JPS61283725A - Internal-combustion engine provided with turbocharger - Google Patents

Abstract

PURPOSE:To aim at high supercharging pressure over an extent ranging from a low speed range to a high speed one in an internal-combustion engine so extensively, by using plural turbochargers, and letting them perform separate or parallel driving at need. CONSTITUTION:At a low speed range of an engine, a first on-off valve V1 and a fourth on-off valve V4 comes into a state of being closed, while both second and third on-off valves V2 and V3 come into a state of being opened, and a first turbocharger 7 comes to a suspension state, thus a second turbocharger 8 alone is used. At the time of a medium speed range, these first and fourth on-off valves V1 and V4 come to an open state but second and fourth on-off valves V2 and V4 to a close state, while both first and second turbochargers 7 and 8 are separately used each. At a high speed range, each of these on-off valves V1, V2, V3 and V4 comes to a state of being opened, whereby a first exhaust passage 3 and a second exhaust passage 5 both are interconnected to an exhaust interconnecting passage 9 so that both turbochargers 7 and 8 are used in parallel.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an internal combustion engine equipped with a turbocharger.

(Prior Art) Generally, a turbocharger installed in an internal combustion engine uses the energy of exhaust gas to rotate a turbine, drives a compressor coaxial with the turbine, and supplies compressed air to the engine. The purpose is to improve charging efficiency, engine output, torque, etc. by supercharging). In an internal combustion engine equipped with such a turbocharger, i
) Sufficient boost pressure can be obtained in the medium to high speed range of an internal combustion engine, but it is difficult to obtain sufficient boost pressure in the low speed range, and the torque at low speeds tends to be insufficient. In addition, i) When accelerating an internal combustion engine from low speed to high speed, the turbocharger turbine starts operating at a low rotation speed, so acceleration response tends to be poor due to the inertia of the turbine. Ta.

Conventionally, as a countermeasure against this, a variable capacity turbocharger is used for the above, and the above-mentioned 11)
In this case, a combination of a variable displacement turbocharger driven by the output shaft of an internal combustion engine and a normal turbocharger was used.

(Problems to be Solved by the Invention) However, in the past, torque in the low speed range was improved by using a variable displacement turbocharger or a combination of a variable displacement turbocharger and a normal turbocharger. Since the structure was designed to improve acceleration response, there were problems in that the structure was not only complicated but also difficult to miniaturize.

Therefore, the present invention provides a turbocharger that can obtain high supercharging pressure over a wide rotational speed range from low to high rotational speeds of an internal combustion engine by using a plurality of turbochargers and operating them in parallel as necessary. The purpose of this invention is to provide an internal combustion engine equipped with the following.

(Means for Solving Problems and Their Effects) An internal combustion engine equipped with a turbocharger of the present invention includes a plurality of mutually independent combinations of intake passages and exhaust passages, and each set is provided with a turbocharger. has been done.

Further, the exhaust passages in which the turbines of each turbocharger are disposed are communicated with each other on the upstream side of each turbine by an exhaust side communication passage, and an on-off valve is disposed in the exhaust side communication passage. On the other hand, each intake passage in which a compressor and a bush of each turbocharger are disposed are communicated with each other on the downstream side of each compressor by an intake side communication passage. moreover,
Among the exhaust passages, the downstream side of the exhaust-side communication passage of some sets of exhaust passages and the upstream side of the intake-side communication passage of the intake passages that are paired with the above-mentioned part of the exhaust passages are provided with opening/closing passages that open and close in conjunction with each other. A valve is provided in each case. Therefore, by appropriately controlling the opening/closing operation of the on-off valve according to the operating state of the engine, it is possible to increase the supercharging pressure of the intake air in the low speed rotation range.

(Example) An example of the present invention will be described below based on the accompanying drawings.

First, a first embodiment will be described based on FIGS. 1 and 2. In this embodiment, a case where the present invention is applied to two cylinders of an internal combustion engine will be described as an example.

