Series Hybrid Engine Control for Catalyst Temperature Limits
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Solution Overview
Problem
Series hybrid vehicles face the challenge of maintaining catalyst temperature control to prevent deactivation due to high exhaust gas temperatures, especially when a small engine is operated under high load conditions to generate electric power.
Innovation Solution
A control device and method that monitor catalyst temperature and adjust the engine operating point to reduce exhaust gas temperature while maintaining power generation, by shifting to power generation operation lines that decrease power output or engine speed, and implementing low load operations when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the engine is driven under high load conditions to generate electric power, then the power generation capability is improved, but the catalyst temperature increases leading to deactivation
Solution Approach 1:
The patent dynamically adjusts the engine operating point based on real-time catalyst temperature monitoring. When catalyst temperature reaches a predetermined threshold, the control device shifts the engine operating point from high load conditions to reduced load conditions, creating a dynamic response that balances power generation needs with catalyst temperature control
Solution Approach 2:
The patent changes the engine operating parameters (load and speed) in response to catalyst temperature conditions. By modifying these parameters, the system reduces exhaust gas temperature and consequently catalyst temperature while maintaining the ability to generate electric power when conditions permit
2Temperature
If the engine operating point is changed to reduce exhaust gas temperature, then the catalyst temperature is reduced, but the power generation amount decreases
Solution Approach 1:
The patent implements periodic adjustment of engine operating conditions based on catalyst temperature thresholds. The system alternates between normal power generation operation and temperature reduction operation, creating a periodic pattern that maintains catalyst health while preserving overall power generation capability
Solution Approach 2:
The patent applies partial action by reducing engine load only to the extent necessary to control catalyst temperature, rather than completely shutting down power generation. This partial reduction in operating point achieves temperature control while minimizing impact on power generation output
Data Source
AI summary
A control device for a series hybrid vehicle, the series hybrid vehicle including: an engine, a catalyst that is disposed in an exhaust path of the engine, a generator that generates electric power using power output from the engine, a battery that stores the electric power generated by the generator, and a traction electric motor that is driven with electric power of the battery, the control device including an electronic control unit configured to: acquire information on a temperature of the catalyst; and, when the information on the temperature of the catalyst is information corresponding to the temperature of the catalyst being equal to or higher than a predetermined temperature, change an operating point of the engine to an operating point that reduces a temperature of the exhaust gas while generating the electric power by the generator.