Engine

Abstract

The present invention provides an engine capable of preventing freezing of moisture in blow-by gas in a blow-by gas recirculation device (12) during a cold start.　An engine according to the present invention includes an engine-related component (P), a heat exchanger (Pa) of the engine-related component (P), an electric water pump (7), and a bypass water passage (B) for circulating engine cooling water (5) between a main water passage (M) and the heat exchanger (Pa) of the engine-related component (P) by the electric water pump (7). The engine includes, as the engine-related component (P), a blow-by gas recirculation device (12) for recirculating blow-by gas in a crank case to an intake path, and is configured such that the blow-by gas recirculation device (12) is heated by the engine cooling water (5) passing through a heat exchanger (12a) of the blow-by gas recirculation device (12).

Description

engine

[0001] The present invention relates to an engine, and more particularly to an engine that can prevent freezing of water in blow-by gas in a blow-by gas recirculation device during cold start.

[0002] Conventionally, there is an engine that includes an engine body, an electric water pump, and a water passage that circulates engine coolant using the electric water pump, and that cools the engine body with the engine coolant (see, for example, Patent Document 1).

[0003] JP 2017-210880 A (see Figures 1 and 2)

[0004] <Problem> It is not possible to prevent freezing of water in the blow-by gas in the blow-by gas recirculation device during cold start. The engine of Patent Document 1 operates an electric water pump in cold weather to prevent icing of the throttle device, but even if the electric water pump is operated, it is not possible to heat the blow-by gas recirculation device with engine coolant, and it is not possible to prevent freezing of water in the blow-by gas in the blow-by gas recirculation device during cold start.

[0005] An object of the present invention is to provide an engine that can prevent freezing of water in blow-by gas in a blow-by gas recirculation device during cold start.

[0006] The main configuration of the present invention is as follows: An engine comprising an engine body, a radiator, a mechanical water pump driven by the crankshaft, a main water passage that cools the engine body by circulating engine coolant between the engine body and the radiator using the mechanical water pump, engine-related parts, a heat exchanger for the engine-related parts, an electric water pump, and a bypass water passage that circulates engine coolant between the main water passage and the heat exchanger for the engine-related parts using the electric water pump, and a blow-by gas recirculation device that recirculates blow-by gas in the crankcase to the intake path as an engine-related part, wherein the blow-by gas recirculation device is configured to be heated by engine coolant that passes through the heat exchanger of the blow-by gas recirculation device.

[0007] The present invention has the following effects. <Effect> Freezing of water in blow-by gas in the blow-by gas recirculation device can be prevented during cold start. With this engine, even during cold start when the engine speed is low and the mechanical water pump is also running at low speed, the electric water pump can be driven at high speed without being affected by the engine speed, and the required amount of engine coolant can be passed through the heat exchanger of the blow-by gas recirculation device to heat the blow-by gas recirculation device, thereby preventing freezing of water in blow-by gas in the blow-by gas recirculation device during cold start.

[0008] FIG. 1 is a block diagram of a cooling water path of an engine according to an embodiment of the present invention. FIG. 2 is a control block diagram of a bypass water passage of the cooling water path of FIG. 1. FIG. 3 is a block diagram illustrating an engine according to an embodiment of the present invention, in which FIG. 3A is a block diagram of an intake path and a blow-by gas recirculation path, and FIG. 3B is a block diagram of an exhaust path and a urea water path. FIG. 4 is a diagram illustrating a specific example 1 of an iron-based foreign matter trapping device (magnetic type) for an engine according to an embodiment of the present invention, in which FIG. 4A is a longitudinal side view, and FIG. 4B is a cross-sectional view taken along line B-B of FIG. 4A. FIG. 5 is a diagram illustrating two specific examples 2 of an iron-based foreign matter trapping device (filter type) for an engine according to an embodiment of the present invention, in which FIG. 5A is a longitudinal side view of specific example 2-1 (flat filter type), FIG. 5B is a cross-sectional view taken along line B-B of FIG. 5A, and FIG. 5C is a longitudinal side view of specific example 2-2 (cylindrical filter type). 6A and 6B are diagrams illustrating an electric water pump and engine-related components used in an engine according to an embodiment of the present invention, with Fig. 6A being a longitudinal side view of the electric water pump, Fig. 6B being a longitudinal side view of an oil separator which is a blow-by gas recirculation device, Fig. 6C being a longitudinal side view of a PCV valve which is also a blow-by gas recirculation device, and Fig. 6D being a longitudinal side view of a urea water injector. Fig. 6B is a front view of an engine according to an embodiment of the present invention, showing the cooling water path of a urea water tank and its heat exchanger, as well as the urea water path. Fig. 6C is a plan view of an engine according to an embodiment of the present invention, showing the cooling water path of an air conditioner and its heat exchanger. Fig. 6D is a left side view of an engine according to an embodiment of the present invention.

