JP2021008879A - engine - Google Patents

Abstract

To provide an engine increased in heat quantity of an exhaust gas capable of being utilized in an exhaust passage.SOLUTION: An engine includes an exhaust manifold 3 as an exhaust passage component 1 constituting an exhaust passage. The exhaust manifold is composed of iron-based metal as a material, and includes a heat-storage swollen portion 3m swollen from a thick wall 3k to the outside, and an oxide film 1b of triiron tetraoxide formed on a swollen face 3n of the heat-storage swollen portion. The heat-storage swollen portion is preferably swollen from a thick wall part 3ka against which the exhaust gas flowing out from an exhaust port 6c of a cylinder head 6 is blown, to the outside. The exhaust manifold preferably includes the oxide film of triiron tetraoxide formed on an outer face 1c excluding the swollen face, of the heat-storage swollen portion.SELECTED DRAWING: Figure 1

Description

The present invention relates to an engine, and more particularly to an engine in which the amount of heat of exhaust gas available in an exhaust passage is large.

Conventionally, there is an exhaust passage component provided with an exhaust manifold as an exhaust passage component (see, for example, Patent Document 1).

JP-A-2014-77377

<< Problem >> The amount of heat of the exhaust that can be used in the exhaust passage is reduced.
In the engine of this patent document, the exhaust manifold is water-cooled and a large amount of heat is released from the exhaust to the outside of the exhaust manifold, so that the amount of heat available in the exhaust passage is reduced.

An object of the present invention is to provide an engine having a large amount of heat of exhaust gas that can be used in an exhaust passage.

The main configurations of the present invention are as follows.
As illustrated in FIGS. 1 (A) to 1 (E) and FIGS. 2 (A) to 2 (E), an exhaust manifold (3) is provided as an exhaust passage component (1) constituting the exhaust passage, and the exhaust manifold (3) is provided. ) Is a heat storage bulging portion (3 m) of an iron-based metal that bulges outward from the meat wall (3k) and a tritetraoxide formed on the bulging surface (3n) of the heat storage bulging portion (3 m). An engine characterized by having an iron oxide film (1b).

In the present invention, the following effects can be obtained.
<< Effect 1 >> The amount of heat of the exhaust that can be used in the exhaust passage increases.
The exhaust heat stored in the heat storage bulge (3 m) is generated from the bulge surface (3n) of the exhaust manifold (3) due to the heat insulating function of the oxide film (1b) of triiron tetroxide, which has extremely low thermal conductivity. It is difficult to dissipate heat, and the amount of heat of the exhaust that can be used in the exhaust passage increases.
<< Effect 2 >> The generation of red rust due to exhaust heat on the bulging surface (3n) of the heat storage bulging portion (3m) is suppressed.
The rust preventive action of the oxide film (1b) of triiron tetroxide suppresses the generation of red rust due to exhaust heat on the bulging surface (3n) of the heat storage bulging portion (3m).
<< Effect 3 >> Thermal deterioration due to exhaust heat from the bulging surface (3n) of the heat storage bulging portion (3m) is unlikely to occur.
Since the oxide film (1b) of triiron tetroxide has excellent heat resistance and is less likely to crack or discolor, thermal deterioration due to exhaust heat of the bulging surface (3n) of the bulging portion (3m) for heat storage is unlikely to occur.
<< Effect 4 >> The airtightness between the exhaust manifold (3) and the cylinder head (6) is high.
The wall (3k) of the exhaust manifold (3) has increased rigidity at the heat storage bulging portion (3 m) and is less likely to cause thermal strain. The exhaust manifold (3) and the cylinder illustrated in FIGS. 1 (A) and 1 (C) The heads (6) are highly sealed between each other.

In the figure explaining the exhaust manifold used in the engine which concerns on embodiment of this invention, FIG. 1A is a horizontal sectional plan view, FIG. 1B is a sectional view taken along line BB of FIG. 1A, and FIG. (C) is a sectional view taken along line CC of FIG. 1 (B), FIG. 1 (D) is an enlarged sectional view taken along line DD of FIG. 1 (A), and FIG. 1 (E) is E of FIG. 1 (A). -E line cross-sectional enlarged view. 2 (A) is a plan view, FIG. 2 (B) is a view taken in the direction of arrow B of FIG. 1 (A), and FIG. 2 (C) is a view of FIG. 1 (B). The C-direction arrow view, FIG. 2 (D) is the D-direction arrow view of FIG. 1 (B), and FIG. 2 (E) is the E-direction arrow view of FIG. 1 (C). 3A is a side view, FIG. 3B is a view taken along the line B of FIG. 3A, and FIG. 3C is a view for explaining an exhaust relay pipe used in the engine according to the embodiment of the present invention. ) Is the C-direction arrow view of FIG. 3 (A), FIG. 3 (D) is the D-direction arrow view of FIG. 3 (A), and FIG. 3 (E) is the E-direction arrow view of FIG. 3 (D). is there. It is a figure explaining the assembled state of the exhaust passage component of the engine which concerns on embodiment of this invention, FIG. 4A is a side view of the exhaust passage, FIG. 4B is the line BB of FIG. 4A. An enlarged cross-sectional view, FIG. 4 (C) is an enlarged cross-sectional view taken along line CC of FIG. 4 (A), FIG. 4 (D) is an enlarged cross-sectional view taken along line DD of FIG. 4 (A), and FIG. FIG. 4 (A) is an enlarged view of a cross section taken along line EE, and FIG. 4 (F) is an enlarged view of an enlarged cross section taken along line EF of FIG. 4 (A). It is a side view of the engine which concerns on embodiment of this invention. It is a front view of the engine of FIG.

