JPS6045716A - Internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve firing performance and reduce compression ratio by firing and burning a portion of fuel mixture previously filled in an auxiliary combustion chamber in the suction and combustion strokes or previous exhaust one and injecting the remaining fuel into the mixture during combustion or immediately after the combustion. CONSTITUTION:When a portion of required fuel for 1 cycle in the later period of compression or suction is injected into an auxiliary combustion chamber 13 from a fuel injection valve 14 and combustible mixture is filled in said chamber, fuel does not leak into a main chamber 11, but forms the combustible mixture near theoretical mixture in the auxiliary chamber 13. Also, when fuel is injected in the later period of exaust in the previous cycle, time from the injection to ignition is long and fuel is injectd in high temperature gas, so that evaporation of fuel is promoted and radical generation and resolution of fuel are produced. Next, when the compression stroke proceeds and mixture in the auxiliary chamber 13 is fired by an ignition plug 15 prior to the upper dead point, the firing is delayed, but by a short time and does not provide any noise source like Diesel knock. And when during the combustion of mixture or immediately after the combustion, the remaining fuel is injected in the combustible gas, it is immediately fired to begin the combustion without ignition lag.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine having a main combustion chamber and a sub-combustion chamber.

2. Description of the Related Art Conventionally, there is an internal combustion engine such as a diesel engine equipped with a sub-combustion chamber such as a pre-combustion chamber or a swirl chamber, as shown in FIG. To explain this, it has a sub-combustion chamber (sub-chamber) 3 that communicates with a main combustion chamber (main chamber) 1 via a communication hole (nozzle port) 2, and this sub-combustion chamber 3 has a fuel injection valve 4 and a cooling chamber. A glow plug (preheating plug) 5 is provided to heat the atomized fuel and air when the temperature rise due to compression is insufficient during startup. From the fuel injection valve 4, fuel with a high cetane number such as light oil supplied from the fuel supply pump 16 is injected into the compressed and heated in-cylinder high-temperature air whose compression ratio is approximately 20 just before the end of the compression stroke. The fuel is then ignited by self-ignition. Part of the fuel injected into the auxiliary combustion chamber 3 burns, and the pressure therein rises rapidly, pushing high-temperature gas containing unburned or incompletely combusted components into the main combustion chamber 1 at high speed. Continues combustion while promoting flow and mixing with fresh air.

However, in such conventional internal combustion engines,
It takes a considerable amount of time for the fuel injected from the fuel injection valve 4 to come into contact with high-temperature air and rise to a predetermined temperature, mix sufficiently with the air, and start igniting (@fire delay period, generally at a crank angle of 10°). As shown in the characteristic diagram of Figure 2, when the fuel that was continuously injected during the ignition delay period (E in the figure) is then ignited, the pressure in the cylinder increases rapidly.
(B-1C) in the figure, and a noise called so-called diesel knock is generated. Note that F in FIG. 2 indicates the injection period, and G indicates the combustion period. In addition, since this ignition relies on the heat of compression, it requires a very high compression ratio (approximately 20 degrees), and the cylinder block framework is made to be solid, resulting in a heavy engine. Another problem is that only fuels such as light oil with good compression ignitability and a high cetane number can be used.

This invention was made by focusing on such conventional problems, and it is possible to fill a part of the fuel required for one engine cycle into the auxiliary combustion chamber in advance during the engine's intake stroke, compression stroke, or exhaust stroke of the previous cycle. The ignition performance is improved by forming a combustible mixture, combusting it by the ignition means, and injecting the remaining fuel into the combustion gas during this combustion period or immediately after the completion of combustion. The purpose is to solve problems.

The present invention will be explained below based on the drawings.

FIG. 3 is a diagram showing a first embodiment of the present invention.

First, to explain the configuration, it has an auxiliary combustion chamber 13 that communicates with the main combustion chamber 11 via a communication hole 12, and a fuel injection valve 14 and an ignition plug (ignition means) 15 are disposed in this auxiliary combustion chamber 13. .

In the latter half of the compression stroke or suction stroke, as shown in the characteristic diagram of FIG. A combustible mixture is formed and filled in the combustion chamber 13 (
l”a in Fig. 4 indicates the fuel injection period for forming a combustible mixture). At that time, fuel is transferred from the communication hole 12 to the sub-combustion chamber (chamber a1).
Since it is injected against the air flowing into the main combustion chamber (main air) 11, most of the air does not leak into the main combustion chamber (main air) 11, but accumulates in the subchamber 13, and the mixture ratio in the subchamber 13 is close to the stoichiometric mixture. A flammable mixture can be formed.

