Hydraulic Device Control Torque Safety Margin

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Solution Overview

Problem

Conventional systems for controlling engines powering hydraulic devices in heavy vehicles struggle to maintain high power while minimizing fuel consumption and preventing engine stalling, especially when the torque demand exceeds the maximum torque available.

Innovation Solution

A method that continuously monitors the current maximum torque and torque demand, incorporating a safety margin based on engine speed to adjust the control signal to the hydraulic device, ensuring the engine does not stall by scaling or stopping the control signals accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the engine speed is maintained at a preset speed to provide high power to the hydraulic device, then the power output is improved, but the fuel consumption increases and the risk of engine stalling increases

Engineering Contradiction:
Improvepower output to hydraulic deviceVSAvoidfuel consumption
Core Design Contradiction:
PowerVSUse of energy by moving object

Solution Approach 1:

The engine speed is no longer maintained at a fixed preset speed but is dynamically adjusted based on real-time torque demand and available torque calculations. The control system continuously monitors engine parameters and adjusts the engine speed profile to match actual operational needs, allowing the engine to operate at lower speeds when full power is not required, thereby reducing fuel consumption while maintaining adequate power delivery.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control system implements continuous feedback by monitoring engine speed, torque demand, and available torque parameters. The controller calculates the torque margin (difference between available and demanded torque) and uses this feedback to dynamically adjust engine control signals, creating a closed-loop control system that optimizes fuel consumption while preventing engine stalling conditions.

Inventive Principle:
Principle #23Feedback

2Use of energy by moving object

If the engine speed is reduced to lower fuel consumption, then the fuel efficiency is improved, but the power output decreases and the engine may stall

Engineering Contradiction:
Improvefuel consumptionVSAvoidpower output to hydraulic device
Core Design Contradiction:
Use of energy by moving objectVSPower

Solution Approach 1:

The system dynamically adjusts engine speed based on real-time conditions rather than operating at a fixed low speed for fuel efficiency. When torque demand increases, the engine speed is automatically increased to maintain adequate power output. This dynamic adaptation allows the engine to operate at fuel-efficient speeds during low-demand periods while ensuring sufficient power availability when needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control system continuously monitors torque demand and available torque parameters, using this feedback to adjust engine speed in real-time. When the torque margin becomes too small (indicating potential power deficiency), the system increases engine speed to maintain the required power output, preventing both stalling and excessive fuel consumption.

Inventive Principle:
Principle #23Feedback

3Power

If the torque demand is increased to meet hydraulic device requirements, then the power delivery is improved, but the risk of engine stalling increases when torque demand exceeds maximum available torque

Engineering Contradiction:
Improvetorque delivery to hydraulic deviceVSAvoidengine stalling risk
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The control system performs preliminary calculations of available torque and torque margin before the engine is actually overloaded. By continuously monitoring engine parameters and predicting the torque margin, the system takes preventive action by adjusting engine control signals before the torque demand exceeds available torque, thereby preventing engine stalling rather than reacting after it occurs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements continuous feedback monitoring of torque demand versus available torque parameters. When the torque margin approaches critical levels, the control system automatically adjusts engine operation to maintain adequate torque headroom, creating a safety buffer that prevents engine stalling while still allowing high torque delivery when conditions permit.

Inventive Principle:
Principle #23Feedback

4Device complexity

If a fixed engine speed control is used to simplify control system design, then the device complexity is reduced, but the ability to optimize fuel consumption and prevent stalling is compromised

Engineering Contradiction:
Improvecontrol system complexityVSAvoidengine stalling prevention
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent replaces complex mechanical governor systems or hydraulic speed control mechanisms with an electronic control system that calculates torque margins and adjusts engine parameters through software algorithms. This substitution reduces mechanical complexity while enabling more sophisticated control strategies that continuously optimize fuel consumption and prevent stalling through digital computation of torque parameters.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The control system dynamically changes engine operating parameters (such as fuel injection timing, air intake, and throttle position) based on calculated torque margin parameters. By modifying these parameters in real-time according to actual torque demands, the system achieves adaptive control that prevents stalling and optimizes fuel consumption without requiring overly complex control architecture.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2294319B1Hydraulic device control
Publication Date: 2018.05.09 SCANIA CV AB
  • EP2294319B1 patent drawingFigure 1
  • EP2294319B1 patent drawingFigure 2
  • EP2294319B1 patent drawingFigure 3

AI summary

In a method and a system for controlling a hydraulic device of a motorized vehicle the risk of stalling an engine used to power a motorized vehicle and the hydraulic device is eliminated or reduced by invoking a safety margin when controlling the hydraulic device. The current maximum torque that the engine can deliver is continuously monitored along with the current torque demand. The control signal to the hydraulic device is then controlled in response to the difference between the maximum torque and the torque demand. Hereby it is possible to invoke a suitable torque safety margin preventing the engine from stalling, which could be the result if the torque demand would exceed the maximum torque available.