JP6482113B2 - Internal combustion engine - Google Patents

Description

The present invention relates to an internal combustion engine equipped with an exhaust turbocharger, and is particularly suitable for an automobile internal combustion engine.

  Internal combustion engines equipped with exhaust turbochargers are widely used. However, exhaust turbochargers have a range of use that works efficiently in relation to the flow rate and flow rate of exhaust gas. Exhaust turbochargers that can be supercharged up to the rotational speed have not yet appeared.

  Therefore, if the specification is adapted to the low rotation range where the amount of exhaust gas is small and the flow rate is slow, a phenomenon that exceeds the capacity occurs in the medium and high speed rotation region where the amount of exhaust gas is large and the flow rate is high, on the contrary. In the specifications adapted to the mid-high rotation range, the exhaust gas kinetic energy cannot be properly converted into the torque of the rotating shaft just by passing the exhaust gas through the turbine chamber in the low rotation range, and the desired supercharging cannot be performed (vehicles). In the case of use, the phenomenon that acceleration response at low speed is bad) occurs.

  In this regard, Patent Document 1 discloses that in a multi-cylinder internal combustion engine, one exhaust outlet corresponding to one cylinder is opened on one side of a cylinder head, and an independent exhaust passage is connected to each cylinder outlet. , Collecting these independent exhaust passages into one, connecting an exhaust turbocharger to this, connecting each exhaust outlet with a communication passage, and providing a switching valve at a branch portion between the communication passage and each independent passage Is disclosed.

JP 61-106319 A

  In Patent Document 1, the temperature of the exhaust gas is lowered by providing a communication passage, thereby reducing the thermal load of the exhaust turbocharger. However, since Patent Document 1 basically has one exhaust turbocharger (a twin turbo is disclosed in FIG. 7, a group of exhaust turbochargers is considered in relation to cylinders. There is no difference in that a large amount of exhaust gas passes through the exhaust turbocharger in the middle and high rotation range, and thus there is not only a limit on the reduction of heat load. It is difficult to say that high turbocharging performance can be secured in a wide range from low speed to high speed with one exhaust turbocharger.

  The present invention aims to improve such a current situation.

The internal combustion engine of the present invention is
"A cylinder block with multiple cylinders, said and cylinder head covering the respective cylinders are fixed, at each site corresponding to each cylinder of the cylinder head, a pair each exhaust port which is opened and closed by an exhaust valve Are each formed to open on one side of the cylinder head ,
A first exhaust manifold is connected to one group of the pair of exhaust ports, and a second exhaust manifold is connected to the other exhaust port group. ''
It is the basic composition.

Then, in the above Symbol basic configuration,
“A small exhaust turbocharger is connected to the first exhaust manifold, and a large exhaust turbocharger is connected to the second exhaust manifold,
Said pair of controlled by one or both of the exhaust gas flow valve means in the exhaust port, wherein by controlling the distribution of the exhaust gas to both the exhaust manifold, the small exhaust turbo at low revs, which is set in advance When exhaust gas flows into the charger and exceeds the low rotation range, the exhaust gas is controlled to flow through both the small exhaust turbocharger and the large exhaust turbocharger. "
It is the composition.

  In the present invention, a valve device such as a butterfly type or a shutter type can be arranged at the exhaust port as the valve means, but the exhaust valve itself is used as the valve means, and the exhaust valve is closed or half-opened in the exhaust stroke. Therefore, the exhaust gas can be changed to a state in which only one exhaust port flows or both exhaust ports flow.

When each pair of exhaust ports is fully open, exhaust gas flows through both the first exhaust manifold and the second exhaust manifold. By making each exhaust valve corresponding to the second exhaust manifold half open, it is possible to flow a smaller amount of exhaust gas into the second exhaust manifold than in the first exhaust manifold.

In the present invention, in the low speed range, the exhaust turbocharger connected to the first exhaust manifold is adopted for low speed, so that the supercharge response in the low speed range is improved. , Acceleration performance can be improved. That is, even if the exhaust gas emission amount is small, high supercharging performance in a low rotation range can be obtained by supplying exhaust gas to a small exhaust turbocharger intensively and at the highest possible speed.

On the other hand, in the middle and high rotation range, the exhaust gas flows through both the first exhaust manifold and the second exhaust manifold, so that the small exhaust turbocharger connected to the first exhaust manifold receives an excessive heat load or pumps. The exhaust gas can be appropriately discharged while preventing the loss from becoming large.