In addition, if part of the fuel required for one cycle of the engine is injected from the fuel injection valve 14 into the auxiliary chamber 13 during the short period of the exhaust stroke of the previous cycle, the time from the time of fuel injection to the time of ignition is long and the temperature is high. Because it is injected into the burnt gas of the fuel, evaporation of the fuel is promoted, and at the same time, radicals are generated and decomposed (CO and H in methanol, etc.). The compression stroke is further advanced, and a spark discharge is performed with the ignition plug 15 before the top dead center, and the pre-chamber 13
(S in Figure 4 indicates ignition). There is still some ignition delay time from this ignition to ignition, but as shown in the characteristic diagram in Figure 4, the ignition delay (E in Figure 4) is about as short as the ignition delay of a gasoline engine. It's a time thing, and it's not a source of noise like diesel knock. Then, during the combustion period (Ga in Fig. 4) of the above-mentioned air-fuel mixture or immediately after the end of combustion, the remaining fuel is injected into the combustion gas from the fuel injection valve 14 (the remaining fuel is injected into the engine as shown in Fig. 4). [denoted by b), the gas is at a sufficiently high temperature, so there is almost no ignition delay and combustion can be started immediately by ignition (G in Figure 4 does not indicate the combustion period). Therefore, the pressure rise inside the cylinder becomes smooth as shown in Figure 4, and noise caused by ignition delay is prevented.
Moreover, since it does not rely on self-ignition, various fuels with a low cetane number, such as gasoline, can also be used. Furthermore, since it does not rely on compression ignition, the compression ratio can be reduced (for example, to 15 or less) and the force acting on the moving parts is reduced, making it possible to provide an engine that is lightweight due to its IM construction.

When performing continuous fuel injection as in the past, the subchamber 13
Since it is difficult to stably form a combustible mixture within the combustion chamber, ignition may not occur even if ignition occurs during the ignition.However, in this invention, once the fuel injection is stopped (Fa
i Since the auxiliary chamber 13 is sufficiently filled with flammable air-fuel mixture before ignition (S in Figure 4), ignition can occur smoothly, and as a result, the intended purpose can be achieved. (See Figure 4).

Note that injection amount control for the initial part of the fuel injection and the remaining fuel injection can be performed by a cam (not shown) of the fuel supply pump 16, and the ignition power source for the ignition plug 15 is the same as that of a normal gasoline engine. A similar product can be used. Further, since the spark plug 15 is used, a glow plug is not necessary.

FIG. 5 shows a second embodiment of the invention.

In this embodiment, a plasma ignition plug 17 is used in place of a normal spark ignition plug to improve ignition performance. The ignition plug 17 includes a normal ignition circuit 20 that intermittently supplies ignition voltage through the operation of a cam 18 and a cam point 19;
A low voltage power supply circuit 21 is connected in parallel, and 1 to 2
Jyur (j.

Electric energy is applied to the ignition plug 17 once) and a plasma-like flame 22 is emitted from the cavity 23 to the subchamber 1.
3, the ignition delay is shortened. Note that 24 is a center electrode, 25 is a ground electrode, and 26 is a ceramic.

FIG. 6 shows a third embodiment of the invention.

This embodiment includes a first fuel injection valve (first injection valve) 27 that injects fuel for forming an air-fuel mixture and a second fuel injection valve (second injection valve) 28 that injects fuel that serves as an output generation source. These 1st. Second injection valve 27. [8 is arranged in the sub-chamber 13.]

The first injection valve 27 uses the fuel supplied from the first pump 29 to create combustible gas in the subchamber 13, and after igniting it with the ignition plug 15, the second injection valve 27 uses the fuel supplied from the second pump 30.
8 performs the remaining fuel injection.

According to such a configuration, it becomes possible to inject different fuels from the first injection valve 27 and the second injection valve 28 separately. That is, the first injection valve 27 injects gasoline, propane (butane), etc., which has good vaporization properties and is difficult to self-ignite, and is suitable as a fuel for forming an air-fuel mixture, and the second injection valve 28 injects gasoline, propane (butane), etc.
Therefore, it is conceivable to inject light oil, etc., which is suitable as a fuel for generating power, has good ignitability, and is inexpensive. As a result, good ignition performance can be obtained. Note that if the first injection valve 27 is configured to inject near the bottom dead center, it is possible to use a low-pressure pump as the first pump 29.

FIG. 7 shows a fourth embodiment of the invention.

In this embodiment, a sub-intake valve 32 communicating with a fuel supply device 31 is provided in the sub-chamber 13 in place of the first injection valve 27, and the sub-intake valve 32 is opened during the intake stroke to enter the sub-chamber 13. The air-fuel mixture is inhaled. Therefore, an ideal combustible air-fuel mixture can be easily and quickly formed in the auxiliary chamber 13, and ignition by the ignition plug 15 can be performed smoothly.

Other configurations and effects are substantially the same as those of the third embodiment.

FIG. 8 shows a fifth embodiment of the invention.

