JP2020106019A - diesel engine - Google Patents

Abstract

To provide a diesel engine capable of downsizing an engine.SOLUTION: A diesel engine includes: a combustion chamber 2 in a cylinder 1, a fuel injection chamber 4 in a cylinder head 3, a communication port 9 that communicates the combustion chamber 2 and the fuel injection chamber 4, a fuel injector 6 facing the fuel injection chamber 4, and an electronic control device 8 that controls an injection timing and an injection amount of a fuel 5 injected from the fuel injector 6. Assuming a direction orthogonal to a communication port center axis 9x when viewed from a direction parallel to a cylinder center axis 1c, as a lateral direction, the communication port 9 is equipped with a center communication port 9a on a lateral direction center side and side communication ports 9b and 9b on lateral direction both sides.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a diesel engine, and more particularly to a diesel engine that can be downsized.

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

JP, 2014-20278, A (refer to Drawing 1)

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

An object of the present invention is to provide a diesel engine that can be downsized.

The main constitution of the present invention is as follows.
As illustrated in FIG. 1A, 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) ), a fuel injector (6) facing the fuel injection chamber (4), and an electronic control for controlling the injection timing and injection amount of the fuel (5) injected from the fuel injector (6). Equipped with a device (8),
As illustrated in FIG. 1D, when viewed in a direction parallel to the cylinder center axis line (1c), the direction orthogonal to the communication port center axis line (9c) is the lateral direction, and the communication port (9) is the lateral direction. A diesel engine having a central communication port (9a) on the center side and side communication ports (9b) (9b) on both sides in the lateral direction.

<<Effect 1>> The engine can be downsized.
As illustrated in FIG. 1(A), in the present invention, the injection of fuel (5) is electronically controlled, and compressed air (10) is pushed into the fuel injection chamber (4) from the communication port (9) in the compression stroke. By adjusting the premixing of the fuel (5) injected from the fuel 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, The smoke concentration can be maintained well, and the engine can be downsized.

<<Effect 2>> Premixing of the fuel (5) and the compressed air (10) in the fuel injection chamber (4) is promoted.
As illustrated in FIGS. 2B and 3, in the present invention, the central compressed air (10a) pushed into the fuel injection chamber (4) from the central communication port (9a) and the side communication ports (9b) (9b). ), the fuel (5) is entrained in the side compressed air (10b) (10b), the fuel (5) is widely diffused in the compressed air (10), and the fuel (5) in the fuel injection chamber (4) is discharged. ) And compressed air (10) is promoted.

<<Effect 3>> The air utilization rate in the fuel injection chamber (4) is increased.
As illustrated in FIGS. 2B and 3, in the present invention, the side compressed air (10b) (10b) flows into the side spaces (4b) (4b) of the fuel injection chamber (4), and the side spaces (4b) The flow of air in (4b) is promoted, and the air utilization rate in the fuel injection chamber (4) is increased.

FIG. 1 is a diagram illustrating a diesel engine according to an embodiment of the present invention, FIG. 1(A) is a block diagram illustrating the signal and fuel flow of this engine, and FIG. 1(B) is used in the engine of FIG. 1(A). 1C is a side view of the communication port, FIG. 1D is a plan view of the communication port, and FIG. 1E is a view in the direction E of FIG. 1B. It is a figure explaining the subcombustion chamber of the diesel engine which concerns on embodiment of this invention, FIG.2(A) is an elevation sectional side view, FIG.2(B) is a BB sectional drawing of FIG.2(A). .. It is the III-III sectional view taken on the line of FIG. 2(A). BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a plan view of a main combustion chamber, and FIG. 1B is a vertical cross-sectional side view of a main combustion chamber and a sub combustion chamber, illustrating a combustion chamber of a diesel engine according to an embodiment of the present invention. is there. 1 is a front elevational sectional view of a diesel engine according to an embodiment of the present invention. FIG. 6 is a side view in vertical section of the engine of FIG. 5. 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. In this embodiment, a water-cooled in-line two-cylinder electronic fuel injection type diesel engine will be described.

