JPH0613966B2 - Abnormality detection device for engine crank angle sensor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a device for detecting an abnormality of an engine crank angle sensor.

<< Background of the Invention >> For example, in a diagnostic device for an engine centralized electronic control system disclosed in Japanese Patent Laid-Open No. 56-141534, an abnormality of a crank angle sensor for detecting engine rotation is diagnosed using this type of device.

In the crank angle sensor, the engine crank angle is, for example, about 70 degrees before the piston top dead center, and the REF signal 10 in FIG.
0, and the POS signal 102 of FIG. 2 is obtained every time the engine crankshaft rotates by 2 °. In the conventional device, the cycle of the REF signal 100 becomes a cycle of a certain period or more or a certain period of time or more elapses. Even if the REF signal 10
When the generation of 0 is not recognized, or the REF signal 10
Engine speed and POS signal 1 calculated from 0 cycle
When there is a difference between the engine speed calculated from 02 and the engine speed, abnormality of the crank angle sensor is detected.

However, in the past, abnormality detection was performed without specifying whether the abnormality of the crank angle sensor occurred in the REF signal system or the POS signal system. Therefore, when the crank angle sensor is serviced and inspected thereafter. It is necessary to search for an abnormal point from both systems, which requires a lot of labor and time.

<Purpose of the Invention> The present invention has been made in view of the above conventional problems,
An object of the invention is to provide an abnormality detecting device for an engine crank angle sensor capable of identifying a signal system in which an abnormality has occurred.

<Configuration of the Invention> In order to achieve the above object, the present invention provides a constant angle pulse detection means for detecting a constant angle pulse generated by a crank angle sensor each time the engine crank angle reaches a predetermined angle, and a predetermined engine crank angle. A constant angle interval pulse detecting means for detecting a constant angle interval pulse generated by the crank angle sensor for each angle interval, and counting the number of constant angle interval pulses detected by the constant angle interval pulse detecting means, and First counter means for resetting the count value each time a pulse is detected, counting the number of constant angle interval pulses detected by the constant angle interval pulse detecting means, and the first counter means Each time the counted value reaches a predetermined number smaller than the number of constant angle interval pulses to be generated within the constant angle pulse generation interval, The second counter means for resetting the counter value and the number of constant angle interval pulses counted by the first counter means are greater than the number of constant angle interval pulses that should be generated within the constant angle pulse generation interval. When the number is large, the constant angle pulse system abnormality determining means for determining the abnormality of the constant angle pulse system of the crank angle sensor, and the count value of the second counter means is equal to the predetermined number. If the number of constant angle interval pulses is not reset because the number of constant angle interval pulses is not reached and the number of constant angle interval pulses is greater than the number of constant angle interval pulses that should be generated within the constant angle pulse generation interval, the constant angle interval pulse that determines that the crank angle sensor has an abnormal constant angle interval pulse system. And a system abnormality determining means.

<< Description of Embodiments >> Preferred embodiments of an apparatus according to the present invention will be described below with reference to the drawings.

The input terminal 10 of the embodiment apparatus shown in FIG. 1 is supplied with the REF signal 100 shown in FIG. 3 (A),
The respective pulses are generated at about 70 degrees before the top dead center of the piston of each cylinder.

The engine of this embodiment has six cylinders, and RE
The F signal 100 is generated once at an engine rotation angle of 120 °,
As can be understood from FIG. 3 (A), the pulse widths are different for each engine cylinder.

The REF signal 100 is directly output from the terminal 14 in FIG. 1 and is also supplied to the T input of the monostable multivibrator 10.

Q signal 1 obtained by the monostable multivibrator 10
04 is a REF signal 100 as shown in FIG.
With this, the pulse rises and has a predetermined width, and therefore each pulse of the REF signal 100 has a constant pulse width regardless of the cylinder.

Further, the Q signal 104 of the monostable multivibrator 12 is supplied to the R input of the binary counter 16, and its C input is supplied with the POS signal 102 from the crank angle sensor.
Is supplied via the input terminal 18.

In this embodiment, as understood from FIG. 3 (C), RE
During each generation interval of the F signal 100, this POS signal 1
The number of pulses generated in 02 is 60.

Thus, since the REF signal 100 is supplied to the R input of the binary counter 16 via the monostable multivibrator 10 and the POS signal 102 is supplied to its C input, each time the REF signal 100 rises, that is, the POS signal. When the pulse count value of 102 reaches 60, the count value of the binary counter 16 is reset to 0.

In this binary counter 16, the seven-digit signals Q ₀ , Q ₂ , Q ₄ , Q ₈ , Q ₁₆ , Q ₃₂ from the lowest count digit side,
Q ₆₄ is obtained, and signals other than the signal Q ₆₄ of the highest count digit are supplied to the count number determination circuit 20.