In this embodiment, there is a risk that the air-fuel mixture in the auxiliary chamber 13 leaks to the main chamber 11 to a certain extent, deteriorating its ignitability, but the communication hole 12 is greatly enlarged to improve fuel efficiency due to throttling loss of the communication hole 12. Therefore, it can be mainly applied to the subchamber 13 of the swirl chamber type.

Note that when using light oil or the like with high self-ignition properties as fuel, the ignition delay period is short even in a normal diesel engine at high speed and high load (especially, even if the ignition means 15 of the present invention is not used, the noise is extremely small. At the time of high speed and high load, the ignition means 15 (17) of each of the above embodiments may be shut off to stop its operation, and the operation of the first injection valve 27<32> may also be stopped.

FIG. 9 shows a sixth embodiment of the present invention.

In the embodiments described above, for example, in the first embodiment, if the injected fuel is configured to always reach the main chamber 1, the fuel injected to form a combustible mixture also leaks into the main chamber 11. In consideration of this, the fuel injection valve 14 is arranged in the auxiliary chamber 13, and the remaining fuel, which becomes the output source, is injected into the burnt gas in the f'J air 13. Configuring. However, since there is almost no oxygen in the burnt gas, the remaining fuel injected later cannot be completely combusted, resulting in the problem of easy generation of soot.

In this sixth embodiment, two nozzles 33 with different injection directions are used.
．． The above-mentioned problems of the above-mentioned embodiment are solved by disposing a P1ntaux type fuel injection valve 35 having 34 holes near the communication hole 12 between the main chamber 11 and the sub-chamber 13. .

As shown in FIG. 10, first and second nozzles 33 are provided at the tip of the fuel injection valve 35. '34 communicates with a fuel supply passage 37 via a control valve body 36. The first nozzle 33 that injects the fuel for forming a combustible mixture is a communication hole (spout).
A second nozzle 34 is disposed facing the auxiliary chamber 13 in contrast to the auxiliary chamber 12 and injects the remaining fuel, which also serves as a source of power generation. It is arranged toward the main chamber 11 from the vicinity of the main chamber 11 side of the communication hole 12 so as to reach the chamber 11 . However, when the second nozzle 34 opens, the first nozzle 33 also opens at the same time, but its injection characteristics are as shown in FIG. will be carried out.

During the compression stroke, the latter half of the intake stroke, or the latter half of the exhaust stroke of the previous cycle, the fuel for forming the ignition mixture is supplied to the first nozzle 33.
The fuel is injected into the auxiliary chamber 13 through the communication hole 12 in the direction of G, and the fuel mixes with the air flowing into the auxiliary chamber 13 during the compression stroke, forming a flammable air-fuel mixture in the auxiliary chamber 13. do. When the air-fuel mixture is ignited by an ignition means such as the spark plug 15, the combustible air-fuel mixture in the auxiliary chamber 13 burns and expands, and high-temperature burnt gas is ejected from the communication hole 12. The remaining fuel is injected from the second nozzle 34 almost simultaneously or immediately after the burnt gas is ejected. In this way, the remaining fuel, which is the source of power generation, is injected into the hot gas, and the initial processes of the fuel, such as fuel vaporization and thermal fuel cracking, proceed quickly, and especially Since the fuel reaches the main chamber 11 where sufficient oxygen is present, the ignition delay is shortened, and the subsequent combustion is completed, suppressing the generation of soot and the like.

FIG. 12 does not show the seventh embodiment of the invention.

This embodiment has substantially the same purpose as the sixth embodiment, but includes first and second fuel injection valves 38 and 39, and the first injection valve injects fuel for forming a combustible mixture. 38 is disposed in the auxiliary chamber 13, and a 21fR injection valve 39 for injecting the remaining fuel, which serves as an output source, is disposed near the communication hole 12 on the main chamber 1 side.

Therefore, the remaining fuel injected from the second injection valve 39 is injected into an atmosphere that is high in temperature and has a sufficient amount of '@ elements, and the desired purpose is achieved. Further, as in the case of the third embodiment, the first injection valve 38 injects gas or gasoline that has good vaporization and is difficult to self-ignite, and the second injection valve 39 injects gasoline that has good ignitability and is inexpensive. It is possible to inject light oil and other quality fuels.

