Warning device for filter-changing time

Details Warning device for filter-changing time Warning device for filter-changing time

2000-04-21

2001-05-29

Tong, Nina (Department: 2632)

Communications: electrical

Land vehicle alarms or indicators

Internal alarm or indicator responsive to a condition of the...

C340S457400

Reexamination Certificate

active

06239694

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATION
This application is related to and claims priority from Japanese Patent Application No. Hei. 11-136024 filed on May 17, 1999, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a warning device for warning a filter-changing time, which is suitably used for a vehicle air conditioner, for example.
2. Description of Related Art
Because dust and smelling components are physically collected into a filter for an air conditioner, the filter is clogged with using time and using condition, and an air amount passing through the filter is decreased. For preventing a decrease of air-conditioning capacity due to the clogging of the filter, for example, in a conventional vehicle air conditioner described in JP-A-7-81392, an air amount passing through a filter is estimated based on a rotation speed of a blower fan and a vehicle speed, and a filter-changing time is determined so that a warning signal is output.
However, generally, the air amount passing through the filter is changed in accordance with a clogging degree of the filter. Therefore, it is difficult to accurately determine the air amount passing through the filter by the estimate due to the rotation speed of the blower fan and the vehicle speed. Further, the clogging degree of the filter is greatly relative to the using condition of the filter. Here, a sensor for detecting a signal directly relating to the air amount passing through the filter or a sensor for detecting a contaminated degree of air sucked into the filter may be provided so that the filter-changing time is accurately determined. However, in this case, production cost is increased with the sensor arrangement.
SUMMARY OF THE INVENTION
In view of the foregoing problems, it is an object of the present invention to provide a warning device for warning a filter-changing time for an air conditioner, which accurately performs a warning of the filter-changing time without using a sensor relating to a filter clogging, while being produced in low cost.
According to the present invention, a warning device includes a warning indication unit which indicates a warning of a filter-changing time, and a control unit for controlling operation of the warning indication unit. The control unit includes timer means which adds filter-using time for which air passes through the filter, setting means for setting an initial setting value of the timer means, resetting means for outputting a resetting signal for resetting the timer means when the filter is changed, and varying means for varying the initial setting value of the timer means to a next timer setting value after a change of the filter based on the filter-using time until a change of the filter. The control unit operates the warning indication unit, when the filter-using time passes the next setting value after the change of the filter. Thus, the filter-using time until a change of the filter is always used as the next timer setting value after the change of the filter. Therefore, the initial timer setting value is varied to the next timer setting value reflecting variation conditions of a clogging degree of the filter. As a result, a warning of the filter-changing time is performed at a suitable moment corresponding to actual using conditions of the filter, without using a sensor relating to the clogging degree of the filter.


REFERENCES:
patent: 4630027 (1986-12-01), Muhlberger et al.
patent: 5705977 (1998-01-01), Jones
patent: 5900811 (1999-05-01), Shaw et al.
patent: 5917408 (1999-06-01), Cardillo et al.
patent: 6141629 (2000-10-01), Yamamoto et al.
patent: 7-81392 (1995-03-01), None

Affiliated with

Also associated with

Rating

Warning device for filter-changing time does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Warning device for filter-changing time, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Warning device for filter-changing time will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2532829