JPH06146908A - Engine with exhaust turbo supercharger - Google Patents

Abstract

PURPOSE:To prevent incomplete combustion, decrease compression ratio and enlarge the maximum output without varying structure member by communicating single auxiliary exhaust turbo supercharger whose volume is smaller than those of main exhaust turbo superchargers. CONSTITUTION:A gap between respective exhaust passages 5, 6 and respective main exhaust turbo superchargers 7, 8 and a gap between one exhaust passage 5 and the other exhaust passage 6 are opened/closed in response to engine speed. A single auxiliary exhaust turbo supercharger 29 whose volume is smaller than those of the main exhaust turbo superchargers 7, 8 is communicated with both exhaust passages 5, 6 and the gap between the auxiliary exhaust turbo supercharger 29 and both exhaust passages 5, 6 is opened/closed according to the engine speed. Therefore, when a load is small due to super-low speed rotation like the idling time turbine rotational speed of the auxiliary exhaust turbo supercharger 29 can be increased even if an exhaust gas quantity is small by compressing intake air by the auxiliary exhaust turbo supercharger 29, and the intake pressure can be remarkably increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine in which a plurality of exhaust turbochargers are selectively used according to the number of revolutions.

[0002]

2. Description of the Related Art An engine 100 with an exhaust turbocharger shown in FIGS. 11 to 13 has a plurality of cylinders 101, two twin scroll type exhaust turbochargers 102 and 103 having the same capacity, and a communication passage. Two exhaust passages 105 and 106 communicating with each other via 104 are provided. Each cylinder 1
01 is divided into a group connected to one exhaust passage 105 and a group connected to the other exhaust passage 106.

One scroll 102a of one exhaust turbocharger 102 and one group of cylinders 101 are always in communication with each other, and the other scroll 102b of one exhaust turbocharger 102 and the cylinder 101 of one group. The open / close valve 107 opens and closes the communication passage 104 and the cylinder 101 of one group. Further, an opening / closing valve 108 opens and closes between one scroll 103a of the other exhaust turbocharger 103 and the cylinder 101 of the other group, and between the communication passage 104 and the cylinder 101 of the other group, and the other exhaust gas is exhausted. An on-off valve 109 opens and closes between the other scroll 103b of the turbocharger 103 and the cylinder 101 of the other group.

Incidentally, each exhaust turbocharger 102, 103
The intake air compressed by is supplied to each cylinder 101 from the intake pipes 110 and 111 through the intercooler 112, and the exhaust gas that drives the exhaust turbochargers 102 and 103 is exhausted from the exhaust pipe 113. And each on-off valve 10
7, 108 and 109 are opened and closed according to the engine speed.

That is, at low speed rotation, as shown in FIG. 11, one group of cylinders 101 communicates with one scroll 102a of one exhaust turbocharger 102, and the other group of cylinders 101 has a communication passage 104. Via one side of the exhaust turbocharger 102 to communicate with the other scroll 102b. As a result, one exhaust turbocharger 102
Intake is compressed by driving only.

At the middle speed rotation, as shown in FIG. 12, the cylinders 101 of one group are connected to one exhaust turbocharger 10 of the other group.
The two cylinders 101 of the other group communicate with one scroll 103a of the other exhaust turbocharger 103. As a result, intake air is compressed by driving each of the exhaust turbochargers 102 and 103 with the exhaust gas introduced into one of the scrolls.

At the time of high speed rotation, as shown in FIG. 13, the cylinders 101 of one group are connected to the exhaust turbocharger 10 of one group.
2 is connected to both scrolls 102a and 102b, and the cylinder 101 of the other group is connected to the other exhaust turbocharger 103.
The two scrolls 103a and 103b communicate with each other. As a result, intake air is compressed by driving both exhaust turbochargers 102 and 103.

The above-described structure is intended to increase the intake pressure over a wide range of engine speeds by changing the capacity of the exhaust turbocharger according to the engine speed.

