JP2657004B2 - Internal combustion engine combustion detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion detecting device for an internal combustion engine, and more particularly to a combustion detecting device for an internal combustion engine capable of preventing malfunction due to noise.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing a conventional combustion detecting device for an internal combustion engine. In the figure, 1 is a power transistor that is turned on and off by an ignition signal, 2 is an ignition coil in which the power transistor 1 is connected to the primary side, 3 is a distributor connected to the secondary side of the ignition coil, and 4 is a distributor A plurality of ignition plugs respectively connected to 3; a plurality of ion current detection diodes respectively connected to the ignition plug 4;
Reference numeral 6 denotes an ion current detection device for detecting an ion current, 7 denotes a comparator provided in the ion current detection device 6 and compares the ion current detection signal with a reference value, and 8 denotes an output terminal.

Next, the operation of the conventional combustion detecting device for an internal combustion engine shown in FIG. 3 will be described with reference to FIG.
Now, when an ignition signal S1 as shown in FIG. 4A is applied to the base of the power transistor 1, the power transistor 1 is turned on, and at the time when the power transistor 1 is turned off, the secondary side of the ignition coil 2 is turned on. A high voltage signal S2 as shown in FIG. 4B is generated. The high voltage signal S2 is supplied to the ignition plug 4 of each cylinder via the power distributor 3 and ignites it. When the mixed gas in the cylinder burns due to this ignition, an ionic current is generated, and cations of the ionic current are detected through the diode 5 as an ionic current detection signal S3 as shown in FIG. The ion current detection output signal S4 as shown in FIG. When the ion current detection output signal S4 is at a high level, it is determined that combustion has occurred, and when it is at a low level, misfire is determined.

[0004]

Since the conventional combustion detecting device for an internal combustion engine is constructed as described above, various noises are superimposed on the signal S4 when mounted on an actual vehicle. "H" due to noise is included in the signal S4.
There is a problem that a signal is output and there is a risk that it is determined that combustion has been performed normally. The present invention has been made to solve the above problems,
It is an object of the present invention to obtain a combustion detection device for an internal combustion engine that can reliably detect misfire by removing various noises generated when the vehicle is mounted on an actual vehicle.

[0005]

Means for Solving the Problems] combustion detecting apparatus for an internal combustion engine according to the present invention, a voltage is applied to the spark plug of the cylinder of the internal combustion engine, and the ion current detecting means that gives detects the ion current due to the combustion, the ion Ions detected by current detection means
The current level is shifted by a predetermined amount and compared with a predetermined reference value.
A comparison means, a filter means for passing only a signal having a width equal to or longer than a predetermined time out of an output of the comparison means ,
Waveform shaping means for shaping the waveform of the output of the filter means .

[0006]

In the present invention, a negative ion current due to combustion is detected, the negative ion current detection signal is shifted by a predetermined bias voltage, and the shifted negative ion current detection signal is converted to a bias voltage. An ion current detection output signal is obtained by comparing with a first reference value shifted by a predetermined amount, filtering, and further comparing with a second reference value.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing one embodiment of the present invention.
1 to 5, 7, and 8 are the same as described above. 6A is an ion current detection device. In this embodiment, the ignition coil 2
Connect the following side end (the negative electrode) in the distributor 5 connects the other end (the positive electrode <br/> end) of the ion current detector 6A. Ion current
An ion current detecting diode 5 as a detecting means is incorporated in the power distributor 3. In addition, a positive polarity battery is used for the ion current detection battery unit in the ion current detection device 6A. That is, in the present embodiment, anions and free electrons in the ion current are detected. The ion current detection device 6A is provided on the input side and shifts the detected ion current detection signal by a predetermined bias voltage. The bias circuit 9 is provided on the output side of the bias circuit 9 and shifts the ion current detection signal. a comparator 7 for comparing the first reference value by a predetermined amount shifted from the bias voltage provided on the output side of the comparator 7, as a filter means for filtering the output
And a comparator 11 provided on the output side of the low-pass filter 10 for comparing the filtered output with a second reference value and masking the filtered output for a predetermined time.
1. An inverting circuit 1 provided on the output side of the inverter 1 for inverting its output
2 Note that the bias circuit 9 and the comparator 7 are a comparator.
The comparator 11 and the inverting circuit 12 are configured as waveform shaping means.
Is configured.

Next, the operation of the embodiment of the present invention shown in FIG. 1 will be described with reference to FIG. Now, when an ignition signal is applied to the base of the power transistor 1, the power transistor 1 is turned on, and a high voltage signal is generated on the secondary side of the ignition coil 2 when the power transistor 1 is turned off. This high voltage signal is supplied to the ignition plug 4 of each cylinder via the distributor 3 and ignites it. When the mixed gas in the cylinder burns due to the ignition, an ionic current is generated, and anions and free electrons of the ionic current pass through the diode 5 and are detected as an ionic current detection signal S1 as shown in FIG. Is done. The ion detection signal S1 is shifted by a predetermined bias voltage by the bias circuit 9 to become a signal S2 as shown in FIG.
The signal S3 is supplied to the comparator 7 and compared with the first reference value, and a signal S3 as shown in FIG. This signal S3 is passed through a low-pass filter 10 to
Next signal S4 such as shown in (d), is further compared with a second reference value is supplied to the comparator 11, the predetermined time mask of
After that, the signal S5 as shown in FIG.
Is obtained. This signal S5 is inverted by the inverting circuit 12, and
As a result, an ion current detection output signal S6 as shown in FIG. When the ion current detection output signal S6 is at a high level, it is determined that combustion has occurred, and when it is at a low level, misfire has been determined. The signal S6 thus obtained outputs an "H" level signal at the time of combustion, and outputs an "L" level signal at the time of misfire, so that noise and ion current from the final output waveform of the ion current detection device are output. It is not necessary to determine the detection signal, and the misfire can be reliably detected.

[0009]

According to the present invention as described above, according to the present invention, an ion current detecting means that a voltage is applied to the spark plug of the cylinder of the internal combustion engine, issuing detects the ion current due to the combustion, the ion current
The level of the ion current detected by the detection means is shifted by a predetermined amount.
Comparing means for comparing the data with a predetermined reference value;
Filter means for passing only signals having a width of a predetermined time or more of the outputs, integer output of the filter means waveform
With the provision of the waveform shaping means , it is possible to obtain an internal combustion engine combustion detection device capable of removing various noises generated when the vehicle is mounted on an actual vehicle and reliably performing misfire detection.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is a waveform diagram for explaining the operation of FIG. 1;

FIG. 3 is a configuration diagram showing a conventional combustion detection device for an internal combustion engine.

FIG. 4 is a waveform chart for explaining the operation of FIG. 3;

[Explanation of symbols]

 Reference Signs List 4 spark plug 5 ion current detecting diode 6A ion current detecting device 7, 11 comparator 9 bias circuit 10 low-pass filter 12 inverting circuit

Claims (1)

(57) [Claims] 1. A voltage is applied to the spark plug of the cylinder of the internal combustion engine, and the ion current detecting means that gives detects the ion current due to the combustion, the level of the ion current detected by the ion current detecting means
Means for shifting by a predetermined amount and comparing with a predetermined reference value
When the combustion of the internal combustion engine, characterized by comprising filter means for passing only a signal having a width of a predetermined time or more among the outputs of the comparison means, and a waveform shaping means for shaping the waveform of the output of said filter means Detection device.