Since the small exhaust turbo supercharger that corresponds to the hand, an exhaust turbocharger operating at medium high speed range is a large amount of exhaust gases to work more efficient at low rotation range, from a low speed region High supercharging performance can be obtained over a wide range up to a high rotation range.

Although variable exhaust valve capable of changing the valve lift amount has been widely put into practical use, by the cam of the camshaft even in the exhaust stroke is set to avoid exposure to the pusher (lifter), the pair of exhaust valves Only one of them can be opened (or one can be kept closed). Therefore, if an exhaust valve with variable valve lift is used as the valve means, there is an advantage that the exhaust gas discharge mode can be reliably controlled without complicating the structure.

In the low rotation range, the amount of exhaust gas is small, generally low in temperature, and slow in flow rate. For this reason, as the distance to the exhaust turbocharger becomes longer, a decrease in kinetic energy due to shrinkage or the like due to a decrease in temperature appears more remarkably. On the other hand , when the first exhaust manifold is brought close to the cylinder head as in the embodiment, it leads to a small exhaust turbocharger without reducing the energy of the exhaust gas even in a low rotation range, thereby greatly reducing the energy loss. There is an advantage that can be suppressed.

It is a schematic diagram of the implementation forms.

  Next, an embodiment of the present invention will be described with reference to the drawings. This embodiment is applied to an internal combustion engine for automobiles. The internal combustion engine includes a cylinder block 2 having first to third three cylinders (cylinder bores) 1a to 1c, and a cylinder head 3 that is fixed to the upper surface of the cylinder block 2. The other longitudinal side surface 3a of the cylinder head 3 is provided. The first exhaust manifold 5 and the second exhaust manifold 6 are fixed to one longitudinal side surface 3 b of the cylinder head 3.

  A surge tank 7 is connected to a collecting portion of the intake manifold 4, and a throttle valve 8 is provided in the surge tank 7. An intake passage 10 starting from an air cleaner 9 is connected to the throttle valve 8.

  In the cylinder head 3, two exhaust ports of a first exhaust port 11 and a second exhaust port 12 are formed corresponding to each cylinder 1. Both the exhaust ports 11 and 12 are independent from each other, and their start ends open to the cylinder 1 and ends at the other longitudinal side surface 3 b of the cylinder head 3. The starting end of the first exhaust port 11 is opened and closed by the first exhaust valve 13, and the starting end of the second exhaust port 12 is opened and closed by the second exhaust valve 14.

The exhaust valves 13 and 14 are energized in the closing direction by springs, and the pusher with which the cam of the cam shaft abuts is moved up and down by hydraulic pressure or the like because the structure is well known and omitted from the drawings. When the pusher is fully lowered, the camshaft cam does not hit at all, and the exhaust valves 13 and 14 can be fully closed even in the exhaust stroke. The opening / closing amount can also be changed by changing the height of the contact portion of the rocker arm.

  The first exhaust manifold 5 and the second exhaust manifold 6 have three branch pipes 5a to 5c and 6a to 6c and collecting portions 5d and 6d, respectively. The first branch pipe 5a is connected to the second exhaust port 12 of the first cylinder 1a, the second branch pipe 5b is connected to the second exhaust port 12 of the second cylinder 1b, and the third branch pipe 5c is connected to the third cylinder. It is connected to the first exhaust port 11 of 1c.

  For the second exhaust manifold 5, the first branch pipe 6a is connected to the first exhaust port 11 of the first cylinder 1a, the second branch pipe 6b is connected to the first exhaust port 11 of the second cylinder 1b, and the third The branch pipe 6c is connected to the second exhaust port 12 of the third cylinder 1c. The branch pipes of the two exhaust manifolds 5 and 6 are crossed in a plan view, but buffering each other is avoided by bending the branch pipes 6a to 6c of the second exhaust manifold 6 downward (first exhaust manifold). 5 branch pipes 5a to 5c may be lowered, or both may be bent in the opposite direction.

  As can be understood from the drawing, the branch pipes 5 a to 5 c of the first exhaust manifold 5 are shorter than the branch pipes 6 a to 6 c of the second exhaust manifold 6.

Then, the turbine chamber 17 of the small exhaust turbocharger 15 is flange-connected to the collecting portion 5d of the first exhaust manifold 5, and the turbine chamber of the large exhaust turbocharger 16 is connected to the collecting portion 6d of the second exhaust manifold 6. 17 is flange-connected. Both the exhaust turbochargers 15 and 16 have a compressor chamber 18, and an exhaust turbine 19 disposed in the turbine chamber 17 and a compression impeller 20 disposed in the compressor chamber 18 are connected by a rotating shaft 21.

