JPS6217115B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a voltage detection probe, and particularly to an ignition coil, a coil cord, a distributor, a plug cord, and a spark plug suitable for detecting a secondary voltage in an ignition circuit of an internal combustion engine for an automobile. The present invention relates to a voltage detection probe for directly detecting an electrical signal from an ignition circuit of an internal combustion engine having components such as the above.

Generally, the ignition circuit based on the high voltage ignition method applied to internal combustion engines such as automobiles has an ignition coil,
It consists of a coil cord, distributor, plug cord, and spark plug, and the secondary voltage of several tens of kilovolts generated from the secondary output end of the ignition coil when the engine is running.
It is supplied to a distributor through a coil cord, distributed to each cylinder of the engine by the rotation of the distributor, and supplied to the spark plug of each cylinder through a plug cord to generate a spark at the spark plug. . The spark from the ignition plug ignites and burns the combustible gas inside the engine and cylinder, thereby operating the engine. Therefore, when the engine is running, it is necessary to always supply an appropriate secondary voltage to the ignition plug in order to maintain the engine in good operating condition.

For example, if the secondary voltage output from the secondary output terminal of the ignition coil decreases due to a failure or deterioration in performance of the ignition coil, which is a component of the ignition circuit, it becomes impossible to supply sufficient voltage to the ignition plug. This may even cause the engine to misfire or become inoperable. or,
If parts of the ignition coil, coil cord, distributor, plug cord, etc. are dirty or cracked, the secondary voltage output from the ignition coil may
These defects leak to the engine body and ground, making it impossible to supply sufficient voltage to the spark plug. Furthermore, dirt on the spark plug's electrode, smoldering or incorrect electrode gap, and the mixture of flammable gases in the engine and cylinder all greatly affect the secondary voltage supplied to the spark plug. This causes the inability to generate enough spark, resulting in the engine misfiring or the like.
Therefore, timely detection of the secondary voltage output from the ignition coil in the engine's ignition circuit and understanding whether the secondary voltage value is appropriate is important for safety management and performance maintenance of automobiles, etc. It is.

Conventionally, the number of outputs from the ignition coil during performance tests or inspection and maintenance of engines etc.
There is no effective means to easily, accurately, and safely detect a high-voltage secondary voltage of 10KV. For example, it is extremely difficult to install a detection means called a large partial pressure probe in the ignition circuit of the engine, and the workability is poor, and furthermore, it is difficult to install it near the rotating engine. The danger is also great. In addition, since the generally used detection means using the induction coil method is AC coupled, it cannot accurately detect the secondary voltage that includes the DC component, and furthermore, it cannot accurately detect the secondary voltage that includes the DC component. Conventional means have several drawbacks, such as the fact that accuracy is greatly influenced by Particularly in engine inspection and maintenance, it is required to detect the secondary voltage safely and with high accuracy with simple operation.

The present invention has been made to eliminate the above-mentioned conventional drawbacks, and is capable of accurately and safely detecting the secondary voltage in the ignition circuit of an engine, etc. over a wide range from its DC component to its high frequency component with simple operation. The purpose of the present invention is to provide a voltage detection probe capable of

The present invention provides a voltage detection probe for directly detecting an electrical signal from an ignition circuit of an internal combustion engine whose components include an ignition coil, a coil cord, a distributor, a plug cord, a spark plug, etc. a conductor inserted between the elements and provided at both ends with fitting parts capable of electrically contacting the connection parts between the respective components; a first voltage dividing resistor having one end connected to the conductor; a second voltage dividing resistor and a capacitor whose one end is collectively connected to the first collective connection point of the other end of the first voltage dividing resistor and whose other end is collectively connected to the second collective connection point; a cylindrical capacitor plate disposed on the circumference of the first voltage dividing resistor that is connected to the collective connection point to form a capacitor, and a signal line connected to the first collective connection point; The above object is achieved by comprising a ground wire connected to the second collective connection point, and a case made of an insulating member that houses the first and second voltage dividing resistors, capacitor plates, and capacitors. has been achieved.

Further, a protection diode is connected between the first collective connection point and the second collective connection point to prevent overvoltage from being applied to an external processing device connected to the signal line. be.

The present invention will be described in detail below based on preferred embodiments shown in the drawings.

In the example of the ignition circuit for an engine, etc. shown in FIG. By the operation of T (referred to as an igniter), a primary voltage of several hundred volts is generated on the primary side _IG1 of the ignition coil IG. The primary voltage is boosted to several tens of KV by the boost function of the ignition coil IG, and is output as a secondary voltage to the secondary output terminal IG ₂ of the ignition coil IG, and is usually distributed via the coil cord IC. RO
is supplied to each cylinder by the rotation of the distributor RO, and the plug code PC of each cylinder is
The fuel is supplied to the spark plug PL of each cylinder via.

