JP2011032880A - Exhaust gas recirculation device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress corrosion, breakage and wear of a compressor of a turbo supercharger without discharging foreign matter separated in a first intake duct 4 of an intake pipe to the outside of a vehicle. <P>SOLUTION: The intake pipe of an engine body includes the first intake duct 4 connected to an inlet 31 of the compressor, a second intake duct 5 connected to an outlet 33 of the compressor via a flow passage in an axial direction of an ejector 8, a foreign substance separating device separating the foreign matter from a fluid such as an EGR gas circulating in the first intake duct 4, the ejector 8, and a foreign matter discharging device with a slit 11 and a bypass flow passage 12. This configuration allows the foreign matter centrifugally-separated from the fluid by a swirling flow generated by a swirling flow generator 7 to bypass the compressor by the action of the ejector 8 and to be sucked by the ejector 8, and moreover, mixed in a high pressure fluid pressurized by the compressor, and then, introduced to the engine body through the second intake duct 5. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an exhaust gas recirculation device for an internal combustion engine that recirculates EGR gas, which is part of exhaust gas discharged from the internal combustion engine, to the internal combustion engine via an intake passage upstream of a compressor of a supercharger. In particular, the present invention relates to an exhaust gas recirculation device for an internal combustion engine that bypasses the compressor and the intercooler of the supercharger and guides them to the internal combustion engine without discharging the foreign material separated from the EGR gas by the foreign material separation device.

[Conventional technology]
Conventionally, an exhaust gas recirculation device (EGR gas) that recirculates a part of exhaust gas (EGR gas) discharged from an internal combustion engine (engine) such as a diesel engine equipped with a turbocharger (turbo supercharger) from an exhaust passage to an intake passage ( EGR system) is known.
In the case of this EGR system, only clean air that has passed through the air cleaner flows into the scroll chamber of the compressor housing of the turbocharger.
Here, the EGR gas contains a large amount of inert gas (water vapor, carbon dioxide, etc.) after combustion, but by using the EGR system, the combustion temperature is lowered and harmful gas contained in the exhaust gas. There is an effect that the generation amount of a substance (for example, nitrogen oxide: NOx) can be reduced.
Further, conventionally, a low pressure exhaust gas recirculation device (LPL-EGR system) that recirculates EGR gas from an exhaust passage downstream of a turbocharger turbine and a catalyst to an intake passage upstream of a compressor via an EGR gas pipe. ) Is also known.

[Conventional technical problems]
However, in the case of the LPL-EGR system, since the EGR gas is introduced from the EGR gas pipe into the intake passage upstream of the turbocharger compressor, foreign substances (carbon fine particles, water vapor, water vapor, etc.) contained in the EGR gas are introduced. Water droplets and icing, etc.) may also flow into the scroll chamber of the compressor housing along with the mixture of intake air and EGR gas.
Here, when foreign matter flows into the scroll chamber of the compressor housing of the turbocharger, there is a problem that the compressor impeller is damaged or worn.
Further, in the case of the LPL-EGR system, foreign substances contained in the EGR gas (including condensed water generated when the EGR gas is cooled by the air that has passed through the air cleaner) may flow into the scroll chamber of the compressor housing. There is.

Here, if the fuel contains a sulfur content, sulfurous acid gas (SO ₂ ) is generated from the sulfur content and discharged into the exhaust passage. Further, part of the sulfurous acid gas is further oxidized to produce sulfuric acid (SO ₄ ) and sulfuric anhydride (SO ₃ ). In this case, when the EGR gas is returned to the intake passage upstream of the compressor via the EGR gas pipe of the LPL-EGR system, the EGR gas containing these acidic substances flows into the intake passage. And if it cools with the air which passed the air cleaner, it will condense with the water vapor | steam contained in EGR gas, and will become strong acidic condensed water. If strongly acidic condensate adheres to and accumulates on a compressor made of a metal material such as an aluminum alloy, it may corrode equipment or intake pipes installed in the intake passage (such as a turbocharger compressor). There is.

Therefore, in order to quickly discharge the condensed water generated in the intake passage upstream of the compressor of the turbocharger to the outside of the intake pipe, the condensed water centrifuged from the EGR gas is collected, An LPL-EGR system in which a condensed water collecting mechanism for discharging is installed has been proposed (see, for example, Patent Document 1).
According to this condensed water collecting mechanism, the EGR gas is introduced from the low pressure EGR passage into the cylindrical portion of the casing provided so as to protrude laterally from the double pipe portion connected to the inlet of the compressor. The EGR gas introduced into the cylindrical portion from the low pressure EGR passage forms a swirling flow in the cylindrical portion, and condensed water contained in the EGR gas adheres to the inner surface of the cylindrical portion using the centrifugal force of the swirling flow. , Collected.

Further, since the EGR gas is introduced into the cylindrical passage formed between the outer tube and the inner tube of the double pipe portion from the tangential direction of the outer tube, the swirling flow is generated in the cylindrical passage. The condensed water formed and contained in the EGR gas adheres to the inner surface of the outer tube by the centrifugal force of the swirling flow.
However, in the LPL-EGR system described in Patent Document 1, the condensed water collected on the inner surface of the cylindrical portion of the casing and the condensed water collected on the inner surface of the outer tube of the double pipe portion are temporarily stored in a tank. After collecting, it is discharged outside the vehicle. For this reason, for example, when strong acidic condensate is discharged out of the vehicle as it is while the vehicle is stopped, problems such as partial discoloration of the road surface occur.

JP 2009-041551 A

  An object of the present invention is to prevent foreign matter separated in the first duct of the intake pipe from being discharged outside the vehicle and to bypass the compressor of the supercharger and lead it to the internal combustion engine, thereby causing corrosion, damage and wear of the compressor. An object of the present invention is to provide an exhaust gas recirculation device for an internal combustion engine that can suppress the above.

According to the first aspect of the present invention, the internal combustion engine is mounted with the supercharger, the intake pipe, and the exhaust gas recirculation pipe.
The supercharger is provided with a compressor that pressurizes a fluid obtained by mixing exhaust gas discharged from the internal combustion engine and air to increase the pressure and sends the high-pressure fluid to the internal combustion engine.
The intake pipe has a first intake passage (intake passage upstream of the compressor) provided upstream of the compressor in the fluid flow direction and a second intake air provided downstream of the compressor in the fluid flow direction. A passage (an intake passage on the downstream side of the compressor) is provided.
The exhaust gas recirculation pipe is provided with a flow path (exhaust gas recirculation path) that recirculates the exhaust gas discharged from the internal combustion engine into the first intake passage of the intake pipe.

The intake pipe includes a first duct having a first intake passage formed therein, a second duct having a second intake passage formed therein, and a fluid flowing through the first intake passage of the first duct. Foreign matter separating means for separating the foreign matter contained therein from the fluid and foreign matter discharging means for guiding the foreign matter separated from the fluid in the first intake passage of the first duct to the internal combustion engine by bypassing the compressor are provided. It has been.
As a result, foreign substances such as strongly acidic condensed water separated from the fluid in the first duct of the intake pipe can be led to the internal combustion engine by bypassing the compressor of the supercharger. Wear can be suppressed.
In addition, since the foreign matter such as strongly acidic condensed water separated from the fluid in the first duct of the intake pipe can be led to the internal combustion engine without being discharged outside the vehicle, the road surface is partially discolored. Can be suppressed.

According to the second aspect of the present invention, the ejector that mixes the foreign matter separated from the fluid in the first duct of the intake pipe into the high-pressure fluid pressurized by the compressor, and the fluid in the first intake passage of the first duct. The foreign matter discharging means is constituted by a bypass passage or the like that guides the foreign matter separated from the air to the ejector by bypassing the compressor.
In addition, as a foreign matter discharging means, an ejector that generates a negative pressure by circulation of a high-pressure fluid pressurized by a compressor, and a bypass channel that guides the foreign matter separated from the fluid in the first duct to the ejector by bypassing the compressor It may be provided.
Further, an ejector may be connected between the outlet of the compressor of the supercharger and the second duct. Moreover, you may arrange | position an ejector in the middle of the 2nd duct connected to the outlet of a compressor.

As a result, foreign matter such as strongly acidic condensed water separated from the fluid in the first duct of the intake pipe can be led to the internal combustion engine together with the high-pressure fluid pressurized by the compressor without being discharged outside the vehicle. The occurrence of problems such as partial discoloration of the road surface can be suppressed.
In addition, the action of the ejector creates a flow in which foreign matter actively flows downstream from the compressor of the supercharger, and the foreign matter separated from the fluid in the first duct of the intake pipe is sucked and quickly discharged from the first duct. Can be discharged. Thereby, the foreign material separated from the fluid in the first duct can be quickly discharged from the first duct without requiring a new power source. Therefore, the foreign matter separated from the fluid by the foreign matter separating means can be prevented from being mixed again with the fluid in the first duct, so that the foreign matter separation efficiency can be improved.

According to the invention described in claim 3, the foreign matter discharging means has the negative pressure generating portion that generates the negative pressure acting on the bypass flow path by the differential pressure generated before and after the ejector.
Here, when the negative pressure generating portion is provided inside the ejector, the ejector having the negative pressure generating portion removes the foreign matter separated from the fluid in the first duct by the negative pressure acting on the bypass flow passage. And sucked into the second duct.
In addition, when the ejector is provided with a nozzle through which the high-pressure fluid pressurized by the compressor flows, and a negative pressure generator that generates a negative pressure acting on the bypass flow path by the ejection of the high-pressure fluid from the nozzle The negative pressure generating unit sucks the foreign matter separated from the fluid in the first duct by the negative pressure suction force generated when the high pressure fluid is ejected from the nozzle into the second duct via the bypass channel. Parts. The ejector mixes the sucked foreign matter into the high-pressure fluid pressurized by the compressor, and guides the high-pressure fluid mixed with the foreign matter to the internal combustion engine.

In addition, the foreign substance collection part which collects the foreign substance isolate | separated from the fluid in a 1st duct is provided as a foreign substance separation means, and the foreign substance collection part (foreign substance collection part of a 1st duct) of a foreign substance separation means is provided as a foreign substance discharge means. ) And a negative pressure generating portion of the ejector (negative pressure generating portion of the foreign matter discharging means) may be used.
Further, as the foreign matter separating means, provided is a swirl flow generating means for generating a swirl flow that spirals (spiral) along the wall surface of the first duct in the flow of fluid flowing through the first duct, As the foreign matter discharging means, a bypass flow path connecting the first duct downstream of the swirl flow generating means of the foreign matter separating means and the negative pressure generating portion of the ejector (negative pressure generating portion of the foreign matter discharging means) may be used. good. In this case, the foreign matter collecting part of the foreign matter separating means may or may not be provided.

According to the invention described in claim 4, the supercharger has an impeller that rotates about a rotation shaft, a scroll chamber that rotatably accommodates the impeller, and an outlet that allows high-pressure fluid to flow out from the scroll chamber. It has a compressor.
The ejector is disposed (connected) between the outlet of the compressor and the second duct of the intake pipe. In this case, when the high-pressure fluid pressurized by the compressor flows through the inside of the ejector, the ejector generates a negative pressure that acts on the bypass flow path. As a result, the foreign matter sucked into the ejector is mixed into the high-pressure fluid pressurized by the compressor. The high-pressure fluid mixed with foreign matter is guided to the internal combustion engine through the second intake passage of the second duct.

According to the invention described in claim 5, the ejector is disposed in the second intake passage of the second duct. In this case, when the high-pressure fluid pressurized by the compressor flows through the inside of the ejector, the ejector generates a negative pressure that acts on the bypass flow path. As a result, foreign matter sucked into the ejector (second intake passage of the second duct) is mixed into the high-pressure fluid pressurized by the compressor. The high-pressure fluid mixed with foreign matter is guided to the internal combustion engine through the second intake passage of the second duct.
According to the sixth aspect of the present invention, the second intake passage of the second duct has a cylindrical fluid flow path through which the high-pressure fluid pressurized by the compressor flows around the ejector. In this case, a part of the high-pressure fluid pressurized by the compressor passes through the cylindrical fluid flow path toward the internal combustion engine. The remaining portion of the high-pressure fluid pressurized by the compressor passes through the inside of the ejector and travels toward the internal combustion engine.

