JPS62139920A - Combustion chamber of internal combustion engine - Google Patents

Abstract

PURPOSE:To secure stabilized and quick combustion in an internal combustion engine and to improve the output and the fuel consumption of the engine by forming a communicating hole introducing a flame from an auxiliary combustion chamber to a main combustion chamber on the bank section dividing the main combustion chamber and the auxiliary combustion chamber on the top section of a piston. CONSTITUTION:A main combustion chamber 2 and an auxiliary combustion chamber 3 are divided by a bank section 4 on the top section 1 of a piston. On the bank section 4, the communication hole 14 opened at the lower end of the combustion chamber 3 and communicated to that of the combustion chamber 2 to introduce the flame in the combustion chamber 3 into the combustion chamber 2 is formed. The atomizated fuel spray F1 is injected from the auxiliary exhaust nozzle 11 of a fuel injection nozzle 5. And atomizated fuel spray F2 is also injected from a main exhaust nozzle 13. Stabilized and quick combustion is thus secured improving the output and the fuel combustion of the engine.

Description

[Detailed Description of the Invention] [Industrial Application Field 1] The present invention relates to the combustion chamber of an internal combustion engine, and in particular uses low cetane number and volatile fuel oil such as fuel oil, gasoline, and alcohol. Concerning the combustion chamber of an internal combustion engine.

[Conventional Technique 1 (i)] In general, in engines such as diesel engines that inject fuel oil directly into the combustion chamber for combustion, it is difficult to mix the intake air (compressed air) and the injected fuel oil well. This is a condition for improving combustibility.However, this is limited to fuel oil injected into the combustion chamber of the above engine that has a high cetane number, such as diesel oil.In other words, gasoline, When using low cetane number/volatile fuel oil such as alcohol,
Since the fuel is vaporized and diffused at the same time as it is injected into the combustion chamber, it has been difficult to ignite it by strong ignition from a spark plug or the like in the combustion chamber and generate a mixture with a concentration that can cause flame propagation. Therefore, the fuel injection amount has to be increased, which is not desirable from the viewpoint of fuel efficiency and output. One possible solution to this problem is to throttle the intake air, but this has not been adopted in direct injection engines because throttling the intake air increases pumping loss in the engine.

Therefore, in order to solve the above-mentioned problems, the present applicant has proposed a combustion chamber for an internal combustion engine (Japanese Patent Application No. 1983-10G944).

This proposal, shown in FIG. 7, makes the piston top 1 concave! A main combustion chamber 2 and a sub-combustion chamber 3 which communicate with each other are arranged side by side, and a fuel injection nozzle 4 is provided which faces into each combustion chamber 2.3 and injects fuel oil. A spark plug 15 is provided to ignite the fuel oil, thereby forming a combustion chamber of the internal combustion engine.

[Problems to be Solved by the Invention] The above proposal ignites and burns the air-fuel mixture trapped in the sub-combustion chamber with swirl at light loads, and ignites the flame in the sub-combustion chamber at medium and high zero loads. This allows flame propagation to the air-fuel mixture in the main combustion chamber via the bank part, thereby achieving stable combustion.

However, the existence of the bank portion that attempts to confine volatile fuel oil within the auxiliary combustion chamber slightly slows down the speed of flame inflow into the main combustion chamber, resulting in a reduction in output and fuel efficiency corresponding to this delay. .

Therefore, there has been a need for a combustion chamber for an internal combustion engine that solves this problem and provides combustion characteristics equal to or better than those of a gasoline engine.

['f@Ming's Purpose] The present invention was created to solve the above problems.

The purpose of the present invention is to create a recess in the top of the piston! The main combustion chamber and the sub-combustion chamber are arranged side by side, and by providing a communication hole in the bank part that forms the peripheral side wall of each other to quickly introduce flame from the D1 combustion chamber to the main combustion chamber IX, Low cetane number/volatile fuel oils such as alcohol burn well in all operating load ranges, including when starting the engine! It is to provide two chambers for twisting the internal combustion engine.

[Ill Summary of the Invention] In order to achieve the above-mentioned object, the present invention forms a communication hole for introducing flame from the auxiliary combustion chamber to the main combustion chamber in the bank portion that partitions the main combustion chamber and the auxiliary combustion chamber at the top of the piston. Therefore, by quickly introducing flame into the main combustion chamber through this communication hole, stable and rapid combustion can be achieved, improving output and fuel efficiency in all operating load ranges, including when starting the engine. It is something.

