JPH0996269A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine which can promote atomization of fuel with sufficient assist capable relating to an injector even in every operating condition. SOLUTION: An internal combustion engine comprises a cylinder 3 burning a mixture, intake pipe 5 introducing air to this cylinder 3, injector 7 supplying fuel to this intake pipe 5 and an exhaust pipe 9 exhausting combustion gas from the cylinder 3, mutually between the exhaust pipe 9 and the injector 7 is connected by an assist communication pipe 11. An end part in a side of the injector 7 of the assist communication pipe 11 is connected in the vicinity of a fuel flow path in the injector 7, also a check valve 14 is provided, in a side of the exhaust pipe 9 of the assist communication pipe 11, and further a solenoid valve 15 is provided in a side of the injector 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine used as a power source, and more particularly to an internal combustion engine of a system in which fuel is supplied to a cylinder by an injector (electronically controlled fuel injection device).

[0002]

2. Description of the Related Art Conventionally, in an internal combustion engine of a system for supplying fuel by using an injector, there have been the following for the purpose of atomizing fuel. That is, as shown in FIG. 7, the injector 87 is attached to the intake pipe 85. Then, the assist communication pipe 91 derived from the upstream side of the throttle valve 86 is connected to the vicinity of the fuel flow path of the injector 87.

In the internal combustion engine 81 according to this conventional example, in the intake stroke, the pressure in the intake pipe 85 is almost equal to the atmospheric pressure on the upstream side of the throttle valve 86, while the pressure in the downstream side of the throttle valve 86 is small. The side has a negative pressure.
Therefore, in the intake stroke, a pressure difference is generated across the throttle valve 86 in the intake pipe 85. As a result, air for assist flows from the assist communication pipe 91 toward the injector 87, and atomization of fuel is promoted.

Another conventional example is disclosed in Japanese Utility Model Publication No. 63-3428. This conventional example is equipped with a supercharger 120 as shown in FIG.
The supercharged air is introduced into the vicinity of the fuel flow path of the injector 107 via the assist communication pipe 111. An electromagnetic valve 115 for controlling the timing of assist is disposed in the middle of the assist communication pipe 111.

In this conventional example, the exhaust side turbine is driven by the exhaust pressure of the exhaust pipe, and the intake side turbine connected to this exhaust side turbine is rotationally driven. Then, the pressurized air passes through the assist communication pipe 111 and the solenoid valve 1
It is transmitted to the injector 107 by the opening operation of 15. This promotes atomization of the fuel.

[0006]

However, in each of the above conventional examples, the following inconveniences have occurred.
First, in the first conventional example, when the throttle valve is open, that is, under high load, the differential pressure in the assist communication pipe becomes small. As a result, the amount of air introduced into the injector is also reduced, which causes the inconvenience that the atomization of fuel cannot be promoted.

Further, the second conventional example has a disadvantage that it cannot be applied to an internal combustion engine that does not have a supercharger because the supercharger is an essential component. It was

Further, when the internal combustion engine has a low rotational speed and a high load, the driving force by the exhaust pressure for driving the supercharger is also small, and the supercharger cannot effectively supercharge air. The amount of air for assist is reduced. As a result, there has been a problem that the atomization of fuel cannot be sufficiently performed.

[0009]

It is an object of the present invention to improve the disadvantages of the conventional example, and in particular, it is possible to sufficiently assist the injector in any operating condition and to promote atomization of fuel. Its purpose is to provide an institution.

[0010]

In order to achieve the above object, in the invention according to claim 1, the internal combustion engine comprises a cylinder in which the air-fuel mixture burns, an intake pipe for introducing air into the cylinder, and An injector for supplying fuel to the intake pipe and an exhaust pipe for exhausting combustion gas from the cylinder are provided.
The exhaust pipe and the injector are connected by an assist communication pipe. Then, the injector-side end of the assist communication pipe is connected to the vicinity of the fuel flow path in the injector, and the check valve is provided on the exhaust pipe side of the assist communication pipe and the solenoid valve is provided on the injector side. ing.