In this engine, the installation direction of the crankshaft (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, the engine is mounted on a cylinder block (16), a cylinder head (3) mounted on the cylinder block (16), and a cylinder head (3). Cylinder head cover (17), water pump (18) and oil pump (19) assembled on the front part of the cylinder block (16) shown in FIG. 6, and engine cooling assembled on the front part of the water pump (18) A fan (20), a radiator (21) arranged in front of the engine cooling fan (20), a flywheel (22) arranged at the rear of the cylinder block (16), and a lower part 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 an exhaust downstream side of the exhaust manifold (25).
The intake manifold (24) is arranged on one side of the cylinder head (3), and the exhaust manifold (25) is arranged on the other side 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) (9) for communicating with each other, a fuel injector (6) facing the fuel injection chamber (4), and an electronic control device for controlling the injection timing and injection amount of the fuel (5) injected from the fuel injector (6). (8) is provided.
Therefore, as shown in FIG. 1(A), the injection of the fuel (5) is electronically controlled, and the compressed air (10) and the fuel injector which are pushed into the fuel injection chamber (4) from the communication port (9) in the compression stroke. By adjusting the premixing 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, smoke concentration Can be maintained well, and the engine can be downsized.

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

The engine ECU (26) has an electronic governor function, calculates the deviation between the target rotation speed and the actual rotation speed of the engine based on the accelerator position detection signal and the actual rotation speed detection signal, and based on the calculation, the engine load. Is calculated, and the fuel injection map of the fuel injector (6) sets the timing and amount of injection of the fuel (5) by the fuel control map stored in the memory based on the target engine speed and engine load. An injector control signal is transmitted to the solenoid valve (6e) of 6). By this injector control signal, the electromagnetic valve (6e) of the fuel injector (6) is opened at a predetermined timing for a predetermined time, 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.
A pickup coil is used for the crankshaft sensor (28). The crankshaft sensor (28) is a proximity sensor that detects when a protrusion of a crankshaft detection disk (not shown) attached to the flywheel (22) passes in front of the sensor. The crankshaft detection disk is provided with one starting point projection on the periphery and a large number of phase projections provided at equal pitches.
A pickup coil is also used for the cylinder discrimination sensor (29). The cylinder discrimination sensor (29) is a proximity sensor that detects when a projection of a camshaft phase detection disk (not shown) attached to the valve operating camshaft (30) shown in FIG. 2 passes in front of the sensor. .. The camshaft phase detection disk has one protrusion on the peripheral edge.
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 the pick-up signal of the protrusion to the engine ECU (26). ), the actual engine speed and crank angle are calculated from the actual engine speed detection signal and the crank angle detection signal, and the stroke of the combustion cycle of each cylinder is determined from the camshaft phase detection signal.

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 centered in the lateral direction. The central communication port (9a) on one side and the side communication ports (9b) (9b) on both lateral sides in the lateral direction are provided.
Therefore, as shown in FIGS. 2(B) and 3, from the central compressed air (10a) pushed into the fuel injection chamber (4) from the central communication port (9a) and from the side communication ports (9b) (9b). The fuel (5) is entangled in the side air (10b) (10b) that is pushed in, the fuel (5) is widely diffused in the compressed air (10), and the fuel (5) in the fuel injection chamber (4) becomes Premixing of compressed air (10) is facilitated.
Further, as shown in FIGS. 2(B) and 3, in the present invention, the side compressed air (10b) (10b) flows into the side spaces (4b) (4b) of the fuel injection chamber (4), The flow of air in the spaces (4b) (4b) is promoted and the air utilization rate in the fuel injection chamber (4) is increased.

As shown in FIGS. 1(B) and 1(D), the distances between the side communication port central axes (9bc) and (9bc) of the side communication ports (9b) and (9b) are closer to the fuel injection chamber (4). , Is gradually narrowed.
Therefore, as shown in FIG. 2B and FIG. 3, the pair of side compressed air (10b) (10b) collides with the central compressed air (10a) in the fuel injection chamber (4) from both sides or the mutual side compressed air (10b) (10b) collides with each other. And is deflected to the side space (4b) (4b) side, flows into both side spaces (4b) (4b) in the lateral direction of the fuel injection chamber (4), and inside the side space (4b) (4b) Of the air is promoted, and the air utilization rate in the fuel injection chamber (4) is increased.

