Internal combustion engine

Abstract

An internal combustion engine (1) includes a cylinder head (2), a cylinder block (3), an oil pan (4) attached to a lower part of the cylinder block 3, and a front cover 6 that covers a front surface of an internal combustion engine body (5). The cylinder head (2) and the cylinder block (3) constitute the internal combustion engine body (5). An internal combustion engine (1) has an oil pump (7) attached to an oil pan (4), and an oil cooler (8) attached to the outer side of an end wall (10) on one end side of the oil pan (4). Even when the total length of the internal combustion engine body (5) along a cylinder row direction is short, the overall length of the internal combustion engine (1) along the cylinder row direction can be kept from becoming long while a layout configuration for attaching the oil cooler (8) to the internal combustion engine (1) is established.

Description

internal combustion engine

[0001] The present invention relates to an internal combustion engine having an oil pump and an oil cooler.

[0002] For example, Patent Document 1 discloses an engine (internal combustion engine) in which a water pump is installed on the side of the engine, and a cooling water passage is formed between the water pump and an oil cooler without using any additional hoses, etc., and the oil cooler is fixed below the underside of the crankcase, which is exposed by a recessed inward recess on the side of the oil pan.

[0003] However, even if the engine of Patent Document 1 is made longer in stroke or the number of cylinders is reduced, there is a risk that the overall length along the axial direction of the crankshaft cannot be shortened.

[0004] That is, from the viewpoint of layout, there is room for further improvement in the position where the oil cooler is disposed in the internal combustion engine.

[0005] Japanese Unexamined Patent Publication No. 7-174022

[0006] The internal combustion engine has an oil pan attached to the lower part of the cylinder block, and an oil cooler attached to an end wall on one end side of the oil pan in the axial direction of the crankshaft.

[0007] The internal combustion engine of the present invention can achieve a layout configuration in which an oil cooler is attached to the internal combustion engine, while preventing the overall length along the cylinder row direction from becoming long.

[0008] 1 is a schematic diagram of an internal combustion engine according to the present invention, the schematic diagram being viewed from one side in the width direction of the internal combustion engine; 2 is a schematic diagram of an internal combustion engine according to the present invention, the schematic diagram being viewed from one end side in the cylinder row direction; 3 is a schematic diagram of an internal combustion engine of a comparative example, the schematic diagram being viewed from one side in the width direction of the internal combustion engine;

[0009] An embodiment of the present invention will be described in detail below with reference to the drawings. In each drawing, the X-axis represents an axis along the longitudinal direction of the internal combustion engine 1 (an axis parallel to the central axis of the crankshaft of the internal combustion engine 1), the Y-axis represents an axis along the left-right direction of the internal combustion engine 1 (the width direction of the internal combustion engine), and the Z-axis represents an axis along the vertical direction of the internal combustion engine 1 (an axis parallel to the cylinder axis L of the internal combustion engine 1). In other words, the X-axis is an axis along the cylinder row direction (the axial direction of the crankshaft) of the internal combustion engine 1 or the internal combustion engine body 5 (described later). The Y-axis is an axis along the width direction of the internal combustion engine 1 or the internal combustion engine body 5.

[0010] 1 and 2 are explanatory diagrams that schematically show the overall configuration of an internal combustion engine 1 according to the present invention. Fig. 1 is an explanatory diagram that schematically shows the internal combustion engine 1 as viewed from one side in the width direction of the engine, i.e., as viewed from one side in the Y-axis direction. Fig. 2 is an explanatory diagram that schematically shows the internal combustion engine 1 as viewed from one end in the cylinder row direction, i.e., as viewed from one end in the X-axis direction.

[0011] The internal combustion engine 1 is, for example, an in-line three-cylinder internal combustion engine and is mounted on a vehicle such as an automobile. The internal combustion engine 1 has a short overall length along the axial direction of the crankshaft, for example, due to a small number of cylinders or a long piston stroke.

