Piezo Actuator Switching Time Evaluation for Injection Valve State
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining the state of an injection valve in internal combustion engines are complex due to sensitivity to interference variables, as they rely on feedback signals from piezo actuators that function as both actuators and sensors, making it difficult to accurately assess the nozzle needle position during the injection process.
Innovation Solution
The method involves evaluating the T on and/or T off switching times of a pulse-width-modulated piezo output stage, using comparator thresholds to reduce interference sensitivity, and measuring the ON and OFF times to derive the injection valve state, while considering the voltage difference and actuation path, potentially using a 2-quadrant buck or boost converter topology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback signals from piezo actuator are used to determine injection valve state, then measurement information is obtained, but sensitivity to interference variables increases and measurement precision deteriorates
Solution Approach 1:
The patent introduces an intermediary measurement approach by using the piezo actuator's electrical characteristics (impedance, voltage, current) as indirect indicators of nozzle needle position, rather than directly measuring mechanical position. This intermediary electrical measurement is less susceptible to interference from mechanical vibrations, thermal effects, and electromagnetic noise that plague direct mechanical sensing, thereby improving measurement precision while reducing interference sensitivity.
Solution Approach 2:
The patent replaces direct mechanical position measurement with electrical property measurement. By substituting mechanical sensors with electrical measurements of the piezo actuator's impedance, voltage, or current characteristics, the system eliminates the need for separate mechanical position sensors that would be highly sensitive to interference. This substitution maintains measurement capability while significantly reducing vulnerability to environmental interference variables.
2Measurement precision
If multiple influencing factors are considered in evaluation methods, then measurement completeness is improved, but device complexity increases
Solution Approach 1:
The patent extracts and isolates the most critical electrical characteristic (impedance, voltage, or current) of the piezo actuator that directly correlates with nozzle needle position. Instead of analyzing multiple influencing factors simultaneously, the method focuses on extracting this single dominant electrical parameter, thereby maintaining measurement precision while dramatically simplifying the evaluation methodology and reducing computational and hardware complexity.
Solution Approach 2:
The patent changes the measurement parameter from mechanical position to electrical property (impedance, voltage, or current). This parameter transformation allows the system to determine injection valve state through simpler electrical measurements rather than complex multi-factor analysis. The electrical parameters naturally encapsulate the effects of multiple influencing factors, enabling accurate state determination with reduced methodological complexity.
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 simplifies the identification of injection valve states by reducing interference variables, providing accurate assessments of valve states through pulse-width modulation and voltage difference analysis, leading to improved robustness and accuracy in determining the valve's operational conditions.
Implementation Method 1
the nozzle needle of the valve is activated by means of a piezo actuator
Data Source
AI summary
The present disclosure relates to internal combustion engines. The teachings thereof may be embodied in methods for determining a state of an injection valve of an internal combustion engine. Some methods may include actuating the piezo actuator in a pulse-width-modulated manner; recording the T on and/or T off switching times of the pulse-width-modulated piezo output stage of the piezo actuator; and evaluating the recorded switching times to derive the state of the injection valve.