Active Carbon Filter Regeneration Control for Motor Vehicles
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Solution Overview
Problem
Existing control methods for active carbon filters in motor vehicle tank ventilation devices lack precision in determining the loading status and offer limited options for regeneration, particularly during engine overrun or start-stop conditions.
Innovation Solution
A control method that determines the hydrocarbon content in the tank ventilation device upstream of the engine and adjusts the opening time of the tank ventilation valve based on this content, temperature of the exhaust treatment system, and engine operational parameters to precisely assess and regenerate the active carbon filter during overrun or standstill modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the loading status of the active carbon filter is determined using measured values from a lambda probe downstream of the engine, then the determination can be made using existing exhaust gas measurement systems, but the precision and accuracy of the loading determination is insufficient
Solution Approach 1:
An HC sensor is introduced as an intermediary measurement device between the fuel tank ventilation device and the exhaust system. This sensor directly measures the hydrocarbon content in the tank gas mixture before it enters the active carbon filter, providing accurate upstream concentration data that enables precise loading status determination without relying on downstream exhaust gas measurements.
2Adaptability or versatility
If the tank ventilation valve is opened for regeneration during engine overrun mode, then the active carbon filter can be regenerated using the existing exhaust gas flow, but the regeneration option is limited and cannot be used during standstill conditions
Solution Approach 1:
The control system dynamically adjusts the tank ventilation valve opening based on real-time detection of engine operational modes (overrun or standstill). During overrun mode, the valve opens to allow exhaust gas flow through the active carbon filter for regeneration. During standstill conditions, the system alternatively uses a tank gas pump to actively transport tank gas through the filter, enabling regeneration capability across multiple operational scenarios.
Solution Approach 2:
The system utilizes the engine's own operational characteristics (overrun mode creating negative pressure, standstill conditions) to enable regeneration without requiring external intervention. During overrun, the engine's own exhaust flow provides the regenerating gas stream. During standstill, the tank gas pump leverages the existing tank gas pressure to drive regeneration, making the system self-sufficient across different operating conditions.
3Reliability
If hydrocarbons are introduced into the exhaust system for regeneration, then the active carbon filter can be cleaned, but excessive hydrocarbon introduction may cause temperature increases that affect catalyst performance
Solution Approach 1:
The control system continuously monitors the temperature of the exhaust treatment system and uses this feedback to regulate the regeneration process. When the temperature approaches thresholds that could affect catalyst performance, the system adjusts the tank ventilation valve opening duration or intensity, and coordinates with the tank gas pump to control the rate of hydrocarbon introduction, ensuring regeneration effectiveness while maintaining safe operational temperatures.
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 method allows for more accurate determination of active carbon filter loading and enables regeneration during engine standstill, preventing excessive hydrocarbon introduction into the exhaust system, thus maintaining optimal operational temperatures and extending filter lifespan.
Implementation Method 1
a gas mixture which has passed through an active carbon filter (52)
Implementation Method 2
the supply to the catalytic converter (38) of hydrocarbons that have not been combusted (or only some of which have been combusted) in the internal combustion engine (10) in overrun mode leads to a subsequent reduction thereof in the exhaust gas flow due to oxidation or reduction
Implementation Method 3
The hydrocarbon content in the tank ventilation device (12) is determined by use of an HC sensor attached in the area of the tank ventilation device (12)
Data Source
AI summary
A control method for adjusting the hydrocarbon concentration in an active carbon filter of a tank ventilation device of a motor vehicle, includes the acts of: detecting an operational parameter of the internal combustion engine of the vehicle; determining the hydrocarbon content of a fuel tank gas mixture in the fuel tank ventilation device; and opening the tank ventilation valve of the tank ventilation device for a defined length of time in accordance with the determined hydrocarbon content when the operational parameter of the internal combustion engine displays an overrun mode or a standstill mode of the internal combustion engine generated by a start-stop system.