EGR Valve Flow Estimation Using Sensor Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The accuracy of exhaust gas recirculation (EGR) estimates using existing sensors, such as intake oxygen sensors and differential pressure sensors, is reduced under certain engine operating conditions, leading to inconsistent engine control.
Innovation Solution
A method that adjusts engine operation based on final gas flow parameter estimates from both a differential pressure sensor and an intake oxygen sensor, considering the accuracy values of each sensor under different engine conditions to improve the accuracy of EGR flow estimates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single sensor (intake oxygen sensor or differential pressure sensor) is used to estimate EGR flow, then the system is simple, but the measurement precision deteriorates under certain engine operating conditions
Solution Approach 1:
The patent combines multiple sensors (intake oxygen sensor and differential pressure sensor) to estimate EGR flow. The controller receives signals from both sensors and integrates their outputs to produce a final EGR flow estimate, thereby improving measurement precision while managing system complexity through coordinated use of existing components
Solution Approach 2:
The patent introduces an intermediary processing layer (the controller) that receives raw signals from multiple sensors, evaluates their accuracy based on operating conditions, and synthesizes a final EGR flow estimate. This intermediary process resolves the contradiction by intelligently combining sensor data rather than simply adding hardware complexity
2Device complexity
If the intake oxygen sensor is used to estimate EGR flow, then the system is simple, but the measurement precision deteriorates when purge and PCV gasses are flowing through the intake system
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously monitors operating conditions (detecting when purge and PCV gasses are present) and adjusts the EGR flow estimation strategy accordingly. When purge/PCV conditions are detected, the system relies more heavily on the differential pressure sensor, which remains accurate under these conditions, thereby maintaining measurement precision
Solution Approach 2:
The patent dynamically adjusts which sensor is prioritized for EGR flow estimation based on real-time operating conditions. The system transitions between relying on the intake oxygen sensor (during normal operation) and the differential pressure sensor (during purge/PCV operation), optimizing measurement precision without requiring a fixed complex sensor configuration
3Measurement precision
If the differential pressure sensor is used to estimate EGR flow, then the measurement precision is maintained during purge/PCV operation, but the device complexity increases
Solution Approach 1:
The patent makes the sensor system universal by having both sensors capable of contributing to EGR flow estimation under different conditions. The differential pressure sensor serves as a reliable backup and primary sensor during purge/PCV operation, while the intake oxygen sensor handles normal conditions, optimizing the use of both components across the full range of operating conditions
Solution Approach 2:
The patent changes the weighting parameters of sensor contributions based on operating conditions. During purge/PCV operation, the system increases the weight of the differential pressure sensor signal and decreases the weight of the intake oxygen sensor signal, dynamically adjusting the estimation parameters to maintain precision without permanently increasing hardware complexity
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 approach results in a more accurate EGR flow estimate, enhancing engine control by incorporating the outputs from both sensors based on their respective accuracy values, thereby maintaining precision across a wider range of operating conditions.
Implementation Method 1
differential pressure (DP) sensor positioned around an EGR valve for estimating EGR flow based on a pressure difference across the EGR valve
Implementation Method 2
intake gas constituent sensor, such as an oxygen sensor, which may be employed during non-EGR conditions to determine the oxygen content of fresh intake air
Data Source
AI summary
Methods and systems are provided for adjusting an exhaust gas recirculation (EGR) valve based on a final EGR estimate. In one example, a method may include adjusting the EGR valve based on a final EGR flow estimate, the final EGR flow estimate based on a first EGR flow estimated with a differential pressure sensor across the EGR valve, a second EGR flow estimated with an intake oxygen sensor, and accuracy values of each of the first and second EGR flows. The accuracy value may be based on engine operating conditions during estimation of the first and second EGR flows.