JPH10169438A - Piston cooling device for multiple cylinder engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a compact oil pump of small displacement usable without impairing piston cooling performance by opening communicating holes piercingly in crankshaft support walls, and opening jets of oil injection nozzles to the inner surface of the communicating holes so as to spray oil to a plurality of pistons. SOLUTION: Crankshafts 27 are fitted to two side walls 30, 31 of a cylinder block 3 and partition walls 32-34, extended downward between cylinder holes 22-25, by bearing caps 35. In such constitution, the side wall 31 and the partition walls 32-34 are provided with oil injection nozzles 39-42 for injecting oil to cool pistons 29. The respective nozzles 39-42 are formed of stepped round holes bored in the walls 31-34 so as to force-feed oil from an oil pump through a main oil passage and branch passages formed in the cylinder block 3. The respective nozzles 39-42 are formed in the inclined state of axes so that oil is injected into the cylinder holes 22-25 positioned on the left side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston cooling device for a multi-cylinder engine in which oil is sprayed on a piston from a support wall for a crankshaft of a cylinder block by a nozzle.

[0002]

2. Description of the Related Art Conventionally, as a piston cooling device of this type, for example, as disclosed in Japanese Utility Model Laid-Open Publication No. 56-27315, oil is injected into a wall of a cylinder block facing a cylinder hole in a crankshaft support wall. In many cases, a structure is adopted in which the injection port of the nozzle is opened to inject oil pumped from an oil pump into the cylinder hole from the injection port. When this piston cooling device is applied to a multi-cylinder engine, an oil injection nozzle is provided for each cylinder, and a structure is employed in which oil is sprayed from a dedicated nozzle to each piston, so that an oil amount corresponding to the number of cylinders can be obtained. Large oil pumps must be used.

[0003]

However, the multi-cylinder engine employing the above-described conventional piston cooling device cannot be reduced in size because the capacity of the oil pump cannot be reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and has been made to reduce the size of a multi-cylinder engine by using a small-capacity and small oil pump without impairing the cooling performance of a piston. The purpose is to aim.

[0005]

In a piston cooling device for a multi-cylinder engine according to the present invention, a communication hole penetrating the crankshaft support wall is opened, and an injection port of an oil injection nozzle is connected to the communication hole. It is an opening on the inner surface. When the piston descends in the intake stroke and the expansion stroke, the gas in the cylinder hole flows to the adjacent cylinder hole side through the communication hole, so that part of the oil injected from the nozzle is adjacent to the gas flow. It is blown into the cylinder bore. Also, the oil directly injected into the cylinder hole without riding on the gas flow is also blown into the adjacent cylinder hole by the gas flow when it falls after being sprayed on the piston.

Accordingly, the oil injected from one nozzle can be sprayed on a plurality of pistons by utilizing the flow of gas generated in the crank chamber. Therefore, even if the amount of oil injected is small, the plurality of pistons can be reliably used. Can be cooled.

A piston cooling device for a multi-cylinder engine according to another aspect of the invention is the piston cooling device for a multi-cylinder engine described above, wherein the injection direction of the oil injection nozzle is directed to a portion of the piston corresponding to the exhaust side of the cylinder head. Direction. ADVANTAGE OF THE INVENTION According to this invention, oil can be sprayed on the hottest part of a piston.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a piston cooling device for a multi-cylinder engine according to the present invention will be described below with reference to FIGS.
This will be described in detail. FIG. 1 is a longitudinal sectional view of a multi-cylinder engine employing a piston cooling device according to the present invention. FIG. 2 is a sectional view taken along line II-II of the cylinder block in FIG. 3 shows a broken position of a cylinder block. FIG. 3 is a plan view of the cylinder block.

FIG. 4 is a side view showing an intake manifold mounting portion, FIG. 5 is a sectional view taken along the line V--V in FIG. 4, FIG. 6 is a view showing an engine hanger, and FIG. (b) is a front view, and (c) is a side view. FIG. 7 is a perspective view of the engine hanger.

In these figures, reference numeral 1 denotes a four-cylinder engine according to this embodiment, reference numeral 2 denotes a cylinder head of the engine 1, and reference numeral 3 denotes a cylinder block. The cylinder head 2 has a structure in which two intake valves 4 and two exhaust valves 5 are driven by an intake camshaft 6 and an exhaust camshaft 7 for each cylinder. Reference numeral 8 denotes an injector for fuel injection, 9 denotes a spark plug, 10 denotes an intake manifold, and 11 denotes an exhaust manifold. As shown in FIG. 4, the intake manifold 10 includes a surge tank 12 and an intake distribution pipe 13 for each cylinder.
And are integrally formed of a synthetic resin.

