JP2015063975A - Engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine capable of preventing freezing of a blow-by gas outlet in cold.SOLUTION: In an engine, a low-pressure EGR outlet 5b opened by a suction pipe 9 is provided at a terminal end 5a of a low-pressure EGR passage 5, and a blow-by gas outlet 19b opened by the suction pipe 9 is provided at a terminal end 19a of a blow-by gas passage 19. The low-pressure EGR outlet 5b and the blow-by gas outlet 12b are arranged at opposed positions across a passage 9 in the suction pipe 9. Low-pressure EGR gas 20 flows from the low-pressure EGR outlet 5b toward the blow-by gas outlet 12b during a predetermined period among engine cold start and warming periods including a cold start period of the engine and a warming period after the cold start period.

Description

  The present invention relates to an engine, and more particularly to an engine capable of preventing icing at a blow-by gas outlet during cold weather.

  Conventionally, the engine has an engine body, a DPF case, a high pressure EGR path, a supercharger, and a low pressure EGR path, and the high pressure EGR path is interposed between the exhaust manifold and the intake manifold. An exhaust discharge path is derived, an intake pipe is led out from the air compressor of the turbocharger, a low pressure EGR path is interposed between the exhaust discharge path of the DPF case and the intake pipe, and a low pressure EGR cooler is provided in the low pressure EGR path In some cases, a low-pressure EGR outlet opening at the end of the low-pressure EGR path is provided by an intake pipe, and a blow-by gas outlet opening at the end of the blow-by gas passage is provided by an intake pipe (see, for example, Patent Document 1). ).

  According to this type of engine, there is an advantage that blow-by gas is recirculated to intake air and re-combusted to suppress blow-by gas discharge.

  However, the thing of this patent document 1 has the problem that icing of the blow-by gas exit at the time of cold cannot be prevented.

JP 2012-241598 A (see FIG. 1)

<Problem> It is impossible to prevent freezing at the outlet of the blow-by gas during cold weather.
In Patent Document 1, since the low-temperature intake air passes through the intake pipe during the cold start-up period of the engine and the subsequent warm-up operation period, the temperature of the blow-by gas outlet is lowered. Can't prevent freezing.

  The subject of this invention is providing the engine which can prevent the freezing of the blowby gas exit at the time of cold.

Invention specific matters of the invention according to claim 1 are as follows.
As illustrated in FIG. 1 and FIG. 2, an engine body (1), a DPF case (2), a high pressure EGR path (3), a supercharger (4), and a low pressure EGR path (5) are provided. ,
A high pressure EGR path (3) is interposed between the exhaust manifold (6) and the intake manifold (7),
The exhaust discharge path (8) is derived from the DPF case (2), the intake pipe (9) is derived from the air compressor (4a) of the supercharger (4), and the low pressure EGR path (5) is connected to the DPF case (2). A low pressure EGR cooler (10) is provided in the low pressure EGR path (5), and is interposed between the exhaust discharge path (8) and the intake pipe (9).
As illustrated in FIG. 3, a low pressure EGR outlet (5b) opened by an intake pipe (9) is provided at a terminal end (5a) of the low pressure EGR path (5), and a terminal end (19a) of the blow-by gas passage (19) is provided. ) Provided with a blow-by gas outlet (19b) that opens at the intake pipe (9).
As illustrated in FIG. 3, the low-pressure EGR outlet (5b) and the blow-by gas outlet (12b) are disposed at positions facing each other across the intake pipe passage (9) of the intake pipe (9).
The low-pressure EGR gas (20) is directed from the low-pressure EGR outlet (5b) to the blow-by gas outlet (12b) during a predetermined period of the engine cold-start warm-up period consisting of the engine cold-start period and the subsequent warm-up period. An engine characterized by being configured to flow.

(Invention of Claim 1)
The invention according to claim 1 has the following effects.
<Effect> It is possible to prevent freezing in the vicinity of the blow-by gas outlet during cold weather.
As illustrated in FIG. 3, from a low pressure EGR outlet (5b) to a blow-by gas outlet (12b) for a predetermined period of the engine cold start warm-up period consisting of an engine cold start period and a subsequent warm-up period. Therefore, the blow-by gas outlet (12b) is heated by the heat of the low-pressure EGR gas (20), and the blow-by gas outlet (12b) is frozen at the time of cold. Can be prevented.

