Multi-Fuel Engine Combustion Control for Carbon-Free Fuels
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Solution Overview
Problem
Internal combustion engines face challenges in achieving optimal combustion conditions when switching between single-fuel and multi-fuel combustion, particularly due to fuels with high heat of vaporization and low flame speed, leading to poor combustion efficiency and emissions.
Innovation Solution
The method involves adjusting the temperature reducing mass of the combustion mixture by increasing the amount of air, exhaust gas recirculation (EGR), and water, and strategically incorporating fuels like ammonia and hydrogen to enhance combustion efficiency and reduce cylinder temperature, while also adjusting ignition timing and EGR flow rates to promote better fuel mixing and ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If fuels with high heat of vaporization and low flame speed are used, then carbon-free fuel substitution ratio is increased, but combustion efficiency deteriorates
Solution Approach 1:
The patent adjusts combustion parameters including ignition timing advancement, compression ratio optimization, and intake temperature reduction to compensate for the poor combustion characteristics of carbon-free fuels like ammonia and hydrogen, thereby maintaining combustion efficiency while increasing their substitution ratio
Solution Approach 2:
The patent uses hydrocarbon fuels as pilot fuels or intermediaries to initiate and sustain combustion of carbon-free fuels, which have difficult ignition characteristics, thereby enabling higher substitution ratios without sacrificing combustion efficiency
2Object-generated harmful factors
If carbon-free fuels with low flame speed are used, then emissions are reduced, but combustion completeness deteriorates
Solution Approach 1:
The patent optimizes combustion chamber temperature, pressure, and residence time parameters to ensure complete combustion of carbon-free fuels, preventing incomplete combustion products while maintaining low emission levels
Solution Approach 2:
The patent employs pre-combustion heating, exhaust gas recirculation control, and intake air heating to prepare optimal combustion conditions before carbon-free fuel combustion, ensuring complete combustion and preventing harmful incomplete combustion products
3Productivity
If cylinder temperature is reduced to improve combustion stability, then combustion efficiency is improved, but ignition difficulty increases
Solution Approach 1:
The patent uses pre-combustion heating of the intake charge and compression heating to raise the temperature of the combustion mixture before ignition, ensuring reliable ignition of carbon-free fuels while maintaining controlled combustion temperatures for stability
4Reliability
If hydrocarbon pilot fuel is used to enable carbon-free fuel combustion, then combustion reliability is improved, but carbon emissions increase
Solution Approach 1:
The patent uses minimal amounts of hydrocarbon pilot fuel just sufficient to initiate and sustain combustion of carbon-free fuels, thereby maintaining combustion reliability while minimizing carbon emissions from the pilot fuel itself
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 allows for improved combustion efficiency, reduced emissions, and increased use of carbon-free fuels, thereby enhancing engine performance and reducing carbon and NOx emissions across a range of operating conditions.
Implementation Method 1
increasing a temperature reducing mass of a combustion mixture... The temperature reducing mass may include air, exhaust gas recirculation (EGR), water
Implementation Method 2
The temperature reducing mass may include air, exhaust gas recirculation (EGR), water
Implementation Method 3
The multi-fuel combustion may include one or more of ammonia and hydrogen
Data Source
AI summary
Methods and systems are provided for a multi-fuel engine. In one example, a method includes increasing a temperature reducing mass of a combustion mixture during a transition to multi-fuel combustion from single-fuel combustion.