As shown in FIG. 1, the internal combustion engine of this embodiment includes a first cylinder (1) and a second cylinder (2).
A set of first exhaust passages (3) and a first intake passage (4) are connected to the cylinder, and a second exhaust passage (5) of a set of - is connected to the second cylinder (2).
) and the second intake passage (6) are connected. Also, the first
A turbine (7a) of a first turbocharger (7) is disposed in the exhaust passage (3), and a compressor (7c) fixed to its rotor shaft (7b) is installed in the first turbocharger (7).
On the other hand, the turbine (8) of the second turbocharger (8) is disposed in the second exhaust passage (5).
8a) and its rotor shirt) (
A compressor (8C) fixed to the air compressor (8b) is arranged in the second intake passage (6). In this way, the combinations of exhaust passages and intake passages are provided independently, and a turbocharger is provided for each of these combinations.

Furthermore, the first exhaust passage (3) and the second exhaust passage (5) are on the upstream side of the turbine (7a) of the first turbocharger (7) and the turbine (8a) of the second turbocharger (8), and are on the exhaust side. The first exhaust passage (3), which is one of the exhaust passages, is connected to the exhaust side communication passage (9) on the downstream side of the communication passage (9). A first on-off valve (V
θ is arranged. Furthermore, the above-mentioned exhaust side communication passage (8)
A second on-off valve (v2) and a third on-off valve (v3) for opening and closing the communication port of the exhaust side communication path (8) are provided on both communication end sides of the exhaust side communication path (8).
) are provided.

On the other hand, the compressor (7C) of the first turbocharger (7) is installed in both the first intake passage (0) and the second intake passage (6).
) and the compressor of the second turbocharger (8) (
8c) and the first cylinder (1) and the second cylinder (
A chamber (intake side communication passage) (10) is interposed in the vicinity of 2), and this chamber (lO) allows the first intake passage (4) and the second intake passage (5) to connect to each compressor (7c).
), (8c), and is connected to the first intake passage (4) which forms a pair with the first exhaust passage (3) in which the first on-off valve (V+) is disposed. (4) A fourth on-off valve (v4) that opens and closes is provided. Open/close valve (V
+), (V2), (V3), (V4), the first on-off valve (V+), the fourth on-off valve (v4), the second
The on-off valve (V2) and the third on-off valve (v3) are each driven in conjunction with each other by actuators (not shown), and each actuator is controlled by a controller that outputs a drive signal based on the engine speed (Me). The structure is as follows. In addition, (11) and (12) in the figure
) is the throttle valve.

In such an internal combustion engine, each on-off valve (V+) to (
V4) is driven by the controller based on the drive mode shown in Table 1, for example.

That is, in range A where the engine speed (Me) is low, the first
While the on-off valve (Vl) and the fourth on-off valve (v4) are in the closed state, the second on-off valve (v2) and the third on-off valve (v3) are controlled in the open state, so the first turbocharger (7) is at rest and only the second turbocharger (8) is used. Therefore, the exhaust gas from both cylinders (1) and (2) is supplied to the turbine (8a) of the second turbocharger (8), so the second turbocharger (8) is operated with high efficiency, and the chamber (10) The supercharging pressure of the intake air supplied to the engine is increased. Therefore, low speed rotation range A
As shown by curve al in Fig. 2, the supercharging pressure P2 can be increased to approximately the same level as that at the medium/high speed port, transition areas B and C, and thereby the engine output (ps) can be increased to the level shown by curve al in Fig. 2. curve a
As shown in 2, it becomes possible to increase the amount. As a result, it is possible to solve the problem of torque shortage during low-speed rotation, and to improve acceleration response performance from low-speed rotation.

In medium speed rotation range B where the rotation speed further increases, the first and fourth on-off valves (vl) and (v4) are in the open state, and the second and third on-off valves (v2) and (v3) are in the closed state. Because of this control, the first turbocharger (7) and the second turbocharger (8) are used independently. The boost pressure and engine output in this case are curve bl in Fig. 2.
, b2, the supercharging flow rate and supercharging pressure can be maintained sufficiently.

In addition, in the high speed rotation range C, the first and second exhaust passages (3
), (5) increases, exhaust pressure increases, and engine filling efficiency deteriorates.
2) , (V3) , (V4) Fully open 7Q
2) The first exhaust passage (3) and the second exhaust passage (5)
Both turbochargers (7) and (8) will be used in a state where they are in communication with each other. The supercharging pressure and engine output in this case are as shown by curves CI and C2 in FIG. 2, and the supercharging pressure can be maintained sufficiently. In addition, the exhaust side communication path (
9) are in communication, the capacity of the entire exhaust passage increases, and as a result, the pulsation of the exhaust pressure is automatically controlled, making it possible to lower the exhaust pressure and also increase the capacity of the entire exhaust passage. , (8a) can be reduced, and the drive efficiency of the turbocharger can be improved.

