JPH0533647A - V-type internal combustion engine - Google Patents

Abstract

PURPOSE:To secure a space so as to make a thermostat housing installable in front of an engine as well as to reduce each overhang in both symmetrical cross directions. CONSTITUTION:A timing chain 11 is set up so as to directly drive only an intake side camshaft 6 at the bank inside, and further it is pushed to the inside by a sprocket 21 of a water pump 19. With this constitution, a thermostat housing 24 is set up in a space being produced between the water pump 19 and an exhaust side camshaft 7. This thermostat housing 24 is formed as facing the front as one body with a cylinder head.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a V-type internal combustion engine,
In particular, it relates to improvement of the formation position of the thermostat housing in a water-cooled V-type internal combustion engine equipped with a DOHC type valve operating mechanism.

[0002]

2. Description of the Related Art In a water-cooled cooling system for an internal combustion engine,
As is well known, a thermostat valve can switch between a flow passage that passes through the radiator side and a bypass flow passage that does not pass through the radiator, but the thermostat valve is generally pre-assembled as an independent unit and cooled. The thermostat valve is housed and used in a thermostat housing having a water inlet or a cooling water outlet.

The thermostat housing is often formed separately from the cylinder block and the cylinder head, and is generally provided in the middle of the inlet tube or the like. For example, Japanese Utility Model Laid-Open No. 61-78228 discloses a conventional example in which a thermostat housing is formed integrally with a cylinder block. In this example, the thermostat housing is formed on the side surface of the cylinder block so as to face obliquely downward. ing. This is because there is a chain mechanism or a belt mechanism for driving the valve train at the front end of the engine, and it is difficult to secure the installation space for the thermostat housing.

[0004]

However, in the structure in which the thermostat housing is provided on the side surface of the engine or in the middle of the inlet tube as in the above-mentioned conventional case, the thermostat housing occupies a relatively large space,
There was a problem of hindering the miniaturization of the engine. In addition, when it is arranged on the side surface of the engine, it is hidden under the intake and exhaust system, and there is a drawback that maintainability is extremely poor when replacing the thermostat valve.

[0005]

A V-type internal combustion engine according to the present invention is a V-type internal combustion engine in which a pair of cam shafts is provided in each cylinder head of left and right banks. It is driven by a timing chain wound between the cam sprocket at the front end and the crank sprocket, and a pair of cam shafts on the outside of the bank are linked to the cam shafts on the inside of the adjacent banks via another chain mechanism or gear mechanism. And, a water pump is arranged between the cam sprocket and the crank sprocket of one bank, the sprocket is meshed with the back side of the timing chain, and further, the water pump and the camshaft outside the bank above it. A part of the front end of the engine surrounded by and a timing chain It is characterized in that a thermostat housing which is formed integrally with the cylinder head.

[0006]

In the above structure, the camshaft outside the bank is located outside the timing chain connecting the left and right cam sprockets and the crank sprocket. Also, the layout is such that the timing chain is pushed inward by the water pump sprocket, and a space for the thermostat housing is secured between the water pump and the cam shaft above it. That is, the thermostat housing formed integrally with the cylinder head is arranged at the front end portion of the engine without significantly protruding to the outside.

[0007]

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

FIG. 2 is a sectional view showing the structure of the front end portion of the V-type 6-cylinder internal combustion engine according to the present invention. This V-type internal combustion engine, as shown in FIG. The cylinder heads 2 are fixed to the upper surfaces of the banks, respectively, and a chain case rear 3 formed in a plate shape by, for example, aluminum die casting is attached so as to cover the front surfaces of the cylinder block 1 and the cylinder head 2. ing. A cover-shaped chain case front 4 is further attached to the front surface of the chain case rear 3 to form a chain chamber 5 therebetween. FIG. 1 shows the internal structure of the chain chamber 5 with the chain case front 4 removed in such a V-type internal combustion engine. Further, FIG. 4 shows the front shapes of the cylinder block 1 and the cylinder head 2 from which the chain case rear 3 is removed.

