JPS6119923A - Ignition device in internal-combustion engine - Google Patents

Abstract

PURPOSE:To spark a spark gap which has much chances to come into contact with atomized fuel which is formed at a shifted injecting position, by arranging a plurality of ignition electrodes in the peripheral section of a space through which atomized fuel stream from a fuel injection device passes, circumferentially with respect to the axial direction of the atomized fuel stream, and by arranging spark gaps formed by the electrodes in parallel with each other. CONSTITUTION:An atomized fuel stream injected from a jet port in a fuel injection valve reaches a through-hole 4, and is evaporated successively from liquid drops. The thus evaporated fuel is mixed with air introduced from the outer peripheral edge of the atomized fuel stream to form a burnable mixture while the evaporated fuel passes through spark gaps 23 formed between high voltage side electrodes 11 and grounded electrodes 13 and moves toward a vortex chamber. One of spark gaps 23 which is easiest to spark, generates a spark while the other spark gaps 23 do not spark since the spark gaps 23 establish the indefinte number of paralle gaps, equivalent to a high ignition voltage supply section 12. Accordingly, even if the position of the atomized fuel stream is shifted, natural spark is effect at a spark gap 23 which has a maximum possibility to come into contact with this atomized fuel, so that a spark initiation demand voltage may be made lower.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention generally relates to an ignition system for an internal combustion engine, and more particularly to an ignition system for an internal combustion engine equipped with a fuel injection device.

[Prior art and its problems] Even in internal combustion engines, especially diesel engines, which compress and ignite the fuel injected into the combustion chamber, spark plugs are provided with the intention of improving ignition performance when the fuel is cold. A device that ignites in synchronization with injection has been published (Komatsu Giho, published April 25, 1980).

FIG. 2 shows the above-mentioned ignition 'IN' position. In this device, the ignition position of the ignition plug 113 is provided far away from the nozzle 103 of the fuel injection valve 101, and the discharge part 105 is only emitted from one location. It uses a so-called one-point ignition power type that does not produce sparks. Therefore, a considerable amount of fuel is injected while the fuel spray reaches the ignition position, so the combustion state is that the injected fuel is burned sequentially (rather than stratified combustion, it is premixed with air). The ratio of premixed combustion, in which fuel is combusted with a time delay, increases, resulting in a problem in which diesel knock is more likely to occur, especially when idling at low engine speeds.

Therefore, a new proposal has been made to improve this problem (Utility Application No. 172゜080/1980). The outline of the proposal is as follows.

That is, an ignition M pole to which a high ignition voltage is applied, a plurality of discharge intermediate electrodes, and a ground electrode are arranged at equal intervals in the circumferential direction around the vicinity of the tip of the fuel injection valve's jet port facing the swirl chamber. At the same time, the gap formed by each electrode (that is, the gap) is set to a predetermined width to form a discharge gap (discharge gap), and these gaps are configured as a series gap (so-called multi-point ignition method).

However, in the above configuration, since the ignition gap formed by each electrode is configured as a series gap, the voltage required to start discharge is the sum of the required voltages applied to each of the ignition gear V-tubes. Therefore, high voltage is required. Therefore, even when igniting a location in an optimal spray state where the required voltage is low and ignition is most likely to occur, an unnecessarily high voltage is applied. In addition, in order to ensure h-current exchange at the intermediate electrode, it is necessary to maintain a distance between the ignition electrode and the ground electrode at a predetermined value or more, so it is not possible to arrange the electrodes evenly around the outer edge of the fuel spray. . Therefore, if the fuel injection position shifts due to changes in engine operating conditions or deterioration of the fuel injection valve, the location where the optimal spray condition is most likely to ignite has moved to a part where the electrode spacing is relatively large. However, there was a problem that ignition became unstable because the chances of contact between the atomized fuel and the ignition spark decreased.

[Purpose] Therefore, the present invention has been made in view of the above-mentioned problems of the prior art.The purpose of the present invention is to simplify the structure of the ignition gap so that the required voltage applied to the spark plug is low and consistent with the operating conditions of the engine. The ignition system for internal combustion engines is capable of stable ignition, which can generate spark discharge at the point where there is the most contact with the injected fuel even if the injection position of the fuel shifts due to changes in the fuel injection valve or deterioration of the fuel injection valve. It is about providing.

[Configuration] A feature of the present invention for achieving the above object is that, in an internal combustion engine equipped with a fuel injection device, a power supply side electrode and a ground side electrode are provided at the periphery of a space through which a spray stream injected from the fuel injection device passes. An internal combustion engine in which ignition electrodes facing the electrodes are disposed circumferentially with respect to the axial direction of the spray flow, and the ignition gap formed by the facing electrode portions is continuously configured as shown in FIG. in the ignition system.

