JP2010150961A - Exhaust gas recirculation device - Google Patents

Abstract

The present invention relates to an exhaust gas recirculation device, and an EGR passage is made as short as possible to improve responsiveness to a transition of an engine operating state.
An exhaust gas purification device provided in an exhaust passage for purifying exhaust gas, and an exhaust passage and downstream of the exhaust gas purification device connected to an intake passage are purified by the exhaust gas purification device. An EGR passage 30 that recirculates a part of the exhaust gas as EGR gas to the intake passage 10, an EGR cooler 31 that is provided in the EGR passage 30 to cool the EGR gas, and an EGR passage 30 that is downstream of the EGR cooler 31. In contrast to the exhaust gas recirculation device having the EGR valve 32 for adjusting the amount of EGR gas, the exhaust purification device 26 is installed in the engine room ER so that the outlet thereof is close to the inlet of the EGR cooler 31. The EGR valve 32 is installed so as to be inclined so that the outlet thereof is close to the intake passage 10.
[Selection] Figure 1

Description

  The present invention relates to a layout of each component of an exhaust gas recirculation device [EGR (Exhaust Gas Recirculation) device].

Conventionally, a part of the exhaust gas discharged from the combustion chamber of the diesel engine to the exhaust passage is recirculated to the intake passage through the EGR passage, and the combustion temperature of the air-fuel mixture in the combustion chamber is lowered to reduce the NOx emission amount. A technique related to an exhaust gas recirculation device (EGR device) is known. Such a technique is disclosed in Patent Document 1, for example.
JP 2003-293865 A

By the way, when the engine operating state shifts, the exhaust gas before the transition remains in the EGR passage. For this reason, there is a response delay problem that the longer the EGR passage is, the more the exhaust gas before transition remains in the EGR passage, and it takes more time to replace the exhaust gas after the transition.
If there is such a response delay, for example, when the exhaust gas recirculation is switched from off to on, the exhaust gas in the operating state in the EGR passage that is unknown from the engine is supplied to the engine. Periods may occur and undesirable operating conditions may continue.

  Further, when exhaust gas is enriched in order to regenerate a diesel particulate filter (DPF; Diesel Particulate Filter) as an exhaust gas aftertreatment device, if exhaust gas in a lean state remains in the EGR passage, exhaust gas in the EGR passage The fuel injection amount must be increased until the exhaust gas enriched by the replacement of the exhaust gas into the rich state is mixed into the fresh air. In such a method, in addition to the deterioration of fuel consumption, there arises a problem that the performance of exhaust gas also deteriorates.

  The present invention has been devised in view of such problems, and an object of the present invention is to provide an exhaust gas recirculation device that can shorten the EGR passage as much as possible and improve the response to the transition of the operating state of the engine. And

  In order to achieve the above object, an exhaust gas recirculation device according to the present invention according to claim 1 is provided in an exhaust passage of an engine mounted on a vehicle to purify the exhaust gas of the engine, and the exhaust purification device. An EGR passage that connects the exhaust passage downstream of the engine and the intake passage of the engine and recirculates a part of the exhaust gas purified by the exhaust purification device to the intake passage as EGR gas, and the EGR passage An exhaust gas recirculation apparatus comprising: an EGR cooler that cools the EGR gas; and an EGR valve that is provided in the EGR passage downstream of the EGR cooler and adjusts the amount of the EGR gas, In the engine room of the vehicle in which the engine is installed, the exhaust purification device is installed with an inclination so that its outlet is close to the inlet of the EGR cooler, and the EGR valve It is characterized in that its outlet is installed inclined so as to approach the intake passage. Here, the proximity means that the devices are as close as possible in consideration of the structure of each device and the layout to the engine room. The proximity used below is the same.

  The exhaust gas recirculation device of the present invention according to claim 2 is provided in an exhaust passage of an engine mounted on a vehicle to purify the exhaust gas of the engine, and the exhaust purification device downstream of the exhaust purification device. An EGR passage that connects the exhaust passage and the intake passage of the engine and recirculates a part of the exhaust gas purified by the exhaust purification device to the intake passage as EGR gas, and is provided in the EGR passage. An exhaust gas recirculation device comprising an EGR cooler that cools the engine and an EGR valve that is provided in the EGR passage and adjusts the amount of the EGR gas, in the engine room of the vehicle in which the engine is installed, The exhaust emission control device is installed with an inclination so that its outlet is close to the inlet of the EGR cooler, and the EGR cooler is inclined so that its outlet is close to the intake passage. It is characterized in that it is location.

