ATMOSPHERE RELEASE DEVICE FOR A BLOWBY GAS

Abstract

Blow-by gas atmosphere release device (20) for an engine (1) in which an inlet flow path (3) for intake air of the engine (1) is arranged on one side of an engine body (2) and an exhaust flow path (4) for exhaust gas of the engine (1) is arranged on the other side, wherein the blow-by gas atmosphere release device (20) comprises: an oil separator (22) which is connected to the engine body (2) and separates oil contained in the blow-by gas; an atmosphere release pipe (23) which is connected to the oil separator (22) and releases the blow-by gas to the atmosphere, wherein the atmosphere release tube (23) extends along the other side of the engine body (2), wherein the atmosphere release tube (23) comprises a heat absorption tube section (27) that absorbs heat from a heat source and a heat insulation tube section (28) with a lower thermal conductivity than the heat absorption tube section (27), wherein the exhaust gas flow path (4) includes short pipe sections (12a) and wherein the heat absorption pipe section (27) is inserted vertically through a gap (G) between the short pipe sections (12a).

Description

TECHNICAL FIELD

[0001] The present invention relates to a blowby gas atmosphere release device that releases blowby gas into the atmosphere. BACKGROUND OF THE TECHNOLOGY

[0002] Blow-by gas is produced when gas in a combustion chamber leaks into a crankcase and cylinder head.

[0003] Therefore, an engine is equipped with a mechanism to release the blow-by gas from the crankcase and cylinder head.

[0004] A positive crankcase ventilation (PCV) system that returns the blow-by gas to an intake side, and a blow-by gas atmosphere release device that releases blow-by gas to the atmosphere, are generally known as such a mechanism. QUOTE LIST PATENT LITERATURE Patent Literature 1: JP H04-246 217 A Patent literature 2: JP 2011-127 490 A Patent literature 3: JP 2016-183 604 A Patent literature 4: JP 2006-220 057 A Patent Literature 5: JP 2006-336 629 A Patent literature 6: DE 10 2010 063 261 A1 Patent literature 7: US 6,772,744 B2 Patent literature 8: DE 10 2010 053 696 B4 Patent literature 9: US 2015 / 0 240 732 A1 Patent literature 10: JP H08-151 917 A

[0005] Patent literature 5 describes the heat absorption of an exhaust pipe for blow-by gas. In this process, a portion of the heated air is directed into a chamber leading to the exhaust pipe.

[0006] Patent literature 6 describes that a heat sensor is formed on a return pipe segment of the blow-by gas return pipe on the side of the blow-by gas inlet.

[0007] Patent literature 7 describes a metal central section of a pipe that forms part of the blow-by gas return path. The central section is in contact with the cylinder head of the engine via a metal clamp. SUMMARY OF THE INVENTION TECHNICAL PROBLEM

[0008] The blow-by gas atmosphere release device has several advantages that the PCV system does not.

[0009] For example, because the blow-by gas atmosphere release device does not return oil-containing blow-by gas to the intake side, a compressor, in particular, can be prevented from being contaminated by oil or the like in a turbocharged vehicle. Furthermore, because the blow-by gas atmosphere release device does not return moisture-containing blow-by gas to the intake side, it can prevent the compressor from being struck by frozen moisture cooled by intake air.

[0010] The blow-by gas atmosphere release device works by allowing frost to form on the inner surface of an atmosphere release tube in a low-temperature environment. This frost can gradually grow and freeze, eventually clogging the tube. Generally, freezing tends to occur around an inner circumferential side of the atmosphere release tube outlet and gradually spreads upstream.

[0011] The present invention is made in light of the above circumstances. One object of the present invention is to provide a blow-by gas atmosphere release device that can prevent the freezing of an atmosphere release tube for releasing blow-by gas to the atmosphere. SOLUTION TO THE PROBLEM

[0012] This problem is solved according to the invention by a blow-by gas atmosphere release device having the features of claim 1.