The voltage detection probe P according to the present invention is used with one end connected to the secondary output terminal _IG2 of the ignition coil IG, and the other end connected to the terminal of the coil cord IC. This connection method detects the secondary voltage output from the ignition coil IG by simply removing the coil cord IC from the secondary output terminal IG ₂ of the ignition coil IG and inserting the probe P according to the present invention between the two. It is possible to achieve extremely good workability. Further, the output of the probe P is derived from the cable C and processed as a secondary voltage value by a processing circuit (not shown). Furthermore, the ground wire E of the probe P is connected to the engine and ground by suitable clip means.

The internal circuit of the probe P is formed from a voltage dividing circuit shown in Fig. 2, and includes a terminal 1 and a coil cord IC connected to the secondary output terminal _IG2 of the ignition coil IG.
A conductor 2 is connected between the terminals 3 connected to the ends, and a high secondary voltage can be passed therethrough. conductor 2
The secondary voltage applied to the conductor 2 is applied to the conductor 2 from the middle of the
and is led to the ground wire E. Further, a detection signal is led by a signal line 9 from the connection point (first collective connection point) between the voltage dividing resistors 4 and 5 and the compensation capacitors 6 and 7, and one of the signal line 9 and the ground line E is It is connected to the processing circuit by cable C. Further, a protective diode 8 is connected between the ground line E and the connection point between the voltage dividing resistors 4 and 5 and the compensation capacitors 6 and 7.

According to the above connection configuration, due to the voltage dividing effect of the voltage dividing resistors 4 and 5, mainly the DC component of the secondary voltage of several tens of KV applied to the connection point between the voltage dividing resistor 4 and the conductor 2 is reduced to a low voltage. Performs the action of converting into a signal. or,
The compensation capacitors 6 and 7 function to accurately compensate for the voltage division effect of the high frequency component of the secondary voltage.
Furthermore, the protection diode 8 is connected to the voltage dividing resistors 4 and 5 when the voltage dividing effect is impaired due to aged deterioration or failure of the voltage dividing resistor 4 and the compensation capacitor 6.
Even if an excessive secondary voltage is applied to the connection point with the signal line 9 and the signal line 9, the protection diode 8 acts to bypass the ground line E, and the excessive voltage is applied from the signal line 9 to the processing circuit. It plays an important role in the safety of the processing circuit, so that it is not damaged.

As described above, the voltage detection probe P according to the present invention
Due to the voltage dividing effect of the voltage dividing resistors 4 and 5 and the compensation capacitors 6 and 7, the high voltage secondary voltage containing a DC component is converted to the secondary voltage with extremely wide frequency characteristics from DC to high frequency. can be converted into low voltage signals with high precision. Furthermore, the insertion of the protective diode 8 is extremely effective as a safety measure for the voltage detection probe P.

Furthermore, by forming the compensation capacitor 6 as a cylindrical capacitance compensating plate on the circumference of the voltage dividing resistor 4, the compensation capacitor 6 is formed as a cylindrical capacitance compensating plate, which is likely to occur when an engine ground or the like is brought close to the voltage dividing resistor 4. The influence of stray capacitance and the like can be extremely reduced, and the partial voltage characteristics of the probe P can be compensated for. Furthermore, the protective diode 8 is a constant voltage diode, an avalanche diode, or a general rectifier diode, and can be arbitrarily selected depending on its connection direction, and the operating voltage of the protective diode is also the same as that of the secondary voltage. It is arbitrarily selected depending on the measurement range.

Next, the specific structure of the voltage probe P according to the present invention will be explained with reference to FIG.

As shown in the figure, the probe P has a structure in which each electric element is fixed inside an insulating case 21, and the insulating case 21 is made of an electrically insulating material such as Diuracon or Bakelite.

A terminal 1 made of a metal material is fixed to an insulating case 10 such as a diyuracon with a metal screw 12, and the metal screw 12 is fixed to be electrically conductive to a metal fitting 13 connected to a conductor 2. . Terminal 1
has a spring property that makes it easy to be inserted and fitted into the secondary output end _IG2 of the ignition coil IG. Further, the hole 11 of the insulating case 10 serves as a protective cover for electrically shielding from the outside when the terminal 1 is inserted and fitted into the secondary output terminal _IG2 of the ignition coil IG. The conductor 2 connected to the metal fitting 13 is formed from a high voltage insulated cable 14, and the outer periphery of the insulated cable 14 is surrounded by an insulating coating 15 such as a silicon tube to further improve the insulation properties of the conductor 2. , increasing safety.

The other end of the conductor 2 is connected to a terminal 3 made of a metal material.
The terminal 3 is housed in an insulating case 16 such as a diyuracon. The upper part of the insulating case 16 is provided with a hole 17 into which the coil cord IC is inserted and fitted, and a hook hole 1 for hanging the probe P itself at an appropriate location when not in use.
8 is provided.

