JPH0229214Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention is based on a so-called double overhead camshaft (DOHC) system in which intake and exhaust camshafts are provided in the cylinder heads of the first and second banks. This invention relates to an oil separator for a V-type engine.

(Prior art) In recent years, the layout of the intake system has been considered to increase intake efficiency by taking into account intake resistance, dynamic effects of intake, etc. An intake device is interposed in the cylinder head, intake and exhaust camshafts are arranged on the inner and outer sides of the cylinder head of each bank, and the intake manifold of the intake device is connected to the inner side of each bank. There is something I did.

By the way, blow-by gas is generally returned to the intake system in engines, and in that case, since the blow-by gas contains oil, the oil (oil mist) is removed by passing it through an oil separator. After reducing the amount, it is returned to the intake system. When the blow-by gas is returned to the intake system, it is customary to provide an oil separate section above the camshaft within the head cover above the cylinder head, as described in Japanese Patent Application Laid-Open No. 143308/1983.

(Problem to be solved by the invention) However, if the same method is applied to the V-type engine as described above, the overall height of the engine will increase, and there will be a risk of interference with the intake system on the inner side of each bank, and the oil There is a problem in that the layout of the intake system is restricted in order to prevent interference between the separate part and the intake device.

SUMMARY OF THE INVENTION An object of the present invention is to provide an oil separator for a V-type engine in which an oil separator can be arranged without hindering the freedom of layout of an intake system.

(Means for Solving the Problems) In the present invention, an intake device having a surge tank and an intake manifold is disposed above the first and second banks, and the air intake system is arranged on the inner and outer sides of the cylinder head of each bank. An intake camshaft and an exhaust camshaft are respectively arranged on the sides, the intake device is arranged above the intake camshaft in a position close to the head cover, and the intake manifold of the intake device is connected to the inner side of each bank. In the V-type engine, the intake manifold has one end connected to the side of the surge tank on the second bank side, and extends outward so as to be close to the head cover above the intake camshaft of the second bank, and extends below the surge tank. a first intake manifold which is bent to the side of the first bank and whose other end is connected to the inner side of the first bank; and one end which is connected to the side of the surge tank on the first bank side and which is connected above the intake camshaft of the first bank. and a second intake manifold that extends outward to be close to the head cover of the cylinder head and is bent below the surge tank, and the other end is connected to the inside of the second bank, and the cylinder head of at least one bank is It is characterized in that an oil separate part is formed in the head cover above the exhaust camshaft located outwardly so as to protrude upward.

(Function) Since the oil separate part is formed to protrude upward in the head cover above the exhaust camshaft located outside the cylinder head of at least one bank, the intake system can be installed without increasing the overall height of the engine. This prevents interference between the head cover and the head cover.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

The DOHC type V-type engine 1 shown in FIGS. Oil pan 5 is installed. A crankshaft 7 is provided in a crankcase 6 made up of the oil pan 5 and the lower part of the cylinder block 4.

Cylinder heads 8 of the first and second banks 2, 3 are hermetically sealed to the upper surface of the cylinder block 4,
9, an intake camshaft (only 11A is shown) and exhaust camshafts 10B, 11B are provided symmetrically when viewed from the crankshaft axis direction, and in each bank 2, 3, the intake camshaft is on the inner side, and the intake camshaft is on the outer side. Exhaust camshafts 10B and 11B are disposed on both sides, respectively.
Furthermore, two of the four camshafts 10B, 11A are linked to the crankshaft 7 at their front ends, thereby allowing the camshafts 10B, 11A and the crankshaft 7 to rotate simultaneously. . That is, a timing belt 15 is wound around timing pulleys 12 and 13 fixed to the front ends of the camshafts 10B and 11A, and a crank pulley 14 fixed near the front end of the crankshaft 7. 16, 17, and 18 are idlers.

In addition, in the cylinder block 4, the first bank 2 has odd numbered cylinders, and the second bank 3 has even numbered cylinders, and the pistons of each cylinder are connected to connecting rods (not shown). Crankshaft 7
are connected in order from the front. Thus, the cylinders of one bank are located between the cylinders of the other bank in the axial direction of the crankshaft 7, and the cylinders of the second bank 3 are arranged in parallel with the cylinders of the first bank 2.
The timing pulleys 12 and 13 are spaced apart from each other in the axial direction of the crankshaft 7.

