Dynamic Pedal Mapping for Hybrid Vehicle Engine Activation
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Solution Overview
Problem
Existing hybrid electric vehicles face challenges in controlling the transition from electric-only mode to gas engine mode due to static accelerator pedal mappings, which result in premature engine activation and reduced fuel efficiency, as they fail to accommodate dynamic changes in vehicle conditions such as battery state of charge.
Innovation Solution
A control system that dynamically adjusts the pedal position mapping by modifying the wheel output demand based on a variable pull-up threshold, which changes according to conditions like battery state of charge, reducing pedal position sensitivity near the threshold to delay engine activation and maximize electric mode usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a static accelerator pedal mapping is used, then the system is simple to implement, but the engine activates prematurely reducing fuel efficiency
Solution Approach 1:
The patent applies dynamics by transitioning from a static accelerator pedal mapping to a dynamic mapping that adjusts in real-time based on vehicle conditions. The controller modifies the relationship between pedal position and wheel output demand based on factors like battery state of charge, causing the mapping to change continuously rather than remain fixed. This resolves the contradiction by enabling fuel efficiency improvements through adaptive control while managing complexity through algorithmic adjustments rather than hardware changes.
Solution Approach 2:
The patent implements parameter changes by modifying the accelerator pedal mapping parameters dynamically. Specifically, it adjusts the wheel output demand corresponding to each pedal position based on varying vehicle conditions such as battery state of charge. This allows the system to optimize fuel efficiency by changing operational parameters (the mapping relationship) without altering the physical structure, thereby improving energy efficiency while maintaining acceptable system complexity.
2Speed
If the pedal position sensitivity is high, then the vehicle responsiveness is improved, but the engine starts more frequently near the pull-up threshold
Solution Approach 1:
The patent applies dynamics by making the accelerator pedal mapping adaptive rather than static. The controller dynamically adjusts the mapping based on how close the demanded wheel output is to the engine pull-up threshold and other vehicle conditions. When near the threshold, the mapping is modified to reduce sensitivity, preventing premature engine activation. This resolves the contradiction by enabling the system to maintain high responsiveness when appropriate while reducing engine starts when near threshold conditions, thereby extending electric mode duration.
Solution Approach 2:
The patent implements parameter changes by modifying the pedal position to wheel output demand mapping parameters based on real-time vehicle conditions. When the vehicle operates near the engine pull-up threshold, the controller adjusts the mapping parameters to reduce sensitivity, requiring a larger pedal position change to trigger engine activation. This allows the system to maintain responsiveness during normal operation while reducing unnecessary engine starts, thus extending productive electric mode duration.
3Adaptability or versatility
If a fixed pull-up threshold is used, then the control logic is simple, but the system cannot adapt to varying battery state of charge conditions
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed pull-up threshold to a dynamic threshold that varies with battery state of charge and other vehicle conditions. The controller continuously adjusts the effective threshold based on real-time measurements, enabling the system to adapt to changing battery conditions. This resolves the contradiction by providing adaptability to varying battery states while managing complexity through software-based threshold adjustment rather than multiple hardware thresholds.
Solution Approach 2:
The patent implements parameter changes by making the pull-up threshold a variable parameter rather than a fixed value. The controller modifies the threshold parameter based on battery state of charge, temperature, and other vehicle conditions. This allows the system to adapt to varying battery conditions optimally while maintaining relatively simple control logic through a single adaptive threshold mechanism rather than multiple fixed thresholds or complex decision trees.
Data Source
AI summary
A hybrid vehicle operates in an electric-drive-only mode and one or more modes using an internal combustion engine. A control pedal is movable to respective positions by a driver for indicating a desired vehicle motion. A controller selectably activates the engine according to instantaneous values of a variable wheel output demand and a variable pull-up threshold. The pedal position is converted to a respective instantaneous wheel output demand in response to an initial value from a mapping relationship that is modified in response to a difference between the initial value and the variable pull-up threshold. The pull-up threshold may preferably be dynamically determined according to a state of charge of a battery for powering the electric drive. The modification to the wheel output demand preferably reduces the slope of the mapping relationship near the pull-up threshold to reduce pedal position sensitivity in a region near the dynamically varying pull-up threshold.


