Kalman Filter Cylinder Temperature Estimation
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Solution Overview
Problem
Current control systems for internal combustion engines face limitations due to indirect temperature measurements, as coolant temperature sensors do not accurately represent the thermal conditions within the engine cylinders, which are crucial for optimal combustion control.
Innovation Solution
A system and method that utilize a sensor to monitor coolant temperature, determine wall temperature, and correct predicted thermal states using a Kalman filter approach, accounting for noise covariance and sensor reliability, to enhance thermal management and control of internal combustion engines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If coolant temperature sensors are used to monitor thermal conditions, then measurement cost and complexity are reduced, but measurement precision and reliability of cylinder temperature data deteriorate
Solution Approach 1:
The patent uses coolant temperature as an intermediary measurement to infer cylinder temperature indirectly. Since directly measuring cylinder temperature is impractical, the system uses the coolant temperature (which is easier to measure) combined with thermal models and noise covariance analysis to estimate the cylinder temperature, thus resolving the contradiction between measurement ease and accuracy
Solution Approach 2:
The patent replaces direct physical temperature sensing in the cylinder with a model-based estimation system. Instead of using physical sensors inside the cylinder, it uses a thermal model processed by a controller that incorporates noise covariance to substitute direct mechanical measurement with computational estimation
2Measurement precision
If direct cylinder temperature measurement is implemented, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The patent employs coolant temperature as a mediator variable that can be measured easily with simple sensors. This intermediary measurement, when processed through thermal models and noise covariance analysis, provides accurate cylinder temperature estimation without requiring complex direct measurement systems inside the cylinder
Solution Approach 2:
The patent creates a virtual copy of the cylinder temperature measurement through model-based estimation. Instead of physically placing sensors in the cylinder, it creates a computational replica of the temperature data using thermal models that replicate the thermal behavior, achieving accurate measurement without physical intrusion
3Ease of operation
If coolant temperature is used to control combustion, then ease of operation is improved, but control reliability deteriorates due to indirect temperature indication
Solution Approach 1:
The patent implements a feedback mechanism where the controller processes thermal models and compares predicted temperatures with actual coolant temperature measurements. The noise covariance analysis provides feedback on measurement reliability, allowing the system to adjust control decisions based on the confidence level of temperature data, thus improving combustion control reliability while maintaining ease of operation
Solution Approach 2:
The patent replaces direct mechanical temperature sensing in the combustion chamber with a computational estimation system that uses thermal models. This substitution maintains ease of operation by using the same simple coolant temperature sensors but improves reliability through model-based correction and noise covariance analysis
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 provides robust and accurate temperature estimations, improving engine performance and fuel efficiency by directly addressing the limitations of indirect temperature measurements and sensor reliability, especially during dynamic combustion cycles.
Implementation Method 1
A sensor is disposed to monitor a current state of a parameter of the thermal system
Implementation Method 2
The controller corrects the next-step state based, at least in-part, on the noise covariance resulting in a corrected next-step state
Data Source
AI summary
Systems and methods are provided for determining a temperature of a thermal system that includes fluid conduits. A sensor monitors a current state of the temperature. A controller receives a signal from the sensor that is representative of the current state; determines a flow in the fluid conduits; determines a noise covariance of the thermal system; processes a thermal model of the thermal system; predicts a next-step state of the parameter at a time after the current state; and corrects the next-step state based, at least in-part, on the noise covariance resulting in a corrected next-step state.