[0009] 1 to 9 are diagrams illustrating an engine according to an embodiment of the present invention, and in this embodiment, a water-cooled vertical in-line multi-cylinder diesel engine will be described.

[0010] As shown in Figure 9, the engine body (1) of this engine includes a cylinder block (25), a cylinder head (26) attached to the top of the cylinder block (25), a cylinder head cover (27) attached to the top of the cylinder head (26), an engine cooling fan (28) disposed in front of the cylinder block (25), a flywheel housing (29) attached to the rear of the cylinder block (25), and an oil pan (30) attached to the bottom of the cylinder block (25), with the crankshaft (3) extending in the front-to-rear direction and one side of the front-to-rear direction being the front side. The cylinder block (25) includes a crankcase (9) located near the bottom and a cylinder section (31) located near the top, and the crankshaft (3) is attached within the crankcase (9). As shown in Figure 7, when viewed in a direction parallel to the front-rear direction, the width direction of the engine body 1, which is perpendicular to the front-rear direction and the up-down direction, is the horizontal direction. An intake manifold 32 is assembled to one horizontal side of the cylinder head 26, and an exhaust manifold 33 is assembled to the other horizontal side of the cylinder head 26.

[0011] The engine body 1 includes an intake path 11 shown in Figure 3(A), a blow-by gas recirculation path 34, a fuel supply device (not shown), an exhaust path 36 shown in Figure 3(B), a urea water path 37, and a water cooling device 38 shown in Figure 1. The arrows in Figure 3(A) indicate the piping and flow direction of the intake air 11a or the blow-by gas 10. The intake path 11 is configured as follows. As shown in FIG. 3A, the intake path (11) includes an air cleaner (39), an air compressor (40a) of a supercharger (40), an intake throttle (41), and an intake manifold (32). The intake air (11a) purified by the air cleaner (39) is compressed by the air compressor (40a) and passes through the intake throttle (41) and the intake manifold (32) to be supercharged into the combustion chamber (not shown).

[0012] As shown in Figure 3(A), the blow-by gas recirculation path (34) is a PCV system equipped with the crankcase (9), the cylinder head cover (27), and the blow-by gas recirculation device (12), and the end of the blow-by gas recirculation path (34) is connected to the intake path (11) between the air cleaner (39) and the air compressor (40a), and the blow-by gas (10) generated in the crankcase (9) is recirculated to the intake path (11) via the cylinder head cover (27) and the blow-by gas recirculation device (12). PCV is an abbreviation for positive crankcase ventilation.

[0013] The fuel supply system (not shown) includes a common rail fuel injection system using a common rail (not shown), and fuel stored under pressure in the common rail is supplied to each combustion chamber from a fuel injector (not shown).

[0014] The arrows in Figure 3(B) indicate the piping and flow direction of the exhaust gas (14) or the urea water (15). The exhaust path (36) and the urea water path (37) are configured as follows: As shown in Figure 3(B), the exhaust path (36) includes an exhaust manifold (33), a DOC (44), a DPF (45), an SCR (46), and an ASC (47). The urea water path (37) includes a urea water tank (17), a urea water pump (17d), and a urea water injector (16). The urea water injector (16) adds urea water (15) to the exhaust gas (14) between the DPF (45) and the SCR (46), and injects NOx into the SCR (46). x (nitrogen oxide) is reduced to N2 (nitrogen gas) and H ２ O (water vapor), and the SCR (46) slipped NH ３ The ammonia is purified by the ASC (47). DOC is an abbreviation for diesel oxidation catalyst, DPF is an abbreviation for diesel particulate filter, SCR is an abbreviation for selective catalytic reduction catalyst, and ASC is an abbreviation for oxidation catalyst for purifying ammonia. Note that reference numeral (52) shown in Figure 3(B) and Figures 7 to 9 indicates a DPF housing case that houses the DOC (44) and DPF (45), and reference numeral (53) indicates an SCR housing case that houses the SCR (46) and ASC (47).

[0015] The water-cooling system 38 is configured as follows: As shown in Figure 1, the engine includes an engine body 1, a radiator 2, a mechanical water pump 4 driven by a crankshaft 3, and a main water passage M through which the mechanical water pump 4 circulates engine cooling water 5 between the engine body 1 and the radiator 2 to cool the engine body 1. The engine also includes engine-related parts P, a heat exchanger Pa for the engine-related parts P, an electric water pump 7, and a bypass water passage B through which the electric water pump 7 circulates engine cooling water 5 between the main water passage M and the heat exchanger Pa for the engine-related parts P.

