JPS6245926A - Combustion chamber for double cell type internal combustion engine - Google Patents

Abstract

PURPOSE:To make such fuel oil as being high in volatility ignite into combustion so well, by evaporating the fuel oil with a heating device at the time of low temperature starting, and evaporatively distributing the fuel oil including alcohol, etc., out of a sub-nozzle hole, where preceding injection takes place, to the inside of an auxiliary combustion chamber at the time of engine low load. CONSTITUTION:At the time of low speed and load load in an engine, fuel oil out of a sub-nozzle hole 14 is made to be sprayed and to flow along an inner wall 6a of an auxiliary combustion chamber 6, while it is expanded by a minor swirl S2, and a uniform fuel vapor layer A1 is formed over the auxiliary combustion engine as a whole. And, this fuel vapor layer A1 is suddenly burned by ignition of an igniting device 7, and combustion gas is blown to each inside of a swirl subchamber 2 and a main combustion chamber 4 via a lip part 11, thus combustion is completed. In addition, at the time of medium, high speed and medium, high load, the fuel oil is sprayed out of the sub-nozzle hole 14 and a main nozzle hole 15. And, at the time of severe cold, an on-off switch 17 is turned on, a heating device 16 is operated, heating the inside of the auxiliary combustion chamber 6, and thereby the fuel vapor layer A1 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a pre-chamber internal combustion engine, and particularly to a combustion chamber of a pre-chamber internal combustion engine that can use highly volatile alcohol fuel oil.

[Prior Art] In general, a proposal for a direct injection diesel engine described in Japanese Patent Application Laid-Open No. 1322-1983 is known as an engine that has high thermal efficiency, low fuel r1 consumption rate, and can cope with deterioration of fuel quality. There is.

This proposal is not shown in Fig. 5.
ll! In a direct injection diesel engine in which fuel is injected and supplied from a nozzle 8 and a mixture of the fuel and air is ignited by a spark plug 7a, the fuel injection nozzle 8
are two fuels FNi that inject fuel in different directions.
The spark plug 7a has a guard port 20, 21, and the spark plug 7a has a gap 7b in a region sandwiched between the main streams of fuel injected from the two injection ports 20 and 21, thereby forming a direct injection diesel engine. Was.

[Problems to be Solved by the Invention] The above proposal uses a spark plug and provides the gap between the main streams of fuel injected from two fuel nozzles. The purpose is to ignite the nearby air-fuel mixture (set to a stoichiometric air-fuel ratio) to improve ignitability and combustibility.

However, when the injected fuel is highly volatile alcohol, gasoline, etc., the fuel oil injected into the combustion chamber evaporates in a short time and is evenly distributed throughout the combustion chamber. Therefore, it was difficult to obtain a desired air-fuel ratio of the air-fuel mixture. In other words, since the air-fuel mixture in the combustion chamber becomes diluted overall, the flame propagation after ignition by the spark plug becomes poor and a misfire occurs. Therefore, misfires must be prevented, which leaves the problem of worsening fuel efficiency.

In addition, when starting an engine when the intake air temperature (atmospheric humidity) is low, the fuel, not just volatile fuel oils such as alcohol and gasoline, generally deteriorates as the Y1 decreases during evaporation. It generates smoke from unburned alcohol such as aldehydes, and there is a need to improve low-temperature startability.

[Object of the invention 1 The present invention was created to solve the above problems,
The object of the present invention is to provide a pre-chamber internal combustion engine that can successfully ignite and burn highly volatile fuel oil (gasoline, alcohol) even when the atmospheric temperature and engine cooling water are low, thereby improving low-temperature startability. to provide a combustion chamber.

, [Summary of the Invention] In order to solve the above-mentioned problems, the present invention provides a fuel injection nozzle having a main and a sub-injection port facing the vortex sub-chamber through a spherical auxiliary combustion chamber communicating therewith, When the auxiliary nozzle of the nozzle faces the wall of the auxiliary combustion chamber, an ignition means such as a spark plug and a heating means for creating a high temperature atmosphere in the auxiliary combustion chamber are provided in the auxiliary combustion chamber. During a low-temperature start when the atmospheric temperature is low and the engine cooling water temperature is low, the heating means is heated to evaporate the fuel oil, and during low-load engine operation, fuel oil such as alcohol is injected in advance from the auxiliary nozzle into the auxiliary combustion chamber. The fuel oil is evaporated and distributed, and is rapidly combusted by an ignition means, and during medium to high load operation of the engine, the flame is propagated to the fuel oil with a large penetration force, which is injected from the main nozzle into the vortex subchamber and evaporated there. The aim is to achieve good combustion.

