BEV Accelerator Pedal Control for Intent-Based Deceleration Limits
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Solution Overview
Problem
Battery electric vehicles (BEVs) face challenges in simulating engine braking deceleration without engine friction, leading to unpredictable and unpleasant disturbances due to noise susceptibility in accelerator pedal position rate changes, which affects driver experience.
Innovation Solution
A control system and method for an electrified powertrain that continuously learns and updates maximum and minimum driver pedal position values based on driver intent, allowing for smooth transitions between normal and aggressive deceleration rates, and avoiding dead accelerator pedal scenarios by adjusting torque output accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If negative torque is commanded at the electrified powertrain to simulate engine braking deceleration, then energy recovery is achieved, but noise susceptibility in accelerator pedal position rate changes causes unpredictable disturbances
Solution Approach 1:
The system dynamically adjusts the deceleration rate based on driver intent detection. When the driver releases the accelerator pedal, the system transitions from a normal deceleration rate to an aggressive deceleration rate to maximize energy recovery. This dynamic adjustment resolves the contradiction by enabling high energy recovery only when driver intent indicates deceleration is desired, thereby maintaining control stability while maximizing energy capture.
Solution Approach 2:
The system continuously monitors accelerator pedal position rate of change and uses this feedback to detect driver intent. By establishing thresholds for pedal position changes, the system can distinguish between intentional driver actions and noise, enabling reliable detection of when the driver wants to decelerate. This feedback mechanism resolves the contradiction by ensuring energy recovery is activated only when driver intent is clearly indicated, preventing unpredictable disturbances.
2Loss of energy
If aggressive deceleration rate is used to maximize energy recovery, then energy capture is improved, but driver experience deteriorates due to unexpected disturbances
Solution Approach 1:
The system applies preliminary anti-action by detecting driver intent before activating aggressive deceleration. When the system detects that the driver has released the accelerator pedal (indicating intent to decelerate), it prepares to switch to aggressive deceleration mode. This preliminary detection prevents unexpected disturbances by ensuring the driver's intent is known before the aggressive deceleration is applied, thereby maintaining driver experience while maximizing energy recovery.
Solution Approach 2:
The system changes the deceleration rate parameter based on detected driver intent. When driver intent indicates deceleration is desired, the system transitions from a normal deceleration rate to an aggressive deceleration rate. This parameter change resolves the contradiction by enabling high energy recovery only when appropriate, preventing unexpected disturbances that would degrade driver experience.
3Ease of operation
If accelerator pedal position rate of change is monitored for controlling electrified powertrain, then deceleration control is achieved, but noise susceptibility causes unpredictable disturbances
Solution Approach 1:
The system performs preliminary action by establishing thresholds for accelerator pedal position changes before monitoring begins. These thresholds define what constitutes a significant driver action versus noise. By having these thresholds pre-established, the system can reliably distinguish between intentional driver actions and noise, resolving the contradiction between achieving deceleration control and maintaining control stability.
Solution Approach 2:
The system continuously monitors accelerator pedal position rate of change and uses feedback against established thresholds to detect driver intent. This feedback mechanism enables reliable distinction between intentional driver actions and noise, resolving the contradiction by ensuring control actions are taken only when driver intent is clearly indicated, thereby maintaining both deceleration control and control stability.
Data Source
AI summary
A control system for an electrified powertrain of a battery electric vehicle (BEV) includes an accelerator pedal and a controller configured to determine maximum and minimum values for driver pedal position based on a first position of the accelerator pedal indicative of a first driver pedal position, determine whether the accelerator pedal position remains constant relative to the first position, when the accelerator pedal position does not remain constant and moves to a second position indicative of a second driver pedal position, detect that driver pedal position is increasing when the second driver pedal position is greater than the first minimum value and setting the first maximum value to the second driver pedal position and detect decreasing driver pedal position when the second driver pedal position is less than the first maximum value and setting the minimum value to the second driver pedal position.