Electric Vehicle Driving System with Segmented Gear Shifts
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Solution Overview
Problem
Electric vehicles require efficient power transfer to maximize climbing ability and top speed while minimizing motor volume and reducing shift shock, which existing technologies have not adequately addressed.
Innovation Solution
A driving system for electric vehicles that includes a motor, a shift assembly with multiple meshed external gear pairs, a clutch for intermittent power transfer, a gear lever with position sensors, and a controller to manage gear shifts and clutch engagement, allowing for smooth and efficient power transfer and gear changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a transmission with multiple gear shifts is added to reduce motor volume, then motor volume is reduced and driving distance per power unit is increased, but device complexity increases
Solution Approach 1:
The transmission system is segmented into discrete gear pairs (first gear pair, second gear pair, etc.) with specific transmission ratios, allowing the motor to operate at optimal speeds across different vehicle speed ranges. This segmentation enables the motor to be smaller while maintaining efficiency through gear multiplication.
Solution Approach 2:
The transmission assembly serves multiple functions: power delivery to driving wheels, motor speed multiplication, and operational mode selection (forward/reverse/neutral). The clutch assembly similarly handles multiple tasks including engagement/disengagement and mode transitions, reducing the need for separate dedicated components.
2Loss of energy
If a transmission system is designed to maximize power transfer efficiency, then power loss is reduced, but shift shock may occur during gear changes
Solution Approach 1:
The controller pre-coordinates clutch engagement/disengagement timing with gear shift operations. Before a gear shift occurs, the clutch is disengaged to disconnect the motor from the transmission, allowing the gear pairs to shift without load. This preliminary action prevents shock transmission to the drivetrain while maintaining power transfer efficiency during steady-state operation.
Solution Approach 2:
The system dynamically adjusts clutch engagement states based on operational requirements. The clutch transitions between engaged and disengaged states in coordination with gear shifts, and the controller manages torque delivery dynamically to smooth transitions. This dynamic control eliminates shift shock while preserving high power transfer efficiency during gear-driven operation.
3Adaptability or versatility
If a clutch is added to enable intermittent power transfer and mode selection, then operational versatility is improved, but device complexity increases
Solution Approach 1:
The clutch assembly is designed as a multi-functional component that handles both power delivery (engaged state) and mode selection (disengaged state for reverse/neutral). This universal design eliminates the need for separate clutches for different functions, reducing overall system complexity while maintaining operational versatility.
Solution Approach 2:
The controller receives feedback from position sensors that detect gear lever position and coordinates clutch engagement/disengagement accordingly. This feedback mechanism automates the complex sequencing of clutch and gear operations, simplifying the control interface for the driver while managing the complexity of coordinated actuator control internally.
4Ease of operation
If position sensors and actuators are added to enable automated gear shift control, then ease of operation is improved, but device complexity increases
Solution Approach 1:
Position sensors provide continuous feedback on gear lever position to the controller, enabling automated detection of driver intent and coordination of clutch and shift actuator operations. This feedback loop simplifies the driver's task to merely moving the gear lever while the control system manages the complex sequencing of multiple actuators, effectively trading mechanical complexity for electronic control intelligence.
Solution Approach 2:
The control system automatically manages the coordination between gear lever position, clutch engagement state, and gear pair selection without requiring direct driver intervention for each parameter. The system serves itself by using sensor feedback to autonomously determine the appropriate clutch and actuator commands, reducing the operational burden on the driver while managing internal complexity through integrated control logic.
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 system reduces motor volume, increases driving distance per electric power unit, and eliminates shift shock, providing a practical and economical solution for electric vehicle propulsion.
Implementation Method 1
a position sensor configured to detect the assigned positions to which the gear lever sequentially moves, on the basis of continuous changes in physical quantities... The position sensor may include a contactless magnetic flux sensor not in direct contact with the gear lever, with magnetic flux density thereof continuously changing in a response to a displacement of the gear lever.
Data Source
AI summary
A driving system for an electric vehicle may include a shift assembly receiving power from a motor, and providing a plurality of shift gears using a plurality of meshed external gear pairs, a clutch intermittently transferring power from the motor to the shift assembly, a gear lever allowing a driver to sequentially select a plurality of assigned positions that are discontinuously disposed, a position sensor detecting the assigned positions to which the gear lever sequentially moves, on the basis of continuous changes in physical quantities, a clutch actuator actuating the clutch, a shift actuator actuating the shift assembly to change gear shifts, and a controller configured for controlling the clutch actuator, the shift actuator, and the motor to change gear shifts by receiving signals from the position sensor.