As explained above, according to the present invention, a part of the fuel required for one cycle of the engine is supplied into the auxiliary combustion chamber during the intake stroke, compression stroke, or exhaust stroke of the previous cycle to create a combustible mixture. a first fuel supply means for forming a fuel mixture; an ignition means for igniting and burning the combustible mixture;
A second fuel supply means is provided for injecting the remaining fuel into the combustion gas or through the combustion gas into the main combustion chamber during the combustion period or immediately after the combustion ends, thereby eliminating noise caused by ignition delay. Fuel with a low cetane number can also be used, and effects such as being able to reduce the compression ratio can be obtained.Furthermore, the first fuel supply means and the second fuel supply means can be connected to separate fuel tanks. This makes it possible to separately inject different fuels from the first and second fuel supply means, thereby achieving more appropriate ignition performance.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a conventional device, FIG. 2 is a characteristic diagram of the cylinder pressure versus crank angle of the device shown in FIG. 1, FIG. 3 is a longitudinal sectional view of the first embodiment of the present invention, and FIG. 4 is a characteristic diagram related to the cylinder pressure with respect to the crank angle of the device shown in Fig. 3, and Fig.
The figures are a longitudinal sectional view and a circuit diagram of the second embodiment of the present invention, and the sixth embodiment
The figure is a longitudinal sectional view of the third embodiment of the present invention, FIG. 7 is a longitudinal sectional view of the fourth embodiment of the invention, FIG. 8 is a longitudinal sectional view of the fifth embodiment of the invention, and FIG. 9 is a longitudinal sectional view of the fifth embodiment of the invention. A vertical sectional view of a sixth embodiment of the present invention, FIG. 10 is an enlarged longitudinal sectional view of main parts of the fuel injection valve of FIG.
Fig. 1 is a characteristic diagram regarding the amount of fuel injected with respect to the crank angle of the fuel injection valve shown in Fig. 9, and Fig. 12 is a longitudinal sectional view of the seventh embodiment of the present invention. 11... Main Combustion chamber, 12... Communication hole, 13... Sub-combustion chamber, 14... Fuel injection valve, 15... Ignition plug (ignition means), 16... Fuel supply pump, 17... Plasma Spark plug, 21...Low voltage power supply circuit, 23...Cavity, 27...First fuel injection valve, 28...Second fuel l111 valve, 29...First pump, 30... Second pump, 31...Fuel supply device, 32...Sub-intake valve, 33...First nozzle, 34...Second nozzle, 3
5...Fuel injection valve, 38...First fuel injection valve, 39
...Second fuel 11jl valve. Patent applicant Nissan Motor Co., Ltd.-'1 Figure 2 Figure 4 DC Figure 5 4-7: Figure 6 Figure 7

Claims (1)

[Claims] 1. In an internal combustion engine having an auxiliary combustion chamber communicating with the main combustion chamber through a communication hole, the amount of fuel required for one cycle of the engine is determined during the intake stroke, compression stroke, or exhaust stroke of the previous cycle. a first fuel supply means for supplying a portion of the fuel into the auxiliary combustion chamber to form a mixture; an ignition means for igniting and combusting the mixture; and a first fuel supply means for supplying a portion of the fuel into the sub-combustion chamber; An internal combustion engine comprising: a second fuel supply means for supplying fuel to a main combustion chamber or a sub-combustion chamber. 2. The internal combustion engine according to claim 1, wherein the first and second fuel supply means are one fuel injection device provided in the auxiliary combustion chamber. 3. The first and second fuel supply means are arranged near the communication hole on the auxiliary combustion chamber side, and include a first nozzle that injects fuel into the auxiliary combustion chamber side through the communication hole, and a first nozzle that injects fuel into the auxiliary combustion chamber side through the communication hole. Fountain 9A
′! The internal combustion engine according to claim 1, comprising one fuel injection device having a second nozzle. 4. The first fuel supply means is provided in the intake pipe connected to the auxiliary combustion chamber via the intake valve.
Internal combustion engine as described in section. 5. The internal combustion engine according to any one of claims 1 to 4, wherein the ignition means is a plasma ignition plug. 6. The internal combustion engine according to any one of claims 1 to 5, wherein the ignition means is configured to interrupt ignition in a high speed and high load range of the engine. 7. The internal combustion engine according to any one of the engines, wherein the first and second fuel supply means are any one of the engines. 8. In an internal combustion engine having an auxiliary combustion chamber that communicates with the main combustion chamber through a communication hole, a part of the fuel required for one cycle of the engine is pumped into the auxiliary combustion chamber during the intake stroke, compression stroke, or exhaust stroke of the previous cycle. a first fuel supply means for supplying fuel to the fuel mixture to form an air-fuel mixture; an ignition means for igniting and combusting the air-fuel mixture; 2 fuel supply means are provided, and the first fuel supply means is configured to supply gaseous or highly vaporizable fuel, and the second fuel supply means is configured to supply heavy fuel. Internal combustion engine. 9. The first fuel supply means is a fuel injection device disposed in the auxiliary combustion chamber, and the second fuel supply means is disposed near the communication hole on the main combustion chamber side and injects combustion gas ejected from the communication hole. The internal combustion engine according to claim 8, which is a fuel injection device that injects fuel that reaches the main combustion chamber. 10. Claim 8 or 9, wherein the first fuel supply means is not operated at high speed and high load.
Internal combustion engine as described in section.