JP2523233B2 - Secondary voltage waveform detector for gasoline engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary voltage waveform detecting device for dividing and detecting a secondary voltage waveform generated in a secondary circuit of an ignition circuit in a gasoline engine.

[0002]

2. Description of the Related Art In order to purify exhaust gas of an automobile engine and to improve fuel efficiency, there is a demand for a device capable of detecting an ignition state for each cylinder of an engine and preventing a misfire in all cylinders. Further, as a misfire detection device, conventionally, a method of making a hole in a cylinder block and mounting a combustion light sensor, mounting a pressure sensor on a mounting seat of a spark plug, and measuring an ionic current of an ignition circuit are known.

[0003]

In the conventional method, the mounting is troublesome, and when it is mounted on all the cylinders of all vehicles, the mounting cost increases and maintenance is troublesome. An object of the present invention is to provide a secondary voltage waveform detection device capable of accurately detecting the waveform of the secondary voltage applied to all the spark plugs mounted on each cylinder with a simple structure and easy mounting.

[0004]

A secondary voltage waveform detecting device of the present invention is mounted near a secondary circuit of an ignition circuit,
A sensor having a predetermined capacitance with the secondary circuit,
And a voltage divider composed of a capacitor connected to the sensor, a secondary voltage detection circuit for detecting a secondary voltage waveform divided by the voltage divider, a secondary voltage waveform detected by the detection circuit is analyzed, and a gasoline In a secondary voltage waveform detection device for a gasoline engine, which comprises a discrimination circuit for outputting to a control means of the engine, an electrode plate to which a lead wire is connected to an insulating body having a groove for fitting a high voltage cord and a recess for fitting a base plate. Is arranged in the vicinity of the groove forming portion to form a sensor, and the circuit board of the capacitor, the detection circuit and the determination circuit is fitted and fixed in the recess.

[0005]

According to the present invention, since a substantially uniform capacitance can be formed in the secondary circuit for supplying the secondary voltage to the spark plugs mounted on all the cylinders with one sensor, it is possible to form each cylinder. The secondary voltage can be detected without variation.
In addition, by integrating the sensor and the circuit board, the output line of the sensor can be placed inside the main body, and the wiring can be simplified, so it is easy to install, and matching, adjustment, and maintenance of the sensor and circuit are possible. Can be done easily.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a secondary voltage waveform detecting device 1 according to the present invention.
00 is shown. Reference numeral 1 denotes a resin-made rectangular parallelepiped main body, in which one surface 11 is provided with U-shaped grooves 12 in the same number as the number of cylinders of a gasoline engine in parallel, and the other surface 13 is provided with a rectangular recess 14 so that a base is installed. It is room 15. A power supply and output outlet 16 is provided on the side surface of the main body 1.

As shown in FIG. 2, the groove 12 of the main body 1 is provided with grooves 21 corresponding to the grooves 12 in parallel, and a lead plate 22 is soldered to the corners to form a metal plate-like metal plate. 20
The electrode plate made of is embedded. The metal plate 20 is embedded at the time of injection molding of the main body 1 to form the secondary voltage sensor 2. In addition, the lead wire 22
In addition to being connected to the circuit board 3, a substrate 3 in which a capacitor, a voltage dividing detection circuit, a determination circuit for analyzing the divided secondary voltage waveform, and the like are installed is accommodated and fixed by a filled resin 4. The shape of the grooves of the metal plate 20 may be polygonal, oval, or the like, and a flat plate without grooves may be used as the electrode plate.

As shown in FIG. 3, in the groove 12 of the main body 1, a high pressure cord (high tension cord) 5 which constitutes a secondary circuit of an ignition circuit and which connects the distributor D of the engine E and the spark plug P is provided. Fitted, body 1
It is fixed by a cover plate 17 fastened to one surface 11. In this state, the secondary voltage detection device 100 is mounted on the engine E as shown in FIG. 4, and the plug 1 in which the lead wires to the engine control device and the power supply are connected to the outlet 16
8 is inserted.