  The compressor chambers 18 of both the exhaust turbochargers 15 and 16 are connected by the intake passage 10 and the supercharging passage 22. Needless to say, the intake air flows into the compressor chamber 18 from the axial direction and is discharged in the circumferential direction. Exhaust gas flows into the turbine chamber 17 from the circumferential direction and exits in the axial direction.

The exhaust outlet passage 23 of the small exhaust turbocharger 15 is connected to the inlet passage 24 of the large exhaust turbocharger 16. Therefore, when the exhaust gas is discharged from all the exhaust ports 11 and 12 of all the cylinders 1a to 1c, the entire amount of the exhaust gas passes through the large exhaust turbocharger 16. In addition, the exhaust gas that has worked in the small exhaust turbocharger 15 will work again in the large exhaust turbocharger 16.

  Both the exhaust turbochargers 15, 16 are provided with a bypass passage 26 that leaks exhaust gas from the upstream side of the turbine chamber 17 to the exhaust outlets 23, 25, and a wastegate valve 27 is provided in the bypass passage 26.

In the above configuration, in the low speed region close to the Re idling region plasticizer, a first exhaust port 11 of the first cylinder 1a, a first exhaust port 11 of the second cylinder 1b, the second exhaust port 12 of the third cylinder 1c closes, the exhaust gas is Ru flows only in the first exhaust manifold 5. As a result, a small amount of exhaust gas can be flowed to the small exhaust turbocharger 15 as fast as possible, and high supercharging performance in a low rotation range can be ensured. Therefore, acceleration response at low speed can be enhanced.

When reaching a certain rotational range, all the exhaust ports 11 and 12 are opened. Then, both the exhaust turbochargers 15 and 16 are driven fully, and in this case as well, high supercharging performance can be obtained. By controlling the opening degree of the first exhaust valve 13 of the first cylinder 1a, the first exhaust valve 13 of the second cylinder 1b, and the second exhaust valve 14 of the third cylinder 1c according to the rotation range and torque. The supercharging rate of the large exhaust turbocharger 16 can be adjusted by adjusting the amount of exhaust gas flowing to the second exhaust manifold 6.

Optimal engine speed control can be realized by valve means comprising a combination of opening adjustment of these exhaust valves 13, 14 and control of the wastegate valve 27. In a state where the exhaust gas flows through the second exhaust manifold 6, the amount of exhaust gas flowing through the large-sized exhaust turbocharger 16 is greater than the amount of exhaust gas flowing through the small exhaust turbocharger 15, over the second exhaust turbo The feeder 16 is larger than the first exhaust turbocharger 15 .

Although the above embodiment is applied to a three-cylinder internal combustion engine, the present invention can be applied to a multi-cylinder internal combustion engine having other numbers of cylinders. The mode of connecting the first exhaust port and the second exhaust port to the two exhaust manifolds is not limited to the illustrated embodiment. It is also possible to connect each first exhaust port of each cylinder to one exhaust manifold and connect each second exhaust port of each cylinder to the second exhaust manifold.

  The present invention is actually applicable to an internal combustion engine. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1a-1c Cylinder 3 Cylinder head 4 Intake manifold 5 1st exhaust manifold 5a-5c Branch pipe 5d Collecting part 6 2nd exhaust manifold 6a-6c Branch pipe 6d Collecting part 11,12 Exhaust port 13,14 Exhaust valve as valve means 15 Small exhaust turbocharger 16 Large exhaust turbocharger 17 Turbine chamber 18 Compressor chamber 19 Exhaust turbine 20 Compression impeller
27 Wastegate valve constituting valve means

Claims (1)

A cylinder block with multiple cylinders, said and cylinder head covering the respective cylinders are fixed, at each site corresponding to each cylinder of the cylinder head, the exhaust ports of each pair which is opened and closed by an exhaust valve , Each formed to open on one side of the cylinder head ,
A first exhaust manifold is connected to one group of the pair of exhaust ports, and a second exhaust manifold is connected to the other exhaust port group,
A small exhaust turbocharger is connected to the first exhaust manifold, and a large exhaust turbocharger is connected to the second exhaust manifold;
Said pair of controlled by one or both of the exhaust gas flow valve means in the exhaust port, wherein by controlling the distribution of the exhaust gas to both the exhaust manifold, the small exhaust turbo at low revs, which is set in advance When exhaust gas flows to the feeder and exceeds the low rotation range, the exhaust gas is controlled to flow to both the small exhaust turbocharger and the large exhaust turbocharger.
Internal combustion engine.

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