Dual Fuel Engine Mode Selection via Injection Control
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Solution Overview
Problem
Dual fuel internal combustion engines of the diesel-type lack a method to efficiently switch between different operation modes, such as homogeneous ignition and pre-mixed flame propagation combustion, which limits their operational flexibility and efficiency.
Innovation Solution
The method involves adjusting the amount and timing of the second fuel injection in the combustion chamber to control temperature and pressure, allowing selection between homogeneous ignition and pre-mixed flame propagation combustion modes by varying the amount of second fuel injected, and optionally using subsequent liquid injections to enhance mixing and turbulence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the amount of second fuel injected is increased to initiate homogeneous combustion, then combustion efficiency is improved, but the ability to switch between operation modes is reduced
Solution Approach 1:
The injection system dynamically adjusts the amount and timing of second fuel injection based on desired operation mode. The controller varies injection quantity and timing parameters to switch between homogeneous combustion and pre-mixed flame propagation modes, enabling the system to adapt to different operational requirements while maintaining combustion efficiency in each mode.
Solution Approach 2:
The invention changes key parameters including second fuel injection amount, injection timing, and compression ratio to achieve different operation modes. By adjusting these parameters, the system can transition between homogeneous combustion (higher injection amount) and pre-mixed flame propagation (lower injection amount with optimized timing), thus maintaining versatility while optimizing for each mode.
2Adaptability or versatility
If the second fuel injection timing is advanced to control combustion chamber temperature, then operation mode selection is enabled, but combustion robustness may be compromised
Solution Approach 1:
The system employs feedback control where sensors monitor combustion chamber conditions such as temperature, pressure, and exhaust gas composition. The controller uses this feedback information to adjust second fuel injection timing and amount, ensuring that combustion remains robust while enabling mode switching. The feedback mechanism allows real-time optimization of injection parameters to maintain reliable combustion across different operation modes.
Solution Approach 2:
The injection system uses periodic, controlled injection pulses of the second fuel at precisely timed intervals. By optimizing the periodic injection pattern and its timing relative to the compression stroke, the system achieves reliable auto-ignition and robust combustion while maintaining the ability to switch between operation modes through variation in the periodic action parameters.
3Productivity
If subsequent liquid injections are used to enhance mixing, then combustion efficiency is improved, but device complexity increases
Solution Approach 1:
The injection system is designed to perform multiple functions using the same hardware. The second fuel injection system serves both as the primary ignition initiator and as a means to enhance mixing through subsequent injection pulses. This multi-functionality allows the system to improve fuel efficiency through enhanced mixing without requiring separate dedicated mixing injection hardware, thus limiting the increase in device complexity.
Solution Approach 2:
The system uses periodic subsequent liquid injection pulses timed during the combustion process to enhance mixing of remaining fuel. These periodic injections create turbulence and improve homogeneity without requiring complex continuous injection systems. The simple periodic pulsed approach achieves enhanced mixing and improved fuel efficiency while keeping the injection system relatively simple.
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 enables seamless switching between operation modes, improving fuel efficiency, reducing emissions, and enhancing combustion robustness by controlling combustion chamber conditions and using feedback from sensors to optimize subsequent injections.
Implementation Method 1
performing a first injection of the second fuel into said combustion chamber to initiate auto-ignition of said second fuel
Implementation Method 2
compressing the charge containing the first fuel to conditions that allow auto-ignition of the second fuel
Implementation Method 3
compressing the charge containing the first fuel to conditions close to Homogeneous Charge Compression Ignition (HCCI) of said first fuel
Implementation Method 4
igniting said first fuel in said combustion chamber by injection and auto-ignition of a second fuel to thereby initiate conditions for pre-mixed flame propagation combustion
Data Source
Figure 1a~2c
Figure 3~4
Figure 5~6
AI summary
The present invention relates to a method of selecting between two operation modes in a dual fuel internal combustion engine of the diesel-type, comprising a combustion chamber being at least partly delimited by a piston, a first fuel supply for a first fuel, said first fuel supply being located in or at the combustion chamber and/or in or at an inlet port thereof, and a second fuel supply for a second fuel, - the engine having two different operation modes, both operation modes comprising the steps of: - pre-mixing said first fuel in said combustion chamber and/or in said inlet port, - compressing the charge containing the first fuel to conditions that allow auto-ignition of the second fuel, - performing a first injection of the second fuel into said combustion chamber to initiate auto-ignition of said second fuel, thereby initiating conditions for combustion of the fuel remaining in the combustion chamber after auto-ignition of the second fuel, wherein - said first operation mode is distinguished by homogeneous ignition and combustion of the remaining fuel, - said second operation mode is distinguished by pre-mixed flame propagation combustion of the remaining fuel, said method further comprising the step of: - adjusting the amount of the second fuel injected in said first injection of the second fuel, and/or the timing of said first injection of the second fuel, so as to control the combustion chamber temperature and pressure after auto-ignition of the second fuel such that selection between said first and second operation modes is achieved. The invention also relates to a dual fuel internal combustion engine of the diesel-type.