Embodiment A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic longitudinal cross-sectional view of a cylinder head showing a swirl pre-chamber, which is an example of a combustion chamber of a pre-chamber internal combustion engine.

As shown in the figure, a swirl sub-chamber 2 is formed in the cylinder head 1, and a communication passage (throat) 5 is formed below the swirl sub-chamber 2 to connect the swirl sub-chamber 2 and the cylinder chamber 4 of the cylinder body. The communication passage 5 is connected to the inner wall 2 of the auxiliary chamber 2 through which high-pressure air is pumped from the cylinder chamber 4 to the inner wall 2 of the vortex auxiliary chamber 2.
A swirl chamber 5a is formed to generate a swirl S flowing along a.

Now, the features of the combustion chamber of the pre-chamber internal combustion engine of the present invention are that it can ignite highly volatile fuel oil such as alcohol during low-temperature starting, low engine speed, and low engine load, and ensure reliable flame propagation. The aim is to achieve combustion by

Therefore, the auxiliary combustion chamber 6 communicating with the vortex side v2, the ignition means 7 disposed in the auxiliary combustion chamber 6, and the fuel injection nozzle that injects fuel oil in relation to the auxiliary combustion chamber 6 and the vortex auxiliary chamber 2. 8 is constructed as follows.

The main swirl S1 generated therein is introduced above the vortex subchamber 2 shown in FIG.
An auxiliary combustion chamber 6 that generates a minor swirl S2 that rotates in the opposite direction to the combustion chamber 6 is formed in communication with the combustion chamber 6. Specifically, in this embodiment, the inner circumferential surface of the heat shield 10, which is integrally accommodated in a passage 9 opened from one side of the cylinder head 1 above the vortex subchamber 2, is enlarged to have a spherical diameter. An auxiliary combustion chamber 6 is formed therein. The volume of the auxiliary combustion chamber 6 is smaller than that of the vortex sub-chamber 2J, and a lip portion 11 is formed in the communication portion between the vortex sub-chamber 2 and the auxiliary combustion chamber 6.
The main and minor swirls S+ and 82 in each of the auxiliary chambers 2 and auxiliary combustion chambers 6 are constructed so as not to interfere with each other. Furthermore, as shown in the figure, inside the heat shield 10 forming the auxiliary combustion chamber 6, through the inner wall of the heat shield 10, that is, the inner wall surface of the auxiliary combustion chamber 6,
A heating means 16 such as a heat coil is provided to create a high-temperature atmosphere in the auxiliary combustion chamber 6, and this heating means 16 includes:
A power source 18 such as a battery is connected via an open/close switch 17 .

On the other hand, the fuel injection nozzle 8 accommodates one valve 13 in the nozzle body 12 so as to be able to move up and down, and opens the sub-nozzle 14 formed on the auxiliary combustion chamber 6 side of the nozzle body 12 in the initial lift region of the sub-valve 13. At the same time, when the lift area is exceeded, - is formed on the auxiliary combustion chamber 6 side of the nozzle body 12.
1: It is configured to open the nozzle 15, and the nozzle diameter of the main nozzle 15 is set to be larger than the nozzle diameter of the sub nozzle 14.

The fuel injection nozzle 8 of the so-called vintox type configured in this manner is provided so as to face into the swirl sub-chamber 2 via the auxiliary combustion chamber 6 .

Specifically, the sub-injection [114] of the fuel injection nozzle 8 faces the inner wall 6a of the auxiliary combustion chamber 6, and the main injection port 15 faces substantially the center of the swirl sub-chamber 2.

Therefore, the fuel oil injected from the auxiliary nozzle 14 swirls around the inner wall 6a of the auxiliary combustion chamber 6 together with the mybooth swirl S2, and is evaporated at an accelerated rate by the compressed air, so that no air is left in the auxiliary combustion chamber 6. A fuel vapor layer A1 with a high fuel ratio is generated.