[0013] According to one aspect of the present invention, a blow-by gas atmosphere release device is provided for an engine, wherein an inlet flow path is arranged on one side of an engine body and an exhaust flow path is arranged on the other side. The blow-by gas atmosphere release device comprises an oil separator connected to the engine body, which separates oil contained in the blow-by gas, and an atmosphere release pipe connected to the oil separator, which is used to release the blow-by gas to the atmosphere. The atmosphere release pipe is arranged along the other side of the engine body.

[0014] The atmosphere release tube comprises a heat absorption tube section that absorbs heat from a heat source and a heat insulation tube section with a lower thermal conductivity than the heat absorption tube section.

[0015] Preferably, the oil separator is arranged on one side of the engine body and the atmosphere release pipe from the oil separator to the other side of the engine body is implemented through the heat insulation pipe section.

[0016] The heat-absorbing pipe section is preferably made of a metal.

[0017] The heat insulation pipe section is preferably made of an elastic resin.

[0018] A layer of thermal insulation material is preferably provided on the outer circumference of the thermal insulation pipe section. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0019] According to the above aspect, freezing of the atmosphere release tube can be prevented, thus preventing the release of blow-by gas to the atmosphere. BRIEF DESCRIPTION OF DRAWINGS Fig. Figure 1 is a front view showing a blow-by gas atmosphere release device according to an embodiment of the present invention. Fig. Figure 2 is a schematic top view showing an engine as seen from above. Fig. Figure 3 is a cross-sectional view showing a section of heat insulation pipe. Fig. Figure 4 is a schematic view showing a condition in which an atmosphere release tube is cooled by outside air. DESCRIPTION OF EXECUTION FORMS

[0020] An embodiment of the present invention is described below with reference to the accompanying drawings. Front, rear, left, right, top, and bottom directions in the embodiment described below refer to directions of a vehicle.

[0021] Fig. Figure 1 is a front view showing a blow-by gas atmosphere release device 20 according to the present invention, as viewed from the front. An engine (internal combustion engine) 1 is a multi-cylinder internal combustion engine of a compression ignition type, mounted on the vehicle, i.e., a diesel engine. The cylinders of the engine can be freely arranged, and the number of cylinders can be set to any desired number.

[0022] The engine 1 comprises an engine body 2, an intake flow path 3 connected to the engine body 2, an exhaust flow path 4 connected to the engine body 2, and a fuel injection device 5. The engine body 2 includes structural components, such as a cylinder head 2a, a cylinder block 2b, and a crankcase 2c, and movable components, such as a piston 6, a crankshaft 7, an intake valve 8a, and an exhaust valve 8b, which are housed within the structural components. A chamber C1 in the cylinder head 2a and a chamber C2 in the crankcase 2c are connected by a gas flow path 2d formed in the cylinder block 2b.

[0023] The intake flow path 3 is located on one side (left side of the vehicle) of the engine block 2. The intake flow path 3 is defined by an intake manifold 9, which is connected to the engine block 2 (in particular the cylinder head 2a), and an intake pipe 10, which is connected to an upstream end of the intake manifold 9. The intake manifold 9 distributes and supplies precisely directed intake air from the intake pipe 10 to the intake ports of the cylinder. The intake pipe 10 is equipped with an air cleaner 11.

[0024] The exhaust flow path 4 is located on the opposite side (right side of the vehicle) of the engine body 2. The exhaust flow path 4 is mainly defined by an exhaust manifold 12, which is connected to the engine body 2 (in particular the cylinder head 2a) and an exhaust pipe 13 located downstream of the exhaust manifold 12.

[0025] As in Fig. As shown in Figure 2, the exhaust manifold 12 comprises several short pipe sections 12a connected to exhaust ports of the cylinder, and a collecting pipe section 12b connected to the short pipe sections 12a, collecting exhaust gas from them. A gap G is formed between the short pipe sections 12a. As shown in Fig. 1 and Fig. As shown in Figure 2, a turbine 14T of a turbocharger 14 is arranged between the exhaust manifold 12 and the exhaust pipe 13. The exhaust pipe 13 downstream of the turbine 14T is equipped with an exhaust gas purification device (not shown) comprising an oxidation catalyst, a particulate filter, and a NOₓ regulator. x -catalyst, an ammonia oxidation catalyst and the like.

