JPH0650149A - Vortex chamber type diesel engine - Google Patents

Abstract

PURPOSE:To improve mixing of fuel and air and to improve combustion performance by juxtaposing two swirl chambers in a cylinder head, and providing a means to specify the direction of each injection nozzle for intercommunicating each vortex chamber to a cylinder. CONSTITUTION:Two swirl chambers 2 and 3 are juxtaposed to each other in a cylinder head 1 in a state that outer parts thereof are overlapped with each other, and a communicating part 4 is formed by the overlapped part. Injection nozzles 5 and 8 to respectively intercommunicate the swirl chambers 2, 3 with a cylinder 6 are formed in the rear surface of a cylinder head 7 by which the swirl chambers 2 and 3 are partitioned away from the cylinder 6. The direction of each of the injection nozzles 5 and 8 is set to a direction in which eddy currents opposite to each other are generated by means of the swirl chambers 2 and 3. A fuel injection nozzle 9 through which fuel is injected to the swirl chambers 2 and 3 along the direction of the flow of swirl is disposed to the cylinder head 1. This constitution improves mixing of fuel and air and improves combustion performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swirl chamber type diesel engine.

[0002]

2. Description of the Related Art A swirl chamber type diesel engine has a swirl chamber (pre-combustion chamber) in addition to a main chamber (main combustion chamber) to form a powerful swirl flow in the swirl chamber and to supply fuel to the swirl chamber. By injecting, gas (flame jet) is ejected into the main chamber through the nozzle. This swirl chamber type diesel engine is characterized in that the air-fuel mixture formation is relatively good and the exhaust performance is excellent.

[0003]

By the way, in the conventional swirl chamber type diesel engine described above, the air inflow and the gas injection are performed through the same injection port.
There is a problem that throttling loss occurs at the time of air inflow and the time of gas ejection.

In the related art, in order to improve mixing (mixing) of fuel and air in the swirl chamber, a swirl chamber type diesel engine is provided with an auxiliary injection port separate from the injection port, and the auxiliary injection port is provided in the swirl chamber. A vortex that rotates in a direction is proposed ("Combustion device for engine" (Shokai 56-138115)). However, as in this proposal, if two vortices with opposite rotation directions are generated in one vortex chamber, mutual interference between vortices becomes large, and the expected large mixing effect cannot be obtained.

An object of the present invention is to improve the mixing effect as much as possible in a swirl chamber type diesel engine of a type in which swirl flows in opposite directions are generated in the swirl chamber to improve mixing.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a first swirl chamber and a second swirl chamber, which are arranged side by side in the cylinder head with their outer portions overlapping each other. And a first injection port provided to connect the cylinder and the first swirl chamber on the lower surface of the cylinder head that separates the swirl chamber and the cylinder, and the cylinder and the second swirl on the lower surface. A second jet port provided to communicate with the chamber, and a direction in which the first jet port and the second jet port generate swirls whose rotation directions are opposite to each other in the first swirl chamber and the second swirl chamber. And the cylinder head is provided with fuel injection nozzles for supplying fuel spray from the communicating portion to the first swirl chamber and the second swirl chamber in the flow direction of the swirl, respectively.

[0007]

When the engine enters the compression stroke, the compressed air in the cylinder flows into the first swirl chamber and the second swirl chamber through the first jet port and the second jet port, respectively, as the pressure in the cylinder rises. The compressed air that has flowed into the first swirl chamber through the first jet port generates a swirl in the first swirl chamber, and the compressed air flows from the second jet port to the second swirl port.
The compressed air that has flowed into the swirl chamber generates a swirl flow that is opposite to the swirl flow in the first swirl chamber. As a result, air shearing occurs locally only in the region where these vortices mechanically contact, that is, in the vicinity of the communication part.

At the end of the compression stroke, the first from the fuel injection nozzle
When the fuel spray is injected into the swirl chamber and the second swirl chamber, respectively, the fuel spray injected from these first and second nozzles strengthens the strength of the swirl while compressing the hot compressed air in the swirl. Mix with. The mixture in the vortex is further mixed in the shear region.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 3 show one embodiment of a swirl chamber type diesel engine according to the present invention.

The swirl chamber is composed of a first swirl chamber 2 and a second swirl chamber 3 which are defined by the outer side portions thereof being overlapped with each other so as to be adjacent to each other in the cylinder head 1, and the communicating portion 4 has its first portion. The first swirl chamber 2 and the second swirl chamber 3 are configured to overlap each other.

The first nozzle 5 and the second nozzle 8 are cylinders 6
It is formed in the lower surface portion 7 of the cylinder head 1 that separates the inside from the inside of the first swirl chamber 2 and is formed so as to be opened obliquely upward and tangentially to the first swirl chamber 2 and the second swirl chamber. . Specifically, the first jet port 5 has a counterclockwise first vortex flow V 1 near the right inner peripheral wall of the first vortex flow chamber 2 and in the first vortex flow chamber 2.
And the second injection port 8 is opened in a direction in which
The second vortex chamber 3 is opened toward the left inner peripheral wall and in the second vortex chamber 3 in a direction in which a clockwise second vortex V2 can be generated.

