JP3107454B2 - Fault storage device in automobile control unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for storing a failure in a control device of a motor vehicle.

The control unit can be a single control unit of the motor vehicle, an individual control unit which operates independently of the other control units with respect to the storage of faults, or a plurality of control units having a common fault storage unit. It can be a combination. In the following, for the sake of brevity, a single control device will be described, and in the embodiment the control device shall be used to control the operating sequence of the internal combustion engine. However, as is evident from the detailed description, the information stored in the specific information content is not important, so all that will be described using a single control device of the internal combustion engine will be used for other functions of the vehicle. It can be used for devices related to driving groups (eg brakes, chassis, transmissions, safety devices).

[0003]

2. Description of the Related Art Conventionally, when a failure lasts longer than a predetermined period, the failure is recorded in a failure memory. This time period is typically a few seconds, the specific time period being associated with each failure. In today's advanced automotive electronics, the test process is clearly performed for more than a hundred types of failures. However, the fault memory does not have a storage location for storing all possible faults. It is unlikely that all these failures will occur before the driver arrives at the factory. Storage locations are provided for, for example, 20 to 30 failures. A single time counter is used to measure how long a fault exists. Typically, the second fault that occurred while the first fault continued is that the time counter is set to the first time when the fault has disappeared or a predetermined period set for the fault has elapsed. Is processed only when it is no longer necessary to handle the failure. In another example, the counter is restarted each time a fault occurs, and after the latest set period has elapsed, all faults still present at that point are recorded in fault memory.

[0004] In a previous application (DE-A-4040927) it has been proposed to provide a storage location for a time counter in the fault memory for each fault and to record whether the counter has already elapsed. I have. Each time a failure occurs, failure information is recorded in the failure memory, and the time set for the failure is set in the time counter storage location. At the same time, it is recorded in the fault memory whether the time counter has not yet elapsed. This information is used to prevent access to the fault storage location to prevent the fault from being used as the fault itself. Subsequently, the time counter is decremented. After the time of the time counter has elapsed, the fault is permanently recorded in a callable manner, since the above-mentioned information is correspondingly changed.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fault storage device in a control unit of a motor vehicle, which requires only a few storage locations, but makes it possible to handle simultaneously occurring faults individually. That is.

[0006]

In order to solve the above-mentioned problems, a device according to the present invention for storing a fault in a control device of a motor vehicle has the following functional units, that is, m time counters (m> 1). A failure time counting device having
A fault memory for storing information for a number of faults (n> m), and when the fault continues beyond a test period set for the fault, the fault is callably permanent. Will be recorded.

[0007]

The number m of the time counter is preferably chosen to correspond, in a typical case, to the maximum number of faults which occur simultaneously during the operation of the motor vehicle. In that case, it should be noted that a transient state similar to a failure occurs in the unsteady state of the operation of the vehicle device. The time period associated with the individual faults will only fail for those faults which have been shown to be, in fact, permanent faults and not transient faults during short non-stationary periods by exceeding the above-mentioned periods. It is chosen to be recorded in memory.

In actual use, for example, 120 faults can be inspected, 30 faults have storage locations in the fault memory, and four faults have their fault periods counted simultaneously by the fault time counting device. Can be inspected. Thus, all possible faults can be dealt with individually at the same time, and there is no need to provide a time counter location for each fault in each area of the fault memory.

In some way, a time counter must be associated with a fault whose time is counted by the counter. This association is made possible by each time counter having a period storage location and a fault identification storage location. The failure identification is typically a failure number.
Seven bits are needed to distinguish 120 faults, and 8 bits from 127 faults, so, due to the possibility of byte addresses, a typical memory is 1 bit each.
Requires bytes. Therefore, when there are four time counters, the failure identification memory requires 4 bytes or 32 bits.

Another possibility of the memory in the above association is that each time counter has a period storage location and the fault memory has a storage location for storing a time counter number for each fault. If there are four time counters, two bits are enough to distinguish these four time counters. If the total number of faults that can be stored is 30,
You have to prepare 60 bits. Although the number of bits is increased in the above example, this arrangement still has advantages. Allocating two bits for the time counter without requiring additional storage space, since there are variously processed bytes in the bit memory that are not yet fully utilized in the faulty memory Because it can be.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1 shows a block diagram of a RAM 10 of a control device (not shown) of a motor vehicle. RAM is
In particular, it has an area used as the fault memory 11 and an area functioning as the fault time counting device 12.

