Hydrogen Combustion Engine Dynamic Air Ratio Control
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Solution Overview
Problem
Hydrogen combustion engines face challenges in reducing nitrogen oxide emissions, particularly in part-load operations where throttling losses occur, and in achieving efficient power density due to varying combustion air ratios, which also lead to greenhouse gas emissions issues.
Innovation Solution
A method for operating a hydrogen combustion engine by adjusting the combustion air ratio dynamically between λ≤1 and λ≥1.3, utilizing internal exhaust gas recirculation to manage torque demand and reduce NOX emissions, by altering the EGR fraction and fuel-air mixture, allowing for jerk-free transitions between operating states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the combustion air ratio is increased to λ≥2 to reduce nitrogen oxide emissions, then nitrogen oxide emissions are reduced, but the power density of the internal combustion engine is reduced to half of that at λ=1
Solution Approach 1:
The patent applies dynamic switching between different combustion air ratios (λ≤1 for high power demand and λ≥2 for low power demand) based on real-time torque requirements. This dynamic adaptation allows the engine to optimize between power output and emissions reduction, avoiding the static compromise of operating at a single combustion air ratio.
Solution Approach 2:
The patent changes the combustion air ratio parameter dynamically between two distinct ranges (λ≤1 and λ≥2) depending on operating conditions. This parameter switching enables the engine to achieve both high power density when needed and low nitrogen oxide emissions when power demand is lower, resolving the contradiction between these two performance aspects.
2Stability of the object's composition
If the combustion air ratio is set to λ=1 to achieve stoichiometric conditions and stabilize combustion, then combustion stability is improved, but nitrogen oxide emissions increase requiring exhaust-gas aftertreatment
Solution Approach 1:
Instead of maintaining a static combustion air ratio of λ=1, the patent dynamically switches between λ≤1 and λ≥2 based on torque demand. This dynamic approach allows the engine to achieve combustion stability when needed while reducing nitrogen oxide emissions during low-power operation, eliminating the need for continuous exhaust-gas aftertreatment.
Solution Approach 2:
The patent employs periodic switching between different combustion modes (rich/stoichiometric and lean) based on varying torque demands. This periodic action between different combustion air ratios allows the engine to alternate between stability-optimized and emissions-optimized operation, achieving both goals at different times rather than compromising either continuously.
3Ease of operation
If throttling is used to control engine load in part-load operation, then engine load control is achieved, but throttling losses reduce energy efficiency
Solution Approach 1:
The patent changes the combustion air ratio parameter to λ≥2 in part-load operation, which eliminates the need for throttling to control engine load. This parameter change allows the engine to maintain adequate torque while operating with excess air, thereby avoiding throttling losses and improving energy efficiency in part-load conditions.
4Power
If the fuel injection amount is increased to meet higher torque demand, then power output is increased, but nitrogen oxide emissions increase
Solution Approach 1:
The patent dynamically switches to λ≤1 combustion air ratio when higher torque demand is detected, allowing increased fuel injection without excessive nitrogen oxide emissions. This dynamic switching enables the engine to meet high power demands while managing emissions through the alternative combustion mode, rather than continuously increasing emissions with fuel injection.
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 effectively reduces nitrogen oxide emissions, complies with stringent emission regulations, and maintains engine power efficiency by optimizing combustion conditions, thereby enhancing the operational effectiveness of hydrogen combustion engines.
Implementation Method 1
it is possible in this way to achieve a reduction of the nitrogen oxide emissions in that, for the exhaust-gas aftertreatment, a conventional 3-way catalytic converter can be used for the reduction of the nitrogen oxides and, furthermore, less oxygen is available for the formation of nitrogen oxides during the combustion process. Furthermore, a reduced combustion temperature and a reduced flame speed contribute to the reduction of the formation of nitrogen oxide.
Implementation Method 2
a conventional 3-way catalytic converter can be used for the reduction of the nitrogen oxides
Implementation Method 3
hydrogen-containing fuel is burned
Data Source
AI summary
Methods and systems are provided for a hydrogen combustion engine. In one example, a method may include operating the hydrogen combustion engine at one of two combustion air ratios, wherein a combustion air ratio between the two is avoided via adjusting one or more operating parameters.