JP2001248416A - Blow-by gas return system in engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease entire height of an engine while employing a structure having an oil separator in the engine. SOLUTION: An auxiliary machine chamber 16 communicating with a crank chamber and a valve system cam chamber 18 is formed with the engine and a front cover 11 in one side part in the axial direction of a crankshaft 12 of the engine. Part of the front cover 11 is extended in the separating direction from a cylinder. The oil separator 32 is provided inside the extended part 31. A blow-by gas inlet and an oil discharge outlet of the oil separator 32 are opened in the auxiliary machine chamber 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow-by gas reducing device for an engine provided with an oil separator for separating blow-by gas and oil.

[0002]

2. Description of the Related Art As a conventional blow-by gas reducing apparatus of this type, for example, as shown in FIG. 4, an oil separator is provided on a head cover of an engine. FIG. 4 is a sectional view showing a conventional oil separator. In FIG. 1, reference numeral 1 denotes an engine head cover. The head cover 1 is formed so that a portion facing the intake camshaft 2 and the exhaust camshaft 3 bulges out to the side opposite to the cylinder head 4, and the bulge portion 5 is provided with an oil separator 6.

In the oil separator 6, a gas passage 9 is formed in a labyrinth between the valve operating chamber 7 and the blow-by gas outlet 8 by a baffle plate (not shown) formed integrally with the head cover 1. A structure is adopted in which oil particles are attached to the baffle plate and the inner wall surface of the head cover to separate blow-by gas and oil. The blow-by gas outlet 8 is formed at the uppermost portion of the head cover 1 (the portion farthest from the cylinder head 4).
A blow-by gas hose (not shown) is connected to a portion where an intake negative pressure acts, such as an air cleaner.

[0004]

However, when the oil separator 6 is provided on the head cover 1 as described above, the head cover 1 projects greatly from the cylinder head 4 and the engine becomes large in the axial direction of the cylinder. There was a problem. In order to mount this engine on an automobile, the height of the bonnet must be increased more than necessary in order to prevent a bonnet (not shown) from coming into contact with the head cover 1.

The present invention has been made to solve such a problem, and an object of the present invention is to reduce the overall height of an engine while adopting a structure in which an oil separator is provided in the engine.

[0006]

To achieve this object, a blow-by gas reducing device for an engine according to the present invention communicates with a crank chamber and a valve gear cam chamber on one side of an engine in the axial direction of a crank shaft. A part of the front cover is expanded in a direction away from the cylinder, an oil separator is provided inside the expanded part, and a blow-by gas inlet of the oil separator is formed. And an oil discharge port is opened to the auxiliary machine room.

According to the present invention, the oil mist scattered in the crank chamber and the valve operating cam chamber flows into the oil separator together with the blow-by gas from the auxiliary machine room on one side of the engine. Is separated from the blow-by gas and discharged from the oil discharge port into the auxiliary machine room. The oil separator may be formed to extend in an axial direction of the cylinder on one side of the engine.

According to a second aspect of the present invention, there is provided a blow-by gas reducing device for an engine according to the first aspect of the present invention, wherein a baffle plate is integrated with an inner surface of a bulging portion of the front cover. A partition plate for partitioning the space inside the bulging portion from the auxiliary equipment room is fixed to the front cover, and a blow-by gas inlet and an oil discharge port are formed at the lower end of the partition plate. A blow-by gas discharge port is formed at the upper end of the cover.

According to the present invention, the oil separator can be formed using the front cover. Also,
Since the oil particles rise in the oil separator against gravity, the speed of movement of the oil particles relative to the blow-by gas decreases, and the oil particles easily adhere to the baffle plate and the inner wall surface of the oil separator.

[0010]

1 to 3 show an embodiment of a blow-by gas reducing device for an engine according to the present invention.
This will be described in detail. FIG. 1 is a front view of a front cover used in the blow-by gas reducing device according to the present invention, FIG. 2 is a rear view of the front cover, and FIG. 3 is a sectional view of the front cover and the head cover in FIG.

In these figures, reference numeral 11 denotes a front cover of a water-cooled four-cycle two-cylinder engine according to this embodiment. The engine is
The engine is mounted on an automobile such that the axis of the cylinder is directed substantially vertically, and the front cover 11 is attached to one side of the engine (one end in the axial direction of the crankshaft 12).

