JP3332719B2 - Combustion chamber of subchamber internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sub chamber injection port applied to a combustion chamber of a sub chamber internal combustion engine.

[0002]

2. Description of the Related Art A first conventional example will be described with reference to FIGS. FIG. 3 is a configuration diagram of a sub-chamber internal combustion engine having a sub-chamber injection port, and FIG. 4 is a cross-sectional view taken along line IV-IV of FIG.

A sub-combustion chamber 2 (hereinafter abbreviated as a sub-chamber) is buried in a cylinder head 4, and the sub-chamber 2 is connected to a cylinder center line A-.
A and is provided near the cylinder liner. The shape of the sub-chamber 2 is hemispherical in the upper part and truncated cone in the lower part. A fuel valve 5 for injecting fuel is installed in the sub-chamber 2 and a glow plug 6 for preheating the sub-chamber when the engine is started is provided as required. is set up.

[0004] The sub-chamber 2 is provided with a main chamber 1 formed by a piston cavity 1 of a piston 7, a cylinder wall 8 and a lower surface of a cylinder head 4 via a sub-chamber injection port 3 provided in a sub-chamber base 9. Hereinafter, the main room is abbreviated).

Next, the operation of the conventional example will be described.
When the piston 7 rises during the compression stroke during engine operation, the main chamber 1
The inside air is compressed and flows into the sub-chamber 2 through the sub-chamber injection port 3 to generate a vortex S. The velocity of the vortex S becomes maximum when the piston 7 approaches the top dead center. Next, when fuel is injected from the fuel valve 5 along the direction of the vortex S, the fuel mixes with the air while swirling in the sub-chamber 2 together with the vortex S to form an air-fuel mixture, and starts igniting from near the glow plug to burn. I do.

The combustion gas and unburned gas in the sub-chamber 2 are
As the pressure difference between the sub-chamber 2 and the lowering movement of the piston 7, the gas is ejected into the main chamber 1 through the sub-chamber injection port 3. The ejected gas works on the piston 7 and mixes with the air in the main chamber 1 at the same time, so that diffusion combustion further proceeds.

In the second conventional example (Japanese Patent Application Laid-Open No. 58-65930), passage areas A ₁ and A ₂ between a main injection port and a sub injection port of a swirl chamber are specified with respect to a sectional area of a cylinder bore. By keeping the ratio within the range, the smoke is reduced, the combustion is improved, and the generation of NOx is suppressed.

Third conventional example (JP-A-57-165623)
The sub-injection opening in the injection direction of the fuel injection valve is formed by a plurality of small-diameter passages, and the heating and vaporization of the fuel supplied to the main chamber is promoted, and the amount of smoke generated Is to be reduced.

A fourth conventional example (Japanese Patent Laid-Open No. 57-165624)
The main chamber-side opening of the main injection port is directed tangentially to the cylinder cylindrical surface, and the main chamber-side opening of the sub injection port is provided near the center of the main chamber. The purpose is to increase the air utilization rate and reduce smoke in a high-load operation range.

[0010]

In order to improve the output fuel efficiency of a sub-chamber internal combustion engine, it is necessary to reduce the throttling loss and heat loss by expanding the sub-chamber orifice. At the same time, it is important to improve the jet flow dispersion characteristics in the main chamber 1. However, if the injection port area is too large, the combustion in the sub-chamber 2 becomes dull, and the ejection energy to the main chamber 1 eventually decreases, the combustion in the main chamber 1 deteriorates, and the fuel consumption, smoke emission and the like become poor.

Therefore, it is important to measure low NOx while suppressing the initial combustion in the sub-chamber 2 to some extent, and to improve fuel efficiency, smoke emission, HC and the like. For this purpose, it is necessary to improve the air utilization rate by dispersing the jets in the main chamber and promote the combustion in the main chamber.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to reduce the NO
An object of the present invention is to provide a combustion chamber of a sub-chamber internal combustion engine capable of improving fuel efficiency, smoke emission and HC at x.

[0013]

The combustion chamber of the sub-chamber internal combustion engine according to the first invention has a sub-chamber for generating a vortex, and includes a sub-chamber injection hole center line of a sub-chamber base buried in the cylinder head. And a side opening from the sub-combustion chamber to the main combustion chamber on the orthogonal plane on both sides of the sub-chamber injection port on a plane perpendicular to a plane including both center lines of the cylinder and the sub-combustion chamber (hereinafter referred to as an orthogonal plane ). provided with a nozzle hole, the angle (theta ₂₎ comprises of the side nozzle holes, or auxiliary combustion chamber bordering the antechamber injection port center line
To the main combustion chamber.
Widening to a range where jet dispersibility of 20 ° or less greatly improves
And further the auxiliary combustion chamber side cross-sectional area of the side injection port and A _2,
It is characterized in that formed tapered toward the main combustion chamber is changed sequentially cross-sectional area A _{1 <A 2} the relationship when the main combustion chamber side cross-sectional area was set to A _1.