(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 clogging of the low-pressure EGR outlet.
As illustrated in FIG. 3, the intake pipe (9) includes an inclined intake pipe portion (9a) led out obliquely upward, and a low pressure EGR outlet ( 5b), the blow-by gas outlet (19b) is arranged on the upper peripheral wall (9d) of the inclined intake pipe portion (9), and the lower peripheral wall (9c) located directly below the blow-by gas outlet (19b) Since the low pressure EGR outlet (5b) is disposed at a position higher than the position directly below (9e), water, oil, and carbon in the blowby gas (22) flowing out from the blowby gas outlet (19b) are discharged from the low pressure EGR outlet (5b). ) And the clogging of the low pressure EGR outlet (5b) can be prevented.

It is a rear view of the engine which concerns on embodiment of this invention. It is a right view of the engine of FIG. FIG. 2 is a longitudinal side view of a downward convex bypass path, a low pressure EGR valve case, and an intake pipe used in the engine of FIG. 1. It is a top view of the engine of FIG. It is a front view of the engine of FIG. It is a left view of the engine of FIG. It is the perspective view which looked down at the engine of FIG. 1 from the right front.

  FIGS. 1-7 is a figure explaining the engine which concerns on embodiment of this invention, and this embodiment demonstrates a water-cooled vertical in-line multicylinder diesel engine.

The outline of the engine body is as follows.
As shown in FIGS. 1 and 2, the cylinder head (15) is assembled to the upper part of the cylinder block (23), the cylinder head cover (16) is assembled to the upper part of the cylinder head (15), and the cylinder block (23) A water pump case (24) is assembled at the front part, a flywheel housing (25) is arranged at the rear part of the cylinder block (23), a flywheel (12) is accommodated therein, and a lower part of the cylinder block (23). An oil pan (26) is assembled to the body.
An exhaust manifold (6) is assembled on one side of the cylinder head (15), and an intake manifold (7) is assembled on the other side.

The outline of this engine is as follows.
As shown in FIGS. 1 and 2, an engine body (1), a DPF case (2), a high pressure EGR path (3), a supercharger (4), and a low pressure EGR path (5) are provided. Yes.
A high pressure EGR path (3) is interposed between the exhaust manifold (6) and the intake manifold (7).
The exhaust discharge path (8) is derived from the DPF case (2), the intake pipe (9) is derived from the air compressor (4a) of the supercharger (4), and the low pressure EGR path (5) is connected to the DPF case (2). The low pressure EGR cooler (10) is provided in the low pressure EGR path (5). The low pressure EGR path (5) is interposed between the exhaust discharge path (8) and the intake pipe (9).

The DPF case (2) is mounted on the engine body (1).
The installation direction of the crankshaft (11) is the front-rear direction, the flywheel (12) side is the rear side, and the width direction of the engine body (1) is the lateral direction.
As shown in FIGS. 1 and 2, the low pressure EGR path (5) includes a rear path portion (13) along the rear side of the engine body (1), and an engine body (1) side of the exhaust manifold (6) side. And a lateral path portion (14) along
As a result, while the DPF case (2) has a compact shape mounted on the engine body (1), the path length of the low-pressure EGR path (5) is reduced to the rear path part (13) and the side path part (14 ), The heat dissipation from the parts other than the low pressure EGR cooler (10) is increased, the dependency of the heat dissipation on the low pressure EGR cooler (10) is reduced, and the low pressure EGR cooler (10) is reduced in size. be able to.

As shown in FIGS. 1 and 2, the low-pressure EGR cooler (10) is disposed in the lateral path portion (14) of the low-pressure EGR path (5) at a position lower than the upper surface (15a) of the cylinder head (15). ing.
A portion near the start end (13a) of the rear path portion (13) of the low pressure EGR path (5) is disposed immediately behind the cylinder head cover (16), and a portion near the end (13b) of the rear path portion (13) is The end portion (13c) of the rear path portion (13) is connected to the low pressure EGR cooler (10) by bending downward from the start end portion (13a).
As a result, the path length of the rear path portion (13) is increased by bending the end portion (13b), the heat dissipation performance of the rear path portion (13) is increased, and the dependency of heat dissipation on the low pressure EGR cooler (10) is increased. The degree is reduced, and the low pressure EGR cooler (10) can be reduced in size.

As shown in FIG. 2, engine coolant that passes through the coolant jacket of the cylinder head (15) is used as the refrigerant of the low-pressure EGR cooler (10) that is lower than the cylinder head (15).
As a result, air or water vapor that tends to accumulate in the low-pressure EGR cooler (10) can easily escape to the cooling water jacket of the cylinder head (15), and the cooling performance of the low-pressure EGR cooler (10) can be maintained high.

