JPH1030446A - Supercharger for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the loss of suction and exhaust and the degradation of fuel consumption in a running region of gas flow rate exceeding a predetermined valve by connecting two turbines to a turbo coaxially with a compressor while making exhaust paths separatively formed into two systems communicate to each other through a communicating passage having a valve interposed therein. SOLUTION: During running of an engine, the detecting signals of a rotation sensor and load sensor are read in a controller 16 to judge whether or not it corresponds to a valve opening region on a control map on the basis of these signals. A valve 15 is closed in the running region of small gas flow rate to a turbine 4 and opened when the gas flow rate exceeds a predetermined value. When the valve 15 is closed to intercept a communicating passage 14, exhaust from No.1-3 cylinders and No.4-6 cylinders flows individually into turbines 4a, 4b respectively through exhaust passages 10, 11, so that the exhaust pressure is avoided from the mutual interference, and the rotation of the turbine with low speed is improved. On the other hand, when the valve 15 is opened, the respective exhaust joins together through the communicating passage 14, so that the exhaust pressure in the upstream of the turbines 4a, 4b is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a supercharger for an engine.

[0002]

2. Description of the Related Art As a supercharging device for an engine, there is well known a turbocharger in which a turbine is driven by exhaust energy of the engine and the turbine drives a compressor to supercharge the intake air of the engine. . Among them, in a multi-cylinder engine, in order to improve turbine rotation at low speed by using exhaust pulsation, two turbines are connected to a turbo coaxially with a compressor, and an exhaust passage on the downstream side is divided into two systems. There is an example in which the pressure of exhaust gas is prevented from interfering with each other (Japanese Patent Laid-Open No. Hei 8-28).
286).

[0003]

When the exhaust system is tuned in this way, an A characteristic as shown in FIG. 4 is obtained. Compared with the B characteristic corresponding to the case where tuning is not performed, in the operating region where the gas flow rate to the turbine is small, the dynamic effect of the exhaust is utilized, and the energy transmission to the turbine is improved, so that the intake and exhaust loss of the engine and the Although the fuel efficiency is improved, the exhaust pressure upstream of the turbine increases when the gas flow rate exceeds a predetermined value when the gas flow rate exceeds a predetermined value. There is a tendency to worsen the fuel efficiency.

The present invention has been made in view of such problems, and realizes a multi-cylinder engine with a turbocharger which has a small intake and exhaust loss and good fuel efficiency even in an operation region where the gas flow rate to the turbine exceeds a predetermined value. With the goal.

[0005]

According to a first aspect of the present invention, in a multi-cylinder engine with a turbo, two turbines are connected to a turbo coaxially with a compressor to avoid interference between exhaust pressures of the turbines. For this purpose, an exhaust passage is formed separately in two systems, and a passage connecting these exhaust passages to each other, a valve for opening and closing this communication passage, and means for controlling the opening and closing according to the engine operating state are provided.

According to a second aspect of the present invention, in a multi-cylinder engine provided with a twin scroll turbo, an exhaust passage on the downstream side of the turbo is divided and formed into two systems in order to prevent interference between exhaust pressures of two turbine scrolls. A passage for communicating these exhaust passages with each other, a valve for opening and closing the communication passage, and a means for controlling the opening and closing of the passage in accordance with an engine operating state.

According to a third aspect of the present invention, in the first or second aspect, the valve control means includes means for detecting an engine speed and a load as an engine operation state, and a predetermined means based on these detection signals. A controller is provided for controlling the valve to open in a high-speed high-load region and close the valve in other operation regions.

[0008]

FIG. 1 shows an example of application to a V-type six-cylinder engine. A compressor 3 of a turbo 2 is interposed in an intake passage 1 of the engine. The turbo 2 drives the compressor 3 by rotating the turbine 4 with the exhaust energy of the engine, and supercharges the intake air of the engine. In this example, two turbines 4 a and 4 b are connected coaxially with the compressor 3.

