Self-diagnostic apparatus of vehicles
First Claim
1. A self-diagnostic apparatus for a vehicle comprising:
- data detection means for detecting diagnostic data concerning an operation parameter of at least one device in said vehicle;
diagnostic data storage means for updating and storing said diagnostic data and for maintaining said stored diagnostic data even when an ignition switch of said vehicle is turned off;
updating period changing means for changing a time period of updating by said diagnostic data storage means, and for detecting a rate of change of said diagnostic data, said time period being changed to update data stored in said diagnostic data storage means at an updating time period which decreases as said detected rate of change increases;
abnormality detection means for detecting an abnormal operating state in accordance with said diagnostic data of said device; and
inhibition means for inhibiting said diagnostic data from being updated after said abnormal operating state is detected.
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Accused Products
Abstract
A self-diagnostic apparatus of vehicles which allows frozen diagnostic data to reflect correctly and efficiently a vehicle state upon the detection of an abnormality. A control unit has a CPU and a RAM which holds stored data even when the ignition key is turned off. The CPU detects an abnormality of individual on-board devices and when an abnormality of a device is detected, it stops updating diagnostic data and maintains data immediately prior to the detection of the abnormality. When updating of diagnosis data is not stopped, the contents of the RAM is updated at a predetermined updating period of time with diagnostic by data necessary for analyzing the device abnormality. The updating period becomes shorter as the rate of change of the diagnostic data grows larger. Through this, an adequate amount of diagnostic data near a time point at which the device abnormality occurs can be reliably and efficiently stored for later retrieval.
122 Citations
8 Claims
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1. A self-diagnostic apparatus for a vehicle comprising:
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data detection means for detecting diagnostic data concerning an operation parameter of at least one device in said vehicle; diagnostic data storage means for updating and storing said diagnostic data and for maintaining said stored diagnostic data even when an ignition switch of said vehicle is turned off; updating period changing means for changing a time period of updating by said diagnostic data storage means, and for detecting a rate of change of said diagnostic data, said time period being changed to update data stored in said diagnostic data storage means at an updating time period which decreases as said detected rate of change increases; abnormality detection means for detecting an abnormal operating state in accordance with said diagnostic data of said device; and inhibition means for inhibiting said diagnostic data from being updated after said abnormal operating state is detected. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification