Electric Drivetrain Brake Threshold Control for Emergency Torque Cutoff

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The electrification of work machines has rendered mechanical torque transmission interruptions impossible, and the control behavior differs from internal combustion engine-driven machines, necessitating a method to ensure safe torque transmission interruption during emergency braking without undesired interruptions.

Innovation Solution

A method to control an electric drivetrain by determining a brake pedal actuation distance and duration exceeding thresholds, and generating a control signal to disable torque generation if no drive torque maintaining conditions are met, ensuring safe and quick stops.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical clutch is used for torque transmission interruption, then emergency braking safety is improved, but device complexity increases and electrification compatibility deteriorates

Engineering Contradiction:

Improveemergency braking safetyVSAvoidmechanical clutch structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical clutch system with an electronic control system that manages torque generation through electrical signals. The control device monitors brake pedal actuation and selectively disables torque generation by the electric drivetrain, eliminating the need for mechanical torque transmission interruption components while achieving the same safety function in electrified work machines.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the essential function of torque transmission interruption from the mechanical clutch and implements it through a simplified control logic that disables torque generation electronically. This removes the complex mechanical clutch structure while retaining the critical safety function of preventing torque transmission during emergency braking.

Inventive Principle:

Principle #2Taking out (Extraction)

2Loss of energy

If brake is applied frequently for energy recuperation, then energy efficiency is improved, but undesired torque transmission interruption increases

Engineering Contradiction:

Improveenergy recuperation efficiencyVSAvoidtorque transmission stability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent applies partial action by implementing threshold-based detection for brake pedal actuation. Instead of responding to all brake applications, the system only disables torque generation when the brake pedal actuation exceeds specific thresholds (actuation distance and actuation duration). This allows normal braking for energy recuperation to continue uninterrupted while still providing torque transmission interruption for genuine emergency situations.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent changes the parameters for triggering torque transmission interruption from any brake application to specific parameter thresholds (actuation distance threshold value and actuation duration threshold value). By monitoring these parameters, the system distinguishes between normal braking (energy recuperation) and emergency braking, enabling energy efficiency improvements without compromising torque transmission stability.

Inventive Principle:

Principle #35Parameter changes

3Speed

If torque generation is disabled during emergency braking, then stopping distance is improved, but operational comfort deteriorates

Engineering Contradiction:

Improvestopping speedVSAvoidoperational comfort

Core Design Contradiction:

SpeedVSEase of operation

Solution Approach 1:

The patent applies partial action by selectively disabling torque generation only when brake pedal actuation exceeds defined thresholds. This selective approach ensures that torque generation is interrupted during genuine emergency braking situations (improving stopping distance) while maintaining normal torque generation during routine operations (preserving operational comfort).

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent implements feedback through continuous monitoring of brake pedal actuation parameters (actuation distance and actuation duration). The control device uses this feedback to determine whether to disable torque generation, ensuring that operational comfort is maintained during normal braking while enabling rapid stopping when emergency conditions are detected through threshold exceedance.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20250257550A1Method for controlling an electric drivetrain of a work machine, and corresponding control device

Publication Date: 2025.08.14 ZF FRIEDRICHSHAFEN AG

AI summary

A method of controlling an electric drivetrain of a work machine, the method including determining whether a brake pedal actuation has occurred with an actuation distance greater than an actuation distance threshold value for an actuation duration longer than an actuation duration threshold value. The method further includes determining whether no drive torque maintaining condition exists, based on a determination that the brake pedal actuation occurred with the actuation distance greater than the actuation distance threshold value for the actuation duration longer than the actuation duration threshold value. The method further includes generating a control signal for the electric drivetrain to disable a torque generation by the electric drivetrain based on a determination that no drive torque maintaining condition exists.