Monoblock engine

Abstract

To provide a technology for allowing a proper amount of cooling water to flow to a block-side cooling water jacket and a head-side cooling water jacket, in a monoblock-type engine in which a cylinder head and a cylinder block are integrally casted.SOLUTION: A block-side cooling water jacket 5 and a head-side cooling water jacket 19 are directly communicated to each other. A cooling water inlet 23 long in a longitudinal direction in association with two cylinders 6, is formed on a region at an upper end portion of the block-side cooling water jacket 5 or a lower end portion of the head-side cooling water jacket 19 and close to a front end or a rear end of a cylinder row. Cutouts 25, 27 opened at lower parts, are formed on a front end and a rear end of the block-side cooling water jacket 5. The cooling water vertically flows toward a rear end of the cylinder row while laterally flowing to cross the head-side cooling water jacket 19 and is also branched to an upper portion of the block-side cooling water jacket 5, so that an upper portion of the cylinders 6 can be surely cooled.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a monoblock engine in which a cylinder head and a cylinder block are integrated into a main body block, and is characterized in particular by the manner in which cooling water flows.

[0002] In a reciprocating engine such as a gasoline engine or a diesel engine, a cooling water jacket is formed around the cylinder to cool the cylinder and the piston, and a cooling water jacket is also formed inside the cylinder head.

[0003] There are several types of engine cooling methods, but in the case of a typical engine in which the cylinder block and cylinder head are manufactured as separate components, a communication hole is drilled in the gasket interposed between the cylinder head and the cylinder block, and water is often passed from the cooling water jacket of the cylinder block to the cooling water jacket of the cylinder head through this communication hole and a communication hole (water leg) formed in the cylinder head.

[0004] On the other hand, Patent Document 1 discloses a cooling method for a monoblock engine in which a block-side cooling water jacket is provided on the cylinder block, while a head-side cooling water jacket is provided on the cylinder head 2, and a plurality of communication holes are formed in the cylinder head, arranged in a circumferential direction, to spray cooling water from the block-side cooling water jacket to the head-side cooling water jacket. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Microfilm of Utility Model Publication No. 63-171644 Summary of the Invention [Problem to be solved by the invention]

[0006] Although Patent Document 1 can be said to apply the water passage structure of the separated block type directly to a monoblock, the cooling water flows into the head side cooling water jacket while circling the block side cooling water jacket, which causes problems such as increased flow resistance and overcooling of the cylinders.In addition, when casting the main body block, the communication holes are made of sand cores, but the cores become thin bridge-like at the communication holes, which increases the risk of breakage or damage, and there are concerns that this will increase the manufacturing effort and reduce the yield.

[0007] The present invention has been made against this background, and aims to disclose a technology for a monoblock engine that can adequately cool the cylinder block and cylinder head without causing manufacturing problems. [Means for solving the problem]

[0008] The monoblock engine of the present invention is "A cylinder block integrated with a cylinder head is formed with a group of cylinder bores opening downward and a block-side cooling water jacket surrounding the group of cylinder bores, The cylinder head is formed with a head-side cooling water jacket that is in direct communication with the block-side cooling water jacket. This is the basic configuration.

[0009] In the above basic configuration, "A cooling water inlet that is long in the cylinder row direction is provided at the upper end of the block-side cooling water jacket near one end of the cylinder row, or at the lower end of the head-side cooling water jacket near one end of the cylinder row, straddling the first and second cylinders as seen from one end of the cylinder row, And, one end of the cylinder row of the block side cooling water jacket On one end and on the other end, they are located on the center line of the cylinder row. Opened downwards No. 1 Notch and a second notch that opens downward at a location circumferentially spaced from the first notch. It has been done. It has the following characteristics:

[0010] The present invention can be developed in various ways. For example, in claim 2, " A third notch is formed on each of the head side cooling water jacket at one end and the other end of the cylinder row, the third notch being open upward and symmetrical to the first notch. " The structure is as follows.

