Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle diagnosis or maintenance indication
Patent
1997-06-30
1999-12-21
Cuchlinski, Jr., William A.
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle diagnosis or maintenance indication
701 35, 701 66, 701 97, 340439, G06F 700
Patent
active
060061464
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to vehicle diagnostic method and apparatus, and in particular, to the vehicle diagnostic method and apparatus for communicating with an electronic control unit mounted on a vehicle to diagnose the vehicle based on the communication results. More specifically, it relates to the vehicle diagnostic method and apparatus capable of reducing restrictions on the sequence and timing of operations to be performed by an operator for each diagnostic item.
BACKGROUND ART
To improve engine control functions, an electronic control unit (ECU) with a microcomputer has been used in recent years for executing control programs, such as control of ignition timing in an engine, control of valve opening and closing timing, and/or control of fuel injection in an electronic fuel injector (EFI) for an automobile (hereinafter, referred to as a "vehicle"). The ECU is connected to sensors, such as a temperature sensor for detecting a temperature of engine cooling water, an engine-speed sensor for detecting an engine speed, a vehicle-speed sensor for detecting a vehicle speed, and an O2 sensor for detecting an oxygen concentration in exhaust gas. The ECU is also connected to switches such as a brake switch for detecting that a driver has stepped on a brake pedal. The ECU thus executes various kinds of controls based on detection signals output from the sensors and others.
On the production line where vehicles with such an ECU are manufactured, in the final test process after assembled, it should be diagnosed whether or not each of sensor and the like, and the ECU itself functions normally. For example, Japanese patent publication No. Hei 3-59372 proposes a diagnostic method in which a diagnostic apparatus with a microcomputer executes a vehicle diagnostic program to diagnose a desired diagnostic item at scheduled timing.
In a failure diagnosis related to a plurality of diagnostic items, for example, as disclosed in Japanese patent publication No. Sho 61-25091, the plurality of diagnostic items are diagnosed in predetermined order and the results of pass/failure or displayed judgment in respective diagnostic items are output one by one.
A typical checking (diagnostic) apparatus with a microcomputer is generally designed to make its display part show a menu screen when the operator turns on a power switch of the checking apparatus after connected to a machinery to be checked. On the menu screen, a list of many available functions is displayed, such as "Self-Diagnostic Function", "Memory Check Function" and "Mode Select Function", including a desired checking function. Then the operator selects a desired checking function through a key operation to start a test program for executing the selected checking function.
Some of such vehicle diagnostic items require particular preconditions. For example, an "Ne Diagnosis" to determine whether or not an engine speed Ne at idling time is in a given range or not must be executed under the condition that the engine has been warmed up adequately. Some other diagnostic items require no precondition and are allowed to complete the diagnosis for an instant, such as a "Brake Switch Diagnosis" to diagnose an opening and closing function of a brake switch. It should be noted that the "Ne Diagnosis" is automatically executed according to the program, and the operator has nothing to do during execution of this program but keep the engine idling.
When a vehicle diagnostic program is started, the result of the "Switch Diagnosis" can be obtained in a very short time after starting the diagnosis, but the "Ne Diagnosis" cannot be even started until the preconditions, such as to warm up the engine adequately, are satisfied. Therefore, even if the "Ne diagnosis" is not judged to be passed, it will require much operator's labor to determine whether the judgment is caused by a fault of the idling speed Ne or the diagnosis itself that has not been executed yet because the engine has not been warmed up adequately.
When such a plurality of diagnostic items are required, the se
REFERENCES:
patent: 4267569 (1981-05-01), Baumann et al.
patent: 5515272 (1996-05-01), Sakai et al.
patent: 5565856 (1996-10-01), Takeba et al.
patent: 5757645 (1998-05-01), Schneider et al.
Sasaki Kazumune
Usui Shigeru
Yokoi Hiroshi
Arthur Gertrude
Cuchlinski Jr. William A.
Honda Giken Kogyo Kabushiki Kaisha
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