JP6505563B2 - diesel engine - Google Patents

Description

  The present invention relates to a diesel engine, and more particularly to a diesel engine capable of improving the fuel supply accuracy of a gas generation fuel supply pump.

  Conventionally, as a diesel engine, liquid fuel is supplied to a flammable gas generator through a gas generating fuel supply passage by a gas generating fuel supply pump, and flammable gas is generated from the liquid fuel by the flammable gas generator. There is an exhaust gas treatment apparatus in which combustible gas is mixed into engine exhaust, engine exhaust temperature is raised by combustion heat of combustible gas, and PM deposited on DPF is incinerated and removed by heat of engine exhaust For example, refer to Patent Document 1).

JP, 2007-51580, A (refer to Drawing 1 and Drawing 2)

<< Problem >> The fuel supply accuracy of the gas generation fuel supply pump may be low.
In the case of Patent Document 1, low temperature liquid fuel is supplied to the fuel supply pump for gas generation in cold weather, and gas generation is performed by increasing the viscosity and waxing (solidification of paraffin component) of the liquid fuel by the fuel supply pump for gas generation. The amount of fuel supplied from the fuel supply pump to the combustible gas generator may fluctuate, and the fuel supply accuracy of the gas generation fuel supply pump may be lowered.

  An object of the present invention is to provide a diesel engine capable of improving the fuel supply accuracy of a gas generation fuel supply pump.

(Specific items of the invention common to the invention according to claim 1 and the invention according to claim 3)
As illustrated in FIGS. 1 and 2, the liquid fuel (5) is supplied to the combustible gas generator (3) through the gas generation fuel supply passage (12) by the gas generation fuel supply pump (2). The combustible gas (6) is generated from the liquid fuel (5) by the combustible gas generator (3), and the combustible gas (6) is mixed into the engine exhaust (7) to burn the combustible gas (6) In a diesel engine comprising an exhaust treatment device in which engine exhaust (7) is heated by heat and PM accumulated in DPF (4) is incinerated and removed by heat of engine exhaust (7),
As illustrated in FIGS. 1 and 2, the liquid fuel (5) of the fuel tank (1) is supplied by the fuel supply pump (8) to the fuel injection pump (9), and the liquid injection pump (9) 5) is injected from the fuel injection valve (10) through the fuel injection pipe (9a), and the liquid fuel (5) overflowed from the fuel injection pump (9) and the fuel injection valve (10) is the fuel return passage (11) A fuel injection device which is returned to the fuel tank (1) by
As illustrated in FIGS. 1 and 2, the gas generation fuel supply passage (12) is downstream of the fuel injection pump (9) and the fuel injection valve (10) in the fuel return direction from the fuel return passage (11). It has been derived.
(Invention specific matters specific to the invention according to claim 1)
As illustrated in FIG. 1, the gas generation fuel supply passage (12) has a lower projecting portion (12a), and the lower projecting portion (12a) is drawn downward from the fuel return passage (11). A diesel engine characterized in that it has an upwardly inverted lower projecting shape, and a gas supply fuel supply pump (2) is disposed downstream of the lower projecting portion (12a) in the fuel supply direction.
(Invention specific matters specific to the invention according to claim 3)
As illustrated in FIG. 2, a gas-liquid separation chamber (14) is provided, and the gas-liquid separation chamber (14) is in the fuel return direction downstream of the fuel injection pump (9) and the fuel injection valve (10). A diesel engine characterized in that it is provided in the passage (11), and the gas supply fuel supply passage (12) is derived from the liquid fuel reservoir (14a) of the gas-liquid separation chamber (14).

