Fuel Pressure Sensor Error Detection via Voltage Pulse Flattening
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for diagnosing in-range errors in pressure sensors downstream of fuel lift pumps in internal combustion engines are inadequate, as they fail to detect errors within the normal operating range, leading to potential engine operation issues and driver dissatisfaction.
Innovation Solution
A method that adjusts the voltage level 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.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If closed-loop control is used with pressure sensor feedback, then fuel system efficiency is improved, but in-range sensor errors go undetected causing incorrect pump control adjustments
Solution Approach 1:
The system performs preliminary actions by monitoring pressure sensor output for flattening conditions before making control adjustments. The controller detects when the pressure sensor output fails to change despite voltage changes to the lift pump, indicating an in-range error, and takes corrective action by switching to open-loop control or adjusting pump operation accordingly.
Solution Approach 2:
The system uses feedback by continuously monitoring the pressure sensor output signal in response to voltage changes applied to the lift pump. The controller observes whether the pressure sensor output flattens (fails to change) when voltage is adjusted, and uses this feedback information to detect in-range errors and modify control strategy.
2Loss of energy
If pulsed pump operation is used, then energy efficiency and pump durability are improved, but in-range sensor errors are more difficult to detect
Solution Approach 1:
The system applies periodic voltage pulses to the lift pump and periodically monitors the pressure sensor output. By applying voltage at different levels during pulsed operation and observing whether the pressure sensor output flattens between pulses, the system can detect in-range errors while maintaining the energy efficiency benefits of pulsed operation.
Solution Approach 2:
The controller applies partial voltage changes to the lift pump during pulsed operation to test sensor response. By making incremental voltage adjustments and monitoring for flattening conditions, the system can detect sensor errors without requiring full voltage changes, thus maintaining energy efficiency while enabling error detection.
3Productivity
If voltage level adjustments are made to maintain constant delivery pressure, then fuel flow demand response is improved, but sensor degradation shifts pressure readings causing operation degradation
Solution Approach 1:
The system performs preliminary monitoring of pressure sensor output before making voltage adjustments to maintain constant delivery pressure. By detecting flattening conditions in advance, the system can identify sensor degradation and switch to open-loop control or alternative strategies before pressure control accuracy is compromised.
Solution Approach 2:
The system uses feedback by continuously monitoring pressure sensor output during voltage adjustments. When the pressure sensor output flattens in response to voltage changes, the controller detects this feedback signal and adjusts control strategy to maintain reliable operation despite sensor degradation.
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.