Hybrid Drive Train Second Electric Machine Merging Starter and Auxiliary Functions
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Solution Overview
Problem
Existing hybrid drive trains for hybrid vehicles face challenges in optimizing installation space, weight, and cost due to the need for multiple electric machines and wraparound drives, which increase complexity and drag losses.
Innovation Solution
A hybrid drive train design where the second electric machine has a dual function, capable of starting the internal combustion engine and driving auxiliary units independently of the output shaft, eliminating the need for additional electric machines and wraparound drives by using a mechanical coupling without traction mechanisms, allowing for efficient operation and reduced parts and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple electric machines and wraparound drives are used to drive auxiliary units, then the functionality and reliability are improved, but the device complexity, installation space, and weight increase
Solution Approach 1:
The patent combines the functions of starting the internal combustion engine and driving auxiliary units into a single second electric machine. This electric machine is mechanically coupled to both the output shaft of the internal combustion engine and the auxiliary units, eliminating the need for separate wraparound drives and reducing system complexity while maintaining all necessary functionalities.
Solution Approach 2:
The second electric machine is designed with multi-functionality, serving both as a starter motor for the internal combustion engine and as a driver for auxiliary units such as air conditioning compressors. This universal approach reduces the number of components needed while ensuring reliable operation across different vehicle states.
2Reliability
If multiple electric machines and wraparound drives are used, then the auxiliary units can be driven reliably, but the installation space and weight increase
Solution Approach 1:
The patent merges the drive functions for auxiliary units into the second electric machine that is already required for starting the internal combustion engine. By eliminating separate wraparound drives and associated components, the overall system weight is reduced while maintaining the ability to reliably drive auxiliary units when needed.
3Ease of operation
If wraparound drives are used to drive auxiliary units, then the auxiliary units can be driven, but drag losses increase and installation space is consumed
Solution Approach 1:
The patent extracts the auxiliary unit drive function from the wraparound drive system and integrates it directly into the second electric machine. This eliminates the intermediate wraparound transmission mechanism, removing the associated drag losses and energy inefficiencies while maintaining full drive capability for auxiliary units.
4Productivity
If the second electric machine drives the output shaft to start the engine, then the engine can be started, but the auxiliary units cannot be driven independently when the engine is off
Solution Approach 1:
The patent implements a dynamic mechanical coupling system where the second electric machine can selectively engage with either the output shaft for starting the internal combustion engine or the auxiliary units for independent operation. This dynamic configuration allows the system to adapt to different operational requirements, enabling auxiliary units to run independently when the engine is off while maintaining full starting capability when needed.
Data Source
AI summary
A hybrid drive train for a hybrid vehicle includes an internal combustion engine configured to drive the hybrid vehicle and an output shaft configured to provide torque to drive the hybrid vehicle, and a transmission which has a transmission input shaft. The hybrid drive train also includes a first electric machine by which the transmission input shaft can be driven, a second electric machine by which the output shaft can be driven to start the internal combustion engine, and an auxiliary unit configured to be driven by the second electric machine.