A crankshaft 12 is provided between the front cover 11 and the engine (crankcase and cylinder).
Accessory chamber 16 for accommodating a timing chain 15 for transmitting the rotation of the shaft to the intake camshaft 13 and the exhaust camshaft 14.
(See FIGS. 2 and 3). As is well known in the art, the accessory chamber 16 includes a crank chamber formed in a crankcase, a cylinder head and a head cover 1.
7 and a valve operating cam chamber 18 formed therebetween. In addition, the timing chain 15
A tensioner 19 and a chain guide 20 are provided.

The intake camshaft 13 according to this embodiment is
A valve timing control device 21 is provided at one shaft end,
The rotation phase of the timing chain sprocket 22 provided in the valve timing control device 21 can be changed. The exhaust camshaft 14 fixes the timing chain sprocket 23 to the shaft end,
Through this sprocket 23, the timing chain 15
The rotation is transmitted from.

The crankshaft 12 penetrates through the front cover 11 and protrudes out of the cover. An alternator 24 and an air conditioner compressor 25 are provided at protruding ends of the crankshaft 12 via accessory drive chains 26 and 27, respectively. Connected. The alternator 24 and the compressor 25 are disposed so as to be distributed to one side and the other side of the engine, and the chains 26 and 27 are driven by the drive sprockets 28 and 29 of the crankshaft 12 and driven by the two auxiliary machines. The crankshaft 12 is connected to the side sprockets 24a and 25a.
Are wound so as to form a V-shape when viewed from the axial direction of the arrow.

The front cover 11 has a portion facing the cylinder partially bulging away from the cylinder, and an oil separator 32 of the blow-by gas reducing device according to the present invention is provided inside the bulging portion 31. Provided.
In this embodiment, the bulging portion 31 is formed so as to be as long as possible in the vertical direction on the front cover 11. That is, as shown in FIG. 1, the upper end of the bulging portion 31 is extended to the upper end of the front cover 11 so as to extend to the side of the exhaust camshaft 14 while avoiding the valve timing control device 21. ing. The lower end of the front cover 11 is located near the upper part of the accessory drive chains 26 and 27, specifically, a V formed by the accessory drive chains 26 and 27 when viewed from the axial direction of the crankshaft 12.
It extends so as to face from above in the valley of the character. A pipe 33 for connecting a blow-by gas hose (not shown) is fixed to the upper end of the bulging portion 31. The other end of the blow-by gas hose connected to this pipe is
In this embodiment, it is connected to an air cleaner. The pipe 33 constitutes a blow-by gas discharge port according to the present invention.

As shown in FIG. 3, a baffle plate 34 is integrally formed inside the bulging portion 31 of the front cover 11 so as to partition a space S inside the bulging portion 31 in the vertical direction in FIG. At the same time, a partition plate 35 for partitioning the space S from the auxiliary machine room 16 is fixed.
The partition plate 35 is formed so as to cover the opening inside the bulging portion 31 over the entire area, and a blow-by gas inlet 36 is formed at a lower end (an end on the crank chamber side). Is provided with an oil discharge port 37 below. The partition plate 35 has two sub-baffle plates 3 so as to further divide the two spaces partitioned by the baffle plate 34 into two spaces.
8, 39 are fixed. By providing a plurality of baffle plates 34, 38, and 39 in this manner, a maze-shaped blow-by gas passage is formed in a space S surrounded by the front cover 11 and the partition plate 35 so as to extend in the vertical direction.

The oil separator 32 thus formed
According to the blow-by gas reduction device provided with the oil separator 3, when the engine is operating, the intake negative pressure is reduced via the blow-by gas hose and the pipe 33 at the upper end of the front cover.
2, the blow-by gas in the auxiliary equipment chamber 16 and the oil particles which are mist-like and float in the auxiliary equipment chamber 16 are sucked into the oil separator 32 from the blow-by gas inlet 36. That is, during the operation of the engine, the mist-shaped oil scattered in the crank chamber and the valve operating cam chamber 18 is sucked into the oil separator 32 from the auxiliary machine chamber 16 together with the blow-by gas.

