JP2676300B2 - Exhaust gas recirculation system for turbocharged engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas recirculation system for a supercharged engine.

[0002]

2. Description of the Related Art In an engine of an automobile to which a supercharger is not attached, a part of the exhaust gas discharged from the exhaust passage of the engine is returned to the intake passage and exhaust gas recirculation (EGR) for reducing NOx is performed. Has been done.

[0003]

However, in an engine with a supercharger, the supply air compressed by a compressor is cooled by an intercooler and supplied to the intake side of the engine. Therefore, if a part of the exhaust gas is returned to the air supply side, the exhaust gas deteriorates the corrosion and performance of the intercooler, and the temperature of the air supply is significantly increased to deteriorate fuel efficiency.

It is an object of the present invention to provide an exhaust gas recirculation system for a supercharged engine that solves the above-mentioned problems.

[0005]

The gist of the present invention for achieving the above object is to provide two superchargers each including an exhaust turbine and a compressor rotated by the exhaust turbine, and the two superchargers. Two exhaust passages respectively connected to each exhaust turbine of the feeder, two supply passages connecting each compressor of the two superchargers and an upstream side of one intercooler, and a downstream side of the intercooler One intake passage connected to the intake side of the engine, and one of the upstream intake passages of the intercooler and the exhaust side of the engine are connected via an exhaust valve, and this exhaust valve is connected. The intercooler upstream side of the air supply passage and the air supply passage on the downstream side of the intercooler are connected by a bypass passage, and the bypass passage and the air supply passage on the intercooler upstream side are connected by a direction switching valve. Which are connected to.

Further, one supercharger consisting of an exhaust turbine and a compressor rotated by the exhaust turbine, and two superchargers each having a diffuser portion formed on the discharge side of the compressor of the supercharger and partitioned by a partition plate. It comprises a discharge port, two air supply passages connecting these two discharge ports to the intercooler upstream side, and one air supply passage connecting the downstream side of the intercooler and the intake side of the engine.
The diffuser portion and the exhaust side of the engine are connected via an exhaust valve, and one of the two air supply passages on the upstream side of the intercooler and the air supply passage on the downstream side of the intercooler are connected by a bypass passage. This bypass passage and the air supply passage on the upstream side of the intercooler are connected via a direction switching valve.

[0007]

With the above structure, when the exhaust gas recirculation is not performed, the entire supply air from the supercharger passing through the two air supply passages is supplied to the intake side of the engine through the intercooler to perform the exhaust gas recirculation. Occasionally, one of the two air supply passages passes through an intercooler, and a portion of the exhaust gas of the other air supply passage merges with an exhaust gas, passes through a bypass passage, and joins with the air supply passing through the intercooler. Supply to the intake side of the engine.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a concrete embodiment of claim 1. In FIG. 1, 1 is an engine, 2 is an intake manifold on the intake side of the engine 1, and 3 is an exhaust manifold on the exhaust side of the engine 1.

Numerals 4 and 5 are two superchargers, which are composed of exhaust turbines 4a and 5a and compressors 4b and 5b which are rotated by the exhaust turbines 4a and 5a. Exhaust turbines 4a, 5 of the two superchargers 4, 5
Each of a is connected to the exhaust manifold 3 via exhaust passages 16 and 17.

The compressors 4b and 5b of the two superchargers 4 and 5 are connected to the upstream side of one intercooler 7 via two air supply passages 6a and 6b. Further, the downstream side of the intercooler 7 and the intake manifold 2 of the engine 1 are connected by one air supply passage 8.

One of the air supply passages 6b connected to the upstream side of the interkura 7 and the exhaust manifold 3 of the engine 1 are connected by a pipe 9 equipped with an exhaust valve 10.
Intercooler 7 of air supply passage 6b to which this pipe 9 is connected
Of the intercooler 7 and the air supply passage 8 on the downstream side of the intercooler 7 are connected by a bypass passage 11, and the bypass passage 11 and the air supply passage 6b on the upstream side of the intercooler 7 are connected via a direction switching valve 12. Has been done.