The fuel injection nozzle 9 is provided so as to be located between the first and second swirl chambers 2 and 3 of the cylinder head 1, that is, at the communicating portion 4.

The fuel injection nozzle 9 includes a first injection hole 10 and a second injection hole 10.
And a first injection hole 10 facing the first swirl flow V1 of the first swirl chamber 2 so as to eject the fuel spray, and the second injection hole 11 has a second swirl flow. Its second vortex in chamber 3
It is faced to eject fuel spray in the forward direction of V2.

The diameters of the first injection port 5 and the second injection port 8 are such that there is little throttling loss as a whole of the injection port and the first and second injection ports 8 are the same.
First vortex flow V1 and second vortex flow v2 of appropriate strength in the vortex chambers 2 and 3
The diameters of the first and second injection holes 10 and 11 are determined so that the fuel can be sufficiently atomized, and the first and second swirl chambers 2 and 3 can be atomized. The caliber is determined to be capable of injecting a spray having an appropriate penetration force with respect to the first vortex flow and the second vortex flows V1 and V2.

Further, in the embodiment of the present invention, in order to obtain reliable ignition and combustion, particularly at low temperature (including extremely low temperature) or idling (including low speed and low load), the cylinder The head 1 is provided with a glow plug 12 serving as an ignition means by arranging a heat generating portion in the communication portion 4 thereof.

Next, the operation of this embodiment will be described.

As shown in FIG. 1, when the engine enters the compression stroke, as the pressure in the cylinder 6 rises, the compressed air in the cylinder 6 passes through the first jet port 5 and the second jet port 8 respectively to the first swirl chamber 2 respectively. And into the second swirl chamber 3. The compressed air in the cylinder 6 that has flowed into the first swirl chamber 2 through the first jet port 5 generates a first swirl flow V1 in the first swirl chamber 2 counterclockwise as shown in FIG. The compressed air flowing into the second swirl chamber 3 from 8 generates a second swirl V2 in the clockwise direction. Therefore, local air shearing occurs only in a region where the first vortex flow V1 and the second vortex flow V2 mechanically contact each other, that is, in the vicinity of the communication part 4 as a center.

At the end of the compression stroke, as shown in FIG. 3, fuel spray is injected from the first injection hole 10 and the second injection hole 11 of the fuel injection nozzle 9 into the first swirl chamber 2 and the second swirl chamber 3, respectively. Then, the fuel spray injected from the first injection hole 10 and the second injection hole 11 mixes with the hot compressed air while increasing the strength of the first vortex flow V1 and the second vortex flow V2. Then, of the air-fuel mixture of the first vortex flow chamber 2 and the second vortex flow chamber 3, particularly the air-fuel mixture distributed in the shear region is further advanced in the gasification.

As a result, the premixture having extremely high ignitability and flame spread is distributed in the shear region, and the premixture having lower ignitability and flame spread is distributed outside thereof, and On the outside, these first and second swirl chambers 2,
A fuel film that is vaporized by the ambient temperature of 3 and is used for slow combustion is distributed. Therefore, the flame kernel is surely generated in the shear region of air, and the flame propagates outward with the shear region as the center. Therefore, the combustion occurs relatively rapidly in the shear region and its vicinity, generally slow. Therefore, ignition delay is extremely short, combustion noise is low, and combustion with low smoke is realized.

If the glow plug 12 is heated to obtain reliable ignition and combustion at low temperatures (including extremely low temperatures) and idling (including low speed and low load), the spray upstream It is possible to raise the temperature of the atmosphere in the vortex chamber on the side, and stable ignition and combustion can be obtained even in such a case.

[0022]

In summary, according to the present invention, the following excellent effects are exhibited.

(1) Mixing of fuel and air can be improved as much as possible, and combustion performance can be dramatically improved.

(2) Quiet combustion with extremely low smoke can be achieved.

(3) It is possible to reduce the throttle loss of the injection port.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of a swirl chamber type diesel engine according to the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 2 1st swirl chamber 3 2nd swirl chamber 4 Communication part 5 1st nozzle 6 Cylinder 8 2nd nozzle 9 Fuel injection nozzle

Claims (1)

[Claims] 1. A first swirl chamber and a second swirl chamber which are arranged side by side in the cylinder head so that their outer side portions overlap each other.
A communication portion formed by the overlapping, a first injection port provided to connect the cylinder and the first swirl chamber to a lower surface of the cylinder head that isolates the swirl chamber and the cylinder, and a cylinder to the lower surface. A second jet port provided so as to communicate with the second swirl chamber, and the first swirl chamber and the second swirl chamber are arranged so that swirl flows having mutually opposite rotational directions in the first swirl chamber and the second swirl chamber. A swirl chamber type which is set in a direction in which it is generated, and in which a fuel injection nozzle for supplying fuel spray from the communicating portion to the first swirl chamber and the second swirl chamber in the flow direction of the swirl is provided in the cylinder head. diesel engine.