Hybrid Clutch Torque Offloading Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Designers of hybrid powertrain transmission systems face challenges in developing torque-transmitting clutches that are large enough to handle required torque, manage temperature, meet durability and packaging constraints, and efficiently execute gear shifts while minimizing thermal energy impact on transmission performance.
Innovation Solution
A method and system that offloads torque from a currently engaged clutch by using a combination of electrical motors and an internal combustion engine to adjust output torque, with supplemental torque from an oncoming clutch, ensuring sufficient torque capacity and minimizing thermal effects during gear shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If clutch size is increased to transmit required torque and meet durability targets, then torque capacity and durability are improved, but packaging envelope and size constraints are worsened
Solution Approach 1:
The control system performs preliminary torque offloading from the current clutch before the shift occurs. By reducing the torque on the current clutch in advance and transferring it to the oncoming clutch, the system enables smaller clutch designs that wouldn't otherwise handle the full torque requirements, thus meeting torque capacity needs while reducing packaging envelope.
2Temperature
If clutch size is increased to manage temperature and meet durability targets, then thermal management capability is improved, but packaging envelope and size constraints are worsened
Solution Approach 1:
The control system performs preliminary torque offloading from the current clutch before the shift occurs. By reducing the torque on the current clutch in advance and transferring it to the oncoming clutch, the system enables smaller clutch designs that wouldn't otherwise handle the full torque requirements, thus meeting torque capacity needs while reducing packaging envelope.
3Reliability
If torque is offloaded from current clutch during gear shift, then shift smoothness and clutch durability are improved, but thermal energy generation during slippage may increase
Solution Approach 1:
The control system uses electrical motors to substitute for mechanical torque transfer during the shift process. By using electrical torque from the motors to replace mechanical torque from the clutch, the system minimizes clutch slippage and associated thermal energy generation while still achieving smooth torque transition and improved clutch durability.
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
Effectively enables smooth gear changes by optimizing torque distribution among electrical motors and the engine, enhancing clutch durability and reducing thermal impact on the transmission system.
Implementation Method 1
The first and second electrical machines comprise motor/generators operable to transform the electrical power to motive torque for input to the transmission
Implementation Method 2
The first and second electrical machines are operable to transform vehicle kinetic energy, transmitted through the vehicle driveline, to electrical energy potential that is storable in the electrical energy storage device
Implementation Method 3
An ongoing concern for designers of transmission devices is to develop torque-transmitting clutches that are sufficiently large enough to transmit required torque
Data Source
AI summary
A method and system to off-load motive torque from a clutch to execute a transmission shift is provided. The powertrain includes torque-generative devices operably connected to a two-mode, compound-split, hybrid electro-mechanical transmission. The method includes determining a commanded output torque, and a shift command. A first torque is transmitted by electrical motors, and is limited by their torque capacities. A supplemental motive torque is transmitted from an oncoming clutch. The supplemental motive torque is limited by a torque capacity of the oncoming clutch. Output torque of an internal combustion engine to the transmission is adjusted by an amount substantially equal to a difference between the commanded output torque and the first and the supplemental motive torques.