Multi-Fuel Engine Injection for Ammonia Combustion
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Solution Overview
Problem
Internal combustion engines face challenges in achieving efficient combustion of fuels with high heat of vaporization and low flame speed, leading to poor combustion conditions, particularly when using energy-dense fuels like diesel and ammonia, which require innovative methods to enhance their combustibility and emissions control.
Innovation Solution
The method involves injecting a first fuel directly into the combustion chamber and a second fuel, such as ammonia, into the exhaust port or EGR passage, with adjusted exhaust valve timing to increase exhaust gas re-ingestion and recirculation, promoting better mixing and vaporization of ammonia by utilizing hot exhaust gases, and controlling injection timing and amounts based on desired substitution rates and cooling requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If energy-dense fuels like diesel and ammonia are used, then fuel energy density is improved, but combustion conditions deteriorate due to high heat of vaporization and low flame speed
Solution Approach 1:
The fuel injection system is segmented into multiple injection locations (direct injection into combustion chamber, exhaust port injection, and EGR passage injection) to deliver different fuels at different stages of the combustion cycle, allowing optimized combustion conditions for each fuel type while maintaining high energy density
Solution Approach 2:
Exhaust gas recirculation is used to pre-heat and prepare the combustion chamber environment before the actual combustion event, creating favorable conditions for fuels with high heat of vaporization and low flame speed by establishing optimal temperature and composition ahead of time
2Temperature
If exhaust valve timing is adjusted to increase exhaust gas re-ingestion, then EGR cooling is improved, but combustion efficiency may deteriorate
Solution Approach 1:
Exhaust valve timing is dynamically adjusted based on operating conditions to optimize the balance between EGR cooling benefits and combustion efficiency, allowing the system to adapt to different fuel types and load conditions in real-time
Solution Approach 2:
Different regions of the combustion chamber are created with different thermal and compositional characteristics through strategic fuel injection locations, allowing localized optimization where EGR cooling is needed most while preserving overall combustion efficiency
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 enhances the combustibility of ammonia and reduces emissions by optimizing fuel injection strategies and exhaust gas recirculation, improving engine performance and reducing the need for additional cooling systems, thereby increasing system longevity and efficiency.
Implementation Method 1
promoting better mixing and vaporization of ammonia by utilizing hot exhaust gases
Implementation Method 2
exhaust gas recirculation, promoting better mixing and vaporization of ammonia by utilizing hot exhaust gases
Implementation Method 3
combusting the first and second fuels together in the combustion chamber
Data Source
AI summary
Methods and systems are provided for adjusting a location of a fuel injection in response to a substitution rate and a desired EGR flow. In one example, a method may include injecting a first fuel to a combustion chamber via a direct injector positioned to inject directly into the combustion chamber, injecting a second, different, fuel to the combustion chamber via an exhaust port injector positioned to inject toward an exhaust valve of the combustion chamber, and combusting the first and second fuels together in the combustion chamber.