[Action] In the above configuration, the supplied ignition high current 1tE
Spark discharge occurs at the point where the air-fuel mixture in the optimum spray state (that is, close to the stoichiometric air-fuel ratio) reaches the ignition gap, so the required voltage at the start of discharge is low. It is possible to improve the stability of ignition.

: ノ5/11! ! Example] The present invention will be explained in detail below with reference to the drawings. Furthermore, Figure 1,
In Figures 3 to 6, (b and reference number 8 and t) indicate the same item.

1) Figures 1, 31, and 4 show an ignition system for an internal combustion engine (such as a diesel engine) according to the first embodiment of the present invention.

In Fig. 1, a3 shows the part of the fuel oil injection valve 1 near the whirlpool 7 and the ignition high voltage supply part 1 of the high tension cord 15.
Is the outer periphery of each part closer to 2 a holder? 5 (this 1 me) has been done. The holder 25 is attached to the cylinder head 19. A discharge electrode portion 5 is provided on the vortex chamber 7 side of the fuel injection valve 1 in close proximity to the injection valve 1, and the discharge electrode portion 5 has an abbreviated cross section at its outer periphery. , the ends of which are in contact with the ends of the holder 25 and have washers 22.
It is supported by a shrine 21. The metal support part +)
J21 is also attached to the cylinder head 19.

The front d discharge electrode part 5 is connected to the fuel a (1.
The main combustion chamber 1 is connected to the main combustion chamber 1 through the nozzle hole 1 (3) adjacent to the discharge electrode part 5.
A vortex stream ¥7 communicating with 7 is provided.

The discharge electrode section 5 is arranged in a direction 17i of the vortex chamber 7.
An insulating ring 9 whose surface has a shape as shown in FIG. 3 and has a through hole 4 formed in the center, a high voltage side electrode 11 formed in a ring shape at the outer edge of the through hole 4, and the electrode. The ground electrode 13 is formed in a ring shape and faces the ground electrode 11 . The spout 3 faces the through hole 4,
The through hole 4 forms a passage space for the spray flow from the jet nozzle 3 to the high voltage side electrode and the ground electrode 13. A gap 23 is formed continuously over the entire circumference, and faces the front outlet passage hole 4. High tensile strength that is not connected to the ignition coil ~1 ~ 15
is connected.

FIG. 3 (,1) L of the internal combustion engine according to the first embodiment of the present invention
Figure 4 is a cross-sectional view of the main parts of -+7 fire equipment, and ■-I in Figure 3.
VI! i! It shows a cross-sectional view.

In FIG. 3C, the extended portion of the high voltage side electrode 11 that reaches the ignition high voltage supply section 12 is directly supported by the insulating ring 9 as shown in the figure, and the ring-shaped portion formed on the outer edge 811 of the through hole 4 is It is supported by the insulating ring 9 via the support part 29. The ground electrode 13 is the high voltage side electrode 1
A metal support member is provided in a ring shape on all 7 sides of the vortex opposite to the vortex 1, and is disposed around the entire circumference at the outer edge of the through hole 4 on the vortex chamber 7 side via the support part 14. Supported by 20. The ground electrode 13 is connected to the front metal support portion 21 on the entire circumference of the metal support member 20 as shown in FIG. 4 (the surface facing the vortex chamber 7). , and is configured to receive (lk discharge current) from the 0-side electrode 11 through the ignition gap 23 and ground it to the shilling head 19 through the support member 20.21.

The ignition gap 23 formed by the high-voltage side electrode 11 and the contact point 13 is a parallel gap shown by an arrow in FIG. It is formed continuously with grooves around the circumference. Therefore, the ignition gap 23 is equivalent to innumerable parallel gaps formed with respect to the ignition high voltage supply section 12 (41)! Therefore, the discharge current given from the ignition high voltage supply section 12 at the ignition timing is applied to the ignition gear [・tub 2
If a discharge occurs in the part of 3 where discharge is most likely to occur, no discharge will occur in other parts.

The operation of the above configuration will be explained below.

The spray flow split from the jet D 3 of the fuel injection valve 1 reaches the through hole 4 . The spray stream sequentially evaporates from the droplets and mixes with air drawn in from the outer edge of the spray stream to form a flammable mixture at the outer edge of the spray stream, while the high voltage side type If
Ignition gear 11 knob 23 formed by i11 and ground electrode 13
and continues moving toward the vortex chamber 7.

On the other hand, when the l171 fog stream approaches the ignition gap 23, W
], an ignition high voltage is applied to the ignition high voltage supply section 12 via an ignition coil (not shown) and a high tension cord 15. The ignition high voltage applied to the supply section 12 causes the ignition gap 23 to discharge the most since, as described above, an infinite number of parallel gaps are equivalently formed with respect to the ignition voltage supply section 12. Avoid generating discharge in areas where it is likely to occur, and do not generate discharge in other areas. After a discharge has occurred in that part of the ignition gap 23, the discharge current is grounded to the cylinder head 19 via the support member 20.21.

