Hybrid EV Catalyst Warm-Up Control During Engine Idle-Off
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Solution Overview
Problem
Existing hybrid electric vehicles struggle to perform rapid catalyst warm-up during engine idle-off conditions due to differences in control strategies between idle-on and idle-off states, which hinders effective exhaust gas treatment.
Innovation Solution
A hybrid electric vehicle system with a first electric motor connected to the engine's output shaft and a second motor for travel, utilizing a control device to manage engine and motor operations during idle-off, including feedback control of ignition timing and air amount to maintain stable catalyst warm-up, even when idling is not instructed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If rapid catalyst warm-up is performed during idle-off by controlling engine speed and torque, then catalyst temperature increases effectively, but control system complexity increases due to coordination of engine and first electric motor
Solution Approach 1:
The control system is segmented into distinct control modes: idle-on mode and idle-off mode. Each mode has predetermined control parameters for engine speed and torque. This segmentation allows the system to handle different operating conditions with pre-defined strategies, reducing the complexity of real-time decision-making while ensuring effective catalyst warm-up during idle-off
Solution Approach 2:
The system changes control parameters (engine speed and torque settings) based on the operating mode. During idle-off, specific predetermined parameters are applied to enable catalyst warm-up. This parameter-based approach allows the control system to adapt to different conditions without requiring complex algorithms, simply by switching between predefined parameter sets
2Measurement precision
If feedback control with proportional and integral terms is used for air amount and ignition timing, then control precision improves, but computational load on the control device increases
Solution Approach 1:
Feedback control is applied selectively rather than continuously across all operating conditions. The proportional and integral terms are used specifically for air amount and ignition timing control during catalyst warm-up operations. This partial application of feedback control provides sufficient precision where needed while avoiding unnecessary computational overhead during normal operation
Solution Approach 2:
The system implements feedback control mechanisms that monitor actual engine parameters and adjust control inputs accordingly. The proportional term responds to current deviations from target values, while the integral term accumulates past errors. This feedback structure improves control precision by continuously correcting deviations, while the mathematical simplicity of PID control keeps computational requirements manageable
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
Enables appropriate and stable rapid catalyst warm-up during idle-off by controlling engine speed and torque, reducing load on the control system and maintaining optimal exhaust gas treatment, while minimizing sudden changes in ignition timing.
Implementation Method 1
an exhaust gas control device provided with a catalyst that controls exhaust gas
Implementation Method 2
rapid catalyst warm-up in which fuel is injected in a compression stroke or an expansion stroke in the engine and the engine is operated with an ignition timing being retarded so as to warm up a catalyst
Data Source
AI summary
Hybrid electric vehicle includes an engine, a first electric motor, a second electric motor, an electric power storage device, and a control device. The control device is configured to control the engine and the first electric motor so that the engine is operated at a first predetermined engine speed while outputting a predetermined torque, and to control the second electric motor so that a driving force based on a required driving force is output, when the rapid catalyst warm-up is executed when the engine is idle off.