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

As shown in FIG. 2(A), the central fuel injection axis (6ac) of the central fuel injection hole (6a) is located on the corner (4c) side of the boundary between the central communication port (9a) and the fuel injection chamber (4). After that, it is directed to the central communication port (9a).
Therefore, the central fuel (5a) is caught in the wake of the corner (4c) generated in the central compressed air (10a), and the central fuel (5a) and the central compressed air (10a) in the fuel injection chamber (4) are separated. Premixing is facilitated.

In this embodiment, the central fuel injection axis (6ac) is directed to the central communication port (9a) through a position in contact with the corner portion (4c). The central fuel injection axis (6ac) passes through any 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 may be directed to the central communication port (9a).

As shown in FIG. 2(B) and FIG. 3, the side fuel injection axes (6bc) (6bc) of the side fuel injection holes (6b) (6b) are directed toward the inner peripheral surface of the fuel injection chamber (4). There is.
Therefore, as shown in FIGS. 2B and 3, the side fuel (5b) (5b) is entrained in the side compressed air (10b) (10b) flowing along the inner peripheral surface of the fuel injection chamber (4). As a result, the side fuel (5b) (5b) is diffused in the side compressed air (10b) (10b) to promote premixing of the fuel (5) and the compressed air (10) in the fuel injection chamber (4). ..

As shown in FIG. 1(B), at the position where the side fuel injection axis (6bc) (6bc) abuts the inner peripheral surface of the fuel injection chamber (4), the central fuel injection axis (6ac) is a corner (4c). It is a position on both sides in the lateral direction, right next to the position where it touches.
When the central fuel injection axis (6ac) is directed to the central communication port (9a) through a position near the corner (4c), the side fuel injection axis (6bc) (6bc) is The positions where the inner peripheral surface of (4) abuts are positions on both sides in the lateral direction, which are right next to the positions near the corners (4c).

As shown in FIG. 1(A), the combustion chamber (2) in the cylinder (1) is the main combustion chamber (2a), and the fuel injection chamber (4) is the auxiliary 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 auxiliary combustion chamber (4a), and the remaining unburned fuel is premixed and burned. The combustion gas is ejected from the communication port (9) into 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 and FIG. 3, the auxiliary combustion chamber (4a) is a vortex chamber (4at).
Therefore, as shown in FIGS. 2(B) and 3, the fuel (5) injected from the fuel injector (6) is compressed air (5) pushed from the main combustion chamber (2a) into the vortex chamber (4at). Entrained in the vortex flow of (10), premixing of the fuel (5) and the compressed air (10) in the vortex chamber (4at) is promoted.

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

As shown in FIG. 4(B), the main combustion chamber (2a) is formed in the cylinder (1) between the piston (1a) and the cylinder head (3).
As shown in FIG. 4(A), the piston (1a) is provided with a combustion gas guide groove (37) provided on the top surface and three valve recesses (38) (38) (39). 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 communicates with the communication port (9). It extends to the side opposite to 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 has a starting end portion as shown in FIG. 4(B). Is the deepest, and becomes gradually shallower as it approaches the end.
Of the three valve recesses shown in FIG. 4(A), the pair of small-diameter valve recesses (38, 38) are intake valve recesses, and the large-diameter valve recess (39) is an exhaust valve recess.

