Detecting operational state of a dishwasher
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Solution Overview
Problem
Existing dishwashers require bulky and expensive sensors to detect operational states such as extra wash zone activation and overfill situations, which is inefficient and costly.
Innovation Solution
A method and device that operate the dishwasher circulation pump at a rotational speed different from the nominal speed to measure the motor's operating current, allowing for the detection of extra wash zone activation and overfill situations without additional sensors, by analyzing changes in motor load and current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional sensors are used to detect operational states (extra wash zone activation, overfill situations), then detection reliability is improved, but device complexity and cost increase
Solution Approach 1:
The circulation pump motor is made to serve multiple functions: its primary function of circulating water is enhanced with a secondary detection function. By operating the motor at a reduced speed during a detection phase and measuring the resulting current consumption, the system can detect operational states (extra wash zone activation, overfill situations) without requiring separate sensors. This multi-functionality eliminates the need for additional detection devices.
Solution Approach 2:
The system uses its own existing components (circulation pump motor and current measurement capability) to perform detection functions that would otherwise require separate sensors. The motor's current consumption characteristics serve as the detection signal, allowing the system to self-diagnose operational states using resources already present in the dishwasher.
2Measurement precision
If additional sensors are used to detect operational states, then measurement precision is improved, but cost increases
Solution Approach 1:
The invention replaces expensive, bulky sensors with a low-cost detection method based on electrical current measurement. The detection phase uses temporary reduced-speed motor operation and standard current sensing already present in the motor control circuitry, eliminating the need for costly specialized sensors while maintaining adequate detection precision.
Solution Approach 2:
The invention replaces mechanical/sensor-based detection systems with an electrical measurement approach. Instead of using physical sensors to detect operational states, the system uses electrical current consumption characteristics of the motor as a proxy signal, substituting a complex mechanical sensing system with a simpler electrical measurement system.
3Productivity
If the circulation pump operates at nominal rotational speed, then washing productivity is maintained, but detection sensitivity decreases
Solution Approach 1:
The system performs a preliminary detection phase before the main washing cycle begins. During this preliminary phase, the circulation pump operates at a reduced speed to enable sensitive current-based detection of operational states. Once detection is complete and the pump returns to nominal speed for productive washing, the system has already identified any issues, allowing for timely intervention or cycle adjustment.
Solution Approach 2:
The invention implements periodic detection phases interspersed with productive washing phases. The circulation pump alternates between detection mode (reduced speed, high sensitivity) and washing mode (nominal speed, high productivity). This periodic switching allows the system to maintain both detection sensitivity and washing productivity without compromising either function permanently.
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 the detection of various operational states with increased sensitivity and accuracy, reducing the need for expensive sensors and allowing for automatic adjustment of washing cycles, while also identifying potential faults like faulty inlet valves or inferior water filling control.
Implementation Method 1
measure operating current of the motor driving the dishwasher circulation pump; determine whether the extra wash zone has been activated based on an increase in the measured circulation pump motor operating current
Data Source
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AI summary
The present invention relates to a method of, and a device (40) for, detecting an operational state of a dishwasher (10), in particular activation of extra wash zones and overfill situations. The device (40) is arranged to operate a motor (22) driving a dishwasher circulation pump (21) at at least one rotational speed differing from a nominal rotational speed and measure operating current of the motor (22) driving the dishwasher circulation pump (21). Further, the device is arranged to determine whether the dishwasher (10) operates in an operational state differing from a nominal operational state based on the measured circulation pump motor operating current.