According to the invention described in claim 7, the supercharger has an impeller that rotates about a rotation shaft, a scroll chamber that rotatably accommodates the impeller, and an outlet that allows high-pressure fluid to flow out from the scroll chamber. It has a compressor.
The second intake passage of the second duct is located upstream of the ejector so that the cross-sectional area of the cylindrical fluid passage formed around the ejector is equal to or greater than the opening diameter of the compressor outlet. The passage sectional area of the second intake passage of the second duct is smoothly enlarged on the side. Thereby, even when the ejector is disposed in the second intake passage of the second duct, the pressure loss of the high-pressure fluid that is pressurized by the compressor and flows through the second intake passage can be reduced.

According to the eighth aspect of the present invention, the second duct of the intake pipe is provided with the intercooler that cools the high-pressure fluid pressurized by the compressor.
The ejector is connected in parallel to the intercooler. The intake pipe is provided with a bypass flow path that guides foreign matter separated from the fluid in the first duct to the ejector by bypassing the intercooler.
According to the ninth aspect of the present invention, the foreign matter discharging means (for example, an ejector) is provided with a negative pressure generating portion that generates a negative pressure that acts on the bypass flow path by a differential pressure generated before and after the intercooler. ing.
As a result, by using the differential pressure generated before and after the intercooler in the ejector, a negative pressure that effectively acts on the bypass flow path at the negative pressure generating section without the need for a new differential pressure source (the first pressure) Negative pressure that sucks foreign matter separated from the fluid in one duct into the second duct).

According to the tenth aspect of the present invention, the foreign matter separating means includes a spiral flow that spirals (spiral) along the wall surface of the first duct along the flow of the fluid flowing through the first duct. There is provided a swirl flow generating means for generating. In addition, as a foreign material separation means, you may provide the foreign material collection part which is guided to the outer peripheral part of the swirl | vortex flow generated by the swirl flow generation means, and collects the foreign material isolate | separated from the fluid in the 1st duct.
Here, the foreign matter contained in the exhaust gas has a higher specific gravity than a fluid obtained by mixing exhaust gas and air. For this reason, the inertial force (centrifugal force of the swirl flow) acting on the foreign matter by the swirl flow generated by the swirl flow generating means is larger than the centrifugal force acting on the fluid. As a result, foreign matter having a large specific gravity due to the centrifugal force of the swirling flow tends to gather at the outer peripheral portion of the swirling flow, that is, the outer peripheral portion of the first intake passage, and the fluid having a low specific gravity is collected at the central portion of the swirling flow, that is, the first intake passage Try to gather in the center of the.

Accordingly, centrifugal force acts on the foreign matter by the swirling flow generated by the swirling flow generating means, and the foreign matter is guided to the outer peripheral portion of the swirling flow, that is, the outer peripheral portion of the first intake passage. And the foreign material which was guide | induced to the outer peripheral part of the swirl | vortex flow generated by the swirl | vortex flow generation means and isolate | separated from the fluid is collected by the foreign material collection part, for example. As described above, since the foreign matter can be efficiently separated (centrifugated) from the fluid by utilizing the centrifugal force of the swirling flow generated by the swirling flow generating means, the fluid of the supercharger can Can be allowed to flow into.
As a result, it is possible to avoid problems such as carbon particles, icing or debris due to breakage of the filter flowing into the compressor, so that the impeller of the compressor is damaged or worn due to collision of foreign matter contained in the exhaust gas. Can be suppressed. Further, for example, foreign matter such as strongly acidic condensate can be prevented from flowing into the compressor, so that it does not adhere to or accumulate on a compressor made of a metal material such as an aluminum alloy. Corrosion of equipment (such as an intercooler) provided in the passage and the intake pipe can be suppressed.
In addition, the foreign material collection part does not need to be provided.

According to the eleventh aspect of the present invention, the foreign matter separating means is provided with the foreign matter collecting portion for collecting the foreign matter separated from the fluid in the first duct. In place of the swirl flow generating means, other foreign matter separating means such as a filter may be provided.
According to the twelfth aspect of the present invention, the foreign matter collecting part has a tank for collecting foreign matter separated from the fluid in the first duct.
Here, as a foreign matter discharge means, an ejector that generates a negative pressure by circulation of a high-pressure fluid pressurized by a compressor, and a bypass flow path that guides the foreign matter separated from the fluid in the first duct to the ejector while bypassing the compressor As a bypass flow path, a bypass flow that connects the internal space (foreign matter storage space) of the tank and the ejector (negative pressure generating portion of the foreign matter discharge means) through a slit opened at the bottom of the tank A road may be used.
In addition, you may form the slit connected to the bypass flow path of a foreign material discharge | emission means so that it may open in the lowest part of the gravity direction in the internal space (foreign material storage space) formed in a 1st duct.

According to the thirteenth aspect of the present invention, the exhaust gas control valve for adjusting the flow rate of the exhaust gas flowing through the exhaust gas recirculation pipe is provided. In this case, the exhaust gas whose flow rate is adjusted by an exhaust gas control valve (for example, an EGR gas flow control valve) is supplied to the outside of the intake system of the internal combustion engine, compared with the case where foreign matter separated from the fluid, particularly the exhaust gas, is discharged to the exhaust system. There is no fear of leaking into the internal combustion engine, and it can be returned to the internal combustion engine. Thus, from the target EGR rate (corresponding to the flow rate of EGR gas to the flow rate of all gases supplied to the combustion chamber of the internal combustion engine = EGR rate) set corresponding to the operating state of the internal combustion engine, the actual combustion chamber EGR rate Since the problem of shifting can be prevented, it is possible to suppress the deterioration of emission and the problem that the combustion state becomes unstable.
According to the fourteenth aspect of the present invention, the second duct of the intake pipe is provided with an intercooler that cools the high-pressure fluid pressurized by the compressor.
According to the invention described in claim 15, the supercharger includes an impeller that rotates about a rotation shaft, a scroll chamber that rotatably accommodates the impeller, an inlet that allows fluid to flow into the scroll chamber, and the scroll chamber. A compressor having an outlet through which more fluid flows;

1 is a configuration diagram illustrating an engine control system (Example 1). FIG. It is the schematic which showed the principal part of the LPL-EGR system (Example 1). (A), (b) is the schematic and sectional drawing which showed the swirl | vortex flow generator (Example 1). (A), (b) is the schematic and sectional drawing which showed the swirl | vortex flow generator (Example 2). (A) is AA sectional drawing of (b), (b) is the schematic which showed the swirl | vortex flow generator (Example 3). (Example 4) which is the block diagram which showed the engine control system. (Example 4) which is the schematic which showed the principal part of the LPL-EGR system. (Example 4) which is the schematic which showed the principal part of the LPL-EGR system. (Example 5) which is the schematic which showed the principal part of the LPL-EGR system. (A) is the schematic which showed the principal part of the foreign material separation apparatus, (b) is BB sectional drawing of (a) (Example 6). (A) is the schematic which showed the principal part of the foreign material separation apparatus, (b) is CC sectional drawing of (a) (Example 7).

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The purpose of the present invention is to suppress the corrosion, breakage and wear of the compressor without discharging foreign matter such as strongly acidic condensate separated from the fluid in the first duct of the intake pipe, and supercharging it. This was achieved by bypassing the compressor of the machine and guiding it to the ejector.
In addition, the purpose of improving the foreign matter separation efficiency is to create a flow in which foreign matter is actively flowed downstream from the compressor of the supercharger by the action of the ejector, and the foreign matter separated from the fluid in the first duct of the intake pipe This was realized by sucking and quickly discharging from the first duct.
Further, there is no fear that the exhaust gas whose flow rate is adjusted by an exhaust gas control valve (for example, an EGR gas flow rate control valve) leaks out of the intake system of the internal combustion engine, and the purpose of returning the exhaust gas to the internal combustion engine is the first of the intake pipes. Foreign matter such as strongly acidic condensate separated from the fluid in the duct (the intake passage upstream of the compressor) is led to the internal combustion engine together with the high-pressure fluid pressurized by the compressor, bypassing the compressor of the supercharger. That was realized.

[Configuration of Example 1]
1 to 3 show Embodiment 1 of the present invention, FIG. 1 is a view showing an engine control system, FIG. 2 is a view showing a main part of an LPL-EGR system, and FIG. It is the figure which showed the flow generator.

An internal combustion engine control apparatus (hereinafter referred to as an engine control system) according to the present embodiment is an EGR that is a part of exhaust gas flowing out from an internal combustion engine (hereinafter referred to as an engine body E) such as a diesel engine having a plurality of cylinders. Exhaust gas recirculation device (EGR control device for internal combustion engine: hereinafter referred to as EGR system) that recirculates (recirculates) gas to the intake pipe, and this EGR system as a fuel injection device, a blow-by gas reduction device (PCV system), etc. And an engine control unit (ECU) that performs control in association with the.
These EGR system, fuel injection device, and PCV system are mounted in an engine room of a vehicle such as an automobile.

The engine body E employs a direct injection diesel engine in which fuel is directly injected into the combustion chamber. The engine body E has a plurality of cylinders (first to fourth cylinders), a cylinder block in which the first to fourth cylinders are arranged in series in the cylinder arrangement direction, and a downstream end portion (intake manifold) of the intake pipe And a cylinder head to which an upstream end (exhaust manifold) of the exhaust pipe is connected.
Inside the cylinder block of the engine body E, four combustion chambers are formed in the cylinder arrangement direction. Further, in a cylinder bore formed inside each cylinder of the cylinder block, a piston connected to a crankshaft via a connecting rod is supported so as to be slidable in the central axis direction of the cylinder bore.

On one side of the cylinder head of the engine body E, a plurality of intake ports (intake ports) connected independently to the combustion chambers for each cylinder are provided. The intake port for each cylinder is opened and closed by a poppet-type intake valve (intake valve). An intake passage (intake passage of the internal combustion engine) formed in the intake pipe is connected to an intake port for each cylinder of the engine body E.
On the other side of the cylinder head of the engine body E, there are provided a plurality of exhaust ports (exhaust ports) that are independently connected to the combustion chamber for each cylinder. The exhaust port for each cylinder is opened and closed by a poppet type exhaust valve (exhaust valve). An exhaust passage (exhaust passage of the internal combustion engine) formed in the exhaust pipe is connected to the exhaust port of each cylinder of the engine body E.

The fuel injection device is constituted by a common rail fuel injection system (accumulated pressure fuel injection device) known as a fuel injection system for a diesel engine. This common rail fuel injection system includes a fuel injection pump (supply pump) that incorporates a feed pump that pumps low pressure fuel from a fuel tank on the low pressure side of the fuel system, and a common rail into which high pressure fuel is introduced from the discharge port of the supply pump. And a plurality of fuel injection valves (injectors) to which high-pressure fuel is distributed and supplied from each fuel outlet of the common rail, and the high-pressure fuel accumulated in the common rail is passed through each injector to each cylinder of the engine body E. Each combustion chamber is configured to be supplied by injection.
Here, an electromagnetic fuel metering valve for controlling the fuel discharge amount of the supply pump, and each solenoid valve for controlling the valve opening timing (injection timing) and the valve opening period (fuel injection amount) of the plurality of injectors (for the injector) The amount of current supplied to the solenoid valve) is configured to be electronically controlled by the ECU.

  The PCV system re-enters the intake system of the engine body E without releasing the gas (blow-by gas: hereinafter referred to as PCV gas) that blows into the crankcase from the gap between the piston and the cylinder of the engine body E into the atmosphere. This is a system for returning and reburning. That is, the PCV system extracts the PCV gas generated inside the crankcase of the engine body E, returns it to the intake system (surge tank or intake manifold) of the engine body E, and re-combusts it. Fresh air (clean air from which foreign matter contained in the outside air has been removed) is introduced into the crankcase to ventilate the crankcase.

