JP7075336B2 - diesel engine - Google Patents

Description

The present invention relates to a diesel engine, and more particularly to a diesel engine capable of downsizing the engine.

Conventionally, as a diesel engine, there is a direct injection diesel engine provided with a common rail system (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2014-20278 (see FIG. 1)

In Patent Document 1, if the bore diameter of the cylinder is reduced, combustion deteriorates, and problems such as noise, fuel consumption, and smoke concentration deteriorate, so that the engine cannot be miniaturized.

An object of the present invention is to provide a diesel engine capable of downsizing the engine.

The main configurations of the present invention are as follows.
As illustrated in FIG. 1 (A), the combustion chamber (2) in the cylinder (1), the fuel injection chamber (4) in the cylinder head (3), the combustion chamber (2), and the fuel injection chamber (4). ), The fuel injector (6) facing the fuel injection chamber (4), and the electronic control that controls the injection timing and injection amount of the fuel (5) injected from the fuel injector (6). Equipped with device (8)
As illustrated in FIGS. 2A and 2B, the fuel injection chamber (4) includes a compressed air guide plate (40) extending from the communication port (9) side to the back side of the fuel injection chamber (4) .
As illustrated in FIGS. 2 (A) and 2 (B), the communication port (9) is configured to introduce compressed air that becomes a swirling flow in the vortex chamber (4 at), and is configured in FIG. 2 (A). As illustrated in B), when viewed in a direction parallel to the cylinder center axis (1c), the direction orthogonal to the communication port center axis (1c) is the lateral direction, and the fuel injector (6) is on the lateral center side. The central fuel injection hole (6a) is provided, and the central fuel injection axis (6ac) of the central fuel injection hole (6a) and the central fuel (5a) injected from the central fuel injection hole (6a) are in the vortex chamber (4at). It is oriented so as to pass through the center of the lateral direction and the communication port (9) in order toward the main combustion chamber (2a).
As illustrated in FIG. 2B, a pair of compressed air guide plates (40) are provided on both lateral sides of the lateral central portion of the fuel injection chamber (4), and are substantially the same as the communication port central axis (9c). A compressed air guide gap (41) is formed between the pair of compressed air guide plates (40) and (40), and the gap on the communication port (9) side of the compressed air guide gap (41) is formed. A diesel engine characterized in that the width dimension of the inlet (41a) is set larger than the maximum width dimension of the communication port (2).

<< Effect 1 >> The engine can be downsized.
As illustrated in FIG. 1 (A), in the present invention, the injection of the fuel (5) is electronically controlled, and the compressed air (10) and the fuel pushed into the vortex chamber (4 at) from the communication port (9) in the compression stroke. By adjusting the premix of the fuel (5) injected from the injector (6), combustion in the combustion chamber (2) is optimized, and even if the bore diameter of the cylinder (1) is reduced, noise, fuel consumption, and smoke The concentration can be maintained well and the engine can be miniaturized.

<< Effect 2 >> Premixing of fuel (5) and compressed air (10) in the vortex chamber (4 at) is promoted.
As illustrated in FIGS. 1 (D), FIGS. 2 (A) and 2 (B) show the direction perpendicular to the communication port center axis (1c) when viewed in a direction parallel to the cylinder center axis (1c). As an example, the compressed air (10) that tries to diffuse laterally from the central portion of the vortex chamber (4 at) to both sides in the lateral direction is guided by the compressed air guide plate (40) to the central portion of the vortex chamber (4 at) . The speed of the compressed air (10) is maintained at a high speed, and the premixing of the compressed air (10) and the fuel (5) in the vortex chamber (4 at) is promoted.

In the figure explaining the diesel engine which concerns on embodiment of this invention, FIG. 1A is a block diagram explaining the signal and fuel flow of this engine, and FIG. 1B is used in the engine of FIG. 1A. A perspective view of the communication port, FIG. 1 (C) is a side view of the communication port, FIG. 1 (D) is a plan view of the communication port, and FIG. 1 (E) is an arrow view in the E direction of FIG. 1 (B). It is a figure explaining the auxiliary combustion chamber of the diesel engine which concerns on embodiment of this invention, FIG. 2A is a vertical sectional side view, and FIG. 2B is a sectional view taken along line BB of FIG. 2A. .. FIG. 2A is a cross-sectional view taken along the line III-III of FIG. 2A. It is a figure explaining the combustion chamber of the diesel engine which concerns on embodiment of this invention, FIG. 1A is a plan view of the main combustion chamber, and FIG. be. It is a vertical sectional front view of the diesel engine which concerns on embodiment of this invention. It is a vertical sectional side view of the engine of FIG. It is a front view of the engine of FIG.

1 to 7 are views for explaining a diesel engine according to an embodiment of the present invention, and in this embodiment, a water-cooled in-line 2-cylinder electronic fuel injection type diesel engine will be described.

