JPS58144623A - Ignition device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To enable a stable ignition to be achieved by an arrangement wherein an ignition plug is mounted near the outer periphery of a cylinder and an wind- shield member for the ignition plug is mounted upstream of a swirl flow in the cylinder thereby preventing the flame caused by ignition from being flown out by the swirl. CONSTITUTION:The outlet part of an air intake port 3 is formed in a helical port 3A so that the mixture of air and fuel drawn through an air inlet valve 5 into the cylinder may cause a swirl. Further, an ignition plug 8 is mounted on a cylinder head 2 so that an ignition cap 15 of the plug is located in the peripheral part of a combustion chamber 7 or in the outside part of the swirl. In this case, a semi-circular projection 16A serving as a wind-shield member 16 is formed near the upstream side of the ignition plug 8 relative to the swirl air flow to prevent the flame at the ignition plug 15 from being blown out. This arrangement prevents the spark generated across the ignition plug 15 from being blown out by the intense swirl air flow so that a stable ignition of the enriched air-fuel mixture layer can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates primarily to a fuel ignition device for a fuel-injected internal combustion engine.

In premixed internal combustion engines such as gasoline engines, in order to improve acceleration response etc., fuel is injected and supplied to the engine intake port in synchronization with ffk110 rotation, and swirl is also generated to give swirling motion to the air-fuel mixture in the cylinder. Some have measures in place.

To explain this with reference to Fig. 1, the intake manifold 1
A fuel injector 4 is installed near the intake port 3 of the cylinder head 2.

The injection direction of this injector 4 is set so as to inject fuel toward the vicinity of the back of the intake valve 5. For example, in a 4-cycle engine, fuel is intermittently injected once per rotation, and the fuel is injected into the intake valve. When the valve 5 opens, the air is drawn into the cylinder 6, that is, into the combustion chamber 7 together with air.

At this time, the intake port 3G is formed into a helical port 3A as a swirl generating means so as to impart swirling motion to the intake air flow.

Therefore, the air flowing into the cylinder causes a swirl around the cylinder axis, and this swirl is sustained from the suction stroke to the compression stroke. - Then, as the piston 9 rises, near the first compression dead center f-1, the ignition plug 8 generates a spark fIi to ignite and burn the air-fuel mixture.

By the way, the fuel injected from the injector 4 is
Until the intake valve 5 opens, it adheres to the back surface of the intake valve 5 and the inner wall of the intake port 3, and during the intake stroke when the intake valve 5 opens, it flows into the cylinder along with the intake air flow.

Therefore, most of the fuel is sucked into the cylinder at the beginning of the intake stroke, forming a rich mixture layer at the bottom of the cylinder, and due to the swirling movement of the intake air within the cylinder, the fuel particles are subjected to centrifugal force and moved outward. , a relatively dense mixture layer is also formed along the inner wall of the cylinder.

As a result, the air-fuel mixture in the center of the cylinder where the ignition plug 8 is attached becomes S-lean, and even if the ignition plug 8 discharges a spark, depending on the operating conditions, ignition may not occur stably, or ignition may not occur stably. Subsequent flame propagation was not carried out smoothly, and combustion sometimes became unstable.

The present invention was proposed in order to solve this problem.

The spark plug is installed close to the outer periphery of the spark plug, and a windproof member is placed near the spark plug to reliably ignite the rich air-fuel mixture layer and ensure stable combustion even under strong swirls. Provide an ignition device.

Embodiments of the present invention will be described below based on the drawings.

In FIGS. 2 and 3, the outlet of the intake port 3 is formed into a helical port 3A so that the air-fuel mixture sucked in from the intake valve 5 swirls within the cylinder.

The ignition plug 8 is attached to the cylinder head 2 so that the ignition cap 15 is located at the periphery of the combustion chamber 7, that is, at the outer side of the swirl.

The upstream side of the spark plug 8 with respect to the swirl air flow (completely,
A windproof member 16 as shown in FIGS. 4(A> and 4B) is formed (however, FIG. 4(B) 1.
).

The windproof member 16 is formed as a semicircular projection 16A, and prevents the flame from blowing out at the ignition cap 15.

