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Publication Date: 2009-Oct-09
Document File: 3 page(s) / 55K

Publishing Venue

The Prior Art Database


The present invention discloses a method for optimizing dry cycle time of a washer/dryer. The method enables optimization of the dry cycle time by measuring the size of the load in real time. Further, the method advantageously reduces energy wastage and eliminates a damp load at the end of each dry cycle.

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The present invention relates generally to washing and drying appliances, and more particularly to a method for optimizing dry cycle time.

Washers and dryers are among the most commonly used consumer appliances. They are available as separate appliances and as a combination of washer/dryer. Each washer has a washing capacity referred to as a dry load. Typically, a washer uses a conductive sensor to determine an initial dry load. The dry load is equivalent to a weight of clothes placed in the washer for washing. Once a washing cycle is over, the clothes are transferred from the washer to the dryer. The washer communicates the initial dry load and amount of water absorbed by the clothes to the dryer.

Based on data communicated by the washer, the dryer estimates a wet load size and accordingly calculates a dry cycle time. For example, the dryer calculates a low dry cycle time if the data communicated by the washer indicates that the amount of water absorbed by the clothes is low (indicated by the nearly identical initial dry load and the dryer load). However, a user can occasionally modify the wet load by adding or removing some clothes from the dryer. In such instances, the estimation of the dry cycle time is not correct.

Further, conductive sensors employed in washers do not provide an accurate measurement of the initial dry load. However, the initial dry load is used to identify the amount of water absorbed by the clothes. Failure to measure the initial dry load accurately hampers the capability of the dryer to predict the dry cycle time. Furthermore, when a load is overly heavy, the washer is not able to achieve a final spin speed effectively. This leads to more than normal water remaining in the clothes after the wash cycle is over and therefore results in a longer dry cycle time.

Additionally, in some washer/dryer appliances, the dry cycle time is adjusted based on user inputs, such as load size and fabric type. The fabric type input takes into account different fabrics having different water retention capacities. Unfortunately, user inputs such as fabric type



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and load size are either not accurate or not sufficient for the dryer to adjust the dry cycle time optimally. In addition, various factors contribute to inaccurate calculation of the dry cycle time. Non-optimal dry cycle time leads to wastage of energy or damp clothes at the end of the dry cycle.

It would be desirable to have a method of optimizing the dry cycle time for a dryer.


Figure 1 is a schematic diagram of a method for optimizing the dry cycle time of a dryer in accordance with one embodiment of the present invention.


Figure 1 illustrates a schematic diag...