In this engine, the erection direction of the crank shaft (15) shown in FIG. 6 will be described as the front-rear direction, and the horizontal direction orthogonal to the front-rear direction will be described as the left-right direction.

As shown in FIGS. 5 to 7, this engine is assembled on the cylinder block (16), the cylinder head (3) assembled on the upper part of the cylinder block (16), and the upper part of the cylinder head (3). The cylinder head cover (17), the water pump (18) and the oil pump (19) attached to the front part of the cylinder block (16) shown in FIG. 6, and the engine cooling attached to the front part of the water pump (18). At the bottom of the fan (20), the radiator (21) located in front of the engine cooling fan (20), the flywheel (22) located at the rear of the cylinder block (16), and the bottom of the cylinder block (16). It is equipped with an assembled oil pan (23).
This engine includes an intake device, an exhaust device, a combustion device, an electronic control device, and an engine water cooling device.

The intake device includes an intake manifold (24) shown in FIG. 5 and an air cleaner (not shown) connected to the intake upstream side of the intake manifold (24).
The exhaust device includes an exhaust manifold (25) shown in FIG. 5 and an exhaust treatment device (not shown) connected to the exhaust downstream side of the exhaust manifold (25).
The intake manifold (24) is arranged on the left and right sides of the cylinder head (3), and the exhaust manifold (25) is arranged on the left and right sides of the cylinder head (3).

As shown in FIG. 1 (A), the combustion chamber (2) in the cylinder (1), the fuel injection chamber (4) in the cylinder head (3), the combustion chamber (2), and the fuel injection chamber (4). An electronic control device that controls the injection timing and injection amount of the fuel injector (6) facing the fuel injection chamber (4) and the fuel (5) injected from the fuel injector (6). (8) is provided.
As shown in FIGS. 2A and 2B, the fuel injection chamber (4) includes a compressed air guide plate (40) extending from the communication port (9) side to the inner side of the fuel injection chamber (4). ..
Therefore, as shown in FIG. 1A, the injection of the fuel (5) is electronically controlled, and the compressed air (10) and the fuel injector pushed into the fuel injection chamber (4) from the communication port (9) in the compression stroke. By adjusting the premix of the fuel (5) injected from (6), combustion in the combustion chamber (2) is optimized, and even if the bore diameter of the cylinder (1) is reduced, noise, fuel consumption, and smoke concentration Can be maintained well and the engine can be miniaturized.
Further, as shown in FIG. 1 (D), FIGS. 2 (A) and 2 (B) are oriented in a direction parallel to the cylinder center axis (1c) and orthogonal to the communication port center axis (1c). As shown in the above, the compressed air (10) that tends to diffuse from the central portion of the fuel injection chamber (4) to both sides in the lateral direction is guided by the compressed air guide plate (40) to the fuel injection chamber (4). Returned to the central portion, the speed of the compressed air (10) is maintained at a high speed, and the premixing of the compressed air (10) and the fuel (5) in the fuel injection chamber (4) is promoted.

As shown in FIGS. 2 (A) and 2 (B), the communication port (9) is configured to introduce compressed air that becomes a swirling flow swirling in the vortex chamber (4 at), and is configured in FIG. 2 (B). ), The fuel injector (6) is the central fuel on the lateral center side, with the direction perpendicular to the communication port center axis (1c) as the lateral direction when viewed in a direction parallel to the cylinder center axis (1c). The central fuel injection axis (6ac) of the central fuel injection hole (6a) and the central fuel (5a) injected from the central fuel injection hole (6a) are provided in the lateral direction of the vortex chamber (4at). It is oriented so as to pass through the central portion and the communication port (9) in order toward the main combustion chamber (2a).
As shown in FIG. 2B, a pair of compressed air guide plates (40) are provided on both lateral sides of the lateral central portion of the fuel injection chamber (4), and are substantially equal to the communication port central axis (9c). A compressed air guide gap (41) is formed between the pair of compressed air guide plates (40) and (40), and the gap inlet on the communication port (9) side of the compressed air guide gap (41) is formed. The width dimension of (41a) is set to be larger than the maximum width dimension of the communication port (2).

The engine ECU (26) is used in the electronic control device (8). ECU is an abbreviation for electronic control unit and is a microcomputer. As shown in FIG. 1A, an accelerator sensor (27), a crank shaft sensor (28), and a cylinder discrimination sensor (29) are electrically connected to the engine ECU (26). The accelerator sensor (27) transmits an accelerator position detection signal to the engine ECU (26) based on the detection of the operation position of the accelerator lever (not shown). The crank shaft sensor (28) detects the actual rotation speed and the crank angle of the crank shaft (15), and transmits the actual rotation speed detection signal and the crank angle detection signal to the engine ECU (26). The cylinder discrimination sensor (29) detects the phase of the valve drive camshaft (30) of FIG. 2 and transmits a camshaft phase detection signal to the engine ECU (26). This engine is a 4-cycle engine, and the valve drive camshaft (30) is a camshaft that opens and closes an intake valve (not shown) and an exhaust valve (25a).

