Spark Ignition Gas Engine Ignition Timing Control via Exhaust Temperature
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Solution Overview
Problem
Otto gas engines face challenges in maintaining efficient operation and controlling NOx emissions due to fluctuations in fuel gas composition, particularly with biogas, as existing methods rely on complex gas sensors or fail to account for age-related engine wear, leading to inefficiencies and potential engine knocking.
Innovation Solution
The method involves adjusting the ignition timing of the Otto gas engine based on the throttle position of a mixing arrangement component, in combination with exhaust gas temperature, to regulate the ignition point without using complex gas sensors, ensuring consistent efficiency and NOx emission levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex gas sensors are used to determine fuel gas composition, then measurement precision of combustion behavior is improved, but device complexity increases
Solution Approach 1:
The patent uses exhaust gas temperature as an intermediary parameter to indirectly determine fuel gas composition and combustion behavior. Instead of directly measuring fuel gas properties with complex sensors, the system measures the exhaust gas temperature which correlates with combustion characteristics, thereby simplifying the measurement system while maintaining adequate precision for control purposes
Solution Approach 2:
The patent replaces complex mechanical gas sensors with a thermal measurement approach using exhaust gas temperature sensors. This substitution eliminates the need for complex gas composition analysis hardware while providing sufficient information for ignition timing adjustment through the established correlation between temperature and combustion behavior
2Adaptability or versatility
If ignition timing is adjusted based on exhaust gas temperature, then adaptability to fuel gas composition variations is improved, but reliability decreases due to engine wear effects
Solution Approach 1:
The patent implements dynamic ignition timing adjustment that adapts to changing operating conditions including engine wear. The system continuously modifies ignition timing based on real-time exhaust gas temperature measurements and throttle position data, allowing the ignition system to dynamically compensate for both fuel gas composition variations and age-related engine changes, thereby maintaining reliability across the engine's service life
Solution Approach 2:
The patent employs feedback control by continuously monitoring exhaust gas temperature and throttle position, then using this information to adjust ignition timing in real-time. This closed-loop feedback mechanism ensures that ignition timing remains optimal despite variations in fuel gas composition or engine wear, as the system constantly adapts based on actual operating conditions rather than relying on fixed predetermined values
3Device complexity
If ignition timing is kept constant, then device complexity is reduced, but efficiency and NOx emission control deteriorate due to fuel gas composition fluctuations
Solution Approach 1:
The patent transitions from static to dynamic ignition timing control, adjusting the ignition point in real-time based on exhaust gas temperature and throttle position. This dynamic adaptation allows the system to maintain optimal efficiency and NOx emission control across varying fuel gas compositions without requiring overly complex sensor systems, as the control logic processes simple temperature and position data to determine appropriate timing adjustments
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 reliable operation of Otto gas engines with varying fuel gas compositions by correlating throttle position with ignition timing, maintaining constant efficiency and NOx emissions, even under conditions of engine wear, without the need for gas sensors.
Implementation Method 1
mixing air and fuel gas to form a combustion gas mixture
Implementation Method 2
mixing air and fuel gas to form a combustion gas mixture
Implementation Method 3
igniting the combustion gas mixture in one Combustion chamber with setting an ignition point
Implementation Method 4
burning of the combustion-gas mixture with discharge of exhaust gas
Implementation Method 5
detecting an exhaust gas temperature (T_AG) of the exhaust gas (4) in the exhaust gas duct (150)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a method for operating a spark ignition gas engine (100), preferably with fuel gas in the form of biogas by setting an ignition time (ZZP) of the spark ignition gas engine (100), comprising: mixing of air (2) and fuel gas (3) to form a combustible gas mixture (1) in a mixing arrangement (140), feeding in and igniting the combustible gas mixture (1) in the combustion chamber while setting an ignition time (ZZP) and burning the combustible gas mixture (1) while discharging exhaust gas (4) from the combustion chamber, further comprising the steps: detection of an exhaust gas temperature (T_AG) of the exhaust gas (4), predefining at least one reactor position (LRV) of a component of the mixing arrangement (140), setting the ignition time (ZZP) of the spark ignition gas engine (100) as a function of the exhaust gas temperature (T_AG) and the reactor position (LRV). The invention provides that the reactor position (LRV) is predefined as a manipulated variable by a mixture controller (30).