First Embodiment of Failure Time Counting Apparatus 1
2.1 is shown in detail in FIG. This device has four counters (m = 4) Z1 to Z4 each having a period storage location (time storage location) and a fault identification storage location. In the period storage location, periods T1, T2 and T4 are stored. The associated fault numbers are FN1, FN2 and FN
4. The numbering of the period and the failure number indicates the order in which this data reaches the failure time counting device 12.1. This can also be understood from the time periods shown in the examples. That is, the period T1 is only one second left, ie the first set, for example 5 seconds, has almost passed, while the period T4 with 4 seconds is still relatively long, and thus has just been set or, for example, 6 seconds. Some time has passed since the period. Third data in storage order,
That is, the period T3 and the failure number FN3 have already been erased, for example, because they have disappeared immediately after the occurrence of the corresponding failure.

Failure time counting device 12.1 shown in FIG.
When a new failure occurs from the memory state of the above, the initialized time counter is searched. In the case of FIG. 2, this is a time counter Z3. Here, the values T5 and FN5 are stored. Which counter is free as the next counter depends on which fault continues or which fault disappeared from the counter before the set period of time had elapsed when the fault occurred. If all faults continue, in the situation shown in FIG. 2 the period of the time counter Z1 first expires, which is then initialized and is therefore used to store new data.

The memory structure shown in FIG. 2 has the disadvantage that every time a fault occurs, the entire fault time counter 12.1 must be searched to find a free time counter. If all counters are running and none are empty, all time counters must be checked before knowing the status of the counters.

This disadvantage does not exist in the counter structure shown in FIG. Failure time counter device 1 shown in FIG.
2.2 has a counter pointer storage location P in addition to the four time counters Z1 to Z4 which function in the same manner as described with reference to FIG. Here, the address of the first vacant time counter, for example, the counter Z4 is stored. This address has a size of 2 bytes. One byte is used for each of the period storage location and the failure identification storage location of each time counter.

In the case of this memory structure, it is necessary to rewrite the contents of the time counters having higher numbers to the time counters having the next lower numbers whenever any one of the counters elapses. At this time, the address stored in the storage area P is decremented by one address value (here, 2 bytes). With such a configuration, in the fault time counting device 12.2, the periods T1, T2 and T4 of the counters which are continuous with each other are continuous with each other, but in the fault time counting device 12.1 having a different configuration, the order T1, T4 and T2 follows the order in which the counters that were free at the time of the failure occurred were discovered.

During the presence of a fault, the duration of the associated duration storage location must be decremented. The association of each fault with its associated period is provided in the fault time counting devices 12.1 and 12.2 by providing each time counter with a period storage location and a fault identification storage location.

Another relation between the failure and the period will be described with reference to FIG. In the present embodiment, the fault time counting device 12.3 has only a time counter having a period storage location. Also in this case, the four counters Z1 to Z
4 are provided. Setting the period in the counter is the same as in the case of the failure time counting device 12.1 shown in FIG.

The fault memory 11 also shown in FIG.
It has n storage areas F1 to Fn for the number of failures (n = 30). Each fault storage area has a capacity of 4 bytes, the first byte has a fault number, the second byte has data on the type of fault, and the other two bytes have, for example, a short circuit in a conductor of an air weight sensor. For example, data relating to the first and second operating variables, such as data relating to the number of revolutions and load when a failure such as a fault occurs, is stored. The fault type byte is bit-aligned, i.e. each individual bit provides individual data. In the illustrated embodiment, the first
The state of the bit indicates whether the inspection time has elapsed. The next two bits are the failure time counting device 1
Indicates the counter number of 2.3. The fourth bit indicates whether a fault exists in the current operating cycle, the fifth bit indicates whether a warning lamp should be lit for the fault, and the other three bits each indicate other information.

