Engine

Abstract

To provide an engine capable of preventing ferrous foreign matter from being accumulated or caught in an electric water pump 7.SOLUTION: An engine 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 mutually between a main water passage M and the heat exchanger Pa of the engine related component P by the electric water pump 7, and further includes a ferrous foreign matter capture device 20 arranged in an upstream side of the bypass water passage B relative to the electric water pump 7. The ferrous foreign matter contained in the engine cooling water 5 is captured by the ferrous foreign matter capture device 20, and the ferrous foreign matter capture device 20 includes a magnet to capture the ferrous foreign matter.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an engine, and more particularly to an engine capable of preventing deposition and jamming of iron-based foreign matter in an electric water pump.

Background Art

[0002] Conventionally, there has been an engine including an engine body, a main water passage for circulating engine cooling water for cooling the engine body, an electric water pump, and a bypass water passage for circulating engine cooling water between the main water passage and a heat exchanger of a urea water injector by the electric water pump (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] <<Problems>> Iron-based foreign matter is likely to accumulate and jam in the electric water pump. In the engine of Patent Document 1, iron-based foreign matter such as iron rust generated in the main water passage or the bypass water passage enters the electric water pump together with the engine cooling water and stagnates due to the magnetic force of the motor of the electric water pump. Therefore, iron-based foreign matter is likely to accumulate and jam in the electric pump.

[0005] An object of the present invention is to provide an engine capable of preventing deposition and jamming of iron-based foreign matter in the electric pump.

Means for Solving the Problems

[0006] The main configuration of the present invention is as follows. As illustrated in FIG. 1, an engine main body (1), a radiator (2), a mechanical water pump (4) driven by a crankshaft (3), a main water passage (M) for circulating engine cooling water (5) between the engine main body (1) and the radiator (2) by the mechanical water pump (4) to cool the engine main body (1), engine-related components (P), a heat exchanger (Pa) of the engine-related components (P), an electric water pump (7), and a bypass water passage (B) for circulating the engine cooling water (5) between the main water passage (M) and the heat exchanger (Pa) of the engine-related components (P) by the electric water pump (7), and an iron-based foreign matter capturing device (20) disposed upstream of the bypass water passage (B) from the electric water pump (7), and configured such that iron-based foreign matter contained in the engine cooling water (5) is captured by the iron-based foreign matter capturing device (20). An engine characterized by this.

Advantages of the Invention

[0007] The present invention has the following effects. 《Effect》 It is possible to prevent the deposition and jamming of iron-based foreign matter in the electric water pump (7). This can be done. According to this engine, before iron-based foreign matter such as iron rust generated in the main water passage (M) and the bypass water passage (B) illustrated in FIG. 1 enters the electric water pump (7), it is captured by the iron-based foreign matter capturing device (20) upstream of the bypass water passage (B). Therefore, it is possible to prevent the deposition and jamming of iron-based foreign matter in the electric water pump (7).

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0009] FIGS. 1 to 9 are diagrams 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.

[0010] As shown in Fig. 9, the engine body (1) of this engine includes a cylinder block (25), a cylinder head (26) assembled on the upper part of the cylinder block (25), a cylinder head cover (27) assembled on the upper part of the cylinder head (26), an engine cooling fan (28) arranged on the front side of the cylinder block (25) with the installation direction of the crankshaft (3) being the front-rear direction and one side of the front-rear direction being the front side, a flywheel housing (29) assembled on the rear side of the cylinder block (25), and an oil pan (30) assembled on the lower side of the cylinder block (25). The cylinder block (25) includes a downwardly inclined crankcase (9) and an upwardly inclined cylinder part (31), and the crankshaft (3) is installed in the crankcase (9). As shown in Fig. 7, when viewed in a direction parallel to the front-rear direction, with the width direction of the engine body (1) perpendicular to the front-rear direction and the up-down direction being the lateral direction, an intake manifold (32) is assembled on one lateral side of the cylinder head (26), and an exhaust manifold (33) is assembled on the other lateral side of the cylinder head (26).