[0026] The motor 1 includes the blow-by gas atmosphere release device 20, which releases the blow-by gas to the atmosphere.

[0027] The blow-by gas atmosphere release device 20 comprises an oil separator 22, which is connected to the space C1 in the cylinder head 2a via a connecting pipe 21 and an atmosphere release pipe 23, which is connected to the oil separator 22 and is used to release the blow-by gas to the atmosphere.

[0028] The oil separator 22 is a device that separates oil contained in the blow-by gas. The oil separator 22 includes a filter (not shown). As the blow-by gas passes through the filter, the oil separator 22 separates the oil contained in the blow-by gas. An oil return pipe 24 for returning the oil separated from the blow-by gas to the engine body 2 is connected to the oil separator 22. The oil return pipe 24 is connected to chamber C2 in the crankcase 2c.

[0029] The oil separator 22 is located on one side (inlet side) of the engine body 2. Oil adheres to the oil separator 22. If the oil separator 22 were located on the other side (exhaust side) of the engine body 2, it could catch fire due to the radiant heat absorbed from the engine body 2. Therefore, the oil separator 22 is generally located on the inlet side of the engine body 2. Specifically, the oil separator 22 is fixed in close proximity to an upper section of the engine body 2 by means of a bracket or the like (not shown). The connecting pipe 21 is designed to be short enough to disregard thermal radiation. Accordingly, the blow-by gas arriving at the oil separator 22 from the engine body 2 through the connecting pipe 21 is prevented from being cooled before reaching the oil separator 22.

[0030] The oil separator 22 is not limited to one that includes a filter. The oil separator 22 may include a labyrinth-type blow-by gas flow path (not shown) or a blow-by gas flow path of another type. The oil separator 22 may be connected to space C1 in the crankcase 2c via the connecting pipe 21 or to the gas flow path 2d of the cylinder block 2b.

[0031] The atmosphere release tube 23 is arranged along an upper surface 25 of the engine body 2 and a side surface 26 on the other side (exhaust side) of the engine body 2.

[0032] Furthermore, the atmosphere release tube 23 comprises a heat absorption tube section 27, which absorbs heat from a heat source, such as the engine body 2 or the exhaust gas flow path 4, and a heat insulation tube section 28 with a lower thermal conductivity than the heat absorption tube section 27. The heat absorption tube section 27 is made of a metal tube, such as steel, copper, or aluminum. The heat insulation tube section 28 is made of an elastic resin.

[0033] The heat-absorbing pipe section 27 is arranged particularly in the immediate vicinity of the heat source. In the present embodiment, the main heat sources include the exhaust manifold 12, the exhaust pipe 13, and the engine body 2, which is located close to the exhaust manifold 12. As shown in Fig. As shown in Figure 2, the heat absorption pipe section 27 is arranged along the side surface 26 on the opposite side (exhaust side) of the engine body 2 and is inserted vertically through the gap G between the short pipe sections 12a. Accordingly, the heat absorption pipe section 27 actively absorbs heat from the heat source.

[0034] The heat-absorbing pipe section 27 is not only applied to a section near a heat source, but also to a high-temperature section. Here, the high-temperature section refers to a section of the atmosphere release pipe 23 where the temperature of the atmosphere release pipe 23 exceeds the thermal resistance temperature of the heat-insulating pipe section 28. As in Fig. As shown in Figure 4, when the vehicle is in motion, the atmosphere release tube 23 radiates heat while absorbing heat from a heat source. The amount of thermal radiation varies depending on the flow rate of the airflow absorbed by the atmosphere release tube 23, the temperature, and other factors, and is therefore not constant. Similarly, the amount of radiant heat from a heat source also varies depending on the engine's operating state (particularly the amount of fuel injected) and other factors, and is not constant. Therefore, the presence of a high-temperature section is verified beforehand by conducting experiments, simulations, and similar procedures.

