Hybrid Vehicle Catalyst Control for Emission Performance
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Solution Overview
Problem
In hybrid vehicles, the catalyst in the exhaust emission control device deteriorates when exposed to a lean atmosphere during engine stoppage, leading to poor emission performance upon subsequent engine starts, due to increased oxygen storage.
Innovation Solution
A hybrid vehicle control system that continues fuel injection until a predetermined condition is met when the catalyst temperature is above a certain threshold, and immediately stops fuel injection when below this threshold, to prevent exposure to a lean atmosphere and reduce oxygen storage, thereby maintaining catalyst conversion performance and minimizing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If fuel injection is immediately stopped when the engine stop is requested, then fuel consumption is reduced, but the catalyst is exposed to a lean atmosphere causing oxygen storage increase and conversion performance deterioration
Solution Approach 1:
The control device changes the parameter of fuel injection timing based on the catalyst temperature parameter. When catalyst temperature is above the predetermined threshold, fuel injection continues until the air-fuel ratio reaches a predetermined value; when below the threshold, fuel injection is immediately stopped. This parameter-based conditional control resolves the contradiction by adapting fuel injection strategy to catalyst thermal state.
2Reliability
If fuel injection is continued until a predetermined condition is satisfied when catalyst temperature is high, then catalyst conversion performance is maintained, but fuel consumption increases
Solution Approach 1:
The system dynamically adjusts fuel injection duration based on catalyst temperature parameter. By setting a temperature threshold and corresponding fuel injection strategy, the system optimizes the balance between catalyst performance maintenance and fuel consumption minimization.
Solution Approach 2:
The control device uses feedback from catalyst temperature sensing to determine fuel injection strategy. The predetermined condition (air-fuel ratio threshold) serves as a feedback target that stops fuel injection when achieved, preventing excessive fuel consumption while ensuring catalyst performance.
3Quantity of substance
If the catalyst is exposed to a lean atmosphere during engine stop, then oxygen storage in the catalyst increases, but this leads to poor emission performance after engine restart
Solution Approach 1:
The system takes preliminary anti-action by controlling fuel injection during the engine stop period to prevent the harmful effect of excessive oxygen storage. By maintaining a predetermined air-fuel ratio when catalyst temperature is high, the system preemptively prevents the condition that would lead to poor emission performance after restart.
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
This configuration effectively suppresses catalyst deterioration and subsequent poor emissions by maintaining optimal catalyst conditions and reducing fuel consumption by ensuring appropriate air-fuel ratios and valve timing, while preventing unnecessary fuel use when the catalyst is not activated.
Implementation Method 1
the catalyst is likely to increase the amount of oxygen storage and deteriorate the conversion performance
Implementation Method 2
the control device continues fuel injection of the engine until satisfaction of a predetermined condition
Data Source
AI summary
When a temperature of a catalyst in an exhaust emission control device mounted in an exhaust system of an engine is equal to or higher than a predetermined temperature at a time of a request for stopping the engine, a hybrid vehicle including the engine and a motor continues fuel injection of the engine until satisfaction of a predetermined condition and stops fuel injection of the engine on satisfaction of the predetermined condition. When the temperature of the catalyst is lower than the predetermined temperature at the time of the request for stopping the engine, on the other hand, the hybrid vehicle immediately stops fuel injection of the engine.