1 to 6 are views for explaining an engine according to an embodiment of the present invention.
In this embodiment, a water-cooled vertical in-line multi-cylinder diesel engine will be described.

As shown in FIGS. 5 and 6, this engine has a cylinder block (7), a cylinder head (6) assembled on the upper part of the cylinder block (7), and a cylinder assembled on the upper part of the cylinder head (6). The front cover (10) assembled to the front part of the cylinder block (7) and the engine arranged in front of the cylinder head (6) with the erection direction of the head cover (8) and the crank shaft (9) in the front-rear direction. It includes a cooling fan (11), a fly wheel (12) arranged behind the cylinder block (7), and an oil pan (13) assembled to the lower part of the cylinder block (7).
The crankshaft (9) is cranked by the starter motor (22). The engine cooling fan (11) is driven from the crankshaft (9) via the belt transmission device (19). An oil filter (21) is attached to the front cover (10) via an oil cooler (20).
The engine is equipped with an intake system, a fuel supply system and an exhaust system.

As shown in FIGS. 5 and 6, the intake device includes an intake pipe (14), an air compressor housing (4i) of a supercharger (4), a supercharge pipe (15), and an intake manifold (16). , Supply intake air to a cylinder (not shown) in the cylinder block (7). A compressor wheel (not shown) is housed in the air compressor housing (4i). As shown in FIG. 6, the intake manifold (16) is arranged on one lateral side of the cylinder head (6), with the width direction of the engine orthogonal to the front-rear direction as the lateral direction.

As shown in FIG. 6, the fuel supply device is arranged on the lateral side of the engine in which the intake manifold (16) is arranged, and the fuel injection pump (17), the fuel injection pipe (18), and the fuel injection valve ( (Not shown) to supply fuel to the cylinder.
As shown in FIG. 5, the exhaust device includes an exhaust manifold (3), an exhaust turbine housing (4a) of a supercharger (4), and an exhaust relay pipe (5), and exhausts exhaust gas from a cylinder. A turbine wheel (not shown) is housed in the exhaust turbine housing (4a). As shown in FIG. 6, the exhaust manifold (3) is attached to the lateral other side of the cylinder head (6) on the side opposite to the lateral one side on which the intake manifold (16) is arranged.

As shown in FIGS. 1 (A) to 1 (E) and FIGS. 2 (A) to 2 (E), this engine includes an exhaust manifold (3) as an exhaust passage component (1) constituting the exhaust passage and exhausts. The manifold (3) was formed on a heat storage bulge (3 m) of an iron-based metal that bulges outward from the meat wall (3 k) and a bulge surface (3 n) of the heat storage bulge (3 m). It has an oxide film (1b) of triiron tetroxide.

Therefore, the following effects can be obtained with this engine.
In this engine, the exhaust heat stored in the heat storage bulge (3 m) is the bulge surface of the exhaust manifold (3) due to the heat insulating function of the oxide film (1b) of triiron tetroxide, which has extremely low thermal conductivity. It is difficult to dissipate heat from 3n), and the amount of heat of the exhaust that can be used in the exhaust passage increases.
Therefore, this engine has good fuel economy and high output.
Further, in this engine, the rust preventive action of the oxide film (1b) of triiron tetroxide suppresses the generation of red rust due to the exhaust heat on the bulging surface (3n) of the heat storage bulging portion (3m).
Further, in this engine, the oxide film (1b) of triiron tetroxide has excellent heat resistance and is less likely to crack or discolor. Therefore, thermal deterioration due to exhaust heat of the bulging surface (3n) of the bulging portion (3m) for heat storage. Is unlikely to occur.
Further, in this engine, the wall (3k) of the exhaust manifold (3) has increased rigidity at the heat storage bulging portion (3 m), and thermal strain is unlikely to occur. Therefore, the exhaust manifold (A) and (C) shown in FIGS. The seal between the (3) and the cylinder head (6) is high.

The meat wall (3k) of the exhaust manifold (3) is made of an iron-based metal material, and the heat storage bulge (3 m) has the material of the meat wall (3k) of the exhaust manifold (3) on the outside. The bulging part, the meat wall (3k) of the exhaust manifold (3) and the bulging part for heat storage (3m) are integrally molded products of continuous iron-based materials. Cast iron was used as the material for the iron-based metal, but steel can also be used. Further, triiron tetroxide has a thermal conductivity of only 1/100 (1/100) and a density of about 5/8 (5/8) of ordinary iron.

In this engine, as shown in FIGS. 1 (A) and 1 (C), the heat storage bulge (3 m) is a wall portion (3 ka) to which the exhaust gas flowing out from the exhaust port (6 c) of the cylinder head (6) is blown. ) And bulge outward.
Therefore, in this engine, the heat storage property of the heat storage bulge (3 m) is high.
As shown in FIG. 1 (B), the cylinder head (3) is viewed in a direction parallel to the central axis (6d) of the outlet portion of the exhaust port (6c) or in a direction orthogonal to the lateral wall surface of the cylinder head (3). ) Is viewed from the side, the heat storage bulge (3 m) is arranged at a position overlapping the exhaust port (6c).