(Invention of claim 1)
The invention according to claim 1 has the following effects.
<< Effect 1-1 >> The fuel supply accuracy of the gas generation fuel supply pump can be enhanced.
As illustrated in FIGS. 1 and 2, the gas generation fuel supply passage (12) is downstream of the fuel injection pump (9) and the fuel injection valve (10) in the fuel return direction from the fuel return passage (11). Since it is derived, the liquid fuel (5) supplied to the gas generation fuel supply pump (2) is supplied to the cylinder block (18) via the fuel injection pump (9) and the fuel injection valve (10) even when it is cold. ) and is heat warming the cylinder head (19), is prevented high viscosity and waxing of the liquid fuel (5) in the gas generating fuel supply pump (2) is, from the gas generator fuel supply pump (2) The problem that the amount of fuel supplied to the flammable gas generator (3) fluctuates is prevented.
Further, the pulsation pressure of the liquid fuel (5) by the fuel supply pump (8) and the fuel injection pump (9) is attenuated by the fuel return passage (11), the fuel injection valve (10) and the fuel supply passage (12) for gas generation. Therefore, the gas generation fuel supply pump (2) is unlikely to be affected by the pulsating pressure of the liquid fuel (5) by the fuel supply pump (8) or the fuel injection pump (9). ) Is prevented from fluctuating the amount of fuel supplied to the flammable gas generator (3).
For these reasons, the fuel supply accuracy of the gas generation fuel supply pump (2) can be enhanced.

<< Effect 1-2 >> The fuel supply accuracy of the gas generation fuel supply pump can be improved.
As illustrated in FIG. 1, the gas generation fuel supply passage (12) has a lower projecting portion (12a), and the lower projecting portion (12a) is drawn downward from the fuel return passage (11). And the fuel supply pump (2) for gas generation is disposed downstream of the lower projection (12a) in the fuel supply direction, so that the fuel supply passage (12 for gas generation) is formed. ), The damping efficiency of the pulsating pressure of the gas generation fuel supply passage (12) is high, and the amount of fuel supplied from the gas generation fuel supply pump (2) to the flammable gas generator (3) fluctuates. Is prevented.
In addition, the lower projecting portion (12a) prevents the entry of air from the fuel return passage (11), and the entry of air causes the fuel supply pump for gas generation (2) to the combustible gas generator (3) It is possible to prevent the problem that the amount of fuel supply fluctuates.
For these reasons, the fuel supply accuracy of the gas generation fuel supply pump (2) can be enhanced.

(Invention of claim 2 )
The invention according to claim 2 has the following effect in addition to the effect of the invention according to claim 1 .
<< Effect >> It is possible to prevent a problem that the fuel supply passage for gas generation is clogged by waxing or freezing of liquid fuel in a cold region.
As illustrated in FIG. 1, since the lower projecting portion (12a) is provided with the fuel drain device (13), the liquid fuel (5) accumulated in the fuel supply passage (12) for gas generation is a fuel drain device (13). ), And when shipping the engine as a cold region specification, there is a defect that the liquid fuel of normal temperature specification used in the pre-shipment test of the exhaust treatment device is left in the gas generation fuel supply passage (12) It is possible to prevent the problem that the gas generating fuel supply passage (12) is clogged by waxing or freezing of the liquid fuel (5) in a cold region.

(Invention of claim 3 )
The invention according to claim 3 exerts the following effect in addition to the effect 1-1 of the invention according to claim 1.
<< Effect >> The fuel supply accuracy of the gas generation fuel supply pump can be improved.
As illustrated in FIG. 2, the pulsation pressure of the liquid fuel (5) by the fuel supply pump (8) and the fuel injection pump (9) is also attenuated in the gas-liquid separation chamber (14), and the fuel supply pump for gas generation (2 Is unlikely to be affected by the pulsating pressure of the liquid fuel (5) by the fuel supply pump (8) or the fuel injection pump (9), and from the fuel supply pump for gas generation (2) to the combustible gas generator (3) It is possible to prevent the problem that the fuel supply amount fluctuates.
Further, the air contained in the liquid fuel (5) is separated in the gas-liquid separation chamber (14), and the liquid fuel (5) from which the air is separated is supplied from the liquid fuel reservoir (14a) to the fuel supply passage (12) for gas generation. Since the air flows into the gas generation fuel supply passage (12), the problem that the fuel supply amount from the gas generation fuel supply pump (2) to the combustible gas generator (3) fluctuates is prevented.
For these reasons, the fuel supply accuracy of the gas generation fuel supply pump (2) can be enhanced.