This V-type internal combustion engine has cylinder heads 2
Has a DOHC valve operating mechanism including a pair of cam shafts, and an intake side cam shaft 6 is arranged inside the bank and an exhaust side cam shaft 7 is arranged outside the bank. The layout of the timing chain that drives the valve operating mechanism will be described with reference to FIG.
A crank sprocket 9 is provided on the crankshaft 8 below the cylinder block 1, and a substantially triangular shape is formed between the first cam sprocket 10 provided on the intake side camshafts 6 of the left and right banks and the crank sprocket 9. One timing chain 11 is wound around. A second cam sprocket 12 having a small diameter is provided on the intake camshaft 6 so as to overlap the first cam sprocket 10, and the cam sprocket 13 of the exhaust camshaft 7 and each second cam sprocket 12 adjacent thereto are provided.
The sub-timing chains 14 are respectively wound between and. That is, the intake side camshaft 6 inside the bank is driven by the crankshaft 8 rotating in the direction of arrow A in FIG.
The exhaust side camshaft 7 on the outside of the bank is interlocked via the shaft 4. Between the intake side camshaft 6 and the first and second cam sprockets 10 and 12, there is provided an actuator 18 of a variable valve timing mechanism that changes the phase of both by a predetermined amount (for example, about 10 ° CA) by hydraulic pressure. It is interposed (see FIG. 2).

A lower end is rotatably supported between a first cam sprocket 10 and a crank sprocket 9 on the left side of the drawing on the loose side of the timing chain 11, and a hydraulic chain tensioner 15 is provided at the upper end. The chain guide 16 provided is provided so that appropriate tension is applied to the timing chain 11. A chain guide 17 is attached between the pair of left and right first cam sprockets 10 to slightly press the timing chain 11 toward the inner peripheral side.

On the other hand, a water pump 19 is arranged between the first cam sprocket 10 and the crank sprocket 9 on the right side of the drawing, which is the tension side of the timing chain 11, and the water pump mounted on the drive shaft 20 thereof. The pump sprocket 21 meshes with the rear surface side of the timing chain 11, that is, the outer peripheral side. The water pump sprocket 21 is located approximately in the middle of the first cam sprocket 10 and the crank sprocket 9, and
1 is pushed inward. Chain guides 22 and 23 are provided above and below the water pump sprocket 21, respectively.

The side portion of the chain case rear 3 is partially recessed in a shape surrounded by the water pump 19, the exhaust side cam sprocket 13 above the water pump 19, and the timing chain 11. A thermostat housing 24, which will be described later, is arranged here.

As shown in FIGS. 2 and 6, the water pump 19 has a pump housing 26 mounted on the opening of the chain case rear 3 with bolts 25 and an impeller 27 fixed to the tip of the drive shaft 20. The drive shaft 20 is rotatably supported by a pump housing 26 via a bearing 28, and a mechanical seal 29 is provided between the impeller 27 and the pump housing 26. .. The impeller 27 is provided in the involute chamber 3 recessed in the front surface of the cylinder block 1.
It is located at 0. This involute chamber 30 is shown in FIG.
As shown in FIG. 6, the cylinder block 1 has a cooling water introducing portion 31 extending to the center thereof, and the cooling water introducing portion 31 communicates with the water jackets 32 and 33 of the left and right banks. In FIG. 6, the cooling water inlets 34 and 35 that open to the seating surface of the cylinder head 2 are shown in phantom lines, and the cooling water is also introduced to the cylinder head 2 side through these cooling water inlets 34 and 35. It is like this. Further, between the involute chamber 30 and the water jacket 33 of the cylinder block 1, the upper surface, that is, the cylinder head 2 is provided.
The cooling water passage portion 36 is formed so that the side is open,
The cooling water passage portion 36 and the involute chamber 30 communicate with each other through a circular opening portion 36a facing the central portion of the impeller 27.

As shown in FIG. 2, the cooling water passage portion 36 has a thermostat housing 2 on the cylinder head 2 side.
4 It communicates with the inside. As shown in FIGS. 2 and 4, the thermostat housing 24 is formed integrally with the cylinder head 2 on the front end surface of the cylinder head 2, specifically, below the exhaust side cam shaft 7, and faces the front. The opening is formed in a circular shape, and the flange portion 24a is formed on the peripheral edge of the opening. The tip of the bypass passage 37, which communicates with a cooling water outlet (not shown), opens at the bottom of the interior. This thermostat housing 2
4, an inlet tube 38 connected to a radiator (not shown) is attached by a bolt 39 (see FIG. 3), and the thermostat valve 4 laterally inserted in the thermostat housing 24 is provided.
0 is held between the inner peripheral side of the flange portion 24a.
The thermostat valve 40 is of a so-called bottom bypass type, and opens and closes between the cooling water passage portion 36 and the inlet tube 38, and at the same time, the cooling water passage portion 36.
The bypass passage 37 is opened and closed. That is, explaining the flow of the cooling water, the cooling water pumped by the water pump 19 is the water jackets 32 and 33 of the cylinder block 1 and the cylinder head 2.
Into the water jackets (not shown) from the front end side and flow toward the rear end portion of the engine. Then, the cooling water taken out from the cooling water outlet at the rear end of the engine by the external pipe is guided to the radiator and flows from the radiator into the cooling water passage portion 36 via the inlet tube 38 and the thermostat valve 40. , And then circulates again to the water pump 19. When the thermostat valve 40 is closed and the water temperature is low, the cooling water outlet at the rear end of the engine flows into the bypass passage 37 via the external pipe for bypass, and returns to the water pump 19 without passing through the radiator.

