Dual-Fuel Engine Injection Coupling for Reliable Mode Switching
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Solution Overview
Problem
There is a need for a novel dual-fuel internal combustion engine with a simple design that can efficiently operate using both liquid fuels, where one fuel is ignitable and the other is inert, and requires a seamless transition between operating modes.
Innovation Solution
A dual-fuel internal combustion engine design featuring a main injection system and a pilot injection system, where the first ignitable liquid fuel serves as both an ignition source and a working/barrier fluid in the second operating mode, utilizing a coupling mechanism between the systems to facilitate fuel supply and pressure control through a branch line with a pressure reducer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate sealing and lubricating oil systems are provided for dual-fuel operation, then the engine can reliably switch between fuel modes, but the device complexity increases
Solution Approach 1:
The patent combines the sealing and lubricating functions into a single oil system that serves both diesel and gas operating modes. The same lubricating oil is used for sealing the fuel injector valves and lubricating moving parts regardless of which fuel is being burned, eliminating the need for separate oil systems for each fuel type.
Solution Approach 2:
The lubricating oil system is designed to perform multiple functions universally across different operating modes. The oil serves as both a sealing medium for the injector valves and a lubricant for mechanical components, and this universal system works for both diesel injection mode and gas injection mode operations.
2Manufacturing precision
If dual-fuel fuel injectors with separate fuel pumps are used for each fuel, then precise fuel delivery is achieved, but the device complexity increases
Solution Approach 1:
The patent merges the fuel delivery function into a single fuel pump that can deliver both diesel fuel and gas fuel to the respective injectors. Instead of having separate pumps for each fuel type, one pump system handles both fuels by switching between them based on the operating mode.
Solution Approach 2:
The fuel pump system is designed to dynamically switch between delivering diesel fuel and gas fuel based on the current operating mode. The pump adapts its operation to handle the different properties of the two fuels, maintaining precise delivery regardless of which fuel is being used.
3Adaptability or versatility
If the engine design supports both liquid fuels with different ignition properties, then fuel versatility is improved, but the control system complexity increases
Solution Approach 1:
The injection system is designed with dynamic control capabilities that adapt to different fuel types and operating modes. The system can switch between diesel injection mode (where diesel is the main fuel) and gas injection mode (where gas is the main fuel and diesel is used as pilot fuel), adjusting injection timing, duration, and pressure based on the current mode.
Solution Approach 2:
The injection system is segmented into distinct control pathways for diesel and gas fuels. There are separate injection systems for each fuel type, but they are coordinated through a unified control strategy that manages the complexity by dividing the control functions while maintaining overall system integration.
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
Enables efficient operation in both modes with a simplified design, ensuring reliable ignition and sealing of valves, while maintaining operational efficiency and reducing complexity.
Implementation Method 1
the first liquid fuel serving as the working fluid and/or barrier fluid in the respective main injector. This working fluid or barrier fluid serves to seal and actuate the valves of the respective main injector
Implementation Method 2
The first liquid fuel serves to ignite the second liquid fuel in the second operating mode
Data Source
Figure 1
Figure 2
AI summary
Dual-fuel internal combustion engine, with cylinders (12) in which a first liquid fuel can be combusted in a first operating mode and a second liquid fuel in a second operating mode, with a main injection system comprising at least one main injector (16) per cylinder (12), through which the first liquid fuel, which is relatively ignitable, can be supplied to the cylinders (12) in the first operating mode, and through which the second liquid fuel, which is relatively inignitable, can be supplied to the cylinders (12) in the second operating mode, and with a pilot injection system comprising at least one pilot injector (23) per cylinder (12), through which the first liquid fuel can be supplied to the cylinders (12) of the internal combustion engine in the second operating mode for the ignition of the second liquid fuel, wherein the main injection system and the pilot injection system are coupled in such a manner,that in the second operating mode, starting from the pilot injection system, the first liquid fuel can be supplied to the respective main injector (16) of the main injection system as working fluid and/or as barrier fluid.