Hybrid Vehicle Catalyst Temperature Control via Engine Operating Point Shift
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Solution Overview
Problem
In hybrid vehicles equipped with internal combustion engines and turbocharged forced induction devices, the exhaust gas temperature is lowered, leading to catalyst poisoning due to sulfur adsorption, which impairs the catalyst's purifying ability and can result in either poor function or degradation.
Innovation Solution
A hybrid vehicle system that includes a controller to manage the internal combustion engine and rotating electric machine, shifting the operating point on a map to maintain the catalyst temperature within an appropriate range, thereby preventing poisoning and degradation while maintaining consistent power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the turbocharger uses exhaust gas energy to boost suctioned air, then the engine's power output is improved, but the exhaust gas temperature is lowered causing catalyst poisoning
Solution Approach 1:
The control device changes the operating parameters of the engine by shifting the operating point on the map to a different rotation speed and torque combination. This parameter change allows the exhaust gas temperature to be increased to a predetermined value or higher, preventing catalyst poisoning while maintaining the power output requirement through the isopower line constraint
2Reliability
If the exhaust gas temperature is increased to recover the catalyst from sulfur poisoning, then the catalyst's purifying ability is restored, but the catalyst may undergo degradation when excessively hot
Solution Approach 1:
The control device implements a feedback mechanism by monitoring the catalyst temperature and adjusting the operating point accordingly. When catalyst temperature is below the appropriate range, the operating point is shifted to increase temperature and recover from poisoning. When temperature exceeds the appropriate range, the operating point is shifted to decrease temperature and prevent degradation, maintaining temperature within the target range
3Temperature
If the operating point is shifted on the map to control catalyst temperature, then the catalyst temperature is maintained within appropriate range, but the power output may fluctuate
Solution Approach 1:
The system dynamically adjusts the operating point on the map based on real-time catalyst temperature conditions. The control device shifts the operating point to different rotation speed and torque combinations that maintain the required power output while achieving the desired catalyst temperature control, adapting to changing conditions through continuous adjustment
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 prevents catalyst poisoning and degradation by maintaining the catalyst temperature within an optimal range, restoring its purifying ability and ensuring consistent vehicle performance without significant power fluctuations.
Implementation Method 1
the internal combustion engine includes a forced induction device which uses energy of exhaust gas emitted from the internal combustion engine to boost suctioned air to be fed to the internal combustion engine
Implementation Method 2
a catalyst that purifies exhaust gas of the internal combustion engine
Implementation Method 3
as a component of sulfur contained in fuel, lubricant or the like adsorbs to the catalyst, the catalyst may be poisoned by sulfur
Data Source
AI summary
A hybrid vehicle includes: an internal combustion engine; a rotating electric machine; a planetary gear mechanism to which the internal combustion engine, the rotating electric machine and an output shaft are connected; a catalyst that purifies exhaust gas of the internal combustion engine; and a controller that controls the internal combustion engine and the rotating electric machine. The controller controls the internal combustion engine and the rotating electric machine to perform catalyst temperature control to shift an operating point on a map representing a relationship between rotation speed of the internal combustion engine and torque generated by the internal combustion engine so that the catalyst has a temperature within an appropriate temperature range. Degradation of the catalyst can be suppressed without deteriorating the function of the catalyst.