FIG. 3 shows the V-type internal combustion engine in a state in which it is assembled with various accessories and the like. As shown in FIG. 3, the inlet tube 38 attached to the thermostat housing 24 is the engine. It is bent to the side. In FIG. 3, reference numeral 41 is an alternator, 42 is a compressor for an air conditioner, and 4 is a compressor.
3 indicates an oil pump for power steering,
These are accessory belts 45, 4 by the crank pulley 44.
Driven via 6. Further, 47 is a cylinder head cover that covers the upper surface of the cylinder head 2, 48 is an intake manifold, 49 is an engine mount bracket, and 50 is an oil pan.

According to the configuration of this embodiment, the timing chain 11 is arranged relatively inside the front end face of the engine, and is secured between the exhaust side cam sprocket 13 and the water pump 19 outside the bank. The thermostat housing 24 is arranged on the front surface of the engine in such a manner that the space is effectively used. Therefore, the thermostat housing 2
4 can be formed so as not to project to the side surface of the engine, which is advantageous in downsizing the engine. In particular, it is possible to reduce the amount of protrusion of auxiliary machinery such as the alternator 41 mounted on the side surface of the engine as shown in FIG.

Further, since the thermostat housing 24 is provided close to the water pump 19 and the thermostat housing 24 is formed integrally with the cylinder head 2, the cooling water passage from the thermostat housing 24 to the water pump 19 is described above. Thus, the internal passage can be formed, and the external piping can be simplified. In particular, in this embodiment, since the water pump 19 is housed in the chain chamber 5, attempting to connect the external pipe to the water pump 19 causes a problem such as sealing with the chain case front 4, but the internal passage By doing so, problems such as this sealing can be avoided.

Further, since the thermostat housing 24 is formed so as to face forward on the front surface of the engine, it is very maintainable when replacing or inspecting the thermostat valve 40.

In the above embodiment, the exhaust side camshaft 7 is used.
Although the intake side camshaft 6 and the intake side camshaft 6 are interlocked via a chain mechanism, they may be interlocked via a gear mechanism.

[0020]

As is apparent from the above description, in the V-type internal combustion engine according to the present invention, the thermostat housing integrated with the cylinder head is arranged at the front end of the engine so as not to project to the side of the engine. Therefore, it is possible to reduce the outer dimensions of the engine including the auxiliary machinery, especially the lateral dimension which is a problem in the V-type internal combustion engine. Further, since the thermostat housing is located at the front end portion of the engine that is hard to be covered by the intake and exhaust systems, the maintainability when exchanging the thermostat valve is improved.

[Brief description of drawings]

FIG. 1 is a front view showing a configuration inside a chain chamber of a V-type internal combustion engine according to the present invention.

FIG. 2 is a sectional view of the front end of the V-type internal combustion engine according to the present invention.

FIG. 3 is a front view showing an assembled state in which accessories and the like are mounted on the V-type internal combustion engine.

FIG. 4 is a front view showing a configuration of front ends of a cylinder block and a cylinder head.

FIG. 5 is a front view showing a cylinder block together with a water pump.

6 is a cross-sectional view taken along the line BB of FIG.

[Explanation of symbols]

 3 ... Chain case rear 6 ... Intake side camshaft 7 ... Exhaust side camshaft 9 ... Crank sprocket 10 ... First cam sprocket 11 ... Timing chain 19 ... Water pump 21 ... Water pump sprocket 24 ... Thermostat housing

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kaoru Haga 1 791-5-791 Hibarigaoka, Zama City, Kanagawa Prefecture Nissan Techno Co., Ltd.

Claims (1)

Claim: What is claimed is: 1. A V-type internal combustion engine comprising a pair of cam shafts in each of the cylinder heads of the left and right banks, wherein a pair of cam shafts inside the bank is provided with a cam sprocket and a crank sprocket at the front end thereof. Driven by a timing chain wound between the two banks, the pair of cam shafts on the outside of the bank are interlocked with the cam shafts on the inside of the adjacent banks via another chain mechanism or gear mechanism, and the cams of one bank A water pump is arranged between the sprocket and the crank sprocket, and the sprocket is meshed with the back side of the timing chain, and further surrounded by the water pump, the camshaft outside the bank above it, and the timing chain. Integrated with the cylinder head at the front end of the engine V-type internal combustion engine, characterized in that a thermostat housing form.