Coordinated Engine and SCR Control via Predictive Models
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Solution Overview
Problem
Current control strategies for internal combustion engines often fail to optimally coordinate engine and selective catalytic reduction (SCR) device operations, leading to suboptimal NOx emission reduction and fuel efficiency, particularly due to the differing time constants and dynamic interactions between the two systems.
Innovation Solution
The implementation of a coordinated control system using predictive model controllers to manage both the engine and SCR device, where models of the engine and after-treatment subsystems are synthesized to create multivariable controllers that dynamically adjust engine actuators and urea solution dosing to maximize NOx reduction and fuel efficiency, employing a cascaded or hierarchical control structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If independent control strategies are used for engine and SCR device, then control system complexity is reduced, but NOx emission reduction performance becomes suboptimal
Solution Approach 1:
The patent combines the engine control system and SCR device control system into a unified coordinated control system. The controller receives inputs from both subsystems and generates coordinated control signals that optimize overall NOx reduction performance, merging previously independent control functions into an integrated system that accounts for interactions between engine operation and SCR treatment.
Solution Approach 2:
The coordinated control system performs multiple functions simultaneously: it manages engine operation parameters, controls SCR urea dosing, optimizes exhaust gas recirculation, and coordinates temperature management across both subsystems. This multi-functional controller replaces multiple separate control strategies with a single universal control architecture.
2Object-generated harmful factors
If engine control prioritizes NOx reduction through massive exhaust gas recirculation, then engine-out NOx is reduced, but fuel efficiency deteriorates
Solution Approach 1:
The coordinated control system acts as an intermediary that balances the trade-off between NOx reduction and fuel efficiency. Rather than relying solely on massive EGR for NOx control, the system uses the SCR device as an intermediary treatment mechanism that can handle NOx conversion more efficiently, allowing the engine to operate at optimal fuel efficiency while still achieving stringent NOx emission targets through the combined engine-SCR system.
3Ease of operation
If SCR device is relied upon to reduce NOx emissions, then engine control can be simplified, but coordinated optimization of fuel efficiency and NOx reduction is lost
Solution Approach 1:
The coordinated control system dynamically adjusts the division of labor between engine control and SCR control based on operating conditions. The control strategy adapts in real-time, optimizing the balance between engine-out NOx reduction and SCR-based NOx conversion to maximize overall system efficiency and fuel economy across different engine loads and operating scenarios.
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 effectively reduces NOx emissions to meet stringent regulations while improving vehicle fuel efficiency by optimizing the interaction between engine and SCR device operations, ensuring stable and efficient performance.
Implementation Method 1
Urea solution may be inserted into the exhaust emissions, which is decomposed to ammonia to become a reduction agent for reduction of NOx in the emissions
Implementation Method 2
The exhaust after-treatment device may use selective catalytic reduction to remove certain emissions from the exhaust of the engine
Data Source
AI summary
A system for reducing environmentally harmful emissions from an internal combustion engine. The system may incorporate an exhaust after-treatment device. The exhaust after-treatment device may use selective catalytic reduction to remove certain emissions from the exhaust of the engine. Urea solution may be inserted into the exhaust emissions, which is decomposed to ammonia to become a reduction agent for reduction of NOx in the emissions. The engine may be managed by a controller and the exhaust after-treatment device may be managed by another controller. These controllers may be cascaded, or be managed by a third controller that provides hierarchical or coordinated control of engine performance and emissions reduction. The engine and the exhaust after-treatment device may be modeled to aid in designing and building a system for coordinated control of an actual engine and a selective catalytic reduction after-treatment device. The controllers may be predictive model controllers.