In this engine, as shown in FIGS. 1 (A) to 1 (E) and FIGS. 2 (A) to 2 (E), the exhaust manifold (3) is other than the bulging surface (3n) of the heat storage bulging portion (3 m). It is provided with an oxide film (1b) of triiron tetroxide formed on the outer surface (1c) of the meat wall (3k) of the iron-based metal.

Therefore, the following effects can be obtained with this engine.
The exhaust heat stored in the wall (3k) of the exhaust manifold (3) is stored in the wall (3k) of the exhaust manifold (3) due to the heat insulating function of the oxide film (1b) of triiron tetroxide, which has extremely low thermal conductivity. ) Is difficult to dissipate heat from the outer surface (1c), so that the amount of heat of the exhaust that can be used in the exhaust passage increases.
Further, the rust preventive action of the oxide film (1b) of triiron tetroxide suppresses the generation of red rust due to the exhaust heat on the outer surface (1c) of the meat wall (3k) of the exhaust manifold (3).
Further, since the oxide film (1b) of triiron tetroxide has excellent heat resistance and is less likely to crack or discolor, thermal deterioration due to exhaust heat on the outer surface (1c) of the wall (3k) of the exhaust manifold (3) is caused. It's hard to happen.

As shown in FIG. 4A, this engine includes an exhaust turbine housing (4a) of a supercharger (4) as an exhaust passage component (1), and the exhaust turbine housing (4a) is made of iron-based metal. It is provided with an oxide film (1b) of triiron tetroxide formed on the outer surface (1c) of the meat wall.

Therefore, the following effects can be obtained with this engine.
The exhaust heat stored in the exhaust turbine housing (4a) is generated by the heat insulating function of the oxide film (1b) of triiron tetroxide, which has extremely low thermal conductivity, on the outer surface (1c) of the wall of the exhaust turbine housing (4a). Since it is difficult to dissipate heat from the exhaust, the amount of heat of the exhaust that can be used in the exhaust passage increases. Further, the rust preventive action of the oxide film (1b) of triiron tetroxide suppresses the generation of red rust on the outer surface (1c) of the meat wall of the exhaust turbine housing (4a) due to the exhaust heat.
Further, since the oxide film (1b) of triiron tetroxide has excellent heat resistance and is less likely to be cracked or discolored, thermal deterioration due to exhaust heat on the outer surface (1c) of the wall of the exhaust turbine housing (4a) is unlikely to occur. ..

As shown in FIGS. 3A to 3E, this engine includes an exhaust relay pipe (5) as an exhaust passage component (1), and the exhaust relay pipe (5) is made of an iron-based metal wall. It is provided with an oxide film (1b) of triiron tetroxide formed on the outer side surface (1c).
Therefore, the exhaust heat stored in the exhaust relay pipe (5) is the outer surface of the wall of the exhaust relay pipe (5) due to the heat insulating function of the oxide film (1b) of triiron tetroxide, which has extremely low thermal conductivity. Since it is difficult to dissipate heat from (1c), the amount of heat of the exhaust that can be used in the exhaust passage increases.
Further, the rust preventive action of the oxide film (1b) of triiron tetroxide suppresses the generation of red rust due to the exhaust heat on the outer surface (1c) of the wall of the exhaust relay pipe (5).
Further, since the oxide film (1b) of triiron tetroxide has excellent heat resistance and is less likely to be cracked or discolored, thermal deterioration due to exhaust heat on the outer surface (1c) of the wall of the exhaust relay pipe (5) is unlikely to occur. ..

In this engine, as described above, the iron-based metal is cast iron.
Therefore, in this engine, the heat storage bulging portion (3 m) can be easily molded by casting.

As shown in FIG. 4A, this engine is provided with a supercharger (4) on the exhaust downstream side of the exhaust manifold (3).
In this engine, as shown in FIGS. 1 (A) to 1 (E) and FIGS. 2 (A) to 2 (E), the heat storage function of the heat storage bulge (3 m) and the heat insulation function of the oxide film (1b) The exhaust heat released from the exhaust manifold (3) to the outside of the exhaust manifold (3) is suppressed, and the exhaust heat that can be used by the supercharger (4) increases, so that the supercharging efficiency is high.

As shown in FIG. 5, this engine is provided with an exhaust aftertreatment device (23) on the exhaust downstream side of the exhaust manifold (3).
Therefore, the following effects can be obtained with this engine.
Heat is stored in the exhaust manifold (3) by the heat storage function of the heat storage bulge (3 m) and the heat insulation function of the oxide film (1b) shown in FIGS. 1 (A) to 1 (E) and FIGS. 2 (A) to 2 (E). Since it is difficult for the exhaust heat to be dissipated to the outside of the exhaust manifold (3), the temperature of the exhaust gas in the exhaust aftertreatment device (23) shown in FIG. 5 can be maintained high, and the exhaust treatment efficiency is high.
Further, due to the heat storage function of the heat storage bulging portion (3 m) shown in FIGS. 1 (A) to (E) and FIGS. 2 (A) to 2 (E) and the heat insulating function of the oxide film (1b) of triiron tetroxide. Exhaust heat stored at high load is radiated to the exhaust when the exhaust temperature is low and / or light load, and the temperature of the exhaust in the exhaust aftertreatment device (23) shown in FIG. 5 rises. / Or exhaust treatment is possible even when the load is light.

