Electronic control system and method having monitor program monitoring function
AssigneeDenso Corporation
InventorSanae Hirata
Life of this patent
Estimating the term…
Abstract
An ECU is equipped with an engine control microcomputer for executing engine control and a throttle control microcomputer for executing throttle control. The engine control microcomputer is programmed to execute a monitor program. A time in the engine control microcomputer is set with a predetermined time each time the monitor program is executed normally. The timer switches automatically its output logic level at a port from high to low, when the time count reaches zero. When the output logic level is switched to low, a throttle motor is disabled.
Claims8
An electronic control system comprising:
- first and second microcomputer programmed to control a first object and a second object, respectively;
- the first microcomputer having a monitor program for checking a malfunction of the second microcomputer at a predetermined interval;
- the first microcomputer including timer means and timer setting means;
- the timer means counting time and switching an output logic level of a port when a time count reaches a predetermined value;
- and
- the timer setting means setting a new time count in place of the time counted by the timer means when the second microcomputer is operating normally and the monitor program is executed normally,
- wherein the timer setting means monitors an interval of executing the monitor program and sets the new time count when that interval is within a predetermined time range having a beginning time point and an end time point.
An electronic control method for a system having a first microcomputer and a second microcomputer, the first microcomputer including a monitor program and a timer, the electronic control method comprising:
- monitoring, by the first microcomputer, an operation of the second microcomputer based on the monitor program at successive predetermined intervals;
- counting, by the timer of the first microcomputer, time from a predetermined value which is set larger than the predetermined interval;
- checking, by the first microcomputer, whether the time counted by the counting step is within a predetermined time range, the predetermined time range having a beginning time point and an end time point, defined by the predetermined value and the predetermined interval;
- and
- determining, by the first microcomputer, abnormality of monitor program execution when the time counted is outside the predetermined range time range having the beginning time point and an end time point.
Dependencies are inferred from the claim text.