Engine Control Device Synchronizing Ignition Timing and Compression Ratio
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Solution Overview
Problem
Current engine control devices that aim to warm up catalysts by suppressing rich air-fuel ratios in the combustion chamber lead to decreased combustion stability, resulting in increased particulate matter and number (PM/PN), which hampers the effectiveness of the catalyst warm-up mode.
Innovation Solution
An engine control device that synchronously controls ignition timing and actual compression ratio during the catalyst warm-up mode to enhance exhaust and combustion chamber temperatures, thereby suppressing PM/PN production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the air-fuel ratio in the combustion chamber is suppressed from becoming rich to avoid excessive fuel consumption, then fuel efficiency is improved, but combustion stability deteriorates leading to increased PM/PN emissions
Solution Approach 1:
The patent segments the fuel injection process into two distinct phases: a first fuel injection during the compression stroke that creates a locally rich mixture near the spark plug for stable combustion, and a second fuel injection at a timing ahead of ignition that supplies air to the spark plug region. This segmentation allows different air-fuel ratios in different spatial and temporal zones, achieving both combustion stability and reduced overall fuel consumption.
Solution Approach 2:
The patent applies local quality by creating a locally rich air-fuel mixture specifically around the spark plug during the first fuel injection, while maintaining a leaner overall mixture in the combustion chamber. This localized enrichment ensures stable combustion at the ignition point without requiring the entire combustion chamber to be rich, thereby reducing overall fuel consumption and PM/PN emissions while maintaining combustion stability.
2Temperature
If ignition timing is retarded to warm up the catalyst, then exhaust temperature increases enabling early catalyst activation, but combustion chamber temperature decreases causing increased PM/PN
Solution Approach 1:
The patent performs preliminary action by conducting the first fuel injection during the compression stroke, before ignition occurs. This timing allows the rich mixture to be prepared and concentrated near the spark plug region in advance, ensuring that when ignition happens (even with retarded timing), there is sufficient fuel concentration at the ignition point to maintain stable combustion and adequate combustion chamber temperature, preventing PM/PN formation despite lower exhaust temperatures from retarded ignition.
Solution Approach 2:
The patent changes the parameter of air-fuel ratio distribution by implementing dual fuel injection strategies with different timing and distribution patterns. The first injection creates a locally rich mixture near the spark plug, while the second injection timing is optimized to supply air to the spark plug region. This parameter change allows the system to maintain combustion stability and temperature even with retarded ignition timing, reducing PM/PN emissions while still achieving catalyst warm-up through increased exhaust temperature.
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 effectively activates the catalyst by increasing exhaust temperature and combustion chamber temperature, thereby reducing PM/PN emissions while maintaining combustion stability.
Implementation Method 1
a catalyst warm-up mode that increases exhaust temperature by retarding ignition timing after the engine starts
Implementation Method 2
there is a possibility that fuel that is oxidized at low temperatures may become soot, producing PM/PN
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Provided is an engine control device that can suppress an increase in PM/PN in an engine that performs a catalyst warm-up mode. To do so, the engine control device according to the present invention synchronously controls ignition timing and an actual compression ratio of the engine in the catalyst warm-up mode.