The supply air from the compressor 3 is supplied to an intake manifold 6 through an aftercooler 5, and is introduced into each cylinder 7 (cylinder) of both banks. It should be noted that cylinders # 1 to # 3 that do not interfere with intake and exhaust are arranged in one bank, and cylinders # 4 to # 6 that do not interfere with intake and exhaust are arranged in the other bank.

The exhaust system of the engine is divided into two exhaust passages 10 and 11 corresponding to each bank. Reference numeral 12 denotes an exhaust manifold for collecting the exhaust of the first to third cylinders, and 1
Reference numeral 3 denotes an exhaust manifold for collecting the exhaust of the fourth to sixth cylinders, and these manifolds 12 and 13 are connected to turbines 4a and 4b, respectively.

A passage 14 communicating between the two exhaust passages 10 and 11 is formed near the entrance of the turbine 4, and a valve 15 for opening and closing the communication passage 14 is provided. The controller 16 controls the opening and closing of the valve 15 and is constituted by a microcomputer.
5 is opened and the valve 15 is closed otherwise.

Although not shown, a rotation sensor for detecting the rotation speed of the engine and a load sensor for detecting the load of the engine (accelerator opening) are provided. A control map as shown in FIG. 2 is stored in the memory of the controller 16. In this map, the closed area and the open area of the valve 15 are set based on the gas flow rate corresponding to the intersection P between the A characteristic and the B characteristic in FIG.

FIG. 3 is a flow chart for explaining the control contents of the controller 16. In FIG. 3, the detection signals of the engine rotation sensor and the load sensor are read, and based on these detection signals, it is determined whether or not the engine corresponds to the valve opening area on the control map. A judgment is made (Step 1 and Step 2). Control is performed so that the valve 15 is opened when the valve is in the valve-opening region, and is closed when the valve is not in the valve-opening region (steps 3 and 4).

With this configuration, the valve 15 is closed in an operation region where the gas flow rate to the turbine 4 is small, and the gas flow rate to the turbine 4 is reduced to a predetermined value (corresponding to the intersection P between the A characteristic and the B characteristic in FIG. 4). Gas flow rate), the valve 1
5 is opened.

When the valve 15 is closed and the communication passage 14 is shut off, the exhaust of the first to third cylinders and the exhaust of the fourth to sixth cylinders pass through the exhaust passages 10 and 11, respectively.
Flows separately to 4b. For this reason, it is possible to prevent the exhaust pressures from interfering with each other, thereby improving low-speed turbine rotation. When the valve 15 is opened, the first to third cylinders and the fourth to sixth cylinders
Since the exhaust of the cylinder No. joins through the communication passage, the exhaust pressure upstream of the turbines 4a and 4b decreases due to expansion of the passage volume and interference of the exhaust.

For this reason, in the operation region where the gas flow rate to the turbine 4 is small, the characteristic A in FIG.
When the gas flow rate exceeds the predetermined value, the characteristic is switched to the B characteristic shown in FIG. 4, so that the intake and exhaust loss can be reduced and the fuel efficiency can be improved in a wide operating range of the engine.

The turbo 2 may be of a twin scroll type in which the scroll of the turbine housing is separated into two systems. 5 to 6, an example of application to a multi-cylinder engine including the twin scroll turbo 20 will be described.

In the case of the four-cylinder engine shown in FIG.
An exhaust passage 10 that collects the first and fourth cylinders is connected to one of the two scrolls, and an exhaust passage 11 that collects the second and third cylinders is connected to the other scroll of the turbine 22. There is provided a passage 14 for communicating the passages 10 and 11 with each other, and a valve 15 for opening and closing the passage 14. Then, by a controller not shown,
The valve 15 is controlled as in FIG.

In the case of the in-line six-cylinder engine shown in FIG. 6, an exhaust passage 10 for collecting the first to third cylinders is provided in one scroll of the turbine 22, and the fourth to sixth cylinders are provided in the other scroll of the turbine 22. 11 are respectively connected.
The valve 15 is controlled by a controller (not shown) so as to open and close the communication passage 14 of the exhaust passages 10 and 11 as in FIG.