In the exhaust gas recirculation device according to the second aspect of the present invention, it is preferable that the EGR valve is also inclined and installed in the engine room so that the outlet thereof is close to the intake passage (Claim 3). Further, it is preferable that the EGR valve is provided in the EGR passage on the downstream side of the EGR cooler (claim 4).
Further, in the exhaust gas recirculation device according to claim 1 or 2, the turbine provided in the exhaust passage and driven by the flow of exhaust gas, and provided in the intake passage and coaxially connected to the turbine. It is preferable to further comprise a supercharger comprising a compressor. In the engine room, the EGR valve is preferably installed side by side in the horizontal direction with the EGR cooler, or installed side by side in the vertical direction with the EGR cooler. ). Preferably, the vehicle is a four-wheel drive vehicle, and the engine is installed such that its crankshaft extends in the vehicle width direction, that is, is placed horizontally (claim 8).

  According to the exhaust gas recirculation device of the first aspect of the present invention, in the engine room, the exhaust gas purification device is installed to be inclined so that the outlet thereof is close to the inlet of the EGR cooler, and the EGR valve is connected to the outlet of the exhaust gas recirculation device. Since it is installed so as to be close to the intake passage, the EGR passage can be made as short as possible. As a result, the EGR gas remaining in the EGR passage is reduced, and the responsiveness to the transition of the operating state of the engine can be improved.

  According to the exhaust gas recirculation device of the second aspect of the present invention, in the engine room, the exhaust gas purification device is installed to be inclined so that its outlet is close to the inlet of the EGR cooler, and the EGR cooler has its outlet Since it is installed to be inclined so as to be close to the intake passage, the EGR passage can be made as short as possible, and the responsiveness to the transition of the engine operating state can be improved. At this time, if the EGR valve is also installed in the engine room so that the outlet thereof is inclined so as to be close to the intake passage, the EGR passage can be made shorter, and the response to the transition of the engine operating state can be improved. This can be further improved (claim 3).

  Further, if the EGR valve is installed in the engine room side by side with the EGR cooler, the installation height of the EGR valve and the EGR cooler can be suppressed, and a large space can be secured above and below the EGR valve ( Claim 6). At this time, if it is applied to a four-wheel drive vehicle and the engine is in a horizontal layout, the vertical space around the transfer can be secured, which contributes to the improvement of transfer assembly. be able to. In other words, when the engine is placed horizontally in a four-wheel drive vehicle [particularly, when a supercharger is further provided (Claim 5)], a transfer may be installed below the EGR cooler or the EGR valve. Many. Under such circumstances, when the transfer is assembled to the vehicle body, the gear is assembled while meshing with the gear of the transmission, but this meshing operation requires a space in the vertical direction. Here, if the EGR valve is installed side by side with the EGR cooler, a large space in the vertical direction between the EGR valve and the EGR cooler and the transfer can be ensured. This can contribute to improvement (claim 8).

  Further, in the engine room, if the EGR valve is installed side by side with the EGR cooler, the passage in the EGR valve can be replaced (utilized) as a part of the EGR passage, and the EGR passage is made shorter. Therefore, the responsiveness to the transition of the operating state of the engine can be further improved (Claim 7).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
1 and 2 are views showing an exhaust gas recirculation device according to a first embodiment of the present invention. FIG. 1 is a schematic front view of the exhaust gas recirculation device installed in an engine room as viewed from the rear of a vehicle. FIG. 2 and FIG. 2 are schematic configuration diagrams for explaining how the exhaust gas recirculation device is provided for the intake passage and the exhaust passage of the engine. FIG. 3 is a diagram showing the exhaust gas recirculation device created in the process of creating the present invention, and is a schematic front view of the exhaust gas recirculation device installed in the engine room as seen from the rear of the vehicle. is there.

<Configuration>
As shown in FIG. 2, a common rail diesel engine (hereinafter simply referred to as an engine) 1 mounted in an engine room ER of a vehicle includes a cylinder head 2, a cylinder block 3, and a rocker cover 4. Yes. This vehicle is a four-wheel drive vehicle, and the engine 1 is installed in the engine room ER so that its crankshaft extends in the vehicle width direction, that is, horizontally. In addition, fuel that has been pumped to the common rail 8 by the supply pump 7 and becomes high pressure is injected into the combustion chamber of the engine 1.

  An intake port 11 and an exhaust port 21 are formed in the cylinder head 2 so as to face the combustion chamber 5. An intake manifold 12 is connected to the intake port 11, and an exhaust manifold 22 is connected to the exhaust port 21. The intake port 11 and the exhaust port 21 are opened and closed by an intake valve 13 or an exhaust valve 23, respectively.

