Direct Fuel Injector Tip Vaporization Prevention
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Solution Overview
Problem
Direct fuel injectors in engines operating with both port and direct fuel injectors face durability issues due to high temperatures leading to fuel vaporization and deposit formation, which can be exacerbated by periodic cooling methods that deplete fuel supplies and fail to prevent vapor space formation.
Innovation Solution
Increasing the rail pressure of the fuel rail coupled to the direct fuel injector when its tip temperature exceeds a threshold, either by operating a high-pressure fuel pump to maintain liquid fuel or by injecting fuel specifically during high-temperature conditions, thereby preventing vapor space formation and fuel distillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the direct fuel injector is periodically operated to cool the injector tip, then the injector tip temperature is reduced, but the fuel supply is depleted and not available when needed
Solution Approach 1:
The system performs preliminary cooling of the direct fuel injector tip by injecting fuel through it before the injector is needed for normal operation. This preliminary action reduces the injector tip temperature to prevent fuel vaporization and maintain proper fuel delivery when the injector is activated, while the control system manages fuel supply to ensure adequate fuel remains in the tank.
2Loss of energy
If the direct fuel injector is not operated for extended periods, then fuel economy is improved, but fuel vaporization occurs within the injector leading to deposits and reduced durability
Solution Approach 1:
The control system implements periodic operation of the direct fuel injector during periods when the engine is operating on port fuel injection only. The injector is activated at scheduled intervals to inject a small amount of fuel that condenses and drains through the injector, thereby cooling the injector tip and preventing fuel vaporization and deposit formation, while maintaining overall fuel economy by not operating the injector continuously.
3Temperature
If periodic fuel injection is used to cool the direct injector, then injector tip temperature is reduced, but vapor space formation is not sufficiently prevented
Solution Approach 1:
The system changes the operating parameters of the direct fuel injector by operating it at lower duty cycles and shorter durations compared to continuous operation. The control system adjusts the injection timing, duration, and frequency to optimize cooling effectiveness while preventing vapor space formation in the fuel rail and injector, thereby maintaining proper fuel delivery without requiring full injector 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 method effectively prevents fuel distillation and maintains injector durability by ensuring the fuel remains in a liquid state, even during prolonged operation with only the port fuel injector, while optimizing engine emissions and fuel economy.
Implementation Method 1
the increased temperature at the direct injector may lead to the vaporization of fuel within the direct injector
Implementation Method 2
increasing a rail pressure of a fuel rail coupled to the second injector in response to a temperature increase of a tip of the second injector
Implementation Method 3
The direct injectors may be cooled by periodically injecting fuel from the direct fuel injectors during operation of the vehicle
Data Source
AI summary
A method, comprising: during engine cylinder operation with fuel from a first injector and not a second injector: increasing a rail pressure of a fuel rail coupled to the second injector in response to a temperature increase of a tip of the second injector. In this way, by raising the rail pressure of a fuel rail coupled to the second injector in response to a temperature increase of a tip of the second injector, the method may be utilized to prevent a vapor space from forming within the tip of the second injector which is exposed to the heat of combustion within the engine cylinder. By preventing a vapor space from forming, the method may be used to prevent fuel distillation in the tip of the second injector during periods where the engine cylinder is operating with fuel from a first injector and not the second injector.