With the above construction, first, in the exhaust stroke of the cylinder, the pressure in the exhaust pipe rises when the exhaust valve opens. Therefore, high-pressure exhaust gas flows into the assist communication pipe connected to the exhaust pipe. And
The high-pressure exhaust gas is stored between the solenoid valve and the check valve arranged in the assist communication pipe.

Then, when the cylinder enters the intake stroke, the above-mentioned solenoid valve is opened, and high-pressure exhaust gas flows to the injector side. Then, this exhaust gas is introduced in the vicinity of the fuel flow path formed at the tip of the injector, and is injected together with the fuel from the tip of the injector to atomize the fuel.

The injected fuel mixes with the intake air flowing through the intake pipe to form a mixture, which is taken into the cylinder from the intake valve. Next, the intake valve is closed, and the air-fuel mixture is ignited by the spark plug, and the air-fuel mixture is burned. Then, a series of these operations is performed for each cycle to continuously operate the internal combustion engine.

The invention according to claim 2 has a structure in which a surge tank is provided between the check valve and the electromagnetic valve of the assist communication pipe, and the other structure is the same as that of the invention according to claim 1.

According to the above-mentioned configuration, the first aspect
In addition to the effects described above, high temperature and high pressure exhaust gas flows into the surge tank. Then, the electromagnetic valve is opened in synchronization with the fuel injection timing by the injector, and a large amount of exhaust gas flows into the injector.

Further, in the invention according to claim 3, the internal combustion engine includes at least two cylinders in which the air-fuel mixture burns, an intake pipe for introducing air into each of the cylinders, and an injector for supplying fuel to the intake pipe. An exhaust pipe for exhausting combustion gas from each cylinder is provided, and the exhaust pipe and the injector are connected by an assist communication pipe. Then, one end of the assist communication pipe is connected to the vicinity of the fuel flow path inside the injector at the fuel injection timing, and the other end is connected to the exhaust pipe at the exhaust timing.

With the above configuration, for example,
It is assumed that one cylinder is in the exhaust stroke and the other cylinder is in the intake stroke. At this time, high-temperature and high-pressure exhaust gas flows from the exhaust pipe connected to one cylinder into the assist communication pipe. Then, since the end portion of the assist communication pipe is connected to the vicinity of the fuel flow path of the injector arranged in the other cylinder, the fuel is atomized by the pressure of the exhaust gas.

Further, in the invention according to claim 4, in the internal combustion engine, the cylinder in which the air-fuel mixture burns, the intake pipe for introducing air into the cylinder, the injector for supplying fuel to the intake pipe, and the combustion from the cylinder An exhaust pipe that exhausts gas and an exhaust circulation communication pipe that connects the exhaust pipe and the intake pipe are provided, and the exhaust circulation communication pipe and the injector are communicated by the assist communication pipe. Then, the injector-side end of the assist communication pipe is connected to the vicinity of the fuel flow path inside the injector.

With the above construction, the exhaust gas of high temperature and high pressure flows into the exhaust circulation communication pipe connected to the exhaust pipe. Then, the negative pressure valve disposed in the middle of the exhaust circulation communication pipe operates, and the other end of the exhaust circulation communication pipe communicates with the intake pipe. Then, at this time, the exhaust gas also flows into the assist communication pipe connected to the downstream side of the negative pressure valve and is introduced into the injector.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. First, as shown in FIG.
Is a cylinder 3 in which the air-fuel mixture burns, an intake pipe 5 for introducing air into the cylinder 3, an injector 7 for supplying fuel to the intake pipe 5, and an exhaust pipe 9 for exhausting combustion gas from the cylinder 3. The exhaust pipe 9 and the injector 7 are connected to each other by an assist communication pipe 11. And
The end portion of the assist communication pipe 11 on the injector 7 side is connected to the vicinity of the fuel flow path inside the injector 7, and the check valve 13 is provided on the exhaust pipe 9 side of the assist communication pipe 11 and the solenoid valve on the injector 7 side. 15 are provided.

Explaining the above in detail, the internal combustion engine 1 is
As shown in FIG. 1, a cylindrical cylinder 3 is provided,
A piston 13 is slidably fitted in the cylinder 3. Further, one end of a connecting rod (not shown) is connected to the piston 13 via a piston pin (not shown), and the other end is connected to a crankshaft (not shown).
It is connected to.

