JPH0763028A - Lubricating device for internal combustion engine - Google Patents

Abstract

PURPOSE:To promote heat exchange of lubricating oil and cooling water, and suppress increasing of an oil temperature at the time of a high speed and high load. CONSTITUTION:A main oil pump 1 is provided to forcibly feed lubricating oil collected on an oil pan 2 to each part of an engine, A return passage 9 is formed from the oil reservoir part 5 of a cylinder head 4 upper surface on which lubricating oil having lubricated a valve system collects toward the oil pan 2, and a water jacket 10 is arranged around the return passage 9. A returning oil pump 11 which consists of a plunger pump driven by a cam shaft 7 is provided on a return passage 9 so as to return back forcibly lubricating oil toward the oil pan 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a lubricating device for an internal combustion engine in which lubricating oil collected in an oil pan is forcedly lubricated by pressure-feeding it to various parts of the engine by an oil pump.

[0002]

2. Description of the Related Art In a general internal combustion engine represented by an internal combustion engine for an automobile, a lubricating device of a forced lubrication system in which an oil pump driven by an engine output sucks lubricating oil from an oil pan and pressure-feeds it to various parts of the engine. Has been adopted. In this type of lubricating device, the lubricating oil discharged from the oil pump, after passing through the oil filter, is supplied to the periphery of the main shaft on the cylinder block side through the main gallery and to the valve operating system on the cylinder head side. It is roughly divided into two parts. Then, after lubricating the valve operating system, the lubricating oil supplied to the cylinder head side temporarily gathers in the oil sump portion on the upper surface of the top deck of the cylinder head, and as shown in Japanese Utility Model Publication No. 61-166110. To
It is designed to return to the oil pan by gravity-driven natural flow through a return passage that vertically penetrates the cylinder head and the cylinder block.

[0003]

In the lubricating device for an internal combustion engine as described above, in order to ensure the lubricating performance, it is necessary to avoid excessive temperature rise of the lubricating oil, that is, under high speed and high load conditions. It is necessary to suppress the rise in oil temperature.

Here, in order to satisfactorily cool the periphery of the combustion chamber on the cylinder head side, a wide water jacket is provided, and cooling is performed positively by flowing cooling water, so valve system lubrication is performed. Therefore, the lubricating oil supplied to the cylinder head side is strongly subjected to the cooling action. Therefore, if the amount of lubricating oil supplied to the cylinder head side is increased, heat exchange between the cooling water and the lubricating oil is promoted, and an increase in the oil temperature of the entire lubricating oil at high speed and high load can be suppressed.

However, in the conventional lubrication device, as described above, the lubricating oil collected in the oil sump portion of the cylinder head flows down through the return passage by its own weight, so that it is difficult to secure a sufficient return flow rate. Therefore, if a large amount of lubricating oil is supplied to the cylinder head side, a large amount of lubricating oil will accumulate in the oil sump portion of the cylinder head, which makes it difficult to process blow-by gas. Therefore, in reality, the amount of lubricating oil that goes to the cylinder head is suppressed to a small amount by the orifice, and the cooling action of the water jacket on the cylinder head side cannot be effectively utilized.

[0006]

Therefore, according to the present invention,
By forcibly returning the lubricating oil from the cylinder head side to the oil pan, a large amount of lubricating oil was supplied to the cylinder head side to promote cooling. That is, a lubricating device for an internal combustion engine according to the present invention includes a main oil pump that pumps lubricating oil collected in an oil pan to each part of the engine, and a return oil that returns the lubricating oil from the oil sump part of the cylinder head to the oil pan. And a return oil pump is constituted by a plunger pump driven by a cam shaft supported by a cylinder head.

According to the second aspect of the invention, the water jacket is arranged around the return passage extending from the return oil pump to the oil pan.

[0008]

The return oil pump, which is a plunger pump, is driven by the cam shaft of the cylinder head and forcibly returns the lubricating oil from the oil sump of the cylinder head to the oil pan. Therefore, a sufficiently large return flow rate from the cylinder head can be ensured, and the amount of oil supplied to the cylinder head can be correspondingly increased. The lubricating oil supplied to the cylinder head is effectively cooled by heat exchange with the cooling water flowing through the water jacket in the cylinder head. In particular, if the water jacket is provided around the return passage as in the second aspect, the cooling thereof is further promoted.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a structural explanatory view showing an embodiment of a lubricating device according to the present invention. The main oil pump 1
It is composed of a gear type pump or the like driven by an engine crankshaft, and sucks up lubricating oil stored in an oil pan 2 through a strainer 3 and pumps it to each part of the engine. The oil pan 2 is mounted on the lower surface of the cylinder block, and the lubricating oil flowing from each part into the crankcase is collected by the oil pan 2. As will be described later, the lubricating oil discharged from the main oil pump 1 passes through an oil filter and then is supplied to the periphery of the main shaft on the cylinder block side through the main gallery and the valve system on the cylinder head 4 side. It is divided into two parts, the flow supplied to

On the top surface of the top deck 4a of the cylinder head 4, there is formed an oil sump portion 5 for collecting lubricating oil after lubrication of the valve system. A camshaft 7 is rotatably supported by a cam bracket portion 6 of the cylinder head 4, and the cam portion 7a opens and closes intake and exhaust valves via a hydraulic valve lifter 8.

