JPS6325178B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine vibration detection device.

Generally, in an automobile engine, a roughness sensor detects the roughness state (engine vibration) of the engine, and various driving state control devices that control the engine operating state suppress the roughness according to the detection output of the roughness sensor. There is one that controls the direction. An example of such a device is one that performs feedback control on the idle speed so that engine vibration converges within a certain range, thereby improving fuel efficiency, improving exhaust gas conditions, and preventing warm-up delays. (Unexamined Japanese Patent Publication 1973-
(Refer to Publication No. 91623), or in a multi-cylinder engine that performs cylinder reduction operation by stopping fuel supply to a specific cylinder depending on the engine load, when engine vibration increases, the engine cylinder reduction operation is stopped. There is a device designed to reduce engine vibration (see Japanese Utility Model Application No. 54-183521).

By the way, the causes of roughness in an engine include fluctuations in the air-fuel ratio and exhaust gas recirculation amount, or the occurrence of misfires, among which continuous roughness usually occurs due to fluctuations in the air-fuel ratio and exhaust gas recirculation amount. It is something. On the other hand, an engine misfire is a phenomenon in which normal combustion is not performed accidentally due to some reason, and even if this phenomenon is left untreated, normal combustion will immediately return. This misfire causes so-called one-shot roughness.

However, with conventional devices, roughness control is performed by detecting not only continuous roughness but also single-shot roughness, and when performing roughness control for single-shot roughness in this way, the control system has no control. Since there is a delay, this results in overcontrol, which has the disadvantage of making the engine operating condition unstable. That is,
If the conventional device described above were to control the idle speed, this overcontrol would cause the engine speed to fluctuate, and this fluctuating state would continue for a while (hunting). If it were to be controlled, it would switch from reduced-cylinder operation to full-cylinder operation, and then immediately switch back to reduced-cylinder operation, which would cause problems that were extremely undesirable in terms of feeling for the driver.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and it is possible to determine whether or not the engine vibration is caused by a single-shot roughness due to a misfire, based on the degree of damping of the engine vibration. It is an object of the present invention to provide an engine vibration detection device that can always perform optimal roughness control by stopping roughness control when it is determined that the roughness is a target roughness.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an engine vibration detection device according to an embodiment of the present invention. In the figure, 1 is a vibration detector that detects the magnitude of engine vibration, 2 is a roughness detection circuit that detects engine roughness from the output of vibration detector 1, and 3 is a roughness detection circuit that receives the output of roughness detection circuit 2 and outputs a roughness control signal. Generated control circuit, 4
5 is a roughness control device composed of the circuits 2 and 3, and 5 is an actuator (various operating state control device) that receives the roughness control signal and changes various parameters governing the operating state of the engine in a direction to suppress roughness. It is. Here, the various operating state parameters controlled by the actuator 5 include the air-fuel ratio, the amount of exhaust gas recirculation, the idle speed, and the ignition timing.

Further, 6 is a damping discrimination device which receives the output of the vibration detector 1 and discriminates whether or not the engine vibration is attenuated with a damping degree higher than a set value, or whether it is simply a one-off roughness; 7 is a damping discrimination device 6; This is a correction device that receives the output and stops the roughness control by the roughness control device 4 described above.

FIG. 2 shows the detailed circuit configuration of the above device. In the roughness detector circuit 2, 8 is the vibration detector 1
A bandpass filter (hereinafter referred to as BPF) that passes only the roughness signal component of the detection signal of , 9 is a double-wave rectifier circuit that double-wave rectifies the output a of BPF 8, and 10 is the output b of the double-wave rectifier circuit 9. and a reference voltage E; 11 is an inverter connected to the output of the comparator 10; 12 holds the maximum output value of the double-wave rectifier circuit 9, and is synchronized with the fall of the output of the inverter 11; This is a peak hold circuit that is reset by In the control circuit 3, 13 is the output e of the peak hold circuit 12.
14 is an integration circuit that integrates the output of the subtraction circuit 13, and 3a is an output terminal of the control circuit 3.