As shown in FIG. 1, the exhaust discharge path (8) is led out from the DPF case end (2a) on the intake manifold (7) side, and the low pressure EGR path from the exhaust discharge path (8) on the intake manifold (7) side. (5) The rear path portion (13) is branched.
As a result, the path length of the rear path portion (13) extending from the exhaust discharge path (8) on the intake manifold (7) side to the lateral path portion (14) on the exhaust manifold (6) side is increased. The heat dissipation of the path portion (13) is increased, the dependency of the heat dissipation on the low pressure EGR cooler (10) is reduced, and the low pressure EGR cooler (10) can be downsized.

As shown in FIG. 4, the DPF case (2) is disposed above the engine body (1),
When viewed from directly above, the exhaust discharge path (8) and the rear path part (13) of the low-pressure EGR path (5) are arranged below the DPF case (2) at a position overlapping the DPF case (2). ing.
As a result, the exhaust discharge path (8) and the rear path part (13) of the low pressure EGR path (5) do not protrude beyond the rear side of the DPF case (2), and the overall length of the engine is kept short. can do.

As shown in FIG. 4, the DPF case (2) is disposed above the engine body (1), and when viewed from directly above, a part of the lateral path portion (14) of the low pressure EGR path (5) is part of the DPF case. It is arranged at a position overlapping (2).
As a result, a part of the lateral path portion (14) does not protrude more laterally than the DPF case (2), and the entire width of the engine can be kept short.

As shown in FIG. 4, a supercharger (4) is attached to the exhaust manifold (6), and a part of the side path portion (14) of the low pressure EGR path (5) is supercharged when viewed from directly above. It is arranged at a position overlapping (4).
As a result, a part of the lateral path portion (14) does not protrude greatly laterally from the supercharger, and the entire width of the engine can be kept short.

As shown in FIG. 4, when viewed from directly above, the high-pressure EGR path (3) is disposed below the DPF case (2) at a position overlapping the DPF case (2).
As a result, the high pressure EGR path (3) does not protrude beyond the DPF case (2) to the rear and side, and the overall length and width of the engine can be kept short.

As shown in FIG. 2 and FIG. 3, the lateral path portion (14) of the low pressure EGR path (5) is provided with a downward convex bypass path portion (14a) that once descends and rises, and this downward convex bypass path portion ( The upper end portion (14b) of 14a) is connected to the intake pipe (9).
As a result, the path length of the lateral path portion (14) is increased by the downward convex detour path portion (14a), the dependence of the heat radiation on the low pressure EGR cooler (10) is reduced, and the low pressure EGR cooler (10) is reduced in size. Can be

As shown in FIGS. 2 and 3, the low pressure EGR cooler (10) is disposed upstream of the downward convex detour path portion (14a), and the low pressure EGR is disposed in the ascending path portion (14c) of the downward convex bypass path portion (14a). A valve case (17) is arranged, and the lowest portion (14d) of the downward convex detour path portion (14a) is a condensed water reservoir (18) of condensed water flowing out from the low pressure EGR cooler (10) and the low pressure EGR valve case (17). It is said that.
As a result, the condensed water containing the sulfuric acid component does not easily accumulate in the low pressure EGR cooler (10) and the low pressure EGR valve case (17), and the corrosion in the low pressure EGR cooler (10) and the low pressure EGR valve case (17) is suppressed. Can do.

As shown in FIGS. 2 and 3, the low-pressure EGR valve case (17) is inclined downwardly toward the side where the condensed water reservoir (18) is located.
Thereby, the condensed water (21) containing a sulfuric acid component is hard to accumulate in the low pressure EGR valve case (17), and corrosion in the low pressure EGR valve case (17) can be suppressed.

As shown in FIGS. 2 and 3, the lowest part (14d) of the downward convex detour path part (14a) is arranged at a position lower than the exhaust manifold (6).
The supercharger (4) is arranged on the upper portion of the exhaust manifold (6), and the intake pipe (9) is provided with an inclined intake pipe portion (9a) led out obliquely upward, and the inclined intake pipe portion (9a) has a low pressure. The terminal part (5a) of the EGR path (5) is connected.
As a result, the inclined intake pipe portion (9a) led obliquely upward increases the path length of the low pressure EGR path (5), enhances heat dissipation from portions other than the low pressure EGR cooler (10), and reduces the low pressure EGR. The dependence of heat dissipation on the cooler (10) is reduced, and the low-pressure EGR cooler (10) can be downsized.