[0012] The internal combustion engine 1 has a cylinder head 2, a cylinder block 3 attached to the lower part of the cylinder head 2, an oil pan 4 attached to the lower part of the cylinder block 3, and a front cover 6 that covers the front of the internal combustion engine body 5 and the oil pan 4. The internal combustion engine body 5 is made up of the cylinder head 2 and the cylinder block 3. Here, the front of the internal combustion engine body 5 refers to the surface on one end side of the internal combustion engine body 5 (internal combustion engine 1) in the X-axis direction, in front of the internal combustion engine 1, where accessories such as an alternator and pulleys are generally provided.

[0013] The cylinder head 2 is a casting made of a metal material such as an aluminum alloy, and is formed with an intake port (not shown) for supplying intake air to a combustion chamber (not shown), and an exhaust port (not shown) for discharging exhaust gas from the combustion chamber (not shown).

[0014] The cylinder block 3 is a casting made of a metal material such as an aluminum alloy, and has cylinders (not shown) formed therein, the number of which corresponds to the number of cylinders.

[0015] The oil pan 4 is made of a metal material such as an aluminum alloy or a resin material such as a hard synthetic resin, and together with the cylinder block 3 forms a crankcase (not shown) that houses the crankshaft (not shown), and also stores oil for lubrication.

[0016] The front cover 6 is made of a synthetic resin material such as polyamide or a metal material such as aluminum alloy, and is attached liquid-tight to the internal combustion engine body 5 and the oil pan 4 so as to cover the front surfaces of the internal combustion engine body 5 and the oil pan 4. More specifically, the front cover 6 is attached to the front surface of the cylinder block 3, the front surface of the cylinder head 2, and the front surface of the oil pan 4 with bolts (not shown). In other words, the front cover 6 is attached to the internal combustion engine body 5 and the oil pan 4 so as to cover an end surface 5a on one end side of the internal combustion engine body 5 in the cylinder row direction. As is the case with many general internal combustion engines, the front cover 6 is constructed with the minimum necessary thickness so as not to increase the mass of the internal combustion engine 1, and has relatively lower strength (rigidity) than, for example, the oil pan 4.

[0017] The front cover 6 has a shallow dish shape, and forms a space that communicates with the oil storage space in the oil pan 4 between itself and the front surface of the internal combustion engine body 5, which is an end face 5a at one end in the cylinder row direction of the internal combustion engine body 5. The lower part of this space, i.e., the lower part inside the front cover 6, also serves as an oil storage space for storing oil.

[0018] The internal combustion engine 1 is equipped with an oil pump 7, an oil cooler 8, and an air conditioning compressor 9.

[0019] The oil pump 7 is driven by, for example, the internal combustion engine 1, attached to the oil pan 4, and provided in the oil storage space. In particular, it is located forward in the cylinder row direction of the internal combustion engine 1 so that it can be easily driven by the internal combustion engine 1, like other accessories. For example, the oil pump 7 is attached to an end wall 10 on one end side of the oil pan 4. In this case, the oil pump 7 is located between the front cover 6 and the end wall 10 on one end side of the oil pan 4 in the cylinder row direction, and is covered by the front cover 6. The oil pump 7 is located in the space inside the front cover 6.

[0020] The oil cooler 8 is attached to the outside of an end wall 10 on one end of the oil pan 4 in the cylinder row direction of the internal combustion engine 1, i.e., on a surface (part of the front surface of the oil pan 4) that is exposed to the outside and in front of the oil pan 4, and is attached as close as possible to the oil pump 7, which is also provided toward the front of the internal combustion engine 1. For example, the oil pump 7 and the oil cooler 8 are attached so as to overlap in the longitudinal direction of the internal combustion engine 1 and be adjacent to each other in the width (left-right) direction of the internal combustion engine 1. The oil cooler 8 is located outside the front cover 6 and is not covered by the front cover 6. In other words, the front cover 6 is configured so that the portion of the end wall 10 on one end of the oil pan 4 in the cylinder row direction where the oil cooler 8 is attached is not covered, and may be shaped, for example, so that a portion on the lower side is cut out. In a plan view of the internal combustion engine 1, the front cover 6 overlaps at least a portion of the oil cooler 8, in other words, it covers the front surface (end surface 5a) of the internal combustion engine body 5 above the oil cooler 8 so that at least a portion of the oil cooler 8 is hidden behind the front cover when the internal combustion engine 1 is viewed from above. Therefore, by arranging the oil cooler 8 on the front surface in front of the internal combustion engine 1 while leaving the space above the oil cooler as the space inside the front cover, it is possible to ensure the capacity required for the space inside the front cover, or the space for arranging the components covered by the front cover.

