Hybrid Drive Unit Isolation for Reduced Electric Power Consumption
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Solution Overview
Problem
In hybrid vehicle drive units, the first motor/generator is often passively rotated during electric vehicle mode, leading to increased power loss and electric power consumption, necessitating counteractive torque generation, which further increases power consumption.
Innovation Solution
A drive unit design featuring a first differential mechanism connected to the engine and a second differential mechanism connected to the first motor, with engagement devices allowing selective disconnection to prevent torque transmission and thus prevent the first motor from rotating during electric vehicle mode, reducing electric power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the first motor/generator is passively rotated during EV mode, then the drive unit can operate in electric vehicle mode, but power loss increases
Solution Approach 1:
The drive unit is divided into two independent differential mechanisms (first and second) that can operate separately. The first differential mechanism can be disconnected from the second through the first engagement device, allowing the first motor to be isolated and prevented from passive rotation while the second motor operates in EV mode.
Solution Approach 2:
The first motor/generator is extracted from the mandatory torque transmission path by disconnecting the first differential mechanism from the second. This allows the first motor to be removed from the system during EV mode operation, eliminating its passive rotation and associated power losses.
2Object-affected harmful factors
If counteractive torque is generated by the first motor/generator to prevent passive rotation, then passive rotation is prevented, but electric power consumption increases
Solution Approach 1:
Instead of applying counteractive torque through the first motor, the solution extracts the first motor entirely from the torque transmission path by disconnecting the first differential mechanism. This eliminates both the harmful passive rotation and the need for counteractive torque generation.
Solution Approach 2:
The first engagement device acts as an intermediary that physically disconnects the first differential mechanism from the second differential mechanism. This mechanical intermediary prevents torque transmission to the first motor, eliminating passive rotation without requiring electrical counter-torque.
3Power
If the first differential mechanism is connected to the second differential mechanism, then torque can be transmitted between them, but the first motor rotates passively during EV mode
Solution Approach 1:
The connection between the first and second differential mechanisms is made dynamic rather than fixed. The first engagement device allows the system to switch between connected and disconnected states, enabling torque transmission when needed and isolation when the first motor would rotate passively.
Solution Approach 2:
The torque transmission path is segmented into two separate differential mechanisms that can be independently controlled. The first engagement device creates a controllable boundary between them, allowing selective connection to prevent passive rotation while maintaining torque transmission capability when required.
Data Source
AI summary
A drive unit is provided for hybrid vehicles capable of reducing electric power consumption during propulsion in an EV mode. The drive unit includes a first planetary gear unit to which an engine is connected, and a second planetary gear unit connected to a third rotary element of the first planetary gear unit. The drive unit includes a first engagement device that connects a first rotary element of the first planetary gear unit and a sixth rotary element of the second planetary gear unit, and a second engagement device that connects a fourth rotary element and the sixth rotary element of the second planetary gear unit.