Note that 18 is an exhaust valve, 19 is an exhaust port, and in this case, the intake and exhaust ports 3 and 19 have a cross-flow structure.

In other parts of the structure, the same members as in FIG. The air is sucked into the cylinder while swirling around the intake valve 5 along with the air, creating a swirl along the inner wall of the cylinder 6.

At this time, the already vaporized fuel goes into series with the air.
・Also distributed in the central part of Da. However, all of the fuel injected upstream of the intake valve 5 does not immediately vaporize, but much of it is sucked into the cylinder in the form of droplets.

Since fuel droplets have a large mass, when a strong swirl occurs, most of them are directed toward the inner wall of cylinder 6 due to centrifugal force.
I was thrown and blown away.

In the compression stroke in which the piston 9 begins hu, even though the fuel vaporization progresses, a swirling layer containing dense U air is maintained near the wall surface of the cylinder 6.

As a result, near compression top dead center, it is possible to ignite the spark plug B LL in the Sawa Aiki region on the outer periphery of the cylinder, which is richer than the overall average air-fuel ratio.At this time, although the swirl flow is strong on the outer periphery, Windproof member 16 provided on the upstream side of plug 8
As a result, the sparks that fly to the ignition valve 15 are prevented from blowing out, and stable ignition is achieved.

After ignition, due to the inherent function of swirl, the flame creates a turbulent flow while smoothly propagating into the relatively dilute air-fuel mixture layer in the center, ensuring stable combustion.

FIG. 5 shows an embodiment in which the arrangement 1'' of the intake and exhaust ports is not relative to the cross 70- as shown in FIG. 2, but is relative to the counter flow.
The ignition plug 8 is located on the outer peripheral side of the cylinder, and a windproof member 16 is provided on the upstream side of the swirl. Therefore, ignition occurs in the outer peripheral region of the cylinder where the mixture is richer than in the center, so stable combustion can be ensured.

The embodiments shown in FIGS. 6 and 7 have cross-flow type intake and exhaust boats, and the intake boats I-0 and exhaust boats 1 to 19 are moved from the center of the cylinder to A face 1 to create an intake swirl. It is designed to occur.

In this case, the position of the spark plug is 8Δ or 8B in the figure.
It is set near the middle between the intake valve 5 and the exhaust valve 18 in the cylinder outer peripheral area.

A recess 21 in a screw hole 20 of a spark plug 8 is used as a windproof member 16. That is, the recess 21 is formed by installing the ignition plug 8 at an angle and setting the ignition gap 15 to such an extent that it does not protrude from the cylinder head wall surface. Note that the ignition plug 8 is tilted so that the back side of the ignition plug 8 faces in the direction of the swirl.

In this case, since there is no protrusion on the inner surface of the combustion chamber 7,
Swirl is less likely to be attenuated and sufficient effect can be achieved.

According to the present invention, the ignition plug is arranged in the outer peripheral area of the cylinder where a rich air-fuel mixture exists, and the ignition flame is not blown out by a strong spark. As a result, stable combustion can be carried out in a rich air-fuel mixture layer, and in particular, it is possible to achieve wide and lean combustion as a whole, and improve fuel efficiency by 35% due to improved combustion efficiency.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional device. FIG. 2 is a sectional view of the first embodiment of the present invention, FIG. is a sectional view of the second embodiment, FIG. 6 is a bottom view of the cylinder head of the ?83 embodiment, and FIG. 7 is a sectional view of the windshield member. 1...Intake manifold, 2...-Cylinder head,
3... Intake port, 3Δ... Edge Calport 1~. 4
River fuel injection injector, 5... Intake valve, 7... Combustion chamber, 8... Spark plug, 15... Ignition gap, 16
...Windbreak part (A, 19...Exhaust port. Patent applicant: Nissan Motor Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 6 Figure 7

Claims (1)

[Claims] -In an internal combustion engine that is equipped with an ignition plug that ignites and burns the air-fuel mixture in the combustion chamber and is equipped with a swirl generating means in the intake system, the above-mentioned ignition plug is arranged near the outer periphery of the cylinder, and the cylinder of this ignition plug is An ignition device for an internal combustion engine, characterized in that a windproof member is provided on the upstream side with respect to an internal swirl flow.