The count number determination circuit 20 includes AND circuits 22, 2
4 and 26 are provided, the signal Q ₀ is input to the first AND input of the AND circuit 22 via the inverter 28, the signal Q ₂ is input to the second AND input, and the signal Q ₄ is input to the third AND input.
Are supplied respectively.

The signal Q ₀ is input to the first AND input of the AND circuit 24 via the inverter 28, and the signal Q ₂ is input to the second AND input.
There are respectively supplied, the signal Q ₈ and more first AND input of the AND circuit 26, the second AND input signal Q ₁₆
However, the signal Q ₃₂ is supplied to each third AND input.

Of these, the AND signal of the AND circuit 22 and the AND circuit 26
The AND signal of is supplied to both AND inputs of the AND circuit 30, and the AND signal of the AND circuit 30 is given to the output terminal 32 as the abnormality detection signal 106.

As can be understood from the above description, the binary counter 1
When the pulse count value of the POS signal 102 according to 6 becomes 62, the abnormality detection signal 106 is given from the AND circuit 30 to the output terminal 32.

The count number determination circuit 20 is provided with an AND circuit 34, and the AND circuit 2 is connected to the first AND input of the AND circuit 34.
An AND signal of ₄ is supplied to the second AND input of the signal Q ₄ of the binary counter 16 via the inverter 36, and an AND signal of the AND circuit 26 is supplied to the third AND input thereof.

As a result, the AND signal 108 of the AND circuit 34 becomes "1" when the pulse count value of the POS signal 102 by the binary counter 16 becomes 58.

The AND signal 108 is supplied to the R input of a binary counter 38 having the same configuration as the binary counter 16, and the POS signal 102 is supplied to the C input thereof via the input terminal 18.

Therefore, in the binary counter 38, the AND circuit 3
The AND signal 108 of 4 causes pulse counting of the POS signal 102 until the count value reaches 58, and this is repeated.

However, when the count value becomes 64, the signal Q ₆₄
Is given to the output terminal 40 as the abnormality detection signal 110.

The POS signal 102 is supplied to the T input of the retriggerable monostable multivibrator 42 via the terminal 18, and the Q signal 112 is supplied to the output terminal 44.

Further, the output terminals 14, 32, 40, 44 are connected to an intermittent failure recording device for recording the signals given to them in a unit of several seconds, and in the event of an abnormality, the recorded data thereof are used by the diagnostic device of the engine centralized electronic control system. It is referred to and repaired and inspected according to the diagnosis result.

The present embodiment is configured as described above, and its operation will be described below.

In Fig. 3, the crank angle sensor is operating normally and REF
When both the signal 100 and the POS signal 102 are normally input, the pulse count value of the POS signal 102 counted by the binary counter 16 is 59.
The pulse count number never reaches 62 because the REF signal 100 rises immediately before and after 60.

Therefore, as shown in FIG.
The abnormality detection signal 106 of 0 remains “0” and becomes “1”.
It never becomes.

Further, when the pulse count number of the POS signal 102 by the binary counter 16 becomes 58, the AND signal 108 of the AND circuit 34 becomes "1" as shown in FIG. The pulse count value of the POS signal 102 is forced to 0
Therefore, the pulse count value never becomes 64.

Therefore, as shown in FIG. 3 (F), the abnormality detection signal 110 of the binary counter 38 remains "0".

As described above, during normal operation of the crank angle sensor, the abnormality detection signal of "1" is not output from the output terminals 32 and 40.

Here, if some abnormality occurs in the REF signal system and the REF signal 100 and the Q signal 104 which should rise at time t ₁ are missing as shown in FIGS. 3 (A) and 3 (B), for example, the binary counter POS signal 1 by 16
The pulse count of 02 is continued as it is, the pulse count value reaches 62, and as a result, the abnormality detection signal 106 of the AND circuit 30 becomes "1" as shown in FIG. 3 (D).

If the REF signal 100 does not continue to occur after that, the binary counter 16 outputs the POS signal 1
Since the count of 02 is continued, the abnormality detection signal 106 output from the AND circuit 30 repeats "1" and "0" every time 32 pulses are counted.

When the REF signal system is abnormal, the binary counter 38 is reset every time the pulse count number of the POS signal 102 reaches 58. Therefore, as shown in FIG. 3 (F), the abnormality detection signal 110 is " The state of "0" is maintained.

As described above, in this embodiment, the abnormality of the REF signal system is detected by the abnormality detection signal 106 of the AND circuit 30 output from the terminal 32.

On the other hand, for example, when the crank angle sensor has an abnormality in the POS signal system in which the 56th to 59th pulses of the POS signal 102 are temporarily missing from time t ₂ to time t ₃ in FIG. 3C. , P by the binary counter 16
Before the pulse count value of the OS signal 102 reaches 58, the pulse count value is forcibly set to 0 by the REF signal 100.
It is said that

Therefore, as shown in FIG. 3 (E), the AND circuit 3
The AND signal 108 of 4 remains "0", and the binary counter 38 is not reset.

