Engine Control Method Using Tumble Flow for Combustion Timing
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Solution Overview
Problem
In engines with increased geometric compression ratios, spark ignition can lead to abnormal combustion such as knocking, which decreases thermal efficiency.
Innovation Solution
The engine control method creates a broken reaction zone by generating a strong tumble flow and supplying fuel to produce a lean air-fuel mixture. The ignition unit sparks the mixture within this zone, causing the flame to be stored until conditions change, allowing autoignition to initiate combustion near the compression top dead center.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If spark ignition is delayed to reduce abnormal combustion, then knocking is reduced, but the combustion period becomes longer and the combustion center of gravity moves away from the compression top dead center, decreasing thermal efficiency
Solution Approach 1:
The ignition unit makes flame in advance during the compression stroke when tumble ratio is high, storing the flame before combustion actually progresses. This preliminary flame creation allows the combustion to be initiated earlier while still controlling the main combustion phase to avoid knocking
Solution Approach 2:
The invention utilizes changes in tumble ratio as a parameter to control combustion. By creating flame when tumble ratio is high (broken reaction zone conditions) and then allowing autoignition when conditions change, the system optimizes both knocking reduction and thermal efficiency
2Use of energy by moving object
If a strong tumble flow is created to produce a broken reaction zone, then the flame is stored and autoignition occurs near top dead center improving thermal efficiency, but the device complexity increases due to precise timing requirements
Solution Approach 1:
The control unit monitors tumble ratio and uses this feedback to determine the optimal timing for flame creation. This feedback mechanism allows the system to adapt to varying engine conditions while maintaining the precise timing needed for broken reaction zone combustion
Solution Approach 2:
The system uses the engine's own tumble flow characteristics to create the broken reaction zone conditions. The natural compression stroke and tumble port geometry work together with the ignition timing to achieve the desired combustion mode without requiring additional mechanical components
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 improves thermal efficiency by reducing knocking and shortening the combustion period, while maintaining a center of gravity close to the compression top dead center for enhanced engine performance.
Implementation Method 1
creating, using a tumble port, a strong tumble flow in the combustion chamber
Implementation Method 2
an ignition unit arranged in the combustion chamber makes flame after the supply of the fuel into the combustion chamber
Implementation Method 3
combustion of the air-fuel mixture is started by the stored flame by auto-ignition
Data Source
Figure 1
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AI summary
The engine control method includes a fuel supply step (6041) and an ignition step (6042). In the fuel supply step, the fuel supply unit (injector 6) supplies the fuel into the combustion chamber (17). In the ignition step, an ignition unit (spark plug 25) arranged in the combustion chamber makes flame after the supply of the fuel into the combustion chamber and at a timing when the flow strength in the combustion chamber is greater than a predetermined value in a compression stroke during or before a post-mid stage where the compression stroke is divided into four stages of a pre-stage, a pre-mid stage, a post-mid stage, and a post-stage.