[0011] The present invention also includes a state in which the cooling water inlet straddles both the upper end of the block-side cooling water jacket and the lower end of the head-side cooling water jacket. Ma In the present invention, the cooling water inlet can be disposed on either the intake side or the exhaust side, but is preferably disposed on the intake side. Effect of the Invention

[0012] In the present invention, the cooling water inlet of Since the cooling water inlet is provided at the upper end of the block side cooling water jacket or the lower end of the head side cooling water jacket, it is possible to prevent the cylinders from being overcooled. Also, since the cooling water inlet is long in the cylinder row direction, even if the cooling water inlet is provided at the upper end of the block side cooling water jacket or the lower end of the head side cooling water jacket, the cooling water can be reliably sent to the upper part of the block side cooling water jacket, and the upper part of the cylinder can be reliably cooled. Therefore, it has an excellent knocking prevention function.

[0013] In addition, since the cooling water inlet is provided near one end of the cylinder row, the cooling water tends to flow vertically through the block-side cooling water jacket and the head-side cooling water jacket from one end of the cylinder row to the other end, thereby making the flow of cooling water smoother.

[0014] While it is theoretically possible to locate the cooling water inlet at one end of the cylinder row, due to relationships with other components and restrictions on forming the water passages, the cooling water inlet must often be located on the side of the intake or exhaust side. In this invention, the cooling water inlet is located near one end of the cylinder row for this reason. By locating the cooling water near one end of the cylinder row in this manner, it is possible to prevent too much cooling water from flowing in the direction of one end of the block-side cooling water jacket and to allow the cooling water to flow evenly through the block-side cooling water jacket and the head-side cooling water jacket.

[0015] And because the block-side cooling water jacket and the head-side cooling water jacket communicate directly and not through a communication hole, there is no need to form a bridge-like portion during casting, and because the cooling water inlet is long in the cylinder row direction, the core can be manufactured easily, and because the notches open downward, the core for forming the notches is also easy to manufacture. Thus, while the present invention can optimize the flow of cooling water as described above, it also makes it possible to manufacture (cast) a monoblock-type main body block easily and with high precision without any particular difficulty.

[0016] Block side cooling water jacket for cylinder row On both sides Forming a notch As I was saying Since the flow around the block-side cooling water jacket is interrupted, the cooling water is prevented from flowing excessively into the block-side cooling water jacket, and excessive cooling of the cylinders can be prevented. The flow of the cooling water can be optimized by adjusting the number and depth of the notches. In addition, since the second notch is also formed, the cooling water is prevented from entering the cooling water jacket on the block side too much, improving the flow straightening function. [Brief description of the drawings]

[0017] [Figure 1] FIG. 4 is a bottom view mainly showing the shape of a cooling water jacket in the embodiment. [Diagram 2] FIG. 2 is a perspective view of a lower-stage head-side cooling water jacket and a block-side cooling water jacket as viewed from above. [Diagram 3] FIG. 4 is a perspective view mainly showing the block-side cooling water jacket from below. [Figure 4] FIG. 4 is a longitudinal sectional front view seen from the IV-IV direction in FIG. [Diagram 5] FIG. 5 is a schematic cross-sectional view taken along line V-V of FIG. 4. [Figure 6] FIG. 2 is a side view of the lower-stage head side cooling water jacket and the block side cooling water jacket as viewed from the exhaust side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Next, an embodiment of the present invention will be described with reference to the drawings. This embodiment is applied to a three-cylinder engine for a vehicle (automobile). In the following, the terms front-rear and left-right are used to specify directions, but the front-rear direction is the crankshaft direction, and the left-right direction is the direction perpendicular to the crankshaft and the cylinder bore axis. Regarding front and rear, the side where the timing chain is located is the front, and the side where the transmission is located is the rear.

[0019] (1) Structure Description First, the basic structure of the engine will be described with reference to Figure 4. The engine has, as its basic element, a monoblock-type main body block 3 in which a cylinder block 1 and a cylinder head 2 are integrated, and a crankcase (not shown) is fixed to the underside of the cylinder block 1 by a group of bolts.

[0020] The cylinder block 1 is formed with a group of cylinder bores 4 that open downward and a block-side cooling water jacket 5 that surrounds the group of cylinder bores 4. The space between the cylinder bores 4 and the block-side cooling water jacket 5 forms a cylinder 6. Naturally, the upper end of the cylinder 6 is integrally connected to the cylinder head 2.

[0021] The block-side cooling water jacket 5 is roughly in the shape of a loop surrounding the group of cylinder bores 4, with an inter-bore section 7 between adjacent cylinder bores 4, and the block-side cooling water jacket 5 extends toward the inter-bore section 7 (see also Figure 5).

