JP2007127070A - Supercharged internal combustion engine - Google Patents

Abstract

An internal combustion engine with a supercharger in which the content of particulates in exhaust gas does not increase during transient operation.
In an internal combustion engine with a supercharger, an exhaust manifold 6 of an engine 1 and an intake pipe 12 are connected by an EGR pipe line 21, and an intake air A is introduced in the vicinity of the upstream side of the EGR pipe 21 merging point of the intake pipe 12. A blower 23 that can be pumped is incorporated in parallel, and a bypass automatic valve 24 that closes with intake air A delivered from the blower 23 is provided in a portion parallel to the blower 23 of the intake pipe 12.
That is, the blower 23 is operated during the transient operation of the engine 1, the bypass automatic valve 24 is closed by the pressure of the intake air A sent from the blower 23, and the exhaust gas G returning from the EGR pipe line 21 to the intake pipe 12 path is suppressed. The amount of intake air A to be delivered to 1 is secured.
[Selection] Figure 1

Description

  The present invention relates to a supercharged internal combustion engine equipped with an EGR device.

  Conventionally, in an internal combustion engine with a supercharger to which exhaust gas recirculation (EGR) is applied, exhaust gas diverted from the engine exhaust path is sent to the engine intake path to lower the combustion temperature, thereby generating NOx. (For example, refer to Patent Document 1).

  The supercharged internal combustion engine includes a diesel engine 1 and a turbocharger 2 as shown in FIGS. 3 and 4, and the turbocharger 2 connects the turbine 3, the compressor 4, and the turbine impeller to the compressor impeller. The transmission shaft 5 is configured.

  The turbine 3 has an exhaust introduction port connected to the exhaust manifold 6 of the diesel engine 1, an exhaust delivery port communicates with the muffler 8 through the exhaust pipe 7, and a flow path cross-sectional adjustment mechanism (not shown) is connected to the exhaust introduction port. ) Is provided.

  The compressor 4 has an intake inlet connected to an air cleaner 10 via an intake pipe 9 and an intake outlet connected to an intake manifold 13 of the diesel engine 1 via an intake pipe 12 having an intercooler 11.

  In addition to this, an upstream end of an EGR pipe line 16 in which an EGR cooler 14 and an EGR valve 15 are incorporated in series is connected to the exhaust manifold 6, and the EGR pipe line 16 is connected to a location downstream of the intercooler 11 of the intake pipe 12. Is connected to the downstream end.

  The intercooler 11 is an air-cooled fin-type heat exchanger, and the EGR cooler 14 is a liquid-cooled tubular heat exchanger.

  Further, an on-off valve 17 is incorporated downstream of the connection portion of the intake pipe 12 with respect to the EGR conduit 16, and the upstream end of the air supply conduit 18 is connected between the connection portion of the intake pipe 12 with the EGR conduit 16 and the outlet of the intercooler 11. The downstream end of the air supply line 18 is connected between the position where the on-off valve 17 of the intake pipe 12 is installed and the intake manifold 13, and a blower 19 using a motor 20 as a drive source is incorporated in the air supply line 18.

  During steady operation of the diesel engine 1, the blower 19 is stopped and the on-off valve 17 is opened as shown in FIG.

  Most of the exhaust G from the diesel engine 1 flows into the turbine 3 from the exhaust manifold 6 to drive the compressor 4 and is discharged into the atmosphere through the exhaust pipe 7 and the muffler 8.

  The compressed air A that flows into the compressor 4 through the air cleaner 10 and the intake pipe 9 and is compressed passes through the intercooler 11 and then is supplied to the intake manifold 13 without passing through the air supply pipe 18 having a large flow resistance.

  At the same time, a part of the exhaust G flows from the exhaust manifold 6 into the EGR pipe 16, and the exhaust G cooled by the EGR cooler 14 and adjusted in flow rate by the EGR valve 15 is sent to the intake manifold 13 together with the intake air A. Is done.

  As a result, the combustion temperature is lowered and the generation of NOx is reduced.

  Since the turbocharger 2 drives the compressor 4 by the turbine 3 that is rotated by the energy of the exhaust G, when the driver depresses the accelerator petal and increases the engine speed (transient operation), the compressor 4 The increase in the discharge amount of the intake air A is delayed.

  During such a transient operation, the kinetic energy that the turbine 3 obtains from the exhaust G decreases, so that the intake air A that is supplied from the compressor 4 to the intake manifold 13 becomes insufficient, and is consequently sent from the diesel engine 1. The particulates contained in the exhaust G increase.

  Therefore, during the transient operation of the diesel engine 1, the on-off valve 17 is closed and the blower 19 is operated as shown in FIG.

That is, the amount of intake air A to be supplied to the diesel engine 1 during transient operation by sending the intake air A sent by the compressor 4 to the intake manifold 13 by the blower 19 without depending on the kinetic energy obtained from the exhaust G by the turbine 3. Secure.
JP 2005-220862 A

  However, during the transient operation of the diesel engine 1, it is difficult to instantaneously close the on-off valve 17 and the EGR valve 15 with an actuator so as to cope with changes in the amount of depression of the accelerator. When accelerating from a state where the engine is operated at a high EGR rate, the amount of intake air A is still insufficient, the particulate content increases, and the exhaust gas G deteriorates.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a supercharged internal combustion engine in which the content of particulates in exhaust gas does not increase during transient operation.