[0011] The engine body (1) includes an intake passage (11) shown in Fig. 3(A), a blow-by gas reflux passage (34), a fuel supply device (35) shown in Fig. 7, an exhaust passage (36) shown in Fig. 3(B), a urea aqueous solution passage (37), and a water cooling device (38) shown in Fig. 1. The arrows in Fig. 3(A) indicate the piping and flow directions of the intake air (11a) or the blow-by gas (10). The configuration of the intake passage (11) is as follows. As shown in Fig. 3(A), the intake passage (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 then supercharged into the combustion chamber (not shown) through the intake throttle (41) and the intake manifold (32).

[0012] As shown in Fig. 3(A), the blow-by gas reflux path (34) is of a PCV system including a crankcase (9), a cylinder head cover (27), and a blow-by gas reflux device (12). The end of the blow-by gas reflux path (34) is connected to the intake path (11) between the air cleaner (39) and the air compressor (40a). The blow-by gas (10) generated in the crankcase (9) is refluxed to the intake path (11) through the cylinder head cover (27) and the blow-by gas reflux device (12). PCV is the abbreviation of Positive Crankcase Ventilation.

[0013] The fuel supply device (not shown) is equipped with a common rail type fuel injection device using a common rail (not shown), and supplies the fuel accumulated in the common rail from a fuel injector (not shown) to each combustion chamber.

[0014] The arrows in Fig. 3(B) indicate the piping and flow directions of the exhaust gas (14) or the aqueous urea solution (15). The configurations of the exhaust path (36) and the aqueous urea solution path (37) are as follows. As shown in Fig. 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 aqueous urea solution path (37) includes an aqueous urea solution tank (17), an aqueous urea solution pump (17d), and an aqueous urea solution injector (16). The aqueous urea solution injector (16) adds the aqueous urea solution (15) to the exhaust gas (14) between the DPF (45) and the SCR (46), and reduces NO x (nitrogen oxides) to N2 (nitrogen gas) and H2O (water vapor). The NH3 (ammonia) that slips through the SCR (46) is purified by the ASC (47). DOC is the abbreviation of Diesel Oxidation Catalyst, DPF is the abbreviation of Diesel Particulate Filter, SCR is the abbreviation of Selective Catalytic Reduction type catalyst, and ASC is the abbreviation of Ammonia Scrubbing Oxidation Catalyst. Note that, in Figs. 3(B), 7 to 9, the reference numeral (52) indicates a DPF housing case that houses the DOC (44) and DPF (45), and the reference numeral (53) indicates an SCR housing case that houses the SCR (46) and ASC (47).

[0015] The configuration of the water cooling device (38) is as follows. As shown in Fig. 1, this 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) that circulates engine cooling water (5) between the engine body (1) and the radiator (2) by means of the mechanical water pump (4) to cool the engine body (1). In addition, this engine includes engine-related components (P), a heat exchanger (Pa) for the engine-related components (P), an electric water pump (7), and a bypass water passage (B) that circulates engine cooling water (5) between the main water passage (M) and the heat exchanger (Pa) of the engine-related components (P) by means of the electric water pump (7).

[0016] The arrows in Fig. 1 indicate the water passages and the flowing directions of the engine cooling water (5). The configuration of the main water passage (M) is as follows. As shown in Fig. 1, the main water passage (M) includes a cylinder jacket (1a) that surrounds a cylinder (not shown), a head jacket (1b) provided inside the cylinder head (26), and a thermostat housing (6) that houses a thermostat valve (not shown). After the engine starts, while the water 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) flows through the cylinder jacket (1a), the head jacket (1b), and the thermostat housing (6) and then returns to the mechanical water pump (4). By bypassing the radiator (2), the warm-up of the engine is promoted. When the water temperature of the engine coolant (5) rises and the thermostat valve opens, the engine coolant (5) pumped by the mechanical water pump (4) flows through the cylinder jacket (1a), the head jacket (1b), the thermostat housing (6), and the radiator (2) and then returns to the mechanical water pump (4). The engine coolant (5) is cooled by heat dissipation in the radiator (2).

[0017] In this engine, engine coolant (5) is used as the heat medium of the heat exchanger (Pa) of the engine-related parts (P). As shown in Fig. 3(A), this engine includes, as engine-related parts (P), a blow-by gas reflux device (12) that refluxes the blow-by gas (10) in the crankcase (9) to the intake passage (11). As shown in Fig. 1, the blow-by gas reflux device (12) is configured to be heated by the engine coolant (5) passing through the heat exchanger (12a) of the blow-by gas reflux device (12).

