Cylinder-Specific Engine Water Injection for Combustion Stability
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Solution Overview
Problem
In internal combustion engines with an EGR passage and water injection valves, the condensation of moisture in the EGR gas leads to varying amounts of water entering each cylinder, causing inconsistent combustion states due to differing water amounts across cylinders.
Innovation Solution
A controller and storage medium that use processing circuitry to calculate and control water injection amounts based on operation parameters, adjusting water injection valves to ensure a uniform water amount in each cylinder by accounting for varying EGR water amounts using dedicated maps and reference information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an EGR cooler is arranged in the EGR passage to cool the EGR gas, then the EGR gas temperature is reduced, but condensation of moisture occurs in the EGR passage causing varying water amounts in different cylinders
Solution Approach 1:
The patent divides the water injection control into cylinder-specific segments by providing separate water injection valves for each cylinder and storing dedicated map information for each cylinder in the storage unit. This allows independent control of water injection amounts for each cylinder based on its specific EGR water amount, thereby resolving the uniformity issue caused by condensation variations across cylinders
Solution Approach 2:
The patent changes the water injection amount parameter for each cylinder based on operation parameters and cylinder-specific EGR water amounts stored in map information. By dynamically adjusting the water injection amount parameter according to actual condensation conditions in each cylinder, the system maintains uniform total water amounts (EGR water + injected water) across all cylinders despite variations in EGR condensation
2Ease of operation
If the same amount of water is injected through each water injection valve, then the water injection system is simple to operate, but the total water amount in each cylinder varies due to different EGR water amounts
Solution Approach 1:
The system uses pre-stored map information for each cylinder that contains the relationship between operation parameters and EGR water amounts. The control unit automatically retrieves and applies the appropriate correction values from these maps based on current operation conditions, enabling the system to self-adjust water injection amounts without complex real-time measurements or manual intervention
Solution Approach 2:
The patent implements a feedback mechanism by storing map information that reflects the actual EGR water amounts for each cylinder under various operation conditions. The control unit uses this feedback information to calculate corrected water injection amounts, ensuring that the total water amount (EGR condensation + water injection) achieves the target value for each cylinder, thereby maintaining consistent combustion states
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 ensures a substantially uniform water distribution across cylinders, stabilizing combustion states and minimizing water consumption, particularly in engines using hydrogen gas and forced-induction devices.
Implementation Method 1
an EGR cooler arranged in the EGR passage and configured to cool the EGR gas
Implementation Method 2
an EGR cooler for cooling the EGR gas may be arranged in the EGR passage. Such a structure may cause condensation of moisture contained in the EGR gas in the EGR passage
Data Source
AI summary
An amount of condensed water generated in an EGR passage and flowing into one cylinder in a unit period is referred to as an EGR water amount. Memory stores information indicating a corresponding relationship between a parameter related to an operation state of an internal combustion engine and a parameter related to the EGR water amount for each cylinder. When the internal combustion engine is operating, a controller acquires a value obtained by subtracting the EGR water amount of each cylinder from a reference water amount that corresponds to the operation state of the internal combustion engine as a target water injection amount of each cylinder based on the information. The controller controls each water injection valve so that the water injection valve injects the target water injection amount of each cylinder.