[0022] A recess (combustion chamber) 8 that opens toward the cylinder bore 4 is formed in the cylinder head 2, and a pair of intake ports 9 and exhaust ports 10, one at the front and one at the rear, open from both the left and right sides of the recess 8. The end of the intake port 9 is opened and closed by an intake valve 11, and the beginning of the intake port 9 is opened and closed by an exhaust valve 12. The valves 11, 12 are urged in the closing direction by a spring 13.

[0023] A pair of front and rear intake ports 9 are opened separately on the intake side (not shown) of the cylinder head 2, and an intake manifold is fixed to the intake side of the cylinder head 2. On the other hand, each pair of exhaust ports 9 communicates with a collecting passage 14 shown in FIG. 6, and the collecting passage 14 opens from one exhaust outlet 15 on the exhaust side of the cylinder head 2. A catalyst case or an exhaust turbocharger is connected to the exhaust outlet 15. An electrode of an ignition plug 16 is exposed in the recess 8. It goes without saying that a piston 17 is slidably fitted in the cylinder bore 4.

[0024] (2).Cooling structure As shown in Fig. 4, the cylinder head 2 is formed with a lower-stage head-side cooling water jacket 19. As shown in Fig. 6, the cylinder head 2 is also formed with an upper-stage head-side cooling water jacket 20 located above the group of exhaust ports 9 (note that the hatching in Fig. 6 is applied to clarify the shapes of the exhaust passages and the intake ports 8, and is not an indication of a cross section). The lower-stage head-side cooling water jacket 19 has an intake side portion 19a, a center portion (above the bore) 19b, and an exhaust side portion 19c that are connected in series. However, the boundaries between the center portion 19b and the intake side portion 19a and between the center portion 19b and the exhaust side portion 19c are not necessarily clear.

[0025] 2 shows the lower-stage head side cooling water jacket 19. In addition, in Fig. 2, a plurality of cylindrical portions 21 protrude from the exhaust side portion of the lower-stage head side cooling water jacket 19, and these cylindrical portions 21 are connected to the upper-stage head side cooling water jacket 20. That is, the cooling water flows from the lower-stage head side cooling water jacket 19 to the upper-stage head side cooling water jacket 20 through the group of cylindrical portions 21 on the exhaust side, flows vertically from front to back through the upper-stage head side cooling water jacket 20, and is discharged from a cooling water outlet 22 shown in Fig. 6. Therefore, in this embodiment, the upper-stage head side cooling water jacket 20 is disposed only on the exhaust side, but it is possible to form it so that it extends to the intake side as well. The cooling water outlet 22 mainly communicates with the upper-stage head side cooling water jacket 20, but also partially overlaps with the lower-stage head side cooling water jacket 19. Note that the hatching in Fig. 2 is intended to clarify the shape of the intake port 8, and is not an indication of a cross section.

[0026] As shown in Fig. 4, the intake side portion of the block side cooling water jacket 5 is integrally connected to the intake side portion 19a of the lower-stage head side cooling water jacket 19. On the other hand, the exhaust side portion of the block side cooling water jacket 5 is integrally connected to the exhaust side portion 19c and the center portion 19b of the lower-stage head side cooling water jacket 19. In Fig. 4, the intake side portion 19a and the center portion 19b of the lower-stage head side cooling water jacket 19 are separate, but the two are directly connected at, for example, the inter-bore portion 7.

[0027] 2, for example, a cooling water inlet 23 is connected to a front portion of the intake side portion 19a of the head side cooling water jacket 19. The cooling water inlet 23 is formed longitudinally in the front-to-rear direction so as to span the first and second cylinders 6 from the front. Cooling water is pressure-fed to the cooling water inlet 23 from a water pump (not shown) via a water supply passage 24. Note that the passage 24 has a stepped crank shape, and cooling water is supplied to the cooling water inlet 23 from the front, but this is due to the positional relationship with the water pump, and a configuration in which cooling water is supplied to the cooling water inlet 23 from just the side can also be used.

[0028] 1 and 3, the cooling water inlet 23 has an outward protrusion 23a, but this is formed to facilitate casting and is not related to the flow of cooling water. At the product stage, the protrusion 23a is closed with a plug.

