This application is a national phase entry under 35 U.S.C. § 371 of PCT Patent Application No. PCT/JP2018/043388, filed on Nov. 26, 2018, which claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2017-240460, filed Dec. 15, 2017, both of which are incorporated by reference.
The present invention relates to an engine having an oil cooler accommodated inside a cylinder block thereof.
There has been known an engine having an oil cooler for cooling an engine oil accommodated in a cylinder block thereof.
To facilitate heat exchanging of an oil cooler element, the following Patent Literature 1 (hereinafter, PTL 1) describes a structure in which cooling water is supplied from a lower portion to an upper portion of end portions relative to a horizontal direction so that the cooling water spreads the entire oil cooler element. However, in general, support members are provided to support an oil inflow port and an oil ejection port at both end portions of the oil cooler element relative to the horizontal direction. The cooling water therefore may collide with the support members and may not be efficiently supplied to the oil cooler element.
PTL 1: Japanese Examined Utility Model Publication No. H7-655 (1995)
In view of the above described problem, an object of the present invention is to provide an engine that can efficiently supply cooling water to the oil cooler.
An aspect of the present invention is an engine including a cylinder block in which a cooling water passage is formed;
an oil cooler accommodated in an accommodation space provided in the cooling water passage and having a plurality of cores for cooling an engine oil;
a pair of support members configured to support an oil inflow port and an oil ejection port of each of the cores;
a cooling water inflow port provided in a lower portion of one end portion of the accommodation space relative to a front-and-rear direction;
a cooling water outflow port provided in an upper portion of the accommodation space; and
a cooling water inflow passage having an inclined portion inclined downward and connecting to the cooling water inflow port.
With the above aspect of the present invention, the cooling water passing the inclined portion of the cooling water inflow passage creates a downward flow, resulting in the downward flow of the cooling water to flow from the cooling water inflow port into the accommodation space. Therefore, the cooling water can be efficiently supplied to the entire oil cooler without colliding with the support members.
The above aspect of the present invention may be adapted such that the cooling water inflow passage has an upper protrusion protruding downward from an upper passage wall and a lower protrusion protruding upward from a lower passage wall.
The upper protrusion is arranged closer to the oil cooler than the lower protrusion.
With this structure, the cooling water flowing in the cooling water inflow passage collides with the upper protrusion and flows downward. Therefore, the cooling water does not collide with the support members.
The above aspect of the present invention may be adapted such that a wax pellet that expands or shrinks depending on a temperature of the cooling water is arranged between the oil cooler and a side wall of the accommodation space.
In this structure, the wax pellet shrinks in an occasion such as when the engine is started and the like, in which occasion the temperature of lubrication oil is low. This causes the cooling water to flow into a gap between the wax pellet and the accommodation space, and resulting in a less amount of cooling water flowing between the cores. Therefore, a quick warm up of the engine can be possible. On the other hand, when the temperature of the lubrication oil is high, the wax pellet expands and fills the gap between the wax pellet and the side wall of the accommodation space. This increases the amount of cooling water flowing between the cores, and sufficient heat exchanging of the oil cooler can be achieved.
The above aspect of the present invention may be adapted such that the cooling water inflow passage includes a current plate.
The cooling water ejected from the cooling water pump may form a strong swirl flow. When such a strong swirl flow occurs, the amount of cooling water between the cores decreases, and heat exchanging efficiency of the oil cooler may be deteriorated. With the current plate, however, the swirl flow can be suppressed, and the amount of cooling water flowing between the cores increases. Therefore, the heat exchanging of the oil cooler can be efficient.
The above aspect of the present invention may be adapted such that a protrusion protruding upward is arranged between the pair of support members constituting a bottom surface of the accommodation space.
With the protrusion, the cooling water flowing nearby the bottom surface of the accommodation space collides with the protrusion, increasing the rate of the cooling water flowing to a middle portion of the oil cooler relative to the front-and-rear direction. Therefore, the cooling efficiency can be improved.