Reference numeral 13 is a rotation sensor of the engine 1, and
Reference numeral 4 is a load sensor. The detection signals of the rotation sensor 13 and the load sensor 14 are input to the control device 15, and the control device 15 opens and closes the exhaust valve 10 and switches the direction switching valve 12.

In the above configuration, exhaust gas recirculation (hereinafter referred to as E
When not performing GR), the exhaust valve 10 is closed, the direction switching valve 12 closes the bypass passage 11, and the intake passage 6b is switched to communicate with the intercooler 7.

As a result, as shown in FIG. 1, all of the air supplied from the two superchargers 4, 5 through the two air supply passages 6a, 6b passes through the intercooler 7 to form one air supply passage 8. It is supplied to the intake manifold 2 of the engine 1 via.

When the EGR is performed, the controller 15
The exhaust valve 10 is opened in response to the command signal from the directional control valve 12 to open the bypass passage 11, and the intake passage 6 is opened.
b is switched so as to close the flow to the intercooler 7.

As a result, as shown in FIG. 2, the supply air from one supercharger 4 is taken out through the intercooler 7 into the one supply passage 8 by the supply passage 6a, and is supplied to the other supercharger 5. A part of the exhaust gas is introduced into the air supply passage 6b through the pipe 9, and the air supply passage 6 into which a part of the exhaust gas is introduced.
The supply air that passes through b is merged with the supply air that has passed through the intercooler 7 through the bypass passage 11 and is supplied to the intake manifold 2 of the engine 1 after being merged at the supply passage 8.

At this time, the supply air into which a part of the exhaust gas that has passed through the bypass passage 11 is introduced does not pass through the intercooler 7, so that the temperature thereof rises. As a result, the temperature is lowered and supplied to the engine 1.

3 to 6 show a concrete embodiment of claim 2. In FIG. 3, 1 is an engine, 2 is an intake manifold on the intake side of the engine 1, and 3 is an exhaust manifold on the exhaust side of the engine 1.

Reference numeral 4 denotes one supercharger, which is an exhaust turbine 4
a and a compressor 4b rotated by the exhaust turbine 4a. The exhaust turbine 4 a of the one supercharger 4 is connected to the exhaust manifold 3 via an exhaust passage 16.

As shown in FIG. 5, on the discharge side of the compressor 4b of the supercharger 4, two discharge ports 26a, 26 are formed by forming a diffuser portion 24 and partitioning by a partition wall 20.
b, the two outlets 26a, 26b and the upstream side of the intercooler 7 are connected via two air supply passages 6a, 6b, and the intake manifold 2 on the downstream side of the intercooler 7 and the intake side of the engine 1 is connected. And one air supply passage 8
Connected with.

The exhaust passage 16 and the pipe 21 are connected to the diffuser portion 24, and an exhaust valve 22 is provided in the pipe 21. The diffuser portion 24 to which the pipe 21 is connected has a slit 23 which is a fixed diaphragm.

Furthermore, the air supply passage 8 on the upstream side of the intercooler 7 and the air supply passage 8 on the downstream side of the intercooler 7 in the air supply passage 6b.
And the bypass passage 11 are connected to each other, and the bypass passage 11
And the air supply passage 6b on the upstream side of the intercooler 7 are connected via a direction switching valve 25.

In the above structure, when the EGR is not performed, the exhaust valve 22 is closed and the direction switching valve 25
Closes the bypass passage 11, and the intake passage 6b is switched to communicate with the intercooler 7.

As a result, as shown in FIG. 3, the supercharger 4
Through the two air supply passages 6a and 6b, all are supplied to the intake manifold 2 of the engine 1 through the intercooler 7 and one air supply passage 8.

When performing EGR, the exhaust valve 22 is opened by the command signal of the control device 15 shown in FIG. 1, and the direction switching valve 25 opens the bypass passage 11,
The intake passage 6b is switched so as to close the flow to the intercooler 7.

