JPH04318259A - Oil-cooled multi-cylinder engine - Google Patents

Abstract

PURPOSE:To eliminate insufficiency of supplying oil due to position displacement by cutting a flange part of each adjacent cylinder liner in a chord direction, and further bringing each notched edge into contact with each other so that each cylinder liner is easily and surely positioned about a cylinder axial line. CONSTITUTION:Oil is allowed to flow from a liner oil supplying oil gallery 30 into supply oil holes 40 and circumferential grooves 36 in the peripheral surface of a cylinder liner 20, and the oil, after cooling the cylinder liner 20, flows down into an oil pan. On the other hand, cooling water flows in a cooling chamber in a cylinder head to cool an exhaust port and an exhaust valve or the like. Here-in a flange part 34 of each adjacent cylinder liner 20, the periphery is partly notched in a chord direction. Each notched edge 48 is closely attached to each other. In this way, an inlet side vertical oil groove 38 of each cylinder liner 20 is always properly connected to the supply oil hole 40. Accordingly, in the case of the above-mentioned connection becoming imperfect, generation of trouble such as seizure or the like due to supply short of oil can be surely eliminated.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil-cooled multi-cylinder engine in which the cylinder portions of the engine are cooled by oil.

0002

[Prior Art] In a multi-cylinder engine equipped with a cylinder liner such as a diesel engine for a vehicle, a large number of circumferential grooves or spiral grooves are provided on the outer wall surface of the hollow cylindrical liner. Oil-cooled engines that circulate cooling oil have already been proposed. (For example, see Utility Model Registration Application No. 60967 of 1988) A typical cylinder liner mounting structure in the above-mentioned conventional oil-cooled multi-cylinder engine will be explained with reference to FIG.
2 is a cylinder liner having a hollow cylindrical shape as a whole, and 2 is a cylinder bore portion of a crankcase 3 into which the cylinder liner 1 is fitted. The cylinder liner 1 has a flange portion 4 extending radially outward at one end portion on the cylinder head side, and a large number of circumferential grooves or spiral grooves on the outer wall surface in contact with the bore portion 2 of the crankcase. 5 is formed. The circumferential grooves or spiral grooves 5 are communicated with each other by a vertical oil groove 6 extending in the cylinder axis direction on the outer wall surface of the cylinder head, and the vertical oil groove 6 is connected to the crankcase 3. It communicates with an oil supply hole 7 provided inside. The flange portion 4 of the cylinder liner 1 is received in a counterbore portion 8 cut into the open end of the bore portion 2 on the cylinder head side, that is, the upper surface of the crankcase 3.

After the cylinder liner 1 is fitted into the cylinder bore 2 of the crankcase, a cylinder head is mounted on the upper surface of the crankcase via a head gasket (not shown), and a head bolt is tightened.
Although it is temporarily fixed to the crankcase 3, since the outer circumferential shape of the flange portion 4 is circular, the cylinder liner 1 rotates around its axis due to vibrations generated during engine operation. There are concerns. If cylinder liner 1
is rotated around the axis from the original normal mounting position,
The vertical oil groove 6 on the outer wall of the liner and the oil supply hole 7 in the crankcase will not communicate properly, and there is a risk that the flow rate of the cooling oil will be insufficient, leading to burnout of the engine. As a means of reliably preventing rotation of the cylinder liner 1 around the axis, the most common method is to drive a dowel pin 9 into the appropriate position of the flange portion 4, as shown by the dashed line in FIG. However, since it is necessary to drill a pin hole in both the flange portion 4 and the crankcase 2, perform centering, and then fold in the knock pin 9, there is a problem that the manufacturing cost increases.

0004

[Problems to be Solved by the Invention] The present invention was devised in view of the above-mentioned problems in conventional oil-cooled multi-cylinder engines. The purpose is to provide a simple and inexpensive configuration that can be used.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a groove for circulating cooling oil on the outer wall surface thereof, and a groove extending radially outward at one end on the cylinder head side. In a cylinder liner having a flange portion fitted into the cylinder bore portion of the crankcase, a portion of the flange portion of the adjacent cylinder liner is cut out in the chord direction, and the cut edges are brought into contact with each other. The present invention proposes an oil-cooled multi-cylinder engine characterized in that each cylinder liner is positioned around the cylinder axis by bringing them into contact with each other.

