Direct Injection Engine Control for PM Reduction
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Solution Overview
Problem
Cylinder injection engines face challenges in reducing particulate matter (PM) emissions while maintaining combustion stability, as existing methods often result in increased PM production due to oxygen deficiency and fuel adherence issues during fuel injection.
Innovation Solution
A control device for a cylinder injection engine that performs multiple first injections to produce a lean air-fuel mixture and a single second injection to produce a rich air-fuel mixture immediately before ignition, creating a stratified air-fuel mixture with the rich mixture centered around the ignition position and leaner towards the cylinder walls, reducing fuel adherence and PM production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple injections are performed to produce a stratified air-fuel mixture with rich portions, then combustion stability is improved, but PM emission increases due to oxygen deficiency in rich portions
Solution Approach 1:
The fuel injection is divided into multiple separate injection events (first injection, second injection, third injection) with different purposes and timing. The first injection produces a lean air-fuel mixture, the second injection creates a localized rich air-fuel mixture near the ignition plug, and the third injection provides additional fuel enrichment. This segmentation allows the system to achieve combustion stability through the rich mixture near the ignition plug while limiting overall PM formation by controlling the distribution and amount of rich mixture regions.
Solution Approach 2:
The patent creates a localized rich air-fuel mixture specifically in the region around the ignition plug through the second injection, while maintaining a lean air-fuel mixture in other regions of the combustion chamber. This local quality approach ensures that the rich mixture is confined to where it is most needed for ignition reliability, thereby reducing overall PM emissions while maintaining combustion stability.
2Object-generated harmful factors
If the fuel injection amount immediately before ignition is reduced to decrease PM, then PM emission is reduced, but combustion stability deteriorates
Solution Approach 1:
The first injection is performed in advance to produce a lean air-fuel mixture in the combustion chamber before the second injection creates the localized rich mixture. This preliminary action of creating a lean background mixture allows the subsequent rich injection to be more effective at the ignition location while limiting the overall volume of rich mixture, thus reducing PM while maintaining combustion stability.
3Reliability
If the fuel injection amount during intake stroke is increased to maintain combustion stability, then combustion stability is improved, but fuel adherence to cylinder wall surface increases
Solution Approach 1:
The patent uses periodic, pulsed fuel injections instead of continuous injection. The fuel is injected in discrete amounts at specific intervals (first injection, second injection, third injection) corresponding to different phases of the combustion cycle. This periodic action allows precise control over when and where fuel is delivered, ensuring fuel is injected only when and where it is needed for combustion, thereby minimizing fuel adherence to cylinder walls while maintaining combustion stability.
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 PM production and ensures combustion stability by enriching the air-fuel mixture towards the ignition center, improving exhaust emissions and maintaining ignitability and combustion performance.
Implementation Method 1
a fuel injection valve (21) to inject fuel into a combustion chamber (23)
Implementation Method 2
before an ignition device performs an ignition
Data Source
AI summary
An engine (10) is a cylinder injection engine, and includes an injector (21) that directly injects a fuel into a combustion chamber (23), and an ignition plug (34) that generates an ignition spark in the combustion chamber (23). An ECU (40) performs multiple first injections to each produce an air-fuel mixture of a lean air-fuel ratio in the combustion chamber (23) before an ignition in one combustion cycle of the engine, and performs a second injection to produce an air-fuel mixture of a rich air-fuel ratio in the combustion chamber (23) before the ignition and after the first injection. In particular, the ECU implements the multiple first injections in such a manner that the first injection implemented early among the multiple first injections produces an air-fuel mixture leaner than that of the first injection implemented subsequently. The ECU implements the second injection only once immediately before an ignition timing.