Engine Control Unit Combustion Mode Switching for Cylinder Temperature
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Solution Overview
Problem
The existing internal combustion engine control methods fail to prevent abnormal combustion, such as pre-ignition or knocking, when the characteristic switching mechanism fails, leading to excessive cylinder temperature and misfiring due to the inability to switch the exhaust valve lift characteristic from the second to the first lift characteristic during flame propagation combustion.
Innovation Solution
The internal combustion engine incorporates an electronic control unit that switches to homogeneous combustion in the flame ignition operation range and spray-guided stratified combustion in the compression ignition operation range when a switching failure occurs, along with adjusting throttle and waste gate valve openings and exhaust phase timing to minimize internal EGR gas and cylinder temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the characteristic switching mechanism is used to switch the exhaust valve lift characteristic to the second lift characteristic in the compression ignition operation range, then the cylinder temperature is increased to enable pre-mixture compression ignition combustion, but when switching failure occurs, the cylinder temperature becomes excessively high causing abnormal combustion in the flame propagation combustion range
Solution Approach 1:
The electronic control unit monitors the operation range and detects switching failure conditions, then provides feedback control by switching to alternative combustion modes (homogeneous combustion or spray-guided stratified combustion) to maintain reliable operation. This feedback mechanism prevents abnormal combustion by adapting the combustion strategy based on the actual operational state and switching mechanism performance.
Solution Approach 2:
The system dynamically adjusts the combustion mode based on the operation range and switching mechanism status. The electronic control unit can switch between different combustion modes (pre-mixture compression ignition, homogeneous combustion, spray-guided stratified combustion) to adapt to changing conditions, ensuring stable operation even when the characteristic switching mechanism fails.
2Adaptability or versatility
If the exhaust valve is opened in both exhaust stroke and intake stroke to enable pre-mixture compression ignition combustion, then high-temperature exhaust gas is sucked back into the cylinder to increase cylinder temperature, but this causes excessive temperature and abnormal combustion when flame propagation combustion is required
Solution Approach 1:
The electronic control unit changes operational parameters (combustion mode, valve timing characteristics) based on the detected operation range and switching mechanism status. By switching between homogeneous combustion, spray-guided stratified combustion, and pre-mixture compression ignition combustion, the system adapts parameters to prevent abnormal combustion while maintaining combustion mode flexibility.
Solution Approach 2:
The operation range is segmented into different zones (compression ignition operation range, flame ignition operation range) with distinct combustion strategies. The electronic control unit selects appropriate combustion modes for each segment, preventing the harmful effects of exhaust gas recirculation in flame propagation combustion while enabling pre-mixture compression ignition where needed.
3Device complexity
If the lift characteristic switching is not performed due to mechanism failure, then the device complexity is reduced, but the harmful effect of excessive cylinder temperature and pre-ignition increases
Solution Approach 1:
The electronic control unit automatically detects switching failure conditions and self-corrects by switching to alternative combustion modes without requiring additional mechanical switching mechanisms. This self-service approach maintains engine reliability while avoiding the need for more complex mechanical redundancy, preventing excessive cylinder temperature through electronic control adaptation.
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 configuration effectively prevents abnormal combustion and misfiring by stabilizing combustion and reducing cylinder temperature, even when the characteristic switching mechanism fails, ensuring reliable engine operation.
Implementation Method 1
a fuel injection valve configured to directly inject fuel into a combustion chamber of the internal combustion engine
Implementation Method 2
An electrode portion of the spark plug is disposed in one of the inside of a fuel injection path and the vicinity of the fuel injection path
Implementation Method 3
The characteristic switching mechanism is configured to switch a lift characteristic between a first lift characteristic and a second lift characteristic. The first lift characteristic is a lift characteristic of an exhaust valve of opening the exhaust valve in an exhaust stroke
Implementation Method 4
The electronic control unit is configured to control the fuel injection valve and the spark plug such that fuel is combusted by one of pre-mixture compression ignition combustion and flame propagation combustion
Data Source
Figure 1
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AI summary
An electronic control unit (200) of an internal combustion engine (100) is configured to control the fuel injection valve (20) and to control a spark plug (16) if necessary such that fuel is combusted by pre-mixture compression ignition combustion or flame propagation combustion. The electronic control unit (200) is configured to perform homogeneous combustion in a flame ignition operation range when switching failure has not occurred, the homogeneous combustion being combustion in which fuel homogeneously diffused into the combustion chamber (11) is ignited using the spark plug (16) and is combusted by flame propagation combustion. The electronic control unit (200) is configured to perform spray-guided stratified combustion in a second operation range when the switching failure has occurred, the spray-guided stratified combustion being combustion in which fuel in the fuel injection path is ignited using the spark plug (16) and is combusted by the flame propagation combustion.