Vehicle Driving Force Control System for Re-Acceleration
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Solution Overview
Problem
Existing driving force control systems for vehicles with automatic transmissions fail to accurately set the gear position during deceleration, leading to insufficient driving force during re-acceleration, causing discomfort and poor acceleration performance due to estimation errors in driver intention and driving tendency.
Innovation Solution
A driving force control system that uses a controller to set an appropriate speed ratio for re-acceleration by storing and analyzing acceleration characteristics and traveling data, including vehicle speed, acceleration, and engine speed, to determine the desired re-acceleration-time acceleration and adjust the transmission gear position accordingly before re-acceleration begins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gear position is uniformly set during deceleration based on estimated driving tendency, then the acceleration performance can be improved when the vehicle is re-accelerated, but the gear position may not be adequate due to estimation errors, causing further downshift and insufficient driving force
Solution Approach 1:
The controller monitors the actual accelerator operation amount during deceleration and compares it with the estimated sporty driving tendency threshold. When the actual accelerator operation exceeds the threshold, the controller determines the driver has sporty driving tendency and adjusts the gear position accordingly. This feedback mechanism resolves the contradiction by using real operational data to validate and correct the estimation, ensuring accurate gear positioning for optimal acceleration performance.
2Productivity
If downshift is performed during deceleration to prepare for re-acceleration, then the acceleration performance is improved, but if the downshift is not sufficient, further downshift may be performed during re-acceleration causing driver discomfort and poor acceleration feeling
Solution Approach 1:
The controller performs preliminary gear position setting during deceleration by determining the appropriate gear position in advance based on the driver's sporty driving tendency and current vehicle state. This preliminary action ensures the transmission is already in the optimal gear position when re-acceleration begins, preventing the need for further downshifts during acceleration and providing smooth, comfortable acceleration performance.
3Productivity
If the automatic transmission is shifted down to a lower gear position during deceleration for sporty driving tendency, then the acceleration performance is improved, but the gear position established after downshift may not be adequate due to individual differences in driving tendency
Solution Approach 1:
The system dynamically adjusts the gear position based on real-time monitoring of accelerator operation amount and comparison with adaptively determined thresholds. The controller continuously evaluates whether the driver exhibits sporty driving tendency by comparing actual accelerator operation with threshold values, and adjusts the gear position dynamically accordingly. This dynamic adaptation resolves the contradiction by making the system responsive to individual driver behavior patterns rather than using fixed, pre-defined gear positioning.
Data Source
AI summary
A driving force control system of a vehicle installed with an automatic transmission that transmits torque generated by an engine to drive wheels while changing the speed is provided for controlling driving force based on the vehicle speed and the accelerator operation amount. In the driving force control, an acceleration characteristic that defines the relationship between re-acceleration-time acceleration as a control index used when the vehicle travels while being re-accelerated after deceleration traveling, and the vehicle speed, is stored, and the re-acceleration-time acceleration corresponding to the current vehicle speed is obtained, based on traveling data of the vehicle obtained before the deceleration traveling, and the acceleration characteristic. Then, the speed ratio of the automatic transmission which can realize the obtained re-acceleration-time acceleration is set, before the re-acceleration traveling is started.