The intake manifold 10 is attached by fixing the surge tank 12 to the cylinder block 3 with fixing bolts 14 and fixing the flange 13 a at the downstream end of the intake distribution pipe 13 to the cylinder head 2 with fixing bolts 15. We are implementing. The part where the surge tank 12 is mounted on the cylinder block 3 has a spacer 16 interposed between the surge tank 12 and the side surface of the cylinder block 3 as shown in FIG. The spacer 16 has a structure for closing the concave portion 17 of the cylinder block 3 and forms a blow-by gas oil separation chamber 18 therein. Reference numeral 19 provided in the oil separation chamber 18
What is indicated by is a plate for separating oil from blow-by gas.

In FIG. 4, the intake manifold 10
A wire 20 (not shown) is provided when the engine 1 is assembled and transported.
It is an engine hanger for hanging. The engine hanger 20 is attached to two places on the side of the cylinder head 2. The disposition positions of these engine hangers 20 are set so as to be positioned diagonally when the cylinder head 2 is viewed from above. An ignition coil 21 is attached to one of these engine hangers 20, as shown in FIGS.

That is, the engine hanger 20 is
The ignition coil 21 is formed so as to also serve as a bracket for attaching to the engine 1. In FIG.
Reference numeral 0a denotes a fixing bolt for fixing the engine hanger 20 to the cylinder head 2. With this structure, the screw portion for mounting the ignition coil 21 does not need to be formed in the cylinder head 2, so that the weight of the cylinder head 2 can be reduced. In addition, a bracket used exclusively for attaching the ignition coil 21 to the cylinder head 2 is not required, and the number of parts can be reduced.

As shown in FIGS. 1 to 3, the cylinder block 3 has four cylinder holes 22 to 25 at an upper portion and a crank chamber 26 at a lower portion. Is rotatably mounted. An oil pan (not shown) is attached to the lower surface of the cylinder block 3.

The cylinder holes 22 to 25 are formed so as to be arranged in a line along the axial direction of the crankshaft 27. In this embodiment, the four cylinder holes 22 to
25, the leftmost cylinder hole 22 in FIGS.
The cylinder constituted by the cylinder hole 23 is called a # 1 cylinder, and the cylinder constituted by the cylinder hole 23 is called a # 2 cylinder. Also,
The cylinder constituted by the cylinder hole 24 is called # 3 cylinder, and the cylinder constituted by the cylinder hole 25 is called # 4 cylinder.

The crankshaft 27 is formed so that the phase of a piston 29 connected via a connecting rod 28 is the same in the # 1 cylinder and the # 4 cylinder, and is the same in the # 2 cylinder and the # 3 cylinder. doing. The # 2 and # 3 cylinders have a crank angle of 1 with respect to the # 1 and # 4 cylinders.
It is shifted by 80 °. The crankshaft 27 has two side walls (walls at both ends in the axial direction of the crankshaft 27) 30, 31 of the cylinder block 3, and partition walls 32-34 extending downward between the cylinder holes 22-25. And the bearing cap 35. A flat bearing 36 is interposed in a portion where the crankshaft 27 is mounted, as is well known in the art. The bearing caps 35 are connected to each other by a bearing beam indicated by reference numeral 37. The side walls 30, 31 and the partition walls 32 to
Reference numeral 34 denotes a crankshaft support wall according to the present invention.

The partition walls 32 to 34 are formed so as to partition the cylinder hole side of the crank chamber 26 for each cylinder. The partition walls 32 positioned between the # 1 and # 2 cylinders, the # 3 and # 4 In the partition wall 34 located between the cylinders, a communication hole 38 penetrating therethrough is formed above the bearing of the crankshaft 27. That is, the cylinder block 3 has a structure in which two cylinders (for example, # 1 cylinder and # 2 cylinder) adjacent to each other and having different phases communicate with each other via the communication hole 38 in the crank chamber 26. I have.

