Electronic odometer

• US 4,803,646 A
• Filed: 08/26/1987
• Issued: 02/07/1989
• Est. Priority Date: 10/01/1984
• Status: Expired due to Term

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Ford Motor Company
• Inventors: Burke, Michael J., Lehner, Gerald J., Pidsosny, Richard A.
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): Cosimano, Edward R.
• Application Number:
  US07/089,466
• Time in Patent Office: 531 Days
• Field of Search: 73/490, 73/491, 235/95 R, 324/171, 324/172, 364/561, 377/24.1
• US Class Current: 702/165
• CPC Class Codes: G01C 22/02 by conversion into electric waveforms and subsequent integration, e.g. using tachometer generator G01C22/002, G01C22/004, G01C22/006 take precedence

Abstract

A system for measuring distance traveled by a vehicle periodically updates the accumulated measurements, displays the updated measurements and electronically stores corresponding accumulations of updated distance data in a non-volatile memory device. The system employs a method of reading through the sequentially ordered storage locations of the non-volatile memory to determine the most recently stored correct data value as a value to be both displayed and used as a base value for subsequent measured distance accumulation.

Claims

1. An electronic odometer for an automotive vehicle comprising:

sensor means on said vehicle for detecting movement of said vehicle and providing an output signal indicative of predetermined portions of distance traveled;

computer means connected to said sensor means for accumulating said output signals from said sensor means into predetermined increments of distance and outputting an odometer data value as the summation of all increments of distance said vehicle has traveled;

memory means, connected to said computer means, having a plurality of non-volatile and individually addressable locations each one having the capacity for storing an odometer data value corresponding to a summation of all predetermined increments of distance traveled by said vehicle along with predetermined parity codes; and

means connected to said computer means for displaying the odometer data value for visual observation within said vehicle,

said computer means programmed to read the most recently written parity correct odometer data value stored in one of the separately addressable locations of said non-volatile memory means as a base value, to accumulate data values from said sensor means output signal until each time an accumulated data value equals a predetermined increment of distance value to accumulate the occurrences of said accumulated data values equaling said predetermined increment of distance value, to sum the value of said accumulated increment occurrences and the base value read from said non-volatile memory means as the newest odometer data value, to write said newest odometer data value and a predetermined parity code to one of the individually addressable locations of said non-volatile memory means having an address that is different from that of the location containing the most recently stored odometer data value, whenever said newest odometer data value exceeds said base value by a predetermined amount that is greater than said predetermined increment, and whenever said newest odometer data value exceeds the most recently written odometer data value by said predetermined amount.

2. An electronic odometer as in claim 1 wherein said vehicle includes an ignition switch that is turned on during the operation of said vehicle and said computer means is also programmed to write said newest odometer data value and a predetermined parity code to one of the individually addressable locations of said non-volatile memory means having an address that is different from that of the location containing the most recently stored odometer data value, when said ignition switch is turned off.

3. An electronic odometer as in claim 1, wherein said addressable storage locations in non-volatile memory means are arranged in a repeatable ordered sequence so that when the last location in a sequence is addressed, the next location is the first location in that sequence.

4. An electronic odometer as in claim 3, wherein said computer means also performs said summing function whenever the vehicle is turned off.

5. An electronic odometer as in claim 4, wherein said computer means performs said read function and provides an error signal to said display means, in the event it cannot determine the most recently stored parity correct odometer data value stored in said non-volatile memory means, to indicate malfunction in said odometer.

6. An electronic odometer as in claim 5, wherein said computer means performs said read function by addressing each storage location in said non-volatile memory means and comparing each read data value having correct parity with previously read data values to determine the highest value, within a predetermined maximum difference, as the most recently stored odometer data value for said base value.