JP6430353B2 - diesel engine - Google Patents

Description

  The present invention relates to a diesel engine, and more particularly to a diesel engine that can improve the fuel supply accuracy of a gas supply fuel supply pump.

  Conventionally, as a diesel engine, liquid fuel is supplied to a combustible gas generator through a gas generating fuel supply passage by a gas generating fuel supply pump, and combustible gas is generated from the liquid fuel by the combustible gas generator. Provided with an exhaust treatment device configured such that combustible gas is mixed into the engine exhaust, the temperature of the engine exhaust is raised by the combustion heat of the combustible gas, and the PM deposited on the DPF is incinerated and removed by the heat of the engine exhaust (See, for example, Patent Document 1).

Japanese Patent Laying-Open No. 2007-51580 (see FIGS. 1 and 2)

<< Problem >> The fuel supply accuracy of the gas generation fuel supply pump may be lowered.
In Patent Document 1, a low-temperature liquid fuel is supplied to a gas generation fuel supply pump at the time of cold, and gas generation is performed by increasing the viscosity or waxing (solidification of paraffin components) of the liquid fuel with the gas generation fuel supply pump. The fuel supply amount 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.

  The subject of this invention is providing the diesel engine which can improve the fuel supply precision of the fuel supply pump for gas generation.

Invention specific matters of the invention according to claim 1 are as follows.
The liquid fuel (5) is supplied to the combustible gas generator (3) by the gas generating fuel supply pump (2) through the gas generating fuel supply passage (12), and the liquid fuel (5) is liquidated by the combustible gas generator (3). Combustible gas (6) is generated from fuel (5), combustible gas (6) is mixed into engine exhaust (7), and engine exhaust (7) is heated by the combustion heat of combustible gas (6). In a diesel engine comprising an exhaust treatment device configured to incinerate and remove PM deposited on the DPF (4) by the heat of the engine exhaust (7),
The fuel supply pump (8) supplies the liquid fuel (5) in the fuel tank (1) to the fuel injection pump (9). The fuel injection pump (9) supplies the liquid fuel (5) through the fuel injection pipe (9a). The liquid fuel (5) injected from the fuel injection valve (10) and overflowed from the fuel injection pump (9) and the fuel injection valve (10) is returned to the fuel tank (1) through the fuel return passage (11). Comprising a fuel injection device configured in
A gas-liquid separation tank (14), a fuel bypass passage (15), and a temperature-sensitive fuel valve (16) are provided. The gas-liquid separation tank (14) is more than the fuel injection pump (9) and the fuel injection valve (10). The fuel return passage (11) is provided downstream of the fuel return direction, and the fuel bypass passage (15) is led out from the liquid fuel reservoir (14a) of the gas-liquid separation tank (14) and bypasses the fuel tank (1). The lead-out end of the fuel bypass passage (15) is connected to the fuel passage (8a) between the fuel tank (1) and the fuel supply pump (8), and the gas generation fuel supply passage (12) is connected to the fuel bypass passage (15). The temperature-sensitive fuel valve (16) is provided in the fuel bypass passage (15) downstream of the outlet position of the gas generation fuel supply passage (12) in the fuel passage direction, and the temperature-sensitive fuel valve (16 ), The temperature-sensitive fuel valve (16) is closed and the predetermined temperature is exceeded. Less than in the case of the temperature sensitive fuel valve (16) is configured to be opened, diesel engine, characterized in that.

(Invention of Claim 1)
The invention according to claim 1 has the following effects.
<Effect> The fuel supply accuracy of the gas generation fuel supply pump can be increased.
As illustrated in FIG. 1, the gas-liquid separation tank (14) is provided in the fuel recirculation passage (11) downstream of the fuel injection pump (9) and the fuel injection valve (10) in the fuel recirculation direction. The passage (15) is led out from the liquid fuel reservoir (14a) of the gas-liquid separation tank (14), and the gas generation fuel supply passage (12) is led out from the fuel bypass passage (15). The liquid fuel (5) supplied to the gas generation fuel supply pump (2) is heated by the cylinder block (18) and the cylinder head (19) via the fuel injection pump (9) and the fuel injection valve (10). To prevent the liquid fuel (5) from being increased in viscosity and waxing in the gas generation fuel supply pump (2), and from the gas generation fuel supply pump (2) to the combustible gas generator (3). The problem that the fuel supply amount fluctuates is prevented.
The pulsation pressure of the liquid fuel (5) by the fuel supply pump (8) and the fuel injection pump (9) is the fuel recirculation passage (11), the fuel injection valve (10), the gas-liquid separation tank (14), and the fuel bypass passage. (15) and the gas generation fuel supply passage (12), the gas generation fuel supply pump (2) pulsates the liquid fuel (5) by the fuel supply pump (8) and the fuel injection pump (9). The problem that the fuel supply amount from the gas generation fuel supply pump (2) to the combustible gas generator (3) fluctuates is prevented.
Further, the air contained in the liquid fuel (5) is separated in the gas-liquid separation tank (14), and the liquid fuel (5) from which the air has been separated passes from the liquid fuel reservoir (14a) through the fuel bypass passage (15). Since it flows into the gas generation fuel supply passage (12), the amount of fuel supplied from the gas generation fuel supply pump (2) to the combustible gas generator (3) in the air reservoir in the gas generation fuel supply passage (12) The problem of fluctuation is prevented.
Further, when the temperature is cold, the temperature-sensitive fuel valve (16) is opened, and the liquid fuel (15) passing through the fuel bypass passage (15) bypasses the liquid fuel tank (1). The temperature of the liquid fuel (5) supplied to (2) is likely to rise, preventing the liquid fuel (5) from being increased in viscosity and waxing by the gas generating fuel supply pump (9), and supplying the gas generating fuel. The problem that the fuel supply amount from the 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 increased.