[0021] The oil cooler 8 is connected to the oil pump 7 via an inter-pump-cooler oil passage 11 so as to be downstream of the oil pump 7 in the oil flow direction.

[0022] One end of an inter-pump-cooler oil passage 11 connecting the oil pump 7 and the oil cooler 8 is connected to an oil discharge port of the oil pump 7 and the other end is connected to an oil inlet port of the oil cooler 8. The inter-pump-cooler oil passage 11 is formed in an end wall 10 on one end side of the oil pan 4. The other end of the oil passage 11 opens to the front surface of the oil pan 4 on which the oil cooler 8 is attached, and communicates with the oil inlet port of the oil cooler 8 attached to the oil pan 4.

[0023] The compressor 9 is driven by, for example, the internal combustion engine 1 and is attached to one side of the internal combustion engine 1, straddling the cylinder head 2 and the oil pan 4. The compressor 9 compresses the refrigerant gas of an air conditioner that regulates the temperature inside the vehicle. Because the compressor 9 is attached to the side of the oil pan 4, the remaining free space is narrowed because it protrudes downward.

[0024] Figure 3 shows an internal combustion engine 21 of a comparative example. In Figure 3, the same components as those in the above-described embodiment are denoted by the same reference numerals, and duplicated explanations will be omitted. The internal combustion engine 21 of the comparative example differs from the internal combustion engine 1 of the above-described embodiment in that the oil cooler 8 is attached to one side of the oil pan 4.

[0025] In the internal combustion engine 21 of the comparative example, the compressor 9 and oil cooler 8 are attached side by side to one side of the internal combustion engine 21. Here, if the overall length along the cylinder row direction is long like the internal combustion engine 21 of the comparative example, the compressor 9 can be attached to the internal combustion engine body 5 at a relatively high position so as not to interfere with the intake manifold 22 attached to the cylinder head 2. Therefore, the oil cooler 8 can be disposed below the compressor 9 and attached to one side of the oil pan 4.

[0026] However, in the case of the internal combustion engine 21 of the comparative example, if an attempt is made to shorten the overall length along the cylinder row direction by downsizing the engine by lengthening the piston stroke or reducing the number of cylinders, the space on both sides of the intake manifold 22 will become narrower, and the compressor 9 will have to be moved downward, for example, which may mean that it will no longer be possible to ensure space to attach the oil cooler 8 on one side of the internal combustion engine 21 as before (it will not be possible to overlap the oil cooler 8 and compressor 9 with most of their space in the cylinder row direction).

[0027] In this case, it is conceivable to mount the oil cooler 8 and the compressor 9 side by side in the cylinder row direction of the internal combustion engine 21, but one side of the internal combustion engine 21 (the internal combustion engine body 5 or the oil pan 4) would need to be long enough to mount the oil cooler 8 and the compressor 9 side by side in the cylinder row direction, which could make it impossible to sufficiently shorten the overall length of the internal combustion engine 21 along the cylinder row direction. Also, in order to arrange the oil cooler 8 and the compressor 9 side by side while shortening the overall length of the internal combustion engine, it is conceivable to mount the oil cooler 8 on a side surface of the front cover 6 (a side surface in the left-right width direction of the internal combustion engine), but this would require measures to increase the strength of the front cover 6, which has low strength, such as increasing its thickness, which would increase the mass of the internal combustion engine.