In the second bank 3, a gear 21 is installed between the timing pulley 13 of the intake camshaft 11A and the nearest bearing (not shown), and another gear 22 meshing with the gear 21 is connected to the exhaust camshaft 11B. attached to the front end of the As a result, the exhaust camshaft 11B is rotationally driven via the intake camshaft 11A.

On the other hand, in the first bank 2, gears (not shown) that mesh with each other are fixed to the rear ends of both camshafts similarly to the second bank 3, and the intake camshaft is rotationally driven via the exhaust camshaft 10B. It is becoming more and more like this.

Furthermore, head covers 25, 26 are provided on the upper surfaces of the cylinder heads 8, 9 of the first and second banks 2, 3.
An oil separate part 27 is formed in the head cover 26 for the second bank 3 at a position corresponding to the upper part of the exhaust camshaft 11B so as to protrude upward.

As shown in FIGS. 3, 4, and 5, the oil separate section 27 is connected to the exhaust camshaft Y.
A cover plate 29 is attached to the lower side of the outer partition wall 28 that projects into the camshaft chamber from the head cover 26 along the line 1B through a sealing material (not shown), and opens into the camshaft chamber through an opening 27a on one side. are doing. Oil separate section 27
The connection port 27b is a communication path 30 through which fresh air is introduced.
It is connected to the air cleaner 31 via. In addition, the oil separate section 27 has a large volume and is provided with a plurality of baffle plates 32, so that when blow-by gas flows out into the atmosphere through the oil separate section 27 during high-load operation,
This ensures that the oil is separated.

Also, the cylinder block 4 between both banks 2 and 3
Another oil separate section 33 is provided at the top. Connection port 3 of this oil separate part 33
3a is connected to the intake passage 36 downstream of the throttle valve 37 via a communication passage 35 through which a check valve (not shown) is attached and through which blow-by gas flows out. The check valve allows only flow from the oil separate portion 33 to the intake passage 36.

Note that the blow-by gas is from the cylinder block 4.
The oil is guided from inside the crankcase 6 into the oil separate section 33 through a passage 37 provided in the center of the oil. Further, the camshaft chambers in the head covers 25, 26 of both banks 2, 3 communicate with each other through passages 38, 39 provided in the cylinder block 4 via an oil separate section 33.

40 is a distributor, a worm wheel 41 is fixed to the lower end of its rotating shaft (not shown), and this worm wheel 41 is connected to a worm gear 42 fixed to the end of the exhaust camshaft 11B in the second bank 3. It meshes with. The worm wheel 41 is connected to the exhaust camshaft 11B.
The worm gear 42 meshes with the worm gear 42 at a portion outside the axis of the worm gear 42 . Accordingly, the exhaust camshaft 1
The rotation of 1B drives the distributor 40.

Further, an intake device 47 is disposed above both banks 2 and 3, and a surge tank 45 is disposed above oil separate section 33 between both banks 2 and 3. surge tank 45
is connected to the inner side of each bank 2, 3 via intake manifolds 46A, 46B, and is configured to supply air taken in from the air cleaner 31 to each cylinder. The intake manifolds 46A, 46B have one end connected to the side of the surge tank 45 on the second bank 3 side, and extend outward so as to be close to the head cover 26 above the intake camshaft 11A of the second bank 3. A first intake manifold 46A that is bent downward from the surge tank 45 and whose other end is connected to the inside of the first bank 2, and the first bank 2 of the surge tank 45.
One end is connected to the side of the surge tank 4, and the surge tank 4 extends outward so as to be close to the head cover 25 above the intake camshaft 10A of the first bank 2.
5 and a second intake manifold 46B which is bent downward and whose other end is connected to the inner side of the second bank 3.

With the above configuration, during low-load operation with a small amount of blow-by gas, blow-by gas is distributed to the oil separate section 33, the check valve, and the communication passage 35.
The air is returned to the intake passage 36 downstream of the throttle valve 37, and is combusted together with the intake air-fuel mixture in a combustion chamber (not shown). At this time, due to the outflow of blow-by gas, the top surface of the cylinder head 9 and the head cover 2
Since the pressure inside the camshaft chamber surrounded by
The oil is introduced through the oil separate section 27 to achieve pressure balance.