The combustion chamber of the sub-chamber internal combustion engine according to the second invention has a sub-chamber for generating a vortex, and is on a plane perpendicular to a plane including both center lines of the cylinder and the sub-combustion chamber, and is provided with a fuel injection valve. vertical section through the center line and the glow plug center line (hereinafter
As parallel to the auxiliary chamber injection port center line perpendicular that cross section) and is positioned, to form the auxiliary chamber injection port subchamber mouthpiece embedded in the cylinder head, on either side of the sub chamber nozzle hole, the opening centerline is the in the orthogonal cross-section, than the following right and left sides 120 ° on the cross section perpendicular toward the main combustion chamber from the auxiliary combustion chamber
Provided with a pair of side nozzle hole which jets dispersibility below were bored by expansion angle in a range of significantly improved, the auxiliary combustion chamber side cross-sectional area of the pair of side injection port and A _2, the main combustion chamber side sectional the area is characterized by formed tapered toward the a _{1 <a 2} becomes the main combustion chamber by sequentially changing the cross-sectional area in relation when the a _1.

[0015]

In the first and second aspects of the present invention, when the piston 7 rises during the compression stroke of the engine, the air in the main chamber 1 is compressed, and the vortex S in the sub chamber 2 passes through the sub chamber injection port 3 and both side injection ports 33.
Is generated. When the piston 7 reaches the top dead center, the vortex velocity becomes maximum. When fuel is injected from the fuel injection valve 5 along the vortex S, the fuel proceeds while mixing with air, and a glow plug provided downstream thereof is provided. Ignition and combustion start from around 6 to the sub indoor wall. At the same time, the pressure in the sub-chamber 2 rises, and the unburned and burned gas is blown into the main chamber 1 through the main injection port and the side injection ports 33.

At this time, most of the jet gas in the sub chamber 2 passes through the main injection port 3, but part of the gas flows through both side injection ports 33. Since both side jets are tapered toward the main chamber 1,
Has become easy to flow out from the auxiliary chamber 2 to the main combustion chamber 1, the minimum aperture is to be governed by the nozzle hole cross-sectional area A ₁ of the main chamber 1 side, the vertical direction (the jet gas in the main chamber 1 does not lower the jet velocity Straight direction),
It is dispersed in the horizontal direction (perpendicular to the straight movement of the jet gas).

Therefore, immediately after jetting from the sub chamber 2 to the main chamber 1, the jet flow dispersibility in the main chamber 1 is greatly improved, the air utilization rate is increased, and combustion is promoted. Further, by optimizing the injection port cross-sectional area ratio A ₁ / A ₂ on the sub-chamber and the main chamber side, significant combustion improvement can be obtained.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view of a combustion chamber of a sub-chamber internal combustion engine, and FIG. 2 is a sectional view taken along line II-II of FIG. FIG. 2 shows a taper-shaped side injection port 33 on both sides of the sub-chamber injection port on a plane perpendicular to a plane including the center line of the sub-chamber injection port 3 and including both center lines of the cylinder and the sub-chamber. the area was auxiliary chamber side and a _2, when the main chamber side was a _1, a _2> a
A side injection port 33 whose sectional area sequentially changes in a relation of ₁ is provided. The other points are the same as the conventional one.

As shown in FIGS. 1 and ₂ , the angle formed by the center lines of the two side jets on the plane including the three center lines of the sub chamber jet and the side jet is θ _2. angle between the plane and the auxiliary chamber bottom containing side nozzle hole center line is theta _1. In FIGS. 1 and 2, the cross-sectional shape of the side nozzle is circular, but other shapes such as an oval and a rhombus may be considered (not shown).

Next, the operation of the above embodiment will be described. When the piston 7 rises during the compression stroke of the engine, the air in the main chamber 1 is compressed, and the sub chamber injection port 3 and the side injection port 33 are compressed.
And flows into the sub-chamber 2 to generate a vortex in the sub-chamber 2. When the velocity of the vortex is maximized near the top dead center of the piston 7 and the fuel is injected from the fuel injection valve 5 along the jet, the fuel proceeds while mixing with air, and flows from the vicinity of the glow plug 6. It ignites and burns over the sub-indoor wall. At the same time, the pressure in the sub-chamber 2 increases, and the unburned and burned gas is jetted into the main chamber 1 through the main injection port 3 and the tapered side injection port 33.

At this time, most of the jet gas in the sub-chamber 2 passes through the main jet port 3, but a part of the gas is jetted into the main chamber 1 through the side jet port 33. Since the jet gas from the side jet port 33 and the main jet gas have an area relationship of (sub-chamber-side jet port cross-sectional area A ₂ )> (main chamber-side jet port cross-sectional area A ₁ ), the jet gas has a jet port flow coefficient as a whole. increases, easily flows out from the subchamber 2 to the main combustion chamber 1, the minimum aperture, the main chamber side nozzle hole cross-sectional area a ₁
, The jet velocity does not decrease as far to the left, and the jet gas is jetted dispersedly in the vertical and horizontal directions of the main chamber 1.

Accordingly, the jet penetration in the main chamber 1 immediately after jetting from the sub-chamber 2 to the main chamber 1 is maintained, the jet flow dispersibility is greatly improved, and the air utilization rate is increased, so that combustion is promoted. You. Further, in order to increase the flow rate coefficient of the injection port to facilitate the outflow, it is possible to further expand the minimum throttle of the side injection port 33. It is necessary to select the optimum angle of performance and exhaust gas for the included angle θ ₂ of both side injection ports 33, but θ ₂ = (120 ° or more at which jet dispersion is greatly improved)
The lower angle range) shows good performance in the experimental results.

In the second embodiment (not shown), both side injection ports are present on a plane perpendicular to the plane including both the center lines of the cylinder and the auxiliary combustion chamber and parallel to the plane including the center line of the auxiliary chamber injection port. Although the operation and effect are similar to those of the first embodiment, the description thereof is omitted.

[0024]

According to the combustion chamber of the present invention, when unburned and burned gas in the sub-chamber is ejected into the main chamber and re-combusted in the main chamber, the front and rear of the main chamber immediately after exiting the main injection port and the side injection port. In addition, mixing with the left and right air is promoted, and the air utilization rate is further improved. In addition, since the area of the side nozzle can be increased, the loss of the nozzle throttle can be reduced.

Therefore, the combustion can be promoted and the combustion period can be shortened, and the equivalent volume of combustion and the combustion efficiency can be improved. That is,
The starting performance is improved, and the output, fuel consumption, smoke emission, HC performance, and exhaust gas characteristics are also improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a combustion chamber of a sub-chamber internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view of a combustion chamber of a conventional sub-chamber internal combustion engine.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main combustion chamber (main chamber), 2 ... sub combustion chamber (sub chamber), 3 ... sub chamber injection port, 4 ... cylinder head, 5 ... fuel injection valve, 6 ... glow plug, 7 ... piston, 8 ... cylinder head , 9 ...
Subchamber base, 10: piston top surface, 33: side injection hole, θ
₁ : sub chamber injection port angle, θ ₂ : included angle of both side injection port center lines, AA: cylinder center line, S: vortex, BB ... sub chamber center line.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-321672 (JP, A) JP-A-57-165623 (JP, A) JP-A-57-165624 (JP, A) JP-A-58-165 65930 (JP, A) JP-A-7-19048 (JP, A) JP-A-55-123311 (JP, A) JP-A-58-75917 (JP, U) JP-A-56-156925 (JP, U) Japanese Utility Model Application Sho 63-141830 (JP, U) Japanese Utility Model Application Hei 1-166719 (JP, U) Japanese Utility Model Application Utility Model 5-38326 (JP, U) Japanese Patent Publication No. 32-3905 (JP, B1) (58) (Int.Cl. ⁷ , DB name) F02B 19/00-19/18

Claims (2)

(57) [Claims] [Claim 1, further comprising a sub-chamber for generating a swirl comprises a sub chamber nozzle hole center line of the auxiliary chamber die embedded in the cylinder head, and a plane containing both the center line of the cylinder and the auxiliary combustion chamber plane perpendicular ( On the orthogonal plane on both sides of the sub chamber injection port ( hereinafter referred to as an orthogonal plane ), side injection ports that open from the sub combustion chamber to the main combustion chamber are provided, and the included angle (θ ₂ ) of the side injection port is determined by the sub chamber. Main fuel from the sub-combustion chamber after the center of the nozzle
120 ° on both left and right sides of the orthogonal plane toward the firing chamber
Angle expansion to greatly improve jet dispersion in the following range
And further the auxiliary combustion chamber side cross-sectional area of the side injection port and A _2,
A combustion chamber of a sub-chamber internal combustion engine, wherein the sectional area is sequentially changed in a relationship of A ₁ <A ₂ when the sectional area on the side of the main combustion chamber is A _1, and is tapered toward the main combustion chamber. 2. A comprises a sub chamber to generate a vortex, perpendicular through the cylinder and the center line and the glow plug center line of the fuel injection valve to a plane perpendicular to the plane containing both the center line of the auxiliary combustion chamber cross section ( as hereinafter referred perpendicular cross-section) in parallel with the auxiliary chamber injection port center line is positioned, to form the auxiliary chamber injection port subchamber mouthpiece embedded in the cylinder head, on either side of the sub chamber nozzle hole, whose opening centerline In the orthogonal cross section, from the auxiliary combustion chamber toward the main combustion chamber, the right and left sides on the orthogonal cross section are 120 °.
Angle expansion to greatly improve jet dispersibility in the following range
In addition to providing a pair of side jet holes drilled and
The auxiliary combustion chamber side cross-sectional area of the pair of side injection port and A _2, the main combustion chamber side cross-sectional area is changed sequentially cross-sectional area A _{1 <A 2} the relationship when the A ₁ tapered toward the main combustion chamber A combustion chamber for a sub-chamber internal combustion engine, wherein the combustion chamber is formed as follows.