JP6235378B2 - Supercharged internal combustion engine - Google Patents

Description

  The present invention relates to a technical field of a supercharged internal combustion engine having a plurality of cylinders having an overlap period when an exhaust valve is open.

  Many large engines such as marine diesel engines are equipped with a turbocharger or the like in order to improve engine efficiency. The air supplied to the engine is compressed and heated by a supercharger driven by exhaust gas energy, and then cooled by an intercooler to be supplied to each cylinder as scavenging.

  Exhaust gas from each cylinder is sent to the supercharger based on the differential pressure between the scavenging side pressure and the exhaust side pressure when the exhaust valve is opened. In general, an engine has a plurality of cylinders, and exhaust gas from each cylinder is collected by an exhaust manifold and supplied to a supercharger. However, there is an overlap period when the exhaust valve of each cylinder is open. In some cases, due to the influence between the cylinders via the exhaust manifold, the exhaust side pressure becomes larger than the scavenging side pressure, and a back flow phenomenon may occur in which the exhaust gas flows back to the cylinder side.

  In order to prevent such a backflow phenomenon of exhaust gas, for example, in Patent Document 1, exhaust gas discharged from each cylinder is temporarily stored in a static pressure chamber (surge tank), and the dynamic pressure of the exhaust gas is increased. It is static pressure.

JP2013-60919A

  In the above-mentioned Patent Document 1, there is a problem that a large pressure loss occurs in the process in which the exhaust gas from each cylinder is supplied from the exhaust pipe to the exhaust static pressure chamber (for example, the pressure loss coefficient at the outlet of the exhaust pipe is 1. If the exhaust gas has a potential core, the exhaust gas collides with the wall surface of the exhaust static pressure chamber, resulting in a pressure loss coefficient of 1 or more. For this reason, due to the energy reduction of the exhaust gas, the work of the turbocharger is reduced and sufficient engine efficiency cannot be obtained.

  As a measure for reducing the pressure loss of the exhaust gas, it is worth considering a dynamic pressure supercharging system in which the exhaust pipe is directly connected to the turbocharger without using the exhaust static pressure chamber. However, in an engine having three or more cylinders, there is an overlap in the opening period of the exhaust valve, so the occurrence of the above-described backflow phenomenon becomes a problem.

  The present invention has been made in view of the above-described problems. Even when there is an overlap in the exhaust valve open period of a plurality of cylinders, the supercharger can prevent the backflow of exhaust gas to the cylinder side. An object of the present invention is to provide a supercharged internal combustion engine having excellent engine efficiency by supercharging dynamic pressure.

  In order to solve the above problems, a supercharged engine according to an aspect of the present invention includes a first cylinder that discharges exhaust gas, and a second cylinder in which the opening period of the first cylinder and the exhaust valve overlap. A supercharged internal combustion engine that supercharges the plurality of cylinders by supplying the exhaust gas to a supercharger, wherein the exhaust ports of the plurality of cylinders are arranged in parallel An exhaust manifold to be connected; a plurality of first connection pipes connecting both ends of the exhaust manifold to the supercharger; and a first opening adjustment valve provided in each of the plurality of first connection pipes And a control unit that controls the opening of the opening adjustment valve, and a plurality of throttle portions provided between a plurality of connection portions that connect the plurality of exhaust ports to the exhaust manifold, respectively. Is the exhaust discharged from the first cylinder. As gas is supplied to the second of said supercharger via a connecting portion corresponding to the cylinder, and controls the first opening adjustment valve.

  According to this aspect, the exhaust gas discharged from the first cylinder is supplied to the supercharger via the connection portion corresponding to the second cylinder. When the exhaust gas passes through the connection portion corresponding to the second cylinder, the flow rate is increased by the throttle portion provided in the exhaust manifold, thereby obtaining a carburetor effect (venturi effect). Thereby, it is possible to prevent a backflow phenomenon in which the exhaust gas discharged from the first cylinder flows back to the second cylinder whose open period overlaps with the first cylinder. Further, the exhaust gas flowing through the exhaust manifold is supplied to the supercharger without increasing the dynamic pressure by increasing the flow velocity by the plurality of throttle portions, and without reducing the static pressure. Therefore, the energy of the exhaust gas is given to the turbocharger with a small pressure loss, and good engine efficiency can be obtained. In other words, because the engine efficiency is excellent, it is also advantageous for engine downsizing.

The plurality of throttle portions are configured such that the degree of throttle is variable, and the control unit has a range within which the exhaust gas discharged from the first cylinder of the exhaust manifold passes among the plurality of throttle portions. You may make it control the aperture degree of the provided diaphragm | throttle part largely compared with another diaphragm | throttle part.
According to this aspect, the advantage of the carburetor effect (the Venturi effect) as described above is obtained by increasing the throttle degree of the throttle portion located in the exhaust gas flow range in the exhaust manifold. On the other hand, by reducing the degree of throttling of the other throttling portions, it is avoided that it becomes a cause of pressure loss of the exhaust gas. Thereby, exhaust energy can be efficiently supplied to the supercharger.

  A second connecting pipe that connects the plurality of connecting sections to the supercharger; and a second opening adjustment valve that is provided in the second connecting pipe, and the control section includes the first connecting section The exhaust gas discharged from the first cylinder is supplied to the supercharger through a connection corresponding to the second cylinder, and the flow path length of the first exhaust gas is minimized. The opening degree adjusting valve and the second opening degree adjusting valve may be controlled.

