Model Predictive Control for Catalyst Light-Off Transitions
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Solution Overview
Problem
Traditional engine control systems fail to accurately control engine output torque and do not provide rapid responses to control signals, leading to inefficiencies in catalyst light-off periods, which affects emissions reduction during engine startup.
Innovation Solution
A system utilizing a catalyst light-off module, setpoint module, and model predictive control (MPC) module to optimize catalyst temperature increase by adjusting engine parameters such as throttle, spark timing, and exhaust gas recirculation, while minimizing emissions during the light-off period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional engine control systems are used to control engine output torque, then the control system is simple, but the torque control accuracy is insufficient and response speed is slow
Solution Approach 1:
The patent implements dynamic model predictive control that continuously updates control targets based on real-time engine operating conditions and predicted future states. The control system dynamically adjusts torque targets for multiple actuators (throttle, spark timing, EGR valve) to achieve accurate torque control while maintaining adaptability to changing conditions, thereby improving torque control accuracy without requiring overly complex static control structures.
Solution Approach 2:
The patent uses predictive control to calculate future torque targets based on predicted engine states and operating conditions before they actually occur. By anticipating future requirements and pre-calculating optimal control targets, the system achieves rapid response to control signals and accurate torque control, eliminating the need for complex real-time iterative control while improving both accuracy and response speed.
2Object-generated harmful factors
If catalyst light-off period is extended to increase catalyst temperature, then emissions reduction is improved, but the time required for catalyst activation increases
Solution Approach 1:
The patent dynamically changes multiple engine operating parameters (throttle opening, spark timing, EGR rate, fuel injection timing) during the catalyst light-off period to optimize exhaust temperature and composition. By coordinating changes in these parameters, the system achieves rapid catalyst activation and effective emissions reduction simultaneously, rather than extending the light-off period.
Solution Approach 2:
The predictive control system pre-calculates optimal control targets for the catalyst light-off period based on predicted engine operating conditions and catalyst temperature trajectories. This allows the system to immediately implement optimized control actions when cold start occurs, achieving rapid catalyst activation and emissions control without time loss.
3Measurement precision
If multiple actuators are coordinated for torque control, then torque control accuracy is improved, but the complexity of coordinating various devices increases
Solution Approach 1:
The patent implements dynamic coordination of multiple actuators (throttle valve, spark timing, EGR valve) through model predictive control. The system continuously calculates optimal torque targets for each actuator based on real-time operating conditions and predicted future states, enabling accurate torque control through coordinated actuator operation without requiring complex manual tuning or iterative control algorithms.
Solution Approach 2:
The predictive control system serves multiple functions simultaneously: it coordinates multiple actuators for torque control, optimizes catalyst light-off, and manages emissions control. By using a single unified predictive control framework to handle multiple control objectives and actuator coordination, the system achieves accurate torque control without proportionally increasing control system 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
The system effectively reduces emissions by optimizing the catalyst light-off period and minimizing engine emissions during startup, improving the engine's efficiency and emissions control.
Implementation Method 1
The catalyst reacts with one or more components of exhaust flowing through the catalyst in order to reduce emissions in the exhaust
Implementation Method 2
Internal combustion engines combust an air and fuel mixture within cylinders to drive pistons, which produces drive torque
Data Source
AI summary
A system includes a catalyst light-off module that selectively generates a first signal based on an engine coolant temperature and an estimated exhaust enthalpy, a setpoint module that selectively initiates a catalyst light-off period in response to receiving the first signal and that generates a desired exhaust enthalpy, and a first model predictive control (MPC) module that generates predicted parameters based on a model of an engine and a set of possible target values, generates a cost for the set of possible target values based on the predicted parameters and the desired exhaust enthalpy, and selects the set of possible target values from multiple sets of possible target values based on the cost. The system also includes an engine actuator module that adjusts an actuator of the engine based on at least one of the target values.