The PCV system includes a fresh air introduction hose (PCV hose) 3 that connects the inside of the engine body E, particularly the inside of the crankcase (crank chamber) and the intake passage in the air cleaner hose 2, and the inside of the engine body E, particularly the cylinder. A blow-by gas recirculation hose connecting the inside of the head cover and the inside of the surge tank or the intake manifold is provided.
Inside the PCV hose 3, a fresh air introduction passage is formed for guiding clean air (clean air) filtered by the air cleaner 1 to the inside of the engine body E, particularly the inside of the crankcase (crank chamber). . Further, a blow-by gas recirculation passage for returning PCV gas generated in the crankcase (in the crank chamber) to the intake system (surge tank or intake manifold) of the engine body E is formed inside the blow-by gas recirculation hose. Yes.
A PCV valve that is opened and closed according to the operating state of the engine body E is installed in the middle of the blow-by gas recirculation passage.

The engine body E is connected to an intake pipe that forms an intake passage that communicates with the intake ports of all the cylinders, and an exhaust pipe that forms an exhaust passage that communicates with the exhaust ports of all the cylinders.
The intake pipe is used to supply intake air (fresh air) or a fluid in which fresh air and EGR gas are mixed (hereinafter also referred to as a mixed fluid or a fluid such as EGR gas) into the combustion chamber of each cylinder of the engine body E. It is a casing (intake introduction duct) that forms an intake passage. The intake pipe includes an outside air introduction duct, an air cleaner case of the air cleaner 1, an air cleaner hose 2, a first intake duct (intake pipe, first duct) 4, a second intake duct (intake pipe, second duct) 5, and a third intake. It has a duct (intake pipe, second duct) 6 and the like.

Here, the intake manifold includes a surge tank that reduces pressure pulsation of intake air, and a plurality (for each cylinder) of intake branch pipes that are respectively connected to a plurality (for each cylinder) of air outlets of the surge tank. This is a surge tank integrated intake manifold.
The intake pipe includes an air cleaner 1 that traps and removes impurities (dust such as dust, dust, and sand) contained in the outside air flowing from the outside air introduction duct, and clean air (fresh air) filtered by the air cleaner 1. A foreign matter separation device that removes foreign matter from a fluid mixed with EGR gas, and a fluid (EGR gas or mixed fluid) from which foreign matter has been removed by this foreign matter separation device is supercharged to increase the pressure in the combustion chamber of each cylinder of the engine body E A turbocharger compressor that feeds fluid, an ejector 8 through which high-pressure fluid pressurized (compressed or accelerated) flows, and a high pressure that has been pressurized by the turbocharger compressor and increased in intake pressure. An intercooler 9 for cooling the fluid, a throttle valve 10 for adjusting the flow rate of the intake air introduced into the intake port of each cylinder of the engine body E, and the like It is location.

Here, the foreign matter separating device includes a swirling flow generator (swirl flow generating means) 7 disposed in the first intake duct 4 and an outer periphery of the swirling flow by the centrifugal force of the swirling flow generated by the swirling flow generating device 7. And a foreign matter collecting part for collecting foreign matter separated from a fluid obtained by mixing EGR gas and intake air.
In addition, in the intake pipe of the present embodiment, the foreign matter separated from the fluid in the first intake duct 4 by the action of the foreign matter separating device bypasses the compressor of the turbocharger and is taken into each cylinder of the engine body E. A foreign matter discharge device (foreign matter discharge means) leading to the port and the combustion chamber is installed. This foreign matter discharging apparatus separates the foreign matter separated from the fluid in the first intake duct 4 from the fluid in the ejector 8 that mixes the high pressure fluid pressurized by the compressor of the turbocharger and the first intake duct 4. A bypass flow path 12 or the like for guiding foreign matter to the ejector 8 by bypassing the compressor is provided. In the middle of the bypass flow path 12, a check valve 13 is installed to prevent a back flow of fluid containing foreign matter sucked by the ejector 8.
The details of the intake pipe, particularly the first to third intake ducts 4 to 6, the foreign matter separation device, and the foreign matter discharge device (ejector 8, bypass passage 12 and the like) will be described later.

The exhaust pipe is a casing (exhaust exhaust duct) that forms an exhaust passage for exhausting the exhaust gas flowing out from the combustion chamber of each cylinder of the engine body E to the outside. The exhaust pipe has an exhaust manifold, an exhaust duct, an exhaust pipe, and the like.
Here, the exhaust manifold includes a plurality of (for each cylinder) exhaust branch pipes connected to a combustion chamber and an exhaust port for each cylinder of the engine main body E, and a collective portion that is a confluence of the exhaust branch pipes for each cylinder. have.
The exhaust pipe includes a turbocharger turbine, a diesel particulate filter (DPF) 21 that collects particulates (PM) contained in exhaust gas that has passed through the turbine, and exhaust gas that has passed through the DPF 21. A NOx occlusion reduction type catalyst (NOx catalyst) 22 for purifying nitrogen oxide (NOx) contained in the catalyst is installed.

The DPF 21 is a ceramic filter having a known structure. For example, a heat-resistant ceramic such as cordierite is formed into a honeycomb structure so that a large number of cells serving as exhaust gas passages are staggered on the inlet side or the outlet side. It will be sealed. The exhaust gas discharged from the engine main body E flows downstream while passing through the porous partition wall of the DPF 21, and particulates (PM) are collected and gradually accumulated during that time.
An oxidation catalyst (DOC) may be installed in the exhaust pipe upstream of the DPF 21. The DPF 21 may be a metal filter, and may or may not carry an oxidation catalyst. Alternatively, a system configuration in which a DPF carrying an oxidation catalyst is used and no DOC is installed upstream of the DPF can be used.

The DOC has a well-known structure and is formed by supporting an oxidation catalyst on the surface of a ceramic carrier made of a cordierite honeycomb structure or the like. The DOC burns hydrocarbons (HC) supplied to the exhaust passage by a catalytic reaction to raise the exhaust temperature and raise the temperature of the DPF 21. A DOC may be installed in the exhaust pipe downstream of the NOx catalyst 22. In this case, exhaust gas is purified by oxidizing HC and CO that have passed through the NOx catalyst 22 in the DOC.
The NOx catalyst 22 is made of, for example, an alkaline earth material (occlusion material) and platinum. When the atmosphere of the exhaust gas is an air-fuel ratio clean (an air-fuel ratio with a fuel ratio higher than the theoretical air-fuel ratio), NOx in the exhaust gas is removed. When the air-fuel ratio is occluded and the air-fuel ratio becomes rich (the air-fuel ratio is lower than the stoichiometric air-fuel ratio), the stored NOx is reduced and removed by reducing components such as HC and CO in the exhaust gas.

The turbocharger includes a turbine disposed in the middle of an exhaust passage formed in the exhaust pipe, and a compressor disposed in the middle of the intake passage formed in the intake pipe, and includes EGR gas, intake air, This is a turbocharger that pressurizes (compresses or accelerates) the fluid that is mixed into the combustion chamber for each cylinder of the engine body E.
The turbine includes a turbine impeller (turbine wheel) 23 that is rotationally driven by exhaust gas discharged from the engine body E, and a turbine housing 24 that rotatably accommodates the turbine impeller 23.
The compressor is disposed coaxially with the turbine impeller 23 and includes a compressor impeller 25 that is rotationally driven by the turbine impeller 23, and a compressor housing 26 that rotatably accommodates the compressor impeller 25.

Here, the turbine impeller 23 and the compressor impeller 25 are coupled so as to rotate together by a rotor shaft (rotating shaft) 27 that extends straight in the rotating shaft direction. A turbine impeller 23 having a plurality of turbine blades is coupled to one end of the rotor shaft 27 in the rotation axis direction. A compressor impeller 25 having a plurality of compressor blades is coupled to the other end of the rotor shaft 27 in the rotation axis direction.
The turbine impeller 23 rotates about the rotor shaft 27.
The turbine housing 24 has a scroll portion in which a scroll chamber 28 for accommodating the turbine impeller 23 is formed. The scroll chamber 28 includes a spiral fluid flow path (scroll flow path) that surrounds the periphery of the turbine impeller 23.

An inlet for allowing exhaust gas to flow into the scroll chamber 28 of the turbine housing 24 from the exhaust duct on the exhaust manifold side is integrally formed on the upstream side of the scroll portion of the turbine housing 24. Inside this inlet, a fluid introduction flow path connected to an exhaust passage formed in the exhaust duct on the exhaust manifold side is formed.
An outlet for allowing exhaust gas to flow out from the scroll chamber 28 of the turbine housing 24 to the exhaust duct on the DPF side is integrally formed on the downstream side of the scroll portion of the turbine housing 24. Inside this outlet, there is formed a fluid discharge passage connected to an exhaust passage formed in the exhaust duct on the DPF side.

The compressor impeller 25 rotates around the rotor shaft 27.
The compressor housing 26 has a scroll portion in which a scroll chamber 29 for accommodating the compressor impeller 25 is formed. The scroll chamber 29 includes a spiral fluid channel (scroll channel) that surrounds the periphery of the compressor impeller 25.
An inlet 31 is formed integrally on the upstream side of the scroll portion of the compressor housing 26 to allow fluid to flow from the first intake duct (intake duct closer to the air cleaner than the compressor) 4 to the scroll chamber 29 of the compressor housing 26. ing. A fluid suction flow path 32 connected to a first intake passage formed in the first intake duct 4 is formed inside the inlet 31. Further, a cylindrical duct connecting portion (joining portion) connected to the first intake duct 4 is formed at the upstream end portion of the inlet 31.

The compressor housing 26 is made of a metal material such as an aluminum alloy.
On the downstream side of the scroll portion of the compressor housing 26, an outlet 33 for allowing the high-pressure fluid to flow out from the scroll chamber 29 of the compressor housing 26 to the second intake duct (intake duct on the intercooler side of the compressor) 5 is integrally formed. Is formed. Inside the outlet 33, a fluid discharge channel 34 connected to an axial channel formed in the ejector 8 is formed. Further, a cylindrical ejector connecting portion (joining portion) connected to the ejector 8 is formed at the downstream end portion of the outlet 33.

  Here, the EGR system (exhaust gas recirculation device) of this embodiment includes an exhaust pipe having an exhaust passage formed therein, an intake pipe having an intake passage formed therein, and a scroll of the turbine housing 24 of the turbocharger. High-pressure EGR gas from the exhaust passage upstream of the chamber 28 (exhaust duct on the exhaust manifold side of the turbine) to the intake passage (intake duct on the intake manifold side of the compressor) downstream of the scroll chamber 29 of the compressor housing 26 A high-pressure exhaust gas recirculation device (HPL-EGR system) that recirculates gas, and an exhaust passage downstream of the scroll chamber 28 of the turbine housing 24 of the turbocharger, in particular, an exhaust passage downstream of the DPF 21 (downstream of the DPF 21) From the exhaust duct) to the compressor housing 26 And a low-pressure exhaust gas recirculation system in which the first intake passage to the upstream (first intake duct 4) recirculates the low pressure EGR gas (LPL-EGR system) than roll chamber 29.

The HPL-EGR system includes a high-pressure exhaust gas recirculation pipe (HPL-EGR pipe: hereinafter referred to as an EGR gas pipe) 35 that recirculates high-pressure EGR gas (hereinafter also referred to as EGR gas) from the exhaust pipe to the intake pipe. Inside the EGR gas pipe 35, an intake passage (intake manifold) downstream from the scroll chamber 29 of the compressor housing 26 from an exhaust passage (exhaust manifold) upstream of the scroll chamber 28 of the turbine housing 24 of the turbocharger. ) Is formed with an EGR gas recirculation path (exhaust gas recirculation path) for recirculating the high-pressure EGR gas.
The EGR gas pipe 35 includes a high-pressure EGR cooler 37 that cools the high-pressure EGR gas that flows through the EGR gas recirculation path, and a high-pressure EGR flow control valve that controls the flow rate of the high-pressure EGR gas that flows through the EGR gas recirculation path (exhaust gas control valve, EGR gas flow rate control valve) 38 and the like are installed. The high pressure EGR cooler 37 may not be provided.