In this engine, as shown in FIG. 5, the exhaust aftertreatment device (23) includes a DOC (24).
Therefore, the exhaust heat stored at the time of high load is dissipated to the exhaust at the time of no load and / or light load when the exhaust temperature is low, and the temperature of the exhaust in the exhaust aftertreatment device (23) rises, so that the DOC (24) Is easy to activate.

In this engine, as shown in FIG. 5, the exhaust aftertreatment device (23) includes a DPF (25).
Therefore, in this engine, the exhaust heat stored at the time of high load is radiated to the exhaust at the time of no load and / or light load when the exhaust temperature is low, and the temperature of the exhaust in the exhaust aftertreatment device (23) rises. DPF (25) is easily regenerated.

In this engine, an SCR catalyst (not shown) may be arranged on the exhaust downstream side of the DPF (25) as the exhaust aftertreatment device (23).
In this case, the exhaust heat stored at the time of high load is radiated to the exhaust at the time of no load and / or light load when the exhaust temperature is low, and the temperature of the exhaust in the exhaust aftertreatment device (23) rises, so that the SCR catalyst is activated. Easy to change.

DOC is an abbreviation for diesel oxidation catalyst, and oxidizes CO (carbon monoxide) and NO (nitric oxide) in engine exhaust. The DOC uses a flow-through type ceramic honeycomb in which a large number of cells along the axial length are arranged side by side in a penetrating manner, and oxidation catalyst components such as platinum, palladium, and rhodium are supported in the cells. There is. The DOC (24) is housed in the exhaust aftertreatment case (23a) on the exhaust upstream side of the DPF (25).
DPF is an abbreviation for diesel particulate filter, which captures PM in engine exhaust. PM is an abbreviation for particulate matter. In the DPF, a wall flow type ceramic honeycomb in which a large number of cells along the axial length direction are arranged side by side and the inlets and outlets of adjacent cells are alternately sealed is used.
The SCR catalyst is an abbreviation for a selective catalytic reduction type catalyst, and a flow-through honeycomb type catalyst in which a large number of cells along the axial length direction are arranged side by side in a penetrating manner is used.

In this engine, as shown in FIG. 1 (A), the heat storage bulge (3 m) is used as a mounting portion for the accessory part (26) of the exhaust manifold (3).
Therefore, in this engine, the heat storage bulging portion (3 m) can be effectively used as a mounting portion for the accessory part (26).

In this engine, as shown in FIG. 1A, the accessory part (26) of the exhaust manifold (3) is the heat shield cover (26a) of the exhaust manifold (3).
Therefore, in this engine, the heat shield cover (26a) suppresses the release of exhaust heat from the exhaust manifold (3) to the outside of the exhaust manifold (3).

In this engine, as shown in FIG. 1 (C), the exhaust manifold (3) guides the fastening tool (27) of the fastener (2) for fastening the exhaust manifold (3) to the cylinder head (6). The tool guide groove (28) is provided, and as shown in FIGS. 1B and 1C, the heat storage bulging portion (3 m) is arranged at a position adjacent to the tool guide groove (28).
Therefore, in this engine, the rigidity of the exhaust manifold (3), which is lowered by the recess of the tool guide groove (28), can be strengthened by the heat storage bulge (3 m).
The fastening tool (27) includes a box wrench and the like.

In this engine, the film thickness of the oxide film (1b) of triiron tetroxide is 0.2 μm to 11 μm.
Therefore, the following effects can be obtained with this engine.
That is, if the thickness of the oxide film (1b) is less than 0.2 μm, the heat insulating function and the rust preventive function against red rust are insufficient, and if it exceeds 11 μm, the treatment time for forming the oxide film (1b) is long. Alternatively, while the treatment temperature is high, at 0.2 μm to 11 μm, the heat insulating function and the rust preventive action of the oxide film (1b) against red rust are sufficient, and the treatment time is short or the treatment temperature is low.

The film thickness of the oxide film (1b) of triiron tetroxide may exceed 11 μm and may be 20 μm or less.
The reason is as follows.
When the operating conditions of the engine are harsh and the rate of thermal deterioration of the oxide film (1b) due to combustion heat is high, such as an industrial engine in which high-load operation continues for a long time, the film thickness is 11 μm or less. Then, the service life of the oxide film (1b) may be insufficient. On the other hand, if the film thickness exceeds 20 μm, the treatment time of the oxide film (1b) may exceed the permissible range for manufacturing efficiency, or the treatment temperature may exceed the permissible range for protection of manufacturing equipment.
On the other hand, when the film thickness of the oxide film (1b) of triiron tetroxide exceeds 11 μm and is 20 μm or less, a sufficient service life can be obtained even under severe engine operating conditions, and the treatment can be performed. The time tends to fall within the permissible range for manufacturing efficiency, and the processing temperature also tends to fall within the permissible range for manufacturing equipment protection.
For the same reason as described above, the lower limit of the film thickness may be 10 μm, and the film thickness range may be 10 μm to 20 μm.

