JPH08284790A - Ion current detector for internal combustion engine - Google Patents

Abstract

PURPOSE: To detect a combined detection voltage with only ion current separated by combining an output of a switching means which synchronizes for switching operation during turning off switching means. CONSTITUTION: When transistors 11, 21, 31, 41 are turned off for respectively cylinders by ignition signals 11a, 21a, 31a, 41a, the charging voltage of capacitors 14, 24, 34, 44 is applied to ignition plugs 12, 22, 32, 42, thus generating output voltages at detection terminals 17, 27, 37, 47. The voltage, which is negative, is inputted into an analog switch 200 through reversing amplifiers 18, 28, 38, 48. Switching signals 201, 202 of the analog switch 200 are formed by synchronizing with falling of ignition signals 11a-41a from a control circuit 500. An output 300 of the analog switch 200 is outputted by a combination of the switching signals 201, 202, so it is possible to obtain only voltage by ion current of output voltage at the detecting terminals 17, 27, 37, 47 of respective cylinders.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-cylinder internal combustion engine,
In particular, the present invention relates to an ion current detecting device for an internal combustion engine, which is suitable for detecting an ion current during combustion.

[0002]

2. Description of the Related Art Detection of ion current in a single cylinder is disclosed in Japanese Patent Laid-Open No. 4-191465, and for multiple cylinders, Japanese Patent Laid-Open No. 5-260.
The method of synthesis is proposed in Japanese Patent Publication No. 94. However, JP-A-5-26094 does not consider the processing of the detection voltage other than the ion current generated in the detection method of JP-A-4-191465, and the combined detection voltage is other than the ion current of each cylinder. There is a problem that includes the voltage of. Furthermore, when the ion current continues until the ignition of the next cylinder, the problem that the detection voltage due to the ion current of the next cylinder overlaps has not been solved.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to separate a combined detection voltage by an ion current for detection, and to prevent the detection voltage due to the ion current of the next cylinder from overlapping. .

[0004]

In a multi-cylinder internal combustion engine that has a plurality of ignition coils, a switch means on the primary winding of the ignition coils, and an ignition plug on the secondary winding to cause combustion in a cylinder, each cylinder Means for applying a voltage to each of the spark plugs to detect a current caused by ions during combustion, a switching means for sequentially outputting one input using the output of the detecting means as an input, and an output of the switching means being combined. connection,
The misfire detection device for an internal combustion engine, wherein the switching means performs a switching operation in synchronism with the switching means being turned off.

[0005]

The ionic current starts flowing after the switch means is turned off and is output by the detection means. Since the switching means transfers the input from the turning off of the switching means to the output, when the outputs of the switching means are combined, an unnecessary waveform when the switching means is turned on is not transferred.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention and shows a four-cylinder internal combustion engine. Ignition coil 10, 20, 3
0, 40 primary windings 10a, 20a, 30a, 40a
One is the battery 100, the other is the transistor 11,
21, 31, 41 connected to the ignition signals 11a, 21
The a, 31a, and 41a are controlled by the control device 500. One of the secondary windings 10b, 20b, 30b, 40b has a spark plug 12, 22, 32, 42, and the other has a constant voltage diode 13, 23, 33, 43 and a capacitor 14, 24, 3.
4, 44 are connected in series with the diodes 15, 25, 35, 45 and the detection resistors 16, 26, 36, 46 in parallel and connected to the ground. The detection voltage 17, 27, 37, 47 is connected to the input of the analog switch 200 via the inverting amplifier 18, 28, 38, 48. The output 300 of the analog switch 200 synthesizes four signals and integrates the integration circuit 40.
0 as an input and an integrated output 401 as an A / D of the control device 500.
Connected to the converter. Switching signals 201 and 202 of the analog switch 200 and a reset signal 40 of the integrating circuit 400
2 is controlled by the control device 500.

By the way, FIG. 2 shows the ignition signal 11 for one cylinder.
The detection operation of the ion current corresponding to a, FIG. 3 is the waveform of the detection voltage. First, regarding ignition, when the transistor 11 is turned off at time t2, the secondary winding 10 of the ignition coil 10 is turned on.
A positive high voltage is generated on the lower side of b, discharge occurs in the spark plug 12, and a current flows through the path indicated by the dotted line. The discharge continues until time t3, during which the capacitor 14 is charged with the voltage in the direction shown in the figure, which is limited by the constant voltage diode 13. At this time, as the detection voltage 17, the forward voltage drop of the diode 15 whose upward direction is positive is output. When combustion occurs, the charging voltage of the capacitor 14 in the illustrated direction is applied to the spark plug 12
Therefore, the ion current flows in the path indicated by the solid line, and the detection voltage 17 of 17b is obtained. By the way, there is a stray capacitance 600 between the spark plug and the high-voltage cord connected to the spark plug and the ground. Therefore, at time t1, the transistor 11 is turned on to turn on the secondary winding 11 of the ignition coil 10.
When the voltage on the upper side is generated in b, the current indicated by the alternate long and short dash line flows through the path of the forward direction of the stray capacitance 600 → the constant voltage diode 13, so that the voltage waveform of 17a is output to the terminal 17. This voltage 17a is the voltage 17 due to the ion current.
It should be distinguished from b.