The LPL-EGR system has a low-pressure exhaust gas recirculation pipe (LPL-EGR pipe: hereinafter referred to as EGR gas pipe) 45 that recirculates low-pressure EGR gas (hereinafter also referred to as EGR gas) from the exhaust pipe to the intake pipe. Inside the EGR gas pipe 45, an EGR gas recirculation path (exhaust gas recirculation) for recirculating low pressure EGR gas from the exhaust passage downstream of the DPF 21 to the first intake passage 41 upstream of the scroll chamber 29 of the compressor housing 26. Road) 46 is formed.
The EGR gas pipe 45 includes a low-pressure EGR cooler 47 that cools the low-pressure EGR gas that flows through the EGR gas recirculation path 46, and a low-pressure EGR flow control valve that adjusts the flow rate of the low-pressure EGR gas that flows through the EGR gas recirculation path 46 (exhaust gas control Valve, EGR gas flow rate control valve) 48 and the like are installed. Note that the low-pressure EGR cooler 47 may not be provided.

Next, details of the intake pipe used in the LPL-EGR system of the present embodiment will be described with reference to FIGS. The intake pipe includes a first intake duct 4 in which a first intake passage 41 is formed, a second intake duct 5 in which a second intake passage 42 is formed, and a third intake passage 43 ( A third intake duct 6 is provided in which is formed (see FIGS. 7 and 8).
Here, the first intake passage 41 constitutes an intake passage on the upstream side of the scroll chamber 29 of the compressor housing 26. The second and third intake passages 42 and 43 constitute an intake passage on the downstream side of the scroll chamber 29 of the compressor housing 26.

The first intake duct 4 is installed so as to surround the first intake passage 41 in the circumferential direction, and introduces a fluid obtained by mixing EGR gas and intake air into the scroll chamber 29 of the compressor housing 26. It constitutes a duct.
An upstream end portion of the first intake duct 4 is provided with a junction 49 between clean air (clean air, fresh air) filtered by the air cleaner 1 and EGR gas introduced from the EGR gas pipe 45. In addition, a cylindrical outer tube 51 in which the swirling flow generator 7 is disposed is provided in the entire axial direction of the first intake duct 4. A double pipe portion is provided at the downstream end portion of the first intake duct 4. The double pipe portion is configured by a cylindrical tank 52 which is a downstream end portion of the outer tube 51, and a cylindrical inner tube 53 having a shorter axial length than the outer tube 51. An annular blocking wall that closes the cylindrical space (foreign substance storage space) 54 is provided between the downstream end portion (tank 52) of the outer tube 51 and the downstream end portion of the inner tube 53. .

The outer pipe 51 has a cylindrical inner surface (wall surface, inner peripheral surface) that forms a first intake passage (large diameter passage) 41 therein. The outer pipe 51 is a large-diameter duct (cylindrical duct) having a larger intake passage diameter (passage cross-sectional area) than the inner pipe 53. Further, the downstream side portion (tank 52) of the outer pipe 51 is installed so as to surround the periphery of the foreign substance storage space 54 in the circumferential direction. The outer pipe 51 is set to be larger than the opening diameter (inlet diameter) of the inlet 31 of the compressor housing 26 and the intake passage diameter (duct diameter) of the inner pipe 53.
The first intake duct 4, particularly the outer pipe 51, is formed with an exhaust gas introduction part (EGR gas introduction port) through which EGR gas is introduced from the EGR gas recirculation path 46 of the EGR gas pipe 45 to the first intake path 41. ing.

The inner pipe 53 has a cylindrical inner surface (wall surface, inner peripheral surface) that forms a first intake passage (small-diameter passage) 41 therein. The inner pipe 53 is a small-diameter duct (cylindrical duct) having a smaller intake passage diameter (passage cross-sectional area) than the outer pipe 51. Further, the inner pipe 53 has the same intake passage diameter as the opening diameter of the inlet 31 of the compressor housing 26.
A cylindrical inlet connecting portion (joining portion) that is hermetically connected to the duct connecting portion of the inlet 31 of the compressor housing 26 is formed at the downstream end portion of the inner pipe 53.

Further, as shown in FIGS. 1 to 3, the intake pipe of the present embodiment is in a fluid flowing through the first intake passage 41 of the first intake duct 4 (fluid in which EGR gas and intake air are mixed). The foreign matter separating device that separates and collects the foreign matter contained in the fluid, and the foreign matter separated from the fluid in the foreign matter separating device bypasses the scroll chamber 29 of the compressor housing 26 of the turbocharger. The engine body E is provided with a foreign matter discharge device that leads to an intake port and a combustion chamber for each cylinder.
The foreign matter separating device includes the first intake duct 4, particularly the swirling flow generating device 7 disposed in the outer pipe 51, the double pipe portion provided at the downstream end of the first intake duct 4, and the double pipe A foreign matter collecting portion for collecting the foreign matter separated from the fluid by the inner pipe 53 of the portion.

  As shown in FIG. 3, the swirling flow generating device 7 has a disk-like plate 55 attached to the wall surface of the outer pipe 51 of the first intake duct 4 and the first intake passage 41 of the first intake duct 4. A plurality of fixed swirl blades (propellers) 56 that generate a spiral swirl flow that spirally swirls along the wall surface of the outer tube 51 in the flowing fluid, and a support that supports each of these fixed swirl blades 56 A shaft 57 is provided. The plurality of fixed swirl blades 56 are provided by cutting and raising a plurality of polygonal cut and raised pieces formed on the plate 55 on the upstream side and the downstream side in the thickness direction, and the support shaft 57 is an intake passage (first intake passage). 41) is fixed to the wall surface of the outer tube 51 so as to be positioned on the central axis.

An annular step opening 58 that connects the first intake passage 41 and the foreign substance storage space 54 is formed between the double pipe portions, particularly between the outer pipe 51 and the inner pipe 53. The step opening 58 is disposed on the downstream side of the plurality of fixed swirl blades 56 and on the outer peripheral portion of the first intake passage 41. Further, the step opening 58 opens in an annular shape. Then, the step opening 58 uses the centrifugal force of the swirling flow generated downstream of the plurality of fixed swirl blades 56 by the passage of fluid through the plurality of fixed swirl blades 56 (the first outer peripheral portion (first step)). The foreign substance introduced to the outer peripheral portion of the one intake passage 41 is separated (centrifugated) from the fluid.
The foreign matter collecting part is installed on the outer peripheral part of the first intake duct 4 so as to surround the inner pipe 53 in the circumferential direction. This foreign matter collecting part has a tank 52 for temporarily collecting foreign matter separated from the fluid at the step opening 58. The foreign substance storage space 54 formed in the tank 52 communicates with the first intake passage 41 through the step opening 58. Note that a bypass flow path 12 is connected to the tank 52 via a slit (foreign matter discharge portion) 11.

The foreign matter discharging apparatus includes an ejector 8 that generates a negative pressure by the flow of a high-pressure fluid pressurized by a compressor of a turbocharger, a slit 11 that is opened at the bottom of a tank 52, and a suction port 14 of the ejector 8, and a compressor housing. And 26 bypass chambers 12 that bypass and connect the scroll chambers 29.
The foreign matter discharge device adheres to and collects on the inner surface (wall surface) of the tank 52, or drops and accumulates on the bottom surface located below the gravitational direction in the foreign matter storage space 54 due to the increase in weight due to aggregation. It is a foreign matter discharging means for guiding the foreign matter to the engine body E using a negative pressure suction force generated in the negative pressure generating portion 17 of the ejector 8.

  The ejector 8 is disposed between the downstream end portion (ejector connection portion) of the outlet 33 of the compressor housing 26 and the upstream end portion (ejector connection portion) of the second intake duct 5. On the outer surface of the ejector 8, foreign matter is mixed into the ejector inlet (inlet port) through which high-pressure fluid pressurized by the compressor flows, the suction port 14 for sucking foreign matter from the bypass flow path 12, and the second intake passage 42. The ejector outlet (discharge port) for discharging the high-pressure fluid thus opened is opened. Note that the inlet port and the discharge port are arranged on the same axis.

The ejector 8 generates a negative pressure that acts on the bypass flow path 12 by the ejection of the high-pressure fluid from the nozzle 15 through which the high-pressure fluid pressurized by the compressor flows and the throttle portion 16 (or nozzle outlet portion) of the nozzle 15. A negative pressure generator 17, a mixing unit 18 that mixes the high-pressure fluid ejected from the throttle unit 16 of the nozzle 15 and the foreign matter sucked by the negative pressure generator 17, and a diffuser that increases the pressure of the high-pressure fluid containing the foreign matter 19 etc.
The throttle unit 16 is provided at the outlet of the nozzle 15. Further, the nozzle 15, the mixing unit 18, and the diffuser 19 are provided on the same axis, and constitute an axial flow path of the ejector 8.

  Here, the ejector 8 mixes the sucked foreign matter into the high-pressure fluid pressurized by the compressor, and guides the high-pressure fluid mixed with the foreign matter to the intake port and the combustion chamber of each cylinder of the engine body E. In addition, since the ejector 8 is configured to introduce foreign matter into the negative pressure generating portion 17 provided on the upstream side of the throttle portion 16 of the nozzle 15, separation of the flow of foreign matter flowing through the bypass channel 12, etc. It has a shape with little pressure loss.

  The negative pressure generator 17 is a negative pressure that acts on the bypass flow path 12 by the differential pressure generated before and after the ejector 8 (upstream side of the inlet port and the inlet port, discharge port and downstream side of the discharge port). Is generated. The negative pressure generator 17 is provided in the first intake duct 4, that is, a foreign substance that is centrifuged in the first intake duct 4 by the negative pressure suction generated when the high-pressure fluid is ejected from the throttle portion 16 of the nozzle 15. A foreign matter suction part that sucks the foreign matter collected in the foreign matter storage space 54 into the second intake passage 42 provided in the second intake duct 5 via the bypass flow path 12 and the suction port 14 is configured.

  The bypass passage 12 is a foreign matter discharge passage that guides foreign matter collected in the foreign matter storage space 54 provided in the first intake duct 4 to the ejector 8 by bypassing (bypassing) the scroll chamber 29 of the compressor housing 26. is there. The bypass flow path 12 is connected to the foreign matter collecting part of the foreign matter separating device through the slit 11 opened at the bottom surface of the tank 52 provided in the first intake duct 4 and the suction port 14 opened at the outer surface of the ejector 8. The negative pressure generator 17 of the ejector 8 is connected.

The downstream end of the bypass flow path 12 is connected to the suction port 14 of the negative pressure generator 17 provided in the ejector 8. The bypass flow path 12 is formed inside a bypass pipe 20 that connects the tank 52 of the first intake duct 4 and the suction port 14 of the ejector 8.
The upstream end of the bypass passage 12 is downstream of the swirl flow generating device 7 such as the foreign matter collecting portion of the foreign matter separating device, that is, the plurality of fixed swirl blades 56, through the slit 11 opened at the bottom of the tank 52. Are connected to the tank 52 of the first intake duct 4.
Here, the slit 11 formed in the tank 52 having a function as a foreign matter collecting part is a position that is the lowest part in the gravitational direction (vehicle vertical direction) of the foreign matter storage space 54 formed in the first intake duct 4. Open in the vicinity.
The check valve 13 is installed in the middle of the bypass flow path 12 and is sucked into the high pressure fluid (high pressure fluid mixed with foreign matter or the negative pressure generating portion 17 of the ejector 8) pressurized by the compressor of the turbocharger. It has a ball valve that prevents backflow of foreign matter), a valve seat on which the ball valve is seated and separated, and a valve hole (bypass passage hole) that passes through the valve seat.

[Operation of Example 1]
Next, the operation of the engine control system of this embodiment will be briefly described with reference to FIGS.

