Vehicle Retarder Torque Control for Mass-Independent Deceleration

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Solution Overview

Problem

Conventional endurance braking systems for vehicles, particularly commercial vehicles, fail to account for vehicle-specific properties like mass and configuration, leading to variable deceleration results for the same torque requirements, and rely on numerous sensor values that increase susceptibility to errors.

Innovation Solution

A continuous braking device with an input device for selecting vehicle deceleration requests and a retarder control system that determines and adjusts retarder brake torque to achieve consistent deceleration independently of vehicle mass, using deceleration control principles to regulate permanent braking, thereby eliminating the need for complex sensor data and ensuring consistent braking performance across different loading conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional torque-based control is used, then the braking system is simple to operate, but the deceleration varies with vehicle mass and configuration

Engineering Contradiction:
Improvebraking control simplicityVSAvoiddeceleration consistency
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The control device continuously monitors actual vehicle deceleration and compares it with the requested deceleration, then adjusts the retarder brake torque in real-time to eliminate deviations. This closed-loop feedback ensures consistent deceleration performance regardless of vehicle mass or configuration changes.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adapts the brake torque based on current vehicle conditions by continuously adjusting the retarder control in response to changing vehicle mass, loading conditions, or road gradient, maintaining reliable deceleration control throughout operation.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If multiple sensor values are used for deceleration control, then the braking precision is improved, but the system complexity and error susceptibility increase

Engineering Contradiction:
Improvedeceleration control precisionVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention extracts and relies exclusively on the deceleration signal from the service brake system, eliminating the need for multiple sensors (vehicle mass, road gradient, engine torque). This single-signal approach maintains control precision while significantly reducing system complexity and error susceptibility.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The service brake deceleration signal acts as an intermediary that indirectly provides information about vehicle conditions and loading, allowing the control system to infer necessary parameters without directly measuring them with multiple sensors.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If torque-based braking control is used, then the system is simple to implement, but readjustments are frequently needed when vehicle configuration changes

Engineering Contradiction:
Improvesystem implementation simplicityVSAvoidloading condition adaptability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The continuous monitoring and adjustment of actual deceleration versus requested deceleration automatically compensates for changes in vehicle configuration or loading, eliminating the need for manual readjustments while maintaining simple system implementation.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3260336B1Vehicle retarder
Publication Date: 2021.08.25 MAN TRUCK & BUS SE
  • EP3260336B1 patent drawingFigure 1
  • EP3260336B1 patent drawingFigure 2
  • EP3260336B1 patent drawingFigure 3

AI summary

The invention relates to a continuous braking device for a vehicle. The continuous braking device comprises at least one continuous brake (4); an input device (2) by means of which a vehicle deceleration request (3) can be selected, which encodes a deceleration to be achieved starting from an existing deceleration of the vehicle; and a continuous brake control device (4) which is configured such that, depending on the selected vehicle deceleration request, it determines a continuous brake braking request (5) which encodes a continuous brake braking torque to be applied by the continuous brake (6), which, when the continuous brake braking torque is set by the at least one continuous brake, always causes the same deceleration of the vehicle for the same vehicle deceleration requests and, in particular, regardless of the current total vehicle mass.