[0006]

[Operation] According to the present invention, a portion of the flange portions of adjacent cylinder liners are notched in the chord direction and the notched edges are brought into contact with each other, so that the adjacent cylinder liners rotate around their respective axes. They will be irreversibly interconnected, in other words positioned around the cylinder axis.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described in detail below with reference to FIGS. 1 to 5. In the figure, reference numeral 10 generally indicates a direct injection multi-cylinder diesel engine for trucks, and 12
1 is a crankcase of the engine, 14 is a cylinder head mounted on the upper end of the crankcase 12, and 16 is a well-known ladder frame or underframe that is mounted on the lower end of the crankcase 12 and has a substantially ladder-like planar shape. , 18 are the cylinder head 14 and the crankcase 12.
A large number of head bolts 20 extend parallel to the cylinder axis and tighten them together through the ladder frame 16 and are fitted into the cylinder bore 22 formed in the crankcase 12 and are hollow as a whole. A cylinder liner having a cylindrical shape, 24 is the same cylinder liner 20
A piston 26 fitted therein has a connecting rod 28 whose one small end is connected to the piston 24.
30 is a crankshaft connected to the other large end of the connecting rod 26, and 30 is a liner oil supply extending in the direction of the crank axis near the upper end of the crankcase 12 and connected to an oil pump (not shown). oil gear for
A main oil gear 32 is formed on a side wall portion of the crankcase 12 adjacent to the lower liner portion and extends in the crank axial direction.

[0008] The cylinder liner 20 is provided with a flange portion 34 extending radially outward at the end thereof on the cylinder head 14 side, and the outer wall surface excluding the flange portion 34 has a In the illustrated embodiment, a large number of circumferential grooves 36 are formed at appropriate intervals in the cylinder axis direction. These circumferential grooves 36 have an angular interval of approximately 180 degrees in the circumferential direction on the outer wall surface of the liner, as disclosed in detail in the previously proposed invention or invention, for example, in Utility Model Application No. 62-60967. The liner oil supply oil gear 30 is divided into one or more appropriate number of passage groups by an inlet side vertical oil groove 38 (see FIG. 4) and an outlet side vertical oil groove (not shown), which are formed to extend in the direction. The cooling oil supplied to the uppermost inlet side vertical oil groove 38 through the oil supply hole 40 is divided into right and left sides in the circumferential direction, makes a half turn inside the circumferential groove 36, and flows out into the outlet side vertical oil groove. If there are two or more groups of passages,
The cooling oil that has flowed out into the vertical oil groove on the outlet side of the first group then enters the vertical oil groove on the inlet side of the second group, and in the same manner flows in the circumferential grooves 36 of the lower groups in order to form the outer wall surface of the liner. The oil may flow directly into the oil pan from an oil outlet 42 provided in the lower part, or may be collected in an oil drain gear 44, shown in dotted lines in FIG. 1, and then flowed into the oil pan. The oil discharge gear lary 44 is similar to the liner oil supply oil gear lary 30, and is connected to the crankcase 12.
is bored in the side wall of the engine, extending in the direction of the crank axis.

In this embodiment, as clearly shown in the partially enlarged cross-sectional view of FIG. , and its upper surface 34b
is in contact with the lower surface of the cylinder head 14 via a suitable gasket, for example a thin laminate gasket 46. Furthermore, as clearly shown in the top plan view of the crankcase in FIG. 2 and the enlarged plan view of the main part in FIG. , the respective notch edges 48 are brought into close contact with each other. In FIG. 2, reference numeral 50 indicates a bolt hole through which the head bolt 18 is inserted, and 52 indicates an outer wall surface of the crankcase 12 at the cylinder bore portion.

In the above structure, during operation of the engine, oil is supplied to the liner oil supply oil gear 30 by an oil pump (not shown), and oil is provided through oil supply holes 40 formed in the outer wall surfaces of the liners 20 of the plurality of cylinders, respectively. The oil flows through the circumferential groove 36 as described above, cools the liner, and then flows down into the oil pan. On the other hand, a cooling water chamber 54 is provided inside the cylinder head 14 (see FIG. 1), and cooling water pumped by a water pump (not shown) flows through the cooling water chamber 54 inside the cylinder head 14. After cooling the exhaust port, exhaust valve, etc., the water is returned to the water pump via the radiator.

Now, as described above, the flange portions 34 of the adjacent cylinder liners 20 are provided so that a portion of their outer periphery is cut out in the chord direction, and the cut edges 48 are in close contact with each other. As shown in FIG. 2, each cylinder liner 20 is fitted into the cylinder bore portion of the crankcase 12.
are non-rotatably positioned about their respective cylinder axes. Therefore, the vertical oil groove 38 on the inlet side of each cylinder liner 20
and an oil supply hole 4 communicating with an oil gear rally 30 for liner oil supply.
The oil supply that occurs when the cylinder liner 20 unexpectedly rotates around the cylinder axis and the connection between the vertical oil groove 38 and the oil supply hole 40 becomes incomplete. It is possible to reliably avoid the occurrence of problems such as burn-in caused by the shortage. Furthermore, notching the flange portion 34 is extremely easy, and the processing cost is significantly lower than drilling a knock pin hole in the flange portion 34 and crankcase 12, which is normally done for positioning. Positioning is performed automatically by sequentially inserting into the cylinder bore portion in a predetermined direction, and additional work such as driving a dowel pin is not required, so assembly work costs are also reduced.

