Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle diagnosis or maintenance indication
Reexamination Certificate
2001-12-21
2002-11-05
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle diagnosis or maintenance indication
C701S029000, C701S032000, C701S033000, C701S034000
Reexamination Certificate
active
06477453
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This application is based on and incorporates herein by reference Japanese Patent Application No. 2000-402415 filed on Dec. 28, 2000.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a programming technique for a self-diagnostic function in a controller for controlling a vehicle.
2. Description of Related Art
In general, the rapid progress of computer techniques in recent years has brought about the introduction of computer systems in every aspect of a vehicle, such as an automobile.
Particularly, a computer system for controlling a vehicle to assure higher reliability has been improved by including a self-diagnostic or self-diagnosis function. It is now possible for a vehicle to execute a diagnostic process for automatically checking operating conditions of a computer unit and its sensors or the like. This is done in an adequate time period by lighting a warning lamp (MIL), when a fault occurs therein. This notifies the occurrence of the fault to the user and/or stores the fault code (DTC), which allows a maintenance person to identify the nature of the fault. This diagnostic process aides about 200 items currently covering the sensors, such as: a crank angle sensor, a cam angle sensor, a water temperature sensor, or the like. The object of this diagnostic process is called the “diagnosis object” or “diagnostic object.”
In the design stage of the self-diagnostic program, to realize this diagnostic process, it must be realized that the diagnostic object is changed depending on car models, a grade of a car, and/or timing of model changes. Therefore, the fault detection logic is generally described for each diagnostic object in the self-diagnostic program. Therefore, if the diagnostic object is changed, depending upon the change, the change may be covered by changing only the corresponding fault detection logic.
Programming focused on a “thing” such as a diagnostic object is well known as “object-oriented programming.” A change in units of an object can be realized for a change of the diagnostic object. The object which does not require any change can be reused by structuring the object in units of fault detection logic.
In this specification, the expression an/the “object executes . . . ” in which the term “object” is the subject of a sentence is often used but it means that an operation of the object is executed when a CPU provided in the vehicle controller executes the program installed in the object.
The fault detection logic explained above is usually repeatedly executed by predetermined timing, in which timing a plurality of fault detection logics should be executed. This has been described in a platform (hereinafter, referred to as “PF”) as a program of a lower hierarchy.
Meanwhile, when the diagnostic object is changed, the execution timing of the fault detection logic may also be changed in some cases. Therefore, a program structure which provides an independent scheduler program (scheduler) for discriminating the execution timing from the PF has also been proposed. Therefore, there is merit that the change in execution timing can be covered easily by changing the scheduler.
However, for execution of a part of the fault detection logic, the timing and predetermined conditions must be considered. Namely, even when the execution timing is discriminated, situations exist in which executions should not occur. This is because of the condition that the fault detection logics are related to each other.
In some cases, the corresponding fault detection logic and a relationship with the correction of the fault detection logic are required for a change in the diagnostic object or the change in the execution timing. This correction will be explained below.
For example, when the first sensor is deemed defective, a fault of a second sensor in relation to the first sensor cannot be determined in some cases. In particular, an air-flow sensor for measuring the amount of intake air in the engine can be diagnosed accurately only when the intake air temperature sensor for detecting the intake air temperature is diagnosed as normal.
Moreover, a detected value of the first sensor is used for a diagnostic process of the second sensor in some cases. In particular, for the diagnostic process of the intake air temperature sensor explained above, or for detection value of a throttle sensor for detecting an opening of a throttle valve that is driven by an accelerator pedal.
As explained above, an execution condition for insuring the fault diagnosis result of the diagnostic object exists in some cases, and this execution condition is determined by the fault detection logic. The determination logic of the execution condition depends on other fault detection logic.
In this program structure, when fault detection logic corresponding to a certain diagnostic object is changed, it has been requested to review all fault detection logic relating to the above fault detection logic. In the example explained above, if fault detection logic of a throttle sensor is changed, the fault detection logic of the intake air temperature sensor and the fault detection logic of the air-flow sensor in relation to the intake air temperature sensor, have to be changed as required or as necessary.
Therefore, an extraordinary long time has been required in some cases to change the self-diagnostic program and it has lowered the re-utilization property. Moreover, if the change becomes large in scale, a possibility for generating a discrepancy in the program also becomes large and therefore the quality of the self-diagnostic program may be lowered.
The present invention has been proposed to overcome the problems explained above. It is therefore an object of the present invention to provide the controller for a vehicle having the self-diagnostic function with the ability to execute the fault detection of the diagnostic object with appropriate timing. Another objective is to assure change of the self-diagnostic program to realize the self-diagnostic function which contributes to quality improvement of the self-diagnostic program. This is so even if it is required to correct the execution condition of the fault detection due to a change in the diagnostic object.
SUMMARY OF THE INVENTION
In order to achieve objects of the invention, a controller for a vehicle is provided with the self-diagnostic function for automatically detecting a fault of the diagnostic object.
The fact that the self-diagnostic program is to realize this self-diagnostic function is based on the precondition that the fault detection logic, to detect a fault of the diagnostic object, is described through division thereof in a unit related to the diagnostic object. The unit of the diagnostic object is determined for each diagnostic object or for each fault detection process. The diagnostic object corresponds to the fault detection process almost on a one to one basis, but the diagnostic object of a common fault detection process can also exist. Therefore, it is preferable to provide the detection logic for every fault detection process from a point of view of providing a compact self-diagnostic program.
Under the pre-condition explained above, the determination logic of the execution condition when executing the fault detection logic based on an external timing signal is described simultaneously, but separately from the fault detection logic. For example, the determination logic of the execution condition is described as an exclusive program.
The self-diagnostic program is an object-oriented design and is structured in units of objects allowing reuse with inclusion of the fault detection object for detecting; a fault of the diagnostic object, a scheduler object, and a drive determination object. The fault detection object is prepared for every unit in relation to the diagnostic object.
In this case, the scheduler object determines the fault detection object as a drive object based on the external timing signal. Therefore, the drive determination object determines whether the fault detecti
Maki Yoshiyuki
Oi Masaya
Cuchlinski Jr. William A.
Denso Corporation
Marc-Coleman Marthe Y.
Nixon & Vanderhye P.C.
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