JPS6060274A - Knock control device - Google Patents

Abstract

PURPOSE:To permit to effect stabilized control by a method wherein the value of wave height or the average value of a vibration wave of an internal-combustion engine in a predetermined operating area is compared with the maximum and minimum values of predetermined desired value and fail-safe control is effected when a range within the minimum and maximum values has been exceeded. CONSTITUTION:In the operating area, such as the area of idling operation for example, a waveform V1 is provided except the case in knocking area when a knock sensor 5 has a normal sensibility, therefore, the value of wave height of a signal A from a waveform shaping circuit 12 is supplied to a MCU9 through a sample hold means 13 and the value is compared with the maximum value VN1 and the minimum value VN2 of the desired value. In this case, the waveform V1 is within the range of limit values, therefore, a normal knock restricting control is effected. When the signal K from the knock sensor 5 is deviated from said range of limit values, it is judged that the sensibility of the knock sensor 5 is not suitable for the practical use and the predetermined fail-safe control is effected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an engine knock control system [6], and particularly relates to a knock detection sensor (hereinafter abbreviated as a knock sensor) and
The present invention relates to a fail-safe control device suitable for protecting a controlled object when the input signal path is in a state where the control is not affected by short circuits, disconnections, changes over time, etc. (4).

[Behind the invention L]

A known method for suppressing engine knocking is to detect engine knocking using vibration waves, determine the amount of retardation of ignition timing in response to the detected amount, and perform all ignition timing corrections.

Conventionally, among these devices, the conventional method was
- As seen in 61409, the amount of change in the bias potential to the knock sensor due to abnormalities in the knock sensor and signal path, such as short circuits and disconnections, or when the above abnormality occurs, the signal wave is significantly different from normal. The common method was to detect the phenomenon and correct the constant value.

According to this method, it is difficult to detect changes in the sensor over time, that is, deterioration in the stock index where the signal (ii) is not extremely different from the normal value. If this happens, the engine will be placed in a state that appears to be normal, and the control operation will be executed at a position where the knocking level is higher than normal, which may have an adverse effect on the engine.

On the other hand, in contrast to the phenomenon described above, if the vibration wave changes over time in the direction of the normal value, this signal will be detected as the entire knocking range even if the knocking is tolerable from the engine side, and the ignition timing will be corrected. As a result, there were drawbacks such as a reduction in the power performance of the engine.

[Purpose of the invention]

An object of the present invention is to eliminate the drawbacks of the prior art as described above, and to provide a knock control rHI device suitable for detecting knock sensor sensitivity inappropriate for knock control, performing fail-safe operation, and performing stable knock suppression. .

[Summary of the invention]

The main point of this invention ψJ is to compare the peak value or average value of the vibration wave in a predetermined operating range in the engine operating state, for example during idling, with a predetermined desired value, and
When AX<actual value<desired value MIN, that is, it is sensed that the knock sensor is out of practical sensitivity, and fail-safe control is performed.

[Embodiments of the invention]

Hereinafter, one embodiment will be described in detail according to the drawings.

An ignition plug 4 is disposed in the engine 1, and an ignition coil 3
Each cylinder receives the high R1 pressure generated by the engine, allowing each cylinder to ignite. 7 is a control device including a microcomputer (84 CU) 9, a band pass filter (Bf) 7. An amplifier 8 is built in, which indicates the operating status of the engine, such as a rotation angle sensor, etc. ? ? In response to issue (a) of the engine condition detector 11, the engine condition detector 11 is
Ignition mrJ that leads to an appropriate operating state for the engine
Apply the vI code to the ignition coil and turn the engine to 11 (l?'/ as if turning.

(7, Front-1-: On a part of the camphor i surface 6 of the engine J (
d. A knock sensor 5 for detecting knocking is installed, and this Ig is mounted on the control device base, and when knocking occurs, the ignition timing (*i) is This has been corrected to completely prevent knocking.

