JPH0571426A - Exhaust high pressurizing device for egr - Google Patents

Abstract

PURPOSE:To realize efficient EGR without making a compressor of a first turbosupercharger dirty due to exhaust gas by providing the compressor for intaking and compressing only exhaust gas, and merging together the compressed exhaust gas for EGR in an air supply tube of a first exhaust turbosupercharger for supercharging an engine. CONSTITUTION:In an exhaust high pressure device provided with a first exhaust turbosupercharger 40 for supercharging an engine, a second exhaust turbosupercharger 60 exclusive to EGR is disposed. A blower 61 of the second exhaust turbosupercharger is connected on an intake side thereof to a common exhaust tube 33. A discharge tube 70 is connected to an air supply tube 12 of an engine disposed on a discharge side of the blower of the first turbosupercharger, thus carrying out EGR.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an exhaust turbocharged internal combustion engine.

[0002]

2. Description of the Related Art EGR of a conventional exhaust gas turbocharged internal combustion engine
The configuration will be described with reference to FIG. FIG. 2 is a configuration diagram of an EGR of a conventional exhaust gas turbocharged internal combustion engine. 1 in the figure
Reference numeral 1 is an intake valve, 31 is an exhaust valve, 20 is a combustion chamber, and 32 is an exhaust pipe. A common exhaust pipe 33 is connected to all exhaust pipes of the engine. 41 is an exhaust turbine, and 34 is an exhaust turbine inlet pipe that connects the common exhaust pipe 33 and the exhaust inlet of the exhaust turbine 41. 42 is a supercharger and is connected to the exhaust turbine 41. Reference numeral 10 is an intake pipe, and the intake pipe of the supercharger 42 communicates with the atmosphere. An intake pipe 12 is connected to the discharge side of the supercharger 42. 35 is an EGR pipe, and the common exhaust pipe 33 is connected to the supercharger 4
It communicates with the two suction pipes 10.

The operation of the conventional example will be described. When the exhaust valve 31 is opened during engine operation, the burnt gas in the combustion chamber 20 passes through the exhaust pipe 32 and becomes exhaust gas, which collects from each cylinder to the common exhaust pipe 33.
It flows from the common exhaust pipe 33 through the exhaust turbine inlet pipe 34 into the exhaust turbine 41, and is discharged to the atmosphere by turning. The supercharger 42 is driven by the exhaust turbine 41 and sucks the atmosphere from the suction pipe 10 and a part of the exhaust gas in the common exhaust pipe 33 through the EGR pipe 35 together with the air and compresses it to a supercharging pressure to supply the air. Exhale to 12. In a normal operating state, the pressure in the intake pipe 12 that is supercharged is higher than the pressure in the common exhaust pipe 33, and the exhaust gas from the common exhaust pipe 33 cannot be directly supplied to the intake pipe 12.

[0004]

When performing EGR, the supercharging pressure is higher than the exhaust pressure.
Therefore, if added to the intake side of the supercharger, the supercharger will be contaminated with exhaust gas and the performance will deteriorate. Also, since exhaust gas with a pressure higher than atmospheric pressure is expanded to the intake pressure of the supercharger and compressed by the supercharger, the power consumption of the supercharger increases and the efficiency of the exhaust turbocharger decreases. And deteriorate the engine performance. It is an object of the present invention to provide a second exhaust turbocharger that compresses only exhaust gas in an exhaust turbocharged engine to add air to the engine.

[0005]

A suction pipe is opened to a common exhaust pipe of an engine outside a conventionally equipped first exhaust turbocharger, and a discharge pipe of the intake pipe is provided on a discharge side of the first exhaust turbocharger. And a second exhaust turbocharger connected to the air supply pipe of the engine.

[0006]

With the second exhaust turbocharger, a part of the exhaust gas of the engine is compressed to a pressure equal to the pressure in the intake pipe and added to the intake air of the engine.
Perform GR.

[0007]

Embodiment An embodiment according to the present invention will be described with reference to FIG. FIG. 2 is an explanatory diagram of an embodiment according to the present invention. In the figure, 11 is an intake valve, 12 is an intake pipe, 20 is a combustion chamber, 31
Is an exhaust valve, 32 is an exhaust pipe, 33 is a common exhaust pipe, 34 is an exhaust inlet pipe of an exhaust turbocharger, 41 is a first exhaust turbine, and 42 is a first supercharger, which is a well-known exhaust turbocharger engine. Since it is an element, explanation is omitted. A second exhaust turbine 62 for EGR is connected to the common exhaust pipe 33. 61 is EG
A second supercharger for R is coaxially connected to the second exhaust turbine 62, and the air supply pipe is a common exhaust pipe 33 via an exhaust cooler.
Is in communication with. Reference numeral 60 denotes a second exhaust turbo supercharger for EGR, which includes a second exhaust turbine 62 and a second supercharger 61. An exhaust cooler 43 is provided on the intake side of the EGR second supercharger 61. An EGR pipe 70 communicates the discharge side of the second EGR supercharger 61 with the air supply pipe 12.

Next, the operation of the above embodiment will be described. The exhaust pipe 44 supplies the exhaust gas discharged from the unillustrated cylinders to the common exhaust pipe 33 to the second turbine 62. The second exhaust turbine 62 is rotated by the exhaust gas and rotates the second supercharger 61. The second supercharger 61 compresses a part of the exhaust gas of the common exhaust pipe 33 through the exhaust cooler 43 so as to equalize the pressure of the intake pipe 12 and discharges it to the EGR pipe 70. The EGR pipe 70 joins the compressed exhaust gas on the discharge side of the exhaust turbocharger 40 and sends the exhaust gas to the air supply pipe 12. The air supply pipe 12 sends the air discharged from the first exhaust turbocharger 40 and the exhaust gas discharged from the EGR pipe 70 together to the intake port of the engine. Therefore, a part of the exhaust gas is mixed with the intake air of the engine and the EGR is performed.

[0009]

Since part of the exhaust gas of the engine is supplied to the supercharging pressure, the exhaust gas can be mixed with the supply gas to perform EGR. Since the exhaust gas does not flow into the supercharger 42 of the first exhaust turbocharger 40, the exhaust gas does not become dirty and the performance does not deteriorate.
The EGR second supercharger 61 sucks the high-pressure exhaust gas, which is also the power source of the second exhaust turbine 62, as it is, so that the compression is small and the power consumption is small. Also, the second supercharger 61
Since the exhaust gas sucked by is cooled by the exhaust cooler and the temperature is low, the power consumption is further reduced. Therefore, the present invention provides only the exhaust gas for EGR in the exhaust turbocharged engine with the second supercharger 6
It is possible to provide an efficient device that performs EGR in addition to the discharge side of the first supercharger 42 by compressing at 1.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment according to the present invention.

FIG. 2 is a block diagram of a conventional EGR.

[Explanation of symbols]

40 ... 1st exhaust turbo supercharger, 60 ... EGR 2nd exhaust turbo supercharger, 61 ... EGR compressor (2nd supercharger), 12
... Air supply pipe, 33 ... Common exhaust pipe, 70 ... EGR pipe.

Claims (1)

[Claims] 1. An internal combustion engine in which supercharging is performed by a first exhaust turbocharger (40), a second exhaust turbocharger (6)
The intake port of the blower (61) of (0) opens to the common exhaust pipe (33) of the internal combustion engine, and its discharge side merges with the discharge side of the blower (42) of the first exhaust turbocharger to the engine. E
An EGR exhaust pressure increasing device having a second exhaust turbocharger (60) for performing GR.