  For example, depending on the number of cylinders of the internal combustion engine, the pressure loss may increase due to a long exhaust path to the supercharger. In this aspect, even in such a case, the exhaust flow is provided by including the second connection pipe that connects the connection portions to the supercharger and the second opening adjustment valve for the second connection pipe. The route selection is performed so that the route becomes the shortest. This makes it possible to select a route with less pressure loss in addition to the above-described effect, thereby realizing a more efficient supercharged internal combustion engine.

In this case, there may be two or more second cylinders.
When there are two or more second cylinders as in this aspect, that is, in three or more cylinders including the first cylinder, when there is an overlap in the open period of the exhaust valves, the exhaust path becomes long. In view of the above, an aspect including the second connecting pipe and the second opening degree adjusting valve as described above is suitable.

In addition, a load detection unit that detects a load of the internal combustion engine may be provided, and the control unit may variably control the throttle degree of the throttle unit based on the load detected by the load detection unit. .
Generally, when the load on the internal combustion engine is small, the flow rate of the exhaust gas decreases, so the dynamic pressure of the exhaust gas supplied to the supercharger also decreases. Therefore, in this aspect, the load of the internal combustion engine is detected by providing the load detection unit, and the throttle rate of the throttle unit is variably controlled based on the detected value, so that the flow rate of the exhaust gas is appropriately increased by the throttle unit. The exhaust gas can be efficiently supplied to the supercharger.

  According to the present invention, the exhaust gas discharged from the first cylinder is supplied to the supercharger via the connection corresponding to the second cylinder. When the exhaust gas passes through the connection portion corresponding to the second cylinder, the flow rate is increased by the throttle portion provided in the exhaust manifold, thereby obtaining a carburetor effect (venturi effect). Thereby, it is possible to prevent a backflow phenomenon in which the exhaust gas discharged from the first cylinder flows back to the second cylinder whose open period overlaps with the first cylinder. Further, the exhaust gas flowing through the exhaust manifold is supplied to the supercharger without increasing the dynamic pressure by increasing the flow velocity by the plurality of throttle portions, and without reducing the static pressure. Therefore, the energy of the exhaust gas is given to the turbocharger with a small pressure loss, and good engine efficiency can be obtained.

It is sectional drawing which shows the structural example of the supercharged engine which concerns on 1st Embodiment. It is a schematic diagram which shows the exhaust path between the exhaust ports of several cylinders, and a turbocharger in a 4-cylinder engine. It is sectional drawing which expands and shows the vicinity of the throttle part of an exhaust manifold. It is a mimetic diagram showing roughly the composition near the exhaust passage of the engine concerning a 1st embodiment. It is a timing chart which shows the opening-and-closing period of the exhaust valve in each cylinder of the engine concerning a 1st embodiment. It is a schematic diagram which shows the flow of the exhaust gas of the exhaust passage in each period shown in FIG. It is a mimetic diagram showing roughly the composition near the exhaust passage of the engine concerning a 2nd embodiment. It is a timing chart which shows the opening-and-closing period of the exhaust valve in each cylinder of the engine concerning a 2nd embodiment. It is a schematic diagram which shows the flow of the exhaust gas of the exhaust passage in each period shown in FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail. The present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are essential as means for solving the present invention. Not necessarily.

(First embodiment)
FIG. 1 is a cross-sectional view showing a structural example of an engine 100 according to the first embodiment. The engine 100 is a large diesel engine for ships, and is a uniflow two-cycle multi-cylinder engine. A cylinder liner 4 is provided inside a cylinder jacket 3 installed on the frame 2, and a cylinder head 5 is provided at the upper end thereof. A cylinder bore 6 is formed in the cylinder liner 4, and a piston 7 is slidably inserted into the cylinder bore 6. The piston 7 is connected to the piston rod 8. The lower end of the piston rod 8 is connected to the crankshaft via a cross head and a connecting rod (not shown).

  A plurality of scavenging ports 11 are formed in the circumferential direction in the lower part of the cylinder liner 4. A scavenging passage 12 is defined in the cylinder jacket 3 so as to surround the scavenging ports 11. On the other hand, an exhaust port 13 and an exhaust valve 14 for opening and closing the exhaust port 13 are provided at the top of the cylinder head 5. The exhaust valve 14 is driven to open and close by a camshaft (not shown) or an electromagnetically controlled hydraulic device, and opens in synchronism with the timing when the piston 7 moves up in the cylinder bore 6.

  The exhaust ports 13 of the plurality of cylinders of the engine 100 are connected to the turbocharger 18 via the exhaust path 20 respectively. Here, FIG. 2 is a schematic diagram showing an exhaust path 20 between the exhaust ports 13 of the plurality of cylinders and the turbocharger 18 in the four-cylinder engine 100. In FIG. 2, the exhaust ports 13a, 13b, and 13c corresponding to the cylinders 1a, 1b, 1c, and 1d of the engine 100 (in the following description, they are indicated by reference numeral 1 when referring to all the cylinders collectively). In the following description, character codes a, b, c, and d that are common to the configurations corresponding to the respective exhaust ports 13 are appropriately attached.

