Pressure Sensor Calibration in High-Pressure Injection Systems
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Solution Overview
Problem
In high-pressure injection systems of internal combustion engines, pressure sensors can become incorrectly calibrated, leading to inaccurate fluid pressure readings, which can result in improper adjustment of the inlet valve and subsequent fluid pressure, affecting engine performance.
Innovation Solution
A method is implemented to detect incorrectly calibrated pressure sensors by applying a measurement current to the electromagnet while the inlet valve is closed, detecting the opening position of the piston based on a predetermined change in the measurement current over time, and checking if the change in opening position corresponds to a predetermined setpoint value change, generating a fault signal if the correspondence criterion is not met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is used to monitor fluid pressure in a high-pressure injection system, then the fluid pressure can be adjusted to a setpoint value, but the sensor signal may become incorrect due to calibration changes or deliberate adjustment, leading to wrong pressure readings
Solution Approach 1:
The patent applies preliminary action by performing a calibration check before the pressure sensor's incorrect calibration causes engine performance problems. The control device executes a calibration check method that detects calibration changes by comparing measured opening positions with expected values, thereby identifying sensor issues before they lead to harmful effects.
2Ease of operation
If the inlet valve is closed by applying current to an electromagnet during piston movement to adjust fluid pressure, then the setpoint pressure can be controlled, but the opening position of the piston becomes dependent on fluid pressure, making it difficult to detect without additional measurements
Solution Approach 1:
The patent applies feedback by using the control device to monitor the actual opening position of the piston and compare it with the expected opening position based on the setpoint pressure. This feedback mechanism allows the system to detect calibration changes in the pressure sensor by identifying discrepancies between measured and expected values, thereby solving the detection difficulty.
3Adaptability or versatility
If the calibration of the pressure sensor is changed or deliberately adjusted for tuning purposes, then the pressure reading can be modified, but an incorrect assignment of pressure value to amplitude value occurs, affecting system accuracy
Solution Approach 1:
The patent applies self-service by enabling the system to automatically detect and identify calibration changes in the pressure sensor without requiring external calibration equipment or manual intervention. The control device performs the calibration check using existing system components, allowing the system to self-diagnose sensor calibration status and maintain measurement accuracy.
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 effectively identifies incorrect calibration of pressure sensors, ensuring accurate fluid pressure adjustment and preventing engine performance issues by reliably detecting changes in the opening position and fluid pressure, even at high pressures above 400 bar.
Implementation Method 1
The electromagnet to which current is applied magnetically attracts an armature which is connected to the inlet valve, so that said valve is carried along.
Implementation Method 2
Downstream of the outlet valve, there is a pressure sensor which generates a sensor signal which is intended to indicate the fluid pressure.
Implementation Method 3
by means of the control device (17), when the inlet valve (16) is closed, a measurement current (47) is applied to the electromagnet (18), and, while the piston (22) is again moved away from top dead center (31), on the basis of a predetermined change with respect to time (50) of the measurement current (47), an opening position (43) of the piston (22) is detected
Data Source
AI summary
Various embodiments include a method for checking a calibration of a pressure sensor comprising: moving a piston toward a TDC in successive cycles; while the piston moves toward TDC, closing an inlet valve thereby adjusting a setpoint value of a fluid pressure; measuring the fluid pressure with the pressure sensor arranged downstream of the outlet valve; applying a measurement current to the electromagnet when the inlet valve is closed; while the piston moves away from TDC, detecting an opening position of the inlet valve on the basis of a predetermined change with respect to time of the measurement current at which an opening movement of the inlet valve begins; over multiple pump cycles, changing the setpoint value of the fluid pressure by a predetermined difference; checking whether the change in opening position satisfies a predetermined correspondence criterion; and if the criterion is met, generating a fault signal.