Multi-mode Powertrain Catalyst Light-off Control
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Solution Overview
Problem
Multi-mode powertrain systems face challenges in efficiently managing the light-off of catalytic devices in exhaust aftertreatment systems, particularly in achieving the catalyst light-off temperature for effective emissions reduction, as existing systems lack optimal control strategies to transition between engine states and manage torque distribution effectively.
Innovation Solution
A multi-mode powertrain system with a power-split configuration and a state machine control scheme that identifies permitted transition paths between engine states (default, pre-light-off, and light-off states) to manage engine operation based on output torque requests and catalytic device temperature, ensuring efficient catalyst light-off by controlling engine modes and torque distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the engine operates in default mode without specific light-off control, then the system structure remains simple, but the catalyst light-off temperature cannot be achieved efficiently
Solution Approach 1:
The system dynamically transitions between different engine operating modes (default mode, first light-off mode, second light-off mode) based on catalyst temperature and vehicle operating conditions. This dynamic adaptation allows the system to achieve catalyst light-off temperature efficiently while managing control complexity through structured mode transitions rather than continuous complex control algorithms.
Solution Approach 2:
The control system changes key operating parameters (engine load, speed, air-fuel ratio) when transitioning between operating modes to achieve catalyst light-off. By systematically adjusting these parameters in defined mode transitions, the system achieves the required temperature increase without requiring overly complex control mechanisms.
2Object-generated harmful factors
If the engine transitions through multiple states to achieve catalyst light-off, then emissions reduction is improved, but the control system complexity increases
Solution Approach 1:
The control strategy segments the catalyst light-off process into distinct operating modes (default mode, first light-off mode, second light-off mode) with specific transition conditions. This segmentation simplifies the control logic by breaking down the complex emissions reduction task into manageable, predefined stages, each with clear entry and exit criteria.
Solution Approach 2:
The system uses catalyst temperature feedback to determine mode transitions and adjust operating parameters. The controller continuously monitors catalyst temperature and uses this feedback to decide when to transition between operating modes, ensuring emissions reduction is achieved while maintaining manageable control complexity through responsive feedback-based decision making.
3Productivity
If the engine operates in light-off modes with optimized parameters, then catalyst light-off efficiency is improved, but the ease of operation decreases
Solution Approach 1:
The system automatically manages mode transitions based on predefined conditions (catalyst temperature, vehicle speed, load requirements) without requiring manual intervention. The controller self-adjusts operating parameters and transitions between modes autonomously, maintaining high light-off efficiency while preserving ease of operation through automated decision-making rather than manual control 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 transitions engine states to achieve catalyst light-off, improving emissions reduction by optimizing engine operation and torque management, thereby enhancing the efficiency of the catalytic device's temperature management and emissions treatment.
Implementation Method 1
Exhaust aftertreatment devices include catalysts that are configured to oxidize, reduce, reform, filter, and otherwise transform exhaust gas constituents to elemental nitrogen, carbon, CO2, H2O, and other molecules in the presence of catalysts and other constituents
Implementation Method 2
Exhaust aftertreatment devices include catalysts that are configured to oxidize, reduce, reform, filter, and otherwise transform exhaust gas constituents
Implementation Method 3
Exhaust aftertreatment devices include catalysts that are configured to oxidize, reduce, reform, filter, and otherwise transform exhaust gas constituents
Implementation Method 4
The catalyst light-off temperature correlates to operation of the catalyst which is exothermic in nature, and is thus self-sustaining without need for additional engine control operation to introduce heat into the catalyst
Data Source
AI summary
A multi-mode powertrain system employing a power-split configuration to transfer torque to a driveline includes an internal combustion engine fluidly coupled to an exhaust aftertreatment system having a catalytic device. A method for controlling the multi-mode powertrain system includes identifying permitted transition paths between a plurality of engine states. The plurality of engine states includes a default state, a pre-light-off state, a light-off state, and a post-light-off state. A preferred one of the plurality of engine states is selected in response to an output torque request and an operating temperature of the catalytic device. Engine operation is transitioned to the preferred one of the plurality of engine states via the permitted transition paths, and the engine is operated in the preferred one of the plurality of engine states.