JPS6349070B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention recirculates part of the exhaust gas to the intake system in a V-type internal combustion engine to suppress an excessive rise in the combustion temperature of the air-fuel mixture in the combustion chamber, thereby reducing the risk of air pollution. This invention relates to an exhaust gas recirculation device that prevents the generation of nitrogen oxides.

Conventionally, as such a device, an exhaust gas recirculation path is formed in the wall of the intake manifold of an internal combustion engine, and an exhaust gas recirculation pipe extending from the exhaust system of the engine is connected to the upstream end of this exhaust gas recirculation path. It is known that the downstream end is opened to the distribution chamber of the intake manifold, and a part of the engine exhaust gas is returned to the distribution chamber of the intake manifold through an exhaust gas recirculation pipe and an exhaust gas recirculation path. By the way, in general, if the temperature of the recirculated exhaust gas is too high, the fuel will be carbonized when it comes into contact with the fuel adhering to various parts of the distribution chamber. In order to lower the temperature, the exhaust gas recirculation pipe is made long or heat radiation fins are attached around the pipe, but such exhaust gas recirculation pipes are an obstacle to making the recirculation device more compact.
Therefore, particularly in V-type internal combustion engines, there is a problem in that it is difficult to install the intake manifold in the narrow V-shaped space between the two left and right cylinder rows.

The present invention has a structure in which the recirculated exhaust gas in the exhaust gas recirculation path can be effectively cooled without causing the above-mentioned problems, and the cooling means can also be used to simultaneously heat the distribution chamber of the intake manifold. It is an object of the present invention to provide a simple and compact exhaust gas recirculation device for a V-type internal combustion engine.

In order to achieve the above object, the present invention provides an intake manifold between the cylinder heads of two left and right cylinder rows each having a plurality of cylinders and arranged in a V-shape. A plurality of branch passages extend from the left and right sides of the distribution chamber toward the cylinder heads of the left and right cylinder rows, respectively, and a plurality of branch passages extend from the exhaust system to the upstream end of the exhaust gas recirculation passage formed in the wall of the intake manifold. In an exhaust gas recirculation device for a V-type internal combustion engine, the exhaust gas recirculation pipe is connected to the exhaust gas recirculation pipe and the downstream end of the recirculation pipe is opened to the distribution chamber.
an intermediate portion extending substantially parallel to the crankshaft below the distribution chamber; an upstream portion opening at one side of the upper portion of the intake manifold and descending from the upstream end to one end of the intermediate portion; a downstream portion rising from the end to the downstream end opening at the top of the distribution chamber; The present invention is characterized in that a pair of left and right water jackets are formed which are sandwiched between them, and both water jackets are communicated with a cooling water jacket of the engine.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, E indicates a V-type six-cylinder internal combustion engine having two left and right cylinder rows C ₁ and C ₂ arranged in a V-shape. Cylinder block 1 of this engine
The upper surface has a horizontal plane 1a in the center and roof-shaped slopes 1b ₁ and 1b ₂ on both sides, and cylinder rows C ₁ and C ₂ are formed on these slopes 1b ₁ and 1b ₂ .
The upper ends of each of the three cylinders 2 are opened, and the cylinder heads 3 of the cylinder rows C ₁ and C ₂ are respectively joined. Further, an intake manifold M is joined to the horizontal surface 1a, and both left and right side surfaces of this intake manifold M are joined to the inner end surfaces of the left and right cylinder heads 3, respectively. Furthermore, a carburetor Ca is attached to the top surface of the intake manifold M.

Pistons 5 that move up and down within each cylinder 2 are connected to a common crankshaft 4 supported on the lower surface of the cylinder block 1 via connecting rods 6, respectively.

Each cylinder head 3 has a main combustion chamber 7 defined by a piston 5 and a torch nozzle 9 in the chamber 7.
, a main intake port 10 and an exhaust port 14 respectively open to the main combustion chamber 7 , and a sub-intake port 1 opened to the sub-combustion chamber 8 .
1 is formed, the main intake port 10 is formed by the main intake valve 12, and the sub-intake port 11 is formed by the sub-intake valve 1.
3, and the exhaust port 14 is opened and closed by an exhaust valve 15, respectively. The spark plug 16 screwed onto the cylinder head 3 has its electrode facing the sub-combustion chamber 8.