[0009]

However, in the above-mentioned conventional configuration, when the load is very low and the load is small, such as during idling, one exhaust turbocharger 1 as shown in FIG.
Even if the intake air is compressed only by 02, the turbine speed cannot be increased because the exhaust gas amount is small relative to the capacity of the exhaust turbocharger 102, and therefore the intake pressure can be increased sufficiently. could not. Then, there is a problem that the bluish-white exhaust gas containing fine fuel particles is discharged due to poor combustion, and the maximum output cannot be increased unless the strength of the structural member is increased because the compression ratio cannot be lowered.

An object of the present invention is to provide an engine with an exhaust turbocharger which can solve the above-mentioned problems of the prior art.

[0011]

The first aspect of the present invention is to provide a plurality of cylinders and two main exhaust turbochargers having the same capacity.
Each cylinder is divided into a group connected to one exhaust passage and a group connected to the other exhaust passage, and each exhaust passage and each main exhaust turbocharger. Between the exhaust passage and one exhaust passage and the other exhaust passage according to the engine speed.In an engine with an exhaust turbocharger, a single auxiliary exhaust with a smaller capacity than the main exhaust turbocharger. The turbocharger is connected to both exhaust passages, and the auxiliary exhaust turbocharger and both exhaust passages are opened / closed according to the engine speed.

According to the second aspect of the present invention, a plurality of cylinders and two main exhaust turbochargers having the same capacity are connected to each other.
Each cylinder is divided into a group connected to one exhaust passage and a group connected to the other exhaust passage, and each cylinder is connected between each exhaust passage and each main exhaust turbocharger and In an engine with an exhaust turbocharger that opens and closes between one exhaust passage and the other exhaust passage according to the engine speed, each exhaust passage has an auxiliary exhaust turbocharger with a smaller capacity than the main exhaust turbocharger. When the auxiliary exhaust turbocharger and each exhaust passage are opened, the auxiliary exhaust turbocharger and each exhaust passage are opened and closed according to the engine speed. The exhaust passage and the other exhaust passage are closed.

[0013]

According to the first and second aspects of the present invention, when the load is extremely low and the load is small, such as when idling, the intake air is supplied by the auxiliary exhaust turbocharger having a smaller capacity than the main exhaust turbocharger. By compressing, even if the amount of exhaust gas is small, the turbine speed of the auxiliary exhaust turbocharger can be increased, and the intake pressure can be increased sufficiently.

According to the structure of the second invention, the same operation as that of the first invention can be achieved, and one of the exhaust passages is opened when the space between each auxiliary exhaust turbocharger and each exhaust passage is opened. And the other exhaust passage, the exhaust from one cylinder and the exhaust from the other cylinder do not interfere between the one exhaust passage and the other exhaust passage. It is possible to prevent combustion failure due to backflow of exhaust gas and contamination of intercooler and the like.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

The diesel engine 1 with an exhaust turbocharger shown in FIG. 1 has six cylinders 2 and two twin scroll type main exhaust turbochargers 7 and 8 having the same capacity.
And two exhaust passages 5 and 6 communicating with each other through the communication passage 18. Each cylinder 2 is divided into a group connected to one exhaust passage 5 and a group connected to the other exhaust passage 6.

One of the exhaust passages 5 is connected to one of the groups 3
An exhaust manifold 3 connected to one cylinder 2, a first duct 21 connecting the exhaust manifold 3 and one scroll 7a of one main exhaust turbocharger 7, and the exhaust manifold 3 and one main exhaust The second duct 22 is connected to the other scroll 7b of the turbocharger 7. The first duct 21 and the exhaust manifold 3
Between the second duct 22 and the exhaust manifold 3 and the communication passage 18
The second on-off valve 26 opens and closes between the exhaust manifold 3 and the exhaust manifold 3.

The other exhaust passage 6 is provided in the other group 3
An exhaust manifold 4 connected to one cylinder 2, a third duct 23 connecting the exhaust manifold 4 and one scroll 8a of the other main exhaust turbocharger 8, and the exhaust manifold 4 and the other main exhaust The fourth duct 24 is connected to the other scroll 8b of the turbocharger 8. In the other exhaust passage 6, the auxiliary exhaust passage 2
A single scroll type auxiliary exhaust turbocharger 29 is connected via 8. This auxiliary exhaust turbocharger 2
The capacity of 9 is about 1/2 of the capacity of the main exhaust turbochargers 7 and 8.
Is. A third opening / closing valve 27 opens and closes between the third duct 23 and the exhaust manifold 4, and between the communication passage 18 and the exhaust manifold 4, and between the fourth duct 24 and the exhaust manifold 4 and the auxiliary exhaust passage 28. The fourth on-off valve 31 opens and closes between the exhaust manifold 4 and the exhaust manifold 4.

