Electronic Throttle Airflow Compensation via Learned Correction Maps
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Solution Overview
Problem
Electronic throttle control systems face challenges in adapting to airflow variations caused by throttle body deposits, leading to drivability issues such as idle roll and stalls, and these adaptations are lost when the controller is reflashed or swapped, affecting driving performance and stable idle speed.
Innovation Solution
A correction system and method that generates a learned-correction value for throttle position using a generator module, writes it to a throttle position correction array when stability conditions are met, and updates non-volatile and volatile histograms to maintain and initialize airflow compensation values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ETC system slowly adapts or learns to compensate for airflow variations, then drivability issues such as idle roll and stalls are prevented, but the speed of learning compensating values becomes an impediment to improving driving performance and stable idle speed
Solution Approach 1:
The system dynamically adjusts the learning speed based on operating conditions. During certain engine operations, the controller accelerates the rate at which it learns compensating values for throttle body deposits, while during other operations it maintains slower learning to ensure stability. This dynamic adjustment resolves the contradiction between fast learning (productivity) and stable adaptation (reliability).
Solution Approach 2:
The controller changes the learning parameters (such as the rate of correction application) based on engine operating conditions. By modifying these parameters dynamically, the system can speed up learning when conditions permit and slow down when stability is prioritized, thus resolving the trade-off between learning speed and drivability stability.
2Adaptability or versatility
If the controller is reflashed or swapped, then new controllers can be installed, but the learned values of airflow correction compensating for coking are lost and drivability issues result
Solution Approach 1:
The system creates and stores a map or array of learned correction values that can be transferred between controllers. When a controller is replaced, the learned values can be copied from the old controller to the new one, preserving the compensating information for throttle body deposits and preventing loss of learned corrections.
Solution Approach 2:
The system performs preliminary learning and storage of correction values before controller replacement occurs. By maintaining these learned values in a transferable format and preparing them for transfer in advance, the system ensures that when a new controller is installed, the learned corrections are already available and can be immediately applied, preventing drivability issues.
3Reliability
If the throttle position is adjusted to allow for an increase in airflow that compensates for less flow due to coking, then drivability issues are prevented, but the relationship between throttle position and airflow is altered by statistical build variations in ETC system components
Solution Approach 1:
Instead of applying a single global correction to the throttle position, the system implements local corrections through a map or array of correction values specific to different throttle positions and operating conditions. This allows precise, localized compensation for throttle body deposits while accounting for component variations, maintaining the accurate relationship between throttle position and airflow at each specific operating point.
Solution Approach 2:
The system continuously monitors actual airflow and throttle position, using this feedback to refine and update the correction values in the map. This closed-loop feedback mechanism compensates for manufacturing variations and ensures that the throttle position adjustments accurately achieve the desired airflow compensation for throttle body deposits.
Data Source
AI summary
A correction system and method for an electronic throttle control includes a generator module that generates a learned-correction value corresponding to a first air-learn index. The learned-correction value is used to compensate a throttle position. A correction module writes to a throttle position correction array with the learned-correction value when an air-learn value equals a predetermined stability threshold.