The carburetor Ca has a lean mixture, that is, a main mixture;
A rich mixture, ie, a sub-air mixture, can be generated at the same time, and these main and sub-air mixtures are distributed through the intake manifold M to the main and sub-intake ports 10 and 11, respectively.

In each cylinder 2, when the main and auxiliary intake valves 12 and 13 are opened by the suction stroke of the piston 5, the main air-fuel mixture passes through the main intake port 10 into the main combustion chamber 7, and the auxiliary air-fuel mixture flows into the auxiliary combustion chamber 7. Intake port 11
They are respectively supplied to the sub-combustion chamber 8 through the auxiliary combustion chamber 8. Then, in the next compression stroke, the rich sub-air mixture in the sub-combustion chamber 8 is ignited by the spark discharge from the ignition plug 16, and the flame is injected into the main combustion chamber 7 through the torch nozzle 9. The main mixture is ignited and burned.
As a result, combustion of a mixture with a lean overall air-fuel ratio becomes possible. In this way, the piston 5 moves to the expansion stroke, and when the exhaust valve 15 is opened in the next exhaust stroke,
Exhaust gas is discharged to the exhaust port 14 and further to the exhaust pipe 17.

Next, the intake manifold M for the main and sub-air mixtures is
The route in will be explained. FIG. 2 is a plan view of the intake manifold M. In this drawing, the upper side corresponds to the left side of the engine E, that is, the cylinder row C ₁ side, the lower side corresponds to the right side, that is, the cylinder row C ₂ side, and the left side corresponds to the engine E. The front and right side correspond to the rear of the same. Therefore, the longitudinal direction of the intake manifold M corresponds to the axial direction of the crankshaft 4 of the engine E.

The upper end surface of this intake manifold M, that is, the carburetor mounting surface 18 has a hole that communicates with the primary and secondary bores that generate the main mixture of the carburetor Ca.
The secondary and secondary main inlets 19, 19', and the sub-inlet 20 which communicates with the sub-bore that generates the sub-air mixture of the carburetor Ca are arranged in the longitudinal direction of the engine E and open (second, (See Figure 8), both main entrances 19,
A common main distribution chamber 21 communicating therewith is provided directly below the sub-inlet 19', and a primary sub-distribution chamber 22 communicating therewith is provided immediately below the sub-inlet 20.
The main distribution chamber 21 consists of an upper chamber 21a and a lower chamber 21b, which has a larger volume and communicates with it via a through hole _{23 .} Main intake port 10
Three main branch paths 24 are connected to each other.

Therefore, the main air-fuel mixture generated in the carburetor Ca flows into the main distribution chamber 21 from the main inlet 19 or 19'.
The air flows into the chamber 21, where it is distributed into a plurality of main branch passages 24, and is sucked into each main intake port 10 as described above.

The primary sub-distribution chamber 22 is the upper chamber 21 of the main distribution chamber 21.
a, lined up adjacent to the rear, and 2 from the left and right side walls.
A primary sub-branch path 25 for books extends and communicates with a pair of secondary sub-distribution chambers 22' adjacent to each other on both left and right sides of the upper chamber 21a of the main distribution chamber 21. Further, three secondary sub-branch passages 25' extending from each outer wall of each secondary sub-distribution chamber 22' extend to the sub-intake ports 11 of each cylinder row C ₁ and C ₂ .

Therefore, the sub-air mixture generated in the carburetor Ca flows into the primary sub-distribution chamber 22 from the sub-inlet 20, and flows from the chamber 22 into the left and right two sub-distribution chambers 22 through the two primary sub-branch passages 25. It is distributed to the secondary sub-distribution chamber 22', and in the chamber 22' it is distributed to a plurality of secondary sub-branch passages 25', and is sucked into each sub-intake port 11 as described above.

As shown in FIG. 1, an exhaust outlet hole 26 is provided on one side of the exhaust pipe 17, and an exhaust gas introduction hole 27 is provided on the upper rear surface of the intake manifold M. 28 connects.

As shown in FIGS. 2, 5, 6, and 8, there is a hole in the wall of the intake manifold M between the exhaust gas introduction hole 27 and the exhaust gas outlet hole 29 that opens in the front wall of the upper chamber 21a of the main distribution chamber 21. An exhaust gas recirculation path 30 is formed that communicates with the exhaust gas recirculation path 30 . Therefore, the exhaust gas introduction hole 27 is the upstream end of the exhaust gas recirculation path 30, and the exhaust gas outlet hole 29 is the downstream end thereof.

The exhaust gas recirculation path 30 has an intermediate portion 30b that cuts vertically almost horizontally directly below the main distribution chamber 21 and is approximately parallel to the crankshaft 4, and an intermediate portion 30b that extends from the exhaust gas introduction hole 27.
It consists of an upstream section 30a that descends toward the rear end, and a downstream section 30c that ascends toward the exhaust outlet hole 29 from the front end of the intermediate section 30b.
0a is an opening 3 on the top surface of the intake manifold M in the middle
1 and 31', and an exhaust gas recirculation amount control valve 32 is attached to the intake manifold M so as to connect between the openings 31 and 31'. On the other hand, as shown in FIGS. 2 and 8, a baffle plate 33 facing the exhaust outlet hole 29 is provided upright in the upper chamber 21a of the main distribution chamber 21.

Therefore, while the engine E is operating, a part of the exhaust gas flowing through the exhaust pipe 17 is transferred from the exhaust outlet hole 26 to the exhaust gas recirculation pipe 2.
8, flows into the exhaust gas recirculation path 30 from the exhaust introduction hole 27, is controlled by the control valve 32 to a flow rate that is suitable for the operating state of the engine, and then flows out from the exhaust outlet hole 29 to the upper chamber 21a of the main distribution chamber 21. do. Upper room 2
The exhaust gas flowing into 1a immediately collides with the baffle plate 33 and is divided into left and right sides, where it mixes with the main mixture passing through the main distribution chamber 21, and further moves to the lower chamber 21b where it is mixed with the main mixture more deeply. During this time, since the exhaust gas is still at a higher temperature than the main mixture, the main mixture is directly heated to promote its vaporization. In this way, the exhaust gas is distributed to each main intake port 10 by the main branch passage 24 together with the main air-fuel mixture, and then recirculated to the main combustion chamber 7.
In this way, the recirculated exhaust gas plays the role of suppressing an excessive rise in the combustion temperature during combustion of the air-fuel mixture and preventing the generation of nitrogen oxides.

The engine E and the intake manifold M each have water jackets Je and Jm, and the flow paths of water to these water jackets will be explained with reference to FIG.

Extends from the outlet Ro of radiator R and connects to the same inlet Ri
A water pump P, a water jacket Je of the internal combustion engine E, and a water jacket Jm of the intake manifold M are sequentially inserted in series into the main water passage 34 returning to the main water passage 34 from the upstream side. The water pump P is mechanically driven by the engine E and sucks cooling water from the outlet Ro of the radiator R.
This is designed to be pumped into the water jacket Je. A thermostat T is provided at the outlet Jmo of the water jacket Jm of the intake manifold M, which opens when the water temperature in the water jacket exceeds a certain value.

Also, the water jacket Jm of the intake manifold M
From the first and second bypass waterways 35 ₁ , 35 ₂
are connected to the main waterway 34 between the outlet Ro of the radiator R and the water pump P, and the second bypass waterway ₃₅₂ is connected to the heat exchanger H for heating the vehicle.
is interposed.

Furthermore, the intake manifold M includes a temperature-sensitive switch Sf that senses when the water temperature in the water jacket Jm rises above a certain value and operates the electric fan F for cooling the radiator R, and a temperature-sensitive switch Sf that operates in response to changes in the water temperature. A water temperature sensor S that operates a water temperature gauge (not shown) is attached. In the figure, Jei and Jeo indicate the inlet and outlet of the water jacket Je, and Jmi indicates the inlet of the water jacket Jm.

When the engine E is operated at a low temperature, the thermostat T closes and closes the outlet Jmo of the water jacket Jm of the intake manifold M, so that the water pumped by the water pump P first flows through the engine. The water is sent to the water jacket Je of E, passes through this, moves to the water jacket Jm of the intake manifold M, and is then divided into the first and second bypass waterways 35 ₁ and 35 ₂ , thus bypassing the radiator R. They merge at the downstream main waterway 34 and are sucked into the water pump P.
Repeat the above cycle. Therefore, the water in the main waterway 34 does not pass through the radiator R and has little chance of radiating heat, so the temperature can quickly rise as the engine E generates heat, and the temperature can rise quickly to warm up the engine E and the intake manifold M. promotes temperature rise. Then water jacket
When the water temperature of Jm rises above the specified value and the thermostat T opens, most of the water that has passed through the water jacket Jm exits from the outlet Jmo with low flow resistance and enters the inlet Ri of the radiator R. , the heat is radiated by passing through the radiator R, but a portion of it follows the path to the first and second bypass waterways 35 ₁ and 35 ₂ as before. moreover,
The water temperature in the water jacket Jm rises and the temperature-sensitive switch is activated.
When Sf closes, electric fan F operates to promote heat dissipation from radiator R. In this way, the total amount of water pumped from the water pump P is always kept in the water jacket.
The engine E and the intake manifold M are controlled to an appropriate temperature by passing through Je and Jm sequentially.

Next, the configuration of the water jackets Je and Jm will be explained.

First, as shown in FIG. 1, the water jacket Je of the engine E includes a lower jacket 36 formed on the cylinder block 1 so as to surround the cylinder 2 in each cylinder row C ₁ and C ₂ , and a main and sub-intake port 1.
0, 11, an upper jacket 37 formed on the cylinder head 3 so as to surround the exhaust port 14, the ignition plug 16, etc., and both jackets 36,
37 are communicated with each other through a communication hole 38 passing through the joint surfaces of the cylinder block 1 and the cylinder head 3. Although not shown in Figure 1, the lower jacket 3
The inlet Jei for the water jacket Je is provided at the bottom of the water jacket 6. The upper jacket 37 then communicates with an outlet Jeo that opens on the horizontal surface 1a of the cylinder block 1 via a passage 39 that returns to the upper part of the cylinder block 1, and this outlet Jeo also connects to the inlet of the water jacket Jm that opens on the lower surface of the intake manifold M. Communicate directly to Jmi. Therefore, the water pumped from the water pump P first reaches the lower jacket 36.
After cooling the area around the cylinder 2, it passes through the communication hole 38 to the upper jacket 37, cooling the area around the exhaust valve 15 and the spark plug 16, and
After heating the surroundings of the main and auxiliary intake ports 10 and 11, the water flows into the water jacket Je of the intake manifold M through the passage 39 and the outlet and inlets Jeo and Jmi in sequence.

As shown in FIGS. 2 and 3, the outlet Jeo of the water jacket Je and the inlet Jmi of the water jacket Jm are each formed with a flat cross section, and are connected to the left cylinder row.
Three cylinders are provided on the _C1 side on the left side of each joint surface between the cylinder block 1 and the intake manifold M, and three cylinders on the right cylinder row _C2 side are provided on the right side of each joint surface.

The water jacket Jm of the intake manifold M is connected to the lower chamber 2 of the main distribution chamber 21, as shown in FIGS.
1b, and a pair of left and right upper jackets 40 that extend in the front-back direction across the main distribution chamber 21;
It consists of a lower jacket 41 that communicates with the corresponding upper jacket 40 through It opens at the bottom surface of the jacket 40.
In addition, the upper and lower jackets 40 on each side of the left and right sides,
41 communicate with each other via a communication jacket 44 around the main branch path 24, as shown in FIG.
As shown in FIG. 8, the rear jacket 42 surrounds the downstream portion 30c of the exhaust gas recirculation path 30 and
An annular jacket 42a is provided that passes directly below the sub-distribution chamber 22 and immediately after the lower chamber 21b of the main distribution chamber 21. As shown in FIGS. 4 and 8, the outlet Jmo is provided at the upper part of the rear jacket 42, and the thermostat T is mounted on the upper surface of the intake manifold M where the outlet opens.

As shown in FIG. 4, the temperature-sensitive switch Sf and the water temperature sensor S are respectively installed in mounting holes 45 and 46 formed in the rear end surface of the intake manifold M so as to sense the water temperature in the rear jacket 42.
In addition, the first and second bypass waterways 35 ₁ , 3
Connecting pipes 47 ₁ and 47 ₂ at the upstream end of 5 ₂ are provided to protrude from the rear end face thereof. Note that 48 is an air bleeder mounting hole.