[0029] In this embodiment, the intake side portion 19a of the head side cooling water jacket 19 and the upper end of the block side cooling water jacket 5 are directly connected to each other, but it is also possible to consider that the lower end of the cooling water inlet 23 hangs over the upper end of the block side cooling water jacket 5. Therefore, in this embodiment, it is also possible to understand that the cooling water inlet 23 is connected to the upper end of the block side cooling water jacket 5. Alternatively, it is also possible to consider that the cooling water inlet 23 is connected to both the lower end of the head side cooling water jacket 19 and the upper end of the block side cooling water jacket 5, straddling each other.

[0030] The configurations of the block side cooling water jacket 5 and the lower head side cooling water jacket 17 are shown in Figs. 1 to 3 and Figs. 5 and 6. As described above, the block side cooling water jacket 5 is basically in the form of a loop surrounding the cylinder row. As shown in Figs. 1 and 3, Located at the vertical center line that divides the cylinder row in half when viewed from the cylinder bore axial direction The front end (one end) is the front No. 1 The rear end (other end) is the rear No. 1 It is separated by a notch 26 .

[0031] In this case, as can be seen from FIGS. 2 and 3, the center portion 19b of the lower head side cooling water jacket 19 also has upwardly extending notches 25 and 26 symmetrical to the notches 25 and 26 of the block side cooling water jacket 5. Third notch Therefore, the center portion 19b of the lower-stage head side cooling water jacket 19 is thin at the locations of the notches 25 and 26 (the wall thickness is thick).

[0032] In addition, in Fig. 1, the hatching that slopes downward to the right indicates the block side cooling water jacket 5 and the cooling water inlet 23, and the hatching that slopes upward to the right indicates the lower head side cooling water jacket 19. Also, the hatching in Fig. 3 is intended to clearly show the shape of the intake port 9, and is not a representation of a cross section.

[0033] As shown in Figures 1 and 3, the block side cooling water jacket 5 surrounding the first cylinder 6 from the front is fitted with a front part at a position slightly moved from the front end to the exhaust side. SecondOn the other hand, the block side cooling water jacket 5 surrounding the third cylinder 6 has a rear end at a position slightly moved from the rear end to the intake side. Second As can be seen from FIG. No. 1 Notch 25 and front Second The notch 27 is covered by the center portion 19b of the lower-stage head-side cooling water jacket 19. No. 1 Notch 26 and rear Second The same applies to the notch 28. Since the notches 25 to 28 become solid portions, they can also be called boss portions that divide the cooling water jacket 5 on the block side.

[0034] These notches 25-28 extend over the entire height of the block side cooling water jacket 5, but it is also possible to cut out only the upper end. In other words, the block side cooling water jacket 5 can be formed so that only the upper end is connected in a loop. In addition, reference numeral 29 in Fig. 1 indicates a portion where an ignition hole is disposed, and reference numeral 30 indicates a portion where a valve is disposed. Reference numeral 31 in Figs. 1 and 2 indicates a portion for an oil drop hole.

[0035] (3) Summary In the above configuration, the cooling water flows into the lower head side cooling water jacket 19 and the block side cooling water jacket 5 from the cooling water inlet 23. However, since the cooling water inlet 20 is connected to the lower end of the lower head side cooling water jacket 19 (or the upper end of the block side cooling water jacket 5), it is possible to prevent the cylinder 6 from being overcooled and contribute to early heating of the main body block 3 and the cooling water (it can also contribute to reducing the sliding resistance of the piston by early heating of the oil).

[0036] On the other hand, the cooling water flows into the upper end of the block-side cooling water jacket 5 without fail, so that the upper part of the cylinder 6 can be cooled and an excessive temperature rise can be prevented. This makes it possible to prevent or significantly suppress knocking caused by a rise in the temperature of the intake air.

[0037] In addition, because the cooling water inlet 23 is disposed toward the front end of the cylinder head 2, the cooling water flows laterally from the intake side to the exhaust side in the lower-stage head side cooling water jacket 19, while also flowing vertically from front to back, and is smoothly guided to the cooling water outlet 22. In this case, because the cooling water inlet 23 is long in the front-to-rear direction so as to straddle the first and second cylinders 6 on the intake side, the cooling water is sent to the lower-stage head side cooling water jacket 19 so as to be diffused over a wide range. This ensures that the cooling water flows laterally across the lower-stage head side cooling water jacket 19.