An oil pan 2 is provided on the lower surface of the oil reservoir 5.
One end of the return passage 9 for returning the lubricating oil to is open.
The return passage 9 extends downward through the cylinder head 4 and the cylinder block, and its tip is open toward the oil pan 2. A cooling water jacket 10 is provided inside the cylinder head 4 or the cylinder block so as to surround the return passage 9. Further, on the cylinder head 4 side, a return oil pump 11 for forcibly pumping the lubricating oil toward the oil pan 2 is interposed in the return passage 9. The return oil pump 11 is composed of a plunger pump driven by an eccentric cam 7b of a cam shaft 7, and has a housing 13 having a cylinder 12 and a slidable inside the cylinder 12, as shown in detail in FIG. The plunger 15 that is provided to define the compression chamber 14 and the plunger 15 is connected to the cam 7b.
It is composed of a return spring 16 biased to the side, a suction side check valve 17, and a discharge side check valve 18. As shown in FIGS. 2A and 2B, the return oil pump 11 performs a pumping action toward the oil pan 2 as the plunger 15 advances and retracts as the eccentric cam 7b rotates.

FIG. 3 is a block diagram showing the flow of lubricating oil in the entire internal combustion engine, and the same parts as those in FIG. 1 are designated by the same reference numerals. Explaining this along the flow of the lubricating oil, the lubricating oil sucked up from the oil pan 2 by the main oil pump 1 through the strainer 3 is sent to the main gallery 23 through the oil filter 22, and from there, it is divided into two flows. Divide. The main oil pump 1 has a regulator valve 24 and the oil filter 2
A relief valve 25 is arranged in parallel with the valve 2.

One flow from the main gallery 23 to the periphery of the main shaft lubricates the main bearing 26 and then passes through the crankshaft 27 and the connecting rod bearing 28.
Is further supplied to the piston 29 and the cylinder bore 30. Then, these lubricating oils are finally dropped into the crankcase and collected in the oil pan 2.

The flow rate of the lubricating oil flowing from the main gallery 23 to the cylinder head 4 side is adjusted by the orifice 31, and the valve lifter guide 32 to the valve lifter 8 are used.
Is supplied to the rocker shaft 33 and the rocker arm 34, and is sprayed to the camshaft 7.

In the above configuration, the amount of oil supplied to the cylinder head 4 side determined by the orifice 31 is set to be sufficiently large. Then, the large amount of lubricating oil supplied to the cylinder head 4 side is reliably returned to the oil pan 2 by the return oil pump 11 driven by the camshaft 7.

Therefore, in the above configuration, the cylinder head 4
Good heat exchange is performed between the cooling water and the lubricating oil that are actively cooling the oil, and the overall temperature of the lubricating oil can be suppressed. Moreover, since the flow velocity in the return passage 9 is increased by the pressure feeding, high thermal conductivity can be obtained. Moreover, it is easy to form the water jacket 10 around the return passage 9, and further cooling can be achieved by the water jacket 10.

Further, by driving the return oil pump 11 by the cam shaft 7, the structure is simple and the pump can be arranged in the vicinity of the oil sump portion 5 of the cylinder head 4, so that the lubricating oil can be efficiently used. Can be pumped. Then, a large proportion of the passage length downstream of the return oil pump 11 can be secured, and cooling by the water jacket 10 becomes easy.

[0019]

As is apparent from the above description, according to the lubricating device for an internal combustion engine according to the present invention, it becomes possible to supply a large amount of lubricating oil to the cylinder head side, and the lubricating oil and the cooling water can be supplied. The heat exchange can be promoted, and the oil temperature rise at high speed and high load can be suppressed. Further, by driving the return oil pump by the cam shaft, the structure is simplified and the lubricating oil can be efficiently pumped in the vicinity of the oil sump of the cylinder head.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing an embodiment of a lubricating device according to the present invention.

2A and 2B are cross-sectional views showing the structure and operation of a return oil pump.

FIG. 3 is a block diagram showing the flow of lubricating oil in the entire lubricating device.

[Explanation of symbols]

 1 ... Main oil pump 2 ... Oil pan 5 ... Oil sump 9 ... Return passage 10 ... Water jacket 11 ... Return oil pump

Claims (2)

[Claims] 1. A main oil pump for pumping lubricating oil collected in an oil pan to various parts of an engine, and a return oil pump for returning lubricating oil from an oil sump of a cylinder head to the oil pan, and the return A lubricating device for an internal combustion engine, wherein the oil pump for use is constituted by a plunger pump driven by a cam shaft supported by a cylinder head. 2. A lubricating device for an internal combustion engine according to claim 1, wherein a water jacket is arranged around a return passage extending from the return oil pump to the oil pan.