Piezo-Actuated Injection Valve Bounce Control
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Solution Overview
Problem
Bounce effects in piezo-actuated injection systems of internal combustion engines lead to instability, inaccurate fuel quantity delivery, and unwanted pressure waves, affecting the system's operational behavior and requiring compensation for age-related and tolerance issues across engine cylinders.
Innovation Solution
A method that detects the actual bounce behavior of the control valve and offsets it by influencing the speed characteristic of the needle, using a stop phase in the charging and discharging operations of the piezo actuator to minimize deviations between actual and desired bounce behaviors, thereby reducing bounce-related instability through optimized control of the piezo actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the control valve is actuated by a piezo actuator to enable precise fuel injection control, then the injection accuracy is improved, but bounce effects occur causing instability and inaccurate fuel quantity delivery
Solution Approach 1:
The method applies preliminary action by detecting bounce effects and compensating for them in advance through a stop phase in the charging operation. The control device minimizes areas between the capacitance characteristic and reference line by adjusting the stop phase duration, which prevents bounce-induced instability before it affects fuel injection accuracy
Solution Approach 2:
The invention implements feedback by continuously monitoring the capacitance characteristic of the piezo actuator to detect bounce effects. The control device uses this feedback information to adjust the charging operation parameters, specifically the stop phase duration, thereby maintaining stable operation while preserving injection precision
2Speed
If the needle speed is increased to improve response time, then the injection response is improved, but bounce effects are intensified causing unstable pressure buildup behavior
Solution Approach 1:
The method applies periodic action by introducing a stop phase into the charging operation of the piezo actuator. This periodic interruption in the charging process allows the needle to decelerate before reaching the valve seat, reducing bounce effects while maintaining overall fast response. The stop phase duration is dynamically adjusted based on detected bounce characteristics
Solution Approach 2:
The invention changes parameters by dynamically adjusting the stop phase duration in the charging operation based on real-time detection of bounce effects. The control device modifies the charging parameters to minimize areas between the capacitance characteristic and reference line, thereby optimizing the balance between needle speed and pressure buildup stability
3Loss of time
If the control valve switching is made faster to improve injection timing precision, then the timing accuracy is improved, but unwanted pressure waves are generated in the injection system
Solution Approach 1:
The method applies preliminary action by detecting potential pressure wave generation and compensating in advance through adjusted stop phase timing. The control device modifies the charging operation to reduce needle impact velocity, preventing pressure wave generation before it occurs, while maintaining precise injection timing through optimized stop phase duration
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 effectively minimizes bounce effects, stabilizing the operational behavior of the injection system, ensuring accurate fuel delivery and reducing pressure wave occurrences, while adapting to changes in bounce patterns over time.
Implementation Method 1
Pump-injector units (PDE) with a control valve actuated by a piezo actuator as an actuating element
Implementation Method 2
areas between a capacitance characteristic of the piezo actuator and a reference line connecting the maxima of the capacitance characteristic
Data Source
AI summary
The invention relates to a method and a device for offsetting bounce effects in a piezo-actuated injection system of an internal combustion engine using a control valve actuated by a piezoelectric actuator. The inventive method comprises the following steps: detecting an actual bounce behavior of the control valve, and determining and offsetting a deviation between the actual bounce behavior and a desired bounce behavior of the control valve, thereby generating an actuation information for the control valve which influences a speed characteristic of a needle of the control valve. The invention also relates to a device for carrying out the inventive method.