Each of the main exhaust turbochargers 7 and 8 compresses the intake air sucked through the filters 12 and 13, and introduces the intake air into the intercooler 14 through the air supply pipes 9 and 10 to cool the intake air. The intake manifold is supplied to the intake manifold 15
Is supplied to each cylinder 2 via. Further, the exhaust gas that drives the main exhaust turbochargers 7 and 8 is discharged from the exhaust gas collecting passage 11. The air supply pipes 9 and 10 are provided with check valves 16 and 17, respectively.

The auxiliary exhaust turbo supercharger 29 compresses the intake air taken in through the filter 32, introduces the intake air from the auxiliary air supply pipe 33 into the air supply manifold 15 without passing through the intercooler 14, and supplies the intake air. Supply from the manifold 15 to each cylinder 2. Further, the exhaust gas that drives the auxiliary exhaust turbocharger 29 is discharged from the auxiliary exhaust pipe 30 through the exhaust collecting passage 11. The auxiliary air supply pipe 33
A check valve 34 is provided in the.

Each on-off valve 25, 26, 27, 31 is driven by an actuator 36, 37, 38, 39, and each actuator 36, 37, 38, 39 responds to the number of revolutions of the engine 1 detected by a sensor 35. Control device 40
Controlled by.

The control device 40 controls the actuators 36, 37, 38, 39 so that the exhaust passages 5, 6 are connected between the exhaust passages 5, 6 and the main exhaust turbochargers 7, 8. And the other exhaust passage 6, and between the auxiliary exhaust turbocharger 29 and the exhaust passages 5 and 6 are opened and closed according to the engine speed.

That is, during an extremely low speed rotation such as idling, as shown in FIG. 1, all the cylinders 2 communicate only with the scrolls of the auxiliary exhaust turbocharger 29, and the other scrolls are closed. As a result, the intake air is compressed by driving only the auxiliary exhaust turbocharger 29.

At the time of low speed rotation, as shown in FIG. 2, the cylinder 2 of one group communicates with the scroll 8a of the other exhaust turbocharger 8 through the communication passage 18, and the cylinder 2 of the other group. Communicates with the other scroll 8b of the other exhaust turbocharger 8 and the other scrolls are closed.
As a result, the intake air is compressed by driving only the other exhaust turbocharger 8.

At the medium speed rotation, as shown in FIG. 3, the cylinder 2 of one group communicates with the other scroll 7b of the one exhaust turbocharger 7, and the cylinder 2 of the other group exhausts the other. It communicates with the other scroll 8b of the turbocharger 8, and the other scrolls are closed. As a result, intake air is compressed by driving the exhaust turbochargers 7 and 8 with the exhaust gas introduced into one scroll.

At the time of high speed rotation, as shown in FIG. 4, the cylinder 2 of one group communicates with both scrolls 7a and 7b of the exhaust turbocharger 7, and the cylinder 2 of the other group exhausts the other. The scrolls 8a and 8b of the turbocharger 8 communicate with each other, and the other scrolls are closed. In this way, the intake air is compressed by driving both exhaust turbochargers 7 and 8. It should be noted that the state shown in FIG. 4 is also set at the time of starting to prevent starting failure due to an increase in engine back pressure.

According to the above-mentioned embodiment, when the load is low and the load is small, such as during idling, the intake air is compressed by the auxiliary exhaust turbocharger 29 having a smaller capacity than the main exhaust turbochargers 7, 8. Thus, even if the amount of exhaust gas is small, the turbine speed of the auxiliary exhaust turbocharger can be increased, the intake pressure can be increased sufficiently, and the intake air can be supplied to each cylinder 2 without passing through the intercooler 14. Since it is supplied, the intake air temperature can be raised. As a result, it is possible to prevent poor combustion and increase the maximum output without lowering the compression ratio and changing the structural members.

