Electromagnetic Actuator Temperature Estimation Without Sensors

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Solution Overview

Problem

Existing methods for estimating the temperature of electromagnetic actuators in internal combustion engines are unreliable due to component tolerances and require costly dedicated sensors, leading to potential overheating issues.

Innovation Solution

A method that estimates the temperature of electromagnetic actuators by measuring the time it takes for the current through the coil to reach a threshold value, using a reference development plane to account for variations in component tolerances without the need for dedicated sensors, allowing for real-time temperature monitoring and protection measures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If dedicated temperature sensors are installed in electromagnetic actuators, then temperature detection accuracy is improved, but manufacturing cost and device complexity increase

Engineering Contradiction:
Improvetemperature detection accuracyVSAvoidsensor installation and maintenance
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses the electrical current as an intermediary parameter to indirectly measure temperature. Instead of directly measuring temperature with sensors, the system measures the current through the coil and uses the known relationship between current and temperature to determine the actuator temperature, eliminating the need for dedicated temperature sensors

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/physical temperature sensing system with an electrical measurement system. By substituting the dedicated temperature sensor with electrical current measurement and computational analysis, the system achieves temperature detection without additional hardware sensors

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

2Device complexity

If temperature estimation uses peak current time measurement, then device complexity is reduced, but measurement precision deteriorates due to component tolerances

Engineering Contradiction:
Improvemeasurement system simplicityVSAvoidtemperature estimation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary characterization of the electromagnetic actuator to establish the reference development curve before actual temperature measurement. This pre-established reference data is then used during operation to accurately determine temperature from current measurements, compensating for component variations

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback by comparing the actual current development against the reference development curve. The deviation between actual and reference measurements is used to calculate and compensate for temperature effects, improving measurement accuracy through iterative correction

Inventive Principle:
Principle #23Feedback

3Productivity

If electromagnetic actuators operate in high temperature environments, then productivity is improved, but reliability decreases due to overheating risks

Engineering Contradiction:
Improveoperational capacityVSAvoidoverheating prevention
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system continuously monitors the electrical characteristics of the electromagnetic actuator and provides feedback about its thermal state. This real-time feedback enables the control system to adjust operating parameters or trigger protective measures before overheating damages occur, maintaining reliability during high-productivity operation

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The electromagnetic actuator essentially monitors its own thermal state through its electrical characteristics. The coil's electrical behavior naturally reflects its temperature condition, allowing the system to self-diagnose thermal issues without external temperature sensors

Inventive Principle:
Principle #25Self-service

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 method provides a reliable and cost-effective way to estimate the temperature of electromagnetic actuators, reducing the risk of overheating and eliminating the need for dedicated sensors, while allowing for proactive protection measures to prevent damage.

Implementation Method 1

an electromagnetic actuator (5) comprising a coil (7)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the time needed by the current flowing through the coil to reach a peak current depends on the temperature of the coil

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4098859B1Method to estimate the temperature of an electromagnetic actuator
Publication Date: 2024.06.26 MARELLI EURO SPA
  • EP4098859B1 patent drawingFigure 1
  • EP4098859B1 patent drawingFigure 2
  • EP4098859B1 patent drawingFigure 3

AI summary

A method to estimate the temperature of an electromagnetic actuator (1), which entails a preliminary step in which to define a first threshold value (IT, IT*, IT1) for the current or for the voltage; and define a characteristic curve (C) of the actuator family in the plane temperature / time needed to reach the threshold value (IT, IT*, IT1); a step in which to carry out a reference measurement, in which, using the characteristic curve (C), a reference time (Sref) needed by the electromagnetic actuator (1) to reach the first threshold value (IT, IT*, IT1) is associated with a known reference temperature (Tref); and a step in which to carry out a series of measurements in which to determine the time needed by the electromagnetic actuator (1) to reach the first threshold value (IT, IT*, IT1), calculate the deviation (Δ) between the time needed by the electromagnetic actuator (1) to reach the first threshold value (IT, IT*, IT1) and the reference time (Sref); and determine the temperature of the electromagnetic actuator (1), using the characteristic curve (C), by associating the temperature of the electromagnetic actuator (1) with the sum (SΔ) of the deviation (Δ) and of the reference time (Sref).