[0035] For example, in the present embodiment, the high-temperature section is a section of the atmosphere release pipe 23 located on the right side (exhaust side) of the center in a left-right direction of the engine body 2 and above a center height of the crankshaft 7. Such a high-temperature section comprises the heat-absorbing pipe section 27.

[0036] The heat-insulating pipe section 28 is attached to a different section than the high-temperature section. Specifically, the heat-insulating pipe section 28 is attached to a section of the atmosphere release pipe 23 on the left side (inlet side) of the center in the left-right direction of the engine body 2, and to a section below the center height of the crankshaft 7. The heat-insulating pipe section 28 is made of a material whose thermal conductivity is lower than that of the heat-absorbing pipe section 27 and on which frost is unlikely to freeze. In particular, the heat-insulating pipe section 28 is implemented as a rubber tube. Therefore, even when the heat-insulating pipe section 28 absorbs low-temperature airflow, heat radiation from the heat-insulating pipe section 28 is prevented, and frost within the heat-insulating pipe section 28 is prevented from freezing.

[0037] As in Fig.As shown in Figure 3, a thermal insulation layer 29 is arranged on the outer circumference of the thermal insulation pipe section 28. Specifically, the thermal insulation layer 29 is made of a foamed resin with thermal resistance and flame retardancy. The foamed resin is, for example, made of ethylene propylene rubber (EPDM). The thermal insulation layer 29 is formed by spirally winding a ribbon-shaped foamed resin around the outer circumference of the thermal insulation pipe section 28.

[0038] The thermal insulation material layer 29 is not limited to this. For example, the thermal insulation material layer 29 can be formed by spraying and coating a foam-like resin onto the outer circumference of the thermal insulation pipe section 28. A thermal insulation material is not limited to EPDM. The thermal insulation material can be another type of material with excellent thermal insulation, thermal resistance, and flame retardancy.

[0039] Next, the effects of the present embodiment will be described.

[0040] When the engine 1 is operated, air-fuel mixture or afterburner gas in the combustion chamber leaks into chamber C2 of the crankcase 2c or chamber C1 of the cylinder head 2a from a gap or similar between the piston 6 and the cylinder block 2b, generating blow-by gas. At this point, the atmospheric release pipe 23 releases the blow-by gas to the atmosphere, and the connecting pipe 21 communicates with the atmospheric release pipe 23 via the oil separator 22. Therefore, the blow-by gas in chambers C1 and C2 of the crankcase 2c and the cylinder head 2a flows through the connecting pipe 21, the oil separator 22, and the atmospheric release pipe 23 in that order, and the blow-by gas is released to the atmosphere by the atmospheric release pipe 23. At this point, the blow-by gas passes through the filter in the oil separator 22. As a result, the oil contained in the blow-by gas is collected by the filter and separated from the blow-by gas.The oil separated from the blow-by gas is returned to the crankcase 2c via the oil return pipe 24.

[0041] When engine 1 is operating, high-temperature exhaust gas flows through the exhaust manifold 12, the turbine 14T, and the exhaust pipe 13 in that order and is discharged through the exhaust aftertreatment device. As a result, the temperatures of the engine body 2, the exhaust manifold 12, the turbine 14T, and the exhaust pipe 13 are increased, generating radiant heat. Some of this radiant heat warms the atmospheric discharge pipe 23. Consequently, the blow-by gas in the atmospheric discharge pipe 23 is heated. In particular, the heat-absorbing pipe section 27 is made of a metal with high thermal conductivity. Therefore, the temperature of the blow-by gas flowing through the heat-absorbing pipe section 27 is efficiently increased.

