Drive Force Distribution Control for Hybrid Four-Wheel Drive
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional drive force distribution control devices for hybrid four-wheel drive vehicles fail to achieve consistent four-wheel drive performance across electric motor operating and non-operating modes due to disparities in estimated torque precision, leading to perceived inferior performance in electric motor operating modes.
Innovation Solution
A drive force distribution control device that calculates a corrected drive force distribution command value for driven wheels, with a greater correction amount in electric motor operating modes than in non-operating modes, ensuring equivalent four-wheel drive performance under the same conditions by accounting for the precision differences in engine and electric motor torque estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the drive force distribution control device uses a fixed correction amount for all operating modes, then the device complexity is reduced, but the four-wheel drive performance consistency between electric motor operating mode and non-operating mode deteriorates
Solution Approach 1:
The correction amount is made dynamic rather than fixed, allowing it to change based on the operating mode. The control device determines whether the electric motor is operating and selects different correction amounts accordingly, enabling the system to adapt to different operating conditions and maintain consistent four-wheel drive performance across modes.
Solution Approach 2:
The correction amount parameter is changed based on the operating mode. When the electric motor is operating, a first correction amount is applied; when not operating, a second correction amount is applied. This parameter change ensures that the drive force distribution command value accurately reflects the actual drive force in each mode, maintaining performance consistency.
2Reliability
If the correction amount is increased in electric motor operating mode, then the four-wheel drive performance consistency is improved, but the device complexity increases due to mode determination requirements
Solution Approach 1:
The control device uses feedback from the operating mode determination to adjust the correction amount. By continuously monitoring whether the electric motor is operating and using this information to select the appropriate correction amount, the system maintains accurate drive force distribution and consistent four-wheel drive performance across different modes.
3Ease of manufacture
If the same estimated main drive wheel drive force value is used for both operating modes, then the calculation process is simplified, but the perceived four-wheel drive performance in electric motor operating mode becomes inferior
Solution Approach 1:
Different correction amounts are applied locally to different operating modes based on their specific characteristics. The control device adjusts the correction amount according to whether the electric motor is operating, ensuring that each mode receives the appropriate correction level. This local differentiation improves the perceived four-wheel drive performance in electric motor operating mode while maintaining calculation simplicity through mode-based categorization.
Data Source
AI summary
A device for controlling the distribution of drive force includes a driven wheel drive force distribution reference command value calculator configured to determine a driven-wheel-oriented drive force distribution reference command value from the estimated value of the drive force sent to the drive wheels and a drive force reference distribution ratio, and a driven wheel drive force distribution command value calculator configured to determine a driven-wheel-oriented drive force distribution command value by correcting the driven wheel drive force distribution reference command value by a correction amount that differs between the electric motor operating mode and the electric motor non-operating mode, and to make the correction amount for the electric motor operating mode greater than the correction amount for the electric motor non-operating mode.