Powertrain Torque Limiting for Smooth Dual-Pedal Vehicle Launch

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Solution Overview

Problem

During a standing start, when a driver simultaneously presses the accelerator and brake pedals, existing anti-slip systems in motor vehicles can cause jerky torque control, leading to slow vehicle movement and a negative driving experience due to excessive torque limitation and frequent activation of the Electronic Stability Program (ESP) anti-slip function.

Innovation Solution

A method and device for managing the powertrain that calculates a reference torque value based on the accelerator pedal pressure and adjusts it by limiting the torque when the brake pedal is pressed, allowing for a gradual recovery of torque as the brake is released, thereby avoiding excessive torque transmission and ESP activation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the ESP anti-slip function is activated to prevent wheel spin during standing start, then wheel traction is improved, but the vehicle acceleration becomes jerky and slow

Engineering Contradiction:

Improvewheel tractionVSAvoidvehicle acceleration

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The system detects dual pedal pressing (accelerator and brake simultaneously) before the brake is released, and pre-limits the torque command to a reduced value. This preliminary action prevents the torque spike that would occur when the brake is suddenly released, avoiding wheel spin and ESP activation while maintaining smooth vehicle launch.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the torque command is completely cut off to prevent wheel spin, then wheel traction is maintained, but the vehicle movement becomes minimal and driver experience deteriorates

Engineering Contradiction:

Improvewheel contact with roadVSAvoidvehicle movement

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Instead of completely cutting off the torque command, the system applies a partial limitation by reducing the torque to a predetermined lower value during dual pedal pressing. This partial action is sufficient to prevent wheel spin when the brake is released, while still allowing the vehicle to move forward smoothly and maintain driver satisfaction.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If the torque control is intermittently adjusted by ESP to maintain traction, then wheel slip is reduced, but driving comfort decreases due to jolts

Engineering Contradiction:

Improvewheel slip controlVSAvoiddriving comfort

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The system detects dual pedal pressing in advance and pre-limits the torque command before the brake is released. This preliminary torque limitation prevents wheel spin from occurring in the first place, eliminating the need for intermittent ESP corrections and the associated jolts, thereby ensuring smooth and comfortable vehicle launch.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP3856589B1Method for managing the drive train of a motor vehicle

Publication Date: 2023.10.25 STELLANTIS AUTO SAS

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AI summary

A method for managing the drive train (GMP) of a motor vehicle in response to pressure being applied to an accelerator control (20) by a driver of the vehicle, the method comprising a step (E2) of calculating a reference torque value (C0) translating the pressure applied to the accelerator control (20) and a step (E5) of transmitting a setpoint (C1) to the drive train (GMP) according to the reference torque value (C0), the method comprising, before the transmission step (E5), if pressure is applied to a brake control (21) by the driver, a step (E3) of limiting the reference torque value (C0) to a lower value constituting the setpoint (C1).