Electric Motor Torque Control via Accelerator Pedal Speed

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Solution Overview

Problem

Existing output torque control systems for electric motors in vehicles fail to differentiate between rapid and moderate acceleration modes, leading to inadequate vehicle acceleration according to driver requirements.

Innovation Solution

An output torque control system that includes an electric motor, a depressing speed detection unit, and a control unit with acceleration modes (normal and rapid acceleration modes) to adjust output torque based on detected depressing speed and vehicle speed, allowing for tailored torque control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the output torque control system uses a single torque increase pattern for all acceleration scenarios, then the control system is simple to implement, but the vehicle cannot be accelerated as desired by the driver in different driving conditions

Engineering Contradiction:
Improveacceleration adaptabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the acceleration control into multiple distinct modes (normal acceleration mode and rapid acceleration mode) based on accelerator pedal depressing speed. This segmentation allows the system to provide different torque increase patterns for different driving conditions, improving adaptability without requiring a completely complex new control architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control system dynamically switches between different torque control patterns based on real-time detection of accelerator pedal depressing speed. This dynamic adaptation enables the system to respond appropriately to varying driver intentions and driving conditions, resolving the contradiction between simplicity and adaptability.

Inventive Principle:
Principle #15Dynamics

2Speed

If the output torque increases rapidly at low vehicle speeds, then the vehicle can accelerate quickly from stationary position, but it may cause excessive torque and potential damage during startup

Engineering Contradiction:
Improvevehicle acceleration speedVSAvoidexcessive torque at low speed
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent applies different torque control characteristics to different vehicle speed ranges. At low speeds, the system uses a more conservative torque increase pattern, while at higher speeds, it allows for more aggressive torque application. This localized adaptation prevents harmful effects at startup while maintaining good acceleration performance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The control system performs preliminary assessment of the driving situation by detecting accelerator pedal depressing speed before applying full torque. This preliminary action allows the system to prepare appropriate torque control patterns in advance, preventing excessive torque application at low speeds while readying for rapid acceleration when appropriate.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the output torque control system responds equally to the same accelerator pedal depression regardless of current vehicle speed, then the control logic is simple, but the acceleration performance does not match driver expectations in different speed ranges

Engineering Contradiction:
Improvedriver acceleration controlVSAvoidvehicle acceleration performance
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The system continuously monitors vehicle speed and accelerator pedal depressing speed, using this feedback to dynamically adjust the torque control pattern. This feedback mechanism ensures that the vehicle responds appropriately to driver input across different operating conditions, matching driver expectations while maintaining reasonable control complexity.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2497679B1Output torque control system
Publication Date: 2018.09.05 MITSUBISHI MOTORS CORP
  • EP2497679B1 patent drawingFigure 1
  • EP2497679B1 patent drawingFigure 2
  • EP2497679B1 patent drawingFigure 3

AI summary

An output torque control system includes a control unit (80) which includes an acceleration mode detection unit (50) and an output torque control unit (23). The acceleration mode detection unit (50) selects a normal acceleration mode which includes output torque information indicating an increased amount of output torque of an electric motor (4) as time elapses or a rapid acceleration mode which includes output torque information indicating the increased amount of output torque of the electric motor (4) as time elapses more largely than in the normal acceleration mode based on a result of a detection by a depressing speed detection unit (50). The output torque control unit (23) selects one of the output torque information which corresponds to the result of the detection by the acceleration mode detection unit (50) to control the output torque produced by the electric motor (4) based on the selected output torque information.