A cylinder head 3a is arranged above the cylinder 3. An intake pipe 5 is arranged on one side of the cylinder head 3a, and an intake valve 16 is arranged at the end of the intake pipe 5 on the cylinder 3 side. The intake valve 16 is for intake of air used for combustion of the internal combustion engine 1. The intake valve 15 is opened and closed by a cam shaft (not shown).

An injector 7 is mounted near the intake valve 16 of the intake pipe 5. The injector 7 supplies fuel into the intake pipe 5 and controls the stop thereof based on a signal from a main controller (not shown). Here, the control of the injector 7 is performed based on the operating state of the internal combustion engine 1.

On the other hand, an exhaust pipe 9 is arranged on the opposite side of the intake valve 16 (on the left side in the figure). This exhaust pipe 9
Is for discharging combustion gas after combustion as exhaust gas. An exhaust valve 17 is arranged at the end of the exhaust pipe 9 on the cylinder 3 side. Like the intake valve 15, the exhaust valve 17 is also opened / closed at a predetermined timing by a camshaft to exhaust combustion gas.

An ignition plug 19 is attached to the center of the cylinder head 3a. This spark plug 19
Is for igniting the air-fuel mixture in the cylinder 3, and its ignition timing is controlled by a main controller (not shown).

Next, the structure for assisting the fuel injection of the injector 7 will be described in detail. First, in FIG. 1, the exhaust pipe 9 and the injector 7 are communicated with each other by an assist communication pipe 11. The assist communication pipe 11 is for introducing the exhaust gas discharged from the cylinder 3 to the exhaust pipe 9, and is made of a metal pipe.

A check valve 14 is arranged near the exhaust pipe 9 side of the assist communication pipe 11. This check valve 14
Is for preventing backflow of the inflowing exhaust gas for assist to the exhaust pipe 9 side. In the present embodiment, the check valve 14 using the ball-shaped member is used, but the present invention is not limited to this, and may be a reed type check valve, for example.

Further, the solenoid valve 1 is provided downstream of the check valve 14.
5 are provided. The solenoid valve 15 is for communicating the assist communication pipe 11 in synchronization with the fuel injection timing of the injector 7, and opens and closes based on a signal from the main controller. That is, the solenoid valve 15 is controlled to be opened during the fuel injection timing and to be closed during the other timings.

The other end of the assist communication pipe 11 is
The injector 7 is connected near the fuel flow path. More specifically, a cylindrical space is formed around the fuel flow path, and the exhaust gas introduced from the assist communication pipe 11 flows into this space.

Next, the internal combustion engine 1 configured as described above
First, in the exhaust stroke after the air-fuel mixture is burned, the exhaust valve 17 is opened and the piston 13 is lifted, and the burned gas is discharged to the exhaust pipe 9.
At this time, in the exhaust stroke, the pressure in the exhaust pipe 9 rises, and the high-temperature and high-pressure exhaust gas flows into the assist communication pipe 11 connected to the exhaust pipe 9 through the check valve. The exhaust gas is stored between the electromagnetic valve 15 and the check valve 14 arranged in the assist communication pipe 11.

Then, when the cylinder 3 enters the intake stroke, the solenoid valve 15 is opened based on the signal from the main control section, and high-pressure exhaust gas flows to the injector 7 side.
Then, this exhaust gas is introduced in the vicinity of the fuel flow path formed at the tip portion of the injector 7, is ejected from the tip portion of the injector 7 together with the fuel, and the fuel is atomized and injected.

The fuel atomized and injected is the intake pipe 5
The mixture is mixed with the intake air flowing inside and becomes a mixture, which is sucked into the cylinder 3 from the suction valve 16. Next, the intake valve 16 is closed, and the air-fuel mixture is ignited by the spark plug 19, and the air-fuel mixture is burned. Then, a series of these operations is performed in each cycle to continuously operate the internal combustion engine 1.

