Motor-Assisted Double Clutch Transmission Shift Control
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Solution Overview
Problem
Double clutch transmission systems face issues with clutch damage, energy loss due to clutch slip, and safety concerns during hill-starts, along with strong shift shocks due to thermal capacity limitations, which affect the efficiency and safety of power delivery in vehicles.
Innovation Solution
A power transmitting apparatus is introduced that incorporates a motor/generator and a planetary gear set into a double clutch transmission system, enabling smooth starts and quick shifts, regenerative braking, and start charging, while improving fuel economy and safety by using a motor/generator to assist in shifting even when the engine is stopped.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a double clutch transmission system is used to achieve quick shifts, then shift speed is improved, but clutch damage and energy loss due to clutch slip occur
Solution Approach 1:
A motor/generator is introduced as an intermediary device between the engine and transmission system. During shift operations, the motor/generator provides torque assistance to reduce clutch slip and minimize energy loss while maintaining quick shift capability. The motor/generator acts as a mediator that compensates for the inherent energy losses in the clutch system.
Solution Approach 2:
The system dynamically changes operational parameters by switching between engine-driven mode and motor/generator-assisted mode. During shift operations, the control system adjusts the torque contribution from the motor/generator to optimize clutch slip reduction, thereby changing the energy distribution parameters in real-time to minimize losses while maintaining shift speed.
2Speed
If clutch thermal capacity is limited to control shift time, then shift speed is improved, but shift shock increases
Solution Approach 1:
The motor/generator serves as a mediator that smooths torque transitions during shift operations. By providing auxiliary torque and controlling the rate of torque transfer, the motor/generator reduces shift shock while maintaining quick shift capability, effectively decoupling the relationship between shift speed and shift shock.
Solution Approach 2:
The control system anticipates shift operations and pre-charges the motor/generator to provide torque assistance before the actual shift occurs. This beforehand cushioning of torque support prevents sudden torque drops that cause shift shock, while still achieving quick shift times.
3Use of energy by moving object
If the engine is stopped to improve fuel economy, then fuel consumption is improved, but shifting capability is reduced
Solution Approach 1:
The motor/generator is designed to provide multiple functions including propulsion, regenerative braking, and shift assistance. When the engine is stopped, the motor/generator can independently assist or perform shifting operations, making the system self-sufficient and eliminating the trade-off between fuel economy and shifting capability.
Solution Approach 2:
The motor/generator is engineered as a multi-functional component that can operate in motor mode for propulsion and shift assistance, and in generator mode for regenerative braking. This universality allows the system to maintain full shifting capability even when the engine is stopped, thereby improving fuel economy without sacrificing operational capability.
4Use of energy by moving object
If regenerative braking is implemented to improve fuel economy, then fuel consumption is improved, but system complexity increases
Solution Approach 1:
The motor/generator is designed to perform multiple functions including propulsion, regenerative braking, and shift assistance within a single integrated component. By consolidating these functions into one universal device rather than separate systems, the patent actually reduces overall system complexity while achieving regenerative braking capability and improved fuel economy.
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
The solution enhances fuel economy, minimizes clutch slip and energy loss, improves shift smoothness, and ensures driving safety by utilizing the motor/generator for power assistance, allowing for secure shifting and reduced wear on friction members.
Implementation Method 1
a motor/generator operated as a motor or a generator
Implementation Method 2
a planetary gear set including a first rotation element directly connected to the motor/generator, a second rotation element directly connected to the third input shaft, and a third rotation element directly connected to the first input shaft
Implementation Method 3
clutch damage and energy loss due to clutch slip
Data Source
AI summary
A power transmitting apparatus may include a first input shaft to selectively receive torque of an engine, a second input shaft to selectively receive the torque of the engine and having at least one input gear, a third input shaft selectively connected to the second input shaft and having at least one input gear, a motor/generator operated as a motor or a generator, a planetary gear set including a first rotation element directly connected to the motor/generator, a second rotation element directly connected to the third input shaft, and a third rotation element directly connected to the first input shaft, a first speed output unit adapted to convert torque input from the second input shaft or the third input shaft and output the converted torque, and a second speed output unit to convert torque input from the second input shaft or the third input shaft and output the converted torque.