JPH0232857Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an exhaust gas recirculation device for a V-type engine, and specifically relates to a structure for forming an EGR passage for a surge tank.

(Prior art) Conventionally, a V-type engine has been equipped with a surge tank in its intake system, and the independent intake passages connected to each cylinder are once collected by this surge tank, and this surge tank is effectively connected to each bank. There is a known structure that is formed independently of each other (see Japanese Utility Model Application Publication No. 129063/1983).

When exhaust gas is recirculated to the surge tank configured as described above, the exhaust gas must be recirculated evenly to each cylinder with good distribution. However, when the intake inlet is opened at one end of the surge tank in the direction of the output shaft, the EGR passage is connected from the side opposite to the intake inlet of the surge tank to supply exhaust gas due to its relationship with the exhaust passage, etc. In this way, with respect to the flow of intake air from the intake inlet to each cylinder, exhaust gas is supplied to the downstream part, and exhaust gas is supplied only to the cylinders near the opening of the EGR passage. reflux takes place and its distribution is poor, making it impossible to obtain a sufficient NOx suppression effect and potentially affecting driveability.

Also, for the above reasons, if the EGR passage is provided so as to bypass the outside of the surge tank and connect to the intake inlet side, distribution performance will be improved, but this
This requires space for piping the EGR passage, and is accompanied by layout difficulties in arranging various equipment for the entire engine. In particular, with V-type engines, there is a requirement to reduce the overall height of the engine, so it is not desirable to place the EGR passage above the surge tank (an independent intake passage is connected to the side), and because there is relatively little space available. One part is the front part of the surge tank (the side opposite to the intake inlet), and if a connection opening is made in this part, there will be a problem in distribution as described above.

(Purpose of the invention) In view of the above circumstances, the present invention was designed to ensure distribution of exhaust gas recirculation, prevent the piping of the EGR passage from protruding outside, and make effective use of space to make the entire engine compact. The object of the present invention is to provide an exhaust gas recirculation device for a V-type engine.

(Structure of the device) The exhaust gas recirculation device of the present invention is one in which the inside of the surge tank is formed into separate chambers corresponding to the left and right banks by a partition wall. EGR running along
The system is characterized in that a passage is provided and the EGR passage opens into each separation chamber in the surge tank near the intake inlet.

(Effect of the invention) According to the invention, the EGR passage is formed to extend from the side opposite to the intake inlet of the surge tank to the intake inlet along the wall inside the surge tank, and each By opening into the separation chamber, the exhaust gas is recirculated to the upstream part of the intake flow, improving distribution to each cylinder and ensuring emission performance, and the piping of the EGR passage is exposed to the outside. Because there is no exhaust gas recirculation system, the layout is easy and can be easily formed, and the space can be used effectively in V-type engines where space around the engine is limited, making it possible to obtain a compact exhaust gas recirculation device with excellent performance. It is.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.
Figure 1 is a vertical cross-sectional front view of the main parts of the V-type engine, Figure 2
The figure is a plan view of the main parts, and in FIG. 2, the left side is the front of the engine and the right side is the rear.

A six-cylinder V-type engine 1 has cylinder heads 3, 3 inclinedly disposed on the left and right sides of a cylinder block 2 at the lower center, forming a left bank 1A and a right bank 1B at an angle to each other.

The intake device that supplies intake air to each cylinder of the left and right banks 1A and 1B on both sides is
A surge tank 6 is provided at the upper part between 1B and 1B. This surge tank 6 and left and right banks 1
A, 1B cylinder head 3, 3 (intake port)
The independent intake passages 7a and 7b that connect the two intersect with each other below the surge tank 6. That is,
The upstream end of the first independent intake passage 7a whose downstream end is connected to the left bank 1A is connected to the right side of the surge tank 6, and the upstream end of the second independent intake passage 7b whose downstream end is connected to the right bank 1B. Surge tank 6 at the end
It is connected to the left side of the