Further, FIG. 2 shows a check valve 34 of the internal combustion engine 21.
The surge tank 22 is disposed between the solenoid valve 27 and the solenoid valve 27. The surge tank 22 is provided to store a large amount of exhaust gas. Here, when combustion in the cylinder 23 is completed, high-temperature and high-pressure exhaust gas flows into the surge tank 22. And
The electromagnetic valve 35 is opened in synchronization with the fuel injection timing by the injector 27, and a larger amount of exhaust gas is injected into the injector 2.
Flow into 7.

FIG. 3 shows that the internal combustion engine 41 has four cylinders 43a, 43b, 43c, 43d and intake pipes 45a, 45b, 45c, 45d for introducing air into the cylinders 43a, 43b, 43c, 43d. And injectors 47a, 47b, 47c, 47d for supplying fuel to the intake pipes 45a, 45b, 45c, 45d, and exhaust pipes 49a, 49b, 49c for exhausting combustion gas from the cylinders 43a, 43b, 43c, 43d. , 49d, and the exhaust pipes 49a, 49b, 49c, 49d and the injectors 47a, 47b, 47c, 47d are connected by the assist communication pipes 51a, 51b, 51c, 51d. Then, the assist communication pipes 51a, 5
One end of 1b, 51c, 51d is connected in the vicinity of the fuel flow path in the injector at the fuel injection timing, and the other end is connected to the exhaust pipe at the exhaust timing.

Here, in the present embodiment, the first exhaust pipe 4
9a and the fourth intake pipe 45d are connected to each other, and the second exhaust pipe 4
9b and the third intake pipe 45c are connected. In addition, the third exhaust pipe 49c and the second intake pipe 45b are connected, and further, the fourth exhaust pipe 49d and the first intake pipe 45a are connected. These combinations are as shown in FIG.
It is determined from the relationship between the exhaust timing of each cylinder and the fuel injection timing. Here, the code [Ex. ]
Indicates the period of the exhaust stroke with respect to the crank angle of each cylinder, and the symbol [Inj. ] Indicates the period of fuel injection with respect to the crank angle of each cylinder.

That is, considering a combination of cylinders in which the exhaust stage and the fuel injection stage overlap at the same time, as shown in FIG. 4, when the fourth cylinder 43d is in the exhaust stroke, the fuel is discharged in the first cylinder 43a. It is the time of injection. These combinations are applied to all the cylinders 43a, 43
By applying b, 43c, and 43d, it becomes possible to assist the injection of fuel without providing a complicated structure, and atomization is promoted.

Further, FIGS. 5 and 6 show a cylinder in which the air-fuel mixture burns and an intake pipe 65 for introducing air into the cylinder.
And an injector 67 for supplying fuel to the intake pipe 65.
And an exhaust pipe 69 for exhausting combustion gas from the cylinder, and an exhaust circulation communication pipe 7 for communicating the exhaust pipe 69 with the intake pipe 65.
0, the case where the exhaust circulation communication pipe 70 and the injector are connected by the assist communication pipe 71 is shown. Further, the end of the assist communication pipe 71 on the injector 67 side is connected to the vicinity of the fuel flow path 72 in the injector.

At the tip of the injector 67, as shown in FIG. 6, the fuel supplied from the main body of the injector reaches the tip of the injector 67. In addition, the fuel flow path 7
A predetermined cylindrical space 74 is formed in the peripheral portion of 2.
The cylindrical space 74 and the fuel flow path 72 are in communication with each other.

The exhaust pipe 6 is constructed as described above.
The exhaust gas of high temperature and high pressure flows into the exhaust circulation communication pipe 70 connected to 9. Then, the negative pressure valve 76 disposed in the middle of the exhaust circulation communication pipe 70 operates, and the exhaust circulation communication pipe 70
The other end of is connected to the intake pipe 65. At this time, the assist communication pipe 71 connected to the downstream side of the negative pressure valve 76.
Also, the exhaust gas flows in and is introduced into the injector 67. Then, the fuel is atomized by the pressure of the exhaust gas supplied from the assist communication pipe 71.