[0016] The arrows in Figure 1 indicate the water passages and flow direction of the engine cooling water 5. The main water passage M is configured as follows: As shown in Figure 1, the main water passage M includes a cylinder jacket 1a surrounding the cylinder (not shown), a head jacket 1b installed inside the cylinder head 26, and a thermostat housing 6 accommodating a thermostat valve (not shown). After the engine starts, while the temperature of the engine cooling water 5 is low, the thermostat valve is closed, and the engine cooling water 5 pumped by the mechanical water pump 4 returns to the mechanical water pump 4 via the cylinder jacket 1a, the head jacket 1b, and the thermostat housing 6. The engine cooling water 5 bypasses the radiator 2, facilitating warm-up. When the temperature of the engine cooling water (5) rises and the thermostat valve opens, the engine cooling water (5) pumped by the mechanical water pump (4) passes through the cylinder jacket (1a), the head jacket (1b), the thermostat housing (6), and the radiator (2) before returning to the mechanical water pump (4), where the engine cooling water (5) is cooled by heat dissipation in the radiator (2).

[0017] In this engine, engine coolant 5 is used as a heat medium for a heat exchanger Pa of an engine-related part P. As shown in Fig. 3(A), this engine is equipped with a blow-by gas recirculation device 12 as an engine-related part P, which recirculates blow-by gas 10 in a crankcase 9 to an intake path 11, and as shown in Fig. 1, the blow-by gas recirculation device 12 is configured to be heated by engine coolant 5 passing through a heat exchanger 12a of the blow-by gas recirculation device 12.

[0018] As shown in FIG. 1, with this engine, even during a cold start when the engine speed is low and the mechanical water pump (4) is also running at a low speed, the electric water pump (7) can be driven at high speed without being affected by the engine speed, and the required amount of engine coolant (5) can be passed through the heat exchanger (12a) of the blow-by gas recirculation device (12) to heat the blow-by gas recirculation device (12), thereby preventing the water in the blow-by gas (10) from freezing in the blow-by gas recirculation device (12) during a cold start.

[0019] As shown in Figure 6(B), this engine is equipped with an oil separator (49) as a blow-by gas recirculation device (12) that separates oil (10a) from the blow-by gas (10), and is configured so that the oil separator (49) is heated by the engine coolant (5) that passes through a heat exchanger (49h) of the oil separator (49). This engine can prevent the water in the blow-by gas (10) from freezing in the oil separator (49) during cold start.

[0020] As shown in Figure 6(C), this engine is equipped with a PCV valve 50 and a blow-by gas recirculation passage 51 as a blow-by gas recirculation device 12, and is configured so that the PCV valve 50 and the blow-by gas recirculation passage 51 are heated by engine coolant 5 passing through a heat exchanger 50f of the PCV valve 50 and a heat exchanger (not shown) of the blow-by gas recirculation passage 51. This engine can prevent freezing of moisture in the blow-by gas 10 in the PCV valve 50 and the blow-by gas recirculation passage 51 during cold start. A heat exchanger may be provided in only one of the PCV valve 50 or the blow-by gas recirculation passage 51.

[0021] As shown in Figure 2, this engine is equipped with an electronic control device 13, which controls the operation of the electric water pump 7 and maintains the target rotation speed of the electric water pump 7 at a predetermined constant value. With this engine, because the target rotation speed of the electric water pump 7 is maintained at a predetermined constant value, even when the engine rotation speed slows and the mechanical water pump 4 also slows down, the rotation speed of the electric water pump 7 is maintained at a constant value without being affected by the engine rotation speed, and the required amount of engine coolant 5 passing through the heat exchanger 12a of the blow-by gas recirculation device 12 is obtained. Even when the temperature of the engine coolant 5 is low, the heat required to heat the blow-by gas recirculation device 12 can be dissipated from the heat exchanger 12a, preventing moisture in the blow-by gas 10 from freezing in the blow-by gas recirculation device 12 during cold start.

[0022] The thin arrows in Figure 2 between the electronic control unit 13 and components such as the electric water pump 7 indicate the signal paths and signal transmission directions between the electronic control unit 13 and components such as the electric water pump 7. As shown in Figure 2, this engine is equipped with a water temperature sensor 5a that detects the temperature of the engine coolant 5, and the electronic control unit 13, and the drive of the electric water pump 7 is controlled by the electronic control unit 13, and the rotation speed of the electric water pump 7 may be increased as the temperature of the engine coolant 5 detected by the water temperature sensor 5a decreases. In this case, even if the temperature of the engine coolant 5 is low, a predetermined flow rate of the engine coolant 5 passing through the heat exchanger 12a of the blow-by gas recirculation device 12 shown in Figure 1 can be obtained, and the heat required to heat the blow-by gas recirculation device 12 can be dissipated from the heat exchanger 12a, preventing the moisture in the blow-by gas 10 from freezing in the blow-by gas recirculation device 12 during cold start. The electronic control device 13 is the engine ECU. ECU is an abbreviation for electronic control unit.

