Hybrid Electric Traction Device with Decoupling Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hybrid vehicles face challenges in delivering high torque at low speeds while avoiding the need for a large, bulky, and expensive electric machine that can withstand high rotational speeds, as existing solutions require a compromise between torque and efficiency.
Innovation Solution
An electric traction device with a higher reduction ratio and a decoupling mechanism that allows the electric machine to disconnect from the wheels at high speeds, enabling high torque delivery at low speeds without exceeding the machine's maximum speed, using a transmission system with a dog clutch sleeve and electromagnetic control for gear engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a large electric machine with high power supply capacity is used to deliver high torque at low speeds, then the torque delivery capability is improved, but the device size, weight and cost increase
Solution Approach 1:
The patent applies a variable transmission ratio mechanism that dynamically changes the gear ratio between the electric machine and wheels based on vehicle speed. At low speeds, a high reduction ratio multiplies the electric machine's torque output. At high speeds, the transmission ratio is reduced or decoupled to prevent the electric machine from exceeding its maximum rotational speed rating. This dynamic adjustment allows a smaller electric machine to deliver high torque when needed without requiring oversized components.
Solution Approach 2:
The patent introduces a transmission system with variable ratio as an intermediary between the electric machine and the wheels. This transmission mechanism acts as a mediator that transforms the electric machine's rotational output into variable torque and speed outputs suitable for different driving conditions. The transmission includes planetary gear sets and clutch mechanisms that enable smooth ratio changes without directly coupling the electric machine to the wheels at all times.
2Force
If a high reduction ratio transmission is used to multiply torque at low speeds, then the torque delivery is improved, but the electric machine speed exceeds maximum limits at high vehicle speeds
Solution Approach 1:
The transmission system dynamically adjusts the reduction ratio based on operating conditions. At low vehicle speeds, a high reduction ratio (e.g., 10:1 or higher) multiplies the electric machine's torque output effectively. As vehicle speed increases, the transmission progressively reduces the ratio or disengages the electric machine from the drive wheels through clutch mechanisms, preventing the electric machine from exceeding its maximum safe rotational speed while maintaining torque delivery through the heat engine.
Solution Approach 2:
The system changes the transmission ratio parameter continuously or in discrete steps based on vehicle speed and torque demand. The control system monitors wheel speed and electric machine RPM, adjusting the transmission ratio to keep the electric machine operating within its optimal speed range while delivering required torque to the wheels. This parameter adjustment resolves the conflict between torque multiplication and speed limitation.
3Reliability
If the electric machine remains coupled to the wheels at high speeds, then the mechanical connection is maintained, but the electric machine operates inefficiently and suffers from excessive friction and inertia losses
Solution Approach 1:
The patent extracts or decouples the electric machine from the wheel drive system at high speeds using clutch mechanisms and transmission disengagement features. When vehicle speed exceeds a threshold and the heat engine can provide sufficient power alone, the transmission system disengages the electric machine from the final drive, removing it from the mechanical power transmission path. This eliminates friction and inertia losses in the electric machine's drivetrain connection while maintaining the option to re-engage when torque assistance is needed.
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 allows for efficient delivery of high torque at low speeds with a smaller electric machine, reducing the size and cost of the electrical installation and minimizing losses at high speeds by decoupling the electric machine, thus optimizing vehicle performance and reducing friction and inertia.
Implementation Method 1
said actuator being of the electromagnetic type
Data Source
Figure 1~3
Figure 4~5
AI summary
Electric traction device for hybrid vehicle comprising a thermal engine driving drive wheels by a first transmission, this electric traction device comprising an electric machine (10) driving wheels of the vehicle (18) by a second transmission (11, 31) independent of the first, following a single gear ratio, characterized in that this second transmission (11, 31) includes a drive decoupling device, and in that its gear ratio is such that the maximum permissible rotational speed of the electric machine corresponds to a speed significantly lower than the maximum speed of the vehicle.