Torque Converter Bypass Clutch Control for Regenerative Braking
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Solution Overview
Problem
Existing regenerative braking systems in hybrid and electric vehicles fail to optimize energy recapture during braking events, leading to inefficiencies and potential energy waste due to inadequate coordination between powertrain and braking systems, resulting in torque holes and unnecessary stress on the torque converter.
Innovation Solution
A vehicle system with a controller that adjusts the closed-state torque capacity of the torque converter bypass clutch in proportion to negative drive wheel torque commands during regenerative braking events, ensuring efficient energy recapture and preventing unnecessary stress on the torque converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking is implemented without coordinating the torque converter bypass clutch, then kinetic energy can be recaptured to charge the battery, but torque holes occur and unnecessary stress is applied to the torque converter
Solution Approach 1:
The clutch torque capacity is dynamically adjusted during regenerative braking events based on the magnitude of negative wheel torque commands. The controller continuously modulates the clutch torque capacity to match the instantaneous regenerative braking torque, preventing torque holes and excessive stress on the torque converter while maximizing energy recapture.
Solution Approach 2:
The system changes the torque capacity parameter of the bypass clutch in proportion to negative wheel torque commands during regenerative braking. By adjusting this parameter dynamically rather than maintaining a fixed capacity, the system optimizes both energy recapture efficiency and protects against torque converter stress.
2Reliability
If the bypass clutch torque capacity is maintained at high levels during regenerative braking, then torque holes are prevented, but energy recapture efficiency decreases due to unnecessary stress on the torque converter
Solution Approach 1:
The clutch torque capacity transitions from a static high-level setting to a dynamic adjustment that responds to real-time braking conditions. The controller modulates the clutch capacity to match the instantaneous negative wheel torque command, ensuring torque hole prevention only when necessary while maximizing energy recapture during light braking events.
Solution Approach 2:
The system dynamically changes the bypass clutch torque capacity parameter based on the magnitude of negative wheel torque commands. This parameter adjustment allows the system to maintain sufficient torque capacity to prevent torque holes during hard braking while reducing capacity during light braking to maximize energy recapture efficiency.
3Ease of operation
If the bypass clutch is not adjusted during regenerative braking, then the system is simple to operate, but energy waste occurs and fuel economy is reduced
Solution Approach 1:
The control system automatically adjusts the bypass clutch torque capacity based on real-time wheel torque commands without requiring manual intervention. The controller continuously monitors braking conditions and self-adjusts the clutch capacity, maintaining simplicity of operation while eliminating energy waste through automated optimization.
Solution Approach 2:
The system automatically changes the bypass clutch torque capacity parameter in proportion to negative wheel torque commands during regenerative braking events. This automated parameter adjustment eliminates the need for complex manual control while maximizing energy recapture and preventing energy waste.
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 solution enhances fuel economy by optimizing energy recapture during braking, preventing torque holes and reducing energy waste, thereby improving vehicle efficiency and drivability.
Implementation Method 1
a generator converts the kinetic energy of the vehicle into electrical energy which is then used to power various subsystems or is stored a battery
Implementation Method 2
a torque converter bypass clutch, disposed between an electric machine and a drive wheel
Data Source
AI summary
A vehicle includes an electric machine, battery, torque converter bypass clutch, drive wheel, and controller. The electric machine is configured to recharge the battery via regenerative braking. The torque converter bypass clutch is disposed between the electric machine and the drive wheel. The controller is programmed to, in response to a negative drive wheel torque command during a regenerative braking event, adjust a closed-state torque capacity of the torque converter bypass clutch based on the torque command.