  Exhaust gas discharged from the engine body E is introduced into the scroll passage of the scroll chamber 28 from a fluid introduction passage formed in the inlet. The exhaust gas that has obtained a rotational force when passing through the scroll flow path of the scroll chamber 28 is blown to the turbine blades of the turbine impeller 23 through the fluid inlet formed on the inner surface of the scroll chamber 28. The turbine impeller 23 is rotated about the rotor shaft 27 by the exhaust gas thus blown onto the turbine blade. Thereby, the rotor shaft 27 rotates. Then, the exhaust gas blown to the turbine impeller 23 passes through a fluid discharge port opened on the front side of the turbine impeller 23, and is discharged from the fluid discharge passage formed in the outlet to the exhaust duct on the DPF side.

  When the rotation of the turbine impeller 23 is transmitted to the compressor impeller 25 via the rotor shaft 27, the compressor impeller 25 rotates. When the compressor impeller 25 rotates, the intake air or the mixed fluid is sucked from the fluid suction passage 32 formed in the inlet 31 through the fluid suction port opened on the front side of the compressor impeller 25. The intake air or mixed fluid sucked into the compressor impeller 25 in this way is compressed by the compressor blade of the compressor impeller 25 and is forcibly sent to the scroll flow path of the scroll chamber 29. Then, the high-pressure fluid sent to the scroll passage of the scroll chamber 29 is sent to the fluid discharge passage 34 formed in the outlet 33 through the fluid discharge port formed on the inner surface of the scroll chamber 29. Then, the high-pressure fluid sent to the fluid discharge flow path 34 is an axial flow path (nozzle 15, mixing unit 18 and diffuser 19) of the ejector 8, a second intake passage 42 formed in the second intake duct 5, The air is sent to the intake port and the combustion chamber of each cylinder of the engine body E through the intercooler 9, the third intake passage 43 formed in the third intake duct 6, and the throttle valve 10.

Here, at the upstream end portion of the first intake duct 4, clean air (clean air, fresh air) filtered by the air cleaner 1 and EGR gas introduced from the EGR gas recirculation path 46 of the EGR gas pipe 45. A junction 49 is provided. When the low-pressure EGR flow control valve 48 installed in the EGR gas pipe 45 is open, the EGR gas pipe is connected to the exhaust passage downstream of the outlet of the turbine housing 24, particularly from the exhaust passage downstream of the DPF 21. The EGR gas is introduced into the first intake passage 41 upstream of the scroll chamber 29 of the compressor housing 26 via the 45 EGR gas recirculation passage 46.
Then, the EGR gas and the intake air are mixed in the first intake passage 41 of the first intake duct 4 to become a mixed fluid (fluid such as EGR gas). When this mixed fluid passes through a plurality of fixed swirl vanes 56 disposed in the middle of the first intake passage 41 of the first intake duct 4, the mixed fluid spirals along the wall surface of the outer pipe 51. A spiral swirling flow is generated.

Here, foreign matters (for example, carbon fine particles, condensed water, icing, debris when the DPF 21 is broken, etc.) contained in the EGR gas introduced into the first intake passage 41 of the first intake duct 4 are the intake air and the EGR. Specific gravity is large compared with the fluid (mixed fluid) which mixed gas. For this reason, the inertial force (centrifugal force of the swirl flow) acting on the foreign matter by the swirling flow of the mixed fluid generated by passing through the plurality of fixed swirl blades 56 is larger than the centrifugal force acting on the mixed fluid.
As a result, foreign matter having a large specific gravity (carbon fine particles, condensed water, icing, debris when the DPF 21 is broken, etc.) due to centrifugal force of the swirl flow is removed from the outer periphery of the swirl flow, that is, the intake passage (particularly the first in the outer pipe 51). The mixed fluid (intake air, EGR gas, etc.) having a small specific gravity tries to gather on the outer periphery of the one intake passage 41), and the center portion of the swirling flow, that is, the intake passage (particularly the first intake passage 41 in the outer pipe 51). Try to gather in the center.

  Accordingly, the foreign matter reaches the vicinity of the upstream end portion of the inner tube 53 while spirally turning along the wall surface (inner peripheral surface) of the cylindrical outer tube 51. The foreign matter that has reached the vicinity of the upstream end portion of the inner pipe 53 flows into the foreign matter storage space 54 through the annular step opening 58 as it is. Then, the foreign matter that has been centrifuged from the mixed fluid by the swirling flow of the mixed fluid and has flowed into the foreign matter storage space 54 is circumferential along the wall surface (outer peripheral surface) of the cylindrical inner tube 53. Turn to. The foreign matter swirling in the foreign matter storage space 54 is collected by adhering to the inner surface (wall surface) of the tank 52 due to the centrifugal force of the swirl flow, or the gravity in the foreign matter storage space 54 due to the increase in its own weight due to aggregation. It falls and accumulates on the bottom surface located in the lower direction.

Here, when the high pressure fluid pressurized by the compressor of the turbocharger flows through the nozzle 15 of the ejector 8 and the high pressure fluid is ejected from the throttle portion 16 of the nozzle 15, the negative pressure generating portion 17 of the ejector 8 is supplied. A negative pressure (negative pressure suction force that sucks foreign matter collected or deposited in the tank 52 through the bypass passage 12) acting on the bypass passage 12 is generated. As a result, the foreign matter collected or accumulated in the tank 52 is sucked from the foreign matter storage space 54, which is the internal space of the tank 52, through the bypass channel 12 and the suction port 14 to the negative pressure generating unit 17. At this time, a part of the mixed fluid is also sucked into the negative pressure generation unit 17 through the bypass channel 12 and the suction port 14 together with the foreign matter.
The foreign matter sucked by the negative pressure generating unit 17 (and the mixed fluid sucked together with the foreign matter) is mixed with the high-pressure fluid pressurized by the compressor of the turbocharger in the mixing unit 18 of the ejector 8. The high-pressure fluid containing foreign matter passes through the second intake passage 42 formed in the second intake duct 5, the intercooler 9, the third intake passage 43 formed in the third intake duct 6, and the throttle valve 10. Then, it is guided to the intake port and the combustion chamber for each cylinder of the engine body E.

[Effect of Example 1]
As described above, in the EGR system of this embodiment, particularly the LPL-EGR system, the exhaust passage on the downstream side of the scroll chamber 28 of the turbine housing 24 of the turbocharger, particularly the exhaust passage on the downstream side of the DPF 21. An EGR gas recirculation passage 46 for recirculating EGR gas is provided in the first intake passage 41 upstream of the scroll chamber 29 of the compressor housing 26.
A fluid (mixed fluid, fluid such as EGR gas) obtained by mixing EGR gas introduced from the EGR gas recirculation path 46 with clean air (clean air, fresh air) filtered by the air cleaner 1 is supplied to each engine body E. A first intake duct 4 in which a first intake passage (an intake passage on the upstream side of the scroll chamber 29 of the compressor housing 26) 41 is formed is formed in an intake port for each cylinder and an intake pipe that is fed into the combustion chamber. The second intake duct 5 in which the second intake passage (the intake passage on the downstream side of the scroll chamber 29 of the compressor housing 26) 42 is formed, and the fluid flowing through the first intake passage 41 of the first intake duct 4 Foreign matter separating device (swirl flow generator 7, double pipe portion and foreign matter collecting portion) for separating foreign matter contained in the fluid from the fluid, and first intake duct 4 Foreign matter discharging device (ejector 8) that guides foreign matter separated from the fluid in the first intake passage 41 to the intake port and the combustion chamber for each cylinder of the engine body E by bypassing the scroll chamber 29 of the compressor housing 26. A bypass flow path 12 and a check valve 13).

As a result, foreign substances contained in the EGR gas due to the swirling flow generated by the swirling flow generating device 7 constituted by a plurality of fixed swirling blades 56 and the like (for example, carbon fine particles, condensed water, freezing, debris accompanying damage to the DPF 21). Centrifugal force acts on the outer peripheral portion of the swirl flow, that is, the outer peripheral portion of the first intake passage 41. The foreign matter is separated from the fluid by the inner pipe 53 and the step opening 58 provided at the downstream end of the first intake duct 4. The foreign matter separated from the fluid by the inner pipe 53 and the step opening 58 is collected by adhering to the inner surface (wall surface) of the tank 52, or in the gravitational direction in the foreign matter storage space 54 due to the increase in weight due to aggregation. It drops and accumulates on the bottom surface.
The foreign matter collected or deposited in the tank 52 provided at the downstream end of the first intake duct 4 is bypassed by the action of the ejector 8 (negative pressure suction force generated by the negative pressure generating portion 17). Then, it is sucked into the negative pressure generator 17 through the engine and further mixed into the high-pressure fluid pressurized by the compressor in the mixing unit 18 and then introduced into the intake port and the combustion chamber of each cylinder of the engine body E.

Here, when the EGR gas containing the acidic substance is recirculated to the first intake passage 41 via the EGR gas recirculation path 46 of the EGR gas pipe 45 of the LPL-EGR system, the air that has passed through the air cleaner 1 When the EGR gas is cooled, it condenses with the water vapor contained in the EGR gas to generate strongly acidic condensed water. If the strongly acidic condensate adheres to and accumulates on the compressor housing 26 made of a metal material such as an aluminum alloy, the compressor housing 26 may be corroded. Moreover, when the collected strongly acidic condensate is discharged out of the vehicle as it is, as in the LPL-EGR system described in Patent Document 1, problems such as partial discoloration of the road surface occur.
In order to deal with such problems, in the EGR system of this embodiment, particularly the LPL-EGR system, strongly acidic condensed water collected in the tank 52 provided at the downstream end of the first intake duct 4 and the like. Without being discharged outside the vehicle, together with the high pressure fluid pressurized by the compressor of the turbocharger, can be led to the intake port and the combustion chamber for each cylinder of the engine body E. Even when the vehicle is stopped, it is possible to suppress the occurrence of problems such as partial discoloration of the road surface.

In addition, the foreign matter discharging apparatus of the present embodiment bypasses the scroll chamber 29 of the compressor housing 26 for the foreign matter separated from the fluid by the foreign matter separation device, that is, the foreign matter collected in the tank 52 of the first intake duct 4. ) To the intake system of the engine body E (the second intake passage 42 of the second intake duct 5).
As a result, the EGR gas whose flow rate has been adjusted by the low pressure EGR flow control valve 48 is changed from that of the engine body E to the case where foreign matter such as strongly acidic condensed water separated from the EGR gas is discharged to the exhaust system of the engine body E. There is no fear of leaking out of the intake system, and it can be recirculated to the intake port and combustion chamber of each cylinder of the engine body E. Thereby, from the target EGR rate (the ratio of the flow rate of EGR gas to the flow rate of all the gases supplied to the combustion chamber of the engine body E = EGR rate) set corresponding to the operating state (operating state) of the engine body E. Since the problem that the actual combustion chamber EGR rate shifts can be prevented, it is possible to suppress the problem that the emission is deteriorated or the combustion state is unstable.

Further, foreign matter such as strongly acidic condensed water collected in a tank 52 provided at the downstream end of the first intake duct 4 is guided to the ejector 8 by bypassing the compressor housing 26 of the turbocharger. Therefore, it is possible to suppress the occurrence of a problem that the compressor housing 26 made of a metal material such as an aluminum alloy corrodes.
Also, the action of the ejector 8 creates a flow in which foreign matter actively flows to the downstream side of the scroll chamber 29 of the compressor housing 26, and the foreign matter collected or deposited in the tank 52 is sucked to promptly collect the first intake duct 4. In particular, it can be discharged from the foreign substance storage space 54 of the tank 52. Accordingly, the foreign matter separated from the fluid in the first intake duct 4 can be quickly discharged from the foreign matter storage space 54 of the tank 52 without requiring a new power source. Therefore, since the foreign matter separated from the fluid by the foreign matter separation device can be prevented from being mixed again in the fluid due to staying in the first intake duct 4 for a long time, the foreign matter separation efficiency can be improved.