The engine ECU (26) has an electronic governor function, and a deviation between the target rotation speed and the actual rotation speed of the engine is calculated based on the accelerator position detection signal and the actual rotation speed detection signal, and the engine load is calculated based on the calculation. Is calculated, and based on the target engine speed and engine load, the fuel control map stored in the memory sets the timing and amount of injection of the fuel (5) of the fuel injector (6), and the fuel injector ( An injector control signal is transmitted to the electromagnetic valve (6e) of 6). By this injector control signal, the solenoid valve (6e) of the fuel injector (6) is opened for a predetermined time at a predetermined timing, and a predetermined amount of fuel (5) is injected from the fuel injector (6) at a predetermined timing. The fuel (5) is light oil.

A potentiometer is used for the accelerator sensor (27) shown in FIG. 1 (A).
A pickup coil is used for the crank shaft sensor (28). The crank shaft sensor (28) is a proximity sensor that detects that a protrusion of a crank shaft detection disc (not shown) attached to the flywheel (22) passes in front of the sensor. The crank shaft detection disc has one starting point protrusion on the peripheral edge and a large number of phase protrusions provided at equal pitches.
A pickup coil is also used in the cylinder discrimination sensor (29). This cylinder discrimination sensor (29) is a proximity sensor that detects that a protrusion of a camshaft phase detection disk (not shown) attached to the valve drive camshaft (30) shown in FIG. 2 passes in front of the sensor. .. The camshaft phase detection disc has one protrusion on the periphery.
The crankshaft sensor (28) and the cylinder discrimination sensor (29) transmit an actual rotation speed detection signal, a crank angle detection signal, and a camshaft phase detection signal based on a protrusion pickup signal to the engine ECU (26), and the engine ECU (26). In), the actual rotation speed and crank angle of the engine are calculated from the actual rotation speed detection signal and the crank angle detection signal, and the stroke of each cylinder in the combustion cycle is determined from the camshaft phase detection signal.

The value of the surface roughness of the inner surface of the vortex chamber (4at) is 12.5a to 25a in arithmetic mean roughness (Ra).
Therefore, the compressed air (10) pushed into the vortex chamber (4 at) in the compression stroke comes into contact with the rough inner surface of the vortex chamber (4 at) , and the fuel (5) injected from the fuel injector (6) is generated by the generated minute vortex. It diffuses into the compressed air (10) without adhering to the inner surface of the vortex chamber (4 at), and the premixing of the compressed air (10) and the fuel (5) in the vortex chamber (4 at) is promoted.

When the value of the surface roughness of the inner surface of the vortex chamber (4at) is less than 12.5a in the arithmetic average roughness (Ra), a small vortex is not generated so much in the vortex chamber (4at) , and the fuel injector ( The fuel (5) injected from 6) adheres to the inner surface of the vortex chamber (4 at) , the fuel (5) does not diffuse into the compressed air (10), and the compressed air (10) and the fuel (5) are predicted. Mixing may be stagnant. On the other hand, when the value of the surface roughness of the inner surface of the vortex chamber (4at) exceeds 25a in the arithmetic mean roughness (Ra), the flow velocity of the compressed air (10) in contact with the inner surface of the vortex chamber (4at) decreases. The generation of minute vortices does not occur so much, and the premixing of the compressed air (10) and the fuel (5) may be stagnant for the same reason as described above.
On the other hand, when the value of the surface roughness of the inner surface of the vortex chamber (4at) is 12.5a to 25a in arithmetic average roughness (Ra), there is no problem as described above, and the compressed air (10). And fuel (5) premixing is promoted.

The value of the surface roughness of the inner peripheral surface of the communication port (9) is smaller than that of the inner surface of the vortex chamber (4 at) .
Therefore, the compressed air (10) in the combustion chamber is pushed into the vortex chamber (4at) at high speed by the guidance of the inner peripheral surface of the smooth communication port (9) without receiving a large resistance, and is pushed into the vortex chamber (4at). ) Is in contact with the rough inner surface, the generation of minute vortices is promoted, and the premixing of compressed air (10) and fuel (5) in the vortex chamber (4 at) is promoted.
The value of the surface roughness of the inner peripheral surface of the communication port (9) is 6.3a in arithmetic average roughness (Ra).