The spray stream flows from the main combustion chamber 17 to the nozzle hole 1 depending on the operating condition of the engine (for example, changes in engine speed and load on the engine).
Since the influence of the swirling flow caused by the air flowing into the vortex chamber 7 through the vortex chamber 7 may alternate, the air-fuel mixture in the optimum atomized state where it is most likely to ignite is located at any part within the above-mentioned ignition gap 23. It is unclear whether it will move towards. However, even if the air-fuel mixture in the optimal spray state moves to any of the above-mentioned parts, the part that has the most chance of contact with the air-fuel mixture (a natural discharge occurs, and once the discharge is completed in that part, the other parts will also be shifted to A). Since the discharge does not exceed 1, a reliable 71 fire can be expected with a lower electric power requirement than that of the series gap.In this way, the spray stream injected from the jet L3 has its tip close to the ignition gap. 23, 4 fires start from the tip and expand. As mentioned above, even if the arm 1-11 in the optimum wA3 state moves, it will ignite reliably, so for example, if the injection valve "1" Even if the position of the spray stream shifts due to deterioration of the fuel, the discharge will occur naturally in the areas that have the most contact with the spray stream, so the required voltage to start the discharge is low and unstable, and the stability of ignition is impaired. There isn't.

1, 5 and 6 show an ignition system for an internal combustion engine (particularly a diesel engine '4) according to a second embodiment of the present invention. The difference between this embodiment and the first embodiment is that as shown in FIGS. The semiconductor thin film 27 is provided in the ignition gap 23 to guide the creeping discharge generated in the ignition gap 23. Since the discharge current generated in the ignition gap 23 can be effectively utilized, the discharge current generated in the ignition gap 23 can be effectively utilized.
It is possible to further reduce the required voltage at the start of discharge than in the configuration of the embodiment.

As explained above, according to the first and second embodiments according to the present invention, the atomized fuel supplied from the fuel injection valve is not ignited due to the temperature increase of the air due to compression;
Since the ignition gap is formed all around the outer edge of the atomized fuel and the required voltage at the start of discharge is low, it is ignited by the ignition plug, so it is easy to use even with high compression ratio engines such as Diegel engines. Can be ignited. Also, cold 1
C
According to 4R, it is possible to use low cetane fuel. J5 The above-mentioned contents are merely examples according to the present invention, and the ignition system according to the present invention is not limited to diesel engines, but can also be applied to, for example, gasoline engines with a swirl chamber having a width of λ or direct injection type gasoline engines. It is set up.

[Effects] As explained above, according to the present invention, the ignition electrodes in which the source-side electrode and the ground-side electrode face each other are disposed in the circumferential direction with respect to the axial direction of the spray flow, and the Since the ignition gap formed by the electrode part is opened in parallel and continuously, the structure of the ignition gap is simple, the required voltage applied to the spark plug is low, and it can be adjusted to the operating conditions of the engine. Even if the fuel injection position shifts due to changes or deterioration of the fuel injection valve, lJ! at the ignition gear V knob! Since spark discharge can be generated at a location where there is the greatest chance of fusion with fog fuel, it is possible to provide an ignition device for an internal combustion engine that is capable of stable ignition.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of an ignition system for an internal combustion engine according to the first and second embodiments of the present invention, and FIG. 2 is a partial sectional view of an ignition system for an internal combustion engine according to the prior art! FIG. 3 is a cross-sectional view of essential parts of an ignition system for an internal combustion engine according to the first embodiment of the present invention, and FIG. 4 is a cross-sectional view taken along line IV-1v in FIG. 5 is a sectional view of a main part of an ignition system for an internal combustion engine according to a second embodiment of the present invention, and FIG. 6 is a sectional view taken along the line vi-Vl in FIG. 1...Fuel injection valve 3...Ejection port 4...Through hole 5...Discharge electrode part 9...Insulation ring 11...High voltage side type I cell 12...Point large elevation L [Supply part 13...Ground electrode 14...One support part...Cylinder head 20...Metal support part) A 21...Metal support member 23...Ignition gap 27. ... Semiconductor thin film 29... Support part 1111 Figure 2 Figure 11 107 Figure 3 Fourth factor +I 9 ZU Ij ? UFigure 5

Claims (1)

[Claims] In an internal combustion engine equipped with a fuel injection device, an ignition electrode, in which a power supply side electrode and a ground side electrode face each other, is arranged in the periphery of a space through which a spray stream injected from the fuel injection device passes, with respect to the axial direction of the spray stream. An ignition device for an internal combustion engine, characterized in that the ignition gaps formed by the opposing electrode portions are parallel and continuous.