EV Launch Control with Staged Torque for Grip-Limited Acceleration
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Solution Overview
Problem
Existing electric vehicles lack effective launch control systems to achieve rapid acceleration from a standstill, which is crucial for high-performance driving experiences.
Innovation Solution
A launch control system and method that includes an AVN system for selecting road grip level and launch control activation, an accelerator and brake pedal detector, and a vehicle controller to execute staged launch controls, applying pre-motor torque and boost modes to optimize acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If maximum torque is output from the start of launch, then instantaneous acceleration is achieved, but wheel slip and loss of traction occur on low-grip surfaces
Solution Approach 1:
The system performs preliminary actions by pre-charging the battery and pre-heating the motor before launch. This prepares the powertrain to deliver maximum torque immediately when needed, while the control system pre-calculates optimal torque curves based on detected road grip conditions, allowing instantaneous acceleration without wheel slip.
Solution Approach 2:
The launch control system dynamically adjusts the motor torque output based on real-time detection of road grip levels. The controller continuously monitors wheel speed, vehicle speed, and acceleration to determine the current drive state, and dynamically modifies the torque command to maintain optimal traction while maximizing acceleration performance across varying road conditions.
2Speed
If launch control systems are added to electric vehicles, then high-performance acceleration is achieved, but system complexity increases
Solution Approach 1:
The vehicle controller performs multiple functions: it controls motor torque output, manages battery power delivery, detects drive state through various sensors, and executes launch control algorithms. By consolidating these functions into a single controller rather than adding separate dedicated systems, the patent achieves high-performance launch control while minimizing the increase in overall system complexity.
Solution Approach 2:
The launch control system uses sensors already present in the vehicle (wheel speed sensors, accelerator pedal position sensors, brake pedal position sensors) to detect drive state and road grip conditions. The system serves itself by utilizing existing infrastructure rather than requiring entirely new sensing systems, thereby reducing complexity while achieving sophisticated launch control.
3Productivity
If staged launch control is implemented, then optimal acceleration performance is achieved, but control algorithm complexity increases
Solution Approach 1:
The launch control process is segmented into distinct stages: a first stage for initial torque application and a second stage for optimized acceleration. This segmentation allows the control algorithm to use different torque curves and control strategies for each stage, optimizing acceleration performance while keeping each individual stage's control logic relatively simple and manageable.
Solution Approach 2:
The system optimizes acceleration performance by changing key parameters during the launch process, including motor torque output, battery current limits, and torque curve characteristics. The controller adjusts these parameters based on detected road grip levels and vehicle state, allowing optimal performance across different conditions without requiring excessively complex algorithms.
Data Source
AI summary
A launch control system and method for an electric vehicle, which are capable of satisfying a driver's demand for a high-performance vehicle by realizing the high performance of the electric vehicle. The system and method maximize acceleration at an initial stage of launching the electric vehicle from a standstill, thereby shortening the time to reach the maximum acceleration when launching the electric vehicle from the standstill.