezo actuator. By detecting these parameter changes during different operational states (servo valve open/closed, nozzle needle closed), the system can calculate and compensate for idle travel, transforming an unknown parameter into a measurable and controllable one
2Manufacturing precision
If the piezo actuator remains in force contact with the servo valve after closure, then the nozzle needle closing time can be regulated, but the regulation speed is slow and accuracy depends on operating conditions
Solution Approach 1:
The patent applies preliminary action by pre-establishing a direct force connection between the piezo actuator and servo valve that remains active even when not strictly needed for valve actuation. This continuous force connection ensures that the piezo actuator is always ready to respond, eliminating delays associated with re-establishing contact and enabling faster regulation responses
Solution Approach 2:
The patent maintains continuous useful action by keeping the piezo actuator in permanent force contact with the servo valve throughout operation. This continuous connection eliminates idle travel variations and ensures uninterrupted force transmission, allowing for faster and more consistent regulation of nozzle needle closing time regardless of operating conditions
3Measurement precision
If a direct force connection is established between the piezo actuator and servo valve, then feedback accuracy improves, but the device complexity increases due to additional sensing and control requirements
Solution Approach 1:
The patent applies universality by making the piezo actuator serve dual functions: it acts as both the actuator that generates force and as a sensor that detects force changes. This multi-functionality eliminates the need for separate sensing components, reducing overall device complexity while maintaining high measurement precision through the direct force connection
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 solution achieves high accuracy and robustness in fuel metering by ensuring a consistent force connection, allowing for precise determination and regulation of injection times and quantities, improving the injector's performance across varying conditions.
Implementation Method 1
a piezo actuator with the expansion and contraction of said piezo actuator generating the opening and closing movement of the nozzle needle
Implementation Method 2
a change in force on the servo valve due to a change in pressure in the valve chamber when the servo valve is opened and closed and when the nozzle needle of the injector is closed is always transmitted to the piezo actuator as a change in force, and that the resulting change in voltage and/or capacitance of the piezo actuator is detected
Data Source
AI summary
The present disclosure provides a method for operating an injector of an internal combustion engine, the nozzle needle of said injector being operated by a piezo actuator by means of a servo valve. The method may include eliminating the idle travel of the piezo actuator by maintaining a permanent direct force connection between the piezo actuator and the servo valve, so that a change in force on the servo valve due to a change in pressure in the valve chamber when the servo valve is opened and closed and when the nozzle needle of the injector is closed is always transmitted to the piezo actuator as a change in force, detecting the resulting change in voltage and/or capacitance of the piezo actuator, and ascertaining parameters with which the injection quantity which is output by the injector is regulated based on the result of the detection.