[0042] The thermal insulation pipe section 28 of the atmosphere release pipe 23 is made of a resin with low thermal conductivity. Therefore, thermal radiation from the thermal insulation pipe section 28 is prevented, and the temperature of the blow-by gas in the thermal insulation pipe section 28 is prevented from decreasing.

[0043] For example, when the vehicle is operating in a low-temperature environment, the low-temperature airflow encounters the atmospheric discharge pipe 23. The atmospheric discharge pipe 23, running from the oil separator 22 to the other side (exhaust side) of the engine 1, does not absorb significant radiant heat. Therefore, the blow-by gas tends to be cooled as it flows from the oil separator 22 to the other side of the engine 1. However, the atmospheric discharge pipe 23, running from the oil separator 22 to the other side of the engine 1, incorporates the heat-insulating pipe section 28. This prevents the temperature of the blow-by gas from decreasing and inhibits frost formation within the heat-insulating pipe section 28. The blow-by gas arriving at the other side of the engine body 2 is warmed by radiant heat from the heat source.At this point, the atmosphere release pipe 23, located above and on the opposite side of the engine body 2, is implemented through the heat-absorbing pipe section 27. Therefore, radiant heat is efficiently transferred from an outer circumferential surface to an inner circumferential surface of the heat-absorbing pipe section 27, and the temperature of the blow-by gas is efficiently increased. Subsequently, as the blow-by gas flows through the heat-absorbing pipe section 27 near the exhaust manifold 12, its temperature is further increased, and the blow-by gas then flows to the heat-insulating pipe section 28 below the exhaust manifold 12. The heat-insulating pipe section 28 does not absorb radiant heat. Therefore, the blow-by gas tends to be cooled again. However, the thermal conductivity of the heat-insulating pipe section 28 is low, and the temperature of the blow-by gas is pre-heated by the heat-absorbing pipe section 27.Therefore, the blow-by gas is kept at a relatively high temperature up to an outlet of the atmosphere release tube 23, and freezing inside the atmosphere release tube 23 is prevented.

[0044] As described above, the atmosphere release pipe 23 is arranged along the exhaust side of the engine body 2. Therefore, the temperature of the blow-by gas in the atmosphere release pipe 23 can be increased by radiant heat from the engine body 2, thus preventing freezing inside the atmosphere release pipe 23.

[0045] The atmosphere release pipe 23 comprises the heat-absorbing pipe section 27, which absorbs heat from the heat source, and the heat-insulating pipe section 28, which has a lower thermal conductivity than the heat-absorbing pipe section 27. The atmosphere release pipe 23 is located close to the exhaust gas flow path 4 and is formed by the heat-absorbing pipe section 27. Therefore, the temperature of the blow-by gas in the heat-absorbing pipe section 27 can be increased by radiant heat from the exhaust gas flow path 4 and the engine body 2 located close to the exhaust gas flow path 4. This prevents freezing within the atmosphere release pipe 23 downstream of the heat-absorbing pipe section 27.

[0046] The atmospheric release pipe 23 from the oil separator 22 to the other side of the engine body 2 is implemented through the heat-insulating pipe section 28. Therefore, heat radiation from the atmospheric release pipe 23, which is located from the oil separator 22 to the other side of the engine body 2, can be prevented.

[0047] Since the heat absorption pipe section 27 is made of a metal pipe, the radiant heat from the heat source can be efficiently transferred to the blow-by gas and the heat absorption pipe section 27 can be formed at low cost.

[0048] Since the heat insulation pipe section 28 is made of an elastic resin tube, it is possible to prevent the temperature of the blow-by gas from being reduced and the heat insulation pipe section 28 can be formed easily and at low cost.

[0049] Since the heat insulation material layer 29 is arranged on the outer circumference of the heat insulation tube section 28, heat radiation from the heat insulation tube section 28 can be further prevented.

[0050] Although the embodiment of the present invention has been described in detail above, the present invention may also have other embodiments as follows.

[0051] For example, in the present embodiment, the heat absorption pipe section 27 is arranged between the short pipe sections 12a of the outlet manifold 12. Alternatively, the heat absorption pipe section 27 can be arranged between the outlet manifold 12 and the turbine 14T.