[0038] In addition, since the cooling water inlet 23 discharges toward the inter-bore portion 7 between the first cylinder 6 and the second cylinder 6, the inter-bore portion 7 functions as a buffer portion, and it is possible to ensure that the cooling water flows not only backward but also forward. Therefore, the front end portion of the first cylinder 6 is also cooled appropriately. In addition, if the cooling water inlet 23 is long in the front-rear direction, the robustness of the core for casting is increased, which is advantageous in terms of manufacturing.

[0039] If the block-side cooling water jacket 5 has a simple loop structure, the cooling water may flow over the entire height. No. 1 Notch 25 and rear No. 1 When the notches 26 are formed, the flow of cooling water is blocked by the solid portions of the notches 25, 26, so that the flow of cooling water is formed only at the upper end of the block side cooling water jacket 5, and the flow of cooling water can be eliminated in the portion of the block side cooling water jacket 5 excluding the upper end. This enhances the heat retention effect of the cooling water and prevents excessive cooling of the cylinders 6.

[0040] Also, the strength of the first and third cylinders 6 can be improved because the outer and inner parts of the block-side cooling water jacket 5 are integrated by the notches 25-28. Also, each cylinder 6 is in the same state as if it had bore-to-bore portions 7 formed at both the front and rear ends, which also contributes to suppressing distortion.

[0041] As in the embodiment, the block side cooling water jacket 5 is provided at the front and rear end portions. Second Forming the notches 27, 28 can prevent the cooling water from entering the block side cooling water jacket 5 too much, improving the flow straightening function.

[0042] Now, when the cylinder 6 and the cylinder head 2 are integrated, heat is transferred when there is a temperature difference between the cylinder head 2 and the cylinder 6. In this case, the cylinder head 2 becomes hot on the exhaust side, so that a temperature difference is also likely to occur in the cylinder 6 between the exhaust side and the intake side.

[0043] Regarding this point, in this embodiment, on the intake side, the communication area between the intake side portion 19a and the bore upper portion 19b of the lower-stage head side cooling water jacket 19 is reduced to suppress cooling of the cylinder 6, while on the exhaust side, the center portion 19b and the exhaust side portion 19c of the lower-stage head side cooling water jacket 19 are communicated with the block side cooling water jacket 5 to improve the cooling performance of the upper portion of the cylinder 6 and the vicinity of the exhaust port 9. Therefore, the temperature difference between the intake side and exhaust side in the upper portion of the cylinder 6 is reduced as much as possible, and the occurrence of distortion due to heat can be suppressed.

[0044] In this embodiment Is, cut By adjusting the number and depth of the notches 25 to 28, the flow of the cooling water can be optimized.

[0045] Although the embodiment of the present invention has been described above, the present invention can be embodied in various other ways. [Industrial Applicability]

[0046] The present invention can be embodied in a monoblock engine, and therefore has industrial applicability. [Explanation of symbols]

[0047] 1 Cylinder block 2. Cylinder head 3 Body block 5 Block side cooling water jacket 6-cylinder 19 Lower head side cooling water jacket 19a Intake side part 19b Center part 20 Upper head side cooling water jacket 22 Cooling water outlet 23 Cooling water inlet 24 Aisle 25 front 1st cut Notch 25a,25b 3rd notch 26 Rear No. 1 Notch 27,28 Second Notch

Claims

1. A cylinder block is integrated with a cylinder head and has a group of cylinder bores that open downward and a block-side cooling water jacket that surrounds the group of cylinder bores. The cylinder head is formed with a head-side cooling water jacket that is directly connected to the block-side cooling water jacket, a cooling water inlet that is long in the cylinder row direction is provided at an upper end of the block side cooling water jacket near one end of the cylinder row, or at a lower end of the head side cooling water jacket near one end of the cylinder row, so as to straddle a first cylinder and a second cylinder as viewed from one end of the cylinder row, Furthermore, a first notch that is located on the center line of the cylinder row and opens downward, and a second notch that is located circumferentially away from the first notch and opens downward are formed on one end side and the other end side of the cylinder row of the block-side cooling water jacket, respectively. Monoblock engine.

2. A third notch opening upward in a symmetrical position to the first notch is formed on each of the sides of one end of the cylinder row and the other end of the head side cooling water jacket.

2. A monoblock engine according to claim 1.

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