JPS5925101B2 - internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine that is capable of reducing harmful components, particularly NOx, in exhaust gas and at the same time improving fuel efficiency.

In recent years, there has been a demand for internal combustion engines for automobiles that not only purify exhaust gas but also improve fuel efficiency.

For this reason, EGR (exhaust gas recirculation) and lean burn are often performed, but in order to satisfy the requirements of both high-volume EGR and lean burn while preventing combustion fluctuations and misfires, it is necessary to increase the combustion speed. Are known. In order to increase this combustion speed, recently, a sub-intake passage is provided separately from the main intake passage, and gas is injected into the combustion chamber from the sub-intake passage to generate a swirl of intake air in the combustion chamber. Several things have been proposed.

However, devices having this sub-intake passage are in the transitional range of practical use, and much depends on future research.

In fact, with conventional systems, the momentum of the swirl generated is not sufficient, so if a large amount of EGR is performed with priority given to exhaust gas countermeasures, especially N0x reduction, there will be a limit to lean combustion, resulting in a significant reduction in fuel consumption. There was no hope for any significant improvement.
The present invention solves the above-mentioned problems, and creates a sub-intake passage that can generate a stronger intake swirl than before, thereby increasing the limit of lean combustion and obtaining good results. The purpose of this invention is to provide an internal combustion engine that facilitates The present invention was made as a result of various studies on the influence of the shape, dimensions, etc. of the downstream end of the sub-intake passage on the force of the swirl of intake air. It is characterized in that the length of the injection nozzle portion, that is, the diameter-reduced portion is larger than the inner diameter of the injection nozzle. Embodiments of the present invention will be described below with reference to the drawings. In Fig. 1, 1 is a cylinder;
2 is a cylinder head, 3 is a piston, and 4 is a combustion chamber, into which a main intake passage 5 is opened. The main intake passage 5 is configured as a series of passages leading to an air cleaner 9 via an intake boat 6 formed in the cylinder head 2, an intake manifold 7, and a two-barrel carburetor 8 serving as a fuel supply device. The intake boat 6 is oriented in a direction that generates a swirl around the axis of the cylinder 1 in the combustion chamber 4, and the direction of the swirl is such that the air-fuel mixture supplied from the intake boat 6 reaches a spark plug (not shown). After sweeping the
It is designed to flow into the exhaust boat 10.

Both boats 6 and 10 are opened and closed by the intake valve 11.
Both valves 11 and 12 are operated by return springs 13 and 14,
Cams 16 and 17 rotationally driven by the camshaft 15
, rocker arms 18, 19, etc., and when the valve is closed, the valve seat 20
, 21. Reference numeral 22 denotes a sub-intake passage having an effective opening area smaller than that of the main intake passage 5; A passage 22C formed in the main body 8a of the vaporizer 8 and the passage 2
It is composed of two inlet ends 22D and 22E that are branched from 2C into two and open into the primary side ventilation passage 8b of the carburetor 8, respectively.

Both inlet ends 22D, 22E are spaced apart from each other in the flow direction of the ventilation passage 8b, and the upstream inlet end 22D is opened between the primary pendant valve 8c of the carburetor 8 and the primary throttle valve 8d. ing. In addition, the downstream inlet end 22E
is opened at a position where it is closed by the primary throttle valve 8d in the closed position (idling position). On the other hand, the tip part (combustion chamber 4 side end part) of the vibe material 22A constituting the outlet end of the sub-intake passage 22 functions as a diameter-reduced injection nozzle 22a in the main intake passage just upstream of the intake valve 11. 5 and is opened there, and the remaining portion is buried in the cylinder head 2 as a large-diameter boss portion 22b.