As shown in FIGS. 2(A) and 4(B), the sub-combustion chamber (4a) has a recess (3a) on the bottom surface of the cylinder head (3) and a mouthpiece (3b) fitted in the recess (3a). And the communication port (9) is formed in the base (3b).
As shown in FIGS. 2(A) and 4(B), the auxiliary combustion chamber (4a) is a spherical vortex chamber (4at), and the central axis (9c) of the communication port of the communication port (9) is The elevation angle (α) with respect to the bottom surface (3c) of 3b) is 45° and is oriented from the main combustion chamber (2a) side to the tangential direction of the inner peripheral surface of the auxiliary combustion chamber (4a).
Therefore, the compressed air (10) pushed into the vortex chamber (4at) from the communication port (9) in the compression stroke swirls as a standing vortex flow in the vortex chamber (4at). Reference numeral (4t) in FIGS. 2A and 4B is the eddy center of the standing vortex of the compressed air (10).
A glow plug (4 g) is inserted in the vortex chamber (4 at).

As shown in FIGS. 1(B) to 1(E) and FIG. 2(A), the central communication port central axis (9ac) substantially coincides with the communication port central axis (9c) and is shown in FIG. 1(C). Thus, the elevation angle (β) of the side communication port central axis (9bc) with respect to the bottom surface (3c) of the base (3b) is smaller than the elevation angle (α) of the central communication port central axis (9ac).
As shown in FIGS. 1(B) to 1(E), the passage cross-sectional areas of the pair of side communication ports (9b), (9b) become gradually narrower as they approach the auxiliary combustion chamber (4a), and the side compressed air (10b) is obtained. (10b) is gradually accelerated as it approaches the auxiliary combustion chamber (4a).
As shown in FIGS. 2(A) and 2(B), the vortex chamber (4at) has auxiliary communication ports (9d) (9d) separated from the central communication port (9a) on both sides of the central communication port (9a). 2A, the auxiliary compressed air (10d) flows into the vortex chamber (4at) from the auxiliary communication ports (9d) (9d) in the compression stroke, and the side spaces (4b) (4b) ), the flow of air is promoted, and the air utilization rate in the vortex chamber (4 at) is increased.
The auxiliary communication ports (9d) (9d) are oriented substantially at right angles to the bottom surface (3c) of the base (3b).

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 type diesel engine that directly injects the fuel into the combustion chamber in the cylinder. However, it is set quite low.
When the injection pressure of the fuel (5) from the fuel injector (6) is less than 5 MPa, the penetrating force of the fuel (5) in the fuel injection chamber (4) is insufficient, and when it exceeds 50 MPa, the fuel injection chamber (4) is in the fuel injection chamber (4). The flight time of the fuel (5) is insufficient, and in any case, premixing of the fuel (5) and the compressed air (10) in the fuel injection chamber (4) 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 fuel injection chamber (4) is promoted.
Further, the injection pressure of the fuel (5) from the fuel injector (6) is 5 to 50 MPa, and even though it is a diesel engine, the fuel injector (6) and the fuel pressure accumulator (7) such as a gasoline injection system of low pressure fuel injection are used. ) 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 pressure accumulator (7) for accumulating fuel (5) injected from a fuel injector (6), and the fuel pressure accumulator (7) includes an accumulator (11). And a fuel feed pump (12) for supplying fuel (5) to the accumulator (11).
Therefore, the injection pressure of the fuel (5) from the fuel injector (6) is 5 to 50 MPa, and the accumulator (11) and the fuel feed pump (12) such as a low pressure fuel injection gasoline injection system are used even though the diesel engine is used. Can be diverted as it is, and the parts of the fuel pressure accumulator (7) can be shared with other low pressure fuel injection systems.

As shown in FIG. 1(A), the accumulator (11) is a delivery pipe (11a) that distributes the fuel (5) to the 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 pressure accumulator (7) can be shared.

As shown in FIG. 1(A), 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) as a control signal, and a pump control signal is sent from the engine ECU (26) to an electric actuator (not shown) of the fuel feed pump (12). The amount of fuel (5) supplied 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. 1(A) is a safety valve, which is opened when the fuel pressure in the delivery pipe (11a) exceeds a predetermined upper limit value, and the fuel pressure in the delivery pipe (11a) is released. Lower.

As a method of 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 a 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 the engine ECU (26) sends a valve control signal to the actuator of the electric spill valve, thereby The amount of leakage of the fuel (5) from the delivery pipe (11a) may be controlled by controlling the opening degree.