[0018] As shown in Fig. 1, according to this engine, even at cold start when the engine speed is low and the mechanical water pump (4) rotates at a low speed, the electric water pump (7) that can be driven at high speed without being affected by the engine speed allows the required amount of engine coolant (5) to pass through the heat exchanger (12a) of the blow-by gas reflux device (12), and the blow-by gas reflux device (12) can be heated. Therefore, icing of the moisture in the blow-by gas (10) in the blow-by gas reflux device (12) can be prevented at cold start.

[0019] As shown in Fig. 6(B), this engine includes, as the blow-by gas reflux device (12), an oil separator (49) that separates oil (10a) from the blow-by gas (10). The oil separator (49) is configured to be heated by the engine coolant (5) passing through the heat exchanger (49h) of the oil separator (49). According to this engine, icing of the moisture in the blow-by gas (10) in the oil separator (49) can be prevented at cold start.

[0020] As shown in FIG. 6(C), this engine includes a PCV valve (50) and a blow-by gas reflux passage (51) as a blow-by gas reflux device (12), and engine cooling water (5) passing through a heat exchanger (50f) of the PCV valve (50) and a heat exchanger (not shown) of the blow-by gas reflux passage (51) is configured to heat the PCV valve (50) and the blow-by gas reflux passage (51). According to this engine, it is possible to prevent freezing of moisture in the blow-by gas (10) in the PCV valve (50) and the blow-by gas reflux passage (51) during cold start. Only one of the PCV valve (50) or the blow-by gas reflux passage (51) may be provided with a heat exchanger.

[0021] As shown in FIG. 2, this engine includes an electronic control unit (13), and the driving of the electric water pump (7) is controlled by the electronic control unit (13) so that the target rotational speed of the electric water pump (7) is maintained at a predetermined constant value. According to this engine, since the target rotational speed of the electric water pump (7) is maintained at a predetermined constant value, even when the engine rotational speed becomes low and the mechanical water pump (4) rotates at a low speed, the rotational speed of the electric water pump (7) is maintained at a constant value without being affected by the engine rotational speed, and the required amount of engine cooling water (5) passing through the heat exchanger (12a) of the blow-by gas reflux device (12) can be obtained. Even when the water temperature of the engine cooling water (5) is low, the heat required for heating the blow-by gas reflux device (12) can be dissipated from the heat exchanger (12a), and it is possible to prevent moisture in the blow-by gas (10) from freezing in the blow-by gas reflux device (12) during cold start.

[0022] The thin-line arrows shown between the electronic control unit (13) and components such as the electric water pump (7) in FIG. 2 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 FIG. 2, this engine includes a water temperature sensor (5a) that detects the temperature of engine cooling water (5) and an electronic control unit (13). The driving of the electric water pump (7) is controlled by the electronic control unit (13). The lower the water temperature of the engine cooling water (5) detected by the water temperature sensor (5a), the higher the rotational speed of the electric water pump (7) may be configured. In this case, even when the water temperature of the engine cooling water (5) is low, a predetermined flow rate of the engine cooling water (5) passing through the heat exchanger (12a) of the blow-by gas reflux device (12) shown in FIG. 1 can be obtained, and the heat required for heating the blow-by gas reflux device (12) can be dissipated from the heat exchanger (12a). It is possible to prevent the moisture in the blow-by gas (10) from freezing in the blow-by gas reflux device (12) during cold start. The electronic control unit (13) is an engine ECU. ECU is an abbreviation for electronic control unit.

[0023] As shown in FIG. 6(D), this engine includes, as engine-related components (P), a urea water injector (16) that injects urea water (15) into the exhaust gas (14), and is configured such that the engine cooling water (5) passing through the heat exchanger (16a) of the urea water injector (16) cools the urea water injector (16).

[0024] According to this engine, since the urea water injector (16) heated by the exhaust gas (14) can be cooled by the engine cooling water (5), overheating of the urea water injector (16) can be prevented. In addition, since the heat absorbed by the engine cooling water (5) during cooling of the urea water injector (16) is dissipated by the blow-by gas reflux device (12), the heating efficiency of the blow-by gas reflux device (12) is high.

