Hydrostatic Braking Mode Shift for ISO 3450 Compliance

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Solution Overview

Problem

Existing braking systems in heavy-duty vehicles with hydrostatic transmission do not meet the braking distance criteria of the ISO 3450 standard when operating in high-speed, low-torque mode, particularly for vehicles carrying heavy loads.

Innovation Solution

A method and control system that automatically activates a high-torque braking system by detecting a change in the speed-controller lever position from a high-speed, low-torque mode to a neutral position during braking, dynamically shifting to a low-speed, high-torque mode without requiring manual operator intervention, using existing hardware and software.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the vehicle operates in high-speed low-torque mode, then the vehicle achieves higher speeds, but the braking distance exceeds ISO 3450 standards

Engineering Contradiction:

Improvevehicle speedVSAvoidbraking distance compliance

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The system dynamically switches between high-speed low-torque mode and low-speed high-torque mode based on braking conditions. When braking is detected, the control system automatically transitions the propulsion system to low-speed high-torque mode to provide enhanced braking force, thereby achieving ISO 3450 compliance while maintaining high-speed capability during normal operation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the operating parameters of the hydrostatic transmission system by switching between two distinct modes: high-speed low-torque mode for normal operation and low-speed high-torque mode for braking. This parameter change allows the vehicle to meet braking distance requirements without compromising speed performance during non-braking conditions.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If manual mode switching is required for braking, then the operator can control the mode change, but the braking response time increases

Engineering Contradiction:

Improveoperator controlVSAvoidbraking response time

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The system performs self-service by automatically detecting braking conditions and switching to low-speed high-torque mode without requiring operator intervention. The control system monitors vehicle operations and autonomously transitions modes when braking is detected, eliminating the time delay associated with manual mode switching while maintaining operator control during normal operation.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention implements feedback control by continuously monitoring vehicle operation status and automatically responding to braking conditions. The control system receives feedback from vehicle sensors and automatically adjusts the propulsion mode accordingly, ensuring rapid response to braking events while maintaining ease of operation through automated decision-making.

Inventive Principle:

Principle #23Feedback

3Reliability

If additional brake system hardware is added to meet standards, then braking performance improves, but device complexity and cost increase

Engineering Contradiction:

Improvebraking distance complianceVSAvoidbrake system hardware

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention replaces the need for additional mechanical brake system hardware with a control-based solution. Instead of adding more physical brake components, the system uses the existing hydrostatic transmission system and control electronics to achieve enhanced braking performance by switching to low-speed high-torque mode, thereby reducing device complexity while meeting ISO 3450 standards.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention makes the existing propulsion system multi-functional by enabling it to provide both propulsion and enhanced braking functions. The hydrostatic transmission system, originally designed only for propulsion, is made universal by allowing it to contribute to braking through mode switching, eliminating the need for separate dedicated brake hardware and reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enhances braking efficiency, ensuring compliance with ISO 3450 standards by allowing quicker and more responsive braking without adding new hardware, applicable to vehicles with hydrostatic transmission systems.

Implementation Method 1

utilizing an electronic control unit and solenoid to enhance braking efficiency

Methodology Applied

Scientific EffectSolenoid: Solenoid

Data Source

PatentEP4286228B1High torque braking system

Publication Date: 2026.04.15 VOLVO CONSTRUCTION EQUIPMENT AB

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AI summary

A method of automatically activating a high-torque braking system in a heavy-duty vehicle configured to operate in at least one low speed, high torque mode and at least one higher speed, lower torque mode is disclosed. The method comprising determining a speed-controller of the vehicle is in a first position which results in the vehicle travelling in a higher-speed, lower-torque mode, and, responsive to detecting braking and a change in position of the speed-controller from the first position to a second, neutral, position, activating a low-speed high torque mode of operation for braking the vehicle.