Engine Control Device Combustion Stability Near Dilution Limit
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Solution Overview
Problem
Existing internal combustion engine control devices struggle to maintain optimal dilution levels, leading to inefficiencies and potential for improved fuel consumption performance.
Innovation Solution
A control device that calculates the change amount of a combustion state parameter and adjusts the operation of actuators, such as the EGR valve, to bring the dilution close to its limit value, thereby optimizing engine operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If dilution combustion is used to reduce fuel consumption, then pump loss and cooling loss are reduced, but the air-fuel ratio must be set with a margin below the limit value to account for variations and aging, leaving potential efficiency improvement unused
Solution Approach 1:
The patent implements feedback control by detecting the actual air-fuel ratio using an air-fuel ratio sensor and comparing it with the target value. The ECU then adjusts the EGR valve opening degree based on the deviation detected, creating a closed-loop control system that maintains reliable combustion while operating near the dilution limit.
Solution Approach 2:
The patent dynamically adjusts the EGR valve opening degree in real-time based on actual combustion conditions and detected air-fuel ratio deviations. This dynamic control allows the system to operate near the dilution limit while adapting to variations and aging, thereby reducing fuel consumption without sacrificing combustion stability.
2Reliability
If the air-fuel ratio is set with a margin below the limit value to account for variations and aging, then combustion stability is maintained, but fuel consumption efficiency cannot be fully optimized
Solution Approach 1:
The feedback control mechanism continuously monitors the air-fuel ratio and adjusts the EGR valve opening to maintain optimal combustion. This allows the system to operate near the dilution limit with full efficiency while the feedback ensures combustion stability by correcting deviations caused by variations and aging.
Solution Approach 2:
The control system performs self-adjustment by automatically modifying the EGR valve opening based on detected combustion conditions. This self-service capability enables the engine to maintain optimal efficiency and stability without requiring manual intervention or conservative fixed settings.
3Loss of energy
If the EGR valve opening is increased to enhance dilution combustion, then fuel consumption is reduced, but the air-fuel ratio may deviate from the target value affecting combustion consistency
Solution Approach 1:
The feedback control system uses the air-fuel ratio sensor to detect deviations from the target value caused by EGR valve opening changes. The ECU then adjusts the EGR valve opening degree to compensate for these deviations, maintaining precise air-fuel ratio control even while operating at high dilution levels for reduced fuel consumption.
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
The solution enables the internal combustion engine to operate at a dilution level close to its limit, reducing fuel consumption and improving efficiency by adjusting the dilution based on real-time combustion state changes.
Implementation Method 1
a combustion method utilizing an exhaust gas recirculation (EGR) gas in which a part of a combustion gas is returned to an intake side to dilute a mixture of the fuel and the air
Implementation Method 2
lean combustion in which a ratio of a fuel and the air is lean compared with a stoichiometric mixture ratio (theoretical mixture ratio)
Data Source
AI summary
Provided is a control device for an internal combustion engine capable of realizing an operation of the internal combustion engine in a state in which a dilution is close to a limit. A processor (CPU 23a) of a control device for an internal combustion engine calculates a change amount of a parameter (for example, a combustion center position) indicating a combustion state of the internal combustion engine (combustion center change amount calculation unit 32). The processor (CPU 23a) corrects an operation amount of an actuator (for example, an EGR valve) that adjusts a dilution of an air-fuel mixture according to a difference between the change amount of the parameter indicating the combustion state and a target value of the change amount, and brings the change amount close to the target value (actuator operation amount correction unit 33).