[0040]

Since the present invention is constructed and functions as described above, according to the invention of claim 1, the exhaust pressure of the exhaust pipe is used, so that the conventional mechanism using the differential pressure in the intake pipe is used. In comparison, a large pressure difference can be secured. Therefore, there is an excellent effect that the fuel is sufficiently atomized and the internal combustion engine can be smoothly operated.

Further, since the exhaust gas is used for assist, the fuel is heated by the heat of the exhaust gas, and the vaporization of the fuel is promoted, which is an excellent effect.

Further, according to the invention of claim 2, since the surge tank is provided in the middle of the assist communication pipe, a larger amount of exhaust gas for assist is provided compared with the effect of the invention of claim 1. Can be stored, and the excellent effect of further promoting atomization of the fuel is produced.

According to the third aspect of the present invention, since the exhaust pipe for the exhaust stage and the injector for the fuel injection stage are connected to each other, the pipe of the appropriate assist communication pipe can be used.
Exhaust gas for a sufficient assist can be supplied with a simple structure, and the excellent effect of promoting atomization of fuel is produced.

Further, according to the invention of claim 4, since the assist communication pipe is connected to the exhaust circulation communication pipe, the existing EGR is used.
There is an excellent effect that the atomization of the fuel can be promoted by using the device as it is.

[Brief description of drawings]

FIG. 1 is a partially omitted sectional view showing an embodiment of the present invention.

FIG. 2 is a partially omitted sectional view showing a second embodiment of the present invention.

FIG. 3 is a partially omitted plan view showing a third embodiment of the present invention.

FIG. 4 is a diagram showing a relationship between fuel injection timing and exhaust timing in each cylinder of the internal combustion engine disclosed in FIG.

FIG. 5 is a schematic view showing a fourth embodiment of the present invention,
It is the figure which made the piping of each communication pipe the cross section.

FIG. 6 is a cross-sectional view showing a connection state of the exhaust circulation communication pipe, the assist communication pipe, and the injector disclosed in FIG.

FIG. 7 is a partially omitted cross-sectional view showing a conventional example.

FIG. 8 is a partially omitted cross-sectional view showing another conventional example.

[Explanation of symbols]

 1 Internal Combustion Engine 3 Cylinder 5 Intake Pipe 7 Injector 9 Exhaust Pipe 11 Assist Communication Pipe 13 Check Valve 15 Electromagnetic Valve 22 Surge Tank 70 Exhaust Circulation Communication Pipe

Claims (4)

[Claims] 1. An exhaust pipe comprising: a cylinder in which an air-fuel mixture burns; an intake pipe for introducing air into the cylinder; an injector for supplying fuel to the intake pipe; and an exhaust pipe for exhausting combustion gas from the cylinder. In an internal combustion engine in which a pipe and the injector are communicated with each other by an assist communication pipe, an end of the assist communication pipe on the injector side is connected to a vicinity of a fuel flow path in the injector, and is connected to an exhaust pipe side of the assist communication pipe. An internal combustion engine comprising a check valve and an electromagnetic valve on the injector side. 2. The internal combustion engine according to claim 1, further comprising a surge tank provided between the check valve and the electromagnetic valve of the assist communication pipe. 3. At least two cylinders in which the air-fuel mixture burns, an intake pipe for introducing air into each cylinder, an injector for supplying fuel to the intake pipe, and an exhaust pipe for exhausting combustion gas from each cylinder. An internal combustion engine in which the exhaust pipe and the injector are communicated with each other by an assist communication pipe, wherein one end of the assist communication pipe is connected in the vicinity of a fuel flow path in the injector related to fuel injection timing, and the other end is exhausted. An internal combustion engine characterized by being connected to an exhaust pipe depending on the time of year. 4. A cylinder in which an air-fuel mixture burns, an intake pipe for introducing air into the cylinder, an injector for supplying fuel to the intake pipe, an exhaust pipe for exhausting combustion gas from the cylinder, and an exhaust pipe. An internal combustion engine including an exhaust circulation communication pipe that communicates the intake pipe, wherein the exhaust circulation communication pipe and the injector communicate with each other through an assist communication pipe, wherein an end of the assist communication pipe on the injector side is located near a fuel flow path in the injector. Internal combustion engine characterized by being connected to.