Compact Electric Drive System Using Nested Oil Pan Housing
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Solution Overview
Problem
Existing supplemental electric drive systems in hybrid internal combustion-electric powertrains have limited operating cycle times and require significant space, making them unsuitable for sustained operation within the constraints of a vehicle.
Innovation Solution
A compact electric drive system is designed, incorporating a housing formed from an engine oil pan, with a main shaft, output shaft, electric motor, and dual planetary gear sets for efficient power transmission and reduced size, utilizing engine oil as lubricant and liquid-cooled stators for the motor, allowing for sustained operation and space efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a supplemental electric drive system is designed for sustained operation, then the operating cycle time is extended, but the space requirements increase
Solution Approach 1:
The patent applies nesting by placing the electric motor within the housing formed from the engine oil pan. The motor is positioned inside the existing oil pan structure, utilizing the space that would otherwise be unused. This allows the drive system to operate for extended periods while minimizing the additional space required in the vehicle.
Solution Approach 2:
The housing serves multiple functions: it forms the structural enclosure for the drive system components and simultaneously acts as the engine oil pan for lubrication. This multi-functionality reduces the total space required by eliminating the need for a separate oil pan structure.
2Volume of moving object
If a compact design is used to minimize space, then the volume is reduced, but the operating cycle time is limited
Solution Approach 1:
The electric motor and gear sets are nested within the housing formed from the engine oil pan. This nesting arrangement maximizes the use of available space while maintaining adequate clearance for heat dissipation and component operation, enabling both compact size and sustained operation.
Solution Approach 2:
The housing acts as an intermediary structure that provides both structural support and thermal management. By forming the housing from the engine oil pan, the system utilizes the existing cooling and lubrication infrastructure to support extended operation in a compact package.
3Productivity
If dual planetary gear sets are used for efficient power transmission, then the speed reduction ratio is improved, but the device complexity increases
Solution Approach 1:
The transmission system is segmented into two distinct planetary gear sets, each providing a specific speed reduction ratio. The first planetary gear set reduces speed from the motor to an intermediate level, while the second planetary gear set provides further reduction to the final output. This segmentation allows for optimized power transmission at each stage while maintaining modular construction.
Solution Approach 2:
Both planetary gear sets are integrated within a single housing structure, sharing common mounting points and lubrication systems. This merging of the two gear sets into one compact unit reduces overall complexity compared to having separate transmission assemblies, while still achieving the desired cumulative speed reduction ratio.
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 compact design enables extended operating cycles while minimizing space requirements, enhancing the vehicle's powertrain efficiency and operational capabilities, such as torque vectoring and independent wheel control.
Implementation Method 1
The first planetary gear set is centered on the axis and provides a first speed reduction ratio between the rotor and a second planetary gear set
Implementation Method 2
The second planetary gear set provides a second speed reduction ratio between the first planetary gear set and the output shaft
Implementation Method 3
liquid-cooled stators for the motor
Data Source
AI summary
A drive unit includes a housing, a main shaft, an output shaft, an electric motor, a first planetary gear set, and a second planetary gear set. The main shaft is rotatably disposed in the housing, and with the housing cooperatively defines an axis of rotation. The output shaft is disposed at least in part in the housing and is rotatable about the axis. The electric motor is disposed in the housing and has a rotor centered on and rotatable about the axis. The first planetary gear set is centered on the axis and provides a first speed reduction ratio between the rotor and a second planetary gear set. The second planetary gear set provides a second speed reduction ratio between the first planetary gear set and the output shaft.