Dishwasher Spraying Arm Channel Control Using Motor Current Feedback

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Solution Overview

Problem

Conventional dishwashers cannot determine which channels wash water is supplied to in the spraying arm, leading to inefficient washing and inability to actively control the rotational direction of the spraying arm, which affects washing efficiency.

Innovation Solution

A dishwasher with a spraying arm featuring first and second channels that can be selectively supplied with wash water based on current values measured by a motor, allowing the controller to differentiate between the two states and control the rotational direction accordingly, and a flow path conversion unit to alternate supply between channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If wash water is alternatively supplied to multiple channels in the spraying arm, then the spraying arm can rotate in different directions, but the system cannot determine which channel is currently supplied, leading to loss of information about the supply state

Engineering Contradiction:
Improverotational direction controlVSAvoidchannel supply state information
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The system measures the current value from the motor driving the supply pump and uses this feedback to determine which channel is currently supplied with wash water. The controller compares the measured current value with reference values to identify the active channel, thereby eliminating information loss about the supply state.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces mechanical indicators or sensors with an electrical measurement approach. By measuring the electrical current consumed by the motor under different channel supply conditions, the system can electronically determine the supply state without adding complex mechanical detection mechanisms.

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

2Productivity

If wash water is supplied to channels alternatively, then the spraying arm rotates periodically, but intensive washing of the dispenser at the initial stage cannot be achieved

Engineering Contradiction:
Improvewashing efficiencyVSAvoidcontrolled water supply timing
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The system dynamically adjusts the water supply strategy based on the washing stage. During the initial stage, the controller supplies wash water intensively to the channel directing water toward the dispenser. As the washing progresses, the system alternates between channels to maintain arm rotation and overall washing effectiveness.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs preliminary intensive washing of the dispenser by supplying wash water to the appropriate channel during the initial stage before transitioning to alternating supply模式. This ensures the dispenser receives focused attention when it最需要 cleaning.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If the spraying arm rotates periodically to cover all channels, then all areas can be washed, but the rotational direction cannot be actively controlled

Engineering Contradiction:
Improverotational direction controlVSAvoidwashing efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

By continuously monitoring the current value from the motor, the system gains feedback about which channel is active. This allows the controller to actively determine the rotational direction based on real-time supply state information, enabling adaptive control rather than passive periodic rotation.

Inventive Principle:
Principle #23Feedback

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

Enables intensive wash water supply to the dispenser at the initial stage of the wash cycle and active control of the spraying arm's rotational direction, enhancing washing efficiency and ensuring even water distribution to both front and rear portions of the rack.

Implementation Method 1

a supply pump comprising an impeller and a motor that drives the impeller and supplies the wash water stored in the sump to the spraying arm

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3311726B1Dishwasher and control method therefor
Publication Date: 2024.07.31 LG ELECTRONICS INC
  • EP3311726B1 patent drawingFigure 1
  • EP3311726B1 patent drawingFigure 2(a)~2(b)
  • EP3311726B1 patent drawingFigure 3(a)~3(b)

AI summary

The present invention relates to a dishwasher and a control method therefor, the dishwasher comprising: a tub for providing a washing space; a sump for collecting the washing water sprayed into the tub; a spraying arm having first and second channels, in each of which the washing water separately flows, and a plurality of spraying holes for discharging the washing water, which flows into each channel, in a preset direction; a supply pump including an impeller and a motor for rotating the impeller, and supplying the washing water, which is stored in the sump, to the spraying arm; a channel switching unit for selectively supplying the washing water to the first channel or the second channel according to the driving of the supply pump; and a control unit for controlling the driving of the motor, wherein a control unit controls the driving of the motor such that the washing water is selectively supplied to the first channel or the second channel, on the basis of a value of an electric current flowing into the motor.