Gas Engine Exhaust Control Switching Modes for NOx and Fuel
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Solution Overview
Problem
Existing exhaust-gas purification devices for gas engines do not effectively address NOx emission restrictions based on environmental conditions, leading to increased fuel consumption and installation costs, especially in high-temperature and low-humidity environments.
Innovation Solution
An exhaust-gas control device that switches to a low NOx operation mode when high-temperature and low-humidity conditions are detected, adjusting the air-fuel ratio and ignition timing to reduce NOx emissions temporarily, while maintaining stable fuel consumption and power generation output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If NOx restriction operation is performed constantly by increasing target air-fuel rate and retarding ignition timing, then NOx emissions are reduced, but fuel consumption deteriorates
Solution Approach 1:
The patent implements dynamic switching between two operation modes (first operation mode for stable fuel consumption and second operation mode for NOx reduction) based on environmental conditions. The control system continuously monitors ambient temperature and humidity, and automatically transitions between modes to optimize both fuel consumption and NOx emissions control, rather than maintaining a fixed operation mode constantly
Solution Approach 2:
The patent changes operational parameters (target air-fuel rate and target ignition timing) based on environmental conditions. In the second operation mode activated under high temperature and low humidity conditions, the target air-fuel rate is increased and target ignition timing is retarded compared to the first operation mode, thereby reducing NOx emissions when environmental conditions require it
2Object-generated harmful factors
If expensive denitration facilities and output restriction are implemented for NOx control, then NOx emissions are reduced, but power generation output and fuel consumption deteriorate
Solution Approach 1:
The patent replaces expensive permanent denitration facilities with a cost-effective control strategy that uses existing engine control capabilities (air-fuel ratio and ignition timing control) to achieve temporary NOx reduction when needed, avoiding large capital investment in permanent emission control equipment
Solution Approach 2:
The system dynamically adjusts operation mode based on environmental conditions rather than maintaining constant output restriction. This allows the gas engine to operate at full power during normal conditions and only applies NOx reduction measures when high temperature and low humidity conditions are detected, thereby maintaining productivity while controlling emissions when necessary
3Object-generated harmful factors
If NOx restriction operation is performed temporarily under high temperature and low humidity conditions, then NOx emissions are reduced without continuous fuel consumption deterioration, but requires environmental monitoring and mode switching control
Solution Approach 1:
The patent applies NOx reduction control measures specifically under local environmental conditions (high temperature and low humidity) rather than universally. The control system monitors ambient temperature and humidity sensors to determine when to activate the second operation mode, applying NOx restriction only where and when environmental conditions require it
Solution Approach 2:
The control system continuously monitors environmental parameters (ambient temperature and humidity) and provides feedback to the operation mode switching logic. Based on this feedback, the system automatically transitions between first and second operation modes, ensuring NOx reduction is applied only when environmental conditions warrant it while maintaining simple and intuitive control
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 solution allows for efficient NOx reduction and improved fuel consumption by switching between NOx restriction and stable operation modes based on environmental conditions, reducing the need for continuous NOx reduction measures and minimizing fuel consumption and installation costs.
Implementation Method 1
control the ignition timing and the air-fuel ratio... restricting production of NOx... increases the combustion temperature
Data Source
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AI summary
An object is to provide an exhaust-gas control device for a gas engine whereby NOx is reduced and fuel consumption is improved by performing NOx restriction operation when an environmental or geographical condition in which the amount of NOx emission needs to be temporarily restricted is satisfied, and otherwise performing stable operation focusing on the fuel consumption. The exhaust-gas control device for a gas engine includes: a basic operation mode unit (80) using the first target ignition timing and the first target air-fuel rate at which the fuel consumption rate is the optimum; a low-NOx operation mode unit (82) using the second target ignition timing retarded from the first target ignition timing and the second target air-fuel rate increased from the first target air-fuel rate; a NOx reduction demand determination unit (86) for determining whether to restrict the amount of NOx emission temporarily, and an switching unit to operation mode (84) for switching the operation mode to the low NOx operation mode while the reduction demand condition is satisfied by the NOx reduction demand determination unit.