An intake pipe 15 is connected to the upstream side of the intake manifold 12 via a surge tank 14. The intake passage 10 is formed from the intake manifold 12 and the intake pipe 15.
The intake pipe 15 includes an air cleaner (not shown), a first throttle valve 16, a compressor 6a (see FIG. 1) of a turbocharger (supercharger) 6, an intercooler 17 and a second throttle in order from the upstream side. A valve 18 is provided.

The air cleaner removes foreign matter contained in fresh air by filtering fresh air sucked from the outside.
Further, the first throttle valve 16 adjusts the amount of fresh air (fresh air amount) that has passed through the air cleaner, and by this adjustment, the EGR introduced into the intake pipe 15 via the first EGR passage 30 described later. The amount of gas (first EGR amount) is indirectly adjusted.

The turbocharger 6 increases the intake pressure, and includes a compressor 6a and a turbine 6b described later. The turbine 6b is rotationally driven by the flow of exhaust gas, and the compressor 6a connected coaxially with the turbine 6b is rotationally driven integrally with the turbine 6b to supercharge and increase the intake pressure.
The intercooler 17 cools the intake air compressed by the turbocharger 6.

The second throttle valve 18 adjusts the intake air amount (fresh air amount + first EGR amount) that has passed through the intercooler 17 and is introduced via a second EGR passage 40 (to be described later) by this adjustment. The amount of EGR gas (second EGR amount) is indirectly adjusted.
On the other hand, an exhaust pipe 25 is connected to the downstream side of the exhaust manifold 22, and the turbine 6 b (see FIG. 1) of the turbocharger 6, the exhaust purification device 26, and NO are connected to the exhaust pipe 25 in order from the upstream side. _{An X} trap catalyst 27 is provided. An exhaust passage 20 is formed from the exhaust manifold 22 and the exhaust pipe 25.

  The exhaust purification device 26 includes a diesel oxidation catalyst (hereinafter simply referred to as an oxidation catalyst) 26a, and a diesel particulate filter (hereinafter simply referred to as a DPF) 26b located downstream of the oxidation catalyst 26a. It is configured. Then, the exhaust purification device 26 causes reaction heat generated when the fuel is supplied to the oxidation catalyst 26a and undergoes an oxidation reaction to flow into the DPF 26b to raise the temperature of the DPF 26b, and the particulate matter (PM) collected by the DPF 26b. Is burned and removed.

NO _X trap catalyst 27 temporarily absorbs NO _X in the exhaust gas, then, intermittently reducing the occluded NO _X in a reducing atmosphere, so as to purify.
The intake pipe 15 between the first throttle valve 16 and the compressor 6 a and the exhaust pipe 25 between the exhaust purification device 26 and the NO _X trap catalyst 27 are a first EGR passage (low pressure EGR passage; EGR passage) 30. It is connected. The first EGR passage 30 recirculates a part of the exhaust gas from the exhaust pipe 25 to the intake pipe 15 as EGR gas. Then, in the first EGR passage 30, an EGR cooler 31 that cools the EGR gas and the amount of EGR gas (first EGR amount) that recirculates to the intake pipe 15 through the first EGR passage 30 in order from the upstream side. An EGR valve 32 for adjustment is provided.

Here, the exhaust gas recirculation device of the present invention is configured to include at least the exhaust gas purification device 26, the first EGR passage 30, the EGR cooler 31, and the EGR valve 32.
The intake pipe 15 between the second throttle valve 18 and the surge tank 14 and the exhaust pipe 25 on the upstream side of the turbine 6 b are connected by a second EGR passage (high pressure EGR passage) 40. Similarly to the first EGR passage 30, the second EGR passage 40 also recirculates a part of the exhaust gas as EGR gas to the intake pipe 15, but the pressure in the passage is higher than that of the first EGR passage 30. The second EGR passage 40 is provided with an EGR valve 42 that adjusts the amount of EGR gas (second EGR amount) that recirculates to the intake pipe 15 via the second EGR passage 40.

Here, as a major feature of the present embodiment, as shown in FIG. 1, the engine room is configured such that the exhaust purification device 26, the EGR cooler 31, and the EGR valve 32 have the entire length of the first EGR passage 30 as short as possible. It is installed at an angle in the ER. In FIG. 1, the vehicle width direction indicated by the arrow coincides with the horizontal direction.
That is, as shown in FIG. 3, the exhaust purification device 26, the EGR cooler 31, and the EGR valve 32 are normally installed in the engine room in an upright state with respect to a horizontal plane without being inclined (in FIG. 3). 3, the vehicle width direction indicated by the arrow coincides with the horizontal direction, and the devices and members corresponding to the exhaust purification device 26, the EGR cooler 31, the EGR valve 32, and the first EGR passage 30 of this embodiment are shown in FIG. (In order, they are shown with reference numerals 126, 131, 132, and 130).

