Particulate Filter Regeneration via Vacuum Pump During Engine Shutdown
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Solution Overview
Problem
Direct injection engines face challenges in maintaining accurate emission control during particulate filter regeneration due to increased soot production, particularly during high load and high speed conditions, which affects engine efficiency and emissions.
Innovation Solution
A method involving the use of a vacuum pump to draw fresh air through the exhaust system and into the intake system during engine shutdown, facilitating particulate filter regeneration, either through an exhaust gas recirculation system or positive valve overlap, to reduce the impact on engine-running emissions and enhance regeneration efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If particulate filter regeneration is performed during engine operation, then soot accumulation is reduced, but engine-running emissions increase and fuel consumption rises
Solution Approach 1:
The system performs filter regeneration during engine shutdown periods before the filter becomes fully loaded with soot. By proactively regenerating the filter during idle time, the system prevents excessive soot accumulation without requiring additional fuel consumption during active engine operation, thus maintaining filter performance while avoiding increased running emissions
2Power
If direct injection engines operate at high load and high speed, then power output increases, but soot production increases due to insufficient air-fuel mixing
Solution Approach 1:
The system converts the harmful effect of high soot production during high-load operation into a beneficial regeneration process. By capturing the excess soot generated during high-power operation and subsequently burning it off during engine shutdown periods, the system allows the engine to operate at high power when needed while using the idle time to eliminate the harmful soot accumulation through controlled combustion
3Object-generated harmful factors
If engine shutdown time is extended for filter regeneration, then emission control improves, but vehicle availability decreases
Solution Approach 1:
The system implements periodic regeneration cycles during naturally occurring engine shutdown periods (such as traffic lights, stop-and-go conditions, or planned idle periods) rather than requiring extended continuous shutdown. This approach maintains emission control by regularly burning off soot accumulation while minimizing impact on vehicle availability, as regeneration occurs during brief idle intervals throughout normal operation
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 approach allows for effective particulate filter regeneration during engine shutdown, reducing the need for engine-running regeneration and minimizing emissions, thereby improving emission control and engine efficiency.
Implementation Method 1
operating a vacuum pump to draw fresh air through the exhaust system to an intake system
Implementation Method 2
an exhaust gas recirculation (EGR) system may be employed to facilitate regeneration of the particulate filter
Implementation Method 3
fresh air containing oxygen (e.g., O2) may be drawn through the particulate filter thus assisting in regeneration of the particulate filter
Implementation Method 4
regenerating at least a portion of the particulate filter during the engine rest
Data Source
AI summary
Various systems and method are described for controlling an engine having an exhaust system which includes a particulate filter. One example method comprises, after shutting down the engine and spinning down the engine to rest, operating a vacuum pump to draw fresh air through the exhaust system to an intake system, and regenerating at least a portion of the particulate filter during the engine rest.