Then, the engine E is cooled and the intake manifold M
The hot water flowing into each inlet Jmi of the water jacket Jm flows into the left and right upper jackets 40, and then half of it flows into the lower jacket 41 on the same side through the through hole 43. In this way, each jacket 40,4
The hot water flowing into the rear jackets 42
During the flow, the lower chamber 2 of the main distribution chamber 21
1b and the main branch passage 24 to promote vaporization of the main air-fuel mixture passing through them,
The intermediate portion 30b of the exhaust gas recirculation path 30 is cooled to lower the temperature of the exhaust gas passing through it. The cooling water flowing through the upper and lower jackets 40, 41 joins at the rear jacket 42, cooling the upstream portion 30a of the exhaust gas recirculation path 30, and flowing through the annular jacket 42a to the rear surface of the lower chamber 21b of the main distribution chamber 21. and heats the lower surface of the primary sub-distribution chamber 22 to promote vaporization of the main mixture and sub-air mixture passing through them, and at the same time cools the upstream portion 30a of the exhaust gas recirculation passage 30 to pass through therein. Reduces exhaust gas temperature. The main air-fuel mixture and the sub-air mixture whose vaporization was promoted in this way were sucked into the main combustion chamber 7 and the sub-combustion chamber 8 of the engine E, where they were able to burn well, and the temperature was appropriately lowered. When the exhaust gas is sent to the main distribution chamber 21, it does not carbonize the fuel adhering to various parts of the chamber 21.

The present invention can be applied not only to a torch-ignited internal combustion engine having main and auxiliary combustion chambers as described above, but also to a normal type engine. In this case, in the intake manifold M, the auxiliary Branch road 25'
The route leading to is no longer necessary. Therefore, the main distribution chamber 21 in the embodiment described above corresponds to the distribution chamber of the present invention, and the main branch path 24 corresponds to the branch path of the present invention.

As described above, according to the present invention, an intake manifold is disposed between the cylinder heads of two left and right cylinder rows each having a plurality of cylinders and arranged in a V-shape, and the intake manifold is distributed. A plurality of branch passages extend from the left and right sides of the chamber toward the cylinder heads of the left and right cylinder rows, and the exhaust gas extending from the exhaust system is connected to the upstream end of the exhaust gas recirculation passage formed in the wall of the intake manifold. In an exhaust gas recirculation device for a V-type internal combustion engine, in which a recirculation pipe is connected and a downstream end of the recirculation path is opened to the distribution chamber, the exhaust gas recirculation path is connected to an intermediate portion extending substantially parallel to the crankshaft below the distribution chamber. an upstream section that opens at one side of the upper part of the intake manifold and descends from the upstream end to one end of the intermediate section, and an upstream section that rises from the other end of the intermediate section and opens at the upper part of the distribution chamber. and a downstream part reaching the downstream end, and a pair of left and right water jackets are formed in the wall of the intake manifold directly below the distribution chamber, sandwiching the middle part of the exhaust gas recirculation passage from both left and right sides. Since the water jacket was connected to the cooling water jacket of the engine, the exhaust gas recirculation path was arranged so that the above-mentioned upstream, intermediate, and downstream parts of the exhaust gas recirculation path detoured in a roughly U-shape below the distribution chamber. Furthermore, the intermediate portion is effectively cooled from both the left and right sides by the pair of left and right water jackets, so that the exhaust gas flowing through the exhaust gas recirculation path is effectively cooled. It is possible to sufficiently lower the temperature and prevent carbonization of adhering fuel in the distribution chamber, and as a result, it is possible to form the exhaust downstream pipe installed outside to be extra long, or to attach heat dissipation fins to the outer periphery. There is no need to do this, and the entire device can be configured compactly.
The intake manifold including the exhaust gas recirculation path can be easily arranged even in the narrow V-shaped space between the left and right cylinder rows. In particular, since the middle part of the exhaust gas recirculation passage that crosses the lower part of the distribution chamber is arranged approximately parallel to the crankshaft, due to the structure of the V-type engine, there are a plurality of branch passages on the left and right sides of the distribution chamber. Although the exhaust gas recirculation passage extends, the exhaust gas recirculation passage can be easily formed in the intake manifold without being obstructed by these branch passages, and its workability is good. Furthermore, as mentioned above, the left and right water jackets, which function as cooling means for the intermediate portion of the exhaust gas recirculation path, are located in the intake manifold directly below the distribution chamber, and also function as heating means for the air-fuel mixture flowing through the distribution chamber. As a result, the air-fuel mixture can be efficiently heated, and distribution efficiency from the distribution chamber to each branch path can be improved, and the water jacket can be cooled and
By being able to serve as both heating means, the structure of the water channel in the intake manifold can be simplified accordingly.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional front view of a V-type six-cylinder internal combustion engine equipped with the device of the present invention, Fig. 2 is a plan view of the intake manifold of the engine, Fig. 3 is a bottom view thereof, and Fig. 4 is a rear view thereof. Figure 5 is a sectional view taken along the - line in Figure 2;
The figure is a sectional view taken along the line in the same figure, Figure 7 is a sectional view taken along the line in the same figure, Figure 8 is a sectional view taken along the line in the same figure, Figure 9 is a sectional view taken along the line in the same figure, and Figure 10 is a cooling water circuit diagram. It is. Ca... Carburetor, C ₁ ... Cylinder row (left), C ₂ ...
...Cylinder row (right), E...Internal combustion engine, Je...Engine water jacket, Jm...Intake manifold water jacket, M...Intake manifold, 2...
Cylinder, 7...Main combustion chamber, 8...Sub-combustion chamber, 2
1... Main distribution chamber as a distribution chamber, 22... Primary sub-distribution chamber, 22'... Secondary sub-distribution chamber, 27... Exhaust gas introduction hole as upstream end, 28... Exhaust gas recirculation pipe, 2
9... Exhaust outlet hole as downstream end, 30... Exhaust gas recirculation path, 30a... Upstream section, 30b... Intermediate section,
30c...downstream section, 40...upper jacket, 4
1... Lower jacket, 42... Rear jacket, 42a... Annular jacket, 44... Communication jacket.

