Fuel Pressure Sensor Error Detection via Pump Pulse Flattening
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Solution Overview
Problem
Existing methods for diagnosing in-range errors in pressure sensors downstream of fuel lift pumps in internal combustion engines are inadequate, particularly in closed-loop control systems, as they fail to detect sensor degradation within the normal operating range, leading to incorrect fuel pressure adjustments and potential engine operation issues.
Innovation Solution
A method that adjusts the voltage applied to the fuel lift pump based on the output signal of the pressure sensor during pulsed mode operation and monitors for flattening, switching from closed-loop to open-loop control upon error detection, while dynamically learning setpoint pressure and fuel vapor pressure to improve accuracy and robustness of fuel system control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If closed-loop control is used with pressure sensor feedback, then fuel pressure control accuracy is improved, but in-range sensor errors cannot be detected leading to incorrect adjustments
Solution Approach 1:
The system performs preliminary actions by monitoring pressure trends and detecting sensor degradation before it causes incorrect fuel pressure adjustments. The controller continuously analyzes pressure data during pulsed pump operation to identify flattening patterns, enabling early detection of in-range sensor errors before they compromise closed-loop control accuracy.
Solution Approach 2:
The system uses feedback by continuously monitoring the pressure sensor output during pulsed pump operation and analyzing trends in the pressure data. The controller detects flattening in pressure trends, which indicates sensor degradation, and uses this feedback information to switch from closed-loop to open-loop control, preventing incorrect fuel pressure adjustments.
2Use of energy by moving object
If pulsed pump operation is used, then energy efficiency and pump durability are improved, but sensor degradation is harder to detect
Solution Approach 1:
The system exploits the periodic nature of pulsed pump operation to detect sensor degradation. By monitoring pressure fluctuations during each pulse cycle and identifying flattening patterns in the pressure waveform, the system can detect sensor degradation that would be difficult to identify in continuous operation. The periodic pressure changes during pulsed operation create a characteristic pattern that reveals sensor issues.
Solution Approach 2:
The system uses dynamics by analyzing the temporal behavior of pressure changes during pulsed pump operation. The controller monitors how pressure evolves during each pulse cycle and detects deviations from expected dynamic patterns, such as flattening of pressure curves, which indicate sensor degradation. This dynamic analysis enables detection of sensor issues that would be invisible in static measurements.
3Productivity
If voltage level is adjusted for constant delivery pressure, then fuel flow demand response is improved, but sensor errors lead to incorrect voltage adjustments
Solution Approach 1:
The system performs preliminary detection of sensor degradation before making voltage adjustments. By monitoring pressure trends during pulsed operation, the controller identifies sensor errors early and prevents incorrect voltage adjustments that would result from faulty sensor readings, thereby maintaining accurate fuel flow control despite the presence of degraded sensors.
Data Source
AI summary
Methods and systems are provided for diagnosing an in-range error of a pressure sensor arranged downstream of a lift pump in a fuel system of a vehicle. In one example, a method may include performing feedback control of the lift pump based on output of the pressure sensor, monitoring the pressure sensor output for flattening during the application of the voltage pulses, and adjusting operation of the fuel system depending on whether the pressure sensor output flattens for at least a threshold duration, which is indicative of an in-range error. The method may further include dynamically learning a setpoint pressure of a pressure relief valve of the fuel system and a fuel vapor pressure within the fuel system by monitoring pressure sensor output while adjusting the duty cycle of voltage pulses applied to the lift pump.