(Invention of claim 4 )
The invention according to claim 4 has the following effect in addition to the effect of the invention according to claim 3 .
<< Effect >> It is possible to prevent the problem that the liquid fuel reservoir is blocked by waxing or freezing of the liquid fuel in a cold region.
As illustrated in FIG. 2, since the liquid fuel reservoir (14a) includes the fuel drain device (13), the liquid drain (5) accumulated in the liquid fuel reservoir (14a) is drained by the fuel drain device (13). When the engine is shipped as a cold region specification, the defect that the liquid fuel of the normal temperature specification used in the pre-shipment test of the exhaust treatment device remains in the liquid fuel reservoir (14a) is prevented, It is possible to prevent the liquid fuel reservoir (14a) from being blocked due to waxing or freezing of the liquid fuel (5).

(Invention of claim 5 )
The invention according to claim 5 exerts the following effects in addition to the effects of the invention according to claim 3 or claim 4 .
<< Effect >> The fuel supply accuracy of the gas generation fuel supply pump can be improved.
As illustrated in FIG. 3, the passage inlet (16a) inclines upward from the liquid fuel reservoir (14a) to the passage central (16b) along the central axis extension line (15a) of the fuel introduction passage (15). And the passage outlet (16c) is inclined downward from the passage center (16b) to the liquid fuel reservoir (14a), and the gas generating fuel supply passage (12) is directed upward from the passage center (16b). Therefore, even if waxing of the liquid fuel (5) occurs in the fuel guide passage (16) when it is cold, the paraffin component inclines from the passage center (16b) to the passage inlet (16a) and the passage outlet (16c) Easily flow to the liquid fuel reservoir (14a) by its own weight, and the passage central part (16b) is not easily clogged, and the amount of fuel supplied from the gas generation fuel supply pump (2) to the combustible gas generator (3) Fluctuating faults are prevented.
Also, even if the central part (16b) of the passage is stuffed with paraffin components, when the liquid fuel (5) is introduced from the fuel introduction passage (15) to the liquid fuel reservoir (14a), the liquid fuel (5) is introduced into the passage inlet. It is pushed into the passage central part (16b) from the part (16a) and collides with the paraffin component to disperse the paraffin component, the clogging of the passage central part (16b) is eliminated, and the fuel supply pump for gas generation (2) burns It is possible to prevent the problem that the amount of fuel supplied to the hydrogen gas generator (3) fluctuates.
For these reasons, the fuel supply accuracy of the gas generation fuel supply pump (2) can be enhanced.

(Invention according to claim 6 )
The invention according to claim 6 exerts the following effects in addition to the effects of the invention according to any of claims 1 to 5 .
<< Effect >> The fuel supply accuracy of the gas generation fuel supply pump can be improved.
As illustrated in FIGS. 1 and 2, the gas generation fuel supply passage (12) is provided with an air vent (17) connected to the fuel inlet (2a) of the gas generation fuel supply pump (2). Therefore, filling the liquid fuel (5) into the fuel supply passage (12) for gas generation up to the fuel inlet (2a) of the fuel supply pump (2) for gas generation while performing air removal with the air removal device (17) Can prevent the fluctuation of the amount of fuel supplied from the gas generating fuel supply pump (2) to the flammable gas generator (3) by the air reservoir of the gas generating fuel supply pump (2), and the gas generating fuel can be prevented. The fuel supply accuracy of the supply pump (2) can be enhanced.

It is a figure explaining the diesel engine concerning a 1st embodiment of the present invention. It is a figure explaining the diesel engine concerning a 2nd embodiment of the present invention. It is explanatory drawing of the modification of the gas-liquid separation chamber used with the engine of FIG.

  FIG. 1 is a view for explaining a diesel engine according to a first embodiment of the present invention, and FIGS. 2 and 3 are views for explaining a diesel engine according to a second embodiment of the present invention. The in-line four-cylinder diesel engine will be described.