As shown in FIG. 4 (A), this engine includes an exhaust passage component (1) and a fastener (2) for fastening the exhaust passage component (1) to other parts, and is provided with a fastener (2). As shown in (F), the exhaust passage component (1) includes a pressure receiving surface (1a) that receives the tightening force of the fastener (2).

As shown in FIGS. 4B to 4F, this engine includes an oxide film (1b) of triiron tetroxide formed on the pressure receiving surface (1a) of the exhaust passage component (1).
Therefore, the following effects can be obtained with this engine.
Compared with the case where a rust preventive resin film is formed on the pressure receiving surface of the exhaust passage component, the oxide film (1b) of triiron tetroxide is less likely to be plastically deformed, and the tightening force of the fastener (2) is less likely to decrease.
Further, the rust preventive action of the oxide film (1b) of triiron tetroxide prevents the generation of red rust due to the exhaust heat on the pressure receiving surface (1a) of the exhaust passage component (1).

As shown in FIGS. 2 (A) to (E), 3 (A) to (E), and 4 (A) to (F), this engine includes exhaust passage components other than the pressure receiving surface (1a). It is provided with an oxide film (1b) of triiron tetroxide formed on the outer surface (1c) of 1).
Therefore, the following effects can be obtained with this engine.
Compared with the case where a rust preventive resin film is formed on the outer surface of the exhaust passage component other than the pressure receiving surface, the oxide film (1b) of triiron tetroxide has excellent heat resistance, and the outer surface (1) of the exhaust passage component (1) Cracks and discoloration in 1c) are unlikely to occur.
Further, the oxide film (1b) of triiron tetroxide prevents the generation of red rust due to the exhaust heat on the outer surface (1c) of the exhaust passage component (1) other than the pressure receiving surface (1a).

In this engine, as shown in FIGS. 1 (A) (B) (C), 2 (A) (E), and 3 (C) (D), the inner surface (1d) of the exhaust passage component (1) ) Does not have an oxide film of triiron tetroxide.
In this engine, an oxide film of triiron tetroxide may be formed on the inner surface of the exhaust passage component (1). In this case, the oxide film of triiron tetroxide (1b) is used to form the exhaust passage. The generation of red rust due to exhaust heat on the inner surface (1d) of the component (1) is prevented.

In this engine, as shown in FIGS. 4B, 4C, and 4E, oxidation of triiron tetroxide formed on the pressure receiving surface (1a) of the exhaust manifold (3), which is an exhaust passage component (1). It has a film (1b).
Therefore, the following effects can be obtained with this engine.
Since the tightening force of the fastener (2) received by the pressure receiving surface (1a) of the exhaust manifold (3) shown in FIGS. 4 (B), (C) and (E) is unlikely to decrease, the fastener (2) is used for fastening. The close contact between the exhaust manifold (3) to be manufactured and other parts (the exhaust turbine housing (4a) and the exhaust relay pipe (5) of the cylinder head (6) and the supercharger (4)) is maintained high.

As shown in FIG. 4B, the pressure receiving surface (1a) of the exhaust manifold (3) is formed on the front and back surfaces of the exhaust inlet flange (3a). The exhaust inlet flange (3a) is fastened to the side wall (6a) of the cylinder head (6) with a fastener (2).
This fastener (2) is a headed bolt (2a), includes a bolt head (2b) and a male screw portion (2c), and the male screw portion (2c) provides a bolt insertion hole (3b) for an exhaust inlet flange (3a). It penetrates and is screw-fitted into the female screw hole (6b) of the side wall (6a) of the cylinder head (6), and a washer (2d) or a first gasket (6d) is inserted between the bolt head (2b) and the cylinder head (6). The exhaust inlet flange (3a) is sandwiched together with the exhaust inlet flange (3c), and the tightening force of the head bolt (2a) is applied to the pressure receiving surface (1a) formed on the front and back surfaces of the exhaust inlet flange (3a).
An oxide film (1b) of triiron tetroxide is formed on the pressure receiving surface (1a).

As shown in FIG. 4C, the pressure receiving surface (1a) of the exhaust manifold (3) is also formed on the upper surface of the exhaust outlet flange (3d). The exhaust inlet flange (4b) of the exhaust turbine housing (4a) of the turbocharger (4) is fastened to the exhaust outlet flange (3d) with the fastener (2).
This fastener (2) is an implantable bolt nut (2e), includes an implantable bolt (2f) and a nut (2 g), and the implantable bolt (2f) is an exhaust outlet flange (3d) of the exhaust manifold (3). It is screw-fitted into the female screw hole (3e), and the implant bolt (2f) penetrates the bolt insertion hole (4c) of the exhaust inlet flange (4b) of the exhaust turbine housing (4a) of the booster (4). A nut (2g) is screw-fitted to the implant bolt (2f), and a seat (2d) or a second gasket (4d) is formed between the exhaust outlet flange (3d) and the nut (2g) of the exhaust manifold (3). The exhaust inlet flange (4b) of the exhaust turbine housing (4a) is sandwiched with the bolt and nut (2e) embedded in the pressure receiving surface (1a) formed on the upper surface of the exhaust outlet flange (3d) of the exhaust manifold (3). Tightening force is applied.
An oxide film (1b) of triiron tetroxide is also formed on the pressure receiving surface (1a).