[0023] As shown in FIG. 6(D), this engine is equipped with a urea water injector (16) as an engine-related part (P) that injects urea water (15) into the exhaust gas (14), and is configured so that the urea water injector (16) is cooled by the engine cooling water (5) that passes through a heat exchanger (16a) of the urea water injector (16).

[0024] With this engine, the urea water injector (16), which is heated by the exhaust gas (14), can be cooled by the engine coolant (5), thereby preventing overheating of the urea water injector (16). In addition, the heat absorbed by the engine coolant (5) when cooling the urea water injector (16) is dissipated by the blow-by gas recirculation device (12), thereby improving the heating efficiency of the blow-by gas recirculation device (12).

[0025] As shown in FIG. 7, this engine is equipped with a urea water tank (17) as an engine-related part (P), and is configured so that the urea water (15) in the urea water tank (17) is heated by the engine cooling water (5) passing through a heat exchanger (17a) of the urea water tank (17).

[0026] According to this engine, the urea water (15) in the urea water tank (17) is heated by the engine coolant (5), so that the urea water (15) frozen in the urea water tank (17) can be thawed during a cold start. Also, the heat absorbed by the engine coolant (5) when cooling the urea water injector (16) is dissipated to the urea water (15) in the urea water tank (17), so the urea water (15) in the urea water tank (17) is heated with high efficiency.

[0027] As shown in Fig. 2, this engine includes an electric valve (17b) that opens and closes the flow path of the engine coolant (5) passing through a heat exchanger (17a) of the urea water tank (17), a urea water temperature sensor (17c) that detects the temperature of the urea water (15) in the urea water tank (17), and an electronic control unit (13). In this engine, the electronic control unit (13) controls the opening and closing of the electric valve (17b). When the urea water temperature detected by the urea water temperature sensor (17c) is below a predetermined threshold value, indicating a state requiring heating, the electric valve (17b) is open. When the urea water temperature detected by the urea water temperature sensor (17c) is above the predetermined threshold value, indicating a state not requiring heating, the electric valve (17b) is closed. In this engine, when the urea water temperature is high, the electric valve (17b) is closed, so that the urea water (15) is not unnecessarily heated.

[0028] As shown in Figure 8, this engine is equipped with an air conditioner 18 as an engine-related part P, and is configured so that the air in a cabin 19 in which the air conditioner 18 is installed is heated by the engine coolant 5 passing through a heat exchanger 18a of the air conditioner 18. With this engine, the heat of the engine coolant 5 can be dissipated by the air conditioner 18, thereby heating the cabin 19. Furthermore, the heat absorbed by the engine coolant 5 when cooling the urea water injector 16 is dissipated by the air conditioner 18, so the heating efficiency of the air conditioner 18 is high.

[0029] As shown in FIG. 2, this engine is equipped with a solenoid valve (18b) that opens and closes the flow path of the engine coolant (5) that passes through a heat exchanger (18a) of the air conditioner (18), and an operation switch (18c) that operates the air conditioner (18). When the operation switch (18c) is turned to the operation position, the solenoid valve (18b) is in an open state, and when the operation switch (18c) is turned to the operation stop position, the solenoid valve (18b) is in a closed state.

[0030] As shown in Figure 2, this engine includes an electronic control device 13, a room temperature setting device 19a that sets a target room temperature in a cabin 19 equipped with an air conditioner 18, a room temperature sensor 19b that detects the room temperature in the cabin 19, a water temperature sensor 5a that detects the temperature of the engine coolant 5, and the electronic control device 13. When the operation switch 18c of the air conditioner 18 is turned to the operation position, the electronic control device 13 controls the opening of the solenoid valve 18b based on the set room temperature set by the room temperature setting device 19a, the detected room temperature detected by the room temperature sensor 19b, and the water temperature detected by the water temperature sensor 5a that detects the water temperature of the engine coolant 5, so that the room temperature in the cabin 19 approaches the set temperature.

[0031] As shown in FIG. 1, this engine is equipped with an iron-based foreign matter capture device (20) located upstream of the electric water pump (7) in the bypass water passage (B), and is configured so that iron-based foreign matter contained in the engine coolant (5) is captured by the iron-based foreign matter capture device (20).

[0032] As shown in Figure 1, with this engine, iron-based foreign matter such as iron rust generated in the main water channel (M) or bypass water channel (B) is captured by the iron-based foreign matter capture device (20) upstream of the bypass water channel (B) before it enters the electric water pump (7), thereby preventing the accumulation or entrapment of iron-based foreign matter inside the electric water pump (7).