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 they are diesel engines.

As shown in FIG. 1(A), fuel is supplied from the fuel tank (35) to the fuel feed pump (12), and a part of the fuel (5) of the fuel feed pump (12) and the fuel injector (6) is Then, it overflows and returns to the fuel tank (35) through the fuel return passage (36), and the air accumulation in 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 5 from the viewpoint of promoting premixing of the fuel (5) and the compressed air (10) in the fuel injection chamber (4). Although it is set to 50 MPa, it is more preferable 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 fuel (5) from the fuel injector (6) comprises a main injection and a pre-injection prior to the main injection.
Therefore, the pre-injected fuel (5) is mixed with the compressed air (10) in the fuel injection chamber (4) and burned, and the main-injected fuel (5) is ignited by the pre-injected combustion gas and burned. Combustion in the chamber (2) is promoted.

As shown in FIG. 6, the engine water cooling device includes a radiator (21) for radiating heat of the engine cooling water, and a water pump (18) for sucking the engine cooling water radiated by the radiator (21) and pumping it to the cylinder jacket. 2, the cylinder jacket (31), the cylinder head jacket (32) of FIG. 2 communicating with the cylinder jacket (31), the circulation of engine cooling water from the cylinder head jacket (32) to the radiator (21), and its stopping. A water flange (34) with a built-in thermostat valve (33) for controlling and a return pipe (not shown) for circulating engine cooling water of the cylinder head jacket (32) from the water flange (34) to the water pump (18). I have it.

In the engine water cooling system, while the temperature of the engine cooling water is relatively low, the thermostat valve (33) is closed, and the entire amount of the engine cooling water is sucked into the water pump (18) from the return pipe and the radiator (21 ) Is bypassed to circulate 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 engine cooling water is opened between the radiator (21), the water pump (18), the cylinder jacket (31) and the cylinder head jacket (32) by opening the thermostat valve (33). Are circulated in that order to cool the engine. A part of the engine cooling water is sucked into the water pump (18) through the return pipe and bypasses the radiator (21).

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments.
Although the two-cylinder engine is described in the above embodiment, the present invention can be applied to a single-cylinder engine or a multi-cylinder engine having three or more cylinders.
Further, the fuel injection chamber (4) 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.
Moreover, the fuel injection hole of the fuel injector (6) does 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 fuel injection chamber (4), but to the main combustion chamber (2a) via the communication port (9). It may be directed. When the communication port (9) is not provided, it may be directed to the main combustion chamber (2a) through the opening of the fuel injection chamber (4).

In the above-described embodiment, the calculation of the actual engine speed and crank angle and the determination of the stroke of each combustion cycle of each cylinder are performed by two sensors including a crankshaft sensor (28) and a cylinder determination sensor (29). However, instead of these two sensors, one phase sensor (not shown) is used to detect the actual engine speed and crank angle, It is also possible to discriminate which process it is. A pickup coil is used for this phase sensor. This phase sensor is a proximity sensor that detects when a projection of a phase detection disk (not shown) attached to the valve operating cam shaft (30) passes in front of the sensor. The phase detection sensor includes one starting point projection on the periphery and a large number of phase projections provided at equal pitches. This phase sensor transmits the pick-up signal of the protrusion to the engine ECU (26), and the engine ECU (26) determines the period of the pulse wave of the pick-up signal or the ordinal number of the pulse wave of the protrusion passing in front of the sensor. The actual engine speed and crank angle are calculated, and the stroke of the combustion cycle of each cylinder is determined based on the phase of the pulse wave of the protrusion that has passed in front of the sensor.

In this embodiment, since the injection pressure of the fuel (5) from the fuel injector (6) is 5 to 50 MPa, the auxiliary chamber combustion chamber of the mechanical cam fuel injection diesel engine is an electronic fuel injection diesel engine. A low-pressure fuel injection pump for a vehicle can be used as the fuel feed pump 12, and in this case, the parts can be shared with the mechanical cam fuel injection diesel engine. The fuel feed pump (12) is driven by the existing fuel injection cam shaft (14).

