Hybrid Transmission Module Segmentation for Weight Reduction
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Solution Overview
Problem
Current hybrid automatic transmissions are overly complex, leading to increased size, weight, and cost, which can negatively impact fuel economy and efficiency due to unnecessary complexity and over-capacitization.
Innovation Solution
A multi-speed hybrid automatic transmission design featuring a hybrid module with an electric motor underdriven by a module planetary gear set, a disconnect clutch, a launch clutch, and a vibration absorber, coupled with a gearbox containing three planetary gear sets and five torque transmitting devices to generate six forward speed ratios and reverse, allowing for electric-only, hybrid, and battery charging modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple electric motors, compound planetary gear sets and over six clutches or brakes are used in hybrid automatic transmissions, then the transmission can provide complex propulsion modes and high performance, but the device complexity, size, and weight increase significantly
Solution Approach 1:
The transmission is divided into two independent modules: a hybrid module containing a single electric motor with a simple planetary gear set and two clutches, and a conventional gearbox module with three planetary gear sets and five torque transmitting devices. This segmentation allows each module to be optimized independently, reducing overall complexity while maintaining versatility through modular combination.
Solution Approach 2:
The patent merges a hybrid electric powertrain with a conventional automatic transmission by coupling the hybrid module output to the gearbox input through a launch clutch. This combination allows the system to leverage the simplicity of conventional transmissions while adding hybrid capabilities, avoiding the need for completely new complex hybrid transmission designs.
2Adaptability or versatility
If multiple electric motors, compound planetary gear sets and over six clutches or brakes are used in hybrid automatic transmissions, then the transmission can provide complex propulsion modes, but the manufacturing cost increases
Solution Approach 1:
By segmenting the transmission into a hybrid module and a conventional gearbox module, the patent enables independent manufacturing and assembly of each module. This reduces development costs for each module and allows standardization of the gearbox portion, which can be produced using conventional manufacturing processes, thereby reducing overall manufacturing cost.
Solution Approach 2:
The patent employs conventional off-the-shelf components where possible, such as standard planetary gear sets and clutch assemblies, rather than designing custom components. This approach leverages existing manufacturing infrastructure and supply chains, reducing development and tooling costs.
3Adaptability or versatility
If multiple electric motors, compound planetary gear sets and over six clutches or brakes are used in hybrid automatic transmissions, then the transmission can provide complex propulsion modes, but the overall size and weight increase, cutting into fuel economy savings
Solution Approach 1:
The segmentation into two modules allows the hybrid module to be compact and lightweight, containing only one electric motor and a simple planetary gear set. The heavier gearbox module uses conventional components that can be optimized for strength-to-weight ratio. This modular approach minimizes total weight compared to integrated hybrid transmission designs.
Solution Approach 2:
The patent extracts the electric motor from the main transmission housing and places it in a separate hybrid module, allowing the gearbox to maintain its conventional compact design. This separation removes the need for the gearbox to accommodate multiple motors and complex control mechanisms, reducing overall size and weight.
4Adaptability or versatility
If multiple electric motors, compound planetary gear sets and over six clutches or brakes are used in hybrid automatic transmissions, then the transmission can provide complex propulsion modes, but the unnecessary complexity reduces fuel economy
Solution Approach 1:
The modular segmentation reduces the number of torque transmitting devices needed in each module, simplifying the control logic and reducing mechanical losses from friction and inefficiency. The hybrid module uses only two clutches instead of over six, reducing parasitic losses and improving overall system efficiency.
Solution Approach 2:
The conventional gearbox module can operate independently of the hybrid module, using its own five torque transmitting devices to provide six forward speed ratios and reverse. This self-sufficiency allows the gearbox to be optimized for mechanical efficiency without the added complexity of integrated electric motor control, improving fuel economy during engine-only operation.
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 design reduces the overall size and weight of the transmission while maintaining performance, improving fuel economy by enabling efficient propulsion modes and reducing unnecessary complexity.
Implementation Method 1
the hybrid module includes an electric motor underdriven by a module planetary gear set
Implementation Method 2
a vibration absorber coupled for common rotation with the launch clutch
Data Source
AI summary
A transmission includes input and output shafts, a hybrid module coupled to the input shaft and a gearbox coupled to the module and output shaft. The hybrid module includes an electric motor under driven by a gearset; a disconnect clutch coupled to the gearset and selectively to the input shaft; a launch clutch coupled to the disconnect clutch and selectively to a module output; and a vibration absorber coupled with the launch clutch. The gearbox includes three gearsets and five torque transmitting devices operable to generate six forward speeds and reverse. One torque transmitting device is a clutch brake applied with a piston that reaches over a park gear, and another one is a selectable one way clutch. Two of the torque transmitting devices are rotating clutches that are radially stacked. The transmission includes an electric only mode, a hybrid mode and a battery charging mode.