Multi-Screw Coolant Pump for Low-Wear Engine Cooling

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Solution Overview

Problem

Existing centrifugal pumps for engine cooling circuits in vehicles are inefficient due to their performance dependence on rotation speed and operating conditions, leading to high mechanical consumption and CO2 emissions, and are not compact enough for automotive applications.

Innovation Solution

A multi-screw, rotary, positive displacement pump with hollow rotors and non-flanged bushings, featuring a unique design that minimizes friction and wear, allows axial floating of components, and includes a dynamic seal to maintain performance independence from rotation speed and operating conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If centrifugal pumps are used for engine cooling circuits, then the pumps can be mechanically connected to the engine rotation shaft, but the performance is strongly influenced by rotation speed leading to high mechanical consumption and fuel consumption

Engineering Contradiction:
Improvemechanical consumptionVSAvoidpump performance
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent replaces the traditional centrifugal pump mechanism with a multi-screw positive displacement pump mechanism. This substitution fundamentally changes how fluid is moved - from dynamic centrifugal force to positive displacement through screw threads - enabling performance independence from rotation speed and significantly reducing mechanical consumption and CO2 emissions

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

Solution Approach 2:

The patent changes the fundamental operating parameter relationship by using positive displacement technology where flow rate becomes independent of rotation speed. The multi-screw design with hollow rotors creates sealed chambers that physically displace fluid, decoupling performance from speed variations and maintaining consistent efficiency across different operating conditions

Inventive Principle:
Principle #35Parameter changes

2Stress or pressure

If the length of the screw is increased to increase maximum pressure output, then the pressure increases, but the product becomes not compact for automotive applications

Engineering Contradiction:
Improvemaximum pressureVSAvoidpump size
Core Design Contradiction:
Stress or pressureVSVolume of moving object

Solution Approach 1:

The patent divides the pumping function across multiple screws (typically three) working in parallel within a compact housing. Each screw handles a portion of the flow and pressure generation, allowing the system to achieve high pressure output without requiring any single screw to be excessively long, thus maintaining compact dimensions suitable for automotive installation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent optimizes the spatial arrangement of multiple screws in a three-dimensional configuration within the housing. By utilizing vertical and radial spacing efficiently, the design achieves high pressure capability through multi-screw collaboration rather than relying on extended screw length in a single dimension, resulting in a compact overall footprint

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Stability of the object's composition

If driven screws are radially guided by bushings, then the radial oscillation is limited, but friction and wear phenomena occur that could degrade performance over time

Engineering Contradiction:
Improveradial oscillationVSAvoidperformance degradation
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent introduces hydraulic bearings that use the pumped fluid itself to create a hydrodynamic film between the driven screws and the bearing surfaces. This fluid film replaces traditional solid bushings, eliminating direct metal-to-metal contact and the associated friction and wear, while still providing effective radial guidance and oscillation control

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The system uses the coolant fluid being pumped to lubricate and support the driven screws through hydraulic bearings. The fluid serves dual purposes: as the working medium for cooling and as the lubricant for reducing friction and wear on moving parts, eliminating the need for separate lubrication systems and improving long-term reliability

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

The pump achieves superior performance and reduced mechanical energy absorption, minimizing wear and friction while ensuring compactness and reliability, thus reducing CO2 emissions and improving fuel efficiency.

Implementation Method 1

A multi-screw, rotary, positive displacement motorpump for engine and auxiliary cooling circuits

Methodology Applied
Scientific EffectPositive displacement:

Data Source

PatentEP3967882B1Multiscrew pump for cooling circuits
Publication Date: 2025.11.12 METELLI
  • EP3967882B1 patent drawingFigure 1~4
  • EP3967882B1 patent drawingFigure 2~3

AI summary

A multi-screw pump (10) (14, 14') for cooling circuits, especially suitable for engine and auxiliary cooling circuits installed on vehicles with internal combustion engines, comprises a pump body (12) housing a plurality of rotors having a typically helical thread, and wherein the screw (14) or drive screw of a rotor is actuated by an electric or other motor (18), housed in a cover container body (18') so that the rotational motion is transferred to the other screws or driven screws (14'); said pump is provided with a dynamic seal, preferably a front mechanical seal (20) with sliding rings, and with possible static seals (24) for containing the processed fluid.