In the case of the V-type 8-cylinder engine shown in FIG. 7, the intake system is also formed separately in the passage 1 for each bank, and the two turbochargers 20
Is arranged. In the left bank, the exhaust passage 10 that collects the first cylinder and the fifth cylinder in one scroll of the turbine 22 has the 3rd scroll in the other scroll of the turbine 22.
Exhaust passages 11 that collect the cylinder No. 7 and the cylinder No. 7 are connected respectively. In the right bank, an exhaust passage 10 that collects the second cylinder and the fourth cylinder in one scroll of the turbine 22, and an exhaust passage 11 that collects the sixth cylinder and the eighth cylinder in the other scroll of the turbine 22, respectively. Connected.

A passage 14 for communicating the exhaust passages 10 and 11 of each bank and a valve 15 for opening and closing the communication passage 14 are provided.
Are controlled in the same manner as in FIG.

5 to 7, reference numeral 1 denotes an intake passage of the engine, and 21 denotes a turbo compressor.

[0023]

According to the first aspect of the present invention, in a multi-cylinder engine with a turbo, two turbines are connected to the turbo coaxially with the compressor, and the exhaust gas is exhausted to avoid interference between the exhaust pressures of the turbines. A passage is formed in two separate systems, and a passage for communicating these exhaust passages with each other, a valve for opening and closing this communication passage, and a means for controlling the opening and closing according to the engine operating state are provided. Thus, the intake and exhaust loss can be reduced and the fuel efficiency can be improved.

According to the second aspect of the present invention, in a multi-cylinder engine provided with a twin scroll turbo, the exhaust passage on the downstream side of the turbo is divided into two systems in order to prevent interference between exhaust pressures to the two turbine scrolls. Forming
A passage communicating these exhaust passages with each other, a valve for opening and closing the communication passage, and a means for controlling the opening and closing of the passage in accordance with an engine operating condition are provided. The fuel consumption rate can be improved by reducing the intake and exhaust loss.

According to a third aspect, in the first aspect or the second aspect, the valve control means includes means for detecting an engine speed and a load as an engine operation state, and based on these detection signals. The valve is controlled to open the valve in a predetermined high-speed and high-load region and close the valve in other operation regions. The fuel consumption rate can be improved by reducing the intake and exhaust loss.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an embodiment of the present invention.

FIG. 2 is a characteristic diagram of a control map.

FIG. 3 is a flowchart illustrating the control contents of a controller.

FIG. 4 is a characteristic diagram showing a relationship between an opening / closing state of a valve, an intake / exhaust loss, and a fuel efficiency.

FIG. 5 is a schematic diagram illustrating an example of application to a four-cylinder engine.

FIG. 6 is a schematic diagram illustrating an example of application to a six-cylinder engine.

FIG. 7 is a schematic diagram illustrating an example of application to an eight-cylinder engine.

[Description of Signs] 1 Intake passage 2 Dual turbine type turbo 3 Compressor 4, 4a, 4b Turbine 6 Intake manifold 7 Cylinder (cylinder) 10, 11 Exhaust passage 12, 13 Exhaust manifold 14 Communication passage 15 Valve 16 Controller 20 Twin scroll turbo

Claims (3)

[Claims] In a multi-cylinder engine with a turbo, two turbines are connected to a turbo coaxially with a compressor, and an exhaust passage is formed in two systems so as to avoid interference between exhaust pressures of the turbines. A supercharger for an engine, comprising: a passage connecting the exhaust passages to each other; a valve for opening and closing the communication passage; 2. In a multi-cylinder engine having a twin scroll turbo, an exhaust passage on the downstream side of the turbo is divided and formed into two systems so as to avoid interference between exhaust pressures of two turbine scrolls. And a valve for opening and closing the communication passage, and means for controlling the opening and closing of the communication passage in accordance with the engine operating state. 3. The valve control means includes means for detecting a rotational speed and a load of the engine as an engine operation state, and opening the valve in a predetermined high-speed and high-load area based on the detection signals and operating in other operation areas. A controller for controlling the valve to close the valve.
Or the supercharging device according to claim 2.