In the following, an embodiment of the present invention will be described with reference to the drawings.
First, a schematic structure of the engine 1 is described with reference to
An engine 1 as a motor mounted to a work machine such as an agricultural machine and a construction machine includes a crankshaft 2 serving as an output shaft of the engine and a cylinder block 3 having therein a piston (not shown). On the cylinder block 3, a cylinder head 4 is mounted. On the right side surface of the cylinder head 4, an intake manifold 5 is arranged. On the left side surface of the cylinder head 4, an exhaust manifold 6 is arranged. The top surface side of the cylinder head 4 is covered by a head cover 7. The crankshaft 2 has its front and rear ends protruding from front and rear surfaces of the cylinder block 3. On the front surface side of the engine 1, a cooling fan 8 is arranged. From the front end side of the crankshaft 2, rotational power is transmitted to the cooling fan 8 through a cooling fan V-belt.
On the rear surface side of the engine 1, a flywheel housing 9 is arranged. The flywheel housing 9 accommodates therein a flywheel 10 pivotally supported at the rear end side of the crankshaft 2. The rotational power of the engine 1 is transmitted from the crankshaft 2 to operating units of the work machine through the flywheel 10. An oil pan 11 for storing an engine oil is arranged on a lower surface of the cylinder block 3. The engine oil in the oil pan 11 is supplied to lubrication parts of the engine 1 through an oil pump in the cylinder block 3, and then returns to the oil pan 11.
A fuel supply pump 13 is arranged below the intake manifold 5 on the right side surface of the cylinder block 3. Further, the engine 1 includes injectors 14 for four cylinders. Each of the injectors 14 has a fuel injection valve of electromagnetic-controlled type. By controlling the opening/closing of the fuel injection valves of the injectors 14, the high-pressure fuel in a common rail is injected from the injectors 14 to the respective cylinders of the engine 1.
On the front surface side of the cylinder block 3, a cooling water pump 15 for supplying cooling water is arranged. The rotational power of the crankshaft 2 drives the cooling water pump 15 along with the cooling fan 8, through the cooling fan V-belt. With the driving of the cooling water pump 15, the cooling water in a radiator (not shown) mounted to the work machine is supplied to the cylinder block 3 and the cylinder head 4 and cools the engine 1. Then the cooling water having contributed to the cooling of the engine 1 returns to the radiator. Above the cooling water pump 15, an alternator 16 is arranged.
The intake manifold 5 is connected to an intake throttle member 17. The fresh air (outside air) suctioned by the air cleaner is subjected to dust removal and purification in the air cleaner, and fed to the intake manifold 5 through the intake throttle member 17, and then supplied to the respective cylinders of the engine 1.
In an upper portion of the intake manifold 5, an EGR device 18 is arranged. The EGR device 18 is a device that supplies part of the exhaust gas of the engine 1 (EGR gas from the exhaust manifold 6) to the intake manifold 5, and includes an EGR pipe 21 connecting to the exhaust manifold 6 through an EGR cooler 20 and an EGR valve case 19 that communicates the intake manifold 5 to the EGR pipe 21.
A downwardly-open end portion of the EGR valve case 19 is bolt-fastened to an inlet of the intake manifold 5 protruding upward from the intake manifold 5. Further, a rightwardly-open end portion of the EGR valve case 19 is coupled to an outlet side of the EGR pipe 21. By adjusting the opening degree of the EGR valve member (not shown) in the EGR valve case 19, the amount of EGR gas supplied from the EGR pipe 21 to the intake manifold 5 is adjusted. The EGR valve member is driven by an actuator 22 attached to the EGR valve case 19.
In the intake manifold 5, the fresh air supplied from the air cleaner to the intake manifold 5 through the intake throttle member 17 is mixed with the EGR gas (part of exhaust gas from the exhaust manifold 6) supplied from the exhaust manifold 6 to the intake manifold 5 through the EGR valve case 19. As described, by recirculating part of the exhaust gas from the exhaust manifold 6 to the engine 1 through the intake manifold 5, the combustion temperature is lowered and the emission of nitrogen oxide (NOX) from the engine 1 is reduced.