As shown in FIG. 1 (D), when viewed in a direction parallel to the cylinder center axis (1c), the direction orthogonal to the communication port center axis (9c) is the lateral direction, and the communication port (9) is the center in the lateral direction. It is provided with a central communication port (9a) on the side and side communication ports (9b) (9b) on both sides in the lateral direction.
Therefore, as shown in FIGS. 2B and 3, the central compressed air (10a) pushed into the vortex chamber (4at) from the central communication port (9a) and the side communication ports (9b) (9b) are pushed into the vortex chamber (4at). The fuel (5) is entrained in the compressed air (10b) (10b), and the fuel (5) is widely diffused in the compressed air (10), and the fuel (5) and the compressed air in the vortex chamber (4 at). Premixing of (10) is promoted.
Further, as shown in FIGS. 2B and 3, in the present invention, the side compressed air (10b) (10b) flows into the side space (4b) (4b) of the vortex chamber (4at) , and this side space. (4b) The flow of air in (4b) is promoted, and the air utilization rate in the vortex chamber (4at) is increased.

As shown in FIGS. 1 (B) and 1 (D), the distance between the side communication ports (9b) and (9b) center axes (9bc) and (9bc) increases as the vortex chamber (4at) approaches. It is configured to gradually narrow.
Therefore, as shown in FIGS. 2B and 3, the pair of side compressed air (10b) (10b) collides with the central compressed air (10a) in the vortex chamber (4at) from both sides, or mutually. It collides, is deflected to the side space (4b) (4b) side, flows into both side spaces (4b) (4b) in the lateral direction of the vortex chamber (4at) , and the air in this side space (4b) (4b). The flow of air is promoted, and the air utilization rate in the vortex chamber (4 at) is increased.

As shown in FIGS. 2B and 3, the fuel injector (6) has a central fuel injection hole (6a) on the lateral center side and side fuel injection holes (6b) (6b) on both sides in the lateral direction. Equipped with
The central fuel injection axis (6ac) of the central fuel injection hole (6a) is directed toward the communication port (9) (central communication port (9a) side, and the side fuel injection axis (6b) (6b) of the side fuel injection hole (6b). 6bc) (6bc) are directed to both lateral sides of the central fuel injection axis (6ac).
Therefore, as shown in FIGS. 2B and 3, the central fuel (5a) injected from the central fuel injection hole (6a) is diffused in the central compressed air (10a), and the side compressed air (10b). The side fuels (5b) and (5b) are diffused in (10b), and the premixing of the fuel (5) and the compressed air (10) in the vortex chamber (4at) is promoted.

As shown in FIG. 2A, the central fuel injection axis (6ac) of the central fuel injection hole (6a) is the center where the central compressed air (10a), which is a swirling flow swirling in the vortex chamber (4at), is introduced. It is directed to the central communication port (9a) via the corner (4c) side of the boundary between the communication port (9a) and the vortex chamber (4at) .
Therefore, the central fuel (5a) is caught in the wake of the corner portion (4c) generated in the central compressed air (10a), and the central fuel (5a) and the central compressed air (10a) are predicted in the vortex chamber (4at) . Mixing is promoted.

In this embodiment, the central fuel injection axis (6ac) is directed toward the central communication port (9a) via a position in contact with the corner portion (4c). The central fuel injection axis (6ac) passes through one of a position along the corner (4c), a position with the corner (4c), and a position near the corner (4c) away from the corner (4c). It suffices if it is directed to the central communication port (9a).

As shown in FIGS. 2B and 3, the side fuel injection axes (6bc) (6bc) of the side fuel injection holes (6b) (6b) are directed to the inner peripheral surface of the vortex chamber (4at) . ..
Therefore, as shown in FIGS. 2B and 3, the side fuels (5b) and (5b) are involved in the side compressed air (10b) (10b) flowing along the inner peripheral surface of the vortex chamber (4at) . , The armpit fuels (5b) (5b) are diffused in the armpit compressed air (10b) (10b), and the premixing of the fuel (5) and the compressed air (10) in the vortex chamber (4 at) is promoted.

As shown in FIG. 1 (B), at the position where the side fuel injection axis (6bc) (6bc) abuts on the inner peripheral surface of the vortex chamber (4at) , the central fuel injection axis (6ac) is the central communication port (9a). It is the position on both sides in the lateral direction just beside the position in contact with the corner portion (4c) of.
When the central fuel injection axis (6ac) is directed toward the central communication port (9a) via a position closer to the corner (4c), the side fuel injection axis (6bc) (6bc) is the vortex chamber ( 6bc). The position of the inner peripheral surface of 4at) is directly beside the position near the corner (4c) of the central communication port (9a) through which the central fuel injection axis (6ac) directed to the central communication port (9a) passes . It is positioned on both sides in the lateral direction.