On the other hand, the diffuser portion 24 is the partition wall 20.
The air supply is divided into two systems. Therefore, the air supply is divided by the partition wall 20 and introduced into the two air supply passages 6a and 6b. As shown in FIG. 5, a part of the exhaust gas is introduced into the diffuser portion 24 through the opening of the exhaust valve 22 as shown in FIG. This diffuser section 24 is shown in FIG.
Since the exhaust pressure is lower than the exhaust pressure, the exhaust gas is mixed into the supply air, and the supply air on the side where the exhaust gas is mixed is introduced into the supply passage 6b by the partition wall 20.

The supply air introduced into the supply air passage 6a passes through the intercooler 7 and is taken out to one supply air passage 8, and the supply air mixed with the exhaust gas introduced into the supply air passage 6b is supplied by the bypass passage 11. The supply air that has passed through the intercooler 7 and the supply air are merged in the supply passage 8 and are supplied to the intake manifold 2 of the engine 1.

[0028]

As described above, according to the present invention, the air supply system from the supercharger has two systems, all of which are passed through the intercooler to be supplied to the intake side of the engine, and one of the air supply systems is exhausted. Since a part of the gas is mixed and merged with the air supply of the other air supply system that has passed through the intercooler via a bypass passage bypassing the intercooler, it is possible to supply it to the intake side of the engine. In an engine equipped with an engine, it has an effect of enabling exhaust gas recirculation without allowing the exhaust gas to pass through the intercooler and without significantly increasing the supply air temperature.

[Brief description of the drawings]

FIG. 1 is a system diagram of the present invention in a state where exhaust gas recirculation is not performed.

FIG. 2 is a system diagram of the present invention in a state where exhaust gas recirculation is being performed.

FIG. 3 is a system diagram of the present invention in a state where exhaust gas recirculation is not performed.

FIG. 4 is a system diagram of the present invention in a state where exhaust gas recirculation is being performed.

FIG. 5 is a sectional view of a compressor portion of the supercharger.

FIG. 6 is a diagram showing air supply, exhaust, and pressure of a diffuser section in the compressor section of FIG.

[Explanation of symbols]

 1 engine 2 intake manifold 3 exhaust manifold 4 supercharger 4a exhaust turbine 4b compressor 5 supercharger 5a exhaust turbine 5b compressor 6a air supply passage 6b air supply passage 7 intercooler 8 air supply passage 9 piping 10 exhaust valve 11 bypass passage 12 direction Switching valve 16 Exhaust passage 17 Exhaust passage 20 Partition wall 21 Piping 22 Exhaust valve 24 Diffuser part 25 Directional switching valve

Claims (2)

(57) [Claims] 1. A supercharger comprising an exhaust turbine and a compressor rotated by the exhaust turbine,
Two exhaust passages respectively connected to the exhaust turbines of the two superchargers; two air supply passages connecting each compressor of the two superchargers and the upstream side of one intercooler; It is composed of one air supply passage connecting the downstream side of the intercooler and the intake side of the engine, and one of the air supply passages on the upstream side of the intercooler and the exhaust side of the engine are connected via an exhaust valve, and this exhaust gas An intercooler upstream side of the air supply passage to which the valve is connected and an air supply passage on the intercooler downstream side are connected by a bypass passage, and the bypass passage and the air supply passage on the intercooler upstream side are connected via a direction switching valve. An exhaust gas recirculation system for a supercharged engine characterized by the above. 2. A supercharger comprising an exhaust turbine and a compressor rotated by the exhaust turbine,
A diffuser portion is formed on the discharge side of the compressor of the supercharger, and two discharge ports are defined by a partition plate, two air supply passages connecting the two discharge ports to the upstream side of the intercooler, and the intercooler. It consists of one air supply passage connecting the downstream side and the intake side of the engine, connects the diffuser part and the exhaust side of the engine through an exhaust valve, and connects one of the two air supply passages on the upstream side of the intercooler. A supercharger characterized in that a supply passage and a supply passage downstream of the intercooler are connected by a bypass passage, and the bypass passage and a supply passage upstream of the intercooler are connected via a direction switching valve. Engine exhaust gas recirculation device.