The internal space of the surge tank 6 is divided into a first separation chamber 6a and a second separation chamber 6a and 2, which are separated from each other on the left and right sides by a partition wall 8 extending in the front-rear direction (parallel to the engine output shaft).
It is divided into a separation chamber 6b. 1st on the right
A first independent intake passage 7a connected to the left bank 1A communicates with the separation chamber 6a through a communication port 6c opened on the right side, and a second separation chamber 6b on the left side communicates with the first independent intake passage 7a, which is connected to the left bank 1A.
The right bank 1 is connected to the right bank 1 through the communication port 6d opened on the left side.
A second independent intake passage 7b connected to B is in communication with the second independent intake passage 7b. Further, at the rear end of the surge tank 6, an intake inlet 9 is provided in each of the separation chambers 6a and 6b.
a, 9b are opened, and these intake inlets 9a, 9b
are connected to upstream intake passages 10a and 10b, and are provided with throttle valves 11a and 11b, respectively.

On the other hand, in the exhaust gas recirculation device that recirculates exhaust gas from the exhaust system to the intake system, one end of an EGR passage 14 is connected to an exhaust manifold 13 connected to one bank 1B, and extracts the exhaust gas. this
The EGR passage 14 is provided with an EGR valve that opens/closes or measures exhaust gas recirculation. Applicable
The EGR valve 15 is attached to the front end of the surge tank 6, that is, on the side opposite to the intake ports 9a and 9b, and the EGR valve 15 and the exhaust manifold 13 are connected by an EGR pipe 16.

The EGR passage 14 passing through the EGR valve 15 communicates with an inner hole 17 formed inside the partition wall 8 from one end of the output shaft of the surge tank 6, and extends along the partition wall 8 toward the rear end. It is formed. Then, it branches to both sides in the vicinity of the intake inlet ports 9a and 9b, and both separation chambers 6 in the surge tank 6
Intake intake ports 9a and 9b at a and 6b, respectively
Supply ports 18a and 18b provided below the opening of
It is constructed with an opening.

In addition, in the figure, 19 is a fuel injection nozzle,
20 each indicates a cooling fan.

With the configuration as in the above embodiment, when the EGR valve 15 is open, the exhaust gas from the exhaust manifold 13 is transferred to the EGR pipe 16 of the EGR passage 14.
The fuel is guided from the side of the engine to the front of the engine, and is introduced into the inner hole 17 in the partition wall 8 through the EGR valve 15 installed at the front end of the surge tank 6.
At this time, the EGR pipe 16 and the EGR valve 15 are cooled by the cooling air generated by the rotation of the cooling fan 20 located in front of the engine, thereby protecting the EGR valve 15 and preventing clogging of the EGR passage 14.

Next, the exhaust gas that has passed through the EGR valve 15 passes through the EGR passage 14 formed by the inner hole 17 in the partition wall 8 of the surge tank 6, and proceeds to the rear end of the surge tank 6, where it is branched to both sides and connected to each supply. Mouth 18a, 18
b into the separation chambers 6a, 6b on both sides. The exhaust gas introduced into each of the separation chambers 6a, 6b mixes with the flow of intake air from the intake ports 9a, 9b, flows down, and is evenly supplied to each cylinder with good distribution.

In the above embodiment, the EGR valve 15 is installed at the front end of the surge tank 6, but if the space in front of the surge tank 6 is small, it may be installed in another space such as below the surge tank 6. It is.

Further, the EGR passage 14 for the surge tank 6 may be formed not only in the partition wall 8 but also in a wall facing from the opposite side of the intake inlet to the intake inlet.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional front view of a main part of a V-type engine according to an embodiment of the present invention, and FIG. 2 is a plan view of the main part. 1...V-type engine, 1A, 1B...bank,
6...Surge tank, 6a, 6b...Separation chamber, 8
...Bulkhead, 9a, 9b...Intake inlet, 13...
Exhaust manifold, 14...EGR passage, 15...
...EGR valve, 16...EGR pipe, 17...inner hole,
18a, 18b... Supply port.

Claims (1)

[Scope of utility model registration request] In a V-type engine, a surge tank is arranged along the output shaft direction of the engine, and the inside of the surge tank is formed into substantially independent separation chambers for each left and right bank by a partition wall. For the surge tank having an intake inlet at one end, an EGR passage is provided which extends from the other end along the wall of the surge tank and opens into each separation chamber in the surge tank near the intake inlet. An exhaust gas recirculation device for a V-type engine, characterized in that it is provided with an exhaust gas recirculation device.