[Example 1] A preferred embodiment of the combustion chamber of the internal combustion engine of the present invention will be described below with reference to the accompanying drawings.

In FIGS. 1 and 2, 1 is the top of the piston, 2 is the main combustion chamber, and 3 is the auxiliary combustion chamber.

As shown in the figure, the main combustion chamber 2 and the sub-combustion chamber 3 are recessed in the piston top 1 and are arranged side by side, and a part of the circumferential side wall that separates them from each other is a bank part 4 formed in an inclined shape. ing. The main combustion chamber 2 and the sub-combustion chamber 3 are each open at the top, and the sub-combustion chamber 3 is recessed shallower than the main combustion chamber 2 with the piston top 1 as a reference plane. It is formed small relative to the volume of the combustion chamber 2. In this embodiment, the horizontal cross sections of the main combustion chamber 2 and the auxiliary combustion chamber 3 are formed, for example, in a circular shape.

Now, the features of the internal combustion engine of the present invention are that it uses low cetane number and volatile fuel oil such as alcohol and gasoline to achieve good combustion during light zero load, and that it can be used in gasoline engines in all operating load ranges. The object of the present invention is to obtain a combustion chamber for an internal combustion engine that can achieve output and fuel efficiency comparable to those of C.

Therefore, the shape of the combustion chamber, the fuel injection nozzle, and the spark plug are related to each other as follows.

As shown in FIG. 3, the fuel injection nozzle 5 has a valve seat 8 on which the throttle portion 6a of the needle valve 6 is seated, at the tip of a nozzle body 7 that accommodates the needle valve 6 so as to be movable up and down. The throttle portion 6 is raised from the valve seat 8 in the axial direction.
A forms a fuel injection chamber 9 that is opened and closed by the valve seat 8.
The auxiliary nozzle 11 is located in the fuel injection chamber, and the main injector L113 is 1m in the fuel injection chamber.
It is made up of words.

The nozzle diameter of the auxiliary nozzle 11 is formed to be extremely smaller than the nozzle diameter of the main nozzle 13, and from the d1 nozzle 11 atomized fuel injection nFs with an extremely small fuel particle diameter is sent, and from the main nozzle 13, main combustion v2 is sent. The fuel mist F2 having a predetermined penetrating force is ejected from the generated swirl S, and the injection nozzle 5 has a needle valve 6.
It is of the Vintalk type, in which the sub nozzle 11 is opened when the lift value is below a predetermined lift value, and the main nozzle 13 is also opened when the lift value is exceeded.

On the other hand 1. The main combustion chamber 2 and the sub-combustion chamber 3 are connected to each other approximately in the upper center of the bank section 4, and the fuel injection nozzle 5 is injected by the fuel injection nozzle 5. A cutout portion 12 that accommodates eight chambers 9 is formed.

In this embodiment, the fuel injection nozzle 5 has its nozzle body 7 accommodated in a cylinder head (not shown), its sub-injection [111] facing substantially medium flame in the sub-combustion chamber 3, and its main nozzle 1
3 faces the inner wall 2a of the main combustion chamber 2 in the forward direction of the snort S. Also, secondary combustion 'i! 3 and near the atomized fuel film nFI from the sub-nozzle 11. An ignition plug 15 is provided with a protrusion 15a positioned therein and protruding into the auxiliary combustion chamber 3.

On the other hand, a communication hole 14 is formed in the bank part 4 from the lower side of the auxiliary combustion chamber 3 and communicates with the lower part of the main combustion chamber 2, allowing the flame in the auxiliary combustion chamber 3 to flow into the main combustion chamber 2. is formed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The operation of an embodiment of a combustion chamber of an internal combustion engine according to the present invention will be explained below based on the accompanying drawings.

When the engine is started in a very low speed range and under light load, the &1 valve 6 of the fuel membrane nozzle 5 shown in FIG. 3 is moved in the lift direction in accordance with the supplied fuel oil pressure. At the same time as this lift, the throttle portion 6a of the side valve 6 moves away from the valve seat 8 and the sub-nozzle port 11 is opened. At this time, the stem portion 16 formed at the tip of the throttle portion 6a is defined to have a length β that forms a throttle period for opening the fuel injection chamber 9 until the needle valve 6 reaches a predetermined lift value. Therefore, as shown in FIGS. 1 and 2, atomized fuel spray Fr is injected into the sub-combustion chamber 3. When the needle valve 6 reaches a lift value exceeding the throttle period, the main injection port 13 is also opened and fuel spray F, 2 is injected into the main combustion chamber 2.

