Engine Cooling Thermostat Early Opening Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In heat engine cooling systems, the cold thermostat opens slowly due to a large temperature difference between the main circuit and the heat exchange circuit, leading to positive and negative temperature overshoots, which can activate the cooling fan unnecessarily, increasing consumption and potentially damaging the thermostat.

Innovation Solution

A method for early opening of the cold controlled thermostat, where a corrective command is applied based on a temperature difference threshold and specific engine or climatic conditions, ensuring the thermostat opens before reaching the setpoint temperature, thereby preventing overheating and reducing consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the thermostat is controlled based on stabilized regime parameters, then the setpoint temperature is maintained accurately under normal conditions, but the thermostat opens slowly when there is a large temperature difference between the main circuit and heat exchange circuit

Engineering Contradiction:
Improvethermostat opening speedVSAvoidtemperature regulation accuracy
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The control unit detects conditions indicating a large temperature difference (such as engine operating conditions or climatic conditions) and applies a corrective opening command to the thermostat before the temperature difference actually causes delayed opening. This preliminary action prevents the problem from occurring in the first place.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses indirect indicators (engine operating conditions, climatic conditions) to infer the temperature difference state rather than directly measuring it. This copying approach allows the control system to anticipate and correct for the temperature difference effect without requiring direct temperature sensors in both circuits.

Inventive Principle:
Principle #26Copying

2Stability of the object's composition

If the thermostat opens slowly due to temperature difference, then the regulation system maintains stability, but positive temperature overshoot occurs which triggers the cooling fan unnecessarily

Engineering Contradiction:
Improvetemperature stabilityVSAvoidcooling fan energy consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The corrective opening command counteracts the anticipated delayed opening effect before it can cause temperature overshoot. By opening the thermostat slightly earlier than the standard regulation would dictate, the system prevents the positive temperature rise that would otherwise trigger the cooling fan.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The control unit continuously monitors temperature and compares it with the setpoint, then adjusts the thermostat opening command accordingly. When a temperature difference condition is detected, the feedback loop applies a corrective command that anticipates and prevents the temperature overshoot problem.

Inventive Principle:
Principle #23Feedback

3Device complexity

If the thermostat opens slowly, then the mechanical system maintains its design characteristics, but negative temperature rise occurs which is detrimental to energy consumption

Engineering Contradiction:
Improvethermostat mechanical simplicityVSAvoidenergy consumption
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The control unit applies a corrective opening command in advance when conditions suggest a large temperature difference will occur. This preliminary action ensures the thermostat opens at the appropriate time, preventing negative temperature rise and the associated energy consumption penalties.

Inventive Principle:
Principle #10Preliminary action

4Measurement precision

If the regulation parameters are optimized for stabilized regime, then the setpoint is maintained under normal conditions, but the thermostat does not open early enough under transient conditions with large temperature differences

Engineering Contradiction:
Improvesetpoint temperature monitoring accuracyVSAvoidthermostat opening delay
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The control system dynamically adjusts the thermostat opening command based on detected conditions. When a large temperature difference condition is detected, the system applies a corrective command that modifies the opening timing, transitioning from the stabilized regime optimization to a transient condition response.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses indirect measurements (engine operating conditions, climatic conditions) to infer the temperature difference state and adjust timing accordingly, rather than requiring direct real-time temperature measurement in both circuits.

Inventive Principle:
Principle #26Copying

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

This approach prevents untimely activation of the cooling fan, reduces consumption, and protects the thermostat by ensuring gradual opening, thus maintaining optimal temperature regulation and extending its durability.

Implementation Method 1

The thermostat consists of a wax cartridge. The wax expands, opening the passage for the cooling fluid. The thermostat is controlled by heating the wax to shift the opening point to a lower temperature.

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

a main cooling circuit for the circulation of a cooling fluid... passing through the heat engine and removing heat from it

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 3

a main cooling circuit for the circulation of a cooling fluid

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 4

a heat exchange circuit for cooling the fluid, this heat exchange circuit including at least one or more radiators

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3870819B1Method for early opening of a cold thermostat in an engine cooling system
Publication Date: 2023.03.01 STELLANTIS AUTO SAS
  • EP3870819B1 patent drawingFigure 1
  • EP3870819B1 patent drawingFigure 2

AI summary

The invention concerns a method for early opening of a cold controlled thermostat in a system for fluid cooling of a heat engine, the thermostat operating a closure and an at least partial opening of a heat exchange circuit with respect to a main circuit of the system, the thermostat being controlled by a regulating command (Creg) for opening based on a current temperature (Tf) of the fluid and a setpoint temperature (Tcons). A corrective command (Ccor) for opening the thermostat is established when a variation between the current temperature (Tf) and the setpoint temperature (Tcons) is less than a first predetermined threshold (S1) and when at least one operating condition of the engine or at least one external climatic condition has been recognised by experience as involving a temperature difference (dT) between the respective fluids of the heat exchange and main circuits above a threshold of temperature variation between fluids.