Turbine Outlet Temperature Control via Virtual Sensors
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Solution Overview
Problem
Diesel engines face a tradeoff between minimizing NOx emissions and maintaining engine efficiency, with existing EGR systems often resulting in a loss of efficiency and requiring accurate real-time control of air, fuel, and exhaust gas proportions to manage turbine outlet temperatures effectively.
Innovation Solution
A method and system that utilize virtual sensors to control turbine outlet temperatures by determining acceptable charge flows, incorporating a turbine outlet temperature virtual sensor and a turbine inlet temperature virtual sensor to modulate exhaust temperatures, allowing for precise control of engine operation to achieve desired exhaust temperatures and reduce emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If EGR systems are used to reduce NOx emissions by introducing exhaust gases into the fresh air stream, then NOx production is reduced, but engine efficiency is lost
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the EGR valve position and intake manifold absolute pressure (IMAP) based on real-time sensor data. The control system modifies the proportion of exhaust gas recirculated and the pressure differential across the turbocharger to optimize the balance between NOx reduction and engine efficiency. This involves continuously varying operational parameters such as EGR flow rate, charge air pressure, and temperature to achieve optimal emissions control without excessive efficiency penalty.
Solution Approach 2:
The patent implements feedback control by using sensor data from the exhaust gas temperature sensor, IMAP sensor, and other engine parameters to continuously monitor and adjust EGR valve position. The control algorithm processes real-time feedback signals to determine the optimal EGR rate that achieves NOx reduction targets while maintaining engine efficiency. The system adjusts the EGR valve based on feedback from temperature and pressure sensors to dynamically optimize the tradeoff between emissions and efficiency under varying operating conditions.
2Quantity of substance
If turbocharger machinery is used to increase mass of fresh air flow, then oxygen concentration in combustion chamber increases, but peak combustion temperatures increase leading to higher NOx production
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the EGR valve position and intake manifold absolute pressure (IMAP) based on real-time sensor data. The control system modifies the proportion of exhaust gas recirculated and the pressure differential across the turbocharger to optimize the balance between NOx reduction and engine efficiency. This involves continuously varying operational parameters such as EGR flow rate, charge air pressure, and temperature to achieve optimal emissions control without excessive efficiency penalty.
Solution Approach 2:
The patent uses exhaust gases as an intermediary substance to reduce NOx formation. By introducing exhaust gases (which contain nitrogen and carbon dioxide) into the fresh air stream through the EGR system, the oxygen concentration is diluted, which prevents excessive peak combustion temperatures and subsequent NOx formation. The exhaust gases act as a mediator that modulates the combustion process to achieve lower emissions while maintaining acceptable engine performance.
3Measurement precision
If accurate real-time control of air, fuel and exhaust gas proportions is implemented, then turbine outlet temperatures can be controlled to meet emission standards, but control system complexity increases
Solution Approach 1:
The patent implements feedback control by using sensor data from the exhaust gas temperature sensor, IMAP sensor, and other engine parameters to continuously monitor and adjust EGR valve position. The control algorithm processes real-time feedback signals to determine the optimal EGR rate that achieves NOx reduction targets while maintaining engine efficiency. The system adjusts the EGR valve based on feedback from temperature and pressure sensors to dynamically optimize the tradeoff between emissions and efficiency under varying operating conditions.
Solution Approach 2:
The control system performs self-service by automatically adjusting EGR valve position and IMAP based on sensor feedback without requiring manual intervention. The system uses its own sensor data to autonomously optimize emissions control and engine performance, reducing the need for complex external control mechanisms. The microprocessor-based control system self-regulates by processing sensor signals and automatically modifying operational parameters to achieve optimal emissions management.
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 enables efficient management of turbine outlet temperatures, facilitating the regeneration of aftertreatment systems and meeting stringent emission standards while minimizing NOx production, thereby optimizing engine performance and reducing emissions.
Implementation Method 1
Control strategies to utilize the charge flow as a lever to control turbine outlet temperature are disclosed. These strategies utilize the inversion of the cylinder outlet temperature virtual sensor as well as a new turbine outlet temperature virtual sensor to determine the charge flow required to achieve the desired turbine outlet temperature given the current turbine inlet and outlet pressure, SOI, charge pressure, charge temperature, fueling, and engine speed.
Implementation Method 2
One known method for achieving the foregoing result is through the use of a so-called Exhaust Gas Recirculation (EGR) system operable to controllably introduce (i.e., recirculate) exhaust gas from the exhaust manifold into the fresh air stream flowing to the intake manifold to controllably introducing exhaust gas to the intake manifold.
Implementation Method 3
By thusly reducing the oxygen concentration of the resulting charge to be combusted, the fuel bums slower and peak combustion temperatures are accordingly reduced, thereby lowering the production of NOx.
Implementation Method 4
When combustion occurs in an environment with excess oxygen, peak combustion temperatures increase which leads to the formation of unwanted emissions, such as oxides of nitrogen (NOx).
Data Source
AI summary
A method and system for controlling an exhaust temperature for an internal combustion engine is disclosed. The method and system include determining a range of acceptable charge flows within the internal combustion engine to meet a desired exhaust temperature. The method and system further include controlling the charge flows to fall within the range. Control strategies to utilize the charge flow as a lever to control turbine outlet temperature are disclosed. These strategies utilize the inversion of the cylinder outlet temperature virtual sensor as well as a new turbine outlet temperature virtual sensor to determine the charge flow required to achieve the desired turbine outlet temperature given the current turbine inlet and outlet pressure, SOI, charge pressure, charge temperature, fueling, and engine speed.