[0033] Specific Example 1 of the ferrous foreign matter trapping device (20) shown in Figures 4(A) and (B) will be described. The ferrous foreign matter trapping device (20) of Specific Example 1 includes a bypass upstream waterway portion (21) constituting the upstream portion of the bypass waterway (B) and magnets (22) provided around the bypass upstream waterway portion (21), and is configured so that ferrous foreign matter is held within the bypass upstream waterway portion (21) by the magnetic force of the magnets (22).

[0034] The magnet 22 used in the ferrous foreign matter capture device 20 of Example 1 is a permanent magnet. The peripheral wall 21a of the bypass upstream waterway portion 21 of Example 1 is made of a magnetic metal.

[0035] The iron-based foreign matter capture device (20) of specific example 1 shown in Figures 4(A) and (B) comprises a bypass upstream waterway section (21), a magnet holder (22a) fitted onto the bypass upstream waterway section (21), and a magnet (22) housed in the magnet holder (22a), and the upstream end (21b) of the bypass upstream waterway section (21) is connected to the thermo outlet (6a) of the thermostat housing (6) via a thermo outlet side tube (6b), and the downstream end (21c) is connected to the cooling water inlet (7a) of the electric water pump (7) via a water pump inlet side tube (7b). The upstream end 21b of the bypass upstream waterway section 21 is detachably connected to the thermo outlet tube 6b, and the downstream end 21c is detachably connected to the water pump inlet tube 7b, so that the ferrous foreign matter capture device 20 can be removed from the bypass waterway B for cleaning or replacement. The magnet 22 may be an electromagnet. Magnetic metal materials used for the peripheral wall 21a of the bypass upstream waterway section 21 include iron, steel, nickel, cobalt, etc.

[0036] Two specific examples 2-1 and 2-2 of the iron-based foreign matter capture device 20 shown in Figures 5(A) and 5(C) will be described. The iron-based foreign matter capture device 20 of specific examples 2-1 and 2-2 includes a filter 23 that captures iron-based foreign matter.

[0037] According to these two specific examples 2-1 and 2-2 of the iron-based foreign matter capture device (20), iron-based foreign matter such as iron rust generated in the main water channel (M) or bypass water channel (B) shown in Figure 1 is captured in the filter (23) of the iron-based foreign matter capture device (20) upstream of the bypass water channel (B) before it enters the electric water pump (7), thereby preventing the accumulation and entrapment of iron-based foreign matter inside the electric water pump (7).

[0038] As shown in Figure 5(A), the iron-based foreign matter capture device (20) of specific example 2-1 is equipped with a flat filter (23a) as a filter (23) that crosses the bypass upstream waterway portion (21) that constitutes the upstream portion of the bypass waterway (B).

[0039] The iron-based foreign matter capture device (20) of specific example 2-1 comprises a bypass upstream waterway portion (21) and a flat filter (23a), the peripheral wall (21a) of the bypass upstream waterway portion (21) is made of rubber, the upstream end (21b) of the bypass upstream waterway portion (21) is connected to the thermo outlet (6a) of the thermostat housing (6), the downstream end (21c) is connected to the cooling water inlet (7a) of the electric water pump (7), and the flat filter (23a) is attached transversely to the cooling water inlet (7a) of the electric water pump (7). The upstream end (21b) of the bypass upstream waterway portion (21) is removably connected to the thermo outlet (6a) of the thermostat housing (6), and the downstream end (21c) is removably connected to the cooling water inlet (7a) of the electric water pump (7), so that the iron-based foreign matter capture device (20) can be removed from the bypass waterway (B) and cleaned or replaced.

[0040] As shown in Figure 5 (C), in the iron-based foreign matter capture device (20) of specific example 2-2, the filter (23) includes a cylindrical filter (23c) arranged in a filter case (23b) that communicates with the bypass upstream waterway portion (21) that constitutes the upstream portion of the bypass waterway (B).

[0041] As shown in Figure 5(C), in the iron-based foreign matter capture device (20) of specific example 2-2, the filter case (23b) is detachably attached to a mounting seat (24) that communicates with the bypass upstream water channel portion (21).

[0042] The mounting seat (24) is formed integrally with the bypass upstream water channel portion (21), and the upstream end (21b) of the bypass upstream water channel portion (21) is connected to the thermostat outlet (6a) of the thermostat housing (6) via the thermostat outlet side tube (6b), and the downstream end (21c) is connected to the cooling water inlet (7a) of the electric water pump (7) via the water pump inlet side tube (7b). The upstream end (21b) of the bypass upstream water channel portion (21) is detachably connected to the thermostat outlet side tube (6b), and the downstream end (21c) is detachably connected to the water pump inlet side tube (7b), so that the iron-based foreign matter capture device (20) can be removed from the bypass water channel (B) to clean or replace the iron-based foreign matter capture device (20).