In the attenuation discrimination device 6, 8 and 9 are the above-mentioned BPF and a double-wave rectifier circuit, 15 is a comparator that compares the output a of the BPF 8 and the reference voltage (earth potential), and 16 and 17 are the comparator 15. Inverters 18 and 19 connected to the output c are connected to the output b of the double-wave rectifier circuit 9, and are reset in synchronization with the fall of the output c of the comparator 15 or the output of the inverter 17 to This is a peak hold circuit that holds the maximum output value of the wave rectifier circuit 9. 20,2
1 is an analog switch that opens and closes according to the output of the inverter 16 or the output c of the comparator 15 and disconnects the input from the double-wave rectifier circuit 9 to the peak hold circuits 18 and 19; 22 is the output e of the peak hold circuit 12; The differential amplifier circuits 23 and 24 which operationally amplify the difference between the outputs f of the peak hold circuits 18 and 19 and the outputs f of the peak hold circuits 18 and 19 open and close according to the output c of the comparator 15 or the output of the inverter 17. An analog switch 25 connects and disconnects the input to the differential amplifier circuit 22, and a comparator 25 compares the output of the differential amplifier circuit 22 with a reference voltage E. Further, 26 opens and closes according to the output of the comparator 25, and the subtraction circuit 1
The analog switch 26 is an analog switch that connects and disconnects the input from the first integration circuit 14 to the first one.
This constitutes the correction device 7 shown in the figure.

Next, the general operation of this device will be explained.

In this device, the vibration detector 1 constantly detects the magnitude of engine vibration, and when roughness occurs in the engine, the detection signal of the vibration detector 1 contains signal components other than roughness, such as DC components. Therefore, in the roughness control device 4 , the roughness detection circuit 2 extracts only the roughness signal component from the output of the vibration detector 1 and applies it to the control circuit 3 . This control circuit 3 generates a roughness control signal according to the roughness level of the engine and applies it to the actuator 5, which controls various parameters governing the engine operating state, such as the air-fuel ratio, to suppress the roughness. direction, which brings the engine into a stable operating state.

However, when a single roughness occurs due to a misfire, if the roughness control is performed as described above, the roughness control becomes overcontrolled due to the control delay of the control system, and the operating state of the engine becomes unstable. However, in this case, in this case, the damping determination device 6 receives the output of the vibration detector 1, determines whether the degree of damping of the engine vibration is equal to or higher than the set value, that is, whether the engine vibration is one-off roughness, and performs correction. Device 7
receives the output of the damping discriminator 6 and stops the roughness control for the one-shot roughness by the control circuit 3, so that the roughness control of the engine does not become over-controlled, and therefore the optimum roughness control is always performed. The engine is maintained in stable operating condition.

Next, the operation will be explained in detail using FIG. Here, FIG. 3 a to f show the BPF 8, double-wave rectifier circuit 9, comparator 15, inverter 11, peak hold circuit 12, and peak hold circuits 18 and 1 of this device.
9 is an output waveform diagram of No. 9.

When the vibration detector 1 detects the vibration of the engine 1a, the BPF 8 in the roughness detection circuit 2 receives the output of the vibration detector 1 and detects the roughness signal component a.
(see Figure 3a), and the double wave rectifier circuit 9
The output a of BPF8 is double-wave rectified, and it is sent to comparator 1.
0 and peak hold circuit 12. The comparator 10 receives the output b of the double-wave rectifier circuit 9 (see FIG. 3b).
is compared with the reference voltage E (see Fig. 3b, one-dot chain line), and when the output b is lower than the reference voltage E, it becomes "1".
Therefore, the inverter 11 inverts the output of the comparator 10. Peak hold circuit 12 is inverter 1
1 receives the inverted signal of the output d (see Figure 3 d),
Since the peak hold circuit 12 is reset in synchronization with the rise of the output d, each time it is reset, the peak hold circuit 12 successively holds the maximum output value of the double wave rectifier circuit 9 and outputs it.

Next, in the control circuit 3, the arithmetic circuit 13 outputs the output e of the peak hold circuit 12 (see Fig. 3 e).
and the reference voltage E (e−E), and the integrating circuit 14 integrates the output of the subtracting circuit 13.

