Controlling method of a dishwasher

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Solution Overview

Problem

High spray pressure in dishwashers can damage dishes, increase water usage, and elevate power consumption, particularly due to excessive steam generation.

Innovation Solution

A method for controlling a dishwasher that includes a preliminary washing step with unheated water, alternating water supply through multiple spray arms, and alternating steam and water in subsequent main washing steps, with the sump heater turned off during steam use to reduce power consumption and enhance washing performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the spray pressure of washing water is increased to improve washing performance, then washing performance is improved, but dishes are liable to be damaged and broken

Engineering Contradiction:
Improvewashing performanceVSAvoiddish damage
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The washing process is divided into multiple sequential steps (pre-washing, first main washing, second main washing, rinsing) with different spray pressure levels. The pre-washing and rinsing steps use lower pressure to avoid damage, while the main washing steps use higher pressure for effective cleaning, thus segmenting the pressure application throughout the cycle.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The spray pressure is dynamically adjusted at different stages of the washing cycle rather than maintaining a constant high pressure. The system transitions between low-pressure and high-pressure phases according to the specific washing requirements of each step, optimizing both effectiveness and safety.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If the spray pressure of washing water is increased to improve washing performance, then washing performance is improved, but the amount of washing water used increases

Engineering Contradiction:
Improvewashing performanceVSAvoidwashing water amount
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The washing cycle is segmented into steps with different water consumption characteristics. The pre-washing step uses a smaller amount of water at low pressure to remove loose debris, reducing the need for large volumes of high-pressure water in subsequent steps.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The washing process employs periodic alternation between water spraying and steam generation phases. During steam phases, water heating occurs without direct high-pressure spraying, reducing overall water consumption while maintaining washing effectiveness through thermal action.

Inventive Principle:
Principle #19Periodic action

3Manufacturing precision

If the spray pressure of washing water is increased to improve washing performance, then washing performance is improved, but power consumption increases

Engineering Contradiction:
Improvewashing performanceVSAvoidpower consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The power-intensive high-pressure spraying is segmented into specific main washing steps rather than being applied continuously. The pre-washing and rinsing steps use lower power consumption, while steam generation phases provide thermal washing without requiring high-pressure pump operation, thus segmenting energy usage throughout the cycle.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system periodically alternates between mechanical high-pressure water spraying and thermal steam generation. During steam phases, the high-pressure pump is deactivated and heating elements operate instead, creating a periodic pattern that reduces cumulative power consumption while maintaining washing performance.

Inventive Principle:
Principle #19Periodic action

4Manufacturing precision

If steam is generated excessively to improve washing performance, then washing performance is improved, but power consumption increases

Engineering Contradiction:
Improvewashing performanceVSAvoidpower consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

Steam generation is implemented periodically rather than continuously. The washing cycle includes alternating phases of water spraying and steam generation, with steam produced in controlled intervals during the main washing steps. This periodic steam generation achieves effective washing while significantly reducing cumulative power consumption compared to continuous steam production.

Inventive Principle:
Principle #19Periodic 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

This method effectively washes dishes with reduced steam usage and power consumption, improving washing performance while minimizing dish damage and energy expenditure.

Implementation Method 1

The steam heater, which generates steam

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

the sump heater is maintained in a turned-off state during the second main washing step

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP2166914B1Controlling method of a dishwasher
Publication Date: 2018.01.24 LG ELECTRONICS INC
  • EP2166914B1 patent drawingFigure 1
  • EP2166914B1 patent drawingFigure 2~3

AI summary

A method for controlling a dishwasher sequentially performing a first main washing step, a second main washing step, and a third main washing step. The first main washing step includes supplying washing water, which is heated by a sump heater (290), to a washing chamber (150). The second main washing step includes selectively performing a steam spraying action for supplying steam to the washing chamber (150), and performing a water supplying action for supplying washing water to the washing chamber (150). The third main washing step includes supplying washing water, heated by the sump heater (290), to the washing chamber (150).