The operation of FIG. 1 will be described with reference to FIG. The operation of FIG. 3 is repeated for each cylinder by the ignition signals 11a, 21a, 31a, 41a, and the detection terminals 17, 27, 37, 4 are detected.
The output voltage is obtained at 7. Since this voltage is a negative voltage, it is input to the analog switch 200 via the inverting amplifiers 18, 28, 38 and 48. Analog switch 20
The switching signals 201 and 202 of 0 are generated from the control circuit 500 in synchronization with the falling edges of the ignition signals 11a to 41a. From this, the output 300 of the analog switch 200
Is a combination of switching signals 201 and 202 10,01,1
Since it is output at 1,00, the detection terminals 17, 2 of each cylinder
Among the output voltages 7, 37, 47 are voltages 17a, 27a,
37a and 47a are removed and the voltage 17 due to the ion current
Only b, 27b, 37b, 47b are obtained. The output 300 is integrated by the integrator 400, and the integrated voltage 401 is input to the A / D converter of the control device 500. Control device 500
Signal 402 from integrator 400 provides the integration period.

According to one embodiment of the present invention, the ignition coil 1
When a current is applied to the primary windings 10a to 10b of 0, 20, 30, 40, the ion current detection terminals 17, 27, 3
Detection voltages other than the ion current detected at 7, 47 can be removed.

FIG. 5 is a diagram showing another embodiment of the present invention. When the output voltage of the ion current detection terminals 17, 27, 37, 47 overlaps with the ignition operation of the next cylinder, the detection voltage is cut midway in FIG. Therefore, the analog switch 200 shown in FIG. 3 is divided into 210 and 220, and the detection terminals 17, 27, 37, 47 are connected to the analog switch 210 by the ion current outputs 17 and 37 in which the cylinders in the explosion process and the exhaust process are paired. Connect 27 and 47 to 220. Then, the number of integrating circuits is set to 410 and 420, and the control device 500
There are also two A / D converted signals to 411 and 421.

The operation of FIG. 5 will be described with reference to FIG. The switching of the analog switches 210 and 220 is performed by inputting the ignition signal of the cylinder input thereto, that is, the analog switch 210 outputs the signal 21 synchronized with the fall of the ignition signals 11a and 31a.
1, the analog switch 220 is the ignition signal 21a and 41a
The signal 221 is synchronized with the falling edge of. When the switching signal 211 is 1, the detection voltage of the terminal 17 is obtained, when it is 0, the detection voltage of the terminal 37 is obtained as the output voltage 310, when the switching signal 221 is 1, the detection voltage of the terminal 27 is obtained, and when it is 0, the terminal 4 is obtained.
The detected voltage of 7 is obtained as the output voltage 320. Switching signal 2
11 and 221 are controlled by the control device 500. The output voltages 310 and 320 are integrated by integrating circuits 410 and 420, respectively, and the outputs 411 and 421 are read by the A / D converter of the controller 500. Integrating circuits 410 and 420
Of the signals 211 and 22 from the control device 500.
Controlled by 1.

According to this embodiment, in addition to the effect obtained in FIG. 3, the entire ion current can be detected even when the ion current continues to flow until the ignition operation of the next cylinder.

[0013]

According to the present invention, the ion current can be reliably detected.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of an ion current detection device according to the present invention.

FIG. 2 is an explanatory diagram of a basic principle of the present invention.

FIG. 3 is an explanatory diagram of a basic principle of the present invention.

FIG. 4 is a timing chart showing the operation of the embodiment of FIG.

FIG. 5 is a circuit diagram showing another embodiment of the ion current detector according to the present invention.

FIG. 6 is a timing chart showing the operation of the embodiment shown in FIG.

[Explanation of symbols]

10, 20, 30, 40 ... Ignition coil 11, 21, 3
1, 41 ... Transistor, 12, 22, 32, 42 ... Spark plug, 13, 23, 33, 43 ... Constant voltage diode, 14, 24, 34, 44 ... Capacitor, 15, 2
5, 35, 45 ... Diodes, 16, 26, 36, 46
... resistors, 18, 28, 38, 48 ... inverting amplifier, 20
0, 210, 220 ... Analog switch, 400, 41
0, 420 ... Integrating circuit, 500 ... Control device.

Claims (3)

[Claims] 1. A multi-cylinder internal combustion engine having a plurality of ignition coils, a switch means on a primary winding of the ignition coil, and an ignition plug on a secondary winding to cause combustion in a cylinder, and the ignition for each cylinder. Means for applying a voltage to the plug to detect a current due to ions during combustion, switching means for switching the transmission to the output by using the output of the detecting means as an input, and connecting so as to combine the output of the switching means, An ionic current detection device for an internal combustion engine, wherein the switching means performs the switching operation in synchronization with the switching means being turned off. 2. The misfire detection device for an internal combustion engine according to claim 1, wherein the switching means inputs an analog value and outputs the analog value. 3. A multi-cylinder internal combustion engine having a plurality of ignition coils, a switch means on a primary winding of the ignition coil, and an ignition plug on a secondary winding, to generate combustion in a cylinder, wherein the ignition is performed for each cylinder. A means for applying a voltage to the plug to detect a current caused by ions during combustion; a switching means for switching the transmission to the output by using the output of the detecting means as an input, with the cylinder of the explosion process and the exhaust process of the internal combustion engine as a pair, An ionic current detection / detection device for an internal combustion engine, wherein the switching means is connected so as to combine the outputs of the switching means, and the switching means performs a switching operation in synchronization with the switching means being off.