Internal Combustion Engine Tumble Control Valve Switching
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Solution Overview
Problem
Internal combustion engines face challenges in quickly switching from a stoichiometric mode to a homogeneous lean mode while ensuring stable combustion, particularly in regions with low intake load factors where combustion robustness is low.
Innovation Solution
The engine employs an air flow control valve to adjust the air flow strength in the combustion chamber and a controller that sets a waiting time for switching the combustion mode based on the operational region, increasing the waiting time in regions with low intake load factors to maintain stability and reducing it in regions with higher robustness for quicker switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the waiting time for switching combustion mode is shortened to improve fuel economy, then the switching speed from stoichiometric mode to homogeneous lean mode increases, but the combustion stability deteriorates in low intake load factor regions
Solution Approach 1:
The patent applies dynamics by making the waiting time variable rather than fixed. The control device dynamically adjusts the waiting time based on the current operating conditions (intake load factor and engine speed). When the operating point is in a region with low combustion robustness, the waiting time is extended to ensure stable combustion. When the operating point is in a region with high combustion robustness, the waiting time is reduced to enable faster mode switching and improve fuel economy. This dynamic adjustment resolves the contradiction between switching speed and combustion stability.
2Use of energy by moving object
If the air-fuel ratio is made leaner to improve fuel economy, then the fuel consumption decreases, but the combustion robustness decreases in certain operational regions
Solution Approach 1:
The patent applies parameter changes by adjusting the air-fuel ratio based on operating conditions. The control device selects different target air-fuel ratios depending on the intake load factor and engine speed. In regions where combustion robustness is sufficient, the system operates with a leaner air-fuel ratio to improve fuel economy. In regions where combustion robustness is low, the system maintains a richer air-fuel ratio to ensure stable combustion. This conditional parameter adjustment resolves the contradiction between fuel economy and combustion robustness.
Data Source
AI summary
When switching the combustion mode from a stoichiometric mode to a homogeneous lean mode, a controller starts switching of the combustion mode after switching of the opening angle of a tumble control valve is started. When a target operating point of an internal combustion engine lies outside a predetermined operational region that is set in a range that excludes at least a low intake load factor region and includes at least a medium intake load factor and medium engine speed region, the controller sets the waiting time from the start of switching of the opening angle of the tumble control valve to the start of switching of the combustion mode to be longer than when the target operating point lies in the predetermined operational region.