[0043] In this engine, as needed, any one of the three specific examples of the ferrous contaminant trapping device (20) of Examples 1, 2-1, and 2-2 may be used alone, two or more of the three may be used, or three or more may be used. When Examples 1 and 2-1 are arranged in series, or when Examples 1 and 2-2 are arranged in series, it is desirable to arrange Example 1 on the upstream side of the flow path. The reason for this is as follows: Even if some of the ferrous contaminants trapped on the upstream side of the flow path by Example 1 are discharged downstream with the flow of the engine coolant (5), they are re-captured by the filters (23) of Examples 2-1 and 2-2 and are not re-released. This results in a high ferrous contaminant trapping ability, preventing the ferrous contaminants from being discharged to the electric water pump (7) or downstream thereof. Furthermore, most of the ferrous contaminants are captured by the upstream Example 1, and the downstream filters (23) of Examples 2-1 and 2-2 are less likely to clog, thereby extending the useful life of the filters (23).

[0044] The specific structure of the electric water pump 7 is as follows. As shown in Figure 6(A), the electric water pump 7 is a centrifugal pump comprising a pump housing 7c, a stator 7d, a rotor 7e, a pump chamber 7f, and an impeller 7g. A water pump inlet tube 7b is connected to the peripheral wall 21a of the bypass upstream water passage portion 21 of the ferrous foreign matter trapping device 20 or to the downstream side of the ferrous foreign matter trapping device 20, and a related component inlet tube 7k to each engine-related component P is connected to a cooling water outlet 7h of the pump chamber 7f. In this embodiment, all tubes are flexible, and both ends are removably connected to the inlets or outlets of the engine coolant 5 and blow-by gas 10 of each component.

[0045] In this engine, without the ferrous foreign matter capturing device (20), the magnetic force of the stator (7d) and rotor (7e) would cause ferrous foreign matter to stagnate in the pump chamber (7f), causing the ferrous foreign matter to stick together in the pump chamber (7f), or causing the ferrous foreign matter to become caught in the gap between the pump chamber (7f) and the impeller (7g) or between the stator (7d) and the rotor (7e), which would be prone to problems. However, with the ferrous foreign matter capturing device (20), the ferrous foreign matter is captured by the ferrous foreign matter capturing device (20) before it flows into the pump chamber (7f), making such problems less likely to occur.

[0046] This engine is equipped with an oil separator 49 shown in Fig. 6(B) and a PCV valve 50 shown in Fig. 6(C) as the blow-by gas recirculation device 12. The PCV valve 50 is disposed upstream of the blow-by gas recirculation path 34 shown in Fig. 3(A), and the oil separator 49 is disposed downstream of the blow-by gas recirculation path 34.

[0047] As shown in FIG. 6(B), the oil separator (49) includes a separator housing (49a), a blow-by gas swirl chamber (49b), a cylindrical oil filter (49c), and an oil drain chamber (49d). A blow-by gas inlet (49e) of the blow-by gas swirl chamber (49b) is connected to the PCV valve outlet-side tube (50a). A blow-by gas outlet (49ca) of the cylindrical oil filter (49c) is connected to the intake path (11) via a blow-by gas outlet-side tube (49cb). An oil outlet (49f) of the oil drain chamber (49d) communicates with the crankcase (9) via an oil outlet-side tube (49g). The oil (10a) in the oil drain chamber (49d) returns to the oil pan 30 via the crankcase (9).

[0048] As shown in Figure 6(B), the heat exchanger (49h) of the oil separator (49) is located below the oil drain chamber (49d), and the water inlet (49ha) of the heat exchanger (49h) is connected to the cooling water outlet (7h) of the electric water pump (7), and the water outlet (49hb) of the heat exchanger (49h) is connected to the cooling water inlet (4a) of the mechanical water pump (4).

[0049] In this engine, without the iron-based foreign matter capture device (20), problems such as iron-based foreign matter clumping inside the heat exchanger (49h) are likely to occur, whereas with the iron-based foreign matter capture device (20), such problems are less likely to occur because the iron-based foreign matter is captured by the iron-based foreign matter capture device (20) before it flows into the heat exchanger (49h).

[0050] As shown in FIG. 6(C), the PCV valve (50) includes a valve housing (50g), a valve body (50b), and a valve spring (50c). A blow-by gas inlet (50d) of the valve housing (50g) communicates with the cylinder head cover (27), and a blow-by gas outlet (50e) of the valve housing (50g) communicates with a blow-by gas swirl chamber (49b) of the oil separator (49) via a PCV valve outlet-side tube (50a).

[0051] As shown in FIG. 6(C), the heat exchanger 50f of the PCV valve 50 is disposed below the valve housing 50g, and the water inlet 50fa of the heat exchanger 50f is connected to the cooling water outlet 7h of the electric water pump 7, and the water outlet 50fb of the heat exchanger 50f is connected to the cooling water inlet 4a of the mechanical water pump 4.