The exhaust path 20 includes an exhaust manifold 25 that connects the exhaust ports 13 of the four cylinders in parallel, and two connections that connect different positions on the exhaust manifold 25 to the exhaust turbine side flow path 19 of the turbocharger 18. It consists of tubes 26a and 26b. The exhaust manifold 25 forms exhaust ports 13a, 13b, 13c and 13d and connecting portions 27a, 27b, 27c and 27d. Between the connecting portions 27a, 27b, 27c and 27d, throttle portions 28a, 28b and 28c for regulating the flow rate of the exhaust gas in the exhaust manifold 25 are provided.
The two connecting pipes 26a and 26b are examples of the “first connecting pipe” according to the present invention.

  FIG. 3 is an enlarged sectional view showing the vicinity of the throttle portion 28 of the exhaust manifold 25. The throttle portion 28 is formed in a convex shape so as to protrude from the inner wall of the exhaust manifold 25 having a cylindrical cross section, and the protruding state is variably configured by a control unit 30 described later. By providing the throttle portion 28 in the exhaust manifold 25 as described above, the flow rate of the exhaust gas flowing in the exhaust manifold 25 is increased when passing through the throttle portion 28 as indicated by an arrow in FIG.

  The two connection pipes 27a and 27b are respectively connected to both end sides of the exhaust manifold 25 (connected to both sides of the throttle portions 28a, 28b, and 28c). Valves 29a and 29b, which are examples of the “first opening adjustment valve” of the present invention, are provided on the two connection pipes 27a and 27b, respectively. It is configured to be selectable.

  The intake turbine side flow path 17 of the turbocharger 18 is connected to the scavenging passage 12 via an air conduit 22 having a substantially U-shaped vertical cross-sectional shape. An air cooler (intercooler) 23 is installed inside the air conduit 22.

  When the engine 100 is in operation, high-temperature and high-pressure exhaust gas flows through the exhaust path 20 to the exhaust turbine side passage 19 of the turbocharger 18, and the exhaust turbine of the turbocharger 18 is rotationally driven. As a result, outside air is taken into the turbocharger 18 and compressed and heated, and then cooled by the air cooling air 23 through the intake turbine side flow path 17 and enters the scavenging port 12 as scavenging.

  Next, the control contents of the engine 100 having the above configuration will be described with reference to FIGS. 4 to 6. FIG. 4 is a schematic diagram schematically showing the configuration in the vicinity of the exhaust passage 20 of the engine 100 according to the first embodiment, and FIG. 5 shows the opening / closing period of the exhaust valve 14 in each cylinder of the engine 100 according to the first embodiment. FIG. 6 is a schematic diagram showing the flow of exhaust gas in the exhaust passage 20 in each period shown in FIG.

First, as shown in FIG. 4, the engine 100 includes a control unit 30 that is a control unit for controlling the movable part of the exhaust passage 20. The control unit 30 is a control unit for variably controlling the throttle degree of the throttle unit 28 in the exhaust path and the open / closed state of the valve 29 in accordance with the operating state of the engine 100.
The control unit 30 may also serve as another control unit included in the engine 100 such as an ECU.

Subsequently, as shown in FIG. 5, the exhaust valves 14a, 14b, 14c and 14d corresponding to the cylinders 1a, 1b, 1c and 1d each have an open period of 150 degrees during one cycle (360 degrees). The overlap period exists in the open period of any two exhaust valves 14. That is, in the present embodiment, there is one first cylinder in which the exhaust valve 14 is opened to exhaust the exhaust gas, and the first cylinder having the exhaust valve 14 having an overlap period with the first cylinder. This corresponds to the case where there is one 2 cylinder.
In FIG. 6, in order to clearly show the open / closed state of the exhaust valve 14 in each of the cylinders 1a, 1b, 1c and 1d, the cylinders in which the exhaust valve 14 is closed are indicated by hatching.

  Here, the opening period of each exhaust valve 14 is set so as to be shifted by 90 degrees in order to make the rotation of the engine output shaft uniform. In the following description, as shown in FIG. 5, one cycle is divided into four periods (a), (b), (c), and (d).

  First, in period (a), exhaust gas is discharged from the exhaust port 13c by opening the exhaust valve 14c of the cylinder 1c, which is the first cylinder, and the exhaust valve 14b of the cylinder 1b, which is the second cylinder, is opened. Thus, scavenging is taken into the cylinder 1b from the scavenging port 12b using the differential pressure between the scavenging pressure and the exhaust pressure. That is, in the period (a), there is an overlap period in the exhaust valves 14b and 14c. At this time, as shown in FIG. 6A, the control unit 30 switches the valve 27a to the open state and switches the valve 27b to the closed state, so that the exhaust gas discharged from the cylinder 1c passes through the connecting pipe 26a. Then, it flows into the exhaust turbine side flow path 19 of the turbocharger 18.

  At this time, the control unit 30 controls the exhaust degree of the throttle unit 28b provided in the range through which the exhaust gas discharged from the cylinder 1c of the exhaust manifold 25 passes to be larger than that of the other throttle units, thereby In the connecting portion 27b corresponding to the cylinder 1b in which the valve 14b is open, the flow rate of the exhaust gas flowing through the exhaust manifold 25 is increased, and the dynamic pressure of the exhaust gas supplied to the turbocharger 18 is improved. On the other hand, the exhaust gas flowing through the scavenging manifold 25 has a negative pressure acting on the exhaust pressure of the cylinder 1b due to the carburetor effect (venturi effect), and the scavenging intake is promoted. That is, the backflow of the exhaust gas to the cylinder 1b in which the exhaust valve 14b is open is prevented, and the scavenging suction in the cylinder 1b is promoted.