In the oil separator 32, the blow-by gas and the oil particles flow upward from below in a maze-like blow-by gas passage formed by three baffle plates 34, 38, and 39. At this time, since the oil particles rise against the gravity in the oil separator 32, the moving speed decreases relatively to the blow-by gas, and the baffle plates and the oil separator 32 move.
On the inner wall surface (the inner surface of the front cover 11 and the inner surface of the partition plate 35). When the oil particles adhere to the wall portion in the oil separator 32, the blow-by gas and the oil are separated.

The blow-by gas is supplied to the oil separator 32
After flowing through the inside to the upper end, it is sucked into the air cleaner through the pipe 33 and the blow-by gas hose. The oil flows down in the oil separator 32, returns to the auxiliary machine chamber 16 from the oil discharge port 37 at the lower end, and further flows along the inner surface of the front cover 11 to the oil storage section below the crank chamber.

Therefore, according to the blow-by gas reducing device, the oil separator 32 is formed to extend in the axial direction of the cylinder at one side of the engine.
Despite adopting a structure in which the oil separator 32 is provided in the engine, the overall height of the engine can be reduced. Also, since the oil separator 32 is formed using the front cover 11, the oil separator 3
The capacity of the oil separator 32 can be increased as compared with a structure in which the oil separator 2 is formed separately from the front cover 11 and disposed inside the front cover 11. In addition, since the oil separator 32 can separate oil using gravity, the efficiency of separating oil increases.

In this embodiment, accessory drive chains 26 and 27 for transmitting the rotation of the crankshaft 12 to the alternator 24 and the compressor 25 are provided so as to form a V-shape when viewed from the axis of the crankshaft. Accordingly, the lower end of the oil separator 32 can be formed so as to face from above the valley of the V-shape, and the length of the oil separator 32 in the vertical direction can be increased to increase the capacity.

In the above-described embodiment, an example in which one timing chain 15 is used to transmit the rotation of the crankshaft 12 to the intake and exhaust camshafts 13 and 14 has been described. A transmission means for transmitting rotation by a gear, or a transmission means for transmitting rotation by using a gear and a chain may be employed.

[0023]

As described above, according to the present invention, the oil separator can be formed so as to extend in the axial direction of the cylinder at one side of the engine. , The overall height of the engine can be reduced.

According to the second aspect of the present invention, since the oil separator can be formed by using the front cover, the oil separator is formed separately from the front cover and disposed inside the front cover. As a result, a large-capacity oil separator can be formed without increasing the size of the engine. In addition, the oil separator can efficiently separate oil using gravity.

[Brief description of the drawings]

FIG. 1 is a front view of a front cover used in a blow-by gas returning device according to the present invention.

FIG. 2 is a rear view of the front cover.

FIG. 3 is a sectional view of the front cover and the head cover taken along line III-III in FIG. 1;

FIG. 4 is a sectional view showing a conventional oil separator.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... Front cover, 12 ... Crankshaft, 16 ... Accessory room, 18 ... Valve operating chamber, 31 ... Swelling part, 32 ... Oil separator, 33 ... Pipe, 34, 38, 39 ... Baffle plate, 35 ... Partition Plate, 36: blow-by gas inlet, 37: oil outlet.

Claims (2)

[Claims] 1. A blow-by gas reducing device for an engine having an oil separator for separating blow-by gas and oil, wherein an auxiliary side communicating with a crank chamber and a valve operating cam chamber is provided on one side of the engine in the axial direction of a crank shaft. A machine room is formed by the engine and the front cover, a part of the front cover is bulged in a direction away from the cylinder, the oil separator is provided inside the bulged portion, and a blow-by gas inlet of the oil separator is provided. A blow-by gas reducing device for an engine, wherein an oil discharge port is opened in the auxiliary machine room. 2. The blow-by gas reducing device for an engine according to claim 1, wherein a baffle plate is integrally formed on an inner surface of a bulging portion of the front cover.
A partition plate for partitioning the space inside the bulging portion from the auxiliary equipment room is fixed to the front cover, and a blow-by gas inlet and an oil discharge port are formed at a lower end of the partition plate. A blow-by gas reducing device for an engine, wherein a blow-by gas discharge port is formed.