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

[0026] According to this engine, since the engine coolant water (5) heats the aqueous urea solution (15) in the aqueous urea solution tank (17), it is possible to thaw the aqueous urea solution (15) frozen in the aqueous urea solution tank (17) during cold start. Also, since the heat absorbed by the engine coolant water (5) during the cooling of the aqueous urea solution injector (16) is radiated to the aqueous urea solution (15) in the aqueous urea solution tank (17), the heating efficiency of the aqueous urea solution (15) in the aqueous urea solution tank (17) is high.

[0027] As shown in FIG. 2, this engine includes an electric valve (17b) that opens and closes the flow path of the engine coolant water (5) passing through the heat exchanger (17a) of the aqueous urea solution tank (17), a urea water temperature sensor (17c) that detects the temperature of the aqueous urea solution (15) in the aqueous urea solution tank (17), and an electronic control unit (13). In this engine, the electric valve (17b) is controlled to open and close by the electronic control unit (13). When the temperature of the aqueous urea solution detected by the urea water temperature sensor (17c) is in a heating required state below a predetermined threshold value, the electric valve (17b) is in an open state. When the temperature of the aqueous urea solution detected by the urea water temperature sensor (17c) is in a heating not required state exceeding the predetermined threshold value, the electric valve (17b) is configured to be in a closed state. According to this engine, when the temperature of the aqueous urea solution is high, the electric valve (17b) is in a closed state, so the aqueous urea solution (15) is not heated wastefully.

[0028] As shown in FIG. 8, this engine includes an air conditioner (18) as an engine related component (P), and the air in the cabin (19) where the air conditioner (18) is installed is heated by the engine coolant water (5) passing through the heat exchanger (18a) of the air conditioner (18). According to this engine, since the heat of the engine coolant water (5) can be radiated by the air conditioner (18), heating in the cabin (19) can be performed. Also, since the heat absorbed by the engine coolant water (5) during the cooling of the aqueous urea solution injector (16) is radiated by the air conditioner (18), the heating efficiency of the air conditioner (18) is high.

[0029] As shown in FIG. 2, this engine includes a solenoid valve (18b) that opens and closes a flow path of engine cooling water (5) passing through a heat exchanger (18a) of an air conditioner (18), and an operation switch (18c) that operates the air conditioner (18). When the operation switch (18c) is turned on to the operation position, the solenoid valve (18b) is opened, and when the operation switch (18c) is turned off to the operation stop position, the solenoid valve (18b) is closed.

[0030] As shown in FIG. 2, this engine includes an electronic control unit (13), a room temperature setting device (19a) that sets a target room temperature in a cabin (19) where an air conditioner (18) is installed, a room temperature sensor (19b) that detects the room temperature in the cabin (19), a water temperature sensor (5a) that detects the temperature of engine cooling water (5), and an electronic control unit (13). When the operation switch (18c) of the air conditioner (18) is turned on to the operation position, the opening degree of the solenoid valve (18b) is adjusted 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 cooling water (5) under the control of the electronic control unit (13), so that the room temperature in the cabin (19) approaches the set temperature.

[0031] As shown in FIG. 1, this engine includes an iron-based foreign matter capturing device (20) disposed upstream of a bypass water passage (B) with respect to an electric water pump (7), and is configured such that iron-based foreign matter contained in the engine cooling water (5) is captured by the iron-based foreign matter capturing device (20).

[0032] As shown in FIG. 1, according to this engine, before iron-based foreign matter such as iron rust generated in the main water passage (M) or the bypass water passage (B) enters the electric water pump (7), it is captured by the iron-based foreign matter capturing device (20) upstream of the bypass water passage (B), so that deposition and jamming of iron-based foreign matter in the electric water pump (7) can be prevented.

[0033] A specific example 1 of the iron-based foreign matter capturing device (20) shown in FIGS. 4(A) and (B) will be described. The iron foreign object capturing device (20) of Specific Example 1 includes a bypass upstream water channel portion (21) that constitutes an upstream portion of the bypass water channel (B) and a magnet (22) provided around the bypass upstream water channel portion (21), and is configured such that iron foreign objects are held in the bypass upstream water channel portion (21) by the magnetic force of the magnet (22).

[0034] The magnet (22) used in the iron foreign object capturing device (20) of Specific Example 1 is a permanent magnet. Further, the peripheral wall (21a) of the bypass upstream water channel portion (21) of Specific Example 1 is made of a magnetic metal.

