Internal Combustion Engine Mixture Control for Methane Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for operating internal combustion engines with natural gas fail to achieve optimal methane conversion in the catalyst due to insufficient rich mixture shift, resulting in suboptimal emissions control.
Innovation Solution
A method that varies the mixture control factor after detecting a lean/rich jump to cause a defined shift in the lambda air ratio towards a rich mixture, including increased control factor and holding times, ensuring effective methane conversion in the catalyst.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a lengthy holding time duration is used after rich detection to ensure stable mixture control, then mixture stability is improved, but methane conversion in the catalyst becomes insufficient
Solution Approach 1:
The control method applies a tendential rich shift before the holding time duration expires, preparing the mixture composition in advance to ensure sufficient methane conversion. This preliminary action compensates for the delayed response caused by the lengthy holding time, allowing the catalyst to receive adequately rich mixture conditions.
Solution Approach 2:
The control factor is dynamically adjusted during the holding time duration by applying a tendential rich shift when lean mixture is detected. This dynamic adjustment allows the system to adapt to changing mixture conditions while maintaining overall stability, ensuring methane conversion requirements are met despite the fixed holding time structure.
2Stability of the object's composition
If a tendential rich shift is applied during holding time, then mixture stability is maintained, but the mean mixture achieves only minimal rich shift insufficient for optimum methane conversion
Solution Approach 1:
The control method changes the mixture composition parameter by applying a tendential rich shift during the holding time duration. This parameter change increases the mean rich shift of the mixture, transforming it from a minimal shift to a sufficient shift that enables optimum methane conversion in the catalyst while maintaining stability.
3Reliability
If the control factor is increased further during holding time when lean mixture is detected, then methane conversion is improved, but control complexity increases
Solution Approach 1:
The control method uses feedback from the lambda probe to detect lean mixture conditions during the holding time duration. Based on this feedback, the control factor is increased further to apply an additional rich shift. This feedback mechanism improves methane conversion by responding to actual mixture conditions while keeping control complexity manageable through rule-based decision logic.
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 significantly improves methane conversion in the catalyst, leading to enhanced emissions control and reduced pollutant emissions.
Implementation Method 1
a lambda value of an air/fuel mixture being regulated by means of lambda control as a function of a signal from a lambda probe
Implementation Method 2
For a conversion of methane in the catalyst, a slightly rich mixture in the catalyst is required
Implementation Method 3
The injection valves are in this case supplied with natural gas via a low-pressure common rail and inject the natural gas into the suction pipe intermittently
Data Source
AI summary
A method for operating an internal combustion engine (100), particularly of a motor vehicle, operated with a gas as fuel, a lambda value of an air/fuel mixture being regulated by means of lambda control as a function of a signal from a lambda probe (130), and, when a lean/rich jump is detected by the lambda probe (130), a mixture control factor (GRF) which controls the mixture composition being varied at least for a predeterminable time such that a shift of the lambda air ratio toward rich is caused, is characterized in that the mixture control factor (GRF) is varied in such a way that an additional defined shift of the lambda air ratio toward rich is caused.