(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> The fuel supply accuracy of the gas generation fuel supply pump can be increased.
As illustrated in FIG. 1, the gas generating fuel supply passage (12) includes a lower protruding portion (12a), and the lower protruding portion (12a) is led out downward from the fuel bypass passage (15). The gas generating fuel supply pump (2) is disposed downstream of the lower protruding portion (12a) in the fuel supply direction, so that the gas generating fuel supply passage (12 ) Becomes longer, the pulsation pressure damping efficiency of the gas generating fuel supply passage (12) is high, and the fuel supply amount from the gas generating fuel supply pump (2) to the combustible gas generator (3) varies. Is prevented.
Further, the air in the fuel bypass passage (15) is unlikely to flow into the gas generation fuel supply passage (12) at the lower protruding portion (12a), and the air is stored in the gas generation fuel supply passage (12). The problem that the fuel supply amount from the 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 increased.

(Invention of Claim 3)
The invention according to claim 3 has the following effect in addition to the effect of the invention according to claim 2.
<Effect> It is possible to prevent a problem that the lower protruding portion is clogged by liquid fuel waxing or freezing in a cold region.
Since the lower protrusion-shaped portion (12a) includes the fuel drain device (13), the liquid fuel (5) accumulated in the lower protrusion-shaped portion (12a) can be discharged by the fuel drain device (13). In the case of shipping as a cold region specification, it is possible to prevent deficiencies that the normal temperature specification liquid fuel used in the pre-shipment test of the exhaust treatment device remains in the lower protrusion shape portion (12a), and in the cold region, the lower protrusion shape portion (12a). Can be prevented from clogging due to waxing or freezing of the liquid fuel (5).

(Invention of Claim 4)
The invention according to claim 4 has the following effects in addition to the effects of the invention according to any one of claims 1 to 3.
<Effect> It is possible to prevent the gas-liquid separation tank from clogging due to liquid fuel waxing or freezing in a cold region.
Since the liquid fuel reservoir (14a) of the gas-liquid separation tank (14) includes the fuel drain device (13), the liquid fuel (5) accumulated in the liquid fuel reservoir (14a) is discharged by the fuel drain device (13). When the engine is shipped as a cold region specification, it is possible to prevent the liquid fuel having the normal temperature specification used in the pre-shipment test of the exhaust treatment device from remaining in the gas-liquid separation tank (14) and to prevent the gas in the cold region. It is possible to prevent the liquid separation tank (14) from being clogged due to the waxing or freezing of the liquid fuel (5).

(Invention according to claim 5)
The invention according to claim 5 has the following effects in addition to the effects of the invention according to any one of claims 1 to 4.
<Effect> The fuel supply accuracy of the gas generation fuel supply pump can be increased.
Since the gas generating fuel supply passage (12) includes an air venting device (17) connected to the fuel inlet (2a) of the gas generating fuel supply pump (2), the air venting device (17) vents the air. The liquid fuel (5) can be filled in the gas generation fuel supply passage (12) up to the fuel inlet of the gas generation fuel supply pump (2), and the air to the gas generation fuel supply pump (2) can be filled. This prevents the fuel supply amount from the gas generation fuel supply pump (2) to the combustible gas generator (3) from fluctuating, and improves the fuel supply accuracy of the gas generation fuel supply pump (2). be able to.

It is a figure explaining the diesel engine which concerns on embodiment of this invention.

  FIG. 1 is a diagram illustrating a diesel engine according to an embodiment of the present invention. In the embodiment, a vertical in-line four-cylinder diesel engine will be described.