Furthermore, by providing a notch in a part of the outer periphery of the adjacent cylinder liner flange portions 34 as described above, the effective inner diameter of the cylinders arranged in a row with a given constant bore interval can be reduced. That is, while ensuring the inner diameter of the cylinder liner 20 to the maximum extent possible, the flange width f (see FIGS. 2 and 3) of the flange portion other than the above-mentioned notch is made sufficiently large, thereby increasing the area of the upper side surface 34b and the lower side surface 34a. As a result, the surface pressure between the flange lower surface 34a and the crankcase upper surface 12a caused by tightening the head bolt 18 and the flange portion upper surface 34b can be increased.
The surface pressure between the gasket 46 and the gasket 46 is lowered to the necessary and sufficient limit for cooling oil sealing and gas sealing, respectively, to prevent damage due to material settling, etc., and improve engine durability and reliability. can do.

In the illustrated embodiment, as shown in FIG. 5, the flange portion 3 of the cylinder liner 20
4 is placed directly on the crankcase upper surface 12a,
As shown in FIG. 6, compared to the normal structure in which the cylinder liner flange portion 4 is fitted into the counterbore portion 8, the crankcase upper surface 12a and the cylinder liner upper surface of the plurality of cylinders, that is, the flange portion upper surface 34b. There is an additional advantage that the height variation between the cooling oil and gas seals is significantly reduced, which can effectively improve the performance of the cooling oil seal and gas seal. This means that the flange portion 34 of the cylinder liner 20
Dimensions in the cylinder axial direction and the upper surface of the crankcase 12
Compared to the error in plane machining in a, the counterbore portion 8 in FIG.
This is based on the fact that the machining accuracy in the depth direction is usually extremely low. Furthermore, in the illustrated embodiment, there is no need to process the counterbore portion 8 for receiving the flange portion 34 of the cylinder liner 20 into the crankcase 12, so that it is possible to achieve a reduction in processing cost commensurate with the counterbore processing cost. is self-evident.

Furthermore, in the above embodiment, a circumferential groove 36 is provided on the outer wall surface of the cylinder liner 20 to allow cooling oil to flow therethrough.
However, the present invention can of course be applied to a case where a spiral groove is provided on the outer wall surface of the cylinder liner 20. Further, in the present invention, the circulation pattern of the cooling oil is changed in various ways, such as by partially changing the cross-sectional area or changing the arrangement interval of the circumferential groove or the spiral groove according to the heat load on each part of the cylinder liner. Can be widely applied to all engines with oil-cooled liners. Furthermore, in the illustrated embodiment, the cutout edge 48 of the flange portion 34 is formed on a flat surface that is easiest to process, but it may be formed on a curved surface extending in the chord direction.
It can have an appropriate shape such as a wavy surface.

Effects of the Invention As described above, the oil-cooled multi-cylinder engine according to the present invention is provided with grooves for circulating cooling oil on its outer wall surface, and grooves extending radially outward at one end on the cylinder head side. In a cylinder liner fitted with a flange portion extending to the cylinder bore portion of the crankcase, a portion of the flange portion of the adjacent cylinder liner is cut out in the chord direction, and the cut edges are mutually connected. It is characterized by positioning each cylinder liner around the cylinder axis by bringing the cylinder liners into contact with the cylinder liner. This is extremely useful industrially because it can provide a simple and inexpensive configuration that can effectively prevent seizure and the like and improve the durability and reliability of the engine.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention.

FIG. 2 is a top plan view of the crankcase of the engine shown in FIG. 1;

FIG. 3 is an enlarged plan view of a portion surrounded by a dashed-dotted circle III in FIG. 2;

4 is an enlarged plan view, partially in cross section, of a portion surrounded by a dashed-dotted circle IV in FIG. 2; FIG.

FIG. 5 is a partially enlarged sectional view taken along line V-V in FIG. 2;

FIG. 6 is an enlarged sectional view of a cylinder liner attachment portion in a conventional oil-cooled engine.

[Explanation of symbols]

10 Multi-cylinder diesel engine 12 Crank case 14 Cylinder head 16 Ladder frame 20 Cylinder liner 30 Oil gear lary for liner oil supply 34
Flange portion 36 Circumferential groove 38 Vertical oil groove 48 Notch edge of flange portion

Claims (1)

[Claims] Claim 1: A cylinder liner having a groove for circulating cooling oil on its outer wall surface and a flange portion extending radially outward at one end on the cylinder head side is attached to the cylinder bore of the crankcase. In the cylinder liner, each cylinder liner is positioned around the cylinder axis by notching a part of the flange part of the adjacent cylinder liner in the chord direction and bringing the notch edges into contact with each other. Oil-cooled multi-cylinder engine characterized by