Drive Device Lambda Sensor Control for Fuel Efficiency
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Solution Overview
Problem
Existing methods for operating drive devices, such as internal combustion engines, fail to precisely set the combustion air ratio, leading to inefficient fuel consumption and unstable operation of vehicle catalytic converters.
Innovation Solution
A method that uses two lambda sensors to measure oxygen content upstream and downstream of a catalytic converter, adjusting the combustion air ratio periodically with a variable mean value and determined amplitude and frequency during a calibration mode to ascertain a threshold value, which is then used to set the target combustion air ratio during normal operation, ensuring efficient and stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the combustion air ratio is set based on conventional methods using single lambda sensor feedback, then the control system is simple, but the fuel consumption is high and the catalytic converter operation is unstable
Solution Approach 1:
The patent implements dual feedback loops: an outer feedback loop uses the second lambda sensor downstream of the catalytic converter to detect oxygen content and adjust the combustion air ratio, while an inner feedback loop uses the first lambda sensor upstream to provide rapid response. This nested feedback structure enables precise fuel consumption optimization without requiring overly complex control architecture
Solution Approach 2:
The control system is segmented into two functional parts: a first control unit that processes signals from the upstream lambda sensor for rapid combustion adjustment, and a second control unit that processes signals from the downstream lambda sensor for catalytic converter optimization. This segmentation allows each control unit to specialize in specific control tasks, improving overall efficiency without creating a monolithic complex system
2Productivity
If the combustion air ratio is adjusted frequently to optimize performance, then the fuel consumption decreases, but the catalytic converter conversion capacity becomes unstable
Solution Approach 1:
The patent implements periodic calibration cycles where the combustion air ratio is deliberately modulated at determined amplitude and frequency during calibration operating mode. This periodic action allows the system to learn and adapt to the specific catalytic converter characteristics, establishing stable operating parameters that maintain both fuel efficiency and converter stability during normal operation
Solution Approach 2:
The system performs preliminary calibration by periodically adjusting the combustion air ratio before normal operation to determine optimal threshold values. This preliminary action establishes the foundation for stable catalytic converter operation, ensuring that subsequent fuel efficiency optimizations do not compromise converter stability
3Adaptability or versatility
If a fixed threshold value is used for the second measured value, then the control logic is simple, but the system cannot adapt to varying operating conditions and catalytic converter aging
Solution Approach 1:
The patent transitions from a fixed threshold value to a dynamic threshold determination process. During calibration operating mode, the system periodically varies the combustion air ratio and identifies the threshold value where the second lambda sensor signal variation falls below a determined threshold. This dynamic approach allows the threshold to adapt to catalytic converter aging and varying operating conditions while maintaining manageable control logic through structured calibration procedures
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 precise adjustment of the combustion air ratio, reducing fuel consumption and enhancing the conversion performance of the catalytic converter, resulting in stable and efficient operation of the drive device.
Implementation Method 1
a first measured value describing a residual oxygen content in the exhaust gas is measured by means of a first lambda sensor arranged upstream of the exhaust gas posttreatment device
Implementation Method 2
a second measured value describing the residual oxygen content in the exhaust gas is measured by means of a second lambda sensor arranged downstream of the exhaust gas posttreatment device
Implementation Method 3
an exhaust gas posttreatment device designed as a vehicle catalytic converter for posttreatment of the exhaust gas
Data Source
AI summary
A method for operating a drive device having a drive unit producing exhaust gas and an exhaust gas posttreatment device designed as a vehicle catalytic converter for posttreatment of the exhaust gas. A first measured value describing the residual oxygen content in the exhaust gas is measured by a first lambda sensor arranged upstream of the exhaust gas posttreatment device and a second measured value describing the residual oxygen content in the exhaust gas is measured by a second lambda sensor arranged downstream of the exhaust gas posttreatment device. The combustion air ratio of a fuel-air mixture used to operate the drive unit is set during an at least temporarily performed normal operating mode on the basis of the first measured value, the second measured value, and a threshold value for the second measured value.