This engine includes an exhaust treatment device.
In the exhaust treatment device, the liquid fuel (5) is supplied to the combustible gas generator (3) through the gas generating fuel supply passage (12) by the gas generating fuel supply pump (2), and the combustible gas generator is supplied. In (3), the combustible gas (6) is generated from the liquid fuel (5), the combustible gas (6) is mixed into the engine exhaust (7), and the engine exhaust (7) is generated by the combustion heat of the combustible gas (6). ) Is heated, and the PM deposited on the DPF (4) by the heat of the exhaust (7) is configured to be removed by incineration of the engine.

  The gas generation fuel supply pump (2) is an electric pump. The combustible gas generator (3) includes a combustible gas generating catalyst (3a). The combustible gas generating 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). And an 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 arranged in the middle of the exhaust path (28) of the engine. The DOC (22) is accommodated in the exhaust treatment case (21) on the upstream side in the exhaust direction, and the DPF (4) is located on the downstream side. Is housed. DOC is an abbreviation for diesel oxidation catalyst, and DPF is an abbreviation for diesel particulate filter. The control device (23) is an engine ECU. ECU is an abbreviation for electronic control unit and is a microcomputer. The ignition device (30) is a glow plug.

The control device (23) is electrically connected to the sensors (24), (25), (26), the gas supply fuel supply pump (2), the blower (20), and the ignition device (30). Detection signals from the sensors (24), (25), and (26) are received by the control device (23), and based on the detection signals, a fuel supply pump for gas generation (2), a blower (20), and an ignition device (30). Is controlled by the control device (23).
Specifically, based on detection of the differential pressure between the inlet and outlet of the DPF (4) by the differential pressure sensor (26), the control device (23) estimates the amount of PM deposited on the DPF (4). When the PM accumulation value reaches a predetermined value, the gas generation fuel supply pump (2), the blower (20), and the ignition device (30) are controlled based on the command signal of the control device (23) to generate combustible gas. Liquid fuel (5) and air (29) are supplied to the vessel (3), and the liquid fuel (5) is oxidized by the combustible gas generating catalyst (3a) to become a combustible gas (6), and the exhaust path (28) The combustible gas (6) is catalytically combusted by the DOC (22), the temperature of the exhaust (7) is raised by the combustion heat, and PM deposited on the DPF (4) is incinerated and removed. , DPF (4) is regenerated.

  When the DOC inlet temperature is lower than the activation temperature of the DOC (22), the combustible gas (6) is ignited by the ignition device (30) and exhausted by the flame combustion of the combustible gas (6) (7). Is raised, and the DOC inlet temperature becomes the activation temperature of DOC (22). Further, the control device (23) controls the gas generation fuel supply pump (2) and the blower (20) so that the DPF inlet temperature becomes a predetermined PM incineration temperature, so that the combustible gas generator (3) is supplied. The supply amounts of liquid fuel (5) and air (29) are adjusted. Further, the combustible gas (6) is combusted by oxygen in the exhaust (7), but secondary air is supplied to the combustible gas (6) from the blower (20) in order to promote combustion.

This engine includes a fuel injection device.
As shown in FIG. 1, in the fuel injection device, the liquid fuel (5) in the fuel tank (1) is supplied to the fuel injection pump (9) by the fuel supply pump (8), and the liquid fuel is supplied 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) overflowing from the fuel injection pump (9) and the fuel injection valve (10) is supplied to the fuel return passage (11). ) To return to the fuel tank (1).

  The fuel supply pump (8) is a mechanical pump, is attached to the cylinder block (18), and is driven by a pump cam of a fuel injection cam shaft (not shown). The fuel injection pump (9) is a cam-driven plunger type row type pump, is attached to the cylinder block (18), and is driven by a fuel injection cam of a fuel injection cam shaft. 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 engine includes a gas-liquid separation tank (14), a fuel bypass passage (15), and a temperature-sensitive fuel valve (16). The gas-liquid separation tank (14) is a fuel injection pump ( 9) and the fuel recirculation passage (11) downstream of the fuel injection valve (10) in the fuel recirculation direction, and the fuel bypass passage (15) extends from the liquid fuel reservoir (14a) of the gas-liquid separation tank (14). Derived, bypassing the fuel tank (1), the leading end of the fuel bypass passage (15) is connected to the fuel passage (8a) between the fuel tank (1) and the fuel supply pump (8), and the fuel for gas generation The supply passage (12) is led out from the fuel bypass passage (15), and the temperature-sensitive fuel valve (16) is located downstream from the outlet of the gas generation fuel supply passage (12) in the fuel passage direction. If the temperature of the liquid fuel detected by the temperature-sensitive fuel valve (16) is higher than a predetermined value, the temperature-sensitive Ryoben (16) becomes a closed state, when less than the predetermined value, temperature sensitive fuel valve (16) is configured to be open.