As shown in FIG. 1 (A), the combustion chamber (2) in the cylinder (1) is the main combustion chamber (2a), and the vortex chamber (4 at) is the sub-combustion chamber (4a).
Therefore, a part of the fuel (5) injected from the fuel injector (6) is premixed and burned with the compressed air (10) in the sub-combustion chamber (4a), and the remaining unburned fuel is premixed and burned. The combustion gas is ejected from the communication port (9) to the main combustion chamber (2a), the fuel (5) is widely diffused in the main combustion chamber (2a), and combustion in the main combustion chamber (2a) is promoted.

As shown in FIGS. 2A and 2B, the auxiliary combustion chamber (4a) is a vortex chamber (4at).
Therefore, as shown in FIGS. 2B and 3, the fuel (5) injected from the fuel injector (6) is the compressed air (4at) pushed from the main combustion chamber (2a) into the vortex chamber (4at). It is caught in the vortex flow of 10), and the premixing of the fuel (5) and the compressed air (10) in the vortex chamber (4 at) is promoted.

As shown in FIGS. 2B and 3, the side fuel injection axis (6bc) of the side fuel injection hole (6b) is directed in the turning direction of the side compressed air (10b) swirling in the vortex chamber (4at). ing.
Therefore, as shown in FIGS. 2B and 3, the side fuel (5b) rides on the side compressed air (10b) and swirls in the sub-combustion chamber (4a), and in the sub-combustion chamber (4a). Premixing of fuel (5) and compressed air (10) is promoted.

As shown in FIG. 4B, the main combustion chamber (2a) is formed between the piston (1a) and the cylinder head (3) in the cylinder (1).
As shown in FIG. 4A, the piston (1a) includes a combustion gas guide groove (37) provided on the top surface and three valve recesses (38) (38) (39), and the combustion gas guide is provided. The start end of the groove (37) faces the communication port (9) near the peripheral wall of the cylinder (1), and the end of the combustion gas guide groove (37) crosses the cylinder center axis (1c) and faces the communication port (9). It extends to the opposite side of 9) and communicates with the three valve recesses (38) (38) (39).
As shown in FIG. 4 (A), the combustion gas guide groove (37) is formed in a fan shape when viewed in a direction parallel to the cylinder center axis (1c), and as shown in FIG. 4 (B), the starting end portion. Is the deepest and gradually becomes shallower as it approaches the end. Of the three valve recesses shown in FIG. 4A, the pair of small-diameter valve recesses (38) and (38) are intake valve recesses, and the large-diameter valve recesses (39) are exhaust valve recesses.

As shown in FIG. 4B, the auxiliary combustion chamber (4a) is formed between the recess (3a) on the bottom surface of the cylinder head (3) and the mouthpiece (3b) fitted in the recess (3a). , The communication port (9) is formed in the base (3b).
As shown in FIG. 4B, the auxiliary combustion chamber (4a) is a spherical vortex chamber (4at), and the communication port central axis (9c) of the communication port (9) is the bottom surface (3c) of the mouthpiece (3b). ) With an elevation angle of 45 °, the main combustion chamber (2a) is directed toward the tangential direction of the inner peripheral surface of the sub-combustion chamber (4a).
Therefore, the compressed air (10) pushed into the vortex chamber (4 at) from the communication port (9) in the compression stroke swirls as a standing vortex in the vortex chamber (4 at). The reference numeral (4t) in FIG. 4 {B} is the center of the vortex of the compressed air (10).
A glow plug (4e) is inserted in the vortex chamber (4at).

As shown in FIGS. 1 (B) to 1 (E), the central communication port center axis (9ac) substantially coincides with the communication port center axis (9c), and as shown in FIG. 1 (C), the side communication port center axis line. (9bc) is smaller than the central communication port central axis (9ac) and has an elevation angle.
As shown in FIGS. 1B to 1E, the passage cross-sectional area of the pair of side communication ports (9b) (9b) gradually narrows as it approaches the auxiliary combustion chamber (4a), and the side compressed air (10b). (10b) is gradually accelerated as it approaches the auxiliary combustion chamber (4a).

The injection pressure of the liquid fuel (5) from the fuel injector (6) shown in FIG. 1 (A) is set to 5 to 50 MPa (megapascal).
The injection pressure of the liquid fuel (5) from the fuel injector (6) is generally set to 120 to 160 MPa of that of the existing common rail diesel engine that injects fuel directly into the combustion chamber in the cylinder. On the other hand, it is set quite low.
If the injection pressure of the fuel (5) from the fuel injector (6) is less than 5 MPa, the penetration force of the fuel (5) in the vortex chamber (4 at) is insufficient, and if it exceeds 50 MPa, the fuel in the vortex chamber (4 at) is insufficient. The flight time of (5) is insufficient, and in any case, the premixing of the fuel (5) and the compressed air (10) in the injector chamber (4 at) may be stagnant. On the other hand, at 5 to 50 MPa, the above problem does not occur, and the premixing of the fuel (5) and the compressed air (10) in the vortex chamber (4 at) is promoted.
Further, the injection pressure of the fuel (5) from the fuel injector (6) is only 5 to 50 MPa, and although it is a diesel engine, the fuel injector (6) such as a gasoline injection system for low-pressure fuel injection and the fuel accumulator (7) ) Parts can be diverted, and parts can be shared with other low-pressure fuel injection systems.