As shown in FIGS. 2 and 3, the upward path portion (14c) of the downward convex detour path portion (14a) is bent along the shape of the intake pipe (9).
As a result, the bent path shape increases the path length of the ascending path portion (14c), increases the heat dissipation from portions other than the low pressure EGR cooler (10), and decreases the dependence of the heat dissipation on the low pressure EGR cooler (10). In addition, the low pressure EGR cooler (10) can be reduced in size.

As shown in FIG. 4, as viewed from directly above, a part of the downward convex detour path portion (14a) is arranged below the supercharger (4) at a position overlapping the supercharger (4).
Thereby, a part of the downward convex detour path portion (14a) does not protrude greatly to the side of the supercharger (4), and the entire width of the engine can be kept short.

As shown in FIG. 4, as viewed from directly above, a part of the downward convex detour path portion (14a) is disposed below the intake pipe (9) at a position overlapping the intake pipe (9).
As a result, a part of the downward convex detour path portion (14a) does not overhang laterally from the intake pipe (9), and the entire width of the engine can be kept short.

As shown in FIG. 3, a low pressure EGR outlet (5b) opened by an intake pipe (9) is provided at a terminal portion (5a) of a low pressure EGR path (5), and a terminal portion (19a) of a blow-by gas passage (19). Is provided with a blow-by gas outlet (19b) opened at the intake pipe (9), and the low-pressure EGR outlet (5b) and the blow-by gas outlet (12b) sandwich the intake pipe inner passage (9) of the intake pipe (9). It is arranged at the opposite position.
The low-pressure EGR gas (20) is directed from the low-pressure EGR outlet (5b) to the blow-by gas outlet (12b) during a predetermined period of the engine cold-start warm-up period consisting of the engine cold-start period and the subsequent warm-up period. It is configured to flow out.
Thereby, the blow-by gas outlet (12b) is heated by the heat of the low-pressure EGR gas (20), and freezing of the blow-by gas outlet (12b) at the time of cold can be prevented.

As shown in FIG. 3, the intake pipe (9) includes an inclined intake pipe portion (9a) led out obliquely upward, and a low-pressure EGR outlet (5b) is provided on a lower peripheral wall (9c) of the inclined intake pipe portion (9a). ) And a blow-by gas outlet (19b) is disposed on the upper peripheral wall (9d) of the inclined intake pipe portion (9).
The low-pressure EGR outlet (5b) is arranged at a position higher than the position (9e) directly below the lower peripheral wall (9c) located directly below the blow-by gas outlet (19b).
As a result, water, oil, or carbon in the blow-by gas (22) flowing out from the blow-by gas outlet (19b) is unlikely to enter the low-pressure EGR outlet (5b), and clogging of the low-pressure EGR outlet (5b) can be prevented. .

As shown in FIG. 1, the exhaust discharge pipe (2b) of the DPF case (2) that constitutes the start end of the exhaust discharge path (8) and branches the rear path portion (13) of the low pressure EGR path (5) is , Tilted away from the exhaust manifold (6) side.
As a result, the path length of the rear path portion (13) becomes longer, the heat dissipation performance of the rear path portion (13) increases, the dependence of the heat dissipation on the low pressure EGR cooler (10) decreases, and the low pressure EGR cooler ( 10) can be reduced in size.
An exhaust duct (not shown) constituting the exhaust discharge path (8) is connected to the tip of the exhaust discharge pipe (2b), and an SCR catalyst case is connected to the tip of the exhaust duct.
In the DPF case (2), a DOC (32) is disposed upstream and a DPF (33) is disposed downstream. DOC is a diesel oxidation catalyst, and DPF is a diesel particulate filter.
The SCR catalyst is a selective reduction type NO _X catalyst.