(1)... Cylinder, (1c)... Cylinder center axis, (2)... Combustion chamber, (2a)... Main combustion chamber, (3)... Cylinder head, (4)... Fuel injection chamber, (4a)... Sub 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 pressure accumulator, (8) ... Electronic control unit, (9) ... Communication port, (9a) ... Central communication port, (9ac)... Central communication port central axis line, (9b)... Side communication port, (9bc)... Side communication port center axis line, (9c)... Communication port center axis line, (10b)... Side compressed air, ( 11)... Accumulator, (11a)... Delivery pipe, (12)... Fuel feed pump.

Claims (12)

A combustion chamber (2) in the cylinder (1), a fuel injection chamber (4) in the cylinder head (3), a communication port (9) for communicating the combustion chamber (2) and the fuel injection chamber (4), A fuel injector (6) facing the fuel injection chamber (4); and an electronic control unit (8) for controlling the injection timing and injection amount of the fuel (5) injected from the fuel injector (6),
When viewed in a direction parallel to the cylinder center axis (1c), the direction orthogonal to the communication port center axis (9c) is defined as the lateral direction, and the communication port (9) has a central communication port (9a) on the lateral center side. A diesel engine characterized by having side communication openings (9b) (9b) on both sides in the lateral direction. In the diesel engine according to claim 1,
The distance between the side communication port central axes (9bc) (9bc) of the side communication ports (9b) (9b) is configured to be gradually narrowed toward the fuel injection chamber (4). A characteristic diesel engine. In the diesel engine according to claim 1 or 2,
The fuel injector (6) includes a central fuel injection hole (6a) on the lateral center side and side fuel injection holes (6b) (6b) on both lateral sides,
The central fuel injection axis (6ac) of the central fuel injection hole (6a) is directed toward the communication port (9) side, and the side fuel injection axis (6bc) (6bc) of the side fuel injection holes (6b) (6b) is in the center. A diesel engine characterized by being directed to both sides of the fuel injection axis (6ac) in the lateral direction. In the diesel engine according to claim 3,
The central fuel injection axis (6ac) of the central fuel injection hole (6a) passes through the position on the corner (4c) side of the boundary between the central communication port (9a) and the fuel injection chamber (4) to reach the central communication port (9a). A diesel engine characterized by being aimed at. In the diesel engine according to claim 3 or 4,
The diesel engine characterized in that the side fuel injection axes (6bc) (6bc) of the side fuel injection holes (6b) (6b) are directed to the inner peripheral surface of the fuel injection chamber (4). In the diesel engine according to any one of claims 1 to 5,
A diesel engine, wherein a combustion chamber (2) in a cylinder (1) is a main combustion chamber (2a) and a fuel injection chamber (4) is a sub combustion chamber (4a). The diesel engine according to claim 6,
A diesel engine characterized in that the auxiliary combustion chamber (4a) is a vortex chamber (4at). The diesel engine according to claim 7,
The side fuel injection axis (6bc) of the side fuel injection hole (6b) is oriented in the swirling direction of the side compressed air (10b) swirling in the vortex chamber (4at). In the diesel engine according to any one of claims 1 to 8,
The diesel engine characterized in that the injection pressure of the fuel (5) from the fuel injector (6) is set to 5 to 50 MPa. The diesel engine according to claim 9,
A fuel pressure accumulator (7) for accumulating the fuel (5) injected from the fuel injector (6) is provided, and the fuel pressure accumulator (7) supplies the fuel (5) to the accumulator (11) and the accumulator (11). A diesel engine, characterized in that it is equipped with a fuel feed pump (12). The diesel engine according to claim 10,
The diesel engine, wherein the accumulator (11) is a delivery pipe (11a) that distributes the fuel (5) to the plurality of fuel injectors (6). In the diesel engine according to any one of claims 1 to 11,
The diesel engine, characterized in that the injection of fuel (5) from the fuel injector (6) comprises a main injection and a pre-injection prior to the main injection.

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