First, the first embodiment will be described.
This engine is equipped with an exhaust treatment device.
As shown in FIG. 1, in the exhaust treatment device, the liquid fuel (5) is supplied to the combustible gas generator (3) through the gas generation fuel supply passage (12) by the gas generation fuel supply pump (2). The flammable gas (6) is generated from the liquid fuel (5) by the flammable gas generator (3), and the flammable gas (6) is mixed into the engine exhaust (7), and the flammable gas (6) The heat of combustion raises the temperature of the engine exhaust (7), and the heat of the engine exhaust (7) incinerates and removes the PM deposited on the DPF (4).

  The gas generation fuel supply pump (2) is an electric pump. The flammable gas generator (3) comprises a flammable gas generating catalyst (3a). The flammable gas generation catalyst (3a) is an oxidation catalyst. The exhaust treatment device includes a blower (20), an exhaust treatment case (21), a DOC (22), a control device (23), a DOC inlet temperature sensor (24), a DPF inlet temperature sensor (25), and a differential pressure sensor (26). , The ignition device (30). The blower (20) is an electric blower and uses an intake passage (27) of the engine as an air supply source. The exhaust treatment case (21) is disposed in the middle of the exhaust path (28) of the engine, and the DOC (22) is accommodated on the upstream side in the exhaust direction in the exhaust treatment case (21) Is housed. DOC is a diesel oxidation catalyst, and DPF is an abbreviation of diesel particulate filter. The control device (23) is an engine ECU. The ECU is an abbreviation of an electronic control unit and is a microcomputer. The ignition device (30) is a glow plug.

The sensors (24), (25), (26), the fuel supply pump for gas generation (2), the blower (20), and the ignition device (30) are electrically connected to the control unit (23). Detection signals from the sensors (24), (25) and (26) are received by the control device (23), and based on the detection signals, the fuel supply pump for gas generation (2), the blower (20) and the ignition device (30) Is controlled by the controller (23).
Specifically, the control device (23) estimates the amount of PM deposited on the DPF (4) based on the detection of the pressure difference between the inlet and the outlet of the DPF (4) by the differential pressure sensor (26). When the PM deposition value reaches a predetermined value, the fuel supply pump for gas generation (2), the blower (20), and the igniter (30) are controlled based on the command signal of the control device (23) to generate combustible gas The liquid fuel (5) and the air (29) are supplied to the vessel (3), and the liquid fuel (5) is oxidized by the flammable gas generation catalyst (3a) to form a flammable gas (6), and the exhaust path (28) Mixed with the engine exhaust (7) , the combustible gas (6) is catalytically burned by the DOC (22), the engine heat (7) is heated by this combustion heat, and the PM accumulated in the DPF (4) is incinerated It is removed and the DPF (4) is regenerated.

If the DOC inlet temperature is less than the activation temperature of DOC (22), the flammable gas (6) is ignited by the igniter (30), and the engine exhaust (7 ) occurs by flame combustion of the flammable gas (6). ) , And the DOC inlet temperature becomes the activation temperature of DOC (22). In addition, the controller (23) controls the fuel supply pump for gas generation (2) and the blower (20) so that the DPF inlet temperature becomes a predetermined PM burning temperature, and the combustible gas generator (3) The supply of liquid fuel (5) and air (29) is adjusted. Further, the combustible gas (6) is burned by the oxygen in the engine exhaust (7) , but the secondary air is supplied to the combustible gas (6) from the blower (20) to promote the combustion.

The engine includes a fuel injection device.
As shown in FIG. 1, in the fuel injection device, the liquid fuel (5) of the fuel tank (1) is supplied to the fuel injection pump (9) by the fuel supply pump (8), and the liquid fuel is pumped by the fuel injection pump (9). (5) is injected from the fuel injection valve (10) through the fuel injection pipe (9a), and the liquid fuel (5) overflowed from the fuel injection pump (9) and the fuel injection valve (10) ) To the fuel tank (1).

  The fuel supply pump (8) is a mechanical pump, attached to the cylinder block (18), and driven by a pump cam of a fuel injection camshaft (not shown). The fuel injection pump (9) is a cam driven plunger type row pump, is attached to the cylinder block (18), and is driven by a fuel injection cam of a fuel injection camshaft. The fuel injection camshaft is driven by a crankshaft (not shown). The fuel injection valve (10) is attached to the cylinder head (19).

