Engine Control Stabilizing Combustion During Catalyst Warm-Up
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Solution Overview
Problem
Internal combustion engines experience unstable combustion during catalyst warming-up due to frequent variations in mechanical compression ratio and combustion mode changes in response to acceleration requests, leading to incomplete catalyst warming.
Innovation Solution
Implementing a compression ratio fixing control that maintains a predetermined low mechanical compression ratio and stratified combustion during engine idling for catalyst warming-up, switching to homogeneous combustion upon catalyst warming completion, prioritizing combustion stability over compression ratio adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the mechanical compression ratio is frequently adjusted in response to acceleration requests during catalyst warming-up, then the catalyst warming-up speed is improved, but the combustion stability deteriorates
Solution Approach 1:
The patent applies parameter changes by switching between different compression ratio modes (first compression ratio mode for warming-up, second compression ratio mode for normal operation) based on catalyst temperature conditions. This allows the system to optimize both catalyst warming speed and combustion stability by selecting appropriate compression ratio parameters according to operational state.
Solution Approach 2:
The patent implements dynamics through dynamic switching between compression ratio modes based on real-time catalyst temperature monitoring. The system transitions from a fixed low compression ratio during warming-up to variable compression ratio based on accelerator pedal position once warming is complete, enabling adaptive optimization of both warming speed and combustion stability.
2Productivity
If the mechanical compression ratio is reduced to raise exhaust temperature for catalyst warming-up, then the catalyst warming-up efficiency is improved, but the combustion stability deteriorates due to frequent variations
Solution Approach 1:
The patent applies preliminary action by establishing a predetermined first compression ratio mode specifically for catalyst warming-up operations. This pre-defined mode ensures consistent low compression ratio during the warming-up phase, preventing frequent variations and maintaining combustion stability while efficiently raising exhaust temperature for catalyst warming.
Solution Approach 2:
The system uses parameter changes to switch between compression ratio modes based on catalyst temperature conditions. During warming-up, a fixed low compression ratio is maintained to optimize warming efficiency. Once warming is complete, the system transitions to a second compression ratio mode that varies with accelerator pedal position, thus maintaining stability during the transition and preventing frequent mode switching.
3Power
If the compression ratio is increased in response to acceleration requests during catalyst warming-up, then the power output is improved, but the combustion stability deteriorates due to frequent compression ratio changes
Solution Approach 1:
The patent implements dynamics through conditional switching between compression ratio modes. During catalyst warming-up, the system maintains a fixed first compression ratio regardless of acceleration requests to ensure combustion stability. Only after warming is complete does the system switch to a second compression ratio mode that dynamically responds to accelerator pedal position, thus providing power optimization without compromising stability during the critical warming-up phase.
Solution Approach 2:
The system applies preliminary action by pre-establishing a fixed compression ratio mode for the warming-up phase, preventing premature or frequent compression ratio adjustments. This preliminary setting ensures that power requests during warming-up do not trigger unstable compression ratio changes, while still allowing power optimization to be implemented once the catalyst reaches operating 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 stabilizes combustion by maintaining a consistent low compression ratio and combustion mode during incomplete catalyst warming, ensuring stable engine operation and minimizing the impact on fuel efficiency and performance.
Implementation Method 1
perform stratified combustion in a cylinder of the internal combustion engine
Implementation Method 2
perform homogeneous combustion in the cylinder
Data Source
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AI summary
A control method for an internal combustion engine including a variable compression ratio mechanism. The method includes: implementing a compression ratio fixing control in which a mechanical compression ratio is fixed to a predetermined low compression ratio, and controlling combustion form in a cylinder to stratified combustion, under engine idling during catalyst warming-up; controlling the combustion form in the cylinder to homogeneous combustion, under an operation state other than the engine idling during the catalyst warming-up; and implementing the compression ratio fixing control and controlling the combustion form in the cylinder to the homogeneous combustion, in response to pressing-down of an accelerator under the engine idling during the catalyst warming-up, and as long as the engine idling during the catalyst warming-up has a possibility to resume in response to release of the accelerator after the pressing-down.