However, in the present embodiment, as shown in FIG. 1, the exhaust purification device 26 is installed obliquely with respect to the horizontal plane so that the outlet thereof is as close as possible to the inlet of the EGR cooler 31.
Further, the EGR cooler 31 is also inclined and installed so that the outlet thereof is as close as possible to the intake pipe 15.

Further, the EGR valve 32 is also inclined and installed so that its outlet is as close as possible to the intake pipe 15. The EGR valve 32 is also installed side by side with the EGR cooler 31 in the horizontal direction.
That is, the exhaust purifying device 26, the EGR cooler 31, and the EGR valve 32 are not hindered by the functions of the devices 26, 31, 32 in consideration of the structure of the devices 26, 31, 32 and the layout to the engine room ER. And in the range in which these devices 26, 31, 32 are assembled without interfering with each other, they are inclined as described above.

<Action and effect>
Since the exhaust gas recirculation apparatus according to the first embodiment of the present invention is configured as described above, the following operations and effects are obtained.
In the engine room ER, the exhaust purification device 26 is installed so that its outlet is as close as possible to the inlet of the EGR cooler 31, so that the first EGR passage 30 between the exhaust purification device 26 and the EGR cooler 31 is provided. Can be shortened. In addition, since the EGR cooler 31 and the EGR valve 32 are inclined so that their outlets are as close as possible to the intake pipe 15, the first EGR extending from the EGR valve 32 to the intake pipe 15 through the EGR cooler 31. The passage 30 can be shortened. As a result, it is possible to improve the responsiveness of the exhaust gas recirculation device with respect to the transition of the engine operating state.

  In the engine room ER, the EGR cooler 31 and the EGR valve 32 are installed side by side in the horizontal direction, so that the installation height of the EGR cooler 31 and the EGR valve 32 can be suppressed, and a space is provided above and below it. Can be secured. As a result, as shown in FIG. 1, a wide vertical space around the transfer 51 can be secured, which can contribute to an improvement in the assembly of the transfer 51.

  That is, when the engine 1 is placed horizontally in a four-wheel drive vehicle and includes the turbocharger 6, the transfer 51 is often installed below the EGR cooler 31 and the EGR valve 32. Under such circumstances, when the transfer 51 is assembled to the vehicle body, the gear 51 is assembled while meshing with the gear of the transmission 52, but this meshing work requires a space in the vertical direction. Here, by arranging the EGR cooler 31 and the EGR valve 32 side by side in the horizontal direction, a wide space in the vertical direction between the EGR cooler 31 and the EGR valve 32 and the transfer 51 can be secured. It can contribute to the improvement of assembly.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a schematic front view of the exhaust gas recirculation device of the present embodiment installed in the engine room as viewed from the rear of the vehicle. The same devices and members as those in the first embodiment will be described with the same reference numerals as those in the first embodiment.

  In the present embodiment, the EGR cooler 31 ′ and the EGR valve 32 ′ are installed differently from the first embodiment, and the length of the first EGR passage 30 ′ is different. Since the rest is the same as that of the first embodiment, description thereof is omitted. That is, in the present embodiment, the EGR cooler 31 ′ and the EGR valve 32 ′ are installed side by side in the vertical direction in the engine room ER.

  According to the exhaust gas recirculation apparatus according to the second embodiment of the present invention, the passage in the EGR valve 32 'can be used as the first EGR passage 30', and the first EGR passage 30 'can be made shorter. And the responsiveness to the transition of the operating state of the engine 1 can be further improved.

[Others]
As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various deformation | transformation is possible in the range which does not deviate from the meaning of this invention.

  For example, in each of the above embodiments, the EGR coolers 31 and 31 ′ and the EGR valves 32 and 32 ′ are both inclined so that their outlets are close to the intake passage 10, but at least one of them is inclined. As long as it is installed. Thus, even if only one of them is inclined, the total length of the first EGR passages 30 and 30 'can be shortened compared to the case shown in FIG.

In each of the above embodiments, the first EGR passages 30 and 30 ′ extend from the exhaust passage 20 between the exhaust purification device 26 and the NO _X trap catalyst 27 toward the intake passage 10, but at least the exhaust purification device 26. As long as it extends from the exhaust passage 20 on the downstream side.
In each of the above embodiments, the EGR valves 32 and 32 'are provided on the downstream side of the EGR cooler 31 in the first EGR passages 30 and 30', but may be provided on the upstream side.