[0035] The iron foreign object capturing device (20) of Specific Example 1 shown in FIGS. 4(A) and (B) includes a bypass upstream water channel portion (21), a magnet holder (22a) externally fitted to the bypass upstream water channel portion (21), and a magnet (22) housed in the magnet holder (22a). The upstream end portion (21b) of the bypass upstream water channel portion (21) is connected to the thermo outlet (6a) of the thermostat housing (6) via a thermo outlet side tube (6b), and the downstream end portion (21c) communicates with the cooling water inlet (7a) of the electric water pump (7) via a water pump inlet side tube (7b). The upstream end portion (21b) of the bypass upstream water channel portion (21) is detachably connected to the thermo outlet side tube (6b), and the downstream end portion (21c) is detachably connected to the water pump inlet side tube (7b), so that the iron foreign object capturing device (20) can be removed from the bypass water channel (B) to clean or replace the iron foreign object capturing device (20). The magnet (22) may be an electromagnet. Examples of the magnetic metal material used for the peripheral wall (21a) of the bypass upstream water channel portion (21) include iron, steel, nickel, cobalt, and the like.

[0036] Two specific examples 2-1 and 2-2 of the iron foreign object capturing device (20) shown in FIGS. 5(A) and (C) will be described. The iron foreign object capturing devices (20) of Specific Examples 2-1 and 2-2 include a filter (23) for capturing iron foreign objects.

[0037] According to these two types of iron foreign matter capture devices (20) of specific examples 2-1 and 2-2, before iron foreign matters such as iron rust generated in the main water passage (M) and the bypass water passage (B) shown in FIG. 1 enter the electric water pump (7), they are captured by the filter (23) of the iron foreign matter capture device (20) on the upstream side of the bypass water passage (B). Therefore, it is possible to prevent the accumulation and jamming of iron foreign matters in the electric water pump (7).

[0038] As shown in FIG. 5(A), the iron foreign matter capture device (20) of specific example 2-1 includes a flat filter (23a) that crosses the bypass upstream water passage portion (21) constituting the upstream side portion of the bypass water passage (B) as the filter (23).

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

[0040] As shown in FIG. 5(C), in the iron foreign matter capture device (20) of specific example 2-2, the filter (23) includes a cylindrical filter (23c) disposed in a filter case (23b) that communicates with the bypass upstream water passage portion (21) constituting the upstream side portion of the bypass water passage (B).

[0041] As shown in FIG. 5(C), in the iron foreign matter capturing device (20) of Specific Example 2-2, the filter case (23b) is detachably attached to an attachment seat (24) that communicates with the bypass upstream water passage portion (21).

[0042] The attachment seat (24) is integrally formed with the bypass upstream water passage portion (21). The upstream end portion (21b) of the bypass upstream water passage portion (21) is connected to the thermo outlet (6a) of the thermostat housing (6) via a thermo outlet side tube (6b), and the downstream end portion (21c) communicates with the cooling water inlet (7a) of the electric water pump (7) via a water pump inlet side tube (7b). The upstream end portion (21b) of the bypass upstream water passage portion (21) is detachably connected to the thermo outlet side tube (6b), and the downstream end portion (21c) is detachably connected to the water pump inlet side tube (7b). The iron foreign matter capturing device (20) can be removed from the bypass water passage (B) so that the iron foreign matter capturing device (20) can be cleaned or replaced.

[0043] In this engine, as needed, among the three specific examples of the iron foreign matter capturing device (20) of Specific Examples 1, 2-1, and 2-2, any one type can be used alone, any two types can be used in plurality, or three types can be used in plurality. When arranging Specific Examples 1 and 2-1 in series, or when arranging Specific Examples 1 and 2-2 in series, it is desirable to arrange Specific Example 1 on the upstream side of the flow path. The reason is as follows. Even if some of the iron foreign matter captured on the upstream side of the flow path by Specific Example 1 is discharged downstream by the water flow of the engine cooling water (5), it is re-captured by the filters (23) of Specific Examples 2-1 and 2-2 and is not re-discharged. Therefore, the capturing performance of iron foreign matter is high, the iron foreign matter is not discharged to the electric water pump (7) or the downstream side thereof, and most of the iron foreign matter is captured by Specific Example 1 on the upstream side. The filters (23) of Specific Examples 2-1 and 2-2 on the downstream side are less likely to be clogged, so the service life of the filters (23) is prolonged.