As shown in FIGS. 1 and 2, the high pressure EGR path (3) includes a rear high pressure EGR cooler (27) just behind the cylinder head (15) and a lateral high pressure EGR cooler (28) directly beside the cylinder head (15). And. Both the rear high pressure EGR cooler (27) and the horizontal high pressure EGR cooler (28) are disposed at a position lower than the upper surface (15a) of the cylinder head (15), and the coolant is used as the coolant and the coolant of the cylinder head (15). Engine cooling water that passes through the jacket is used.
For this reason, air or water vapor that tends to accumulate in the rear high-pressure EGR cooler (27) or the horizontal high-pressure EGR cooler (28) can easily escape to the cooling water jacket of the cylinder head (15), and the cooling performance of the low-pressure EGR cooler (10). Can be kept high.
Of the high pressure EGR path (3), the pipe portion excluding the rear high pressure EGR cooler (27) and the lateral high pressure EGR cooler (28), and among the low pressure EGR path (5), the low pressure EGR cooler (10) and the low pressure EGR valve The pipe portion excluding the case (17) is made of a metal pipe that easily dissipates heat.

An EGR valve (17a) is accommodated in the low pressure EGR valve case (17) shown in FIG. 3, and the periphery of the valve stem (17b) is sealed with a stem seal (17c).
The EGR valve (17a), the valve stem (17b), and the stem seal (17c) are all inclined downwardly toward the side where the condensed water reservoir (18) is located, like the low pressure EGR valve case (17). Yes.
As a result, even if condensed water (21) containing a sulfuric acid component adheres to the EGR valve (17a), the valve stem (17b), and the stem seal (17c), the condensed water (21) is moved to the condensed water reservoir (18) side. Easy to flow down.
A valve actuator (29) is attached to the front side of the EGR valve case (17), and the EGR valve (17a) is opened and closed by the valve actuator (29).
Similarly to the low-pressure EGR valve case (17), the valve actuator (29) is also inclined downward toward the side where the condensed water reservoir (18) is located.

  As shown in FIG. 2, an oil separator (19c) is provided in the middle of the blow-by gas passage (19). As shown in FIG. 4, the oil separator (19c) is arranged directly above the cylinder head cover (16). ing.

  As shown in FIG. 6, a common rail system (30) and an electronic throttle device (31) are disposed on the intake manifold (7) side of the engine body. As shown in FIG. 4, the electronic throttle device (31) is disposed directly above the intake manifold (7).

(1) Engine body
(2) DPF case
(3) High pressure EGR route
(4) Turbocharger
(4a) Air compressor
(5) Low pressure EGR route
(5a) Terminal part
(5b) Low pressure EGR outlet
(6) Exhaust manifold
(7) Intake manifold
(8) Exhaust discharge route
(9) Intake pipe
(9a) Inclined intake pipe part
(9b) Internal passage
(9c) Lower wall
(9d) Upper peripheral wall
(9e) Directly below position
(19) Blowby gas passage
(19a) Termination
(19b) Blowby gas outlet
(20) Low pressure EGR gas

Claims (2)

An engine body (1), a DPF case (2), a high pressure EGR path (3), a supercharger (4), and a low pressure EGR path (5);
A high pressure EGR path (3) is interposed between the exhaust manifold (6) and the intake manifold (7),
The exhaust discharge path (8) is derived from the DPF case (2), the intake pipe (9) is derived from the air compressor (4a) of the supercharger (4), and the low pressure EGR path (5) is connected to the DPF case (2). A low pressure EGR cooler (10) is provided in the low pressure EGR path (5), and is interposed between the exhaust discharge path (8) and the intake pipe (9).
A low-pressure EGR outlet (5b) that opens at the intake pipe (9) is provided at the end portion (5a) of the low-pressure EGR path (5), and the intake pipe (9) is provided at the end portion (19a) of the blow-by gas passage (19). In an engine provided with an open blow-by gas outlet (19b),
The low pressure EGR outlet (5b) and the blow-by gas outlet (12b) are arranged at positions facing each other across the intake pipe passage (9) of the intake pipe (9),
The low-pressure EGR gas (20) is directed from the low-pressure EGR outlet (5b) to the blow-by gas outlet (12b) during a predetermined period of the engine cold-start warm-up period consisting of the engine cold-start period and the subsequent warm-up period. An engine characterized by being configured to flow. The engine according to claim 1,
The intake pipe (9) is provided with an inclined intake pipe portion (9a) led out obliquely upward, and a low pressure EGR outlet (5b) is disposed on a lower peripheral wall (9c) of the inclined intake pipe portion (9a), and inclined intake air A blow-by gas outlet (19b) is arranged on the upper peripheral wall (9d) of the pipe portion (9),
An engine characterized in that the low-pressure EGR outlet (5b) is arranged at a position higher than a position (9e) directly below the lower peripheral wall (9c) located directly below the blow-by gas outlet (19b).

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