In addition, the main fuel oil injected from the main injection port 15 with a large penetration force becomes the injection east F and is supplied into the swirl subchamber 2 while involving much of the fuel vapor layer A1 in the auxiliary combustion chamber 6, Here, a fuel vapor layer Δ2 is formed which is swirled together with the main swirl S1 and vaporized.

In order to efficiently ignite and burn the generated fuel vapor layers A+ and A2, an ignition means 7 such as a glow plug or a spark plug is provided in the auxiliary combustion chamber 6. In the embodiment, a spark plug 7a is employed as shown in FIGS. 1 and 2, and as shown in FIG. 3, a gap 7b of the spark plug 7a protrudes into the auxiliary combustion chamber 6. G-1, which makes it easy to touch the fuel vapor layer A1 and ignite it.

In the description of this embodiment, volatile fuel such as alcohol was used as the fuel, but it goes without saying that light oil can also be used to an equal or greater extent in the combustion chamber of the pre-chamber internal combustion engine of the present invention.

Furthermore, the heating operation of the heating means 16 can be automatically controlled by a control unit (microcomputer) based on an atmospheric temperature sensor, engine cooling 7J/water wetness sensor, rotation speed and load sensor, etc. be.

The operation of the present invention will be explained below based on FIGS. 1 to 4.

When the engine is at low speed and low load, fuel oil is injected from the sub-nozzle 14 as shown in FIG. 3. The injected fuel oil flows along the inner wall 6a of the auxiliary combustion chamber 6, expands as it flows downstream due to the minor swirl S2, and is spread over the entire auxiliary combustion chamber 6.

Moreover, since fuel oil is a highly volatile alcohol, it is rapidly evaporated by the heat of the minor swirl S2 and the wall heat, and a uniform fuel vapor layer A1 is generated throughout the auxiliary combustion chamber 6. Since this fuel vapor layer A1 is regulated by the lip portion 11, the amount of intrusion into the swirl subchamber 2 is kept small.

That is, since the auxiliary combustion chamber 6 is filled with the fuel vapor layer A1 with excellent ignitability, the air-fuel ratio becomes high and the ignition rate is 1,000 Pl.
Rapid combustion occurs due to ignition at t7. The combustion gas is blown out into the vortex sub-chambers 2, 1 combustion chamber (cylinder chamber 4) through the lip portion 11 due to the pressure in the auxiliary combustion chamber 6, thereby completing combustion.

When the engine is operating at medium/high rotation speeds and medium/high mouth load, the fuel is injected from the sub-nozzle 14 to the main nozzle 15 as shown in FIG. At this time, since the fuel part injected from the main combustion port 15 has a large penetration force, it is drawn into the auxiliary combustion chamber 6 and the flow R
generate. A considerable amount of the fuel/steam layer A1 previously injected and generated by this entrained flow R is supplied into the vortex sub-chamber 2 together with the fuel injected from the main inlet 15, and is swirled by the main swirl S1. Therefore, most of the fuel from the sub-nozzles 14 and 15 is supplied into the swirl sub-chamber 2, where a fuel vapor layer A2 that spreads uniformly throughout the swirl sub-chamber 2 is generated by the main swirl heat and wall heat. .

Therefore, the air-fuel ratio in the vortex auxiliary chamber 2 is set to an appropriate value, so that the flame from the ignition combustion of 1 is propagated to the vapor layer of the fuel 11 left in the auxiliary combustion chamber 6, achieving rapid combustion. The combustion gas is blown out to the main combustion chamber through a communication passage (st) 5, where it is again sufficiently mixed with air to complete combustion. In addition, the generation of the entrainment flow R prevents excessive supply and retention of fuel oil from the main and sub-nozzles 14.15 in the auxiliary combustion chamber 6, and miraculously suppresses over-richness. L. Therefore, volatile bamboo fuel oil such as alcohol can be rapidly and reliably combusted in the entire engine load range.

Now, when the ambient temperature is extremely cold, such as when the engine cooling water temperature is -20 DEG C., the opening/closing switch 17 shown in FIG. As a result, the inside of the auxiliary combustion chamber 6 receives sufficient heating to evaporate the fuel injected from the auxiliary nozzle 14 on the wall surface, thereby forming the fuel vapor layer Δ1 shown in FIG. 2 described above.