The EGR pipe 21 is connected to the EGR cooler 20 and the EGR valve case 19. The EGR pipe 21 includes a first EGR pipe 21a arranged on the right side of the cylinder head 4, a second EGR pipe 21b formed in a rear end portion of the cylinder head 4, and a third EGR pipe 21c arranged on the left side of the cylinder head 4.
The first EGR pipe 21a is generally an L-shaped pipe. The first EGR pipe 21a has its inlet side coupled to an outlet side of the second EGR pipe 21b, and has its outlet side coupled to the EGR valve case 19.
The second EGR pipe 21b is formed in such a manner as to penetrate through the rear end portion of the cylinder head 4 in the left-and-right directions as shown in
The third EGR pipe 21c is formed inside the exhaust manifold 6. In other words, the third EGR pipe 21c and the exhaust manifold 6 are integrally formed. With the third EGR pipe 21c and second EGR pipe 21b integrally formed with the exhaust manifold 6 and the cylinder head 4, respectively, the space needed can be saved, and the pipes less likely receive an external impact.
As is well known, the structure of the oil cooler 24 includes a plurality of plate-like cores 240 (five cores in the present embodiment) which are connected to and spaced from one another, and the engine oil is supplied into each of the cores 240. The engine oil is cooled by heat exchanging with the cooling water around the cores 240.
Each core 240 has an oil inflow port 240a and an oil ejection port 240b. The oil inflow ports 240a of the cores 240 are supported by a first oil pipe 241 (corresponding to support member), and the oil ejection ports 240b of the cores 240 are supported by a second oil pipe 242 (corresponding to the support member). The inside of the first oil pipe 241 is in communication with the oil inflow ports 240a of the cores 240, and the inside of the second oil pipe 242 is in communication with the oil ejection ports 240b of the cores 240. This way, the engine oil passing through the first oil pipe 241 is fed from the oil inflow ports 240a to the cores 240, and the engine oil in the cores 240 is ejected to the second oil pipe 242 from the oil ejection ports 240b.
In the right side surface of the cylinder block 3, the accommodation part 25 (corresponding to accommodation space) for accommodating therein the oil cooler 24 is formed. The accommodation part 25 is a part of the cooling water passage, and the cooling water in the accommodation part 25 is circulated by the cooling water pump 15. By having the cooling water passing the accommodation part 25, the engine oil in the oil cooler 24 (cores 240) accommodated in the accommodation part 25 is cooled.
A side of the accommodation part 25 is open, and a side plate 26 for closing the opening is fixed to the opening. As shown in
On a surface of the side plate 26 facing the oil cooler 24, a supply port (not shown) and a discharge port (not shown) are provided. The supply port is connected to the first oil pipe 241 to supply engine oil to the oil cooler 24. The discharge port is connected to the second oil pipe 242 to discharge the engine oil ejected from the oil cooler 24.
The cooling water inflow port 25a is connected to a cooling water inflow passage 27 which guides the cooling water ejected from the cooling water pump 15. The cooling water inflow passage 27 includes an inclined portion 27a closer to the accommodation part 25, and a straight portion 27b extended from the inclined portion 27a towards the cooling water pump 15. The inclined portion 27a is inclined downward and connects to the cooling water inflow port 25a. As a result, the cooling water passing through the inclined portion 27a forms a downward flow, and the downward flow of the cooling water flows into the accommodation part 25 from the cooling water inlet 25a. As a result, the cooling water can be supplied to the entire oil cooler 24 without having the cooling water colliding with the second oil pipe 242.