In this engine, as shown in FIGS. 4C and 4D, four formed on the pressure receiving surface (1a) of the exhaust turbine housing (4a) of the supercharger (4) which is the exhaust passage component (1). It has an oxide film (1b) of triiron oxide.
Therefore, the following effects can be obtained with this engine.
Since the tightening force of the fastener (2) received by the pressure receiving surface (1a) of the exhaust turbine housing (4a) shown in FIGS. 4 (C) and 4 (D) is unlikely to decrease, the fastener (2) is used for fastening. The tightness between the exhaust turbine housing (4a) of the turbocharger (4) and other parts (exhaust manifold (3) and exhaust relay pipe (5)) is maintained high.

As shown in FIG. 4C, the pressure receiving surfaces (1a) of the exhaust turbine housing (4a) are formed on the upper, lower, front and back surfaces of the exhaust inlet flange (4b). As described above, the exhaust inlet flange (4b) is fastened to the exhaust outlet flange (3d) of the exhaust manifold (3) with an embedded bolt nut (2e).
Therefore, the tightening force of the implant bolt nut (2e) is applied to the pressure receiving surfaces (1a) formed on the upper and lower front and back surfaces of the exhaust inlet flange (4b) of the exhaust turbine housing (4a).
An oxide film (1b) of triiron tetroxide is formed on the pressure receiving surface (1a).

As shown in FIG. 4D, the pressure receiving surface (1a) of the exhaust turbine housing (4a) is also formed on the rear surface of the exhaust outlet portion (4e). The exhaust inlet flange (5a) of the exhaust relay pipe (5) is fastened to the exhaust outlet portion (4e) of the exhaust turbine housing (4a) with a fastener (2).
This fastener (2) is a bolt with a head (2a), includes a bolt head (2b) and a male screw portion (2c), and the male screw portion (2c) is attached to the exhaust inlet flange (5a) of the exhaust relay pipe (5). It penetrates the bolt insertion hole (5b) and is screw-fitted into the female screw hole (4f) of the exhaust outlet portion (4e) of the exhaust turbine housing (4a) to form the bolt head (2b) and the exhaust turbine housing (4a). The exhaust inlet flange (5a) of the exhaust relay pipe (5) is sandwiched between the exhaust outlet portion (4e) together with the washer (2d) and the third gasket (4 g), and the exhaust outlet portion of the exhaust turbine housing (4a). The tightening force of the headed bolt (2a) is applied to the pressure receiving surface (1a) formed on the rear surface of (4e).
An oxide film (1b) of triiron tetroxide is also formed on the pressure receiving surface (1a).

In this engine, as shown in FIGS. 4 (D) to (F) and 5 (A) to (E), the pressure receiving surface (1a) of the exhaust relay pipe (5), which is an exhaust passage component (1), is used. It has an oxide film (1b) of triiron tetroxide formed.
Therefore, the following effects can be obtained with this engine.
That is, since the tightening force of the fastener (2) received by the pressure receiving surface (1a) of the exhaust relay pipe (5) shown in FIGS. 4 (D) to 4 (F) is unlikely to decrease, the fastener (2) is used. The tightness between the exhaust relay pipe (5) to be fastened and other parts (exhaust turbine housing (4a), exhaust manifold (3), exhaust post-treatment case (23a), exhaust muffler, exhaust duct) is maintained high. To.

As shown in FIG. 4D, the pressure receiving surfaces (1a) of the exhaust relay pipe (5) are formed on the front and rear front and back surfaces of the exhaust inlet flange (5a). As described above, the exhaust inlet flange (5a) of the exhaust relay pipe (5) is fastened to the exhaust outlet portion (4e) of the exhaust turbine housing (4a) with a headed bolt (2a).
Therefore, the tightening force of the head bolt (2a) is applied to the pressure receiving surfaces (1a) formed on the front and rear front and back surfaces of the exhaust inlet flange (5a) of the exhaust relay pipe (5).
An oxide film (1b) of triiron tetroxide is also formed on the pressure receiving surface (1a).

As shown in FIG. 4 (E), the pressure receiving surfaces (1a) of the exhaust relay pipe (5) are also formed on the upper and lower front and back surfaces of the mounting flange (5c).
The mounting flange (5c) of the exhaust relay pipe (5) is fastened to the upper surface of the mounting seat (3f) arranged above the exhaust manifold (3) with the fastener (2).
This fastener (2) is a headed bolt (2a), includes a bolt head (2b) and a male threaded portion (2c), and the male threaded portion (2c) is a bolt of a mounting flange (5c) of an exhaust relay pipe (5). It penetrates the insertion hole (5d) and is screw-fitted into the female screw hole (3g) of the mounting seat (3f) of the exhaust manifold (3), and the bolt head (2b) and the mounting seat (3f) of the exhaust manifold (3) are fitted. The mounting flange (5c) of the exhaust relay pipe (5) is sandwiched between the washer (2d) and the seat (2d), and is formed on the pressure receiving surface (1a) formed on the upper surface of the mounting seat (3f) of the exhaust manifold (3). The tightening force of the headed bolt (2a) is applied.
An oxide film (1b) of triiron tetroxide is also formed on the pressure receiving surface (1a).

