Active Purge System Accuracy via Temperature and HC Weighting
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Solution Overview
Problem
The existing purge control methods for fuel evaporative gas in vehicles, particularly in hybrid electric vehicles, face inaccuracies in calculating the purge fuel amount due to reliance on external concentration sensors, leading to unstable air-fuel ratios and difficulties in limiting the purge flow rate, which can result in insufficient compliance with hydrocarbon emission regulations.
Innovation Solution
A method that corrects the purge fuel amount using a primary weighting factor based on ambient air temperature and hydrocarbon concentration, and a secondary weighting factor for the purge learning value, reflecting changes in air-fuel ratio control values to improve accuracy and stability, thereby enhancing the active purge system's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a gas concentration model based on external concentration sensor values is used for purge fuel amount calculation, then the system can implement purge control, but the model concentration value accuracy is lower than actual concentration results, leading to excessive purge learning value increases
Solution Approach 1:
The patent introduces a concentration correction value as an intermediary parameter that mediates between the external concentration sensor readings and the actual canister concentration. This correction value compensates for the accuracy discrepancy, allowing the system to use the simpler external sensor while achieving accurate purge fuel amount calculation through the corrective intermediary layer.
Solution Approach 2:
The patent transforms the concentration parameter by introducing a correction factor that adjusts the model concentration value based on the difference between external sensor readings and actual canister concentration. This parameter transformation maintains the simplicity of using external sensors while improving measurement accuracy through mathematical correction of the concentration parameter.
2Reliability
If purge learning value is excessively increased to compensate for inaccurate model concentration, then purge control can be adjusted, but it becomes difficult to limit the purge flow rate
Solution Approach 1:
The patent applies preliminary anti-action by pre-calculating and applying a concentration correction value before determining the purge fuel amount. This preventive correction prevents the purge learning value from becoming excessively large in the first place, thereby maintaining both reliable purge control adjustment and effective purge flow rate limiting without needing to compensate through excessive learning values.
3Device complexity
If air-fuel ratio variation conditions and external conditions are not excluded from purge fuel amount calculation, then the calculation can be simplified, but it becomes difficult to solve unstable air-fuel ratio behavior and purge rate limiting
Solution Approach 1:
The patent applies local quality by selectively excluding specific conditions (air-fuel ratio variation conditions and external conditions) from the purge fuel amount calculation only when they would adversely affect stability. Rather than uniformly excluding or including all conditions, the system applies conditional exclusion based on local quality assessment of each operating condition, maintaining calculation simplicity while ensuring air-fuel ratio stability.
4Adaptability or versatility
If existing purge control methods are used, then the system can operate with current components, but there is a very high probability of control error and insufficient response to HC emission regulations
Solution Approach 1:
The patent implements feedback by continuously monitoring the difference between external concentration sensor readings and actual canister concentration, then using this feedback to adjust the concentration correction value. This feedback mechanism ensures high reliability and emission regulation compliance while maintaining adaptability to current system components, as the feedback loop continuously optimizes the correction based on actual performance.
Data Source
AI summary
An embodiment is a method including controlling a purge fuel amount of an active purge system (APS), the controlling including correcting the purge fuel amount using a primary weighting factor obtained using an ambient air temperature and a hydrocarbon (HC) concentration in purge gas fuel as input values, and correcting the corrected purge fuel amount using a secondary weighting factor due to a purge learning value. Some embodiments further include controlling of the purge fuel amount applies a purge execution condition, and the purge execution condition on the basis of a negative pressure of an intake manifold and a vehicle speed of the vehicle in which a purge flow rate exhibits as being greater than or equal to a predetermined value.