Hybrid Gear-Shift Control for Regenerative Braking Oversteer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hybrid vehicles face challenges in maintaining fuel efficiency while preventing oversteering in rear wheel-drive vehicles during regeneration operations, as reducing regeneration amount to address oversteering negatively impacts fuel efficiency and stability.
Innovation Solution
The controller adjusts the regeneration torque and interrupts motive power transmission between the input and output shafts of the automatic transmission to maintain regeneration while stabilizing the vehicle, ensuring the regeneration operation continues without causing oversteering and maintaining fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the motor performs a regeneration operation during deceleration in a rear wheel-drive vehicle, then fuel efficiency is improved, but the lateral force of the rear wheels decreases causing the vehicle to enter an oversteered state
Solution Approach 1:
The control device changes the gear ratio parameter of the automatic transmission during regeneration operation. By selecting an appropriate gear ratio that provides sufficient driving force to the rear wheels, the system maintains lateral force while enabling regeneration, thus resolving the contradiction between fuel efficiency and vehicle stability
Solution Approach 2:
The system dynamically adjusts the transmission gear ratio based on real-time vehicle conditions during deceleration. The control device selects gear ratios that balance regenerative braking needs with maintaining adequate rear wheel lateral force, preventing oversteer while maximizing energy recovery
2Stability of the object's composition
If the regeneration operation is stopped to resolve the oversteered state, then vehicle stability is improved, but fuel efficiency performance drops
Solution Approach 1:
The control device performs preliminary gear ratio selection before regeneration operation begins. By pre-selecting a gear ratio that ensures sufficient lateral force during the anticipated regeneration period, the system prevents oversteer from occurring in the first place, allowing continuous regeneration without stability issues
Solution Approach 2:
The system continuously monitors vehicle behavior and adjusts gear ratio selection based on feedback about lateral force and oversteer conditions. This real-time feedback mechanism allows the control device to maintain optimal gear ratios that prevent oversteer while maximizing regeneration effectiveness
3Productivity
If the automatic transmission performs a shift-down when the input shaft rotation speed reaches a gear-shifting point, then the transmission operates efficiently, but the torque of the rear wheels fluctuates due to inertia torque causing unstable vehicle behavior
Solution Approach 1:
The control device applies preliminary counter-measures by selecting gear ratios that anticipate and prevent torque fluctuations during shift-down operations. By choosing gear ratios that minimize inertia torque effects, the system prevents rear wheel torque fluctuations before they occur, maintaining stable vehicle behavior while preserving transmission efficiency
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively stabilizes the vehicle's behavior by reducing regeneration torque and preventing oversteering, while maintaining regeneration efficiency and preventing engine stall, thus enhancing fuel efficiency and stability.
Implementation Method 1
a motor 5 that generates a travel drive force of the automobile 1 and that supplies a high-voltage battery 9 with regenerative energy during deceleration of the automobile 1
Implementation Method 2
an automatic transmission 8 of which an input shaft 8a is connected to the engine 4 and the motor 5 and an output shaft 8b is connected to rear wheels 2R and which subjects an input rotation to gear-shifting at a transmission gear ratio corresponding to a selected shift stage and outputs the gear-shifted input rotation
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A vehicle gear-shifting control apparatus is equipped with an engine, a motor, an automatic transmission, a friction brake system, and a controller which executes, during deceleration of the vehicle during which the friction brake system is distributing a braking force to the front wheels and the rear wheels, regeneration control of imparting a regenerative braking torque to the rear wheels by causing the motor to perform a regeneration operation and gear-shifting control of changing a shift stage of the automatic transmission in accordance with the rotation speed of an input shaft. In an oversteered state of the vehicle during the regeneration control, the controller increases an input torque of the input shaft of the automatic transmission so that the regenerative braking torque decreases while maintaining a regeneration operation of the motor and interrupts motive power transmission between the input shaft and an output shaft of the automatic transmission.