Engine Controller Water Injection Timing for Intake Port Wall Management
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Solution Overview
Problem
In engines with water injection valves, water collects on the intake port walls, leading to large water droplets flowing into the cylinder, which do not evaporate and can cause engine oil emulsification or increased crankcase pressure.
Innovation Solution
A controller is implemented to manage water injection in engines by selectively executing synchronous and asynchronous injections, where synchronous injection occurs during valve opening and asynchronous injection during valve closing, with a switching process to alternate between intake ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water injection is repeatedly executed, then cooling effect is improved, but water collection on intake port walls increases leading to large water droplets
Solution Approach 1:
The controller executes asynchronous water injection during the intake valve closing period before the valve fully closes, preventing water from collecting on the intake port walls by injecting water at a timing when the valve is closing, thereby eliminating the technical contradiction between cooling effect and water collection
2Quantity of substance
If asynchronous injection is used, then water collection on intake port walls is reduced, but injection timing control complexity increases
Solution Approach 1:
The controller alternates between synchronous injection during valve opening period and asynchronous injection during valve closing period in a periodic manner, switching the injection timing based on the intake valve position cycle, thereby reducing water collection while maintaining manageable control complexity through regular periodic operation
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 restricts water collection on intake port walls, preventing large water droplets from entering the cylinder and reducing the risk of engine oil clouding and crankcase pressure increase.
Implementation Method 1
a water injection valve for injecting water into intake air
Implementation Method 2
the water droplets evaporate in the cylinder if the water droplets are small
Implementation Method 3
some of the water injected into the intake air collects on the wall surface of the intake port
Data Source
Figure 1~2
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AI summary
An engine includes water injection valves that inject water to intake ports connected to a cylinder. A controller for the engine is configured to selectively execute, for each of the intake ports, a synchronous injection that causes the water injection valve to inject water only during a valve opening period of the intake valve and an asynchronous injection that causes the water injection valve to inject water during a valve closing period of the intake valve. The controller is configured to perform, when executing a synchronous/asynchronous concurrent injection in which the intake ports includes an intake port in which the synchronous injection is executed and an intake port in which the asynchronous injection is executed, a switching process of switching the intake port in which the asynchronous injection is executed.