  As shown in FIG. 1, the gas generation fuel supply passage (12) is derived from the fuel return passage (11) downstream of the fuel injection pump (9) and the fuel injection valve (10) in the fuel return direction. .

As shown in FIG. 1, the gas generation fuel supply passage (12) is provided with a lower projecting portion (12a), and after the lower projecting portion (12a) is drawn downward from the fuel return passage (11), The lower projecting shape is turned upside down, and the gas generating fuel supply pump (2) is disposed downstream of the lower projecting portion (12a) in the fuel supply direction.
The lower projecting portion (12a) is provided with a fuel drain device (13).
The gas generation fuel supply passage (12) is provided with an air vent (17) connected to the fuel inlet (2a) of the gas generation fuel supply pump (2).
The lower projecting portion (12a) has a U-shaped lower projecting shape.
The fuel drain device (13) and the air vent device (17) are both manual on-off type cocks.

Next, a second embodiment shown in FIG. 2 will be described.
As shown in FIG. 2, the fuel injection device has a gas-liquid separation chamber (14), and the gas-liquid separation chamber (14) is downstream of the fuel injection pump (9) and the fuel injection valve (10) in the fuel return direction. The fuel supply passage (12) for gas generation is provided in the fuel return passage (11) and is led out from the liquid fuel reservoir (14a) of the gas-liquid separation chamber (14).

As shown in FIG. 2, the liquid fuel reservoir (14a) is provided with a fuel drain device (13).
The other structure is the same as that of the first embodiment, and in FIG. 2, the same elements as those of the first embodiment are given the same reference numerals as those of FIG.

The modification of the gas-liquid separation chamber of the second embodiment is as follows.
As shown in FIG. 3, the gas-liquid separation chamber (14) comprises a fuel introduction passage (15), a fuel guide passage (16) and a fuel lead passage (31) , and the fuel introduction passage (15) is a liquid fuel reservoir (14a). The fuel delivery passage (31) is downwardly inclined outward from the liquid fuel reservoir (14a). The fuel guide passage (16) comprises a passage inlet (16a), a passage center (16b) and a passage outlet (16c).
As shown in FIG. 3, the passage inlet (16a) inclines from the liquid fuel reservoir (14a) to the passage central (16b) along the central axis extension line (15a) of the fuel introduction passage (15). The passage outlet (16c) is inclined downward from the passage center (16b) to the liquid fuel reservoir (14a), and the gas generating fuel supply passage (12) is directed upward from the passage center (16b) There is.

  As shown in FIG. 3, the gas-liquid separation chamber (14) is connected to the middle of the fuel return passage (11) via the fuel introduction passage (15) and the fuel discharge passage (31). The fuel introduction passage (15) is formed in a block (32) accommodated in the gas-liquid separation chamber (14). When it is cold, the wax component (5a) of the liquid fuel (5) which slips down the inclination of the passage inlet portion (16a) and the passage outlet portion (16c) of the fuel guide passage (16) accumulates in the liquid fuel reservoir (14a).

(1) Fuel tank
(2) Fuel supply pump for gas generation
(2a) Fuel inlet
(3) Combustible gas generator
(4) DPF
(5) Liquid fuel
(6) Flammable gas
(7) Engine exhaust
(8) Fuel supply pump
(9) Fuel injection pump
(9a) Fuel injection pipe
(10) Fuel injection valve
(11) Fuel return passage
(12) Fuel supply passage for gas generation
(12a) Lower projecting part
(13) Fuel drain device
(14) Gas-liquid separation chamber
(14a) Liquid fuel reservoir
(15) Fuel introduction passage
(15a) Central axis extension line
(16) Fuel guide passage
(16a) Passage entrance
(16b) Central area of passage
(16c) passage exit
(17) Air bleeding device

Claims (6)