The cooling water inflow passage 27 includes an upper protrusion 271 protruding downward from an upper passage wall, and a lower protrusion 272 protruding upward from a lower passage wall. The upper protrusion 271 protrudes downward to a level lower than the upper passage wall of the straight portion 27b. The lower protrusion 272 protrudes upward to a level higher than a lower end portion of the cooling water inflow port 25a. The upper protrusion 271 is arranged closer to the oil cooler 24 (closer to the accommodation part 25) than the lower protrusion 272. With the upper protrusion 271 and the lower protrusion 272 arranged as described above, the inclined portion 27a inclined downward is formed. With this structure, the cooling water flowing in the cooling water inflow passage 27 collides with the upper protrusion 271 and flows downward. Therefore, the cooling water does not collide with the second oil pipe 242.
Further, a protrusion 25d protruding upward is arranged on the bottom surface of the accommodation part 25. The protrusion 25d is arranged in a middle portion of the bottom surface of the accommodation part 25 relative to the front-and-rear direction. More specifically, the protrusion 25d is arranged between the first oil pipe 241 and the second oil pipe 242. With the protrusion 25d, the cooling water flowing in the vicinity of the bottom surface of the accommodation part 25 collides with the protrusion 25d, thus increasing the rate of cooling water flowing in the middle portion of the oil cooler 24 relative to the front-and-rear direction. Therefore, the cooling efficiency can be improved. Further, since the protrusion 25d can be formed at the same time when casting the cylinder block 3, no additional cost for machining is necessary. By modifying the shape and the position of the protrusion 25d according to the flow of the cooling water, the flow of the cooling water can be optimized without a need for modification of the shape of the oil cooler 24.
(1) As shown in
With the wax pellet 28 between the oil cooler 24 and the side wall 25c of the accommodation part 25, the wax pellet 28 is shrunk while the temperature of the lubrication oil is low, such as in an occasion of starting the engine. During this state, the cooling water flows into the gap between the wax pellet 28 and the side wall 25c of the accommodation part 25, and the amount of cooling water flowing to the cores 240 is reduced. Therefore, the heat exchange efficiency of the oil cooler 24 is lowered. This enables quick warm up of the engine 1.
On the other hand, when the temperature of the lubrication oil is high, the wax pellet 28 expands and fills the gap between the wax pellet 28 and the side wall 25c of the accommodation part 25. This increases the amount of cooling water flowing between the cores 240, and sufficient heat exchanging efficiency of the oil cooler 24 can be achieved.
(2) As shown in
The cooling water pump 15 is structured by a centrifugal pump, and the cooling water ejected from the cooling water pump 15 may form a strong swirl flow inside the cooling water inflow passage 27. When such a strong swirl flow occurs, the cooling water easily flows around the oil cooler 24 due to the centrifugal force, which results in a decrease in the amount of cooling water to the cores 240 and a drop in the heat exchanging efficiency of the oil cooler 24. With the current plate 29, however, the swirl flow can be suppressed, and the amount of cooling water flowing between the cores 240 increases. Therefore, the heat exchanging efficiency of the oil cooler 24 is improved.
An embodiment of the present invention has been described with reference to the drawings. It however should be considered that specific configurations of the present invention are not limited to this embodiment. The scope of this invention is indicated by the range of patent claims as well as the description of the enforcement form described above, as well as the range of patent claims and even meaning and all changes within the range.
Number | Date | Country | Kind |
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JP2017-240460 | Dec 2017 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2018/043388 | 11/26/2018 | WO |
Publishing Document | Publishing Date | Country | Kind |
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WO2019/116867 | 6/20/2019 | WO | A |
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20030148679 | Matsuda | Aug 2003 | A1 |
20150144312 | Ooi | May 2015 | A1 |
20160195000 | Nakashima | Jul 2016 | A1 |
20170205153 | Hermida Domínguez | Jul 2017 | A1 |
20170314398 | Slavens | Nov 2017 | A1 |
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International Search Report for PCT Patent App No. PCT/JP2018/043388 (dated Jan. 29, 2019). |
Number | Date | Country | |
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20210293176 A1 | Sep 2021 | US |