EV Driving Mode Switching Based on Steering Wheel Grip

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Solution Overview

Problem

In battery electric vehicles, unintended mode switching between motor driving and gear shift driving modes can cause delays in driver response, leading to unexpected vehicle behavior.

Innovation Solution

A controller is programmed to permit switching between motor driving and gear shift driving modes when the steering wheel is gripped, and also allows switching when the vehicle is stopped or the shift position is in neutral, or the pseudo-clutch pedal is depressed, ensuring minimal changes in vehicle behavior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If mode switching is permitted at any time, then switching convenience is improved, but driver response delay increases due to unintended switching

Engineering Contradiction:
Improvemode switching convenienceVSAvoiddriver response delay
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The system changes the parameter of mode switching availability based on the detected steering wheel grip state. When the steering wheel is detected as gripped, mode switching is permitted; when not gripped, switching is restricted. This dynamic parameter change resolves the contradiction by allowing convenient switching only when the driver is actively controlling the vehicle.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system uses feedback from the steering wheel grip detection to control mode switching permission. The grip detection unit continuously monitors the steering wheel state and provides feedback to the control unit, which then enables or disables mode switching accordingly. This feedback mechanism prevents unintended switching while maintaining convenience when needed.

Inventive Principle:
Principle #23Feedback

2Loss of time

If mode switching is restricted only when steering wheel is gripped, then driver response delay is reduced, but switching opportunity decreases when vehicle is stopped

Engineering Contradiction:
Improvedriver response delayVSAvoidmode switching opportunity
Core Design Contradiction:
Loss of timeVSEase of operation

Solution Approach 1:

The system dynamically adjusts the mode switching permission based on vehicle operating conditions. During vehicle operation, switching is restricted to when the steering wheel is gripped. However, when the vehicle is stopped, the system dynamically changes the permission state to allow switching even without steering wheel grip, adapting to the different operational context.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the switching permission parameter based on vehicle stop/detect status. When the vehicle is detected as stopped, the permission parameter is changed to allow mode switching without steering wheel grip requirement. This parameter change increases switching opportunities during stationary periods without compromising safety during operation.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If mode switching is permitted during neutral range, then switching convenience is improved, but vehicle behavior stability may be affected

Engineering Contradiction:
Improvemode switching convenienceVSAvoidvehicle behavior stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The system changes the mode switching permission based on the shift position parameter. When the shift position is detected as being in the neutral range, the system permits mode switching. This parameter-based control allows convenient switching during neutral operations while the system manages torque output to maintain acceptable vehicle behavior stability.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4427967A1Battery electric vehicle
Publication Date: 2024.09.11 TOYOTA JIDOSHA KK
  • EP4427967A1 patent drawingFigure 1
  • EP4427967A1 patent drawingFigure 2~4
  • EP4427967A1 patent drawingFigure 5

AI summary

A battery electric vehicle (20) includes a motor (32) configured to output torque for driving to a drive shaft, a mode selector (68) configured to select a driving mode from a plurality of driving modes based on driver's operation including a motor driving mode that the battery electric vehicle is driven by outputting a required torque required for driving from the motor and a gear shift driving mode that the battery electric vehicle is driven with behavior of torque output from the motor as behavior of the torque in an engine vehicle including an engine and a transmission based on the driver's shift operation, and a controller (50) programmed to control the motor such that the battery electric vehicle drives in the driving mode selected by the mode selector. The controller is programmed to permit switching between the motor driving mode and the gear shift driving mode when a steering wheel is gripped.