Internal Combustion Engine Pressure Sensor Diagnostics Using Compressor Speed
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Solution Overview
Problem
Existing internal combustion engine (ICE) systems face challenges in accurately diagnosing pressure sensors in exhaust gas conduits, particularly when equipped with controllable backpressure valves, due to dynamic exhaust gas flow control and harsh operating conditions, leading to sensor malfunctions and inaccurate diagnostics during active operations like engine braking or heat modes.
Innovation Solution
A system and method using compressor speed and pressure ratio to determine exhaust gas pressure downstream a controllable backpressure valve, allowing for diagnosing pressure sensors without needing feedback on the valve's position, and optionally using two pressure sensors for enhanced accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure sensor is installed in the exhaust gas conduit downstream of the controllable backpressure valve to monitor exhaust pressure, then the control of the ICE system and exhaust aftertreatment can be improved, but the sensor may malfunction or provide inaccurate readings under harsh operating conditions such as engine braking or heat modes
Solution Approach 1:
The control system proactively determines the operational status of the pressure sensor by comparing measured exhaust pressure with calculated reference pressure before these inaccurate readings can cause harmful effects. This preliminary detection allows the system to identify sensor malfunctions during engine braking or heat modes before they lead to improper control decisions
Solution Approach 2:
The system implements a feedback mechanism where the control system continuously monitors the pressure sensor readings, compares them against calculated reference values based on compressor speed and pressure ratio, and uses this feedback to determine sensor operational status. This closed-loop approach enables real-time detection of sensor degradation or malfunction under harsh conditions
2Measurement precision
If traditional diagnostic methods are used for pressure sensors, then the system structure remains simple, but accurate diagnosis of sensor status during active operations like engine braking or heat modes cannot be achieved
Solution Approach 1:
The system uses compressor speed and pressure ratio as intermediary parameters to calculate a reference exhaust pressure that serves as a mediator for diagnosing the pressure sensor status. Instead of directly monitoring the sensor under all conditions, the system uses these intermediary measurements to indirectly assess sensor accuracy by comparing against the calculated reference value
Solution Approach 2:
The diagnostic system leverages existing operational parameters (compressor speed, pressure ratio) that are already being measured for normal ICE system control. By using these self-generated data sources to calculate reference pressure and diagnose sensor status, the system achieves accurate diagnostics without requiring additional dedicated diagnostic sensors or complex external testing equipment
Data Source
AI summary
The present disclosure relates to an internal combustion engine (ICE) system comprising: an internal combustion engine; a turbocharger arrangement, the turbocharger arrangement having a turbine arranged in an exhaust gas conduit, the exhaust gas conduit extending between the internal combustion engine and the turbine, and further a compressor disposed in an inlet manifold, the inlet manifold extending between the compressor and the internal combustion engine; a controllable backpressure valve being located in the exhaust gas conduit, the controllable backpressure valve being configured to control the pressure within the exhaust gas conduit; a pressure sensor disposed in the exhaust gas conduit, and further in-between the controllable backpressure valve and the turbine, the pressure sensor being configured to measure an exhaust gas pressure downstream the controllable backpressure valve; a speed sensor configured to measure a compressor speed; and a control system for determining an operational status of the pressure sensor.