  Subsequently, in the period (b), exhaust gas is discharged from the exhaust port 13a by opening the exhaust valve 14a of the cylinder 1a which is the first cylinder, and the exhaust valve 14c of the cylinder 1c which is the second cylinder is opened. Thus, scavenging is taken into the cylinder 1c from the scavenging port 12c using a differential pressure between the scavenging pressure and the exhaust pressure. That is, in the period (b), there is an overlap period in the exhaust valves 14a and 14c. At this time, as shown in FIG. 6B, the control unit 30 switches the valve 27a to the closed state and switches the valve 27b to the open state, so that the exhaust gas discharged from the cylinder 1a passes through the connecting pipe 26b. Then, it flows into the exhaust turbine side flow path 19 of the turbocharger 18.

  At this time, the control unit 30 controls the throttle degree of the throttle parts 28a and 28b provided in the range through which the exhaust gas discharged from the cylinder 1a of the exhaust manifold 25 passes is larger than that of the other throttle parts. In the connecting portion 27c corresponding to the cylinder 1c in which the exhaust valve 14c is open, the flow rate of the exhaust gas flowing through the exhaust manifold 25 is increased, and the dynamic pressure of the exhaust gas supplied to the turbocharger 18 is improved. On the other hand, the exhaust gas flowing through the scavenging manifold 25 has a negative pressure acting on the exhaust pressure of the cylinder 1c due to the carburetor effect (venturi effect), and the intake of scavenging is promoted. That is, the backflow of the exhaust gas to the cylinder 1c in which the exhaust valve 14c is open is prevented, and the scavenging suction in the cylinder 1c is promoted.

  Subsequently, in period (c), exhaust gas is discharged from the exhaust port 13d by opening the exhaust valve 14d of the cylinder 1d, which is the first cylinder, and the exhaust valve 14a of the cylinder 1a, which is the second cylinder, is opened. Thus, scavenging is taken into the cylinder 1a from the scavenging port 12a using a differential pressure between the scavenging pressure and the exhaust pressure. That is, in the period (c), there is an overlap period in the exhaust valves 14a and 14d. At this time, as shown in FIG. 6C, the control unit 30 switches the valve 27a to the open state and switches the valve 27b to the closed state, so that the exhaust gas discharged from the cylinder 1d passes through the connection pipe 26a. Then, it flows into the exhaust turbine side flow path 19 of the turbocharger 18.

  At this time, the control unit 30 controls the throttle degree of the throttle parts 28a, 28b and 28c provided in the range through which the exhaust gas discharged from the cylinder 1d of the exhaust manifold 25 passes is larger than that of the other throttle parts. As a result, the flow rate of the exhaust gas flowing through the exhaust manifold 25 is increased at the connection portion 27a corresponding to the cylinder 1a where the exhaust valve 14a is open, and the dynamic pressure of the exhaust gas supplied to the turbocharger 18 is improved. On the other hand, the exhaust gas flowing through the scavenging manifold 25 has a negative pressure acting on the exhaust pressure of the cylinder 1a due to the carburetor effect (venturi effect), and the scavenging intake is promoted. That is, the backflow of the exhaust gas to the cylinder 1a in which the exhaust valve 14a is open is prevented, and the scavenging suction in the cylinder 1a is promoted.

  Subsequently, in the period (d), exhaust gas is discharged from the exhaust port 13b by opening the exhaust valve 14b of the cylinder 1b that is the first cylinder, and the exhaust valve 14d of the cylinder 1d that is the second cylinder is opened. Thus, scavenging is taken into the cylinder 1d from the scavenging port 12d using a differential pressure between the scavenging pressure and the exhaust pressure. That is, in the period (d), there is an overlap period in the exhaust valves 14b and 14d. At this time, as shown in FIG. 6C, the control unit 30 switches the valve 27a to the closed state and switches the valve 27b to the open state, so that the exhaust gas discharged from the cylinder 1b passes through the connecting pipe 26b. Then, it flows into the exhaust turbine side flow path 19 of the turbocharger 18.

  At this time, the control unit 30 controls the throttle degree of the throttle parts 28b and 28c provided in the range through which the exhaust gas discharged from the cylinder 1b of the exhaust manifold 25 passes is larger than that of the other throttle parts. In the connecting portion 27d corresponding to the cylinder 1d in which the exhaust valve 14d is open, the flow rate of the exhaust gas flowing through the exhaust manifold 25 is increased, and the dynamic pressure of the exhaust gas supplied to the turbocharger 18 is improved. On the other hand, the exhaust gas flowing through the scavenging manifold 25 has a negative pressure acting on the exhaust pressure of the cylinder 1d due to the carburetor effect (venturi effect), and the intake of scavenging is promoted. That is, the backflow of the exhaust gas to the cylinder 1d in which the exhaust valve 14d is open is prevented, and the scavenging suction in the cylinder 1d is promoted.

  Thus, even when the plurality of exhaust valves have overlap periods in each of the periods (a) to (d), the backflow phenomenon of the exhaust gas to the cylinder is prevented and the exhaust manifold 25 The dynamic pressure is increased by the throttle portion. As a result, since the exhaust gas discharged from each cylinder can be supplied to the turbocharger 18 with a small pressure loss, good engine efficiency can be obtained.