On the other hand, in the attenuation discrimination device 6, the comparator 15
compares the output a of the BPF8 with the ground potential, and becomes "1" only when the output a is a negative potential (Fig. 3c)
reference). Then, when the output c of the comparator 15 changes from "1" to "0", the inverters 16,1
7 output is “1”, analog switch 20, 24
is open, analog switches 21 and 23 are closed,
Since the peak hold circuit 18 is reset,
The peak hold circuit 18 holds the maximum output value of the double-wave rectifier circuit 9, while the peak hold circuit 19 outputs the maximum output value f of the double-wave rectifier circuit 9 half a cycle before, which has been held until then. Further, when the output c of the comparator 15 changes from "0" to "1", the peak hold circuit 18 outputs the maximum output value f of the circuit 9 held half a period before, and the peak hold circuit 18 holds the maximum output value of circuit 9. The differential amplifier circuit 22 receives the output e of the peak hold circuit 12 and the peak hold circuit 18,
The comparator 25 amplifies the difference between the output f of the differential amplifier circuit 22 and the reference voltage E, that is, the difference (attenuation degree) between the maximum output value of the double-wave rectifier circuit 9 at the current time and half a period before. Compare. If continuous roughness occurs in the engine 1a, the output (attenuation degree) of the differential amplifier circuit 22 is smaller than the reference voltage E, the output of the comparator 25 is "1", and the analog switch 26 is opened. , in the control circuit 3, the integration circuit 14 integrates the output of the subtraction circuit 13, and outputs it as a roughness control signal from the output terminal 3a. Further, when a single roughness occurs in the engine 1a, the output of the differential amplifier circuit 22 becomes higher than the reference voltage E, and the output of the comparator 25 becomes "0".
Since the analog switch 26 is closed, the input from the subtraction circuit 13 to the integration circuit 14 is cut off, and no roughness control signal for the one-shot roughness is output to the output terminal 3a of the control circuit 3.

Further, FIG. 4 shows a second embodiment of the present invention,
1, 4, 5, 6, and 7 are the above-mentioned vibration detector, roughness control device, actuator, damping discrimination device, and correction device, and 27 is a parameter indicating the operating state of the engine, such as engine rotation speed, intake negative pressure, etc. 28 is a control circuit that receives the output of the operating state detector 27 and generates a reference operating state control signal; 29 converts the reference operating state control signal into a roughness control signal from the roughness control device 4; A correction circuit 30 that corrects accordingly and applies it to the actuator 5 is constituted by the above-mentioned components 5, 27 to 29, and is a various operating state control device that controls the operating state of the engine.

In this way, the engine vibration detection device may be one that performs correction control on the operating state control device, and in this embodiment, the same operation and effects as in the above embodiment can be obtained.

As described above, according to the engine vibration detection device according to the present invention, it is possible to determine whether or not the engine vibration is one-off roughness due to a misfire based on the magnitude of the damping degree of the engine vibration, and to determine whether the engine vibration is one-off roughness due to a misfire. Since the roughness control is stopped when it is determined that this is the case, it is possible to prevent the roughness control from becoming overcontrolled due to the occurrence of one-off roughness, and there is an effect that optimum roughness control can be performed at all times.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an engine vibration detection device according to an embodiment of the present invention, FIG. 2 is a detailed circuit diagram of the device, and FIGS. 3 a to 3 are BPF8 of the device,
double wave rectifier circuit 9, comparator 15, inverter 11,
The output waveform diagram of the peak hold circuit 12 and the peak hold circuits 18 and 19, and FIG. 4 is a configuration diagram of another embodiment of the present invention. 1... Vibration detector, 4... Roughness control device,
5...actuator (various operating state control devices),
6... Attenuation discrimination device, 7... Correction device, 30...
Various operating state control devices.

Claims (1)

[Claims] 1 a vibration detector that detects engine vibration; a roughness control device that detects engine roughness from the output of the vibration detector and controls various operating state control devices of the engine in a direction to suppress the roughness; and the vibration detector. a damping determination device that receives an output from the damping determination device and determines whether engine vibration is attenuated to a degree of attenuation equal to or higher than a predetermined value; and a correction device that receives a determination signal from the damping determination device and stops control by the roughness control device. An engine vibration detection device characterized by comprising: