JP4231855B2 - Diesel engine vortex chamber combustion chamber - Google Patents

Description

  The present invention relates to a vortex chamber combustion chamber of a diesel engine, and more particularly to a vortex chamber combustion chamber of a diesel engine capable of improving exhaust gas performance.

The configuration of the vortex chamber combustion chamber of the diesel engine on which the present invention is based is as follows.
As shown in FIG. 4 (B), the top dead center direction of the piston (2) in the cylinder (1) is up, the bottom dead center direction is down, the cylinder center axis (3) is reared, and the cylinder peripheral wall (4) In front of the side
Above the cylinder peripheral wall (4), the cylinder head (5) is provided with a head recess (6) that is recessed upward, and a base (7) is fitted into the inlet of the head recess (6), so that the head recess (6) A vortex chamber (8) is formed by the upper half of the vortex chamber (8a) recessed upward in the back and the lower half (8b) of the vortex chamber recessed downward in the base (7), and is formed in the cylinder (1). A main combustion chamber (9) is formed, and a nozzle hole (11) is provided at the rear of the lower base wall (10). The nozzle hole (11) is directed forward from the main combustion chamber (9) toward the vortex chamber (8). The main combustion chamber (9) and the vortex chamber (8) are communicated with each other through the nozzle hole (11), and the nozzle mounting hole (12) in the upper half (8a) of the vortex chamber enters the vortex chamber (8). A vortex chamber combustion chamber of a diesel engine facing the fuel injection nozzle (13).

In this type of vortex chamber combustion chamber, the compressed air in the main combustion chamber is pushed into the vortex chamber (8) from the nozzle (11) in the compression stroke, and becomes a vortex flow (22) along the wall surface of the vortex chamber (8). Fuel is injected into this vortex (22), the fuel particulates ignite, combustion occurs in the vortex chamber (8), and fuel gas and unburned fuel are ejected from the nozzle (11) into the main combustion chamber (9). Combustion occurs in the main combustion chamber (9).
As a prior art of this kind of vortex chamber combustion chamber, there is one disclosed in Japanese Patent Application Laid-Open No. 2004-92579 (Patent Document 1).

  However, in this conventional vortex chamber combustion chamber, at a position behind the fuel injection nozzle as seen from directly below and shifted to the left and right from the axis of the injection nozzle, the flow velocity of the vortex becomes slow, and the exhaust gas performance is reduced. Although it is worse, no special countermeasures have been taken for this, so there is a problem.

JP 2004-92579 A (see FIGS. 1 and 2)

The above prior art has the following problems.
<Problem> There is a limit to improving exhaust gas performance.
At a position where the flow velocity of the vortex flow becomes slow, fuel atomization and mixing with air are insufficient, so incomplete combustion occurs and PM (particulate matter) is likely to be generated. In addition, at the position where the flow velocity of the vortex flow becomes slow, fuel atomization and mixing with air are insufficient, so that ignition delay occurs, a lot of injected fuel burns at a time, the maximum combustion temperature increases, and NO _X Is likely to occur. For these reasons, there is a limit to improving exhaust gas performance.

  An object of the present invention is to provide a swirl chamber combustion chamber of a diesel engine that can solve the above-described problems, that is, a swirl chamber combustion chamber of a diesel engine that can improve exhaust gas performance. .

Invention specific matters of the invention according to claim 1 are as follows.
As illustrated in FIG. 4B, the top dead center direction of the piston (2) in the cylinder (1) is up, the bottom dead center direction is down, the cylinder center axis (3) is rearward, and the cylinder peripheral wall (4 )
Above the cylinder peripheral wall (4), the cylinder head (5) is provided with a head recess (6) that is recessed upward, and a base (7) is fitted into the inlet of the head recess (6), so that the back of the head recess (6) A vortex chamber (8) is formed by the upper half of the vortex chamber (8a) recessed upward and the lower half of the vortex chamber (8b) recessed downward in the base (7). A combustion chamber (9) is formed, and a nozzle hole (11) is provided on the rear side of the lower base wall (10). The nozzle hole (11) rises forward from the main combustion chamber (9) toward the vortex chamber (8). The main combustion chamber (9) and the vortex chamber (8) are communicated with each other through the nozzle hole (11), and fuel is injected into the vortex chamber (8) from the nozzle mounting hole (12) in the upper half of the vortex chamber (8a). In the vortex chamber combustion chamber of a diesel engine facing the injection nozzle (15),
As illustrated in FIG. 1 or FIG. 2, the heat spot member (14) that raises the temperature faster than the wall surface temperature of the vortex chamber (8) by the compression heat in the compression stroke and promotes fuel ignition in the combustion stroke is provided in the vortex chamber. (8)
As illustrated in FIG. 1 (B) or FIG. 2 (B), the vortex is formed at a position rearward of the fuel injection nozzle (15) and shifted left and right from the nozzle axis (13) when viewed from directly below. A pair of left and right heat spot members (14), (14) are attached to the wall surface of the upper half (8a) ,
A vortex chamber combustion chamber of a diesel engine, characterized in that the heat spot member (14) is formed of a material having a higher heat flow rate than the material of the wall surface of the vortex chamber (8) .

(Invention according to Claim 1)
<Effect> The exhaust gas performance can be improved.
As illustrated in FIG. 1 (B) or FIG. 2 (B), a pair of left and right heat spot members (14) (14) (on the wall surface of the upper half (8a) of the vortex chamber at a position where the flow velocity of the vortex (22) becomes slow. Since 14) is attached, the ignition of fuel is promoted by the heat spot members (14) and (14), and the ignition delay is suppressed. For this reason, combustion time becomes long, incomplete combustion is suppressed, and generation | occurrence | production of PM (particulate matter) is suppressed. Further, since the ignition delay is suppressed, the combustion time is lengthened, the maximum combustion temperature is suppressed, and the generation of NO _X is suppressed. For these reasons, exhaust gas performance can be improved.

<< Effect >> The function which improves exhaust gas performance can be improved.
Since the heat spot member (14) is formed of a material having a higher heat flow rate than the material of the wall surface of the vortex chamber (8), the heat transfer rate from the heat spot member (14) into the vortex chamber (8) is large. For this reason, the function of promoting the ignition of fuel is high, and the function of improving the exhaust gas performance can be enhanced.

(Invention according to Claim 2 )
In addition to the effect of the invention according to claim 1 , the following effect is achieved.
<< Effect >> The function which improves exhaust gas performance can be improved.
As illustrated in FIG. 1B, since the heat spot member (14) is disposed at a position avoiding direct hit of the fuel (16) injected from the fuel injection nozzle (15), direct hit of the fuel (16). Therefore, the heat spot member (14) is not cooled, the function of promoting the ignition of the fuel (16) is high, and the function of improving the exhaust gas performance can be enhanced.

(Invention according to claim 3 )
In addition to the effect of the invention according to claim 1 or claim 2 , the following effect is achieved.
<Effect> Engine startability can be improved.
As illustrated in FIG. 1 or FIG. 2, the glow plug is inserted into the vortex chamber (8) from the glow plug mounting hole (19) on the wall of the upper half (8a) of the vortex chamber behind the fuel injection nozzle (15). Since (20) is protruded, the heat of the glow plug (20) is easily transferred to the heat spot member (14) when the engine is started. For this reason, when the engine is started, the startability of the engine can be improved by promoting the ignition of fuel by both the glow plug (20) and the heat spot member (14).

  Embodiments of the present invention will be described with reference to the drawings. FIGS. 1 to 5 are views for explaining a vortex chamber combustion chamber of a diesel engine according to an embodiment of the present invention. In this embodiment, a vortex chamber combustion chamber of a vertical diesel engine will be described.

The outline of the embodiment of the present invention is as follows.
As shown in FIG. 4B, the cylinder head (5) is assembled to the upper part of the cylinder block (23). A cylinder (24) is provided in the cylinder block (23). Cylinder peripheral wall (4) with piston (2) in cylinder (1) facing upward, top dead center direction downward, cylinder center axis (3) close, cylinder peripheral wall (4) close Is provided with a head recess (6) that is recessed upward in the cylinder head (5), and a base (7) is fitted into the inlet of the head recess (6). A vortex chamber (8) is formed by the upper half (8a) of the vortex chamber recessed upward in the back of the head recess (6) and the lower half (8b) of the vortex chamber recessed downward in the base (7). The main combustion chamber (9) is formed in the cylinder (1), and the nozzle hole (11) is provided at the rear of the lower base wall (10). The nozzle (11) is inclined upward and forward from the main combustion chamber (9) toward the vortex chamber (8), and the main combustion chamber (9) and the vortex chamber (8) are communicated with each other through the nozzle (11). The fuel injection nozzle (15) faces the vortex chamber (8) from the nozzle mounting hole (12) in the upper half (8a) of the vortex chamber.

The device for promoting the ignition of fuel in the vortex chamber is as follows.
As shown in FIGS. 1 and 2, the heat spot member (14) that raises the temperature faster than the wall surface temperature of the vortex chamber (8) by the compression heat of the compression stroke and promotes fuel ignition in the combustion stroke is changed to the vortex chamber (14). 8) As shown in FIG. 1 (B) and FIG. 2 (B), when it is installed in the interior, it is rearward of the fuel injection nozzle (15) as viewed from directly below and from the nozzle axis (13) to the left and right. At the shifted position, the heat spot members (14), (14) which are paired on the left and right are attached to the wall surface of the upper half (8a) of the vortex chamber. The heat spot member (14) is formed of a material having a larger heat flow rate than the material of the wall surface of the vortex chamber (8). Specifically, the wall of the upper half of the vortex chamber (8a) is cast iron, which is the material of the cylinder head (5), and the wall of the lower half of the vortex chamber (8b) is the ferrous metering alloy, which is the material of the base (7). The steel and heat spot member (14) is copper.

As shown in FIG. 1A, the heat spot member (14) is disposed at a position avoiding direct hit of the fuel (16) injected from the fuel injection nozzle (15). Further, behind the fuel injection nozzle (15), the glow plug (20) protrudes into the vortex chamber (8) from the glow plug mounting hole (19) on the wall surface of the upper half of the vortex chamber (8a).

The structure of the nozzle is as follows.
As shown in FIGS. 3A to 3D, the nozzle hole (11) is composed of a main nozzle hole (17) and a pair of left and right side grooves (18) and (18), and each side groove (18) is formed as a main nozzle hole. It communicates with the main nozzle hole (17) on the peripheral side of (17). As shown in FIG. 3A, when the base (7) is viewed from the side in a direction perpendicular to the axis (17a) of the main nozzle hole (17), the axis (18a) of each side groove (18) is the main axis. The side grooves (18) are arranged so as to be behind the axis (17a) of the nozzle hole (17), and the elevation angle of the axis (18a) of each side groove (18) with respect to the base lower surface (7a) is the main nozzle hole. Each side groove (18) is oriented so as to be smaller than the elevation angle of the axis (17a) of (17). The elevation angle of the axis (17a) of the main nozzle (17) is 45 °. The axis (13) of the nozzle hole (11) and the axis (17a) of the main nozzle hole (17) substantially overlap.

  As shown in FIGS. 3 (B) to 3 (D), the distance between the axis lines (18a) and (18a) of the pair of left and right side grooves (18) and (18) is gradually reduced toward the front. Each side groove (18) is oriented. As shown in FIGS. 3 (B) to 3 (D), the passage cross-sectional area of each side groove (18) is gradually reduced toward the front. As shown in FIGS. 1 (B), 2 (A), and 2 (B), the compressed air that has passed through the main nozzle (17) in the compression stroke is a central vortex that swirls in the horizontal center of the vortex chamber (8). The compressed air that has passed through the side groove (18) becomes the left and right vortex flows (25) and (25) that swirl on the left and right sides of the vortex chamber (8). The left and right vortex flows (25) and (25) are deflected left and right, disturbing the air on both the left and right sides of the vortex chamber (8), and increasing the air utilization rate. As shown in FIGS. 1 (B) and 2 (B), when viewed from directly below, the position is rearward of the fuel injection nozzle (15) and shifted to the right and left from the axis (13) of the injection port (11). Since the flow speeds of both the central vortex (22) and the left and right vortices (25) and (25) are slow, the heat spot members (14) and (14) are attached thereto.

The shape of the heat spot member and its mounting structure are as follows.
FIG. 5 (A) shows the basic shape used in the above embodiment, which is cylindrical and press-fitted into a heat spot member mounting hole (26) whose base end is opened in the wall of the upper half of the vortex chamber (8a). It is attached. The first modified example shown in FIG. 5 (B) has a disk part (27) provided at the tip of the basic mold, and the base end part is opened on the wall surface of the upper half part (8a) of the vortex chamber. The spot member mounting hole 26 is press-fitted and attached. The second modified example shown in FIG. 5 (C) is provided with a conical truncated cone part (28) at the tip of the basic mold, and the base end part on the wall of the upper half of the vortex chamber (8a). It is press-fitted and attached to the opened heat spot member attachment hole (26). Each of these heat spot members (14) has a ridge (29) formed at the tip, and heat tends to accumulate on the ridge (29) and its peripheral portion, faster than the wall surface of the vortex chamber (8). Raise the temperature.

It is a figure explaining the vortex chamber used with the vortex chamber type combustion chamber which concerns on embodiment of this invention, FIG. 1 (A) is a vertical side view, FIG.1 (B) is BB sectional drawing of FIG. 1 (A). It is. 2A and 2B are views for explaining a vortex chamber of a vortex chamber combustion chamber according to an embodiment of the present invention, in which FIG. 2A is a cross-sectional view taken along the line II-II of FIG. 1A, and FIG. It is a BB line sectional view of). FIG. 3A is a longitudinal side view of the nozzle, FIG. 3B is a schematic perspective view of the nozzle, and FIG. 3C is a diagram illustrating the nozzle of the nozzle used in the vortex chamber of FIG. ) Is a schematic diagram of the nozzle hole viewed in the C direction, and FIG. 3D is a schematic diagram of the nozzle hole viewed from directly below. FIG. 4A is a cross-sectional plan view of a cylinder in which a piston is fitted, and FIG. 4B is a vortex chamber combustion chamber and its peripheral portion. FIG. FIG. 5A is a perspective view of a basic example, FIG. 5B is a perspective view of a first modified example, and FIG. 5B is a diagram illustrating a heat spot member used in a vortex chamber combustion chamber according to an embodiment of the present invention. FIG. 5C is a perspective view of a second modified example.

Explanation of symbols

(1) Cylinder (2) Piston (3) Cylinder center axis (4) Cylinder peripheral wall (5) Cylinder head (6) Recess (6a) Recess (7) Base (7a) Bottom of base (8) Vortex chamber (8a) Vortex Upper chamber half (8b) Vortex chamber lower half (9) Main combustion chamber (10) Base lower wall (11) Port (12) Nozzle mounting hole (13) Port axis (14) Heat spot member (15) Fuel injection Nozzle (16) Fuel (19) Glow plug mounting hole (20) Glow plug

Claims (3)

With the top dead center direction of the piston (2) in the cylinder (1) up, the bottom dead center direction down, the cylinder center axis (3) side rear, the cylinder peripheral wall (4) side front,
Above the cylinder peripheral wall (4), the cylinder head (5) is provided with a head recess (6) that is recessed upward, and a base (7) is fitted into the inlet of the head recess (6), so that the head recess (6) A vortex chamber (8) is formed by the upper half of the vortex chamber (8a) recessed upward in the back and the lower half (8b) of the vortex chamber recessed downward in the base (7), and is formed in the cylinder (1). A main combustion chamber (9) is formed, and a nozzle hole (11) is provided at the rear of the lower base wall (10). The nozzle hole (11) is directed forward from the main combustion chamber (9) toward the vortex chamber (8). The main combustion chamber (9) and the vortex chamber (8) are communicated with each other through the nozzle hole (11), and the nozzle mounting hole (12) in the upper half (8a) of the vortex chamber enters the vortex chamber (8). In the vortex chamber combustion chamber of a diesel engine facing the fuel injection nozzle (15),
In providing the heat spot member (14) in the vortex chamber (8) for raising the temperature faster than the wall temperature of the vortex chamber (8) by the compression heat of the compression stroke and promoting fuel ignition in the combustion stroke,
A heat spot that is paired on the left and right sides of the wall of the upper half (8a) of the vortex chamber at a position that is rearward of the fuel injection nozzle (15) and shifted from the nozzle axis (13) to the left and right when viewed from directly below. Attach members (14) and (14) ,
A vortex chamber combustion chamber of a diesel engine, characterized in that the heat spot member (14) is formed of a material having a higher heat flow rate than the material of the wall surface of the vortex chamber (8). In the swirl chamber combustion chamber of the diesel engine according to claim 1 ,
A vortex chamber combustion chamber of a diesel engine, characterized in that the heat spot member (14) is disposed at a position avoiding direct hit of the fuel (16) injected from the fuel injection nozzle (15). In the vortex chamber combustion chamber of the diesel engine according to claim 1 or 2 ,
The glow plug (20) protrudes into the vortex chamber (8) from the glow plug mounting hole (19) on the wall surface of the vortex chamber upper half (8a) behind the fuel injection nozzle (15). A vortex chamber combustion chamber of a diesel engine.

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