Claims (1)

[Claims] 1. Each cylinder 2 has a plurality of cylinders 2 and is connected to each other by V.
Two cylinder rows C ₁ , C ₂ on the left and right arranged in a letter shape
Intake manifold M between cylinder heads 3 and 3 of
and the left and right cylinder rows from both the left and right sides of the distribution chamber 21 of the intake manifold M.
A plurality of branch passages 24 _. . . _, 24 . In an exhaust gas recirculation system for a V-type internal combustion engine, in which an exhaust gas recirculation pipe 28 extending from the system is connected and a downstream end 29 of the recirculation path 30 is opened to the distribution chamber 21, the exhaust gas recirculation path 30
an intermediate portion 30b extending substantially parallel to the crankshaft 4 below the distribution chamber 21, and an upstream portion that descends from the upstream end 27 opening on one side of the upper portion of the intake manifold M to one end of the intermediate portion 30b. Part 30
a, and a downstream portion 30c that rises from the other end of the intermediate portion 30b and reaches the downstream end 29 that opens into the upper portion 21a of the distribution chamber 21. Distribution room 21
Directly below the intermediate portion 30b of the exhaust gas recirculation path 30
A pair of left and right water jackets 4 sandwiching the
1, 41, and both water jackets 41, 41 are communicated with a cooling water jacket Je of the engine. 2. In what is stated in claim 1,
The internal combustion engine has a sub-combustion chamber 8 in its cylinder 2 that electrically ignites a rich sub-air mixture to generate a flame.
and a main combustion chamber 7 that burns a lean main air-fuel mixture with the flame, and the intake manifold M carries the main air-fuel mixture generated by the carburetor Ca into the main combustion chamber 7. a main distribution chamber 21 serving as the distribution chamber which distributes the mixture to the sub-combustion chamber 8; It has a water jacket 42a communicating with the cooling water jacket Je of the engine, and this water jacket 42a
An exhaust gas recirculation device for a V-type internal combustion engine, in which the exhaust gas recirculation path 30 is disposed below. 3 In what is stated in claim 1,
The pair of left and right water jackets 41, 41 are an exhaust gas recirculation device for a V-type internal combustion engine, and extend over substantially the entire length of the intermediate portion 30b of the exhaust gas recirculation path 30.