In the case of an engine using the conventional exhaust static pressure chamber shown in Patent Document 1, as a pressure loss element,
A pressure loss coefficient of 1 or more is generated at the outlet portion of the exhaust pipe to the exhaust static pressure chamber, and a pressure loss coefficient of 0.5 or more is generated from the exhaust static pressure chamber to the well portion of the exhaust turbine side flow path. Therefore, in the prior art, although the backflow of exhaust gas to the cylinder can be prevented by static pressure, a pressure loss coefficient of at least 1.5 or more occurs in the entire exhaust passage.

  On the other hand, in the engine of this embodiment, as a pressure loss element, (i) pressure loss caused by exhaust gas colliding with an inner wall at a curved portion connected to the pipe 19 on the downstream side of the valve 29, and (ii) a throttle portion There is a pressure loss due to the sudden contraction of the exhaust gas by 28. The former pressure loss corresponds to a pressure loss coefficient of 0.4 at the maximum although it depends on the pipe shape. The pressure loss due to the latter corresponds to a pressure loss coefficient of 0.3 per throttle portion 28 assuming that each throttle portion 28 is throttled to a cross-sectional opening ratio of 0.6 or more of the exhaust manifold 25. Therefore, when one throttle part 28 is operated, the pressure loss generated in the entire exhaust passage 20 is about 0.7, and it was verified that the pressure loss can be significantly reduced as compared with the conventional case.

  By passing the throttle portion 28, the flow rate of the exhaust gas in the exhaust manifold 25 increases 1.3 times, and the dynamic pressure increases 1.7 times.

  In the above description, the apertures of the apertures 28a, 28b, and 28c are variable by the control unit 30, but may be fixed to a predetermined aperture. In this case, pressure loss due to the three throttle portions 28a, 28b, and 28c always occurs, but an advantageous effect can be obtained as much as dynamic pressure can be supplied as compared with the above-described conventional technology.

  In addition, a load sensor that detects the load state of the engine 100 may be installed, and the control unit 30 may control the aperture of the aperture units 28a, 28b, and 28c based on the detection value of the load sensor. For example, when the load is small, the pressure of the exhaust gas discharged from each cylinder decreases, so that the dynamic pressure supplied to the turbocharger 18 also tends to decrease. At this time, the throttle degree of the throttle unit 28 is increased. By controlling to, dynamic pressure can be increased.

(Second Embodiment)
In the above-described first embodiment, the case where the engine 100 has four cylinders has been described. Here, an example in which the present invention is applied to a seven-cylinder engine 100 ′ will be described. The basic configuration of the engine 100 'is the same as that of the engine 100, and common portions are denoted by the same reference numerals, and redundant description is appropriately omitted.

FIG. 7 is a schematic view schematically showing a configuration in the vicinity of the exhaust passage 20 of the engine 100 ′ according to the second embodiment, and FIG. 8 is a diagram showing opening and closing of the exhaust valve 14 in each cylinder of the engine 100 ′ according to the second embodiment. 9 is a timing chart showing periods, and FIG. 9 is a schematic diagram showing the flow of exhaust gas in the exhaust passage 20 in each period shown in FIG.
In this modification, the letter symbols a, b, c, d, e, f, and g are given when distinguishing the components corresponding to the cylinders of the engine 100 ′. Similarly to FIG. 6 described above, in order to clearly show the open / closed state of the exhaust valve 14 in each cylinder, the cylinder in which the exhaust valve 14 is closed is indicated by hatching.

  The exhaust path 20 includes an exhaust manifold 25 that connects the exhaust ports 13 of the seven cylinders in parallel, and three connections that connect different positions on the exhaust manifold 25 to the exhaust turbine side flow path 19 of the turbocharger 18. It consists of tubes 26a, 26b and 26c. The connection pipes 26a and 26b common to the first embodiment are examples of the “first connection pipe” of the present invention as described above, and the connection pipe 26c added in the present embodiment is the “second connection pipe” of the present invention. Is an example.

  The exhaust manifold 25 forms exhaust ports 13a, 13b, 13c, 13d, 13e, 13f and 13g and connecting portions 27a, 27b, 27c, 27d, 27e, 27f and 27g. Between the connecting portions 27a, 27b, 27c, 27d, 27e, 27f and 27g, throttle portions 28a, 28b, 28c, 28d, 28e and 28f for regulating the flow rate of the exhaust gas in the exhaust manifold 25 are provided. It has been. Similarly to the first embodiment, the connection pipes 27a and 27b are connected to both ends of the exhaust manifold 25, and the connection pipe 27c is one of the connection portions 27a, 27b, 27c, 27d, 27e, 27f, and 27g. Connected between.

  Valves 29a, 29b and 29c are provided on the three connecting pipes 27a, 27b and 27c, respectively. As described above, the valves 29a and 29b are examples of the “first opening adjustment valve” according to the present invention, and the remaining valves 29c are examples of the “second opening adjustment valve” according to the present invention.

  Subsequently, as shown in FIG. 8, the exhaust valves 14a, 14b, 14c, 14d, 14e, 14f, and 14g corresponding to the cylinders 1a, 1b, 1c, 1d, 1e, 1f, and 1g have one cycle (360 degrees). Each has an open period of 150 degrees. Here, the open periods of the exhaust valves are shifted at intervals of 51.4 degrees (= 360 degrees / 7 cylinders) in order to make the rotation of the engine output shaft uniform, and the cylinder 1a, cylinder 1g, cylinder 1b, cylinder 1e are shifted. The cylinder 1d, the cylinder 1c, and the cylinder 1f are sequentially opened in this order. In the following description, as shown in FIG. 8, one cycle is divided into seven periods (a) (b) (c) (d) (e) (f) (g).

