Engine Exhaust Temperature Estimator Using Observer Error Correction
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Solution Overview
Problem
Existing temperature estimation methods for internal combustion engine exhaust temperatures are inadequate due to long response times of temperature sensors, which fail to provide precise and rapid data necessary for effective engine control and component protection.
Innovation Solution
A temperature estimator is introduced, comprising a module for receiving sensor measurements and external data, with an observer capable of determining estimated temperatures and adjusting for measurement errors, incorporating a dynamic compensation gain to improve precision and response time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is used to measure exhaust temperature, then temperature data can be obtained, but the response time is too long (several seconds to reach 60% of loop deviation)
Solution Approach 1:
The patent introduces an observer as an intermediary computational system that processes sensor measurements and fluid dynamics models to generate corrected temperature estimates. This observer acts as a mediator between the slow physical sensor and the fast control system, providing rapid temperature estimates without requiring additional physical sensors.
Solution Approach 2:
The patent replaces the purely mechanical/physical temperature sensing approach with a computational approach using an observer algorithm. Instead of relying solely on physical sensor response, the system uses mathematical models and computational correction to accelerate temperature estimation, substituting mechanical response limitations with computational processing.
2Loss of time
If a linear model of sensor response is used to estimate temperature, then response time is improved, but model instability occurs and coupling with other models is prevented
Solution Approach 1:
The patent creates a composite estimation model that combines multiple components: sensor measurements, fluid dynamics models, and correction algorithms. This composite approach integrates different modeling techniques to achieve both fast response and stability, overcoming the limitations of simple linear models while maintaining coupling capability with other system models.
Solution Approach 2:
The observer implements feedback mechanisms where temperature estimates are continuously refined based on sensor measurements and model predictions. This feedback loop ensures model stability by correcting deviations and maintaining consistency with actual system behavior, preventing the instability issues seen in open-loop linear models.
3Loss of information
If the sensor response is considered as input for temperature estimation, then temperature can be estimated, but the measurement error is not corrected
Solution Approach 1:
The observer serves as an intermediary that processes raw sensor inputs and applies correction algorithms to eliminate measurement errors. This intermediary layer transforms inaccurate sensor data into accurate temperature estimates by compensating for sensor dynamics and fluid effects.
Solution Approach 2:
The system changes the parameters used for temperature estimation by incorporating fluid dynamics parameters (flow rate, pressure, temperature gradients) alongside sensor measurements. This parameter transformation allows the system to correct measurement errors by using alternative physical relationships to infer accurate temperature values.
Data Source
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AI summary
The temperature estimator (32) is intended to be incorporated into a motor vehicle internal combustion engine. It comprises a first module (36) for receiving a parameter measured by a sensor located in a fluid flow passing through the internal combustion engine (2), a second module (38) for receiving an external data item, and a module (44) for determining a temperature of the fluid flow. The determination module (44) comprises an observer capable of determining an estimated temperature of the fluid flow and an estimated parameter linked to the sensor, the observer being configured to determine the estimated temperature of the fluid flow taking account of a measurement error in the estimated parameter.