FIG. 5 shows an ignition circuit of a gasoline engine equipped with the secondary voltage detecting device of the present invention. The ignition circuit is
A distributor D, an ignition coil T, and a spark plug P are provided. The secondary voltage sensor 2 constitutes a secondary voltage divider 6 with a capacitor C connected between the sensor 2 and ground, and the divider 6 is connected to a secondary voltage waveform detection circuit 7 and a detection circuit. 7 is connected to a discrimination circuit 8 such as a microcomputer.

The ignition coil T has a primary circuit L1 connected to the vehicle-mounted power source V and the signal generator SG, and a secondary circuit L2 connected to the distributor D and the spark plug P. The sensor 2 holds a capacitance of 1 pF with the high tension cord 5 of each cylinder. The capacitor C is connected between the sensor 2 and the ground and has a capacitance of 3000 pF. In addition, in this embodiment, a resistor R of 3 megaΩ is connected in parallel with the capacitor C,
The discharge circuit of the capacitor C is used. The voltage divider 6 divides the secondary voltage generated in the secondary circuit L2 to 1/3000.
As a result, the time constant of the RC circuit can be set to about 9 milliseconds, and a relatively gradual change in secondary voltage can be measured.

The detection circuit 7 analyzes the divided voltage waveform of the voltage divider 6 and compares the characteristics of the divided voltage waveform with data obtained in advance by experiments or calculations. The partial pressure waveform of the sensor 2 and the capacitor C is a waveform obtained by dividing the voltage waveform of the spark plug almost as it is, and when the fuel-air mixture in the cylinder of the engine is ignited, spark discharge occurs, but the ignition occurs. If not performed, the secondary voltage waveform of the spark plug P is different from that in the case where a sparking mistake occurs due to smoldering of the spark plug, deterioration of the performance of the ignition coil, voltage decrease of the battery, or the like. By analyzing the secondary voltage waveform, it is possible to determine the state of the gasoline engine, such as a misfire, misfire, or normal ignition.

The discriminating circuit 8 receives the output of the detecting circuit 7, compares the characteristics of the divided voltage waveform with data obtained in advance by experiment or calculation, and outputs a predetermined output to the main computer for controlling the gasoline engine. Alternatively, a control signal is output to the control means for controlling the fuel injection amount and the injection timing.

In the above embodiment, the metal plate 20 in the form of a ladle plate is embedded in the main body 1 as the electrode plate.
May be fixed to the bottom of the substrate installation chamber 15 or an electrode plate may be formed by forming a conductive layer on the back surface of the substrate 3 by printing or the like, and the electrode 2 may be embedded in the lid 17 to form the sensor 2. .

[Brief description of drawings]

FIG. 1 is an assembled perspective view of a secondary voltage detection device of the present invention.

FIG. 2 is a perspective view of a metal plate and a circuit board.

FIG. 3 is a perspective view of a secondary voltage detection device according to the present invention.

FIG. 4 is a diagram showing how the secondary voltage detection device of the present invention is mounted on an engine.

FIG. 5 is an ignition circuit diagram of a gasoline engine using the secondary voltage detection device of the present invention.

[Explanation of symbols]

 100 Secondary voltage detector 1 Main body 2 Secondary voltage sensor 3 Circuit board 4 Resin 5 High voltage cord 6 Voltage divider 7 Secondary voltage waveform detection circuit 8 Discrimination circuit 12 Groove 14 Recess 20 Metal plate

Claims (1)

(57) [Claims] 1. A voltage divider, which is mounted in the vicinity of a secondary circuit of an ignition circuit and has a predetermined capacitance between the secondary circuit and the secondary circuit, and a voltage divider composed of a capacitor connected to the sensor, Gasoline engine including a secondary voltage detection circuit for detecting a secondary voltage waveform divided by a voltage divider, and a determination circuit for analyzing the secondary voltage waveform detected by the detection circuit and outputting it to the control means of the gasoline engine In the secondary voltage waveform detection device, the sensor plate is formed by disposing the electrode plate to which the lead wire is connected in the vicinity of the groove forming portion in the main body made of an insulating material having the high voltage cord fitting groove and the base fitting recess. At the same time, the secondary voltage waveform detecting device for a gasoline engine is characterized in that the circuit board of the capacitor, the detection circuit and the determination circuit is fitted and fixed in the recess.