In this way, in this embodiment, a high supercharging pressure can be obtained over a wide range of engine speeds.

Next, a second embodiment will be described. Note that the same parts as in the first embodiment are given the same reference numerals and redundant explanations will be omitted.

This embodiment is applied to a single-cylinder, 4-valve type internal combustion engine, and as shown in Fig. 3, one cylinder (20)
It is provided with two combinations of intake passages and exhaust passages.

That is, a first exhaust passage (3) and a first intake passage C4), and a second exhaust passage (5) and a second intake passage (6) are connected to the cylinder (20), which is different from the first embodiment. Similarly, the first
The exhaust passage (3) and the second exhaust passage (5) are connected to each other by the exhaust side communication passage (9), and the first intake passage (4) and the second intake passage (6) are connected to each other by the exhaust side communication passage (9).
) are in communication with each other through a chamber (10), and the first turbocharger (7) and the second turbocharger (8)
are arranged for each group. In addition, the first exhaust passage (
3), a first on-off valve (v
l) has a second on-off valve (v2) in the exhaust side communication passage (9).
) is the first intake passage (4) which is paired with the first exhaust passage (3).
), a third on-off valve (v3) is disposed at each outlet opening. Furthermore, the first exhaust valve (21a) of the exhaust boat connected to the first exhaust passage (3) and the first intake passage (
4) of the intake boat connected to the first intake valve (21b
) are connected to the valve stop mechanism (23), and the first intake and exhaust valves (21b) and (21a) are connected to the valve stop mechanism (23) during low speed rotation.
The structure is such that the drive is stopped. In addition, in the figure (22
(a) shows the second exhaust valve, and (22b) shows the second intake valve.

In such an internal combustion engine, each turbocharger is driven based on the drive mode shown in Table 2, for example.

Table 2 shows that in the low speed rotation range, the first and third on-off valves (V
+) and '(V3) are both controlled to the closed state, and the first
Exhaust valve (21a) and first intake valve (21b)
Both are controlled to be in a rest state by a valve rest mechanism (23). In this case, the second on-off valve (v2) may be in either the open or closed state. Therefore, in the low-speed rotation range, the exhaust gas flows through the turbine (8) of the other second turbocharger (8).
This means that the supercharging pressure by the second turbocharger (8) can be increased. Further, even when the effect of the second turbocharger (8) is not so great as during extremely low speed rotation, the charging efficiency is increased by the pulsation of intake and exhaust air.

In the medium speed rotation range, the first and third on-off valves (V+), (V
3) is in the open state, the second on-off valve (v2) is controlled to be in the closed state, and the valve is not stopped and the first exhaust valve (21a)
And the second intake valve (21b) is controlled to be in the driven state. Therefore, the first turbocharger (7) and the second turbocharger (8) are driven independently.

In addition, in the high-speed rotation range, the first, second, and third on-off valves (V+
), (V2), and (V3) are all controlled to be open and the valves are not stopped; therefore,
In the medium to high speed rotation range, high torque can be obtained over a wide engine rotation range as in the first embodiment.

In addition, the above-mentioned first to third on-off valves (V+), (V2),
(V3) (1) The switching operation and the valve stopping operation do not necessarily have to be performed at the same timing.

Next, a third embodiment will be explained based on FIG. 4.

This embodiment has two cylinders (1) and (
Of 2), this is applied to an engine equipped with a valve deactivation mechanism (3o) that deactivates the exhaust and intake valves of one cylinder (1) as necessary and operates each cylinder in the highest efficiency range. . The driving mode in this case is, for example, according to Table 3.

Table 3 shows that in the low speed rotation range, the first and fourth on-off valves (v
Only cylinders l) and (v4) are driven to the closed state, and the first cylinder (1
) is controlled to be in a rest state by a valve rest mechanism (30). In this case, the second and third on-off valves (v2
) and (v3) may be in either open or closed state. Therefore, only the second turbocharger (8) is in the driving state in the low speed rotation range, and the supercharging pressure in the low speed rotation range can be increased.

Next, a fourth embodiment will be described based on FIG. 5.