More specifically, as shown in FIGS. 4 and 5, the atomized fuel film 'rA F t in the sub-combustion chamber 3 comes into contact with the high-temperature compressed air in the sub-combustion chamber 3 and is vaporized at time a. The fuel is trapped together with the swirl S, and is generated in a fuel vapor layer E1 with an appropriate concentration. This fuel vapor Ifil Et is quickly combusted by ignition of the spark plug 15. At this time,
The flame generated here passes through the communication hole 14 to the main combustion chamber 2.
flow into the world.

On the other hand, when the &l valve 6 is under medium or high load exceeding a predetermined lift value, the fuel film nF2 is also injected into the main combustion chamber 2, so a part of the spray F2 is injected into the main combustion chamber 2. The fuel film f flows along the inner wall 2a of the main combustion chamber 2 to the downstream side of the swirl S, and the remaining part collides with the inner wall 2a of the main combustion chamber 2, is scattered, is further atomized, and is vaporized by the compressed air in the main combustion chamber 2. be done. At this time, since the outer surface of the fuel membrane is vaporized depending on the type, a properly thick fuel vapor layer E2 is generated in the main combustion chamber 2.

Now, the fuel vapor FFx E 2 in the main combustion chamber 2 is
2. The flame inflow from the communication hole 14 quickly ignites the flame, and as shown in FIG. It propagates upward along the line and completes combustion.

Here, at the time when the flame propagates from the auxiliary combustion chamber 3 to the main combustion chamber 2, the piston is set at the road dead center position as shown in FIG. The lowering leads to the squish area 17 formed between the cylinder head 18 and the piston top 1. That is,
A reverse squish S2 occurs. At this time, since the flame in the main combustion chamber 2 is propagated from below the combustion chamber, the unburned air-fuel mixture being moved is completely combusted. Further, during light load, a small amount of steam in the sub-combustion chamber 3 is guided into the main combustion chamber through the communication hole 14, but it can be combusted by the oxidation catalyst and E a R (exhaust gas reburning weight).

Therefore, the low cetane number/volatile fuel oil can be burnt efficiently and rapidly in all operating load ranges including when starting the engine, thereby improving engine output and fuel efficiency.

[Effects of the Invention] As is clear from the detailed description above, the combustion chamber of the internal combustion engine of the present invention can exhibit the following excellent effects.

(1) In addition to stably burning low cetane number and volatile fuel oils such as alcohol and gasoline, the flame in the auxiliary combustion chamber can be quickly guided into the main combustion chamber, so it can be used under any operating load, including when starting the engine. It is possible to achieve high output and high fuel efficiency in the 19 range.

(2) It is possible to obtain the same fuel efficiency as a diesel engine using light oil as fuel, and it is possible to obtain output performance equivalent to a gasoline engine [11] using gasoline as fuel.

+3+ I-I Exhaust unburnt substances such as Cs aldehyde can be significantly reduced.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a preferred embodiment of a combustion chamber of an internal combustion engine according to the present invention, FIG. 2 is a schematic vertical cross-sectional view of FIG. 1, FIG. 3 is a schematic cross-sectional view of a fuel injection nozzle, and FIG. Figures 6 to 6 are schematic diagrams showing the combustion process, and Figure 7 shows the combustion chamber of a conventional internal combustion engine. i is a schematic diagram. In the figure, 1 is the piston top, 2 is the main combustion chamber, 3 is the sub-combustion chamber, 4 is the bank part, 5 is the fuel injection nozzle, 11 is the sub-mouth,
13 is a main nozzle, 14 is a communication hole, and 15 is a spark plug. Figure 2 Figure 4 Figure 6 Figure 7

Claims (2)

[Claims] (1) A combustion chamber for an internal combustion engine, characterized in that a communication hole for introducing flame from the auxiliary combustion chamber to the main combustion chamber is formed in a bank portion that partitions the main combustion chamber and the auxiliary combustion chamber at the top of the piston. (2) The combustion chamber for an internal combustion engine according to claim 1, wherein the auxiliary combustion chamber is formed shallower than the main combustion chamber, and the communication hole is inclined so as to face the main combustion chamber from the auxiliary combustion chamber.