EV Virtual Engine Speed Control Using Wheel Slip Switching
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Solution Overview
Problem
Existing electric vehicle systems fail to accurately simulate the virtual engine speed based on the operating state of the drive system, leading to a mismatch that can cause driver discomfort.
Innovation Solution
An electric vehicle with a controller that switches the output mode of the virtual engine speed between modes referencing front or rear wheel rotation speeds based on braking and slip ratios to match the vehicle's operating state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the virtual engine speed is calculated using a fixed reference (either front wheel or rear wheel rotation speed), then the calculation is simple, but the virtual engine speed may not match the actual operating state of the drive system
Solution Approach 1:
The patent applies the dynamics principle by making the reference selection for virtual engine speed calculation dynamic rather than fixed. The controller automatically switches between referencing front wheel rotation speed and rear wheel rotation speed based on the actual operating state (driving wheels identification), ensuring the virtual engine speed always matches the actual drive system state without requiring complex manual configuration
Solution Approach 2:
The patent applies parameter changes by switching the reference parameter (rotation speed source) based on operating conditions. When front wheels are driving wheels, the system uses front wheel rotation speed as reference; when rear wheels are driving wheels, it switches to rear wheel rotation speed. This dynamic parameter adjustment ensures accuracy while maintaining calculation simplicity
2Ease of manufacture
If the virtual engine speed does not match the operating state, then the system is simple to implement, but the driver experiences discomfort
Solution Approach 1:
The patent applies feedback by continuously monitoring the actual operating state (identifying which wheels are driving wheels) and using this information to adjust the virtual engine speed calculation reference. This closed-loop approach ensures the displayed virtual engine speed always corresponds to the actual drive system state, eliminating driver discomfort while keeping the system simple to implement
Data Source
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AI summary
A controller of an electric vehicle is configured to switch an output mode of a virtual engine speed between a first mode and a second mode in accordance with a predetermined condition. The first mode is an output mode in which the virtual engine speed is changed with reference to a wheel rotation speed of front wheels of the electric vehicle or a first rotation speed associated with the wheel rotation speed of the front wheels. The second mode is an output mode in which the virtual engine speed is changed with reference to a wheel rotation speed of rear wheels of the electric vehicle or a second rotation speed associated with the wheel rotation speed of the rear wheels.