FIG. 5 to FIG. 8 show the second embodiment, which is the first embodiment described above.
The same parts as those in the embodiment are designated by the same reference numerals, and different points will be described.

First, a single scroll type second auxiliary exhaust turbocharger 52 is connected to one exhaust passage 5 via a second auxiliary exhaust passage 51. The capacity of the second auxiliary exhaust turbocharger 52 is the main exhaust turbocharger 7, 8
Is about 1/4 of the capacity. A first opening / closing valve 25 and a fifth opening / closing valve 54 are opened and closed between the first duct 21 and the exhaust manifold 3, and a first opening / closing valve 25 and a second opening / closing are provided between the second duct 22 and the exhaust manifold 3. Valve 26
The second opening / closing valve 26 opens / closes between the communication passage 18 and the exhaust manifold 3, and the fifth opening / closing valve 54 opens / closes between the second auxiliary exhaust passage 51 and the exhaust manifold 4. The fifth on-off valve 54 is driven by the actuator 41, and the actuator is controlled by the control device 40 together with other on-off valves according to the rotation speed of the engine 1 detected by the sensor 35.

Further, the second auxiliary exhaust turbocharger 52
Compresses the intake air sucked through the filter 55, introduces the intake air from the auxiliary air supply pipe 56 into the air supply manifold 15 without passing through the intercooler 14, and supplies the intake air to each cylinder 2 from the air supply manifold 15. Also, the second
The exhaust that has driven the auxiliary exhaust turbocharger 52 is discharged from the second auxiliary exhaust pipe 53 through the exhaust collecting passage 11. A check valve 57 is provided on the second auxiliary air supply pipe 56.

By controlling the actuators 36, 37, 38, 39, 41 by the controller 40, between the exhaust passages 5, 6 and the main exhaust turbochargers 7, 8,
The exhaust passage 5 on one side and the exhaust passage 6 on the other side, and the auxiliary exhaust turbochargers 29, 52 and the exhaust passages 5, 6 are opened and closed according to the engine speed.

That is, at the time of ultra-low speed rotation such as idling, as shown in FIG.
Communicates with the scroll of the second auxiliary exhaust turbocharger 52, and the cylinder 2 of the other group has the auxiliary exhaust turbocharger 2
9 scrolls, other scrolls are closed,
Further, the one exhaust passage 5 and the other exhaust passage 6 are closed so as not to communicate with each other. Accordingly, the auxiliary exhaust turbocharger 29 and the second auxiliary exhaust turbocharger 52
To compress the intake air.

At low speed rotation, as shown in FIG. 6, the cylinder 2 of one group communicates with the scroll 8a of the other exhaust turbocharger 8 through the communication passage 18, and the cylinder 2 of the other group. Communicates with the other scroll 8b of the other exhaust turbocharger 8 and the other scrolls are closed.
As a result, the intake air is compressed by driving only the other exhaust turbocharger 8.

At the medium speed rotation, as shown in FIG. 7, the cylinder 2 of one group communicates with the other scroll 7b of the one exhaust turbocharger 7, and the cylinder 2 of the other group exhausts the other. It communicates with the other scroll 8b of the turbocharger 8, and the other scrolls are closed. As a result, intake air is compressed by driving the exhaust turbochargers 7 and 8 with the exhaust gas introduced into one scroll.

At the time of high speed rotation and starting, as shown in FIG. 8, the cylinder 2 of one group communicates with both scrolls 7a and 7b of the exhaust turbocharger 7, and the cylinder 2 of the other group has The other scroll is connected to both scrolls 8a and 8b of the exhaust turbocharger 8 and the other scrolls are closed. In this way, the intake air is compressed by driving both exhaust turbochargers 7 and 8. Others are the same as those in the first embodiment.

According to the second embodiment described above, the same operation as that of the first embodiment can be achieved, and the exhaust gas from the cylinder 2 of one group is disposed between the one exhaust passage 5 and the other exhaust passage 6. Since there is no interference with the exhaust gas from the cylinders 2 of the other group, it is possible to prevent the combustion failure and the contamination of the intercooler and the like due to the reverse flow of the exhaust gas.