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

[0045] In this engine, without the iron foreign matter capture device (20), iron foreign matters may stagnate in the pump chamber (7f) due to the magnetic force of the stator (7d) and rotor (7e), and the iron foreign matters may adhere in the pump chamber (7f), or problems such as the iron foreign matters getting stuck in the gap between the pump chamber (7f) and the impeller (7g) or between the stator (7d) and the rotor (7e) are likely to occur. On the contrary, with the iron foreign matter capture device (20), the iron foreign matters are captured by the iron foreign matter capture device (20) before flowing into the pump chamber (7f), so such problems are less likely to occur.

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

[0047] As shown in Fig. 6(B), the oil separator (49) includes a separator housing (49a), a blow-by gas swirling chamber (49b), a cylindrical oil filter (49c), and an oil drain chamber (49d). The blow-by gas inlet (49e) of the blow-by gas swirling chamber (49b) is connected to the PCV valve outlet side tube (50a). The blow-by gas outlet (49ca) of the cylindrical oil filter (49c) is connected to the intake passage (11) via the blow-by gas outlet side tube (49cb). The oil outlet (49f) of the oil drain chamber (49d) communicates with the crankcase (9) via the 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 Fig. 6(B), the heat exchanger (49h) of the oil separator (49) is disposed below the oil drain chamber (49d). The water inlet (49ha) of the heat exchanger (49h) communicates with the cooling water outlet (7h) of the electric water pump (7). The water outlet (49hb) of the heat exchanger (49h) communicates with the cooling water inlet (4a) of the mechanical water pump (4).

[0049] In this engine, without the iron-based foreign matter capturing device (20), problems such as adhesion of iron-based foreign matter in the heat exchanger (49h) are likely to occur. On the other hand, with the iron-based foreign matter capturing device (20), the iron-based foreign matter is captured by the iron-based foreign matter capturing device (20) before flowing into the heat exchanger (49h), so such problems are less likely to occur.

[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). The blow-by gas inlet (50d) of the valve housing (50g) communicates with the cylinder head cover (27). The blow-by gas outlet (50e) of the valve housing (50g) communicates with the blow-by gas swirling chamber (49b) of the oil separator (49) via the 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). The water inlet (50fa) of the heat exchanger (50f) communicates with the cooling water outlet (7h) of the electric water pump (7), and the water outlet (50fb) of the heat exchanger (50f) communicates with the cooling water inlet (4a) of the mechanical water pump (4).

[0052] In this engine, without the iron-based foreign matter capturing device (20), problems such as adhesion of iron-based foreign matter in the heat exchanger (50f) are likely to occur. On the contrary, with the iron-based foreign matter capturing device (20), since the iron-based foreign matter is captured by the iron-based foreign matter capturing device (20) before flowing into the heat exchanger (50f), such problems are less likely to occur.

[0053] The specific structure of the urea water injector (16) is as follows. As shown in FIG. 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). 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] In this engine, when there is no iron-based foreign matter capturing device (20), iron-based foreign matter stagnates in the heat exchanger (16a) due to the magnetic force of the electromagnetic solenoid (16c), and problems such as adhesion of iron-based foreign matter in the heat exchanger (16a) or jamming of iron-based foreign matter in the gaps in the heat exchanger (16a) are likely to occur. On the contrary, when there is an iron-based foreign matter capturing device (20), since the iron-based foreign matter is captured by the iron-based foreign matter capturing device (20) before flowing into the heat exchanger (16a), such problems are less likely to occur.

[0056] The specific structure of the urea water tank (17) is as follows. As shown in FIG. 7, the aqueous urea (15) stored in the aqueous urea tank (17) is supplied to the aqueous urea injector (16) via the aqueous urea pump (17d). A U-shaped heat exchanger (17a) is disposed in the aqueous urea tank (17). The water inlet (17aa) of the heat exchanger (17a) communicates with the cooling water outlet (7h) of the electric water pump (7) via the electric valve (17b), and the 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 iron-based foreign matter capturing device (20), iron-based foreign matter tends to stagnate in the electric valve (17b) due to the magnetic force of the electric valve (17b), the iron-based foreign matter adheres in the electric valve (17b), or the iron-based foreign matter bites into the gap in the electric valve (17b). On the contrary, with the iron-based foreign matter capturing device (20), the iron-based foreign matter is captured by the iron-based foreign matter capturing device (20) before flowing into the electric valve (17b), so such problems are less likely to occur.