As shown in FIG. 1 (A), this engine includes a fuel accumulator (7) for accumulating fuel (5) injected from a fuel injector (6), and the fuel accumulator (7) is an accumulator (11). And a fuel feed pump (12) that supplies fuel (5) to the accumulator (11).
Therefore, the injection pressure of the fuel (5) from the fuel injector (6) is only 5 to 50 MPa, and the accumulator (11) and the fuel feed pump (12) such as a gasoline injection system for low-pressure fuel injection are used even though the engine is a diesel engine. Can be diverted as it is, and the parts of the fuel accumulator (7) can be shared with other low-pressure fuel injection systems.

As shown in FIG. 1A, the accumulator (11) is a delivery pipe (11a) that distributes the fuel (5) to a plurality of fuel injectors (6).
Therefore, the fuel pressure in the delivery pipe (11a) becomes about 5 to 50 MPa, and the delivery pipe (11a) such as a gasoline injection system for low-pressure fuel injection can be diverted as it is even though it is a diesel engine. The parts of the multi-cylinder low-pressure fuel injection system and the fuel accumulator (7) can be shared.

As shown in FIG. 1A, the delivery pipe (11a) includes a fuel pressure sensor (11b), and the fuel pressure in the delivery pipe (11a) detected by the fuel pressure sensor (11b) is a fuel pressure detection signal. Is sent to the engine ECU (26), and a pump control signal is sent from the engine ECU (26) to the electric actuator (not shown) of the fuel feed pump (12). The supply amount of the fuel (5) to the delivery pipe (11a) is controlled, and the fuel pressure in the delivery pipe (11a) is adjusted. As shown in FIG. 5, the fuel feed pump (12) is pumped by a pump drive cam driven by an electric actuator.
Reference numeral (13) in FIG. 1A is a safety valve, and when the fuel pressure in the delivery pipe (11a) exceeds a predetermined upper limit, the valve is opened and the fuel pressure in the delivery pipe (11a) is released. Decrease.

As a method for adjusting the fuel pressure in the delivery pipe (11a), an electric spill valve (not shown) for leaking the fuel in the delivery pipe (11a) to the fuel tank (35) side is provided, and the fuel pressure sensor (11b) is used. The detected fuel pressure in the delivery pipe (11a) is sent to the engine ECU (26) as a fuel pressure detection signal, and a valve control signal is sent from the engine ECU (26) to the actuator of the electric spill valve to send the electric spill valve. The amount of leakage of the fuel (5) from the delivery pipe (11a) may be controlled by the opening degree control.

As shown in FIG. 5, in this embodiment, the fuel feed pump (12), the delivery pipe (11a), and the fuel injector (6) of the existing gasoline injection system are diverted as they are, even though the engine is a diesel engine.

As shown in FIG. 1 (A), fuel is supplied to the fuel feed pump (12) from the fuel tank (35), and a part of the fuel (5) of the fuel feed pump (12) and the fuel injector (6) is used. , Overflows and returns to the fuel tank (35) via the fuel return passage (36), and the air pool of the fuel feed pump (12) and the fuel injector (6) is eliminated.

In the above embodiment, the injection pressure of the fuel (5) from the fuel injector (6) is 5 to 50 MPa from the viewpoint of promoting the premixing of the fuel (5) and the compressed air (10) in the vortex chamber (4 at). However, it is more desirable to set this injection pressure to 10 to 40 MPa. This is because the function of promoting premixing can be obtained more reliably.

The injection of the fuel (5) of the fuel injector (6) includes a main injection and a pre-injection prior to the main injection.
Therefore, the pre-injection fuel (5) is mixed with the compressed air (10) in the vortex chamber (4 at) and burned, and the main injection fuel (5) is ignited by the pre-injection combustion gas and burned in the combustion chamber. Combustion in (2) is promoted.

As shown in FIG. 6, the engine water cooling device includes a radiator (21) that dissipates heat from the engine cooling water and a water pump (18) that sucks the engine cooling water radiated by the radiator (21) and pumps it to the cylinder jacket. And the cylinder jacket (31), the cylinder head jacket (32) of FIG. 2 communicating with the cylinder jacket (31), and the return of the engine cooling water from the cylinder head jacket (32) to the radiator (21) and its stop. A water flange (34) having a built-in thermostat valve (33) to control and a return pipe (not shown) for returning the engine cooling water of the cylinder head jacket (32) from the water flange (34) to the water pump (18). I have.