[0052] In this engine, without the iron-based foreign matter capture device (20), problems such as iron-based foreign matter clumping inside the heat exchanger (50f) are likely to occur, whereas with the iron-based foreign matter capture device (20), such problems are less likely to occur because the iron-based foreign matter is captured by the iron-based foreign matter capture device (20) before it flows into the heat exchanger (50f).

[0053] The specific structure of the urea water injector 16 is as follows: As shown in Figure 6(D), the urea water injector 16 includes an injector housing 16b, an electromagnetic solenoid 16c, and a nozzle portion 16d.

[0054] As shown in FIG. 6(D), the heat exchanger 16a of the urea water injector 16 is formed around the nozzle portion 16d, and the water inlet 16aa of the heat exchanger 16a is connected to the cooling water outlet 7h of the electric water pump 7, and the water outlet 16ab of the heat exchanger 16a is connected to the cooling water inlet 4a of the mechanical water pump 4.

[0055] If this engine does not have an iron-based foreign matter capture device (20), the magnetic force of the electromagnetic solenoid (16c) will cause iron-based foreign matter to stagnate in the heat exchanger (16a), causing the iron-based foreign matter to stick inside the heat exchanger (16a), or the iron-based foreign matter to get caught in gaps inside the heat exchanger (16a), which can easily cause problems.However, if the iron-based foreign matter capture device (20) is present, the iron-based foreign matter is captured by the iron-based foreign matter capture device (20) before it flows into the heat exchanger (16a), making such problems less likely to occur.

[0056] The specific structure of the urea water tank 17 is as follows. As shown in Figure 7, the urea water 15 stored in the urea water tank 17 is supplied to the urea water injector 16 via a urea water pump 17d. A U-shaped heat exchanger 17a is disposed within the urea water tank 17, and a water inlet 17aa of the heat exchanger 17a communicates with the cooling water outlet 7h of the electric water pump 7 via an electric valve 17b, and a water outlet 17ab of the heat exchanger 17a communicates with the cooling water inlet 4a of the mechanical water pump 4.

[0057] In this engine, without the ferrous foreign matter capturing device (20), the magnetic force of the motor-operated valve (17b) would cause ferrous foreign matter to stagnate inside the motor-operated valve (17b), causing the ferrous foreign matter to stick inside the motor-operated valve (17b), or causing the ferrous foreign matter to become caught in gaps inside the motor-operated valve (17b), which would be prone to causing problems. However, with the ferrous foreign matter capturing device (20), the ferrous foreign matter is captured by the ferrous foreign matter capturing device (20) before it flows into the motor-operated valve (17b), making such problems less likely to occur.

[0058] The specific structure of the air conditioner 18 is as follows. As shown in Figure 8, the air conditioner 18 is located inside the cabin 19 and includes a heat exchanger 18a and an electric fan 18d. The water inlet 18aa of the heat exchanger 18a is connected to the cooling water outlet 7h of the electric water pump 7, and the water outlet 18ab of the heat exchanger 18a is connected to the cooling water inlet 4a of the mechanical water pump 4. A solenoid valve 18b that opens and closes the water passage of the heat exchanger 18a is located inside the air conditioner 18.

[0059] In this engine, without the iron-based foreign matter capture device (20), the magnetic force of the motor (8e) of the electric fan (18d) would cause iron-based foreign matter to stagnate in the heat exchanger (18a), causing the iron-based foreign matter to stick together in the heat exchanger (18a) or to become caught in gaps in the heat exchanger (18a), which would be prone to problems. However, with the iron-based foreign matter capture device (20), the iron-based foreign matter is captured by the iron-based foreign matter capture device (20) before it flows into the heat exchanger (18a), making such problems less likely to occur. Furthermore, in this engine, without the ferrous foreign matter capturing device (20), the magnetic force of the solenoid valve (18b) would cause ferrous foreign matter to stagnate inside the solenoid valve (18b), causing the ferrous foreign matter to stick inside the solenoid valve (18b), or causing the ferrous foreign matter to become caught in gaps inside the solenoid valve (18b), which would be prone to problems. However, with the ferrous foreign matter capturing device (20), the ferrous foreign matter is captured by the ferrous foreign matter capturing device (20) before it flows into the solenoid valve (18b), making such problems less likely to occur.

[0060] In this engine, as required, one or more engine-related parts (P) may be used selected from the group consisting of an oil separator (49) for the blow-by gas (10), a PCV valve (50), a blow-by gas recirculation passage (51), a urea water injector (16), a urea water tank (17) shown in FIG. 7, and an air conditioner (18) shown in FIG. 8, as shown in FIGS. 6(B) to 6(D).

