Fuel Pressure Sensor Drift Detection and Control
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Solution Overview
Problem
Engine stalls occur due to drift in the output signal of high-pressure fuel pressure sensors, leading to inaccurate fuel injection and unstable engine RPM, as the sensor's sensitivity changes over time or temperature, causing excessive or insufficient fuel injection.
Innovation Solution
A method and apparatus that determine if a signal drift has occurred by comparing target and measured pressure values, and if so, perform fuel pressure control by replacing the high-pressure fuel pressure value with a predetermined value or using low-pressure fuel pressure at the upstream side of the high-pressure fuel pump, thereby preventing engine stall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the high-pressure fuel pressure sensor is used to measure fuel pressure for fuel injection control, then the fuel injection amount can be precisely controlled, but the sensor drift causes measurement errors leading to engine stall
Solution Approach 1:
The patent introduces a drift detection mechanism as an intermediary between the pressure sensor and the fuel injection control system. This intermediary detects sensor drift conditions and triggers a switching mechanism that bypasses the unreliable sensor readings, thereby protecting the control system from measurement errors while preserving the benefits of sensor-based control during normal operation
Solution Approach 2:
The system dynamically switches between two operational modes: normal sensor-based pressure control and drift-compensated control using alternative pressure sources. The switching is triggered by drift detection algorithms that monitor sensor output plausibility, allowing the system to adapt its measurement strategy in real-time based on sensor reliability
2Speed
If the sensor output signal is used directly for fuel amount control, then the response is fast and accurate, but sensor drift causes instantaneous pressure changes leading to unstable engine RPM
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors the pressure sensor output for drift conditions and compares it against expected pressure ranges. When drift is detected, the feedback loop switches to using alternative pressure measurements from upstream sensors, maintaining closed-loop control stability while preventing the propagation of erroneous sensor readings to the fuel injection actuator
3Reliability
If drift compensation is implemented by replacing pressure values, then engine stall is prevented, but the control system complexity increases
Solution Approach 1:
The system performs preliminary drift detection and validation checks on sensor readings before using them for fuel injection control. By proactively identifying drift conditions and switching to alternative pressure sources in advance, the system prevents engine stall without requiring complex real-time compensation algorithms during critical operations
Solution Approach 2:
The patent changes the operational parameter source from the potentially drifted high-pressure sensor to alternative pressure measurements from upstream low-pressure sensors or pre-stored pressure maps. This parameter substitution approach maintains control functionality while avoiding the complexity of real-time drift correction calculations
Data Source
AI summary
A method of preventing an engine stall of a vehicle having a fuel injection device for pressurizing fuel stored in a fuel tank by a high-pressure fuel pump to transmit the fuel to a common rail, and injecting the fuel temporarily stored in the common rail into an engine through an injector may include steps of determining whether or not a drift occurs in an output signal of a high-pressure fuel pressure sensor for measuring fuel pressure at a downstream side of the high-pressure fuel pump, and performing a fuel pressure control by replacing a high-pressure fuel pressure value with a predetermined pressure value based on the output signal of the high-pressure fuel pressure sensor.