The length 1 of the injection nozzle 22a is larger than the inner diameter d of its tip. The injection nozzle 22a is slightly bent with respect to the boss portion 22b so as to be oriented in a tangential direction to the combustion chamber 4 in order to generate a swirl centered on the axis of the cylinder 1. Of course, the swirling direction of the gas injected from the injection nozzle 22a is such that it flows into the exhaust boat 6 after sweeping the spark plug. The degree of this bending is determined by the substantially straight boss portion 22b.
When the axis of the injection nozzle 22a is O and the outer diameter is D, the injection nozzle 22a
The radial length S connecting the tip of the boss portion 22 and the axis 0 is
The diameter is set not to exceed 1/2 of the outer diameter D of b. That is, when a circle with a radius of 1/2D is drawn with the axis 0 as the center on a plane that passes through the tip of the injection nozzle 22a and is orthogonal to the axis 0, the relationship is such that the tip of the injection nozzle 22a is located within the circle. Ru. By bending the injection nozzle 22a as described above, the vibration material insertion hole 2 formed in advance in the cylinder head 2 according to the outer diameter of the boss portion 22b can be bent.
It becomes possible to press fit the vibe material 22A into the cylinder head 2 from the connection end surface on the intake manifold 7 side of the cylinder head 2 without the injection nozzle 22a getting in the way. Note that exhaust gas is recirculated from the exhaust system path into the main intake passage 5 through the EGR valve, but the configuration of this part is the same as the conventional one, so illustration is omitted.

In the internal combustion engine configured as described above, the intake valve 1
1 is open during the intake stroke, air-fuel mixture is supplied to the combustion chamber 4 from the main intake passage 5, while gas (air or air-fuel mixture) is injected (suctioned) from the sub-intake passage 22.

Due to this gas injection from the auxiliary intake passage 22, the air-fuel mixture sucked into the combustion chamber 4 forms a swirl around the axis of the cylinder 1, increasing the combustion speed. In particular, in the present invention, the length l of the injection nozzle 22a is determined by the inner diameter d.
By making it larger, the force of the swirl generated becomes stronger, and even when performing the same amount of DGR, it is now possible to operate the engine with a much larger air-fuel ratio than before.

The effects of the present invention are schematically shown in FIG. 3 in an operating range equivalent to 40kx/HR or above. In addition, the third
The points shown as double circles in the figure represent the case where the length of the injection nozzle 22a is set to zero (the diameter of the tip opening is simply made smaller). In this way, by making the length of the injection nozzle 22a larger than its inner diameter d, the force of the generated swirl becomes stronger.
This is thought to be because the ink is given sufficient directivity when passing through point a, and this directivity is sufficiently maintained even after being injected from the injection nozzle 22a.

As described above, the present invention has the shape and dimensions of the auxiliary intake passage provided separately from the main intake passage.
The intake swirl can be made sufficiently strong, increasing the limit of lean combustion, which can greatly contribute to purifying exhaust gas and improving fuel efficiency. In addition, by forming the portion of the sub-intake passage inside the cylinder head from a vibrating material, the injection nozzle formed at the downstream end of the vibrating material can be manufactured to the desired shape and dimensions, resulting in good results. It is possible to easily manufacture a sub-intake passage to obtain the desired result.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG. FIG. 3 is a diagram showing the effect of the present invention. 4... Combustion chamber, 5... Main intake passage, 8... Carburetor (fuel supply device), 11... Intake valve, 22-... Sub-intake passage, 2
2A... Vibrator material, 22a... Injection nozzle, 22b
... Boss portion, l... Length of injection nozzle, S... Radial length, d... Inner diameter, D... Outer diameter, 0... Axis center.

Claims (1)

[Claims] 1 A main intake passage connected to a fuel supply device and opened and closed by an intake valve is provided separately from the main intake passage, and gas is supplied to the combustion chamber so as to generate a swirl of intake air in the combustion chamber during the intake stroke. an auxiliary intake passage for injecting
A portion of the auxiliary intake passage formed in the cylinder head is formed by a pipe material press-fitted into the cylinder head to form an injection nozzle with a diameter reduced at the downstream end, and the length of the injection nozzle portion is is at least as large as the inner diameter of the injection nozzle, and the diameter-reduced tip portion is slightly bent toward the combustion chamber to generate a swirl in the combustion chamber, and the inside of the cylinder head of the pipe material is The length in the radial direction between the axis of the boss part buried in the body and the tip of the bent injection nozzle part is equal to or less than 1/2 of the outer diameter of the boss part. Features an internal combustion engine.