As shown in FIG. 4 (F), the pressure receiving surface (1a) of the exhaust relay pipe (5) is also formed on the front and rear front and back surfaces of the exhaust outlet flange (5e). The exhaust outlet flange (5e) has a fastener (not shown) in which the exhaust inlet flange (23b) of the exhaust aftertreatment case (23a) shown in FIG. 5 penetrates the bolt insertion hole (5f) of the exhaust outlet flange (5e). , Bolts and nuts are used).
Therefore, the tightening force of the fastener is applied to the pressure receiving surfaces (1a) formed on the front and rear front and back surfaces of the exhaust outlet flange (5e) of the exhaust relay pipe (5).
An oxide film (1b) of triiron tetroxide is also formed on the pressure receiving surface (1a).

As shown in FIGS. 2A, 2B, and 2E, the exhaust manifold (3) has a collector portion (3h) long in the front-rear direction and a plurality of exhausts arranged on one side of the collector portion (3h). It comprises an inlet flange (3a), a single exhaust outlet flange (3d) located above the collector portion (3h), and a mounting seat (3f) located above the rear portion of the collector portion (3h). An oxide film (1b) of triiron tetroxide is also formed on the outer surface (1c) of the meat wall other than the pressure receiving surface (1a) of each part.
The bolt insertion holes (3b) of the exhaust inlet flange (3a) shown in FIGS. 2B and 2E and the inner side surfaces (1d) of the exhaust outlet (3j) of the exhaust outlet flange (3d) shown in FIG. 2A. ), An oxide film (1b) of triiron tetroxide is formed.
An oxide film of triiron tetroxide is not formed in the exhaust passage inside the collector portion (3h), but an oxide film (1b) of triiron tetroxide is formed in the exhaust passage inside the collector portion (3h). It may be formed.

As shown in FIG. 4A, the exhaust turbine housing (4a) of the turbocharger (4) has a housing body (4h) and an exhaust inlet flange (4b) arranged under the housing body (4h). And an exhaust outlet portion (4e) arranged on the rear side of the housing body (4h) is provided, and an oxide film (1b) of triiron tetroxide is also provided on the outer surface (1c) other than the pressure receiving surface (1a) of each portion. ) Is formed.
The exhaust passage of the housing body (4h), the exhaust inlet (not shown) of the exhaust inlet flange (4b), and the exhaust outlet (not shown) of the exhaust outlet portion (4e) have three tetroxide on each inner surface. Although an iron oxide film is not formed, an oxide film of triiron tetroxide may be formed on each of these inner surfaces.

As shown in FIGS. 3A to 3E, the exhaust relay pipe (5) includes a pipe portion (5 g), an exhaust inlet flange (5a) arranged in front of the pipe portion (5 g), and a pipe portion. It is provided with an exhaust outlet flange (5e) arranged on the rear side of (5 g) and a mounting flange (5c) arranged on the lower side of the exhaust outlet flange (5e), and meat other than the pressure receiving surface (1a) of each of these parts. An oxide film (1b) of triiron tetroxide is also formed on the outer surface (1c) of the wall.
The bolt insertion hole (5d) of the mounting flange (5c) shown in FIG. 3 (B), the exhaust inlet (5h) and the bolt insertion hole (5b) of the exhaust inlet flange (5a) shown in FIG. An oxide film (1b) of triiron tetroxide is also formed on the inner side surfaces (1d) of the exhaust outlet (5i) and the bolt insertion hole (5f) of the exhaust outlet flange (5e) shown in 3 (C). ..
An oxide film of triiron tetroxide is not formed in the exhaust passage inside the pipe portion (5 g), but an oxide film (1b) of triiron tetroxide is formed in the exhaust passage inside the pipe portion (5 g). It may be formed.

The thickness of the oxide film (1b) of triiron tetroxide formed on the outer surface (1c) and inner surface (1d) of the peripheral wall of the exhaust passage component (1) may be 0.2 μm to 11 μm. Although it is desirable, the thickness of the oxide film (1b) of triiron tetroxide formed on the pressure receiving surface (1a) of the exhaust passage component (1) is preferably 5 μm to 11 μm.
When the film thickness is 5 μm to 11 μm, the following effects can be obtained.
If the thickness of the oxide film (1b) is less than 5 μm, the service life of the rust preventive function of the oxide film (1b) against red rust becomes short, and if it exceeds 11 μm, the treatment time for forming the oxide film (1b) becomes long. While the time or treatment temperature becomes high, when 5 μm to 11 μm, the service life of the rust preventive function of the oxide film (1b) against red rust is long, and the treatment time is short or the treatment temperature is low.
In order to form an oxide film (1b) of triiron tetroxide on the surface of the iron-based metal exhaust passage component (1), the iron-based metal exhaust passage component (1) is treated with a steam film in a steam atmosphere. To do.

The film thickness of the oxide film (1b) of triiron tetroxide may exceed 11 μm and may be 20 μm or less.
The reason is as follows.
When the operating conditions of the engine are harsh and the thermal deterioration rate of the oxide film (1b) due to combustion heat is high, such as an industrial engine in which high-load operation continues for a long time, or the oxide film (1b) due to vibration ), If the film thickness is 11 μm or less, the service life of the oxide film (1b) may be insufficient. On the other hand, if the film thickness exceeds 20 μm, the treatment time of the oxide film (1b) may exceed the permissible range for manufacturing efficiency, or the treatment temperature may exceed the permissible range for protection of manufacturing equipment.
On the other hand, when the film thickness of the oxide film (1b) of triiron tetroxide exceeds 11 μm and is 20 μm or less, a sufficient service life can be obtained even under severe engine operating conditions, and the treatment can be performed. The time tends to fall within the permissible range for manufacturing efficiency, and the processing temperature also tends to fall within the permissible range for manufacturing equipment protection.
For the same reason as described above, the lower limit of the film thickness may be 10 μm, and the film thickness range may be 10 μm to 20 μm.