In the engine water cooling device, while the temperature of the engine cooling water is relatively low, the entire amount of the engine cooling water is sucked into the water pump (18) from the return pipe by closing the thermostat valve (33), and the radiator (21) is used. ) Is circulated between the cylinder jacket (31) and the cylinder head jacket (32) to warm up the engine.
When the temperature of the engine cooling water rises, the opening of the thermostat valve (33) causes the engine cooling water to flow between the radiator (21), the water pump (18), the cylinder jacket (31), and the cylinder head jacket (32). Is circulated in that order to cool the engine. A part of the engine cooling water is sucked into the water pump (18) from the return pipe and bypasses the radiator (21).

Although the description of the embodiment of the present invention is as described above, the present invention is not limited to the above embodiment.
Although the two-cylinder engine has been described in the above embodiment, the present invention can also be applied to a single-cylinder engine or a multi-cylinder engine having three or more cylinders.
Further, the vortex chamber (4 at) does not necessarily have to be a sub chamber type, and may be a chamber having no communication port (9), that is, a chamber in which the bottom surface of the cylinder head (3) is simply recessed.
Further, the fuel injection holes of the fuel injector (6) do not necessarily have to be plural, and may be single. In this case, the injection of the fuel (5) injected from the fuel injection hole does not necessarily have to be directed to the inner surface of the vortex chamber (4 at) , but is directed to the main combustion chamber (2a) through the communication port (9). It may be the one that was given. Further, when there is no communication port (9), it may be directed to the main combustion chamber (2a) through the opening of the vortex chamber (4 at) .

In the above embodiment, two sensors including a crank shaft sensor (28) and a cylinder discrimination sensor (29) are used to calculate the actual rotation speed and crank angle of the engine and to determine which stroke of the combustion cycle each cylinder is in. It is based on the detection of, but instead of these two sensors, based on the detection of one phase sensor (not shown), the calculation of the actual rotation speed and crank angle of the engine and the combustion cycle of each cylinder It is also possible to determine which process it is in. A pickup coil is used for this phase sensor. This phase sensor is a proximity sensor that detects that a protrusion of a phase detection disk (not shown) attached to the valve camshaft (30) passes in front of the sensor. The phase detection sensor includes one starting point protrusion on the peripheral edge and a large number of phase protrusions provided at equal pitches. This phase sensor transmits the pickup signal of the protrusion to the engine ECU (26), and the engine ECU (26) is based on the period of the pulse wave of the pickup signal and the order of the pulse wave of the protrusion passing in front of the sensor. The actual rotation speed of the engine and the crank angle are calculated, and the phase of the pulse wave of the protrusion passing in front of the sensor is used to determine the stroke of the combustion cycle of each cylinder.

In this embodiment, the injection pressure of the fuel (5) from the fuel injector (6) is only 5 to 50 MPa, so that the fuel injection type diesel engine is an electronic fuel injection type diesel engine, but the auxiliary chamber type combustion chamber of the mechanical cam fuel injection type diesel engine. The low-pressure fuel injection pump for fuel injection can be diverted as the fuel feed pump (12), and in this case, the parts can be shared with the mechanical cam fuel injection type diesel engine. The fuel feed pump (12) is driven by the existing fuel injection camshaft (14).

(1) ... Cylinder, (1c) ... Cylinder center axis, (2) ... Combustion chamber, (2a) ... Main combustion chamber, (3) ... Cylinder head, (4) ... Fuel injection chamber, (4a) ... Secondary combustion Chamber, (4at) ... vortex chamber, (4c) ... corner, (5) ... fuel, (6) ... fuel injector, (6a) ... central fuel injection hole, (6ac) ... central fuel injection axis, (6b) ... side fuel injection hole, (6bc) ... side fuel injection axis, (6c) ... fuel injection axis, (7) ... fuel accumulator, (8) ... electronic control device, (9) ... communication port, (9a) ... Central communication port, (9ac) ... Central communication port central axis, (9b) ... Side communication port, (9bc) ... Side communication port central axis, (9c) ... Communication port center axis, (10b) ... Side compressed air, ( 11) ... Accumulator, (11a) ... Delivery pipe, (12) ... Fuel feed pump, (40) ... Compressed air guide plate.

