Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – With indicator or control of power plant
Reexamination Certificate
2001-06-06
2003-09-09
Vo, Hieu T. (Department: 3747)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
With indicator or control of power plant
C701S114000, C701S102000, C701S029000
Reexamination Certificate
active
06618666
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This application is based on and incorporates herein by reference Japanese Patent Application No. 2000-195867 filed Jun. 29, 2000.
BACKGROUND OF THE INVENTION
This invention relates to a vehicle electronic control unit and method, and particularly to a vehicle electronic control unit and method for measuring a soak time of an engine by using a timing part such as a clock IC (integrated circuit) which measures time continuously irrespective of whether a microcomputer is operating or stopped.
Electronic control units (ECUs) for vehicles use a built-in clock IC as a timing part or an external clock to measure elapsed time and use data from the clock IC to calculate a time period in which the ECU power supply has been turned off and a microcomputer held inoperative. This elapsed time is an engine stoppage time (soak time Ts).
In one proposal, the microcomputer reads in time measured by the clock IC at every predetermined interval (circle mark in
FIG. 5
) and stores this time data in a memory such as a standby RAM (SMAM) by updating. Thus, when an ignition (IG) switch is turned off, that is, the microcomputer is turned inoperative (time t
11
), the time data immediately before the turning off is held stored. When the IG switch is turned on again later (t
12
) to re-start the microcomputer operation, the microcomputer calculates the soak time Ts from the difference between the time data stored in the memory and the current time measured by the clock IC presently.
However, a power supply voltage of a battery falls temporarily when the engine is cranked by a starter. Thus, a main power supplied to the microcomputer falls below a predetermined voltage VMC required for the microcomputer to operate, and the microcomputer tends to be reset from time t
13
to time t
14
. As a result, when the microcomputer starts operating after being reset, the soak time Ts which has already been calculated immediately after the turning on of the IG switch is calculated again. This recalculated soak time Ts becomes very short. This problem is phenomenal in winter when the battery power is lowered due to low ambient temperature.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide an electronic control unit and method which can measure an engine soak time accurately.
According to the present invention, an electronic control unit for a vehicle has a timing part continuously supplied with an electric power to measure time, a control part operable to carry out a predetermined operation when the electric power is supplied, and a memory which stores the measured time. The memory continues to store the time data of the timing part measured immediately before an engine of the vehicle is stopped. The control part calculates a soak time of the engine from the stored time data and a current time data of the timing part when an engine cranking is completed. The completion of engine cranking may be detected from a rise of rotation speed of the engine to a predetermined speed.
REFERENCES:
patent: 5079727 (1992-01-01), Yasue et al.
patent: 5995886 (1999-11-01), Tanaka et al.
patent: 6169942 (2001-01-01), Miller et al.
patent: 4-292545 (1992-10-01), None
patent: 9-160602 (1997-06-01), None
Amano Isao
Sugimura Atsushi
Denso Corporation
Nixon & Vanderhye P.C.
Vo Hieu T.
LandOfFree
Electronic control unit and method for measuring engine soak... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electronic control unit and method for measuring engine soak..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electronic control unit and method for measuring engine soak... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3022672