Here, in the exhaust passage on the downstream side of the scroll chamber 28 of the turbine housing 24 of the turbocharger, as shown in FIG. 1, the particulate matter contained in the exhaust gas discharged from the engine body E ( A DPF 21 that collects so-called PM) is installed.
However, in the exhaust emission control device provided with the DPF 21, the PM collected by the DPF 21 is increased in temperature by the heater or fuel injection control (post injection) and combusted by a catalytic reaction. . However, when a large amount of PM suddenly burns, the temperature rises too much, and the DPF 21 may be damaged (melting and cracking). In this case, if the debris when the DPF 21 is broken is recirculated through the EGR gas pipe 45 to the first intake passage 41, the debris collides with the compressor impeller 25 and promotes breakage and wear of the compressor impeller 25. There is a problem.

  To deal with such problems, the EGR system of this embodiment, particularly the LPL-EGR system, utilizes the centrifugal force of the swirl flow generated by the swirl flow generator 7 composed of a plurality of fixed swirl blades 56 and the like. Thus, foreign matter can be efficiently separated (centrifugated) from the fluid. For example, a fluid containing almost no foreign matter such as carbon fine particles, condensed water, freezing, and debris due to breakage of the DPF 21 is removed from the compressor housing 26 of the turbocharger. The scroll chamber 29 formed therein, that is, the scroll chamber 29 in which the compressor impeller 25 is rotatably accommodated can be allowed to flow. As a result, the compressor impeller 25 can be prevented from being damaged or worn by collision of foreign matter contained in EGR gas introduced into the intake passage (first intake passage 41) upstream of the scroll chamber 29 of the compressor housing 26. Can do.

FIG. 4 shows a second embodiment of the present invention, and FIG. 4 shows a swirl flow generator.
The intake pipe of the present embodiment has a swirling flow generator 7 provided integrally with a cylindrical first intake duct 4 connected to an inlet 31 of a compressor housing 26 of a turbocharger. Foreign matter separation that separates foreign matter (for example, carbon fine particles, condensed water, icing, debris caused by breakage of DPF 21) from the fluid in which EGR gas and intake air are mixed using the centrifugal force of the swirling flow generated by the device 7 Equipment.

The swirling flow generator 7 generates a spiral swirling flow that spirally swirls along the wall surface (cylindrical inner surface) of the first intake duct 4 in the flow of fluid such as EGR gas flowing through the first intake passage 41. The swirling flow generating means is configured.
Here, the first intake duct 4 constituting the swirling flow generating device 7 constitutes a casing of the foreign matter separating device, and the first intake passage 41, particularly the intake air and EGR, upstream of the scroll chamber 29 of the compressor housing 26. It is installed so as to surround the periphery of the junction 49 with the gas.

Further, the first intake duct 4 is formed with an EGR introduction pipe 61 connected to the downstream end of the EGR gas pipe 45. The EGR introduction pipe 61 includes an EGR gas introduction passage 62 connected to the downstream end of the EGR gas recirculation passage 46 formed in the EGR gas pipe 45, and the EGR gas introduction passage 62 to the first intake passage 41, particularly An EGR gas introduction port (EGR gas introduction port) 63 for introducing EGR gas into the junction 49 is formed.
Here, the swirling flow generating device 7 of the present embodiment is configured by an EGR gas introduction flow path 62 and the like formed in the EGR introduction pipe 61. The EGR gas introduction channel 62 is a fluid introduction channel that introduces EGR gas in the tangential direction of the wall surface of the first intake duct 4. The EGR gas introduction flow path 62 is curved in an arc shape along the straight portion (straight flow path) 64 that extends straight in the tangential direction of the wall surface of the first intake duct 4 and the wall surface of the first intake duct 4. A curved portion (curved channel) 65 extending in the circumferential direction of the one intake duct 4 is provided.

  As described above, in the EGR system of this embodiment, particularly the LPL-EGR system, the EGR gas introduction flow path 62 formed in the EGR introduction pipe 61 is extended in the tangential direction of the wall surface of the first intake duct 4. Yes. Thereby, the EGR gas introduced into the first intake passage 41 from the EGR gas recirculation passage 46 of the EGR gas pipe 45 via the EGR gas introduction passage 62 enters the first intake passage 41 from the EGR gas introduction port 63. When it flows out, it turns in the circumferential direction of the first intake passage 41 along the wall surface of the first intake duct 4. Due to the swirling flow of the EGR gas formed in the first intake passage 41, the foreign substances contained in the EGR gas are separated from the EGR gas by utilizing the centrifugal force.

Here, instead of the swirl flow generator 7 of the first embodiment, that is, the plurality of fixed swirl blades 56, the swirl flow generator 7 of the present embodiment may be employed.
In the present embodiment, the EGR gas introduction flow for introducing EGR gas in the tangential direction of the wall surface of the first intake duct 4 as the fluid introduction flow path for introducing the fluid into the first intake passage 41 upstream of the compressor. Although the passage 62 is adopted, as the fluid introduction passage, intake air (fresh air) is tangential to the wall surface of the first intake duct 4 that introduces fluid into the first intake passage 41 upstream of the compressor. You may employ | adopt the fluid introduction flow path which introduces the fluid (mixed fluid) which mixed EGR gas.

FIG. 5 shows a third embodiment of the present invention, and FIG. 5 shows a swirling flow generator.
The intake pipe of the present embodiment has a swirling flow generator 7 provided integrally with a cylindrical first intake duct 4 connected to an inlet 31 of a compressor housing 26 of a turbocharger. Foreign matter separation that separates foreign matter (for example, carbon fine particles, condensed water, icing, debris caused by breakage of DPF 21) from the fluid in which EGR gas and intake air are mixed using the centrifugal force of the swirling flow generated by the device 7 Equipment.

The swirling flow generator 7 generates a spiral swirling flow that spirally swirls along the wall surface (cylindrical inner surface) of the first intake duct 4 in the flow of fluid such as EGR gas flowing through the first intake passage 41. The swirling flow generating means is configured.
Here, the first intake duct 4 constituting the swirling flow generating device 7 constitutes a casing of the foreign matter separating device, and the first intake passage 41, particularly the intake air and EGR, upstream of the scroll chamber 29 of the compressor housing 26. It is installed so as to surround the periphery of the junction 49 with the gas.

The first intake duct 4 is formed with a first fluid introduction pipe 66 connected to the downstream end of the air cleaner hose 2 on the air cleaner side extending from the air cleaner case of the air cleaner 1. Further, a second fluid introduction pipe 67 connected to the downstream end of the EGR gas pipe 45 is formed in the first intake duct 4.
Here, the swirling flow generating device 7 of the present embodiment includes a first fluid introduction channel 71 for introducing intake air (fresh air) in a tangential direction of the wall surface of the first intake duct 4, and the wall surface of the first intake duct 4. The second fluid introduction channel 72 for introducing the EGR gas in the tangential direction is provided.

The first fluid introduction channel 71 is curved in an arc shape along the first straight portion (straight channel) 73 that extends straight in the tangential direction of the wall surface of the first intake duct 4 and the wall surface of the first intake duct 4. The first intake duct 4 has first curved portions (curved flow paths) 74 and 75 extending in the circumferential direction. The first straight portion 73 and the first curved portion 74 in the first fluid introduction channel 71 are formed in the first fluid introduction pipe 66.
The second fluid introduction channel 72 is curved in an arc shape along the second straight portion (straight channel) 76 that extends straight in the tangential direction of the wall surface of the first intake duct 4 and the wall surface of the first intake duct 4. The first intake duct 4 has second curved portions (curved flow paths) 77 and 78 extending in the circumferential direction. The second straight portion 76 and the second curved portion 77 in the second fluid introduction channel 72 are formed in the second fluid introduction pipe 67.

The swirling flow generating device 7 forms a wall surface on the outer side in the bending direction of the first bending portion 74, and extends in the bending direction of the first outer wall 81 and the second bending portion 77 extending in the circumferential direction of the first intake duct 4. A second outer wall 82 extending in the circumferential direction of the first intake duct 4, a wall surface on the inner side in the bending direction of the first bending portion 74, and extending in the circumferential direction of the first intake duct 4. A first inner wall 83 and a second inner wall 84 that forms the inner wall surface in the bending direction of the second bending portion 77 and extends in the circumferential direction of the first intake duct 4 are provided.
The first inner wall 83 has a smaller radius of curvature than the first outer wall 81 and the second outer wall 82. In the first inner wall 83, the wall surface on the opposite side to the inner wall surface in the bending direction of the first bending portion 74 is the outer wall surface in the bending direction of the second bending portion 78. The outer wall surface in the bending direction is smoothly connected to the wall surface of the first intake duct 4.

The second inner wall 84 has a smaller radius of curvature than the first outer wall 81 and the second outer wall 82. In the second inner wall 84, the wall surface on the opposite side to the inner wall surface in the bending direction of the second bending portion 77 is the outer wall surface in the bending direction of the first bending portion 75. The outer wall surface in the bending direction is smoothly connected to the wall surface of the first intake duct 4.
As described above, the first fluid introduction channel 71 is formed such that the curvature radii of the first curved portions 74 and 75 become smaller stepwise or continuously toward the downstream side in the intake flow direction. The second fluid introduction channel 72 is formed so that the curvature radii of the second curved portions 77 and 78 become smaller stepwise or continuously toward the downstream side in the EGR gas flow direction.

As described above, in the EGR system according to the present embodiment, particularly the LPL-EGR system, the two first and second fluid introduction channels 71 and 72 are extended in the tangential direction of the wall surface of the first intake duct 4. In addition, the radius of curvature becomes smaller toward the center of the first intake passage 41.
As a result, the intake air and EGR gas introduced into the merge portion 49 of the first intake passage 41 from the two first and second fluid introduction channels 71 and 72 are along the wall surface of the first intake duct 4. The first intake passage 41 turns in the circumferential direction. At this time, since the radius of curvature becomes tighter as the two first and second fluid introduction passages 71 and 72 move toward the center of the first intake passage 41, the centrifugal force of the swirling flow is used in the first and second embodiments. You can earn (strengthen) than. Further, since the first outer wall 81 and the first inner wall 83 on the intake air side and the second outer wall 82 and the second inner wall 84 on the EGR gas side are efficiently used, the intake air and the EGR gas are mixed well. The duct material required to form the possible junction 49 can be reduced.
Here, instead of the swirl flow generator 7 of the first embodiment, that is, the plurality of fixed swirl blades 56, the swirl flow generator 7 of the present embodiment may be employed.

FIGS. 6 to 8 show a fourth embodiment of the present invention. FIG. 6 shows an engine control system. FIGS. 7 and 8 show the main part of the LPL-EGR system.
The intake pipe of the present embodiment includes a first intake duct 4 in which a first intake passage 41 is formed, a second intake duct 5 in which a second intake passage 42 is formed, and a third intake passage in the interior. 43, a foreign matter separating device having a swirling flow generating device 7 of any one of the first to third embodiments, and a foreign matter having an ejector 8, a bypass passage 12 and a check valve 13. And a discharge device.

The 1st intake duct 4 comprises the casing of a foreign material separation apparatus. At the downstream end of the first intake duct 4 is formed a cylindrical inlet connection (joint) that is hermetically connected to the duct connection of the inlet 31 of the compressor housing 26 of the turbocharger. .
At the upstream end of the second intake duct 5, a cylindrical outlet connection (joint) is formed that is hermetically connected to a duct connection of an outlet (not shown) of the compressor housing 26 of the turbocharger. Has been. A main duct 91 and a bypass duct 92 are provided at the downstream end of the second intake duct 5.

At the downstream end of the main duct 91, a cooler connection portion (joint portion) that is hermetically connected to a duct connection portion (inlet tank portion) of the intercooler 9 is formed. Inside the main duct 91 is formed a second intake passage (main flow path 93) that guides the high-pressure fluid pressurized by the compressor of the turbocharger to the inlet tank portion of the intercooler 9.
In addition, an ejector connection portion (joint portion) that is hermetically connected to an ejector inlet portion (inlet port) of the ejector 8 is formed at the downstream end portion of the bypass duct 92. Inside the bypass duct 92 is formed a second intake passage (branch passage 94) that guides the high-pressure fluid pressurized by the compressor to the nozzle 15 of the ejector 8 by bypassing (bypassing) the intercooler 9. .