[0061] (1)...Engine body, (2)...Radiator, (3)...Crankshaft, (4)...Mechanical water pump, (5)...Engine coolant, (5a)...Water temperature sensor, (M)...Main water passage, (7)...Electric water pump, (B)...Bypass water passage, (9)...Crankcase, (10)...Blow-by gas, (10a)...Oil, (11)...Intake path, (12)...Blow-by gas recirculation device, (12a)...Heat exchanger, (13)...Electronic control device, (14)...Exhaust, (15)...Urea water , (16)...urea water injector, (16a)...heat exchanger, (17)...urea water tank, (17a)...heat exchanger, (17b)...electric valve, (17c)...urea water temperature sensor, (18)...air conditioner, (18a)...heat exchanger, (18b)...solenoid valve, (18c)...operation switch, (19)...cabin, (19a)...room temperature setting device, (19b)...room temperature sensor, (49)...oil separator, (49h)...heat exchanger, (50)...PCV valve, (50f)...heat exchanger, (51)...blow-by gas return passage.

Claims

1. An engine comprising: an engine body; a radiator; a mechanical water pump driven by a crankshaft; a main water passage for circulating engine cooling water between the engine body and the radiator by the mechanical water pump to cool the engine body; engine-related components; a heat exchanger for the engine-related components; an electric water pump; and a bypass water passage for circulating engine cooling water between the main water passage and the heat exchanger for the engine-related components by the electric water pump, wherein the engine-related components include a blow-by gas reflux device for refluxing blow-by gas in a crankcase to an intake passage, and the blow-by gas reflux device is configured to be heated by engine cooling water passing through a heat exchanger of the blow-by gas reflux device.

2. The engine according to claim 1, wherein the blow-by gas reflux device includes an oil separator for separating oil from blow-by gas, and the oil separator is configured to be heated by engine cooling water passing through a heat exchanger of the oil separator.

3. The engine according to claim 1, wherein the blow-by gas reflux device includes a PCV valve and / or a blow-by gas reflux passage, and the PCV valve and / or the blow-by gas reflux passage are configured to be heated by engine cooling water passing through a heat exchanger of the PCV valve and / or the blow-by gas reflux passage.

4. The engine according to claim 1, further comprising an electronic control device, wherein the electronic control device controls the driving of the electric water pump such that a target rotational speed of the electric water pump is maintained at a predetermined constant value.

5. The engine according to claim 1, further comprising a water temperature sensor for detecting the temperature of engine cooling water and an electronic control device, wherein the electronic control device controls the driving of the electric water pump such that the rotational speed of the electric water pump increases as the temperature of the engine cooling water detected by the water temperature sensor decreases.

6. The engine according to claim 1, wherein the engine-related components include a urea water injector for injecting urea water into exhaust gas, and the urea water injector is configured to be cooled by engine cooling water passing through a heat exchanger of the urea water injector.

7. The engine according to claim 1, further comprising a urea aqueous solution tank as an engine-related component, wherein the urea aqueous solution in the urea aqueous solution tank is heated by engine cooling water passing through a heat exchanger of the urea aqueous solution tank.

8. The engine according to claim 7, further comprising an electric valve for opening and closing a flow path of the engine cooling water passing through the heat exchanger of the urea aqueous solution tank, a urea water temperature sensor for detecting the temperature of the urea aqueous solution in the urea aqueous solution tank, and an electronic control unit. The electric valve is controlled to open and close by the electronic control unit. When the temperature of the urea aqueous solution detected by the urea water temperature sensor is in a heating required state below a predetermined threshold value, the electric valve is in an open state. When the temperature of the urea aqueous solution detected by the urea water temperature sensor is in a heating unnecessary state exceeding the predetermined threshold value, the electric valve is in a closed state.

9. The engine according to claim 1, further comprising an air conditioner as an engine-related component, wherein the air in the cabin where the air conditioner is installed is heated by engine cooling water passing through a heat exchanger of the air conditioner.

10. The engine according to claim 9, further comprising a solenoid valve for opening and closing a flow path of the engine cooling water passing through the heat exchanger of the air conditioner, and an operation switch for operating the air conditioner. When the operation switch is turned to the operation position, the solenoid valve is in an open state. When the operation switch is turned to the operation stop position, the solenoid valve is in a closed state.

11. The engine according to claim 10, further comprising an electronic control unit, a room temperature setting device for setting a target room temperature in the cabin where the air conditioner is installed, a room temperature sensor for detecting the room temperature in the cabin, a water temperature sensor for detecting the temperature of the engine cooling water, and an electronic control unit. When the operation switch of the air conditioner is turned to the operation position, the opening degree of the solenoid valve is adjusted based on the set room temperature set by the room temperature setting device, the detected room temperature detected by the room temperature sensor, and the water temperature detected by the water temperature sensor for detecting the temperature of the engine cooling water under the control of the electronic control unit, so that the room temperature in the cabin approaches the set temperature.

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