The cranking rotation speed at the time of cold start is approximately 1100 pp, and the amount of fuel injected from the sub-nozzle 14 is usually about 1.
2 - The amount is set to be increased by 1.5 to 2 times during loading operation. At this time,
Since the injection pressure to avoid the above-mentioned 1 valve 13 from ref 1 to 1 is small, 1
- It does not lead to a lift that opens the jet [ ] 15.

Therefore, when starting at a low temperature, only the sub-nozzle 14 opens and injects the fuel into the heating means 1.
The fuel is vaporized in the auxiliary combustion chamber 6 heated by the combustion chamber 6, achieving stable and rapid combustion.

In this way, when the first explosion is achieved in the auxiliary combustion chamber 6,
Vortex subchamber 2. The wall temperature of the main combustion chamber will also be kept within a single range, and the engine will start up smoothly. In order to improve this blow-up response, after the first explosion, depending on the atmospheric temperature (
For example, the heating means 16 may be heated for 5 minutes.

Moreover, by performing this heating operation, idling operation can be stabilized and combustion efficiency can be improved.

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

(1) Since the heating means can heat the auxiliary combustion chamber at extremely low temperatures, it promotes evaporation of the fuel part and provides stable combustion, improving startability and stabilizing idling.

The generation of unburned alcohol and aldehydes can be suppressed.

+21 Volatile bamboo combustible rice oil such as alcohol, gasoline, etc.
Since combustion can occur without misfires when the engine is operating at low speeds and low loads, combustion efficiency can be improved.

(3) Since alcohol fuel oil can be used, smoke generation during high loads can be eliminated and NOx can be reduced.

(4) Even when using light oil, low-temperature starting fI can be improved, and blue-white smoke and HC can be suppressed.

+5+ 4!4 construction is simple and easy to adopt.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical sectional view showing a preferred embodiment of the combustion chamber of the pre-chamber internal combustion engine of the present invention, FIG. 2 is a cross-sectional view taken along the line T-Tr in FIG. FIG. 4 is a diagram showing the combustion state of the combustion chamber of the pre-chamber internal combustion engine of the present invention, and FIG. 5 is a diagram showing a conventional example. In the figure, 1 is the cylinder head, 2 is the swirl sub-chamber, 6 is the auxiliary combustion chamber, 7 is the ignition means, 8 is the fuel injection Q4 nozzle, 14 is the sub-injection [1, 15 are the main injection ports, 16 is the heating means, S is a swirl, and △ is a fuel vapor layer. Patent application Person: Izuzu Jidosha Co., Ltd. Attorney Sokuju Nobu Kinutani Ml -15= Figure 4

Claims (7)

[Claims] (1) A fuel injection nozzle having a main and auxiliary nozzle is provided in the vortex auxiliary chamber so as to face through a spherical auxiliary combustion chamber communicating with the auxiliary combustion chamber, and the auxiliary nozzle of the nozzle is made to face the wall of the auxiliary combustion chamber. A combustion chamber for a pre-chamber internal combustion engine, characterized in that an ignition means and a heating means for creating a high-temperature atmosphere inside the auxiliary combustion chamber are provided in the auxiliary combustion chamber. (2) The combustion chamber of the auxiliary chamber type internal combustion engine according to claim 1, wherein the auxiliary combustion chamber and the swirl auxiliary chamber communicate with each other via a lip portion. (3) The combustion chamber of the subchamber type internal combustion engine according to claim 1, wherein the auxiliary combustion chamber is formed to have a smaller volume than the swirl subchamber. (4) The combustion chamber of the pre-chamber internal combustion engine according to claim 1, wherein the heating means is comprised of a heat coil. (5) The combustion chamber of the pre-chamber internal combustion engine according to claim 1, wherein the ignition means is comprised of a spark plug. (6) The combustion chamber of the pre-chamber type internal combustion engine according to claim 1, wherein the ignition means comprises a glow plug. (7) The auxiliary chamber internal combustion engine according to claim 1, wherein the fuel injection nozzle has a main and auxiliary nozzle, and the auxiliary nozzle is opened before the main nozzle. combustion chamber.