JPH0614034Y2 - Internal combustion engine ignition device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention has a cavity formed in a piston, and an injection nozzle is provided at a position facing the center of the cavity on the cylinder head side, and the injection nozzle has at least three injection holes. Is on one side of the cavity, and there is no injection port on the other side.The fuel spray is injected from one of these injection ports to one side of the piston cavity to inject it into a high load spark plug and a low load spark plug. TECHNICAL FIELD The present invention relates to an ignition device for an internal combustion engine that ignites by using.

[Prior Art] Recently, there has been developed an internal combustion engine, which is a so-called alcohol engine, in which a low cetane number fuel (for example, methanol or ethanol) is injected in a cylinder and ignited by an ignition plug.

In this type of engine, if fuel is injected into the entire cavity, combustion is good at high load but bad at low load. Therefore, as shown in FIG. 7, fuel is injected toward one side of the cavity V. ing. In the figure, arrow S is swirl and E
1 to E4 are sprays, J1 to J4 are the center lines of the nozzles,
P1 and P2 are the center lines J of the nozzles in the sprays E1 and E4.
1, spark plugs arranged at the same position on the downstream side of the swirl S from J4. Therefore, the spark plug P1 will be described below.

By the way, in FIG. 8 showing the AA ′ cross section (cross section perpendicular to the center line J1 of the injection port including the ignition plug P1) in FIG. 7, a plane B parallel to the cylinder head passing through the ignition plug P1.
The mixture concentration F / A at -B 'is as shown in FIG. Note that Ha in FIG. 8 shows the lower surface of the cylinder head. That is, since the spray is swirled by the swirl S,
The mixture concentration F / A spreads to the downstream side of the swirl S. Here, assuming that the angle from the center line J1 of the injection port of the spark plug P1 is a, if the angle a is not in the ignitable plug position K that falls within the flammable range G indicated by the oblique line of the mixture concentration F / A, ignition is not performed. It won't happen. However, the mixture concentration F / A, that is, the spread of the spray changes depending on the load and the engine speed of the engine, and the ignitable plug position K is located at a position away from the center line J1 of the injection port when the load is high, as shown in FIG. It becomes KH, and when the load is low, as shown in Fig. 11, the center line J
The position is KL close to 1. Therefore, the above-mentioned spark plug P1
At the position, there was a problem that ignition could not be stably obtained corresponding to all engine loads, fuel consumption deteriorated, and exhaust gas deteriorated due to unburned fuel. In addition, the actual Kaisho 61-6
Japanese Patent No. 6670 proposes a starting assist device for a diesel engine.

[PROBLEMS TO BE SOLVED] Therefore, an object of the present invention is to provide an ignition device for an internal combustion engine capable of improving ignitability over the entire range of engine load.

[Means for Solving the Problem] According to the present invention, a cavity is formed in a piston, and an injection nozzle is provided at a position facing the center of the cavity on the cylinder head side, and the injection nozzle has at least three injection ports on one side of the cavity. It has, and does not have an injection port on the opposite side, and sprays fuel spray from those injection ports to one side of the piston cavity and ignites it using a high load spark plug and a low load spark plug. In the ignition device for an internal combustion engine, the high-load spark plug is located upstream of the swirl with respect to the low-load spark plug with respect to the spray injected to one side, and the high-load spark plug is located at the most upstream side. Is provided at a position at an offset angle α from the center line of the injection port to the downstream side of the swirl in the spray of, and the low load spark plug is located on the most downstream side of the spray in which the high load spark plug is located. Downstream of the swirl from the center line of the nozzle hole in the mist is provided at a position of the biasing angle beta, biasing angle of the spark plug for the high load α
Is larger than the deviation angle β of the low load spark plug, and the high load spark plug is located at a position of 60 to 90% of the injection radius in the radial direction, and the low load spark plug is It exists at a position of 40 to 60% of the injection radius in the radial direction.

[Explanation of action and effect] The spread of the spray becomes large when the load is high, and relatively small when the load is low. Therefore, in the present invention, both spark plugs are provided at the optimum positions, and when the load is high, the high load spark plug ignites, and when the load is low, the low load ignition nozzle ignites, and stable ignition is achieved over the entire load range. Therefore, fuel consumption and exhaust gas can be improved.

Also, when the load is high, the air-fuel mixture becomes rich and it is easy to ignite,
When the load is low, it becomes lean and difficult to ignite. However, in the present invention, since the low load spark plug is located downstream of the swirl of the high load spark plug with respect to the spray injected on one side, the swirl causes the spray on the upstream side to the low load ignition nozzle. It becomes easier to ignite.

Thus, according to the present invention, the ignitability can be improved regardless of the load.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the cylinder head H is provided with an injection nozzle N toward the piston cavity V, and a high load ignition plug PH and a low load ignition nozzle PL.

