Engine Stop Control Using Particulate Filter Soot Loading
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Solution Overview
Problem
Direct injection spark ignition engines generate more soot than port injected engines at certain conditions, particularly at lower engine temperatures, which can lead to increased soot flow through particulate filters, resulting in higher emissions and reduced fuel efficiency.
Innovation Solution
Adjusting the automatic engine stopping temperature threshold based on the amount of soot stored in the particulate filter, allowing the engine to be stopped at lower temperatures when soot trapping efficiency is high and at higher temperatures when efficiency is low, thereby reducing soot emissions and improving fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine is stopped at lower temperatures to improve fuel efficiency, then fuel consumption decreases, but soot may pass through the particulate filter increasing emissions
Solution Approach 1:
The automatic engine stopping system uses dynamic temperature thresholds instead of fixed values. The threshold adapts in real-time based on particulate filter soot loading status, allowing the engine to be stopped at lower temperatures when the filter is loaded (improving fuel efficiency) while preventing soot escape when the filter is clean.
Solution Approach 2:
The system continuously monitors particulate filter soot loading conditions and uses this feedback to adjust the engine stopping temperature threshold. This closed-loop control ensures that engine stopping decisions are made with knowledge of current filter efficiency, balancing fuel savings against emissions control.
2Productivity
If the engine is stopped frequently to reduce emissions and improve fuel efficiency, then fuel consumption and emissions decrease, but system complexity increases due to temperature threshold management
Solution Approach 1:
The engine control unit performs multiple functions: it manages normal engine operation, monitors particulate filter soot loading, determines optimal stopping temperatures, and controls engine shutdown decisions. This multi-functionality avoids adding dedicated hardware while achieving sophisticated emissions and fuel efficiency management.
Data Source
AI summary
Systems and methods for operating a spark ignition engine that includes a particulate filter in the engine's exhaust system are described. In one example, a threshold temperature at which the spark ignition engine may be automatically stopped is adjusted according to an amount of soot that is stored in the particulate filter.