Electric Vehicle Powertrain with Bypass Clutch Mechanism
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Solution Overview
Problem
Existing powertrain systems for electric vehicles face challenges in efficiently transmitting power to driving wheels, leading to reduced vehicle range and performance, and lack a simple configuration for shift ratios between forward and reverse speeds, which increases motor capacity and weight, and does not allow for a neutral state that disconnects the motor from the wheels.
Innovation Solution
A powertrain configuration that includes an input shaft, an output shaft, first and second-speed gear mechanisms, a one-way clutch, a friction clutch, and a bypass mechanism to provide a shift ratio between advance and reverse second speeds, allowing for reduced motor capacity and weight, a neutral state, and improved fuel efficiency, without the need for a separate parking mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple speed reducer is used to transmit power from the motor to the driving wheels, then the configuration is simple, but the power transmission efficiency is reduced and vehicle range is limited
Solution Approach 1:
The power transmission system is segmented into multiple gear mechanisms (first-speed and second-speed gears) with different reduction ratios. This allows the system to divide the power transmission path into segments that can be selectively engaged based on driving conditions, improving overall transmission efficiency while maintaining reasonable system complexity
Solution Approach 2:
The system dynamically switches between different gear mechanisms (first-speed and second-speed) and transmission paths (forward and reverse) based on operating conditions. This dynamic adaptability allows the motor to operate at optimal efficiency points across different vehicle speeds and loads, significantly improving power transmission efficiency
2Power
If motor capacity is increased to provide sufficient power, then driving performance is improved, but vehicle weight increases
Solution Approach 1:
The system changes the transmission ratio parameter dynamically by switching between first-speed and second-speed gear mechanisms. This allows a smaller motor to achieve the same effective wheel torque by utilizing higher reduction ratios when needed, reducing motor size and vehicle weight while maintaining required power output
Solution Approach 2:
The gear mechanisms serve multiple functions: they provide both forward and reverse motion, multiple speed ratios, and torque multiplication. This multi-functionality eliminates the need for separate mechanisms for each function, allowing a compact motor design that meets all power requirements without excessive weight
3Adaptability or versatility
If forward and reverse second speeds are implemented, then driving versatility is improved, but the configuration becomes complex
Solution Approach 1:
The system merges forward and reverse transmission paths into a single integrated gear mechanism structure. The same first-speed and second-speed gear mechanisms are used for both forward and reverse directions, eliminating the need for separate forward and reverse gear sets. This reduces configuration complexity while maintaining full versatility for forward and reverse second speeds
4Reliability
If continuous power transmission is maintained, then the motor remains connected to driving wheels, but fuel efficiency is reduced
Solution Approach 1:
The system implements periodic engagement and disengagement of the friction clutch to create neutral states. During coasting or idle conditions, the clutch disengages to disconnect the motor from the driving wheels, reducing energy consumption. During acceleration or load conditions, the clutch engages to transmit power. This periodic action improves fuel efficiency while maintaining reliability when power is needed
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 configuration enables efficient power transmission, reduces motor capacity and vehicle weight, allows for a neutral state that disconnects the motor from the wheels, and improves fuel efficiency by implementing a parking function through interlocking of the input and output shafts, resulting in a more compact and lightweight powertrain system.
Implementation Method 1
a one-way clutch (OWC) mounted on a path along which power is transmitted from the input shaft (IN) to the output shaft (OUT) through the first-speed driving gear (D1) and the first-speed driven gear (P1)
Implementation Method 2
a friction clutch (CL) mounted to connect or disconnect a path along which the power is transmitted from the input shaft (IN) to the output shaft (OUT) through the second-speed driving gear (D2) and the second-speed driven gear (P2)
Implementation Method 3
a first-speed driving gear (D1) and a first-speed driven gear (P1) mounted on the input shaft (IN) and the output shaft (OUT), respectively, to be gear-meshed with each other
Data Source
AI summary
A powertrain for an electric vehicle, may include: an input shaft and an output shaft mounted in parallel to each other; first and second power transmission mechanisms provided to transmit power from the input shaft to the output shaft at two gear ratios different from each other; a one-way clutch included in the first power transmission mechanism; a friction clutch included in the second power transmission mechanism; and a bypass mechanism provided to form a power transmission path that bypasses the one-way clutch and a power transmission path that bypasses the friction clutch.