In FIGS. 2, 5, and 6, the spark plug PH
Is provided in the spray E1 at a position at an angle α from the center line P1 of the nozzle toward the downstream side of the swirl S, and the spark plug PL is the spray E4.
Inside, it is provided at a position of an angle β from the center line J4 of the nozzle to the downstream side of the swirl S. That is, both spark plugs PH,
PL is located downstream of the swirl S from the center line of the nozzle,
The plug PL is arranged on the downstream side of the swirl S in the spray area Z. Then, the angle α> the angle β, that is, the angle α is within the range of the ignition plug position KH capable of igniting shown in FIG. 10 and close to the lower limit of the flammable range G, and the angle β is the ignition plug position capable of igniting the ignition position of FIG. It is determined to be within the KL range and close to the upper limit of the flammable range G.

Further, as shown in FIG. 3 and FIG.
Distance RH from the center line J1 of the injection port and distance RL from the center line J4 of the injection plug PL are: distance RH> distance R
It is L. That is, the spray spreads in a conical shape from the injection nozzle, but the radius r of the spray in a cross section perpendicular to the center line of the injection port including the spark plugs PH and PL (this is called the injection radius).
Then, RH = (60 to 90%) r, RL = (40 to 90)
60%) r, that is, the plug PH is located far from the center line V1 of the injection port, and the plug PL is located close to the center line V4 of the injection port.

During operation, the high-load ignition plug PH ignites when the load is high, and the low-load ignition plug PL ignites when the load is low to obtain stable ignition over the entire load range, thereby improving fuel consumption and exhaust gas. . At this time, it is possible to save the electric power by stopping the ignition of the low load spark plug PL at the time of high load and stopping the ignition of the high load spark plug PH at the time of low load by means not shown.

[Effects of the Invention] As described above, the present invention has the following excellent effects.

(I) Since the high load spark plug is provided at a relatively lean position of the air-fuel mixture and the low load spark plug is provided at a relatively rich position for one spray,
Good ignitability regardless of load.

(Ii) Since the low load spark plug is provided at a position where the air-fuel mixture flows due to the swirl, even if the air-fuel mixture is lean, all the sprays overlap and become rich, and the ignitability is good.

(Iii) It is possible to obtain stable ignition over the entire load range and improve fuel and exhaust gas.

[Brief description of drawings]

1 is a side sectional view of a cylinder head showing an embodiment of the present invention, FIG. 2 is a top view showing the arrangement of spark plugs, FIG. 3 is a sectional view taken along the line CC ′ of FIG. 2, and FIG. Is DD 'in FIG.
Sectional drawings, FIG. 5 and FIG. 6 are drawings showing the air-fuel mixture concentration in a horizontal section passing through the spark plugs of FIG. 3 and FIG. 4, respectively. FIG. 7 is a drawing corresponding to FIG. 8 is a sectional view taken along the line AA 'in FIG. 7, and FIG. 9 is a sectional view taken along the line BB' in FIG.
FIGS. 10 and 11 are views showing a mixture concentration in a cross section, and FIGS. 10 and 11 are views for explaining desirable ignitable plug positions at high load and low load, respectively. E1-E4 ... Spray, G ... flammable range, J1-J4 ...
Center line of injection port, K, KH, KL ... Ignition possible plug position, N ... Injection nozzle, PH ... High load ignition plug,
PL: low load spark plug, S: swirl, V:
Cavity, Z ... Spraying area

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI technical display location F02P 15/08 302 A (72) Inventor Naoya Harayama 1-chome, Ageo-shi, Saitama Nissan Diesel Kogyo Co., Ltd. (56) Bibliography Sho 62-183076 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A cavity is formed in a piston, and an injection nozzle is provided at a position facing the center of the cavity on the cylinder head side. The injection nozzle has at least three injection ports on one side of the cavity and an injection port on the opposite side. I don't have
In the ignition device of an internal combustion engine in which fuel spray is injected from one of these nozzles to one side of the piston cavity, and is ignited by using a high load spark plug and a low load spark plug, On the other hand, the high-load spark plug is located upstream of the swirl with respect to the low-load spark plug, and the high-load spark plug is located within the spray on the most upstream side from the center line of the nozzle to the downstream side of the swirl. The spark plug for low load, which is provided at the deviation angle α, is biased toward the downstream side of the swirl from the center line of the nozzle in the spray on the most downstream side of the spray where the spark plug for high load is located. The deviation angle α of the spark plug for high load, which is provided at the position of the deviation angle β, is larger than the deviation angle β of the spark plug for low load,
And the spark plug for high load is 60 in the radial direction.
An ignition device for an internal combustion engine, wherein the ignition plug for low load is located at a position of ˜90%, and the low load spark plug is located at a position of 40% to 60% of the injection radius in the radial direction.