[0052] Configurations of the embodiments described above can be partially or completely combined, provided there is no contradiction. The embodiments of the present invention are not limited to those described above, and all modifications, applications, and equivalents that fall within the scope of the present invention, as defined by the claims, are included in the present invention. Accordingly, the present invention should not be interpreted as limiting and can be applied to any other technology that falls within the scope of the present invention.

[0053] The present application is based on the Japanese patent application (No. 2018-149264), filed on August 8, 2018, the contents of which are incorporated herein by reference. INDUSTRIAL APPLICABILITY

[0054] According to the present invention, freezing of the atmosphere release pipe for the release of blow-by gas to the atmosphere is prevented. Thermal radiation from the atmosphere release pipe, which is located from the oil separator to the other side of the engine body, is prevented. Since the heat-absorbing pipe section is made of a metal tube, radiant heat from the heat source is efficiently transferred to the blow-by gas, and the heat-absorbing pipe section is manufactured at low cost. Since the heat-insulating pipe section is made of an elastic resin tube, a reduction in the temperature of the blow-by gas is prevented, and the heat-insulating pipe section is manufactured easily and at low cost. Since the heat-insulating material layer is provided on the outer circumference of the heat-insulating pipe section, thermal radiation from the heat-insulating pipe section is further prevented. LIST OF REFERENCE SYMBOLS 1 engine 2 engine bodies 2a Cylinder head 2b Cylinder block 2c crankcase 2d gas flow path 3 Inlet flow path 4 Exhaust gas flow path 5 Fuel injection device 6 pistons 7 Crankshaft 8a Inlet valve 8b Exhaust valve 9 Intake manifolds 10 Inlet pipe 11 air purifiers 12 exhaust manifolds 12a short pipe section 12b Collector pipe section 13 Exhaust pipe 14 turbochargers 14T Turbine 20 Blow-by gas atmosphere release device 21 Connecting pipe 22 oil separators 23 Atmosphere release tube 24 Oil return pipe 25 upper surface 26 side surface 27 Heat absorption pipe section 28 Thermal insulation pipe section 29 Thermal insulation material layer C1 Room C2 Room G Gap

Claims

[1] A blowby gas atmosphere release device (20) for an engine (1), wherein an intake flow path (3) for intake air of the engine (1) is arranged on one side of an engine body (2) and an exhaust flow path (4) for exhaust gas of the engine (1) is arranged on the other side, the blowby gas atmosphere release device (20) comprising: an oil separator (22) connected to the engine body (2) and separating oil contained in the blow-by gas; an atmosphere release pipe (23) connected to the oil separator (22) and releasing the blow-by gas to the atmosphere, wherein the atmosphere release pipe (23) extends along the other side of the engine body (2), wherein the atmosphere release tube (23) comprises a heat absorption tube section (27) which absorbs heat from a heat source, and a heat insulation tube section (28) with a lower thermal conductivity than the heat absorption tube section (27), wherein the exhaust gas flow path (4) comprises short pipe sections (12a) and wherein the heat receiving tube section (27) is inserted vertically through a gap (G) between the short tube sections (12a). [2] Blowby gas atmosphere release device (20) according to claim 1, wherein the oil separator (22) is arranged on one side of the engine body (2), and wherein the atmosphere release pipe (23) is implemented from the oil separator (22) to the other side of the engine body (2) through the heat insulating pipe portion (28). [3] The blowby gas atmosphere release device (20) according to claim 1 or 2, wherein the heat receiving tube portion (27) is made of a metal. [4] The blow-by gas atmosphere release device (20) according to any one of claims 1 to 3, wherein the heat insulating tube portion (28) is made of an elastic resin. [5] The blow-by gas atmosphere release device (20) according to any one of claims 1 to 4, wherein a heat insulating material layer (29) is provided on an outer periphery of the heat insulating tube portion (28).

Images