In addition to the first embodiment, this embodiment includes a first exhaust passage (4) between the exhaust side communication passage (9) and the turbine (7a) of the first turbocharger (7), and a second turbocharger (8).
and the second exhaust passage (5) on the downstream side of the turbine (8a),
A fifth valve that communicates with the second exhaust side communication passage (4o) and operates in conjunction with each communication port of the second exhaust side communication passage (40).
It is equipped with an on-off valve (v5). The driving mode in this case is, for example, according to Table 4.

In Table 4, the fifth on-off valve (v5) is controlled to be open only in the low speed rotation range, and is controlled to be closed in the middle and high speed rotation ranges. Therefore, during low-speed rotation, the first turbocharger (7) is in a rest state as in the first embodiment, only the second turbocharger (8) is driven to increase the supercharging pressure, and the second turbocharger (8) is in a rest state.
) is also supplied to the turbine (7a) of the first turbocharger (7) which is at rest through the second exhaust side communication passage (40). The turbine (7) of the first turbocharger (7)
a) is rotated in advance. Therefore, when the engine speed suddenly increases from a low speed, the first turbocharger (7) that is at rest can be quickly driven, and response performance can be improved. Moreover, instead of providing the second exhaust side communication passage (40), the first on-off valve (vl
It is also possible to obtain the same effect by appropriately controlling the opening degree of ).

In the first to fourth embodiments described above, a case has been described in which each on-off valve is controlled based on the engine speed. It may also be controlled. In addition, as the drive mode of each on-off valve in each embodiment, the first to fourth
The number of cylinders is not limited to those shown in the table, and may be set as appropriate depending on the turbine and exhaust passage.Furthermore, the number of cylinders is not limited to single or double cylinders, and multiple combinations of intake passages and exhaust passages may be configured. It can be applied if it is done.

Furthermore, the first turbocharger of each of the above embodiments and @2
Although turbochargers with the same capacity are used, the configuration is not limited to this, and the configuration can be made by combining turbochargers with different capacities, and the number of turbochargers is not limited to two, but can also be configured using multiple turbochargers. It is also possible to do so.

(Effects of the Invention) As is clear from the above description, according to the present invention, high supercharging pressure can be obtained over a wide range of engine speeds. especially,
Since the intake air supercharging pressure can be increased in the low speed rotation range, the engine output can be increased in the low speed rotation range, thereby resolving the lack of torque and improving acceleration response performance from low speed rotation. can. Also, during
It is possible to maintain sufficient supercharging pressure in the high-speed rotation range, and it is possible to reduce exhaust pulsation particularly in the high-speed rotation range, thereby improving the driving efficiency of the turbocharger.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 relate to a first embodiment of the present invention.
Figure 2 is a schematic diagram showing the intake and exhaust passages of an internal combustion engine, Figure 2 is a diagram showing the relationship between engine speed, boost pressure, and engine output, Figure 3 is a diagram showing the relationship between engine speed, boost pressure, and engine output.
The figure is a schematic diagram of the intake/exhaust passage according to the second embodiment, FIG. 4 is a schematic diagram of the intake/exhaust passage according to the third embodiment, and FIG.
FIG. 3 is a schematic diagram of an intake/exhaust passage according to an embodiment. In addition, (3>, (5) in the drawings are the first and second exhaust passages,
(4) and (6) are first and second intake passages; (7); (7a), (7c) are the first turbocharger, turbine and compressor, (8), (8a), (8q) are the second turbocharger, turbine and compressor, (
9). (40) is the exhaust side communication path, (10) is the intake side communication path (chamber), (V+), (V2), (V3)
, (V4) , (VsHt on-off valve. Figure 1 Figure 2 Engine speed (Ne) Figure 5

Claims (1)

[Claims] In an internal combustion engine having a plurality of independent combinations of intake passages and exhaust passages, a turbocharger is disposed in each set of the intake passage and exhaust passage, and each exhaust passage in which a turbine of the turbocharger is disposed. The upstream sides of the turbines are connected to each other by an exhaust side communication passage, and an on-off valve is disposed in this exhaust side communication passage, while the compressor downstream side of each intake passage in which the compressor of the turbocharger is disposed is connected to an intake side communication passage. These passages are interconnected with each other and connected to the downstream side of the exhaust side communication passage of some sets of exhaust passages among the exhaust passages and the upstream side of the intake side communication passage of the intake passages that are paired with the part of the exhaust passages. An internal combustion engine equipped with a turbocharger, which is characterized in that it is equipped with on-off valves that open and close with each other.