  First, in period (a), exhaust gas is discharged from the exhaust port 13a by opening the exhaust valve 14a of the cylinder 1a, which is the first cylinder, and the exhaust valve 14c and cylinder 1f of the cylinder 1c, which is the second cylinder. By opening the exhaust valve 14f, scavenging is taken into the cylinder 1c and the cylinder 1f from the scavenging ports 12c and 12f using the differential pressure between the scavenging pressure and the exhaust pressure. That is, in the period (a), there is an overlap period in the exhaust valves 14a, 14c and 14f. At this time, as shown in FIG. 9A, the control unit 30 switches the valves 27a and 27c to the closed state and switches the valve 27b to the open state, so that the exhaust gas discharged from the cylinder 1a is connected to the connecting pipe 26b. To the exhaust turbine side flow path 19 of the turbocharger 18.

  At this time, the control unit 30 largely controls the throttle degree of the throttle parts 28a to 28f provided in the range through which the exhaust gas discharged from the cylinder 1a of the exhaust manifold 25 passes, thereby opening the exhaust valves 14c and 14f. In the connecting portions 27c and 27f corresponding to the cylinder 1c and the cylinder 1f, the flow rate of the exhaust gas flowing through the exhaust manifold 25 is increased, and the dynamic pressure of the exhaust gas supplied to the turbocharger 18 is improved. On the other hand, the exhaust gas flowing through the scavenging manifold 25 has a negative pressure acting on the exhaust pressure of the cylinder 1c and the cylinder 1f due to the carburetor effect (venturi effect), and the scavenging intake is promoted. That is, the backflow of the exhaust gas to the cylinder 1c and the cylinder 1f in which the exhaust valves 14c and 14f are open is prevented, and the scavenging suction in the cylinder 1c and the cylinder 1f is promoted.

  Further, by flowing the exhaust gas through the connection pipe 26b in this way, the route selection is performed so that the steam carburetor effect in the other overlapping cylinders is obtained and the exhaust flow path to the turbocharger 18 is the shortest. Is called. As a result, pressure loss can be reduced in addition to the above-described effects, so that good engine efficiency can be realized.

  Subsequently, in the period (b), exhaust gas is discharged from the exhaust port 13g by opening the exhaust valve 14g of the cylinder 1g which is the first cylinder, and the exhaust valve 14a and cylinder of the cylinder 1a which is the second cylinder. By opening the exhaust valve 14f of 1f, scavenging is taken into the cylinder 1a and the cylinder 1f from the scavenging ports 12a and 12f using a differential pressure between the scavenging pressure and the exhaust pressure. That is, in the period (b), there is an overlap period in the exhaust valves 14a, 14f, and 14g. At this time, as shown in FIG. 9B, the control unit 30 switches the valves 27a and 27b to the closed state and switches the valve 27c to the open state, so that the exhaust gas discharged from the cylinder 1g is connected to the connecting pipe 26c. To the exhaust turbine side flow path 19 of the turbocharger 18.

  At this time, the control unit 30 throttles the throttle portions 28d, 28e and 28f, so that the flow rate of the exhaust gas flowing through the exhaust manifold 25 is increased in 27f corresponding to the cylinder 1f where the exhaust valve 14f is open. The dynamic pressure of the exhaust gas supplied to is improved. On the other hand, the exhaust gas flowing through the scavenging manifold 25 has a negative pressure acting on the exhaust pressure of the cylinder 1f due to the carburetor effect (venturi effect), and the scavenging intake is promoted. That is, the backflow of the exhaust gas to the cylinder 1f where the exhaust valve 14f is open is prevented, and the scavenging suction in the cylinder 1f is promoted.

  Further, by flowing the exhaust gas through the connection pipe 26c in this way, the route selection is performed so that the steam carburetor effect in other overlapping cylinders is obtained and the exhaust flow path to the turbocharger 18 is the shortest. Is called. As a result, pressure loss can be reduced in addition to the above-described effects, so that good engine efficiency can be realized.

  Subsequently, in the period (c), exhaust gas is discharged from the exhaust port 13b by opening the exhaust valve 14b of the cylinder 1b, and scavenging pressure is opened by opening the exhaust valve 14a of the cylinder 1a and the exhaust valve 14g of the cylinder 1g. Scavenging is taken into the cylinder 1a and the cylinder 1g from the scavenging ports 12a and 12g using the pressure difference between the exhaust gas and the exhaust pressure. That is, in the period (c), there is an overlap period in the exhaust valves 14a, 14b, and 14g. At this time, as shown in FIG. 9C, the control unit 30 switches the valves 27b and 27c to the closed state and switches the valve 27a to the open state, so that the exhaust gas discharged from the cylinder 1b is connected to the connecting pipe 26a. To the exhaust turbine side flow path 19 of the turbocharger 18.

