Hybrid Drive Vehicle Coupling Segmentation for Torque Management
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Solution Overview
Problem
Current hybrid drive vehicles with a disengagable coupling between the internal combustion engine and electric machine require a large, heavy, and expensive clutch to transmit maximum drive torque, leading to increased size and mechanical inertia, which hinders quick acceleration and is costly to produce.
Innovation Solution
A hybrid drive vehicle design featuring a disengagable coupling with a conically-shaped clutch and a shape coupling device, where the clutch is sized only for starting torque, and the shape coupling device handles the majority of torque transfer, reducing the size, weight, and cost of the coupling by using a commercially available gearbox component in a new position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a normal clutch is used to transmit maximum drive torque from the internal combustion engine, then the coupling can handle the full torque range, but the clutch becomes expensive, heavy and bulky with increased axial and radial dimensions
Solution Approach 1:
The coupling device is divided into two separate functional components: a clutch for torque transmission and a shape coupling device for mechanical engagement. This segmentation allows each component to be optimized for its specific function, with the clutch sized only for starting torque rather than maximum drive torque, significantly reducing its size and weight.
Solution Approach 2:
The shape coupling device provides mechanical engagement in a different dimensional approach, using axial movement and geometric shaping rather than relying solely on friction-based clutch surfaces. This allows torque transfer without requiring a large-friction-surface clutch.
2Reliability
If a normal clutch is used to transmit maximum drive torque, then the coupling is robust, but the radial development increases leading to high mechanical inertia that hinders quick acceleration
Solution Approach 1:
By separating the clutch function from the shape coupling device, the system reduces the rotational mass that needs to be accelerated. The clutch can be much smaller since it only handles starting torque, reducing the moment of inertia and improving acceleration response while the shape coupling device provides the necessary mechanical connection.
3Reliability
If a clutch sized for maximum drive torque is used, then the coupling can transmit full engine torque, but the production cost increases significantly
Solution Approach 1:
The separation of functions allows the clutch to be sized for the smaller starting torque requirement rather than maximum drive torque, significantly reducing material usage and manufacturing cost. The shape coupling device can be produced using standard gearbox components through axial movement and geometric shaping, further reducing costs.
4Weight of moving object
If the clutch size is reduced to match starting torque requirements, then weight and cost decrease, but the clutch alone cannot transmit maximum drive torque
Solution Approach 1:
The system merges two coupling mechanisms: a clutch for torque transmission during starting and a shape coupling device for mechanical engagement during torque transfer. This combination allows the clutch to be small (reducing weight) while the overall coupling system maintains full torque transmission capability through the shape coupling device.
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 reduces the coupling's size, weight, and production cost by over 60%, 70%, and 80% respectively, while maintaining efficient torque transfer and NVH performance, allowing for improved acceleration and cost-effectiveness.
Implementation Method 1
a conically-shaped clutch (26) which, in use, is suitable to transmit a starting torque generated by the electric machine (8) to the drive shaft (6)
Implementation Method 2
a shape coupling device (29) which, in use, is suitable to transfer the majority of a drive torque, generated by the internal combustion engine (5), from the drive shaft (6) to the shaft (10) of the electric machine (8)
Data Source
AI summary
A hybrid drive vehicle having: at least one driving wheel; an internal combustion engine provided with a drive shaft; an electric machine provided with its own shaft; a gearbox which transmits motion to the driving wheel; a disengagable coupling which acts as a synchroniser and is interposed, to establish a disconnectable mechanical connection, between the drive shaft and the shaft of the electric machine; and a transmission shaft interposed, to establish a permanent mechanical connection, between the shaft of the electric machine on the opposite side to the coupling and the gearbox.