A main duct 95 and a bypass duct 96 are provided at the upstream end of the third intake duct 6.
At the upstream end of the main duct 95, a cooler connection portion (joint portion) that is hermetically connected to a duct connection portion (exit tank portion) of the intercooler 9 is formed. Inside the main duct 95 is formed a third intake passage (main flow path 97) for guiding the high-pressure fluid flowing out from the intercooler 9 to the intake port and the combustion chamber of each cylinder of the engine body E.
In addition, an ejector connection portion (joint portion) that is hermetically connected to an ejector outlet portion (discharge port) of the ejector 8 is formed at the upstream end portion of the bypass duct 96. Inside the bypass duct 96, a third intake passage (merging passage 98) is formed that guides the high-pressure fluid mixed with foreign matter flowing out from the ejector 8 to the intake port and the combustion chamber of each cylinder of the engine body E. Yes.

  The ejector 8 of this embodiment is connected in parallel to the intercooler 9. The ejector inlet portion of the ejector 8 is airtightly connected to a bypass duct 92 that forms a branch flow path 94 branched from the second intake passage 42 of the second intake duct 5. Further, the ejector outlet portion of the ejector 8 is airtightly connected to a bypass duct 96 that forms a merged flow path 98 that merges with the third intake passage 43 of the third intake duct 6.

Here, the ejector 8 has a negative pressure generating portion 17 that generates a negative pressure acting on the bypass flow path 12 by a differential pressure generated before and after the intercooler 9. Thereby, the foreign material discharging apparatus of the present embodiment can obtain a flow rate required for the ejector 8 using the pressure difference before and after the intercooler 9. Since the throttle portion 16 of the ejector 8 has a larger pressure loss than the intercooler 9, the high-pressure fluid pressurized by the compressor of the turbocharger is used in the axial flow path (nozzle 15, throttle) of the ejector 8. It flows more towards the intercooler 9 than the part 16, the mixing part 18 and the diffuser 19).
The intercooler 9 includes a plurality of tubes between the inlet tank portion and the outlet tank portion. The inlet tank portion, the outlet tank portion, and each tube are made of a metal material such as an aluminum alloy.

  As described above, in the EGR system of this embodiment, particularly the LPL-EGR system, foreign matter such as strongly acidic condensed water separated from the fluid in which the EGR gas and the intake air are mixed by the foreign matter separation device is discharged outside the vehicle. Without any problem, even if the vehicle such as an automobile is stopped, the road surface is partially maintained because the high-pressure fluid pressurized by the compressor of the turbocharger can be guided to the intake port and the combustion chamber for each cylinder of the engine body E. Occurrence of defects such as discoloration can be suppressed. Further, foreign matter such as strongly acidic condensed water collected in a tank 52 provided at the downstream end of the first intake duct 4 is guided to the ejector 8 by bypassing the compressor housing 26 of the turbocharger. Therefore, corrosion of the compressor (particularly the compressor housing 26) and the intercooler 9 made of a metal material such as an aluminum alloy can be suppressed.

  Also, the action of the ejector 8 creates a flow in which foreign matter is actively sent downstream from the scroll chamber 29 of the compressor housing 26, and the foreign matter separated from the fluid in which EGR gas and intake air are mixed is sucked by the foreign matter separation device. Can be quickly discharged from the first intake duct 4. Thereby, the foreign material separated from the fluid in the foreign material separation apparatus can be quickly discharged from the first intake duct 4 without requiring a new power source. Therefore, since the foreign matter separated from the fluid by the foreign matter separation device can be prevented from being mixed again in the fluid due to staying in the first intake duct 4 for a long time, the foreign matter separation efficiency can be improved.

  Further, since the foreign matter can be efficiently separated (centrifugated) from the fluid in which the EGR gas and the intake air are mixed by the foreign matter separation device, for example, foreign matter such as carbon fine particles, condensed water, freezing, debris caused by breakage of the DPF 21, etc. It is possible to allow a fluid that does not substantially contain the gas to flow into the scroll chamber 29 formed in the compressor housing 26 of the turbocharger, that is, the scroll chamber 29 that rotatably accommodates the compressor impeller 25. As a result, it is possible to suppress breakage and wear of the compressor impeller 25 due to collision of foreign matter contained in the EGR gas introduced into the first intake passage 41 of the first intake duct 4.

FIG. 9 shows a fifth embodiment of the present invention, and FIG. 9 is a diagram showing a main part of the LPL-EGR system.
The intake pipe of the present embodiment includes a first intake duct 4 in which a first intake passage 41 is formed, a second intake duct 5 in which a second intake passage 42 is formed, and the first to third embodiments. A foreign matter separating device having any one of the swirling flow generating devices 7 and a foreign matter discharging device having an ejector 8, a bypass flow path 12 and a check valve 13 are provided.
The 1st intake duct 4 comprises the casing of a foreign material separation apparatus. At the downstream end of the first intake duct 4 is formed a cylindrical inlet connection (joint) that is hermetically connected to the duct connection of the inlet 31 of the compressor housing 26 of the turbocharger. .

At the upstream end of the second intake duct 5, a cylindrical outlet connecting portion (joining portion) that is hermetically connected to the duct connecting portion of the outlet 33 of the compressor housing 26 of the turbocharger is formed. In addition, a cooler connection portion (joint portion) that is hermetically connected to a duct connection portion (inlet tank portion) of the intercooler 9 is formed at the downstream end portion of the second intake duct 5. A second intake passage 42 through which high-pressure fluid pressurized by a compressor of the turbocharger flows is formed inside the second intake duct 5.
As shown in FIG. 9, the second intake passage 42 of the second intake duct 5 has a cylindrical fluid flow path 44 formed around the ejector 8 so that the high-pressure fluid passes around the ejector 8. have. As a result, the high-pressure fluid pressurized by the compressor of the turbocharger passes through the cylindrical fluid flow path 44 in the second intake passage 42 upstream of the ejector 8 in the intake flow direction. The flow branches into a flow and a flow of high-pressure fluid passing through the inside of the ejector 8 (axial flow path). That is, a part of the high-pressure fluid pressurized by the compressor passes through the cylindrical fluid flow path 44 toward the intake port side of each cylinder of the engine body E. Further, the remainder of the high-pressure fluid pressurized by the compressor passes through the inside of the ejector 8 (axial flow path: nozzle 15, mixing unit 18 and diffuser 19) to the intake port side of each cylinder of the engine body E. Head.

  The ejector 8 of the present embodiment is disposed in the second intake passage 42 of the second intake duct 5. In this case, when the high pressure fluid pressurized by the compressor of the turbocharger flows through the nozzle 15 of the ejector 8 and the high pressure fluid is ejected from the throttle portion 16 of the nozzle 15, the negative pressure generating portion 17 of the ejector 8 is supplied. A negative pressure (negative pressure suction force for sucking foreign matter collected or accumulated in the tank 52 through the bypass passage 12) acting on the bypass passage 12 is generated. As a result, the foreign matter separated by the foreign matter separation device is sucked from the foreign matter separation device through the bypass flow path 12 and the suction port 14 to the negative pressure generating unit 17. The foreign matter sucked into the ejector 8 is mixed into the high-pressure fluid pressurized by the compressor in the mixing unit 18, passes through the diffuser 19, and is ejected from the ejector outlet (discharge port) of the second intake duct 5. The fuel is discharged into the second intake passage 42 (second intake passage 42 on the downstream side in the intake air flow direction from the ejector 8). The high-pressure fluid mixed with foreign matter discharged into the second intake passage 42 of the second intake duct 5 (the second intake passage 42 downstream of the ejector 8 in the intake flow direction) passes through the fluid passage 44. After being mixed into the high-pressure fluid, it is guided to the intake port and the combustion chamber for each cylinder of the engine body E.

Here, when the ejector 8 is disposed in the second intake passage 42 of the second intake duct 5 connected to the outlet 33 of the compressor housing 26 of the turbocharger, the high pressure fluid pressurized by the compressor of the turbocharger. There is a possibility that a large pressure loss occurs and the intake air amount necessary for operating the engine body E cannot be obtained.
Therefore, as shown in FIG. 9, the second intake passage 42 of the second intake duct 5 of this embodiment has a cross-sectional area of a cylindrical fluid passage 44 formed around the ejector 8 as a compressor. The cross-sectional area of the second intake passage 42 of the second intake duct 5 is smoothly enlarged upstream of the ejector inlet portion (inlet port) of the ejector 8 so that the opening diameter of the outlet 33 of the housing 26 is equal to or larger than the opening diameter. is doing. As a result, even when the ejector 8 is disposed in the second intake passage 42 of the second intake duct 5, the high pressure fluid that is pressurized by the compressor of the turbocharger and flows through the second intake passage 42. The generated pressure loss can be reduced.
As described above, in the EGR system of the present embodiment, in particular, the LPL-EGR system, the same operational effects as those of the first embodiment can be obtained.

FIG. 10 shows a sixth embodiment of the present invention, and FIG. 10 is a view showing the main part of the foreign matter separating apparatus.
The intake pipe of this embodiment includes a cylindrical first intake duct 4 in which a first intake passage 41 is formed, a second intake duct 5 in which a second intake passage 42 is formed, and a first intake. A foreign matter separation device that separates foreign matter contained in a fluid (mixed fluid obtained by mixing EGR gas and intake air) flowing through the first intake passage 41 of the duct 4 from the fluid, and the foreign matter separation device separated the fluid from the fluid. A foreign matter discharge device is provided that guides foreign matter to the intake port and the combustion chamber of each cylinder of the engine body E by bypassing the scroll chamber 29 of the compressor housing 26 of the turbocharger.
The foreign matter separating apparatus according to the present embodiment generates a swirl flow generator that generates a swirl flow swirling along the wall surface of the first intake duct 4 in the flow of the fluid flowing in the first intake passage 41 of the first intake duct 4. 7 (the swirl flow generator 7 in any one of the first to third embodiments). The first intake duct 4 is provided with a foreign matter collecting section that collects foreign matter separated from the fluid, which is guided to the outer peripheral portion of the swirling flow by the centrifugal force of the swirling flow generated by the swirling flow generating device 7. Not.

Here, at the downstream end portion of the first intake duct 4 of the present embodiment, a cylindrical inlet connection portion (joint portion) that is hermetically connected to the duct connection portion of the inlet 31 of the compressor housing 26 of the turbocharger. ) Is formed. A bypass flow path 12 is connected to the vicinity of the inlet connecting portion of the first intake duct 4 via a slit (foreign matter discharging portion) 11.
The foreign matter discharging apparatus of the present embodiment includes an ejector 8 that generates a negative pressure by the flow of a high-pressure fluid pressurized by a compressor, a slit 11 that opens near the inlet connection portion of the first intake duct 4, and a suction port of the ejector 8. 14 is provided with a bypass passage 12 that bypasses and connects the scroll chamber 29 of the compressor housing 26.
The slit 11 is opened at the cylindrical inner surface (wall surface) of the first intake duct 4 on the downstream side of the swirling flow generator 7 in the intake flow direction. The slit 11 is a single-letter opening that extends straight in a direction parallel to the central axis of the first intake passage 41 (extension direction of the first intake duct 4). Further, as in the first to fifth embodiments, a high-pressure fluid pressurized by a compressor of the turbocharger (high-pressure fluid mixed with foreign matter or negative pressure generating portion 17 of the ejector 8) is sucked into the bypass passage 12 in the middle. The check valve 13 may be installed to prevent the backflow of the generated foreign matter).