On the other hand, during high-load operation, the amount of blow-by gas increases and the pressure inside the camshaft chamber increases, so blow-by gas flows out not only from the oil separate section 33 side but also from the oil separate section 27 side. In this case, the blow-by gas flowing out through the oil separate section 27 will be released to the atmosphere from the air cleaner 31, but since the oil separate section 27 has a large capacity and is equipped with a large number of buff-full plates 32, Since the oil is effectively separated, there is no problem that the element of the air cleaner 31 gets wet, and almost no oil is released into the atmosphere.

Incidentally, in FIG. 1, the intake manifolds 46A and 46B do not appear to extend much above the head covers 25 and 26 above the intake camshaft; Considering, depending on the engine, the intake manifold 46A, 46B
may need to be made longer. In such a case, it is necessary to arrange the intake camshaft above the intake camshaft and close to the head cover in order to make the entire engine including the intake system 47 more compact without increasing its height. Therefore, in the present invention, an oil separate section 27 is provided in the head cover 26 above the exhaust camshaft 11B located on the outer side of the second bank 3, so that the oil separation section 27 can be installed without increasing the height of the entire engine.
Intake device 47 located on the inner side of banks 2 and 3
and interference with the head cover 26 is reliably prevented,
This is done so that the degree of freedom in layout of the intake device 47 is not obstructed.

Furthermore, during high-load operation, the length of the communication passage 30 through which blow-by gas flows to the air cleaner 31 side may become longer than when an oil separate section is provided on the intake camshaft 11A side. It is sufficient for the communication passage 30 to have a predetermined length, but even if it is longer than the predetermined length, oil mist that is not completely trapped by the oil separate section 27 will adhere to the inner wall surface of the communication passage 30 and enter the intake system. There is no inconvenience because the function of making it difficult to clean and reducing oil consumption is not impaired.

In the above embodiment, since the insides of the head covers 25 and 26 communicate with each other via the oil separate part 33, the oil separate part 27 is provided only in the head cover 26 of the second bank 3, but both the head covers 25 and 26 communicate with each other through the oil separate part 33. 26, and although one timing belt is used in this example, a structure with two timing belts may also be used.

(Effects of the invention) As described above, in the present invention, the oil separate part is formed in the head cover above the exhaust camshaft located outside the cylinder head of at least one bank so as to protrude upward.
It is now possible to reliably prevent interference between the intake system and the head cover without increasing the overall height of the engine, and the necessary oil separation effect against blow-by gas can be achieved without hindering the layout freedom of the intake system. It becomes possible to provide an oil separate section for obtaining oil.

[Brief explanation of the drawing]

The drawings show an embodiment of the invention, and FIG.
A front view of a DOHC type V-type engine, Fig. 2 is a partially sectional plan view, Figs. 3 and 4 are a plan sectional view and a side sectional view of the oil separate section, and Fig. 5 is an oil It is an explanatory view of a separation effect. 1... V-type engine, 2, 3... Bank, 8,
9... Cylinder head, 11A... Intake camshaft, 10B, 11B... Exhaust camshaft, 25, 26... Head cover, 27, 33...
...Oil separate section, 46A, 46B...Intake manifold, 47...Intake device.

Claims (1)

[Claims for Utility Model Registration] An intake device having a surge tank and an intake manifold is disposed above the first and second banks, and intake and In a V-type engine, each exhaust camshaft is disposed, the intake device is disposed above the intake camshaft in a position close to the head cover, and the intake manifold of the intake device is connected to the inner side of each bank, The intake manifold has one end connected to the second bank side of the surge tank, protrudes outward so as to be close to the head cover above the intake camshaft of the second bank, and is bent below the surge tank. a first intake manifold whose end is connected to the inner side of the first bank; and a first intake manifold whose one end is connected to the side of the surge tank on the first bank side;
and a second intake manifold that extends outward so as to be close to the head cover above the intake camshaft of the bank, is bent below the surge tank, and has the other end connected to the inside of the second bank, and at least An oil separator for a V-type engine, characterized in that an oil separator portion is formed in a head cover above an exhaust camshaft located outside a cylinder head of one bank and projects upwardly.