  At this time, the control unit 30 throttles the throttle unit 28a, so that the flow rate of the exhaust gas flowing through the exhaust manifold 25 is increased and supplied to the turbocharger 18 at the connection unit 27a corresponding to the cylinder 1a where the exhaust valve 14a is open. The dynamic pressure of exhaust gas is improved. On the other hand, the exhaust gas flowing through the scavenging manifold 25 has a negative pressure acting on the exhaust pressure of the cylinder 1a due to the carburetor effect (venturi effect), and the scavenging intake is promoted. That is, the backflow of the exhaust gas to the cylinder 1a in which the exhaust valve 14a is open is prevented, and the scavenging suction in the cylinder 1a is promoted.

  Further, by flowing the exhaust gas through the connecting pipe 26a in this way, the route selection is performed so that the steam carburetor effect in other overlapping cylinders is obtained and the exhaust flow path to the turbocharger 18 is the shortest. Is called. As a result, pressure loss can be reduced in addition to the above-described effects, so that good engine efficiency can be realized.

  Subsequently, in period (d), exhaust gas is discharged from the exhaust port 13e by opening the exhaust valve 14e of the cylinder 1e, and scavenging pressure is opened by opening the exhaust valve 14b of the cylinder 1b and the exhaust valve 14g of the cylinder 1g. Scavenging is taken into the cylinder 1b and the cylinder 1g from the scavenging ports 12b and 12g using the pressure difference between the exhaust gas and the exhaust pressure. That is, in the period (d), there are overlap periods in the exhaust valves 14b, 14e, and 14g. At this time, as shown in FIG. 9 (d), the control unit 30 switches the valves 27a and 27c to the closed state and switches the valve 27b to the open state, so that the exhaust gas discharged from the cylinder 1e is connected to the connecting pipe 26b. To the exhaust turbine side flow path 19 of the turbocharger 18.

  At this time, the control unit 30 throttles the throttle parts 28e and 28f, so that the flow rate of the exhaust gas flowing through the exhaust manifold 25 is increased at the connection part 27g corresponding to the cylinder 1g where the exhaust valve 14g is open. The dynamic pressure of the exhaust gas supplied to is improved. On the other hand, the exhaust gas flowing through the scavenging manifold 25 has a negative pressure acting on the exhaust pressure of the cylinder 1g due to the carburetor effect (venturi effect), and the intake of scavenging is promoted. That is, the backflow of the exhaust gas to the cylinder 1g where the exhaust valve 14g is open is prevented, and the scavenging suction in the cylinder 1g is promoted.

  Further, by flowing the exhaust gas through the connection pipe 26b in this way, the route selection is performed so that the steam carburetor effect in the other overlapping cylinders is obtained and the exhaust flow path to the turbocharger 18 is the shortest. Is called. As a result, pressure loss can be reduced in addition to the above-described effects, so that good engine efficiency can be realized.

  Subsequently, in period (e), exhaust gas is discharged from the exhaust port 13d by opening the exhaust valve 14d of the cylinder 1d, and scavenging air pressure is opened by opening the exhaust valve 14b of the cylinder 1b and the exhaust valve 14e of the cylinder 1e. Scavenging is taken into the cylinder 1b and the cylinder 1e from the scavenging ports 12b and 12e using the pressure difference between the exhaust gas and the exhaust pressure. That is, in the period (e), there are overlap periods in the exhaust valves 14b, 14d, and 14e. At this time, as shown in FIG. 9 (e), the control unit 30 switches the valves 27b and 27c to the closed state and switches the valve 27a to the open state, so that the exhaust gas discharged from the cylinder 1d is connected to the connecting pipe 26a. To the exhaust turbine side flow path 19 of the turbocharger 18.

  At this time, the control unit 30 throttles the throttle portions 28a, 28b, and 28c, so that the flow velocity of the exhaust gas flowing through the exhaust manifold 25 is increased at the connection portion 27b corresponding to the cylinder 1b in which the exhaust valve 14b is open. The dynamic pressure of the exhaust gas supplied to the charger 18 is improved. On the other hand, the exhaust gas flowing through the scavenging manifold 25 has a negative pressure acting on the exhaust pressure of the cylinder 1b due to the carburetor effect (venturi effect), and the scavenging intake is promoted. That is, the backflow of the exhaust gas to the cylinder 1b in which the exhaust valve 14b is open is prevented, and the scavenging suction in the cylinder 1b is promoted.

  Further, by flowing the exhaust gas through the connection pipe 26a in this way, the route selection is performed so that the steam carburetor effect in other overlapping cylinders is obtained and the exhaust flow path to the turbocharger 18 is the shortest. Is called. As a result, pressure loss can be reduced in addition to the above-described effects, so that good engine efficiency can be realized.

  Subsequently, in period (f), the exhaust gas is discharged from the exhaust port 13c by opening the exhaust valve 14c of the cylinder 1c, and the scavenging air pressure is opened by opening the exhaust valve 14d of the cylinder 1d and the exhaust valve 14e of the cylinder 1e. Scavenging is taken into the cylinder 1d and the cylinder 1e from the scavenging ports 12d and 12e using the pressure difference between the exhaust gas and the exhaust pressure. That is, in the period (f), there are overlap periods in the exhaust valves 14c, 14d, and 14e. At this time, as shown in FIG. 9 (f), the control unit 30 switches the valves 27 a and 27 c to the closed state and switches the valve 27 b to the open state, so that the exhaust gas discharged from the cylinder 1 c is connected to the connecting pipe 26 b. To the exhaust turbine side flow path 19 of the turbocharger 18.