As described above, in the EGR system of this embodiment, particularly the LPL-EGR system, the centrifugal force acts on the foreign matter contained in the EGR gas by the swirling flow generated by the swirling flow generating device 7, and the foreign matter is the outer periphery of the swirling flow. To the outer periphery of the first intake passage 41. And the foreign material which was guide | induced to the outer peripheral part of the swirling flow generated with the swirling flow generator 7 and isolate | separated from the fluid swirls along the wall surface (cylindrical inner surface) of the inlet connection part vicinity of the 1st intake duct 4. FIG. The turning foreign matter is sucked into the negative pressure generating portion 17 of the ejector 8 from the slit 11 through the bypass flow path 12, and further mixed into the high-pressure fluid pressurized by the compressor. To the intake port and combustion chamber.
Therefore, the same effect as Example 1 can be obtained.

  In the present embodiment, the foreign matter centrifuged by the swirling flow generated by the swirling flow generating device 7 is sucked by the negative pressure suction force generated by the negative pressure generating portion 17 of the ejector 8, so that the first intake The opening position of the slit 11 opened at the wall surface (cylindrical inner surface) in the vicinity of the inlet connection portion of the duct 4 does not need to be the lowest part in the gravitational direction (the vehicle vertical direction) in the first intake passage 41, and the first intake duct 4 The slit 11 may be opened at any location in the circumferential direction of the cylindrical portion (the direction in which the periphery of the central axis of the first intake passage 41 is surrounded in the circumferential direction).

FIG. 11 shows Embodiment 7 of the present invention, and FIG. 11 is a view showing the main part of the foreign matter separating apparatus.
At the downstream end of the first intake duct 4 of the present embodiment, a guide plate 99 that guides foreign matter led to the outer periphery of the swirling flow generated by the swirling flow generating device 7 to the slit 11 is installed. The guide plate 99 protrudes inward from the cylindrical inner surface (wall surface) of the first intake duct 4 so as to face the swirl direction of the foreign matter guided to the outer periphery of the swirl flow generated by the swirl flow generator 7. .

As described above, in the EGR system of the present embodiment, particularly the LPL-EGR system, in addition to the structure of the sixth embodiment, the guide plate 99 is provided on the upper portion of the slit 11, so that the swirl flow generator 7 generates the guide plate 99. The discharge efficiency of the foreign matters centrifuged by the swirling flow can be increased.
Since the guide plate 99 is provided in the vicinity of the slit 11 so as to face the rotational direction of the fluid generated by the swirling flow generated by the swirling flow generating device 7, foreign matter introduced to the outer peripheral portion of the swirling flow generated by the swirling flow generating device 7 Collides with the guide plate 99 and is efficiently separated from the fluid. Further, by disposing the guide plate 99 in a direction perpendicular to the rotation axis direction (intake flow direction) of the compressor impeller 25 of the turbocharger, the pressure loss of the intake air including EGR gas can be suppressed.

[Modification]
In the present embodiment, the cylindrical inner surface of the first intake duct 4 (the EGR gas alone may be flowed) in the flow of the fluid (or only EGR gas) flowing through the first intake passage 41 upstream of the scroll chamber 29 of the compressor housing 26 of the turbocharger. A swirl flow generator 7 is provided in the first intake duct 4 for generating a spiral swirl flow spirally along the wall surface and centrifuging foreign matter from the fluid by the swirl flow. The generator 7 may be provided in the EGR gas pipe 45 so that the swirling flow of EGR gas is introduced into the first intake passage 41 upstream of the scroll chamber 29 of the compressor housing 26 of the turbocharger.
A gasoline engine may be used as the internal combustion engine (engine body E). Further, as the internal combustion engine (engine body E), not only a multi-cylinder engine but also a single-cylinder engine may be used.

  In this embodiment, as a supercharger, a turbocharger that supercharges intake air sucked into a combustion chamber for each cylinder of the engine body E using the exhaust energy of the internal combustion engine (engine body E). Although an example in which a turbocharger is employed has been described, a turbocharger (turbocharger) with an assist motor that rotationally drives the rotating shaft (rotor shaft 27) of the turbocharger may be employed as a turbocharger. good. Or you may employ | adopt the supercharger with a motor (supercharger) which supercharges the intake air suck | inhaled in the combustion chamber for every cylinder of an internal combustion engine (engine main body E) using the drive torque of a motor. Moreover, you may use the electric compressor which comprised the supercharger only with the compressor as a supercharger.

In the present embodiment, the high-pressure EGR cooler 37 is installed in the middle of the EGR gas pipe 35, but a bypass pipe that bypasses the high-pressure EGR cooler 37 may be connected in the middle of the EGR gas pipe 35. In this case, you may install the flow-path switching valve which opens and closes the EGR gas recirculation path formed in bypass piping.
In the present embodiment, the low pressure EGR cooler 47 is installed in the middle of the EGR gas pipe 45, but a bypass pipe that bypasses the low pressure EGR cooler 47 may be connected in the middle of the EGR gas pipe 45. In this case, you may install the flow-path switching valve which opens and closes the EGR gas recirculation path formed in bypass piping.

  In this embodiment, as the foreign matter separating means, a spiral swirling flow that spirally swirls along the wall surface of the outer pipe 51 is generated in the flow of the fluid flowing in the first intake passage 41 of the first intake duct 4. A swirling flow generating device (swirl flow generating means) 7 is provided. As a foreign matter separating means, a filter or the like that captures foreign matter in a fluid obtained by mixing exhaust gas (EGR gas) and air and separates it from the fluid. Foreign matter separating means may be employed. For example, a sheet-like mesh filter may be used.

E Engine body (internal combustion engine)
4 First intake duct (first duct)
5 Second intake duct (second duct)
6 Third intake duct (second duct)
7 Swirling flow generator (foreign matter separating means, swirling flow generating means)
8 Ejector (Foreign matter discharging means)
9 Intercooler 11 Slit (Foreign matter discharge means, foreign matter discharge part)
12 Bypass channel (foreign matter discharging means)
13 Check valve (means for discharging foreign matter)
14 Ejector suction port 15 Ejector nozzle (foreign matter discharging means)
16 Nozzle throttling part 17 Ejector negative pressure generating part (foreign matter discharging means)
18 Ejector mixing part (foreign matter discharging means)
19 Ejector diffuser
25 Compressor impeller 26 Compressor housing 27 Rotor shaft (rotating shaft)
29 Scroll chamber 31 Inlet 33 Outlet 41 First intake passage of the first intake duct 42 Second intake passage of the second intake duct 44 Fluid flow path 45 EGR gas pipe (exhaust gas recirculation pipe)
48 Low pressure EGR flow control valve (exhaust gas control valve)
51 outer pipe 52 tank (foreign matter collecting part)
53 Inner pipe 54 Foreign matter storage space (foreign matter collection part, cylindrical space)

Claims (15)

A supercharger having a compressor for feeding high pressure fluid to the internal combustion engine;
An intake pipe having a first intake passage provided upstream of the compressor in the fluid flow direction and a second intake passage provided downstream of the compressor in the fluid flow direction;
An exhaust gas recirculation apparatus for an internal combustion engine, comprising an exhaust gas recirculation pipe for recirculating exhaust gas discharged from the internal combustion engine into the first intake passage.
The intake pipe is
A first duct that is disposed so as to surround the first intake passage in the circumferential direction, and that guides a fluid that is a mixture of exhaust gas and air introduced from the exhaust gas recirculation pipe to the compressor; and the second intake air A second duct that is installed so as to surround the periphery of the passage in the circumferential direction and guides the high-pressure fluid pressurized by the compressor to the internal combustion engine;
Foreign matter separating means disposed in the first duct for separating foreign matter contained in the fluid flowing through the first duct from the fluid;
An exhaust gas recirculation device for an internal combustion engine, comprising: foreign matter discharge means for guiding foreign matter separated from the fluid in the first duct to the internal combustion engine by bypassing the compressor. The exhaust gas recirculation device for an internal combustion engine according to claim 1,
The foreign matter discharging means bypasses the compressor with the ejector that mixes the foreign matter separated from the fluid in the first duct into the high-pressure fluid pressurized by the compressor, and the foreign matter separated from the fluid in the first duct. An exhaust gas recirculation device for an internal combustion engine comprising a bypass flow path that leads to the ejector. The exhaust gas recirculation device for an internal combustion engine according to claim 2,
The exhaust gas recirculation device for an internal combustion engine, wherein the foreign matter discharging means has a negative pressure generating portion that generates a negative pressure acting on the bypass flow path by a differential pressure generated before and after the ejector. The exhaust gas recirculation device for an internal combustion engine according to claim 2 or 3,
The compressor has an impeller that rotates about a rotation axis, a scroll chamber that rotatably accommodates the impeller, and an outlet that allows high-pressure fluid to flow out from the scroll chamber.
The exhaust gas recirculation device for an internal combustion engine, wherein the ejector is disposed between an outlet of the compressor and the second duct. The exhaust gas recirculation device for an internal combustion engine according to claim 2 or 3,
The exhaust gas recirculation apparatus for an internal combustion engine, wherein the ejector is disposed in the second duct. The exhaust gas recirculation device for an internal combustion engine according to claim 5,
The exhaust gas recirculation apparatus for an internal combustion engine, wherein the second intake passage has a cylindrical fluid flow path through which a high-pressure fluid pressurized by the compressor flows around the ejector. The exhaust gas recirculation device for an internal combustion engine according to claim 6,
The compressor has an impeller that rotates about a rotation axis, a scroll chamber that rotatably accommodates the impeller, and an outlet that allows high-pressure fluid to flow out from the scroll chamber.
The second intake passage has a passage sectional area of the second intake passage upstream of the ejector so that a passage sectional area of the fluid passage is equal to or larger than an opening diameter of an outlet of the compressor. An exhaust gas recirculation device for an internal combustion engine, which is smoothly expanded. The exhaust gas recirculation device for an internal combustion engine according to any one of claims 2 to 4,
The second duct includes an intercooler that cools the high-pressure fluid pressurized by the compressor,
The ejector is connected in parallel to the intercooler,
The exhaust gas recirculation apparatus for an internal combustion engine, wherein the bypass channel guides foreign matter separated from the fluid in the first duct to the ejector by bypassing the intercooler. The exhaust gas recirculation device for an internal combustion engine according to claim 8,
The exhaust gas recirculation device for an internal combustion engine, wherein the foreign matter discharging means has a negative pressure generating portion that generates a negative pressure acting on the bypass flow path by a differential pressure generated before and after the intercooler. . The exhaust gas recirculation device for an internal combustion engine according to any one of claims 1 to 9,
The internal combustion engine characterized in that the foreign matter separating means has a swirl flow generating means for generating a swirl flow swirling along the wall surface of the first duct in the flow of fluid flowing through the first duct. Exhaust gas recirculation device. The exhaust gas recirculation device for an internal combustion engine according to any one of claims 1 to 10,
The exhaust gas recirculation device for an internal combustion engine, wherein the foreign matter separating means has a foreign matter collecting portion for collecting the foreign matter separated from the fluid in the first duct. The exhaust gas recirculation device for an internal combustion engine according to claim 11,
The exhaust gas recirculation device for an internal combustion engine, wherein the foreign matter collecting section includes a tank for collecting foreign matter separated from the fluid in the first duct. The exhaust gas recirculation device for an internal combustion engine according to any one of claims 1 to 12,
An exhaust gas recirculation apparatus for an internal combustion engine, comprising an exhaust gas control valve for adjusting a flow rate of exhaust gas flowing through the exhaust gas recirculation pipe. The exhaust gas recirculation device for an internal combustion engine according to any one of claims 1 to 13,
The exhaust gas recirculation apparatus for an internal combustion engine, wherein the second duct includes an intercooler that cools the high-pressure fluid pressurized by the compressor. The exhaust gas recirculation device for an internal combustion engine according to any one of claims 1 to 14,
The compressor has an impeller that rotates about a rotation shaft, a scroll chamber that rotatably accommodates the impeller, an inlet that allows fluid to flow into the scroll chamber, and an outlet that allows fluid to flow out of the scroll chamber. An exhaust gas recirculation device for an internal combustion engine.

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