[0028] In contrast, the oil cooler 8 in the internal combustion engine 1 of the above-described embodiment is attached not to one side surface of the internal combustion engine 1 but to the front of the oil pan 4 in the cylinder alignment direction of the internal combustion engine 1, for example, to the end wall 10 on one end side. Therefore, one side surface of the internal combustion engine 1 (internal combustion engine body 5 and oil pan 4) does not need to be long enough to attach the oil cooler 8 and the compressor 9 side by side in the cylinder alignment direction. Even if the overall length of the internal combustion engine body 5 in the cylinder alignment direction is shortened due to downsizing, a layout configuration in which the oil cooler 8 is attached to the internal combustion engine 1 can be established. When the oil cooler and the compressor need to be attached side by side in the cylinder alignment direction of the internal combustion engine, even if the oil cooler is fixed below the underside of the crankcase as in the prior art (Patent Document 1), the length of the crankcase in the cylinder alignment direction needs to be long enough to attach the oil cooler and the compressor side by side in the cylinder alignment direction, which may make it difficult to shorten the overall length of the internal combustion engine in the cylinder alignment direction. However, according to the internal combustion engine 1 of the embodiment, even if the oil cooler 8 and the compressor 9 cannot be overlapped in the cylinder row direction for the most part, the overall length of the internal combustion engine 1 along the cylinder row direction can be shortened.

[0029] Furthermore, since the oil pump 7 is provided in the oil storage space surrounded by the oil pan 4 and the lower part of the front cover 6, and furthermore, is provided towards the front in the direction of the cylinder row of the internal combustion engine 1, the length (passage length) of the pump-to-cooler oil passage 11 connecting the oil pump 7 and the oil cooler 8 can be shortened in the internal combustion engine 1.

[0030] Furthermore, since the oil cooler 8 is disposed in the internal combustion engine 1 so as not to protrude to the side of the internal combustion engine 1, the oil cooler 8 can be prevented from interfering with other components.

[0031] Furthermore, in the internal combustion engine 1, the oil cooler 8 is attached to the oil pan 4, which has a high structural rigidity, rather than to the front cover 6, so that noise radiated by oil pressure and vibration of the oil cooler 8 can be suppressed.

[0032] In the internal combustion engine 1, an inter-pump-cooler oil passage 11 that connects the oil pump 7 and the oil cooler 8 is formed in an end wall 10 on one end side of the oil pan 4.

[0033] Therefore, in the internal combustion engine 1, oil can be transferred between the oil pump 7 and the oil cooler 8 only through the inter-pump-cooler oil passage 11 formed in the oil pan 4, so the inter-pump-cooler oil passage 11 connecting the oil pump 7 and the oil cooler 8 is relatively short and does not require a complex structure that requires a sealing structure along the way, thereby reducing costs and improving the reliability and durability of the oil passage between the oil pump 7 and the oil cooler 8.

[0034] In the internal combustion engine 1, the oil cooler 8 is attached to the end wall 10 on one end side of the oil pan 4, so even if the compressor 9 is attached to one side of the internal combustion engine body 5, a compact layout can be achieved as a whole.

[0035] The present invention is more effective in an internal combustion engine having a short overall length along the axial direction of the crankshaft (direction of the cylinder rows), and for example, this layout is more effective in an in-line three-cylinder internal combustion engine than in an in-line four-cylinder engine.

Claims

1. An internal combustion engine having an oil pan attached to the lower part of the internal combustion engine body, and an oil cooler attached to an end wall on one end side of the oil pan in the axial direction of the crankshaft.

2. An internal combustion engine according to claim 1, wherein said oil cooler is attached to the outside of said oil pan.

3. An internal combustion engine according to claim 2, wherein the one end is at the front of the internal combustion engine, and the internal combustion engine has an oil pump attached to the oil pan 4 at the front of the internal combustion engine.

4. An internal combustion engine according to claim 3, wherein said oil pump is attached to an end wall on one end side of said oil pan.

5. An internal combustion engine according to claim 3, wherein an oil passage connecting said oil pump and said oil cooler is formed in an end wall on one end side of said oil pan.

6. An internal combustion engine according to claim 3, further comprising a front cover that covers one end of the internal combustion engine body and the oil pan in the direction of cylinder alignment, the oil cooler being located outside the front cover, and the oil pump being located in the space inside the front cover.

7. An internal combustion engine according to claim 6, wherein the front cover covers the front surface of the internal combustion engine body above the oil cooler.

8. An internal combustion engine according to claim 2, wherein the air conditioning compressor is attached to one side of the internal combustion engine.

9. An internal combustion engine according to claim 3, wherein the number of cylinders is three.

10. An internal combustion engine as set forth in claim 7, wherein the front cover has a cutout on the lower side so as not to cover the portion of the end wall on one end side of the oil pan in the cylinder row direction where the oil cooler is attached.

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