Spark-Ignition Engine Control System Vortex Center Adjustment
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Solution Overview
Problem
In spark-ignition internal combustion engines, controlling the flow rate of gas around the ignition plug at ignition timing is challenging, especially at varying engine speeds, leading to unstable ignition performance during lean burn operations or when the air-fuel mixture is lean.
Innovation Solution
A control system that adjusts the position of the vortex center of the tumble flow by varying the fuel or burned gas injection timing, amount, and pressure to optimize the flow rate around the ignition plug, ensuring it remains within a suitable range for ignition, regardless of engine speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tumble ratio is controlled to be within a certain definite range, then the combustion stability is improved, but the flow rate of gas around the ignition plug becomes excessively high at high engine speeds, deteriorating ignition performance
Solution Approach 1:
The tumble flow is segmented into multiple regions with different flow rates by positioning the vortex center away from the ignition plug. This allows the overall tumble flow to maintain high speed for combustion stability while the region around the ignition plug has controlled flow rate for proper ignition.
Solution Approach 2:
The flow rate characteristics are made non-uniform across the combustion chamber by controlling the vortex center position. The area around the ignition plug has different flow properties (lower flow rate) compared to other regions, optimizing ignition conditions locally while maintaining overall tumble flow effectiveness.
2Reliability
If the tumble flow control valve opening is adjusted to maintain tumble ratio within permissible range, then misfiring is avoided, but ignition performance deteriorates when engine speed increases due to excessively high gas flow rate around ignition plug
Solution Approach 1:
The vortex center position is dynamically adjusted based on engine operating conditions, particularly engine speed. By making the vortex center position variable rather than fixed, the system can optimize both combustion stability and ignition performance across different operating ranges.
Solution Approach 2:
The vortex center acts as an intermediary element that mediates between the requirements for high tumble flow (combustion stability) and low local flow rate (ignition performance). By positioning the vortex center appropriately, it creates a flow pattern that satisfies both competing requirements.
3Reliability
If fuel injection amount is increased to maintain combustion stability in lean burn operation, then misfiring is reduced, but the flow rate of gas around ignition plug increases, worsening ignition performance
Solution Approach 1:
The fuel injection is segmented into multiple stages with different purposes. The first injection establishes baseline combustion stability, while subsequent injections are timed to coincide with reduced flow rates around the ignition plug, ensuring proper ignition without excessive overall fueling.
Solution Approach 2:
Fuel injection is performed in advance of ignition timing to allow proper mixing and preparation of the air-fuel mixture. By controlling the injection timing and duration, the system prepares the mixture for stable combustion while managing the flow rate characteristics during the ignition event.
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 stabilizes ignition performance by maintaining an optimal flow rate around the ignition plug, reducing ignition lag and torque fluctuations, even at high engine speeds, thereby improving combustion efficiency and reducing the risk of misfiring.
Implementation Method 1
increase the flow rate of the above-indicated part of the tumble flow by using jet flow of the fuel injected from the fuel injection valve
Implementation Method 2
an ignition plug configured to ignite an air-fuel mixture in the cylinder
Implementation Method 3
a tumble flow control valve that produces tumble flow in each cylinder
Data Source
AI summary
A control system for a spark-ignition internal combustion engine configured to produce tumble flow in a cylinder is provided. The spark-ignition internal combustion engine includes an ignition plug configured to ignite an air-fuel mixture in the cylinder. The control system includes a tumble flow rate controller configured to change a position of a vortex center of the tumble flow as viewed in a direction of a center axis of the cylinder, so as to control a flow rate of the tumble flow around the ignition plug at the ignition timing of the ignition plug.