Claims (11)

A combustion chamber (2) in the cylinder (1), a fuel injection chamber (4) in the cylinder head (3), and a communication port (9) for communicating the combustion chamber (2) and the fuel injection chamber (4). It is equipped with a fuel injector (6) facing the fuel injection chamber (4) and an electronic control device (8) that controls the injection timing and injection amount of the fuel (5) injected from the fuel injector (6).
The fuel injection chamber (4) is provided with a compressed air guide plate (40) extending from the communication port (9) side to the back side of the fuel injection chamber (4).
The combustion chamber (2) in the cylinder (1) is the main combustion chamber (2a), and the fuel injection chamber (4) is the vortex chamber (4at).
The communication port (9) is configured to introduce compressed air that becomes a swirling flow in the vortex chamber (4at), and is viewed in a direction parallel to the cylinder center axis (1c), and the communication port center axis (1c). ), The fuel injector (6) has a central fuel injection hole (6a) on the lateral center side, and the central fuel injection axis (6ac) and the central fuel of the central fuel injection hole (6a). The central fuel (5a) injected from the injection hole (6a) passes through the lateral central portion of the vortex chamber (4at) and the communication port (9) in order, and is directed toward the main combustion chamber (2a). Attached,
A pair of compressed air guide plates (40) are provided on both lateral sides of the lateral central portion of the fuel injection chamber (4), and are oriented substantially parallel to the communication port center axis (9c), and a pair of compressed air guide plates (40) are provided. A compressed air guide gap (41) is formed between the air guide plates (40) and (40), and the width dimension of the gap inlet (41a) on the communication port (9) side of the compressed air guide gap (41) is the communication port. A diesel engine characterized in that it is set larger than the maximum width dimension of (2). In the diesel engine according to claim 1 ,
The communication port (9) includes a central communication port (9a) on the lateral center side and side communication ports (9b) (9b) on both sides in the lateral direction .
The fuel injector (6) is provided with a central fuel injection hole (6a) on the lateral center side and side fuel injection holes (6b) (6b) on both sides in the lateral direction.
The central fuel injection axis (6ac) of the central fuel injection hole (6a) is directed toward the central communication port (9a) , and the side fuel injection axes (6bc) (6bc) of the side fuel injection holes (6b) (6b) Directed to both sides of the central fuel injection axis (6ac) in the lateral direction ,
The central fuel injection axis (6ac) of the central fuel injection hole (6a) is a central communication port (9a) and a vortex chamber (4at ) for introducing central compressed air (10a) which is a swirling flow in the vortex chamber (4at). ) Is directed toward the central communication port (9a) via the position on the corner (4c) side of the boundary.
The side fuel injection axes (6bc) (6bc) of the side fuel injection holes (6b) (6b) are directed toward the inner peripheral surface of the vortex chamber (4at) .
The position where the side fuel injection axis (6bc) (6bc) abuts on the inner peripheral surface of the vortex chamber (4at) is the position where the central fuel injection axis (6ac) contacts the corner (4c) of the central communication port (9a). A diesel engine characterized by being positioned on both sides in the lateral direction. In the diesel engine according to claim 2,
The position where the side fuel injection axis (6bc) (6bc) abuts on the inner peripheral surface of the vortex chamber (4at) is the position where the central fuel injection axis (6ac) contacts the corner (4c) of the central communication port (9a). Instead of being positioned on both sides in the lateral direction
The position where the side fuel injection axis (6bc) (6bc) abuts on the inner peripheral surface of the vortex chamber (4at) is the central communication port (6ac) through the central communication port (9a) facing the central communication port (9a). A diesel engine characterized in that it is located on both sides in the lateral direction at a position closer to the corner (4c) of 9a). In the diesel engine according to claim 2 or claim 3 .
It is understood that the distance between the central axes (9bc) and (9bc) of the side communication ports (9b) (9b) is gradually narrowed as the fuel injection chamber (4) is approached. Characterized diesel engine. In the diesel engine according to any one of claims 2 to 4.
A diesel engine characterized in that the side fuel injection axis (6bc) of the side fuel injection hole (6b) is directed in the turning direction of the side compressed air (10b) that turns in the vortex chamber (4at). In the diesel engine according to any one of claims 1 to 5 .
A diesel engine characterized in that the value of the surface roughness of the inner surface of the vortex chamber (4at) is 12.5a to 25a in arithmetic average roughness (Ra). In the diesel engine according to any one of claims 1 to 6 .
A diesel engine characterized in that the value of the surface roughness of the inner peripheral surface of the communication port (9) is smaller than that of the inner surface of the vortex chamber (4 at) . In the diesel engine according to any one of claims 1 to 7 .
A diesel engine characterized in that the injection pressure of the fuel (5) from the fuel injector (6) is set to 5 to 50 MPa. In the diesel engine according to claim 8 ,
A fuel accumulator (7) for accumulating the fuel (5) injected from the fuel injector (6) is provided, and the fuel accumulator (7) supplies the fuel (5) to the accumulator (11) and the accumulator (11). A diesel engine characterized by having a fuel feed pump (12). In the diesel engine according to claim 9 ,
The accumulator (11) is a diesel engine characterized by being a delivery pipe (11a) that distributes the fuel (5) to a plurality of fuel injectors (6). In the diesel engine according to any one of claims 1 to 10 .
A diesel engine characterized in that the injection of the fuel (5) of the fuel injector (6) includes a main injection and a pre-injection prior to the main injection.

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