[0058] The specific structure of the air conditioner (18) is as follows. As shown in FIG. 8, the air conditioner (18) is disposed in the cabin (19) and includes a heat exchanger (18a) and an electric fan (18d). The water inlet (18aa) of the heat exchanger (18a) communicates with the cooling water outlet (7h) of the electric water pump (7), and the water outlet (18ab) of the heat exchanger (18a) communicates with the cooling water inlet (4a) of the mechanical water pump (4). Further, the solenoid valve (18b) for opening and closing the water passage of the heat exchanger (18a) is disposed inside the air conditioner (18).

[0059] In this engine, without the iron-based foreign matter capturing device (20), iron-based foreign matter tends to stagnate in the heat exchanger (18a) due to the magnetic force of the motor (8e) of the electric fan (18d), the iron-based foreign matter adheres in the heat exchanger (18a), or the iron-based foreign matter bites into the gap in the heat exchanger (18a). On the contrary, with the iron-based foreign matter capturing device (20), the iron-based foreign matter is captured by the iron-based foreign matter capturing device (20) before flowing into the heat exchanger (18a), so such problems are less likely to occur. Also, in this engine, without the iron-based foreign matter capturing device (20), iron-based foreign matter may stagnate inside the solenoid valve (18b) due to the magnetic force of the solenoid valve (18b), the iron-based foreign matter may adhere inside the solenoid valve (18b), or the iron-based foreign matter may bite into the gap inside the solenoid valve (18b), etc. On the other hand, with the iron-based foreign matter capturing device (20), the iron-based foreign matter is captured by the iron-based foreign matter capturing device (20) before flowing into the solenoid valve (18b), so such problems are less likely to occur.

[0060] In this engine, as needed, as engine-related parts (P), one or more selected from the oil separator (49) of the blow-by gas (10), the PCV valve (50), the blow-by gas recirculation passage (51), the urea water injector (16), the urea water tank (17) shown in FIG. 7, and the air conditioner (18) shown in FIG. 8 can be used.

Explanation of Signs

[0061] (1)…Engine body, (2)…Radiator, (3)…Crankshaft, (4)…Mechanical water pump, (5)…Engine cooling water, (5a)…Cooling water temperature sensor, (M)…Main waterway, (7)…Electric water pump, (B)…Bypass waterway, (9)…Crankcase, (10)…Blow-by gas, (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)…Cab, (19a)…Room temperature setting device, (19b)…Room temperature sensor, (20)…Iron-based foreign matter capturing device, (21)…Bypass upstream waterway part, (21a)…Peripheral wall, (22)…Magnet, (50)…PCV valve, (51)…Blow-by gas recirculation passage.

Claims

1. An engine body (1), a radiator (2), a mechanical water pump (4) driven by a crankshaft (3), a main waterway (M) for circulating engine cooling water (5) between the engine body (1) and the radiator (2) by the mechanical water pump (4) to cool the engine body (1), engine-related components (P), a heat exchanger (Pa) of the engine-related components (P), an electric water pump (7), and a bypass waterway (B) for circulating the engine cooling water (5) between the main waterway (M) and the heat exchanger (Pa) of the engine-related components (P) by the electric water pump (7), comprising an iron-based foreign matter capturing device (20) disposed upstream of the bypass waterway (B) with respect to the electric water pump (7), and configured such that iron-based foreign matter contained in the engine cooling water (5) is captured by the iron-based foreign matter capturing device (20). An engine characterized by this.

2. In the engine according to Claim 1, the iron-based foreign matter capturing device (20) includes a bypass upstream waterway portion (21) constituting an upstream portion of the bypass waterway (B) and a magnet (22) provided around the bypass upstream waterway portion (21), and is configured such that iron-based foreign matter is held in the upstream waterway portion (21) by the magnetic force of the magnet (22). An engine characterized by this.

3. In the engine according to Claim 2, the magnet (22) is a permanent magnet. An engine characterized by this.

4. In the engine according to Claim 2, the peripheral wall (21a) of the bypass upstream waterway portion (21) is made of a metal having magnetism. An engine characterized by this.

5. In the engine according to Claim 1, as the engine-related components (P), it is provided with one or more components selected from an oil separator (49) for 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), and an air conditioner (18). An engine characterized by this.

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