Electric Motor Pump Pre-heating via Joule Heating

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Solution Overview

Problem

Internal combustion engine water feeding systems face damage from freezing temperatures, as water in the pump and injector can freeze when the engine is started after prolonged parking in cold conditions, leading to potential damage from ice formation.

Innovation Solution

A method to control an electric motor operating a pump that includes a pre-heating procedure using Joule effect heat generated by the motor's windings to prevent ice formation and ensure the pump's integrity, without causing the pump's rotation, by supplying alternating electric currents in phase to create a stationary magnetic field and generate thermal power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pump is emptied of residual water to prevent freezing damage, then damage from ice formation is avoided, but the pump remains vulnerable to ice blocks when restarted after prolonged parking in sub-zero conditions

Engineering Contradiction:
Improvepump protection from freezing damageVSAvoidice block formation in pump
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The control method performs a preliminary heating action by supplying alternating electric currents in phase to the motor windings before the pump operates, creating a stationary magnetic field that generates Joule heat to warm the pump walls and prevent water freezing. This preliminary thermal preparation eliminates ice block formation when the pump restarts after prolonged parking in sub-zero conditions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention replaces the traditional mechanical heating system with an electrical heating solution. By utilizing the motor windings as heating elements through controlled alternating current supply, the system generates heat via Joule effect without requiring separate mechanical heating components, thereby preventing water freezing in the pump.

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

2Reliability

If a heating device is added to prevent water freezing, then pump damage from ice is avoided, but device complexity and cost increase

Engineering Contradiction:
Improvepump protection from freezing damageVSAvoidheating system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control method makes the motor windings multi-functional by enabling them to serve both as electromagnetic components for motor operation and as heating elements for thermal protection. By controlling the phase relationship of alternating currents supplied to the windings, the system can generate stationary magnetic fields for heating without requiring separate heating devices, thus avoiding increased device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its own motor windings to generate the heat needed for protection, making the heating function self-contained within the existing motor structure. The control unit manages the current supply to create Joule heating in the windings, allowing the motor itself to serve its own heating needs without external heating components.

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

Prevents damage to the pump by ensuring the walls are pre-heated before water flow resumes, avoiding ice formation and ensuring smooth operation even in sub-zero conditions without requiring hardware changes, making it economically viable and easy to implement.

Implementation Method 1

A method to control an electric motor operating a pump to feed a water-based operating liquid, in particular to pre-heat the walls of the pump and prevent the formation of ice blocks inside the pump, exploiting the Joule effect

Methodology Applied
Scientific EffectJoule effect: Joule Heating

Data Source

PatentEP3875746B1Method to control an electric motor, which operates a pump to feed a water-based operating liquid
Publication Date: 2022.04.06 MARELLI EURO SPA
  • EP3875746B1 patent drawingFigure 1
  • EP3875746B1 patent drawingFigure 2
  • EP3875746B1 patent drawingFigure 3

AI summary

A method to control an electric motor (25), which operates a pump (16) to feed a water-based operating liquid. The control method comprises the steps of: supplying, during a normal operation to pump the water-based operating liquid, three stator windings (27) of the electric motor (25) with three corresponding alternating electric currents (I1, I2, I3), which are out of phase by 120°, so as to generate a rotary magnetic field; and supplying, during a pre-heating procedure to pre-heat the pump (16) before starting to pump the water-based operating liquid, two sole stator windings (27) with two corresponding alternating electric currents (I1,I2), which are in phase with one another and, adding to one another, return through a third stator winding (27), so as to not determine any movement of a rotor (29) of the electric motor (25) and only generate heat due to Joule effect in the stator windings (27).