  The temperature-sensitive fuel valve (16) is of a wax type, and when the detected liquid fuel temperature is equal to or higher than a predetermined value, the valve element is opened with the volume of liquefied wax. In the case of less than this, the valve body is closed due to a decrease in the volume of the solidified wax.

As shown in FIG. 1, the gas supply fuel supply passage (12) includes a lower protruding portion (12a), and the lower protruding portion (12a) is led downward from the fuel bypass passage (15), The gas generating fuel supply pump (2) is disposed downstream of the lower protruding portion (12a) in the fuel supply direction.
Both the lower protruding portion (12a) and the liquid fuel reservoir (14a) of the gas-liquid separation tank (14) are provided with a fuel drain device (13).
The gas generation fuel supply passage (12) includes an air venting device (17) connected to the fuel inlet (2a) of the gas generation fuel supply pump (2).
The lower protruding portion (12a) has a U-shaped lower protruding shape.
Both the fuel drain device (13) and the air vent device (17) are manually opened / closed cocks.

(1) Fuel tank
(2) Fuel supply pump for gas generation
(2a) Fuel inlet
(3) Combustible gas generator
(4) DPF
(5) Liquid fuel
(6) Combustible gas
(7) Engine exhaust
(8) Fuel supply pump
(8a) Fuel passage
(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 protruding part
(13) Fuel drain device
(14) Gas-liquid separation tank
(14a) Liquid fuel reservoir
(15) Fuel bypass passage
(16) Temperature sensitive fuel valve
(17) Air bleeding device

Claims (5)

The liquid fuel (5) is supplied to the combustible gas generator (3) by the gas generating fuel supply pump (2) through the gas generating fuel supply passage (12), and the liquid fuel (5) is liquidated by the combustible gas generator (3). Combustible gas (6) is generated from fuel (5), combustible gas (6) is mixed into engine exhaust (7), and engine exhaust (7) is heated by the combustion heat of combustible gas (6). In a diesel engine comprising an exhaust treatment device configured to incinerate and remove PM deposited on the DPF (4) by the heat of the engine exhaust (7),
The liquid fuel (5) in the fuel tank (1) is supplied to the fuel injection pump (9) by the fuel supply pump (8), and the liquid fuel (5) is supplied by the fuel injection pump (9) through the fuel injection pipe (9a). The liquid fuel (5) injected from the fuel injection valve (10) and overflowed from the fuel injection pump (9) and the fuel injection valve (10) is returned to the fuel tank (1) through the fuel return passage (11). Comprising a fuel injection device configured in
A gas-liquid separation tank (14), a fuel bypass passage (15), and a temperature-sensitive fuel valve (16) are provided. The gas-liquid separation tank (14) is more than the fuel injection pump (9) and the fuel injection valve (10). The fuel return passage (11) is provided downstream of the fuel return direction, and the fuel bypass passage (15) is led out from the liquid fuel reservoir (14a) of the gas-liquid separation tank (14) and bypasses the fuel tank (1). The lead-out end of the fuel bypass passage (15) is connected to the fuel passage (8a) between the fuel tank (1) and the fuel supply pump (8), and the gas generation fuel supply passage (12) is connected to the fuel bypass passage (15). The temperature-sensitive fuel valve (16) is provided in the fuel bypass passage (15) downstream of the outlet position of the gas generation fuel supply passage (12) in the fuel passage direction, and the temperature-sensitive fuel valve (16 ), The temperature-sensitive fuel valve (16) is closed and the predetermined temperature is exceeded. Less than in the case of the temperature sensitive fuel valve (16) is configured to be opened, diesel engine, characterized in that. The diesel engine according to claim 1,
The gas generation fuel supply passage (12) includes a lower protruding portion (12a), and the lower protruding portion (12a) is led downward from the fuel bypass passage (15) and then inverted downward. A diesel engine characterized in that the gas generating fuel supply pump (2) is arranged downstream of the lower protruding portion (12a) in the fuel supply direction. The diesel engine according to claim 2,
A diesel engine characterized in that the lower protruding portion (12a) includes a fuel drain device (13). In the diesel engine according to any one of claims 1 to 3,
A diesel engine characterized in that the liquid fuel reservoir (14a) of the gas-liquid separation tank (14) includes a fuel drain device (13). In the diesel engine according to any one of claims 1 to 4,
A diesel engine characterized in that the gas generation fuel supply passage (12) includes an air venting device (17) connected to a fuel inlet (2a) of the gas generation fuel supply pump (2).

Images