Fig. 2 shows a detection circuit obtained by closing the internal block of the control device according to the embodiment of the present invention shown in Fig. 1;
No. U ■ is connected to No. A 3 processing circuit 12 . The signal processing circuit 12 has a function of receiving the signal K from the knock sensor and outputting a waveform-shaped signal sequence (2) and a pulse wave signal (2) corresponding to the knock intensity when a knock occurs. This Shinzuki■ is the above-mentioned MCU9 through the sample bold means 13.
is connected to boat A. -The force signal ■ is also sent to the MCU
9 is connected to boat P. Also, the % corresponding sample bold means 13 is the sampling a from the above y, CU 9.
All signals ■ are connected.

The operation of the above solid control circuit will be explained using FIG. 3.

The signal 0 is the output signal of the knock sensor 5. When knocking as shown in the figure occurs in the range of knock sensor sensitivity in the normal state, the peak value of the signal ■ becomes sharp and the shinotsuguing waveform becomes 45.
The above-mentioned signal (2) is input to the signal processing circuit 12 and transmitted to the port P of the MCU 9 as an output. Inside the MCU 9, a counter operates from t in response to the pulse of the signal (2) and counts a predetermined value nf. Then, the 7 de ζ retarded discharge θl corresponding to the counter 1 shift 11 is calculated, added to the ignition timing θ+al during operation, and the next ignition timing is corrected as θIG1+ (-6,l) to suppress knocking. Execute processing.

This operation is performed in a manner that corresponds to the engine operating condition, and is executed repeatedly in sequence by counting the counter at the edge of the bow. . However, boiJa's own knock sensor 5
In this regard, for changes in the characteristic performance due to the inherent performance or changes over time, it is considered to be a practical area.
The amount that can be removed by 1 fill can be improved.

From this, by the five-order Mlj example, d], outside the knocking region: j'! For example, in the idling driving range, the signal of the knock sensor 5 in the part marked U in Fig. 3, that is, in the background, exhibits a vibration wave proportional to the knock vibration. Focusing on
The background signal shown in the figure [J] has a waveform of 1, which has a small node-sensitivity, and Vl, so the waveform has been shaped.
The wave height value of No. 8
eO2 is supplied and compared, the desired values VNI and VH2
is within the limit value range, and MeO2 is determined to be normal, and the above-mentioned regular knock suppression control is executed.

Now, when the signal (2) of the knock sensor 5 under the same conditions decreases, that is, when it becomes a signal wave v2, this signal is similarly supplied to MeO2 via the waveform shaping circuit 12 and the sample bold means 13. VNI and VH
2. As a result, it is determined that the shortness/length sensitivity is not suitable for practical use because it is outside the limit value, and based on this information, a predetermined correction amount θE is added to the current ignition timing θIG2, and the next ignition timing is set as θXG2+(- It is modified and executed as 〇E).

Also, although not shown, the sensitivity of the knock sensor is equal to the control value V.
The same control is performed for 1 hour for the field a which changes from N2 to the dog direction.

As described above, according to this embodiment, in which the practical sensitivity of the knock sensor is determined in a region other than the region where knocking occurs during engine operation to determine whether or not to perform knock suppression control, variations in the knock sensor and changes over time are determined. It is possible to quickly detect this and implement appropriate knock suppression control, which has great effects such as preventing serious accidents such as engine damage, as well as minimizing the reduction in engine output.

Further, as a modification of this embodiment, it is easily devised to add an alarm means such as a lamp when the above-mentioned situation becomes unusable.

〔Effect of the invention〕

According to the present invention, it is possible to show the user that the vehicle is in a state where it cannot be put to practical use, so new effects can be obtained, such as bringing out great advantages in terms of maintenance.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention, FIG. 2 is a diagram of a partial circuit 114 of the present invention, and FIG. 3 is an explanatory diagram of an operation time chart of the circuit shown in FIG. 2. . 1...Engine, 2...Control 1 device, 7...Band pass filter, 8...Additional 1
1'tVi device, 9...mypa) 1st Figure 7

Claims (1)

[Claims] 1. In a device that detects knocking that occurs in an engine using vibration waves and corrects and controls the engine's ignition timing, the signal level during a given operation is compared with a predetermined desired value, and the input signal level is determined to be the desired value. A knock control device characterized in that when the lower limit value or the upper limit value is exceeded, the closed loop suppression control of knocking is completely interrupted and the correction to the basic ignition timing is kept at a constant value.