In this engine, the oxide film (1b) of triiron tetroxide is formed on the surface of the exhaust passage component (1) that has not been surface-treated, but the exhaust passage component (1) that has been surface-treated. ) May be formed on the surface.
For example, an oxide film (1b) of triiron tetroxide may be formed on the surface of the nitrogen compound layer of the exhaust passage component (1) obtained by the surface treatment of nitriding.
In this case, the following effects can be obtained.
When a nitrogen compound layer is formed on the pressure receiving surface (1a), the hardness of the pressure receiving surface (1a) can be increased by the nitrogen compound layer, and softening due to denitrification of the nitrogen compound layer is suppressed by the oxide film (1b). Therefore, the tightening force of the fastener (2) is unlikely to decrease.

In the above embodiment, cast iron is used as the iron-based metal used as the material of the exhaust passage component (1), but steel may be used.
Steel is used as the material for the fastener (2), the washer (2d), and each gasket (3c) (4d) (4g).

(1) ... Exhaust passage component, (1a) ... Pressure receiving surface, (1b) ... Oxide film, (1c) ... Outer surface, (3) ... Exhaust manifold, (4) ... Supercharger, (4a) ... Exhaust Turbine housing, (5) ... Exhaust relay pipe, (6) ... Cylinder head, (6c) ... Exhaust port, (23) ... Exhaust aftertreatment device, (24) ... DOC, (25) ... DPF, (26) ... Accessories, (26a) ... Heat shield cover, (27) ... Fastening tool, (28) ... Tool guide groove.

Claims (16)

An exhaust manifold (3) is provided as an exhaust passage component (1) constituting the exhaust passage, and the exhaust manifold (3) is a bulging portion (3 m) for heat storage of an iron-based metal that bulges outward from a wall (3k). ), And an oxide film (1b) of triiron tetroxide formed on the bulging surface (3n) of the bulging portion (3m) for heat storage. In the engine according to claim 1,
The heat storage bulging portion (3 m) is an engine characterized in that the bulging portion (3 m) bulges outward from a meat wall portion (3 ka) to which the exhaust gas flowing out from the exhaust port (6c) of the cylinder head (6) is blown. In the engine according to claim 1 or 2.
The exhaust manifold (3) is an oxide film of triiron tetroxide (1c) formed on the outer surface (1c) of the wall (3k) of an iron-based metal other than the bulging surface (3n) of the bulging portion (3m) for heat storage. An engine characterized by having 1b). In the engine according to any one of claims 1 to 3.
The exhaust turbine housing (4a) of the turbocharger (4) is provided as the exhaust passage component (1).
The exhaust turbine housing (4a) is an engine including an oxide film (1b) of triiron tetroxide formed on the outer surface (1c) of a wall of an iron-based metal. In the engine according to any one of claims 1 to 4.
An exhaust relay pipe (5) is provided as an exhaust passage component (1).
The exhaust relay pipe (5) is an engine characterized by having an oxide film (1b) of triiron tetroxide formed on the outer surface (1c) of a wall of an iron-based metal. In the engine according to any one of claims 1 to 5.
An engine characterized in that the iron-based metal is cast iron. In the engine according to any one of claims 1 to 6.
An engine characterized in that a supercharger (4) is provided on the downstream side of the exhaust of the exhaust manifold (3). In the engine according to any one of claims 1 to 7.
The exhaust aftertreatment device (23) is provided on the exhaust downstream side of the exhaust manifold (3). In the engine according to claim 8,
The exhaust gas aftertreatment device (23) is an engine including a DOC (24). In the engine according to claim 8 or 9.
The exhaust aftertreatment device (23) is provided with a DPF (25). In the engine according to any one of claims 8 to 10.
The exhaust gas aftertreatment device (23) is an engine including an SCR catalyst. In the engine according to any one of claims 1 to 11.
An engine characterized in that a bulge for heat storage (3 m) is used as a mounting part for an accessory (26) of an exhaust manifold (3). In the engine according to claim 12,
An engine characterized in that the accessory part (26) of the exhaust manifold (3) is the heat shield cover (26a) of the exhaust manifold (3). In the engine according to any one of claims 1 to 13.
The exhaust manifold (3) is provided with a tool guide groove (28) for guiding a tool (27) for fastening the fastener (2) for fastening the exhaust manifold (3) to the cylinder head (6).
The engine is characterized in that the heat storage bulge (3 m) is arranged at a position adjacent to the tool guide groove (28). In the engine according to any one of claims 1 to 14.
An engine characterized in that the film thickness of the oxide film (1b) of triiron tetroxide is 0.2 μm to 11 μm. In the engine exhaust device according to any one of claims 1 to 14.
An engine exhaust device characterized in that the film thickness of the oxide film (1b) of triiron tetroxide exceeds 11 μm and is 20 μm or less.

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