When a fault occurs in the fault structure shown in FIG. 4, this fault is stored in the area next to the already occupied area, and whether the time counter of the fault time counting device 12.3 is empty is determined. Is checked. In the illustrated embodiment, Z3 satisfies this condition. In this case, a check period related to the fault that has occurred at that time, for example, read from the table is stored in this counter, and the counter number is stored in bits 2 and 3 of the byte of the fault type. The first bit is reset, thereby indicating that the test period is passing. While this bit is reset, the stored fault will not be called as a fault by the fault routine. If the fault is removed before the set time has elapsed, the fault record is erased and the fault counter Z3 is initialized, ie set to the value zero. If, on the other hand, the test period has elapsed, the first bit of the fault type is set, so that the fault recorded can be called up by all routines. The associated counter (here counter Z3) is initialized simultaneously with this passage of time, so that its value is zero.

When the embodiment shown in FIG. 4 is modified in the same manner as the embodiment shown in FIG. 3, that is, when an address pointer is used in addition to the fault time counting device, the counter becomes empty and a larger value is used. Whenever the value of the counter is transferred to one of the smaller counters, the counter number stored in the fault type byte must be corrected accordingly.

In the embodiment, it is assumed that the failure time counting device is formed in the RAM of the control device. However, it is also possible to use a register device provided separately.

The fault time counting device does not necessarily have to have four time counters, and the number of time counters is
The inspection times for a typical total number of simultaneously occurring faults may be selected so that they can be monitored individually. The typical total number of simultaneously occurring faults is particularly related to the number of faults monitored as a whole and the sensitivity in monitoring. It is much less than the number of faults provided at the fault storage location for faults.

The description of FIG. 4 assumes that information about any fault is stored in 4 bytes. However, it is also possible to store more or less information for each fault. The content and amount of information does not matter here, only that the fault time counting device is provided with a smaller number m of time counters for a large number of n faults that can be stored. is important.
This arrangement has the advantage that it is possible to individually monitor the associated test periods for faults which usually occur simultaneously, without the need for the same number of time counters as faults that can be stored.

[0026]

As is apparent from the above description, according to the present invention, a fault is stored in the control unit of a motor vehicle which requires only a small storage space, but can deal with faults occurring simultaneously. An apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram schematically illustrating a RAM used for storing a failure in a control device of an automobile.

FIG. 2 is an explanatory diagram schematically showing the contents of a failure time counting device having four time counters.

FIG. 3 is an explanatory diagram similar to FIG. 2, but illustrating a failure time counting device having four time counters and a pointer storage area.

FIG. 4 is an explanatory diagram of a failure time counting device provided with four time counters each having only a time storage location and a failure memory.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 RAM 11 Failure memory 12 Failure time counter Z1-Z4 Time counter

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Alvin Lutz Germany 7145 Markgrey Ningen Schäferweg 15 (72) Inventor Walter Schalfe Germany 7140 Ludwig Hissburg 11 Hohenreinstraße 20 (72) Invention Reiner Sommer German Federal Republic of Germany 7000 Stuttgart 31 Grouterstrasse 20 (56) References JP-A-2-133261 (JP, A) JP-A-63-221228 (JP, A) JP-A-58-84310 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01M 17/00-17/10 B60R 16/02 650 G05B 23/02-23/02 302

Claims (4)

(57) [Claims] 1. A fault time counting device (12) for detecting each period during which a fault continues, and a fault memory (11) for storing information for n faults.
A fault memory in the control unit of the motor vehicle, in which the fault is permanently and callably recorded when the fault lasts beyond a test period set for the fault, 1 <m <N, the failure time counting device (12) is m
A fault storage device in a control device for an automobile, comprising: a plurality of time counters (Z1 to Z4). 2. The apparatus according to claim 1, wherein each time counter has a period storage location and a fault identification storage location. 3. The system according to claim 1, wherein each time counter has a storage location for storing a time period, and the fault memory has a storage location for storing a time counter number for each fault. An apparatus according to claim 1. 4. The failure time counting device (12.2)
4. The device according to claim 1, comprising a storage area (P) for storing a first free time counter (Z4).