  In order to achieve the above object, the present invention provides an internal combustion engine with a supercharger configured to drive a compressor by a turbine rotated by exhaust of the engine and to supply intake air compressed by the compressor to the engine via an intercooler. In the engine, an EGR pipe line extending from the turbine upstream side of the engine exhaust path to the compressor downstream side of the engine intake path is provided, and an air blowing means capable of pressure-feeding the intake air is provided in parallel near the EGR pipe merging point of the engine intake path. And an automatic valve that is closed by the intake air sent from the blower means is provided in a portion parallel to the blower means of the engine intake path.

  In other words, the air blowing means is operated during the transient operation of the engine, and the automatic valve is closed and the exhaust gas recirculated from the EGR pipe to the engine air intake path is suppressed by the pressure of the intake air sent by the air blowing means.

  According to the internal combustion engine with a supercharger of the present invention, the pressure of the intake air sent out by the air blowing means closes the automatic valve and suppresses the exhaust gas recirculated from the EGR pipe line to the engine intake path, and supplies it to the engine during transient operation. Since the amount of intake air that should be secured can be secured, it is possible to achieve an excellent effect that the particulate content in the exhaust gas does not increase and the exhaust gas properties do not deteriorate.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 and 2 show an example of an embodiment of an internal combustion engine with a supercharger according to the present invention. In the figure, the same reference numerals as those in FIGS. 3 and 4 denote the same parts. .

  In this supercharger-equipped internal combustion engine, the exhaust manifold 6 is connected to the upstream end of an EGR pipe 21 in which an EGR cooler 14 and an EGR valve 15 are incorporated in series, and the downstream end of the EGR pipe 21 is connected to the intake pipe 12. The intercooler 11 is connected to a location downstream of the intercooler 11 and close to the intake manifold 13.

  A blower 23 capable of pumping intake air A by using the motor 22 as a drive source is incorporated in parallel in the vicinity of the EGR pipe 21 connection portion of the intake pipe 12 in parallel. The motor 22 changes the amount of depression of the accelerator petal, etc. Based on the above, the ECU (Electonic Control Unit) operates when it recognizes the transient operating state of the diesel engine 1.

  Furthermore, a bypass automatic valve (flapper) 24 that closes with the pressure of the intake air A sent from the blower 23 is provided at a portion parallel to the blower 23 of the intake pipe 12.

  The bypass automatic valve 24 is opened by the pressure of the intake air A sent from the compressor 4 when the blower 23 is stopped.

  During the steady operation of the diesel engine 1, the blower 23 is stopped as shown in FIG. 2, so that most of the exhaust G flows from the exhaust manifold 6 into the turbine 3 to drive the compressor 4, and the exhaust pipe 7 and It is released into the atmosphere through the muffler 8 and the like.

  The intake air A that flows into the compressor 4 through the air cleaner 10 and the intake pipe 9 and is compressed passes through the intercooler 11, and then is supplied to the intake manifold 13 through the intake pipe 12.

  At this time, the bypass automatic valve 24 is opened by the pressure of the intake air A passing through the intake pipe 12.

  At the same time, a part of the exhaust G flows from the exhaust manifold 6 to the EGR pipe 21, and the exhaust G cooled by the EGR cooler 14 and adjusted in flow rate by the EGR valve 15 is sent to the intake manifold 13 together with the intake A. Is done.

  As a result, the combustion temperature is lowered and the generation of NOx is reduced.

  During the transient operation of the diesel engine 1, the blower 23 is operated as shown in FIG. 1, and the pressure at the intake outlet side of the blower 23 is higher than that at the intake inlet side, so the bypass automatic valve 24 is closed.

  As a result, the intake air A that has passed through the compressor 4 is sent to the intake manifold 13 without depending on the kinetic energy that the turbine 3 obtains from the exhaust G, and the amount of intake air A that should be supplied to the diesel engine 1 during the transient operation can be secured.

  Therefore, the content of the particulates contained in the exhaust G does not increase, and the exhaust properties do not deteriorate.

  Note that the supercharged internal combustion engine of the present invention is not limited to the above-described embodiment, and it is needless to say that changes can be made without departing from the scope of the present invention.

  The supercharged internal combustion engine of the present invention can be applied to various internal combustion engines including a diesel engine for vehicles.

It is a conceptual diagram which shows the time of the transient operation of an example of embodiment of the internal combustion engine with a supercharger of this invention. It is a conceptual diagram which shows the time of steady operation of an example of embodiment of the internal combustion engine with a supercharger of this invention. It is a conceptual diagram which shows the time of transient operation of an example of the conventional internal combustion engine with a supercharger. It is a conceptual diagram which shows the time of steady operation of an example of the conventional internal combustion engine with a supercharger.

Explanation of symbols

1 Diesel engine 3 Turbine 4 Compressor 6 Exhaust manifold (engine exhaust path)
12 Intake pipe (engine intake path)
21 EGR line 22 Motor 23 Blower (Blower)
24 Bypass automatic valve A Intake G Exhaust

Claims (2)

  In an internal combustion engine with a supercharger configured to drive a compressor by a turbine rotated by exhaust of an engine and to supply intake air compressed by the compressor to an engine via an intercooler, the engine from the turbine upstream side of the engine exhaust path An EGR pipe that leads to the downstream side of the compressor in the intake path is provided, and a blower that can pump intake air is installed in parallel in the vicinity of the upstream side of the EGR pipe merging point in the engine intake path, and the intake air sent from the blower An internal combustion engine with a supercharger, wherein an automatic valve for closing is provided in a portion parallel to the air blowing means of the engine intake path.   The internal combustion engine with a supercharger according to claim 1, wherein a blower using a motor as a drive source is used as the blowing means.

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