Starter Motor Thermal Prediction for Overheat Prevention

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Solution Overview

Problem

Starter motors in motor vehicles, especially those with automatic stop and restart systems, are prone to overheating due to repeated and frequent activation, which can impact their operation and lifespan, and existing strategies for managing temperature are limited to inhibiting functions only when critical temperatures are reached.

Innovation Solution

A method and system that predict the remaining activation time before the starter overheats by using a thermal model and sensors to measure and estimate temperature values, allowing for proactive management strategies to prevent overheating, such as inhibiting automatic stop and restart functions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If the starter is activated frequently for automatic stop and restart operations, then the vehicle's automatic stop and restart function is improved, but the starter temperature increases and risks overheating

Engineering Contradiction:
Improveautomatic stop and restart functionVSAvoidstarter temperature
Core Design Contradiction:
Extent of automationVSTemperature

Solution Approach 1:

The system performs preliminary temperature prediction before starter activation using a thermal model that calculates predicted temperature based on activation duration and ambient conditions. This allows the control system to authorize or inhibit restart operations before the starter is activated, preventing overheating before it occurs rather than reacting after temperature thresholds are exceeded.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors actual starter temperature during operation and compares it with predicted temperature values. This feedback mechanism allows the control system to adjust authorization decisions in real-time, maintaining the automatic stop and restart function while preventing overheating by inhibiting operations when predicted temperatures would exceed safe thresholds.

Inventive Principle:
Principle #23Feedback

2Reliability

If the starter activation duration is extended to ensure complete engine starting, then the starting reliability is improved, but the temperature rise increases and may cause overheating

Engineering Contradiction:
Improvestarting reliabilityVSAvoidstarter temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The thermal model predicts temperature evolution during the entire planned activation duration before the starter is activated. This allows the system to determine the maximum safe activation duration that ensures complete engine starting while staying within temperature thresholds, optimizing both reliability and temperature management.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system adjusts the authorized activation duration parameter dynamically based on predicted temperature evolution. When predicted temperatures approach thresholds, the system reduces the authorized duration; when temperatures are low, it allows longer durations, thereby ensuring reliable starting while preventing overheating through adaptive parameter adjustment.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the temperature threshold for inhibiting stop and restart function is used, then the starter is protected from overheating, but the automatic stop and restart function is limited to only post-threshold inhibition

Engineering Contradiction:
Improvestarter protectionVSAvoidtemperature management strategy
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

Instead of waiting for temperature thresholds to be exceeded, the system calculates predicted temperature evolution during the planned activation and authorizes or inhibits operations in advance. This proactive approach expands temperature management from simple post-threshold inhibition to predictive control that optimizes the automatic stop and restart function across a wider range of operating conditions.

Inventive Principle:
Principle #10Preliminary 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

The system effectively predicts the time before overheating, enabling proactive management to prevent damage to the starter motor, thereby extending its lifespan and ensuring safe vehicle operation.

Implementation Method 1

measuring, at an instant, a first temperature value T1 by a sensor arranged at a point of the starter

Methodology Applied
Scientific EffectTemperature measurement:

Implementation Method 2

a predicted temperature evolution during the activation of the starter... determined... according to a thermal model

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

the thermal coefficient C is equal to P broom where P broom is the thermal power of the brushes

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3120012B1Method of controlling operation of a starter of a combustion engine in order to prevent a possible overheat during the start
Publication Date: 2018.05.02 PSA AUTOMOBILES SA
  • EP3120012B1 patent drawingFigure 1
  • EP3120012B1 patent drawingFigure 2
  • EP3120012B1 patent drawing

AI summary

A method for managing the operation of a starter configured to start a heat engine comprising: a step of determining a first temperature value; a step of determining thermal coefficients corresponding to the first temperature value of a pre-established thermal model describing the development over time of the temperature at said point of the starter; a step of calculating the time remaining for the temperature at a point of the starter to reach a second temperature value higher than the first temperature value, on the basis of the pre-established thermal model; and a step of inhibiting the starter, at least for a predefined period of time, when said remaining time is less than a predefined period of time.