One of the two side walls 30 and 31 and one of the partitions 32 to 34 are provided with an oil injection nozzle 39 for injecting oil for cooling the piston 29.
To 42 are provided. These nozzles 39 to 42 are formed by stepped round holes formed in the walls 31 to 34, and are provided with a main oil passage 43 and a branch passage 44 formed in the cylinder block 3 as shown in FIG. The structure is such that oil is pumped from a pump (not shown). This oil pump uses a trochoid type, and the crankshaft 27 is driven to drive the main oil passage 4.
A structure is adopted in which oil is pumped to 3. That is, the rotation speed of the oil pump changes according to the rotation speed of the crankshaft 27, and the pressure of the oil in the main oil passage 43 and the branch passage 44 increases according to the engine rotation speed.

The nozzles 39 to 42 are provided with a check valve (not shown) in the large diameter portion on the upstream side. The check valve has a structure that opens when the pressure on the branch path 44 side becomes higher than a predetermined pressure. That is, the pressure of the oil in the main oil passage 43 and the branch passage 44 increases with an increase in the engine speed, and when the oil reaches a predetermined pressure, the check valve is opened and the oil from each of the nozzles 39 to 42 enters the cylinder hole. It is injected.

The nozzles 39 to 42 have their axes aligned with the axes of the cylinder holes 22 to 25 so that oil is injected into the cylinder holes 22 to 25 located on the left side in FIGS. While tilting against
The axis is inclined toward the exhaust system so that the injected oil is sprayed on a portion of the piston 29 corresponding to the exhaust side of the cylinder head 2. The range in which the oil is injected is indicated by a two-dot chain line A in the figure.

Further, of these nozzles 39 to 42, the nozzles 39 and 41 formed in the partition wall 32 and the partition wall 34 have an oil injection port opened in the inner surface of the communication hole 38, and the other nozzles 40 and 42 have the partition wall An oil injection port is opened on the lower surface of the step portion 45 formed on the side wall 31 and the step 33. Nozzle 3
Reference numerals 39a to 42 in FIG.
Indicated by a.

The piston cooling device configured as described above
During operation of the engine, oil is injected from the nozzles 39 to 42 into the respective cylinder holes 22 to 25 and sprayed on the lower surfaces of the pistons 29, so that the pistons 29 can be cooled by the oil. Further, in the engine 1, when the piston 29 descends during the intake stroke and the expansion stroke of each cylinder, the gas (blow-by gas) in the cylinder holes 22 to 25 is pushed out to the crank chamber 26 and communicates with the adjacent cylinder holes. Blow through hole 38.

For example, when the piston 29 of the # 1 cylinder descends from the position shown in FIG. 2, the gas in the cylinder hole 22 of the # 1 cylinder blows into the crank chamber 26 of the # 2 cylinder through the communication hole 38. At this time, since the piston 29 of the # 2 cylinder is raised, the gas blown from the communication hole 38 is #
It is sucked into the upper part of the cylinder hole 23 of the two cylinders. Although no wall is provided below the crank chamber 26 to partition between the cylinders, the cylinder holes 22 to 2 are not provided.
The gas flowing into the crank chamber 26 from the crankshaft 27
Since the piston 29 of the # 1 cylinder descends and is pushed down from the cylinder hole 22 into the crank chamber 26, almost all of the gas is prevented from being blown from the upper part to the lower part of the crank chamber by being hindered by the communication hole. Pass through 38.

When the gas flows through the two communication holes 38 from left to right in FIG. 2, a part of the oil injected from the oil injection ports 39a and 41a opened on the inner surface of the communication holes 38 rides on the flow of the gas. And adjacent cylinder hole 2
3 and 25, and is blown to the piston 29 in the cylinder holes 23 and 25. Also, the oil directly injected into the cylinder holes 22 and 24 from the oil injection ports 39a and 41a without riding on the flow of the gas also falls when it is sprayed on the piston 29 or after it bounces off the piston 29, The gas is blown into the adjacent cylinder holes 23 and 25 by the flow of the gas.

Therefore, oil injected from one nozzle (nozzle 39 or nozzle 41) is supplied to the crank chamber 2
The plurality of pistons 29 utilizing the flow of gas generated in
, It is possible to reliably cool the plurality of pistons 29 even if the amount of oil injected is small. For this reason, the capacity of the oil pump may be smaller than before.

