Hydrogen-Mixed Engine Control for NOx Reduction Without H2 Sensors
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Solution Overview
Problem
Conventional engine devices driven by hydrogen-mixed fuel gas struggle to reduce nitrogen oxide emissions and maintain 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 exhaust temperature and air-fuel mixture pressure to adjust the excess air ratio and ignition timing, reducing nitrogen oxide emissions without the need for 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 due to inability to respond to hydrogen mixing ratio variations
Solution Approach 1:
The patent implements feedback control by monitoring exhaust temperature and using it to adjust ignition timing and air-fuel ratio. The exhaust temperature sensor provides continuous feedback about combustion conditions, allowing the control unit to dynamically adjust ignition parameters and fuel supply to maintain optimal combustion despite hydrogen mixing ratio variations, thereby reducing nitrogen oxide emissions without requiring complex hydrogen sensors.
Solution Approach 2:
The patent changes combustion parameters (ignition timing and air-fuel ratio) based on exhaust temperature measurements. By dynamically adjusting these parameters in response to temperature variations caused by hydrogen content changes, the system optimizes combustion efficiency 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 combustion control accuracy improves, but device cost increases and complexity increases
Solution Approach 1:
The patent uses exhaust temperature as an intermediary parameter to indirectly measure hydrogen mixing ratio effects. Instead of directly sensing hydrogen concentration or NOx levels, the system measures exhaust temperature which reflects the combined effect of hydrogen content on combustion, and uses this intermediary measurement to adjust control parameters appropriately.
Solution Approach 2:
The patent replaces expensive chemical sensors (hydrogen sensors, NOx sensors) with a simpler thermal measurement system using exhaust temperature sensors. This substitution uses thermal physics principles to infer combustion conditions and hydrogen content effects, achieving comparable control accuracy with significantly reduced system complexity and cost.
3Object-generated harmful factors
If fuel supply and ignition parameters are adjusted to reduce nitrogen oxide emissions, then emission compliance improves, but fuel efficiency may decrease
Solution Approach 1:
The patent employs dynamic adjustment of ignition timing and air-fuel ratio based on real-time exhaust temperature measurements. Rather than using fixed conservative settings that would guarantee emission compliance but reduce efficiency, the system continuously adapts parameters to optimize both emission control and fuel efficiency under varying operating conditions and hydrogen mixing ratios.
Solution Approach 2:
The patent dynamically changes ignition timing and air-fuel ratio parameters based on exhaust temperature feedback. By adjusting these parameters in real-time according to actual combustion conditions, the system maintains nitrogen oxide emissions at acceptable levels while maximizing fuel efficiency, avoiding the need for overly conservative fixed parameter settings.
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, maintaining fuel efficiency and compliance with emission regulations.
Implementation Method 1
combustion of the fuel gas generates exhaust gas containing nitrogen oxides (NOx)
Implementation Method 2
the fuel gas is mixed with air and supplied to the engine as an air-fuel mixture
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
[ABSTRACT] [Problem] Provided is an engine device capable of reducing the amount of nitrogen oxide emissions to a target value regardless of the hydrogen mixing ratio in fuel gas, without the need for expensive sensors. [Solution] An engine device 1 that is driven by hydrogen-mixed fuel gas includes: an engine 2; and a control unit 8 that controls, based on an excess air ratio of an air-fuel mixture of air and the fuel gas supplied to the engine 2, and an exhaust temperature of exhaust gas from the engine 2, the excess air ratio and/or an ignition parameter of the engine 2 in such a manner that nitrogen oxides in the exhaust gas are reduced.