Piezo-Servo Injector Minimum Injection Interval Determination
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Solution Overview
Problem
Existing methods for determining the minimum hydraulic injection interval in piezo-servo injectors are inefficient, leading to unnecessary loss of dwell times and potential merging of injection rates, due to conservative calibration and aging effects, which are not effectively compensated.
Innovation Solution
A method that determines the closing time of the nozzle needle based on the characteristic pressure profile in the control spring chamber, incrementally reduces the injection interval by advancing the actuation timing, and observes the pressure profile to find the smallest interval where the preceding injection's closure is detectable, accounting for variations and aging effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conservative calibration is used to prevent merging of injections, then injection reliability is improved, but dwell time is unnecessarily reduced
Solution Approach 1:
The patent implements dynamic determination of the minimum hydraulic injection interval by monitoring the actual closing time of the nozzle needle through pressure profile analysis. Instead of using a fixed conservative value, the system continuously adapts the injection interval based on real-time detection of needle closure events, allowing optimal dwell times while ensuring injection separation.
Solution Approach 2:
The system uses feedback from pressure sensors to detect characteristic pressure profiles during needle closure. This feedback mechanism allows the control unit to determine whether the previous injection has truly closed before initiating a new injection, enabling reliable injection separation without excessive dwell times.
2Productivity
If smaller injection intervals are implemented, then productivity is improved, but risk of injection merging increases
Solution Approach 1:
The system dynamically adjusts the injection interval based on actual needle closure detection rather than using fixed timing. This allows the system to implement the smallest possible injection intervals while maintaining reliable separation, as the control unit waits for confirmed closure signals before initiating new injections.
Solution Approach 2:
The patent replaces mechanical timing mechanisms with sensor-based detection of pressure profiles. By using pressure sensors to detect needle closure events and substituting mechanical wait-times with electronic detection and control, the system achieves higher injection frequencies with maintained reliability.
3Device complexity
If aging effects and component variations are not compensated, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The system performs self-calibration by using the injector's own pressure profile characteristics to determine needle closure timing. The control unit analyzes pressure profiles generated during normal operation to dynamically determine the minimum hydraulic injection interval, eliminating the need for external calibration equipment or complex adjustment mechanisms.
Solution Approach 2:
The patent compensates for aging effects and component variations by continuously monitoring changes in pressure profile characteristics. As components age or vary, the pressure profiles change, and the system adapts by detecting these changes and adjusting the minimum injection interval accordingly, maintaining precision without increasing 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 method allows for precise determination of the minimum hydraulic injection interval, ensuring optimal dwell times and system performance over the injector's lifespan by dynamically adjusting injection intervals and compensating for component variations and aging effects.
Implementation Method 1
a piezo actuator is lengthened by applying a voltage and as a result acts on a control valve (servo valve)
Implementation Method 2
a spring which is arranged in the control spring chamber brings about closing of the control spring chamber
Implementation Method 3
At the moment of the closing or braking of the nozzle needle in the seat, a pressure peak is generated in the control spring chamber
Data Source
AI summary
A method and a device for determining the minimum hydraulic injection interval of a piezo-servo injector are described. The closing time of the nozzle needle of the injector is determined on the basis of the characteristic pressure profile in the control spring chamber of the injector. By incrementally reducing the injection interval of a subsequent injection by successively advancing the timing of the start of actuation of a subsequent injection and continuing to observe the pressure profile in the control spring chamber, the smallest injection interval is obtained from the last iteration step in which closing of the nozzle needle of the preceding injection could still be detected in the characteristic pressure profile. Particularly precise determination of the minimum injection interval is possible with this method.