Powertrain Slip Control for Hydraulic Fluid Thermal Regulation

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Solution Overview

Problem

Existing motor vehicle powertrain control systems face challenges in precision due to response dispersion in hydraulic actuation circuits at low temperatures, affecting piloting accuracy.

Innovation Solution

A method to regulate the temperature of the actuating fluid in the hydraulic distributor by determining a temperature threshold and controlling the slip state to bring the fluid temperature above this threshold, using a temperature sensor and adjusting the slip torque to minimize response dispersion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the hydraulic distributor operates at low temperature, then the system consumes less energy, but the response dispersion increases and piloting precision deteriorates

Engineering Contradiction:
Improveactuating fluid temperatureVSAvoidpiloting precision
Core Design Contradiction:
TemperatureVSMeasurement precision

Solution Approach 1:

The patent changes the temperature parameter of the actuating fluid from low to above-threshold levels by controlling the coupling device slip state. This parameter change resolves the contradiction by ensuring the hydraulic distributor operates at temperatures where response dispersion is minimized, thereby improving piloting precision without excessive energy consumption.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The control system continuously monitors the actuating fluid temperature and adjusts the slip state of the coupling device accordingly. When temperature drops below the threshold, the system increases slip to generate heat; when temperature is sufficient, it reduces slip. This feedback mechanism maintains optimal operating temperature and precision dynamically.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If the coupling device operates in slip state to heat the actuating fluid, then the piloting precision improves, but energy is dissipated as thermal energy

Engineering Contradiction:
Improvepiloting precisionVSAvoidenergy dissipation
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The patent converts the harmful effect of energy dissipation during slip into a beneficial thermal effect. By intentionally controlling the slip state, the system generates heat that raises the actuating fluid temperature to optimal levels, thereby improving hydraulic distributor performance. The energy loss is transformed into a useful heating function.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system applies slip state partially or excessively beyond what is strictly necessary for torque transmission, specifically to generate heat. The slip torque is controlled to be sufficient to raise the fluid temperature above the threshold but not excessive to cause unnecessary energy waste. This balanced approach achieves precision improvement with controlled energy consumption.

Inventive Principle:
Principle #16Partial or excessive action

3Temperature

If the transmissible torque is reduced below motor torque to control slip state, then the actuating fluid temperature increases, but the torque transmission capability decreases

Engineering Contradiction:
Improveactuating fluid temperatureVSAvoidtorque transmission
Core Design Contradiction:
TemperatureVSForce

Solution Approach 1:

The system employs periodic or intermittent slip control rather than continuous slip. The coupling device alternates between locked state (for full torque transmission) and slip state (for heating the fluid). This periodic action allows the system to achieve necessary temperature levels while maintaining torque transmission capability during locked periods, balancing both requirements.

Inventive Principle:
Principle #19Periodic action

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

Improves the precision of hydraulic distributor control and piloting by utilizing heat dissipation from the slipping state to heat the actuating fluid, reducing operational hysteresis and enhancing overall system accuracy.

Implementation Method 1

when a clutch operates in a slipping state, thermal energy is dissipated and transmitted to the lubricating oil

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

thermal energy is dissipated and transmitted to the lubricating oil

Methodology Applied
Scientific EffectViscous heating: Viscous Heating

Data Source

PatentEP3625472B1Method for controlling a power train for thermal regulation of a hydraulic circuit
Publication Date: 2021.01.20 PSA AUTOMOBILES SA
  • EP3625472B1 patent drawingFigure 1~2
  • EP3625472B1 patent drawingFigure 3~4
  • EP3625472B1 patent drawingFigure 5~6

AI summary

The invention relates to a method for controlling a power train of a motor vehicle for thermal regulation of a hydraulic actuator circuit. The method comprises a step of determining (52) a temperature of a fluid for actuating an actuator circuit and controlling a slipping state (53) of a coupling device so as to modify the temperature of the actuating fluid. According to the invention, the method also comprises determining a predetermined temperature threshold of the actuating fluid and, when the temperature of the actuating fluid is lower than a temperature threshold, controlling the slipping state (53) according to a slipping torque in order to bring the temperature of the actuating fluid above the temperature threshold.