Hydrogen-Mixed Engine Control Using Exhaust Temperature Feedback
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Solution Overview
Problem
Conventional engine devices driven by hydrogen-mixed fuel gas struggle with increased nitrogen oxide emissions and decreased fuel efficiency due to variations in hydrogen mixing ratio, requiring expensive sensors for effective control.
Innovation Solution
An engine device that controls fuel supply and ignition parameters based on feed pressure and exhaust temperature to maintain optimal air-fuel ratio and ignition timing, reducing nitrogen oxide emissions without expensive sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional constant air-fuel ratio control is used in hydrogen-mixed fuel gas engines, then the control system remains simple, but nitrogen oxide emissions increase and fuel efficiency decreases
Solution Approach 1:
The patent implements feedback control by detecting exhaust temperature and using it to adjust ignition timing and air-fuel ratio. The control unit continuously monitors exhaust temperature and modifies ignition parameters based on the detected values, creating a closed-loop system that automatically adapts to hydrogen mixing ratio variations without requiring complex sensor systems.
Solution Approach 2:
The patent changes operational parameters (ignition timing and air-fuel ratio) based on exhaust temperature detection. By dynamically adjusting these parameters in response to temperature variations caused by different hydrogen mixing ratios, the system maintains optimal combustion characteristics and reduces nitrogen oxide emissions without requiring direct hydrogen concentration measurement.
2Measurement precision
If expensive sensors such as hydrogen sensor and NOx sensor are added to track hydrogen mixing ratio, then control accuracy improves, but device complexity and cost increase
Solution Approach 1:
The patent uses exhaust temperature as an intermediary parameter to indirectly measure hydrogen mixing ratio. Instead of directly detecting hydrogen concentration or NOx levels with expensive sensors, the system measures exhaust temperature which reflects the combustion characteristics influenced by hydrogen content, and uses this information to adjust control parameters accordingly.
Solution Approach 2:
The patent replaces the need for complex chemical sensors (hydrogen sensors, NOx sensors) with a simpler thermal measurement system. By substituting direct chemical composition measurement with temperature-based indirect measurement, the system achieves comparable control accuracy with significantly reduced device complexity and cost.
3Use of energy by moving object
If air-fuel ratio is maintained at theoretical ratio for hydrocarbon-based fuel gas, then combustion efficiency is optimized, but nitrogen oxide emissions increase when hydrogen mixing ratio varies
Solution Approach 1:
The patent transitions from static theoretical air-fuel ratio control to dynamic control that adapts to changing combustion conditions. By continuously adjusting ignition timing and air-fuel ratio based on real-time exhaust temperature measurements, the system maintains optimal combustion efficiency across varying hydrogen mixing ratios while preventing excessive nitrogen oxide formation.
Solution Approach 2:
The patent applies preliminary anti-action by adjusting ignition timing and air-fuel ratio in advance based on exhaust temperature trends, preventing nitrogen oxide formation before it occurs. The control unit proactively modifies combustion parameters to counteract the tendency toward excessive NOx formation that would result from maintaining fixed theoretical air-fuel ratio under varying hydrogen content conditions.
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
The engine device effectively reduces nitrogen oxide emissions to a target value regardless of hydrogen mixing ratio, improving fuel efficiency and meeting emission regulations.
Implementation Method 1
combustion of the fuel gas generates exhaust gas containing nitrogen oxides (NOx)
Data Source
AI summary
An engine device that is driven by hydrogen-mixed fuel gas includes: an engine; and a control unit that controls, based on an excess air ratio of an air-fuel mixture of air and the fuel gas supplied to the engine, and an exhaust temperature of exhaust gas from the engine, the excess air ratio and/or an ignition parameter of the engine in such a manner that nitrogen oxides in the exhaust gas are reduced.