Engine Fuel Injection Timing Control for Catalyst Activation
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Solution Overview
Problem
The existing control methods for internal combustion engines that overlap fuel injection periods with spark plug high voltage application can lead to unstable combustion states when the igniting environment changes, resulting in significant combustion fluctuations between cycles, affecting drivability.
Innovation Solution
A control device that adjusts the timing of fuel injections relative to the ignition period, allowing the initial flame to grow before contacting the second fuel injection, and modifies the interval between the start of the ignition period and the completion of the second injection based on combustion fluctuation parameters to ensure reliable flame growth and stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuel injection period is made to overlap with the high voltage application period to improve ignitability, then the exhaust gas cleaning catalyst activation is enhanced, but combustion fluctuation between cycles increases when the igniting environment changes
Solution Approach 1:
The control device dynamically adjusts the injection timing based on detected combustion fluctuation. When combustion fluctuation is detected, the system retards the injection timing relative to the ignition timing, creating a controlled time interval that prevents unstable combustion while maintaining catalyst activation effectiveness.
Solution Approach 2:
The system continuously monitors combustion fluctuation through detection means and uses this feedback to adjust the injection timing. The control device compares the detected fluctuation level against predetermined thresholds and modifies the injection timing accordingly, creating a closed-loop control system that maintains combustion stability while ensuring catalyst activation.
2Stability of the object's composition
If the injection timing is retarded to prevent combustion fluctuation, then combustion stability improves, but the overlap between injection and ignition periods is reduced
Solution Approach 1:
The system dynamically adjusts the time interval between injection completion and ignition based on real-time combustion fluctuation detection. When fluctuation is detected, the interval is increased by retarding injection timing; when combustion is stable, the interval is reduced to maintain better overlap for catalyst activation.
Solution Approach 2:
The control device changes the temporal parameter (time interval between injection and ignition) based on combustion conditions. By adjusting this parameter dynamically, the system optimizes both combustion stability and catalyst activation reliability under different operating conditions.
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 suppresses combustion fluctuations between cycles by ensuring sufficient contact between the initial flame and the second fuel injection, maintaining stable combustion even when the igniting environment is out of the desired range, while also ensuring efficient activation of the exhaust gas cleaning catalyst.
Implementation Method 1
a low pressure area is formed by entraining air around the fuel spray injected from each injection hole (entrainment)
Implementation Method 2
The spark plug is configured to ignite an air-fuel mixture in the cylinder using a discharge spark
Data Source
AI summary
In a catalyst warming-up control, a first time injection is performed by an injector in an intake stroke. A second time injection is performed with an amount smaller than the first time injection in an expansion stroke after a compression top dead center. In the catalyst warming-up control, an interval from the start of the ignition period of an spark plug to the completion of the second time injection is controlled by the ECU so that the initial flame generated from an air-fuel mixture containing the fuel spray injected by the first time injection is brought into contact with the fuel spray injected by the second time injection.