Engine Water Injection Controller Pressure Dynamics
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Solution Overview
Problem
Existing internal combustion engine water injection systems face challenges in ensuring complete evaporation of water in the cylinders due to the formation of thick liquid films in the intake passage, which can lead to reduced water supply to the cylinders.
Innovation Solution
A controller for an internal combustion engine that executes a first injection process when the intake valve is open and a second injection process when the intake valve is closed, with the pressure adjustment device setting a higher water pressure for the second injection process than for the first injection process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If water is injected during the closed period of the intake valve to ensure sufficient water supply, then the water amount supplied to cylinders is improved, but thick liquid film forms on the intake passage wall surface reducing evaporation efficiency
Solution Approach 1:
The system performs preliminary water injection during the closed period of the intake valve to pre-supply water to the intake passage. This preliminary action ensures that sufficient water is available in the intake passage before the valve opens, while the high pressure during this phase promotes atomization and prevents excessive film formation.
Solution Approach 2:
The water injection system dynamically adjusts the injection pressure based on the intake valve state. During the closed period, high pressure is applied to inject water effectively into the intake passage. When the valve opens, the pressure is reduced to prevent excessive film formation on the cylinder walls, thus balancing water supply quantity with evaporation efficiency.
2Reliability
If water injection pressure is increased to improve water delivery during closed period, then water supply reliability is improved, but risk of liquid film accumulation and incomplete evaporation increases
Solution Approach 1:
The injection pressure is dynamically adjusted based on the intake valve state. During the closed period, high pressure is maintained to ensure reliable water delivery to the intake passage. When the valve opens, the pressure is immediately reduced to prevent liquid film accumulation on the cylinder walls, thus eliminating the harmful effect while maintaining supply reliability.
Solution Approach 2:
The water injection system operates in periodic cycles synchronized with the intake valve. During the closed period, high-pressure injection occurs to deliver water reliably. During the open period, low-pressure injection prevents harmful liquid film formation. This periodic variation in pressure ensures both reliability and prevents harmful effects.
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 that the target amount of water is injected into the cylinders, preventing the formation of large water droplets and allowing for effective evaporation, thereby improving engine cooling and performance.
Implementation Method 1
a water injection valve configured to inject water into the intake passage
Implementation Method 2
The water injected by the water injection valves flows into the corresponding cylinders through the intake passage and evaporates in the cylinders. When the water evaporates, the heat of vaporization lowers the temperatures in the cylinders.
Implementation Method 3
When the water evaporates, the heat of vaporization lowers the temperatures in the cylinders.
Implementation Method 4
a pressure adjustment device configured to adjust pressure of water supplied to the water injection valve
Data Source
Figure 1~2
Figure 3
Figure 4~6
AI summary
A controller for an internal combustion engine is configured to execute a first injection process that causes a water injection valve to inject water when an intake valve is open and a second injection process that causes the water injection valve to inject water when the intake valve is closed. The controller is further configured to set a pressure of the water supplied to the water injection valve to be higher in the second injection process than in the first injection process.