Therefore, when the POS signal 102 recovers from the 60th pulse at time t ₃ , the binary counter 38 restarts the pulse counting of the POS signal 102 from 56, and then the 8th pulse of the POS signal 102 in the next cycle of the REF signal 100. Is counted by the counter 38, the Q of the binary counter 38 is changed as shown in FIG.
_{The 64} signal 110 becomes “1”.

Note that during that time, the binary counter 16 is reset by the REF signal 100, so that FIG.
As shown in FIG.
Is left as "0".

In this way, when an abnormality occurs in the POS signal system, the abnormality detection signal 110 of "1" is output from the terminal 40 from the binary counter 38 to the output terminal 40.

When the REF signal 100 is continuously lost, the abnormality is detected by the signal 100 output from the terminal 14.

At this time, since the POS signal 12 is counted by the binary counters 16 and 38 despite this, abnormality detection of the POS signal system is normally performed.

For that purpose, it is preferable to make the pulse width of the Q signal 104 sufficiently short to reset the binary counter 12.

Also, as shown in FIG. 3 (C), the POS signal 1
When 02 is continuously lost, the Q signal 112 of the retriggerable monostable multivibrator 42 becomes "0" as shown in FIG. 3 (G), and therefore such anomaly detection is also possible. For that purpose, it is preferable to set the time constant of the retriggerable monostable multivibrator 42 that outputs the Q signal 112 so that the Q signal 112 always holds “1” in a normal state.

As described above, according to this embodiment, the REF signal 10
It is possible to determine whether the REF signal system has an abnormality or the POS signal system has an abnormality depending on the number of pulses of the POS signal 102 generated in one cycle of 0. Therefore, the result can be used thereafter. For example, it becomes possible to easily find the location of the abnormality in a short time.

Further, according to the present embodiment, the pulse width of the REF signal 100 is converted to a constant pulse width regardless of each cylinder, so that the REF signal 100 continues to be in the state of "1" due to the disconnection of the wire harness or the like. Even if an abnormality of the signal system occurs,
It is possible to continuously detect the abnormality on the POS signal system side, and it is also preferable to continue the engine control using the count value of the POS signal 102.

<< Advantages of the Invention >> As described above, according to the present invention, the number of constant angle interval pulses counted by the first counter means is the number of constant angle interval pulses that should be generated within the constant angle pulse generation interval. If there are more, the constant angle pulse system abnormality determination means for determining the abnormality of the constant angle pulse system of the crank angle sensor and the count value of the second counter means do not reach the predetermined number. If the number of constant angle interval pulses is not reset and the number of constant angle interval pulses is larger than the number of constant angle pulse occurrence intervals, it is determined that the crank angle sensor constant angle interval pulse system is abnormal. Since the means is provided, the constant angle pulse (R
It is possible to determine whether an abnormality has occurred in the EF signal) system or in the constant angle interval (POS signal) system. Therefore, if this result is used thereafter, the location of the abnormality can be easily and quickly. It will be possible to discover it.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing a preferred embodiment of the device according to the present invention, FIG. 2 is a waveform diagram showing the relationship between the REF signal and the POS signal, and FIG. 3 is a diagram for explaining the operation of the embodiment shown in FIG. It is a timing chart. 12 ... Monostable multivibrator 16 ... Binary counter 20 ... Count number determination circuit 38 ... Binary counter 42 ... Retriggerable monostable multivibrator

Claims (1)

[Claims] 1. A constant angle pulse detection means for detecting a constant angle pulse generated by a crank angle sensor every time the engine crank angle reaches a predetermined angle, and a constant angle pulse detection means generated by the crank angle sensor at predetermined angle intervals of the engine crank angle. Constant angle interval pulse detecting means for detecting the angle interval pulse, and counting the number of constant angle interval pulses detected by the constant angle interval pulse detecting means, and the count value is calculated every time the constant angle pulse is detected. The number of constant angle interval pulses detected by the first counter means to be reset and the constant angle interval pulse detecting means is counted, and the count value counted by the first counter means is the constant angle pulse. Second counter in which the count value is reset each time a predetermined number smaller than the number of constant angle interval pulses to be generated within And the constant angle interval pulse counted by the first counter means is greater than the number of constant angle interval pulses that should be generated within the constant angle pulse generation interval, the constant angle of the crank angle sensor. The constant-angle pulse system abnormality determining means for determining an abnormality in the pulse system and the count value of the second counter means are not reset because the count value of the first counter means does not reach the predetermined number, and the constant value is not set. If the number of constant-angle-interval pulses to be generated within the angle-pulse generation interval is greater than the number of constant-angle-interval pulses, the constant-angle-interval pulse system abnormality determination means for determining an abnormality in the constant-angle-interval pulse system of the crank angle sensor should be provided. Characteristic engine crank angle sensor abnormality detection device.