FIG. 9 compares the blue-white smoke concentration containing fine fuel particles due to poor combustion between the conventional example and each example. According to each example, the blue-white smoke concentration is lower than that of the conventional example. Can be confirmed. Further, FIG. 10 is a comparison of the relationship between the engine speed and the load between the conventional example and each example. According to each example, the compression ratio is made lower than that of the conventional example and the structural member is changed. You can see that you can increase the maximum output without.

[0038]

According to the present invention, when the load is low and the load is small, such as when idling, the intake pressure can be increased by increasing the turbine speed of the auxiliary exhaust turbocharger even if the exhaust gas amount is small. It can be made sufficiently high, incomplete combustion can be prevented, and the compression ratio can be lowered to increase the maximum output without changing structural members.

Further, according to the second aspect of the present invention, since the exhaust interference does not occur in the exhaust passage, it is possible to prevent the combustion failure and the contamination of the intercooler and the like due to the reverse flow of the exhaust.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an engine configuration according to a first embodiment of the present invention at an ultra-low speed.

FIG. 2 is a structural explanatory view of an engine at a low speed according to the first embodiment of the present invention.

FIG. 3 is a structural explanatory view of the engine at a medium speed according to the first embodiment of the present invention.

FIG. 4 is a structural explanatory view of an engine at a high speed according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram of an engine configuration according to a second embodiment of the present invention at an ultra-low speed.

FIG. 6 is an explanatory diagram of a configuration of an engine at a low speed according to a second embodiment of the present invention.

FIG. 7 is a structural explanatory view of an engine at a medium speed according to a second embodiment of the present invention.

FIG. 8 is a structural explanatory view of an engine at a high speed according to a second embodiment of the present invention.

FIG. 9 is a diagram showing blue-white smoke density in a conventional example and each example.

FIG. 10 is a diagram showing a relationship between engine speed and load.

FIG. 11 is an explanatory diagram of a configuration of an engine at a low speed of a conventional example.

FIG. 12 is a structural explanatory view of an engine at a medium speed of a conventional example.

FIG. 13 is an explanatory diagram of a configuration of an engine at a high speed of a conventional example.

[Explanation of symbols]

 1 engine 2 cylinders 5 and 6 exhaust passage 7 and 8 main exhaust turbocharger 18 communication passage 25, 26, 27, 31, 54 on-off valve 29 auxiliary exhaust turbocharger 52 second auxiliary exhaust turbocharger

Claims (2)

[Claims] 1. A plurality of cylinders, two main exhaust turbochargers having the same capacity, and two exhaust passages communicating with each other are provided, and each cylinder includes a group connected to one exhaust passage and a group connected to the other. Exhaust that is divided into groups connected to the exhaust passage, and that is opened and closed between each exhaust passage and each main exhaust turbocharger and between one exhaust passage and the other exhaust passage according to the engine speed. In an engine with a turbocharger, a single auxiliary exhaust turbocharger with a smaller capacity than the main exhaust turbocharger is connected to both exhaust passages, and between the auxiliary exhaust turbosupercharger and both exhaust passages. Is an engine with an exhaust turbocharger that opens and closes according to the engine speed. 2. A plurality of cylinders, two main exhaust turbochargers having the same capacity, and two exhaust passages communicating with each other are provided, and each cylinder includes a group connected to one exhaust passage and a group connected to the other exhaust passage. Exhaust that is divided into groups connected to the exhaust passage, and that is opened and closed between each exhaust passage and each main exhaust turbocharger and between one exhaust passage and the other exhaust passage according to the engine speed. In an engine with a turbocharger, an auxiliary exhaust turbocharger having a smaller capacity than the main exhaust turbocharger is connected to each exhaust passage, and the engine is connected between each auxiliary exhaust turbocharger and each exhaust passage. An engine with an exhaust turbocharger that opens and closes according to the number of revolutions and closes between one exhaust passage and the other exhaust passage when opening between each auxiliary exhaust turbocharger and each exhaust passage.