Electric Traction System With Power Takeoff Unit
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Solution Overview
Problem
Heavy-duty trucks face significant fuel usage and emission issues due to idling and slow movement, particularly in staging areas, where conventional solutions like hybrid electric vehicles and power takeoff systems are either impractical or inefficient, as they require the internal combustion engine to operate continuously.
Innovation Solution
An electric traction system that includes an external electric motor powered by a hydrogen fuel cell, allowing the truck to operate without the internal combustion engine, with the motor acting as a generator during normal operation to recharge batteries, and using a power takeoff unit to transfer power to the transmission, enabling efficient movement at low speeds and reducing emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If an electric motor is used to power the transmission directly without ICE involvement, then fuel consumption and emissions are reduced, but the motor must be sufficiently powerful to handle heavy-duty truck loads which is challenging for conventional electric motors
Solution Approach 1:
The patent combines an electric motor with a conventional transmission system through a power take-off (PTO) interface. The electric motor and transmission work together in a hybrid configuration, allowing the motor to provide auxiliary power while the transmission handles the heavy-duty load requirements. This merging enables emission reduction without sacrificing the power handling capability needed for heavy-duty trucks.
Solution Approach 2:
The transmission system is designed to serve multiple functions: it can be powered by the ICE through conventional means, by the electric motor through the PTO interface, or by a combination of both. This multi-functionality allows the system to adapt to different operating conditions and load requirements while maintaining the ability to reduce emissions when appropriate.
2Stability of the object's composition
If a hybrid transmission with planetary gear set is used to transfer rotation from electric motor to transmission output shaft, then rotational load transfer is addressed, but the conventional transmission must be replaced which is impractical for trucks currently in service
Solution Approach 1:
The patent extracts the electric motor power transfer function from the main transmission body by using a separate power take-off (PTO) interface. Instead of integrating the motor into the transmission through complex planetary gear sets, the PTO interface provides a separate, modular connection point that allows the electric motor to drive the transmission output shaft independently. This extraction approach maintains the existing transmission while adding electric power capability.
Solution Approach 2:
The power transfer system is segmented into separate functional modules: the conventional transmission remains intact while a distinct PTO interface and electric motor assembly handle the electric power input. This segmentation allows the electric motor system to be added or removed independently without affecting the conventional transmission, facilitating easier manufacturing and deployment.
3Ease of manufacture
If a conventional PTO device is used to take power out of the ICE for inching operation, then the original transmission is preserved, but the ICE must operate full-time and power losses through hydraulic components are substantial
Solution Approach 1:
The patent replaces the hydraulic power transfer system with a direct mechanical connection through the PTO interface. Instead of using hydraulic pumps and motors to transfer power from the ICE to the transmission for inching operations, the electric motor connects directly to the transmission output shaft through the PTO, eliminating hydraulic components and their associated power losses. This mechanical substitution significantly improves energy efficiency.
4Ease of manufacture
If the electric motor is mounted externally to the transmission, then the transmission case structure is preserved, but the motor weight and size must be supported by external mounting structures
Solution Approach 1:
The patent incorporates the PTO interface into the transmission case design from the beginning, creating pre-prepared mounting points and alignment features that facilitate external electric motor installation. By planning the mounting structure in advance as part of the transmission case, the system avoids complex ad-hoc mounting solutions and reduces overall device complexity while preserving the transmission case structure.
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 system reduces fuel consumption and emissions by allowing trucks to operate electrically at low speeds without the internal combustion engine, improving efficiency and minimizing noise pollution in urban areas.
Implementation Method 1
An electric traction system includes an external electric motor powered by a hydrogen fuel cell
Implementation Method 2
An electric traction system includes an external electric motor powered by a hydrogen fuel cell
Data Source
Figure 1~1B
Figure 2
Figure 3A
AI summary
A drive train includes an internal combustion engine ("ICE") coupled to a transmission having a power takeoff port. A transfer device couples an electric motor to the transmission via the port. The electric motor is enabled in a certain configuration to selectively power the drive train during at least certain intervals when the ICE is powered off.