JPS6316123A - Internal combustion engine - Google Patents

Abstract

PURPOSE:To obtain the superior combustion even in case of low load or high load by forming an injection port for the injection into a main combustion chamber in two directions opposed to the normal flow of a swirl and the counterflow of the swirl and making the diameter of the injection port on the normal flow side of the swirl smaller than that on other sides. CONSTITUTION:A fuel injection valve 8 is installed into an ignition chamber 10 opened through a cut part 11 with respect to a main combustion chamber 7 consisting of the recessed spherical part at the top part of a piston 1 and the undersurface of a cylinder head 2. An injection port is formed at the top edge of the fuel injection valve 8 so that two directions of the jetted fuel mist F1 opposed to the normal flow of a swirl S and the jetted fuel mist F2 opposed to the counterflow of the swirl S can be obtained. Further, also the diameter of the injection port is made smaller on the normal flow side of the swirl than that on other sides. Therefore, the increase of the max output and reduction of the min fuel consumption can be obtained, developing the advantages of the ignition stability and the superior exhaust emission in the case when fuel is jetted in the counterflow direction of the swirl.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention mainly relates to a stratified air supply type reciprocating internal combustion engine, and more specifically, to a main combustion chamber that provides good combustion even under low load and high load. The invention relates to an internal combustion engine having a

[Prior art]

In a stratified air supply type reciprocating internal combustion engine with a main combustion chamber formed at the top of the piston, as shown in the conventional example in Fig. 4,
When two fuel sprays from the fuel injection valve 8 are injected into the main combustion chamber 7 provided at the top of the piston as shown by the arrow F, these two fuel sprays F are injected into the main combustion chamber 7 by the air swirl flow. When injecting along the forward flow of a certain swirl S, the minimum fuel consumption and maximum output of the internal combustion engine are good, but there is a problem that low-load combustion stability and exhaust emissions deteriorate.

On the other hand, as shown in the conventional example shown in Fig. 5, when the fuel spray F is sprayed against the forward flow of the swirl S, that is, in the case of swirl backflow injection, a good air-fuel mixture is not formed even in the case of small amount injection. , ignition is stabilized, unburned fuel in exhaust emissions is reduced, low-load combustion is improved, and good combustion performance is obtained, but in this case, the air utilization rate decreases at high power, so There is a problem that the minimum fuel consumption is deteriorated.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned conventional problems, and has the advantages of ignition stability and good exhaust emissions when fuel spray is injected in a direction opposite to the swirl in the main combustion chamber. The purpose of this invention is to provide an internal combustion engine that can increase maximum output and reduce minimum fuel consumption.

[Structure of the invention]

In order to achieve the above object, the internal combustion engine of the present invention has nozzles for injecting fuel spray into the main combustion chamber formed at the top of the piston in two directions opposite to the swirl forward flow and the swirl reverse flow, and also in the swirl forward flow. It is constructed by making the opposing nozzle diameter smaller than the nozzle diameter in the other direction.

〔Example〕

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a plan view showing a cross section of a main part of a combustion chamber of an internal combustion engine in an embodiment of the present invention, and FIG. FIG. 3 is a cross-sectional view of the fir tree in the n direction, and a plan view of the main part showing the swirl inside the main combustion chamber of FIG. 1.

First, as shown in Figs. 1 and 2, the combustion chamber of this internal combustion engine consists of a concave spherical part with a radius R at the top of a piston 10 that reciprocates up and down within the cylinder, and a main combustion chamber consisting of a bottom surface of the cylinder head 2. A fuel injection valve 8 and a spark plug 9 are provided in an ignition chamber 10 which forms a chamber 7 and is open to the main combustion chamber 7 through a notch 11 .

In addition, air is introduced into this combustion chamber through an intake port 5 having an intake valve 6 to generate an air swirling flow as shown by arrow S, that is, a swirl forward flow, so that the fuel flows into the main combustion chamber 7. The spray F is injected and ignited, and the exhaust gas after combustion is discharged from an exhaust boat 3 having an exhaust valve 4.

Therefore, two nozzle ports 8A, 8B are provided at the tip of the fuel injection valve 8, and these nozzle ports 8A, 8. B injected into the main combustion chamber 7 through the ignition chamber 10, respectively. F2
As shown in FIG.
Each nozzle 8A, 8B is formed in two directions so as to have two directions.

Furthermore, in the two nozzles 8A and 8B, the nozzle 8A
The nozzle diameter of the nozzle 8B is smaller than that of the nozzle 8B.

That is, for example, if the diameter of each nozzle port for fuel injection iF in each of the conventional examples shown in FIGS. 4 and 5 is 0.4 mm, the diameter of the nozzle port 8A in the case of the present invention shown in FIG. 8
The nozzle diameter of B is 0.45 mm.

In the internal combustion engine having the combustion chamber according to the embodiment of the present invention shown in FIG. 1 and the conventional combustion chamber shown in FIGS. 4 and 5 described above, the net average effective pressure and the total carbonization The relationship between hydrogen (THC), that is, the state of exhaust emissions, combustion stability, and fuel consumption rate, is shown in each diagram in FIG. 6. The case of the present invention in FIG. The case of the conventional example in the figure is shown by a solid line B, and the case of the conventional example in FIG. 5 is shown by a broken line C, respectively.

As can be seen from these diagrams, the internal combustion engine employing the present invention has good combustion under both low and high loads.

〔Effect of the invention〕

As explained above, in the internal combustion engine of the present invention, it is possible to increase the maximum output and reduce the minimum fuel consumption while taking advantage of the ignition stability and good exhaust emissions when fuel is injected in a direction opposite to the swirl. There is an advantage.

That is, the present invention has the effect that good combustion stability, exhaust emissions, and thermal efficiency can be obtained in the entire operating range over a wide rotational speed and load range.

The present invention can be effectively applied mainly to a stratified air supply type reciprocating internal combustion engine having an ignition chamber.
In this case, it is applicable to both single-cylinder and multi-cylinder cases.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a main part of a combustion chamber of an internal combustion engine according to an embodiment of the present invention, FIG. 2 is a vertical sectional view taken along the direction ■-■ of FIG. 4 and 5 are plan views of main parts showing swirls in the main combustion chamber of different conventional internal combustion engines, and FIG. 6 is a plan view of main parts showing swirls in the main combustion chambers of different conventional internal combustion engines. FIG. 5 is a diagram comparing the net average effective pressure of the internal combustion engine and each combustion effect in the example of FIG. DESCRIPTION OF SYMBOLS 1...Piston, 7...Main combustion chamber, 8...Fuel injection valve, 8A, 8B...Nozzle port, Fl, F2...Fuel spray, S...Swirl.

Claims (1)

[Claims] The nozzles that inject the fuel spray into the main combustion chamber formed at the top of the piston are formed in two directions, each facing the forward swirl flow and the reverse swirl flow, and the diameter of the nozzle facing the forward swirl flow is smaller than the nozzle diameter in the other direction. Internal combustion engine.