The liquid fuel (5) is supplied to the flammable gas generator (3) through the gas generation fuel supply passage (12) by the gas generation fuel supply pump (2), and the liquid is discharged by the flammable gas generator (3) The combustible gas (6) is generated from the fuel (5), the combustible gas (6) is mixed into the engine exhaust (7), and the engine exhaust (7) is heated by the combustion heat of the combustible gas (6) In a diesel engine equipped with an exhaust treatment device in which PM accumulated in the DPF (4) is incinerated and removed by the heat of the engine exhaust (7)
The liquid fuel (5) of the fuel tank (1) is supplied to the fuel injection pump (9) by the fuel supply pump (8), and the liquid fuel (5) by the fuel injection pump (9) via the fuel injection pipe (9a) Fuel injected from the fuel injection valve (10) and the liquid fuel (5) overflowed from the fuel injection pump (9) and the fuel injection valve (10) is returned to the fuel tank (1) by the fuel return passage (11) Equipped with an injector
The gas generation fuel supply passage (12) is derived from the fuel return passage (11) downstream of the fuel injection pump (9) and the fuel injection valve (10) in the fuel return direction ,
The gas generation fuel supply passage (12) has a lower projecting portion (12a), and the lower projecting portion (12a) is directed downward from the fuel return passage (11) and then inverted upward. A diesel engine characterized in that it has a shape and a fuel supply pump (2) for gas generation is disposed downstream of the lower projecting portion (12a) in the fuel supply direction. In the diesel engine according to claim 1 ,
A diesel engine characterized in that the lower projecting portion (12a) comprises a fuel drain device (13). The liquid fuel (5) is supplied to the flammable gas generator (3) through the gas generation fuel supply passage (12) by the gas generation fuel supply pump (2), and the liquid is discharged by the flammable gas generator (3) The combustible gas (6) is generated from the fuel (5), the combustible gas (6) is mixed into the engine exhaust (7), and the engine exhaust (7) is heated by the combustion heat of the combustible gas (6) In a diesel engine equipped with an exhaust treatment device in which PM accumulated in the DPF (4) is incinerated and removed by the heat of the engine exhaust (7)
The liquid fuel (5) of the fuel tank (1) is supplied to the fuel injection pump (9) by the fuel supply pump (8), and the liquid fuel (5) by the fuel injection pump (9) via the fuel injection pipe (9a) Fuel injected from the fuel injection valve (10) and the liquid fuel (5) overflowed from the fuel injection pump (9) and the fuel injection valve (10) is returned to the fuel tank (1) by the fuel return passage (11) Equipped with an injector
The gas generation fuel supply passage (12) is derived from the fuel return passage (11) downstream of the fuel injection pump (9) and the fuel injection valve (10) in the fuel return direction ,
A gas-liquid separation chamber (14) is provided, and the gas-liquid separation chamber (14) is provided in the fuel return passage (11) downstream of the fuel injection pump (9) and the fuel injection valve (10) in the fuel return direction. A diesel engine characterized in that a gas generation fuel supply passage (12) is led out from a liquid fuel reservoir (14a) of a gas-liquid separation chamber (14). In the diesel engine according to claim 3 ,
A diesel engine, characterized in that the liquid fuel reservoir (14a) comprises a fuel drain device (13). The diesel engine according to claim 3 or 4
The gas-liquid separation chamber (14) is provided with a fuel introduction passage (15) and a fuel guide passage (16), and the fuel introduction passage (15) is inclined upward to the liquid fuel reservoir (14a), and the fuel guide passage (16) Has a passage inlet (16a), a passage central portion (16b) and a passage outlet (16c),
The passage inlet (16a) inclines from the liquid fuel reservoir (14a) to the passage central portion (16b) along the central axis extension line (15a) of the fuel introduction passage (15), and the passage outlet (16c) Is inclined downward from the passage central portion (16b) to the liquid fuel reservoir (14a), and the gas generating fuel supply passage (12) is directed upward from the passage central portion (16b) diesel engine. The diesel engine according to any one of claims 1 to 5 ,
A diesel engine characterized in that a gas generating fuel supply passage (12) is provided with an air vent (17) connected to a fuel inlet (2a) of the gas generating fuel supply pump (2).

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