Fuel Tank Ventilation Valve Dynamics for Carbon Filter Regeneration
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Solution Overview
Problem
In vehicles with hybrid, plug-in, or automatic start-stop engines, the activated carbon filter in fuel tank ventilation systems is not adequately regenerated due to infrequent load conditions, leading to potential hydrocarbon leaks into the atmosphere.
Innovation Solution
The control unit adjusts the operation of valves in the fuel tank ventilation system based on the load factor and operating cycle duration of the engine to manage the flow of fuel vapors and air, preventing filter overload and minimizing hydrocarbon release, by altering the opening pressure, cross-section, and duration of tank shut-off, ventilation, and regeneration valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the activated carbon filter is dimensioned greater to prevent hydrocarbon leaks during extended periods without regeneration, then hydrocarbon release is reduced, but installation space and costs increase
Solution Approach 1:
The patent applies dynamics by making the valve opening cross-section variable rather than fixed. The control unit adjusts the opening cross-section of the tank shut-off valve dynamically based on the loading condition of the activated carbon filter. When the filter is highly loaded and regeneration is delayed, the valve opening is reduced to limit vapor flow and prevent filter saturation. This dynamic adjustment allows a smaller filter to effectively manage hydrocarbon emissions under varying operating conditions without requiring a permanently larger filter capacity.
Solution Approach 2:
The patent changes the parameter of valve opening cross-section based on filter loading conditions. The control unit monitors the loading condition of the activated carbon filter and adjusts the valve opening parameter accordingly. This parameter change enables the system to optimize vapor flow management in real-time, preventing hydrocarbon leaks during extended periods without regeneration while maintaining a compact filter size.
2Reliability
If the tank shut-off valve opening cross-section is reduced to prevent filter overload during extended periods without regeneration, then filter capacity is preserved, but vapor venting capability is limited
Solution Approach 1:
The patent applies dynamics by making the valve opening cross-section variable rather than fixed. The control unit adjusts the opening cross-section of the tank shut-off valve dynamically based on the loading condition of the activated carbon filter. When the filter is highly loaded and regeneration is delayed, the valve opening is reduced to limit vapor flow and prevent filter saturation. This dynamic adjustment allows a smaller filter to effectively manage hydrocarbon emissions under varying operating conditions without requiring a permanently larger filter capacity.
Solution Approach 2:
The patent changes the parameter of valve opening cross-section based on filter loading conditions. The control unit monitors the loading condition of the activated carbon filter and adjusts the valve opening parameter accordingly. This parameter change enables the system to optimize vapor flow management in real-time, preventing hydrocarbon leaks during extended periods without regeneration while maintaining a compact filter size.
3Object-generated harmful factors
If the valve opening duration is extended to improve filter regeneration, then hydrocarbon release is reduced, but energy consumption and potential leaks increase
Solution Approach 1:
The patent applies periodic action by implementing intermittent regeneration cycles rather than continuous operation. The control unit activates the regeneration process periodically based on the loading condition of the activated carbon filter. During regeneration, the tank shut-off valve is opened for specific durations to allow vapor flow that flushes the filter. This periodic activation enables the system to reduce hydrocarbon releases by maintaining filter effectiveness through scheduled regeneration events, while avoiding the energy consumption and potential leaks associated with continuous valve operation.
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 prevents hydrocarbon leaks without increasing the size of the activated carbon filter, ensuring efficient regeneration and maintaining system integrity by optimizing valve operations according to engine conditions and filter loading.
Implementation Method 1
an activated carbon filter which is usually connected to the fuel tank by a first gas line
Implementation Method 2
which automatically opens at a predetermined overpressure or negative pressure in the fuel tank
Data Source
AI summary
A device for ventilating a fuel tank of an internal combustion engine in particular of a fuel tank of an internal combustion engine of a motor vehicle includes an activated carbon filter and at least one valve which is controllable by a control unit. To prevent leakage of hydrocarbons into the environment without enlargement of the activated carbon filter the control unit controls the valve in dependence on a load factor of the activated carbon filter and/or in dependence on an operating cycle duration of the internal combustion engine.