When the gas flows through the two communication holes 38 in the opposite direction to the above, the oil which is injected from the nozzles 40 and 42 and sprayed onto the pistons 29 of the # 2 and # 4 cylinders and then falls down. Also, the oil that has bounced off the pistons 29 rides on the gas flow and
, And is blown to the pistons 29 of the # 1 cylinder and the # 3 cylinder. Therefore, the pistons of the two cylinders adjacent to each other can be cooled by the oil injected from the two nozzles, so that the reliability is high.

Further, in this piston cooling device, since the injection direction of the oil injection nozzles 39 to 42 is directed to a portion corresponding to the exhaust side of the cylinder head 2 in the piston 29, the portion of the piston 29 where the temperature is highest becomes high. The piston 29 can be efficiently cooled even with a small amount of oil.

In the above-described embodiment, an example in which the oil injection nozzle is provided for each cylinder has been described. However, the piston cooling device according to the present invention has one nozzle in the cylinder hole of two cylinders adjacent to each other. Can be configured to inject oil. In the case of adopting this configuration, the nozzles 39, 41 are not provided without the nozzles 40, 42 shown in FIG.
Are formed so as to inject oil into the cylinder holes located on both sides of each. That is, the nozzles 39,
Each of the oil passages 41 has a V-shaped cross section, and the oil injection port at the upper end of one side of the V-shape in this oil passage is connected to the left cylinder hole (# 1 cylinder, # 3 cylinder).
While pointing to the cylinder holes 22 and 24) of the cylinder,
Insert the oil injection port at the upper end of the other side into the right cylinder hole (#
It is directed to the cylinder holes 23 and 25 of the two cylinders and the # 4 cylinder. In this case, the four oil injection ports are also opened on the inner surface of the communication hole 38 in this configuration.

[0029]

According to the piston cooling device for a multi-cylinder engine according to the present invention, a communication hole penetrating the crankshaft support wall is opened, and an injection port of an oil injection nozzle is opened on an inner surface of the communication hole. Therefore, when the piston descends in the intake stroke and the expansion stroke, the gas in the cylinder hole flows to the adjacent cylinder hole side through the communication hole, and part of the oil injected from the nozzle rides on the gas flow. It is blown into the adjacent cylinder hole. Also, the oil directly injected into the cylinder hole without riding on the gas flow is also blown into the adjacent cylinder hole by the gas flow when it falls after being sprayed on the piston.

Therefore, the oil injected from one nozzle can be sprayed on a plurality of pistons by utilizing the flow of gas generated in the crank chamber. Therefore, even if the oil injection amount is small, the plurality of pistons can be reliably used. Can be cooled. For this reason, the capacity of the oil pump may be smaller than in the past, and the engine can be downsized by using a small oil pump while preventing the cooling performance of the piston from being impaired.

A piston cooling device for a multi-cylinder engine according to another invention is the piston cooling device for a multi-cylinder engine described above, wherein the injection direction of the oil injection nozzle is directed to a portion of the piston corresponding to the exhaust side of the cylinder head. Since the direction is set, oil can be sprayed on the hottest part of the piston, so that the piston can be efficiently cooled even with a small amount of oil.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a multi-cylinder engine employing a piston cooling device according to the present invention.

FIG. 2 is a sectional view taken along line II-II of the cylinder block in FIG.

FIG. 3 is a plan view of a cylinder block.

FIG. 4 is a side view showing an intake manifold mounting portion.

FIG. 5 is a sectional view taken along line VV in FIG.

FIG. 6 is a view showing an engine hanger.

FIG. 7 is a perspective view of an engine hanger.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Cylinder head, 3 ... Cylinder block, 22-25 ... Cylinder hole, 26 ... Crank chamber, 2
7 ... crankshaft, 29 ... piston, 30, 31 ... side wall,
32 to 34 ... partition walls, 38 ... communication holes, 39 to 42 ... nozzles.

Claims (2)

[Claims] In a piston cooling device for a multi-cylinder engine, a crankshaft support wall for partitioning a crank chamber of a cylinder block for each cylinder is provided, and a nozzle for injecting oil into a cylinder hole is provided on the support wall. A piston cooling device for a multi-cylinder engine, wherein a communication hole penetrating the wall is opened, and an injection port of the nozzle is opened on an inner surface of the communication hole. 2. The multi-cylinder engine piston cooling device according to claim 1, wherein the nozzle has a structure in which the injection direction is directed to a portion of the piston corresponding to the exhaust side of the cylinder head. Piston cooling device.