Data storage apparatus

• US 20020188427A1
• Filed: 05/20/2002
• Published: 12/12/2002
• Est. Priority Date: 06/08/2001
• Status: Active Grant

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Nishina, Masatoshi, Machino, Hideki
• Granted Patent: US 6,885,979 B2
• Time in Patent Office: Days
• US Class Current: 702/187
• CPC Class Codes: G01D 9/005 Solid-state data loggers

Abstract

There is provided a data storage apparatus which is capable of storing data efficiently over a long term without increasing the storage capacity thereof. An ECU samples data in a predetermined cycle. A plurality of items of the data sampled by the ECU are stored in a RAM. The items of the data stored in the storage means are updated to respective ones of the items of the data which were sampled at later times than times the plurality of items of the data were stored, in respective predetermined updating cycles which are longer as the plurality of items of the data were sampled at respective earlier times.

Claims

1. A data storage apparatus comprising:

sampling means for sampling data in a predetermined cycle;

storage means for storing a plurality of items of the data sampled by said sampling means; and

updating means for updating the plurality of items of the data stored in said storage means to respective ones of the plurality of items of the data which were sampled at later times than times the plurality of items of the data were stored, in respective predetermined updating cycles which are longer as the plurality of items of the data were sampled at respective earlier times.

2. A data storage apparatus according to claim 1, further comprising inhibiting means for inhibiting said updating means from updating the plurality of items of the data when a predetermined update inhibiting condition is satisfied.

3. A data storage apparatus according to claim 1, wherein the predetermined updating cycles are set to respective values each obtained by multiplying a predetermined value by 2ⁿ, where n is an integer equal to or larger than zero.

4. A data storage apparatus according to claim 2, wherein the predetermined updating cycles are set to respective values each obtained by multiplying a predetermined value by 2ⁿ, where n is an integer equal to or larger than zero.

5. A data storage apparatus according to claim 1, wherein said storage means comprises a plurality of storage areas associated with the predetermined updating cycles, respectively, and wherein said updating means updates the plurality of items of the data stored in respective ones of the plurality of storage areas, to ones of the plurality of items of the data updated in shorter ones of the predetermined updating cycles, in the predetermined updating cycles, respectively.

6. A data storage apparatus according to claim 1, wherein said storage means comprises a plurality of storage areas for storing latest ones of the plurality of items of the data which are updated in an updating cycle identical to the predetermined cycle in which the data is sampled.

7. A data storage apparatus according to claim 1, wherein said storage means comprises a plurality of storage areas for storing earliest ones of the plurality of items of the data which are updated in a longest one of the predetermined updating cycles.

8. A data storage apparatus according to claim 1, wherein the data comprises a plurality of kinds of data, and wherein said storage means stores a plurality of items of each of the plurality of kinds of data.