  In each of the above embodiments, the exhaust gas recirculation device is applied to a four-wheel drive vehicle, but may be applied to a two-wheel drive vehicle. Moreover, although applied to the diesel engine 1 in the said embodiment, you may apply to a gasoline engine.

It is a figure showing the exhaust gas recirculation device concerning a 1st embodiment of the present invention, and is the typical front view which looked at the exhaust gas recirculation device installed in the engine room from the back of vehicles. 1 is a diagram showing an exhaust gas recirculation device according to a first embodiment of the present invention, and is a schematic configuration for explaining how the exhaust gas recirculation device is provided for an intake passage and an exhaust passage of an engine FIG. It is a figure which shows the exhaust gas recirculation apparatus created in the process of creating this invention, Comprising: It is the typical front view which looked at the exhaust gas recirculation apparatus installed in the engine room from the back of a vehicle. It is a figure which shows the exhaust gas recirculation apparatus which concerns on 2nd Embodiment of this invention, Comprising: It is the typical front view which looked at the exhaust gas recirculation apparatus installed in the engine room from the back of a vehicle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Diesel engine 2 Cylinder head 3 Cylinder block 4 Rocker cover 5 Combustion chamber 6 Turbocharger (supercharger)
6a Compressor 6b Turbine 7 Supply pump 8 Common rail 10 Intake passage 11 Intake port 12 Intake manifold 13 Intake valve 14 Surge tank 15 Intake pipe 16 First throttle valve 17 Intercooler 18 Second throttle valve 20 Exhaust passage 21 Exhaust port 22 Exhaust Manifold 23 Exhaust valve 25 Exhaust pipe 26 Exhaust purification device 26a Diesel oxidation catalyst 26b Diesel particulate filter (DPF)
27 NO _X trap catalyst 30, 30 ′ First EGR passage (EGR passage)
31, 31 'EGR cooler 32, 32' EGR valve 40 Second EGR passage 42 EGR valve 51 Transfer 52 Transmission ER Engine room

Claims (8)

An exhaust purification device that is provided in an exhaust passage of an engine mounted on a vehicle and purifies exhaust gas of the engine;
An EGR passage that connects the exhaust passage downstream of the exhaust purification device and the intake passage of the engine, and returns a part of the exhaust gas purified by the exhaust purification device to the intake passage as EGR gas;
An EGR cooler provided in the EGR passage for cooling the EGR gas;
An exhaust gas recirculation device comprising an EGR valve provided in the EGR passage downstream of the EGR cooler and configured to adjust the amount of the EGR gas;
In the engine room of the vehicle where the engine is installed,
The exhaust purification device is installed with an inclination so that its outlet is close to the inlet of the EGR cooler,
The exhaust gas recirculation apparatus, wherein the EGR valve is inclined and installed such that an outlet thereof is close to the intake passage. An exhaust purification device that is provided in an exhaust passage of an engine mounted on a vehicle and purifies exhaust gas of the engine;
An EGR passage that connects the exhaust passage downstream of the exhaust purification device and the intake passage of the engine, and returns a part of the exhaust gas purified by the exhaust purification device to the intake passage as EGR gas;
An EGR cooler provided in the EGR passage for cooling the EGR gas;
An exhaust gas recirculation device comprising an EGR valve provided in the EGR passage and configured to adjust an amount of the EGR gas;
In the engine room of the vehicle where the engine is installed,
The exhaust purification device is installed with an inclination so that its outlet is close to the inlet of the EGR cooler,
The exhaust gas recirculation apparatus, wherein the EGR cooler is installed with an inclination so that an outlet thereof is close to the intake passage. The exhaust gas recirculation apparatus according to claim 2, wherein the EGR valve is installed in the engine room so as to be inclined so that an outlet thereof is close to the intake passage. The exhaust gas recirculation apparatus according to claim 2 or 3, wherein the EGR valve is provided in the EGR passage downstream of the EGR cooler. A turbocharger comprising a turbine provided in the exhaust passage and driven by a flow of exhaust gas; and a compressor provided in the intake passage and coaxially connected to the turbine. The exhaust gas recirculation device according to any one of claims 1 to 4. 6. The exhaust gas recirculation apparatus according to claim 1, wherein the EGR valve is installed side by side in a horizontal direction with the EGR cooler in the engine room. 6. The exhaust gas recirculation apparatus according to claim 1, wherein the EGR valve is installed in the engine room side by side with the EGR cooler in the vertical direction. The vehicle is a four-wheel drive vehicle,
The exhaust gas recirculation device according to any one of claims 1 to 7, wherein the engine is installed such that a crankshaft thereof extends in a vehicle width direction.

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