Internal Combustion Engine Torque Build-Up via Staged Hydrogen Injection
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Solution Overview
Problem
Internal combustion engines face a conflict between rapid torque build-up and low nitrogen oxide emissions, as increasing fuel to enhance torque leads to higher nitrogen oxide emissions, particularly in hydrogen-powered engines.
Innovation Solution
A method for operating hydrogen-powered internal combustion engines involves lean burning a first quantity of fuel during the expansion cycle, followed by cooling the combustion chamber and supplying a second quantity of hydrogen during the expansion stroke, which is burned to increase torque and exhaust gas enthalpy without exceeding nitrogen oxide emission targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the amount of fuel is increased to increase torque, then torque and exhaust gas enthalpy increase, but nitrogen oxide emissions increase significantly
Solution Approach 1:
The fuel injection is divided into multiple separate injection events during the expansion stroke, with different fuel quantities injected at different times. This segmentation allows the total fuel amount to be distributed, enabling torque increase while controlling peak temperatures and nitrogen oxide formation by avoiding simultaneous combustion of all fuel
Solution Approach 2:
A first quantity of fuel is injected and combusted before the second quantity of fuel. This preliminary action creates a staged combustion process where the first combustion event prepares the combustion chamber conditions (temperature, pressure) for the second fuel injection, allowing efficient energy release while managing peak temperatures to limit nitrogen oxide emissions
2Productivity
If the air-fuel mixture is enriched during load build-up to increase torque rapidly, then torque build-up speed increases, but nitrogen oxide emissions increase
Solution Approach 1:
Fuel injection occurs in periodic pulses during the expansion stroke rather than as a continuous enriched mixture. The periodic injection events (first quantity followed by second quantity) create controlled combustion phases that rapidly release energy for fast torque build-up while the lean overall air-fuel ratio prevents excessive nitrogen oxide formation
3Object-generated harmful factors
If the fuel quantity is limited to maintain low nitrogen oxide emissions, then nitrogen oxide emissions remain low, but torque and exhaust gas enthalpy increase slowly
Solution Approach 1:
The combustion process parameters are changed by injecting fuel during the expansion stroke rather than before compression. This timing change allows the combustion to occur when the cylinder volume is larger and pressure is lower, reducing peak temperatures and nitrogen oxide formation while still extracting sufficient energy to increase exhaust gas enthalpy and torque
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 a rapid increase in torque and exhaust gas enthalpy while maintaining low nitrogen oxide emissions by carefully managing the fuel quantities and combustion timing, overcoming turbo lag and achieving desired boost pressure.
Implementation Method 1
lean burning of a first quantity of fuel, in particular hydrogen and/or natural gas, during an expansion stroke
Implementation Method 2
cooling of the main combustion chamber during the expansion stroke after the lean combustion
Implementation Method 3
combustion of the second quantity of fuel in the main combustion chamber during the expansion stroke
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a method for operating an internal combustion engine (10). The method has the steps of lean burning a first fuel quantity during an expansion stroke of the internal combustion engine (10) in a main combustion chamber (16) of the internal combustion engine (10), cooling the main combustion chamber (16) during the expansion stroke following the lean burning process, supplying a second fuel quantity of hydrogen to the main combustion chamber (16) during the expansion stroke after the cooling process, and combusting the second fuel quantity in the main combustion chamber (16) during the expansion stroke. The method allows a rapid torque build-up with low nitrogen oxide emissions.