  At this time, the control unit 30 throttles the throttle portions 28c, 28d, 28e and 28f, so that the exhaust valves 14d and 14e flow through the exhaust manifold 25 at the connection portions 27d and 27e corresponding to the cylinder 1d and the cylinder 1e. The flow rate of the exhaust gas is increased, and the dynamic pressure of the exhaust gas supplied to the turbocharger 18 is improved. On the other hand, the exhaust gas flowing through the scavenging manifold 25 has a negative pressure acting on the exhaust pressures of the cylinders 1d and 1e due to the carburetor effect (venturi effect), and the scavenging intake is promoted. That is, the backflow of the exhaust gas to the cylinder 1d and the cylinder 1e in which the exhaust valves 14d and 14e are open is prevented, and the scavenging suction in the cylinder 1d and the cylinder 1e is promoted.

  Further, by flowing the exhaust gas through the connection pipe 26b in this way, the route selection is performed so that the steam carburetor effect in the other overlapping cylinders is obtained and the exhaust flow path to the turbocharger 18 is the shortest. Is called. As a result, pressure loss can be reduced in addition to the above-described effects, so that good engine efficiency can be realized.

  Subsequently, in period (g), exhaust gas is discharged from the exhaust port 13f by opening the exhaust valve 14f of the cylinder 1f, and scavenging air pressure is opened by opening the exhaust valve 14c of the cylinder 1c and the exhaust valve 14d of the cylinder 1d. Scavenging is taken into the cylinder 1c and the cylinder 1d from the scavenging ports 12c and 12d using a differential pressure between the exhaust gas and the exhaust pressure. That is, in the period (f), there are overlap periods in the exhaust valves 14c, 14d, and 14f. At this time, as shown in FIG. 9 (g), the control unit 30 switches the valves 27a and 27b to the closed state and switches the valve 27c to the open state, so that the exhaust gas discharged from the cylinder 1f becomes the connection pipe 26c. To the exhaust turbine side flow path 19 of the turbocharger 18.

  At this time, the control unit 30 throttles the throttle parts 28d and 28e, so that the flow rate of the exhaust gas flowing through the exhaust manifold 25 is increased at the connection part 27e corresponding to the cylinder 1e where the exhaust valve 14e is open. The dynamic pressure of the exhaust gas supplied to is improved.

  Further, by flowing the exhaust gas through the connection pipe 26c in this way, the route selection is performed so that the steam carburetor effect in other overlapping cylinders is obtained and the exhaust flow path to the turbocharger 18 is the shortest. Is called. As a result, pressure loss can be reduced in addition to the above-described effects, so that good engine efficiency can be realized.

  As described above, according to the present embodiment, the engine pressure is improved by supplying the turbocharger 18 with the increased dynamic pressure with a small pressure loss, and the backflow of the exhaust gas to the cylinder is surely prevented. Can do.

  The present invention is applicable to a supercharged internal combustion engine having a plurality of cylinders having an overlap period in an exhaust valve opening period.

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Crankcase 3 Cylinder jacket 4 Cylinder liner 5 Cylinder head 6 Cylinder bore 7 Piston 8 Piston rod 11 Scavenging port 12 Scavenging passage 13 Exhaust port 14 Exhaust valve 20 Exhaust path 25 Exhaust manifold 26 Connection pipe 27 Connection part 28 Restriction part 29 Valve 30 control device 100 (supercharged) engine

Claims (5)

A plurality of cylinders including a first cylinder that discharges exhaust gas and a second cylinder that overlaps the first cylinder and an exhaust valve open period; and supplies the exhaust gas to a supercharger A supercharged internal combustion engine that supercharges the plurality of cylinders,
An exhaust manifold connecting the exhaust ports of the plurality of cylinders in parallel;
A plurality of first connecting pipes connecting both ends of the exhaust manifold to the supercharger;
A first opening degree adjusting valve provided in each of the plurality of first connecting pipes;
A control unit for controlling the opening of the opening adjustment valve;
A plurality of exhaust ports provided between a plurality of connection portions that respectively connect the exhaust ports to the exhaust manifold;
The control unit controls the first opening degree adjustment valve so that the exhaust gas discharged from the first cylinder is supplied to the supercharger through a connection unit corresponding to the second cylinder. A supercharged internal combustion engine that is controlled. The plurality of aperture portions are configured such that the aperture degree is variable,
The control unit has a throttle degree of a throttle unit provided in a range through which exhaust gas discharged from the first cylinder of the exhaust manifold passes among the plurality of throttle units compared to other throttle units. The supercharged internal combustion engine according to claim 1, wherein the supercharged internal combustion engine is largely controlled. A second connecting pipe connecting the plurality of connecting portions to the supercharger;
A second opening adjustment valve provided in the second connection pipe,
The control unit is configured to supply exhaust gas discharged from the first cylinder to the supercharger through a connection unit corresponding to the second cylinder, and to minimize the flow length of the exhaust gas. 2. The supercharged internal combustion engine according to claim 1, wherein the first opening degree adjusting valve and the second opening degree adjusting valve are controlled so as to become.   The supercharged internal combustion engine according to claim 3, wherein there are two or more of the second cylinders. A load detection unit for detecting the load of the internal combustion engine;
The supercharged internal combustion engine according to claim 2, wherein the control unit variably controls a throttle degree of the throttle unit based on a load detected by the load detection unit.

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