Next, the insulating case 21 is integrally molded or assembled by welding with the insulating case 16 that houses the terminal 3, and the voltage dividing resistors 4 and 5, the compensation capacitors 6 and 7, and the protective diode 8 are housed inside the insulating case 22. After the electric element is assembled inside the case 22,
Molded and fixed with insulating filling material.

One end of the voltage dividing resistor 4 is connected to a metal screw 19 for connection to the terminal 3, and is fixed by an insulating jig 20 such as a diuracon. In addition, the compensation capacitor 6 has a cylindrical compensation plate made of aluminum or copper arranged around the voltage dividing resistor 4, and a filler filled between the compensation plate and the voltage dividing resistor 4 to form a capacitor. It forms a compensation capacitor.

The other end of the voltage dividing resistor 4 is collectively connected to the voltage dividing resistor 5, compensation capacitors 6, 7, and protection diode 8 to a first collective connection point, and a signal line 9 is connected to the first collective connection point. and is led out by cable C. In addition, the voltage dividing resistor 5 and the compensation capacitor 7
and the other ends of the protective diodes 8 are collectively connected to a second collective connection point, and a ground wire E is connected to the second collective connection point, and the cable C and the ground wire E
is fixed within the insulating case 21 by a fixing jig 26.

Further, the outer periphery of the insulating case 21 is surrounded by an insulating coating 23 such as a silicon tube, thereby improving the insulation properties and mechanically reinforcing the insulating case 21 itself. Further, the outside of the insulating coating 23 is covered with a shield case 24 made of aluminum, copper, or the like, and the shield case 24 itself is connected to the ground wire E via a shield ground wire 27. The shield case 24 eliminates interference due to stray capacitance between the probe P and the outside,
The performance as a voltage detection probe is improved, and at the same time, the mechanical strength of the probe P itself is improved. Furthermore, the outer periphery of the shield case 24 is
It is covered with an insulating coating 25 such as a silicon tube to further improve insulation.

The probe P according to the present invention is
Figure 4 shows an example of safety measures when connecting with That is, in the above embodiment, the protection diode 8 was built into the probe P, but the fourth protection diode 8 was built into the probe P.
As shown in the figure, a protective diode 29 may be inserted at the input end of the input circuit section 30 of the processing device 28, and it serves as a safety measure against overvoltage application no matter where it is inserted.

In the above embodiment, the conductor 2 was constituted by the insulated cable 14, but depending on the purpose of use, the terminal 1 and the insulating case part 10 may be integrated into the insulating case 16 part of the terminal 3. is also possible.

Moreover, the voltage detection probe P in the above embodiment
shows the structure of terminal 1 and terminal 3 when connecting between ignition coil IG and coil cord IC, but by changing the structure of terminal 1 and terminal 3, coil cord IC and distributor RO can be connected. Needless to say, it can be easily installed between the center electrode parts, between the outer electrode of the distributor RO and the plug cord PC, or between the plug cord PC and the spark plug PL.

As explained above, the voltage detection probe according to the present invention can be installed extremely easily in the ignition circuit of an internal combustion engine of an automobile, etc., and can safely and reliably detect the secondary voltage including DC components to high frequency components with high precision. Therefore, it is extremely suitable for the manufacturing process of engines, etc., or during inspection and maintenance of automobiles.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an example of an ignition circuit for an internal combustion engine to which an embodiment of the voltage detection probe according to the present invention is connected, and FIG. 2 is a circuit diagram showing an internal circuit of the embodiment of the voltage detection probe. , Figure 3 also shows,
FIG. 4, which is a sectional view showing a specific structure, is a circuit diagram showing a state in which the embodiment is connected to an external processing device. IG...Ignition coil, IC...Coil cord, RO...Distributor, PC...Plug cord, PL...Ignition plug, P...Voltage detection probe, C...Cable, E...Ground wire,
1, 3...terminal, 2...conductor, 4,5...divider resistance,
6, 7...Capacitor, 8...Protection diode, 9
…Signal line.

Claims (1)

[Scope of Claims] 1. A voltage detection probe for directly detecting an electrical signal from an ignition circuit of an internal combustion engine whose components include an ignition coil, a coil cord, a distributor, a plug cord, a spark plug, etc. A conductor inserted between components of a circuit, the ends of which are provided with fitting parts that can make electrical contact with the connections between the components, and a first partial voltage whose one end is connected to the conductor. a second voltage dividing resistor and a capacitor having one end collectively connected to a first collective connecting point of the other end of the first voltage dividing resistor and the other end collectively connecting to a second collective connecting point; , a cylindrical capacitive plate disposed around the circumference of the first voltage dividing resistor, connected to the first collective connection point to form a capacitor; It is composed of a signal line, a ground line connected to the second collective connection point, and a case made of an insulating material that houses the first and second voltage dividing resistors, a capacitor plate, and a capacitor. A voltage detection probe characterized by: 2. The voltage detection probe according to claim 1, wherein a protection diode is connected between the first collective connection point and the second collective connection point.