JP2007009774A - Internal combustion engine equipped with variable compression ratio mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease members moving in accompaniment to the change in the compression ratio in an internal combustion engine equipped with a variable compression ratio mechanism. <P>SOLUTION: The internal combustion engine 1 equipped with the variable compression ratio mechanism 10 to change the compression ratio by changing the relative distance between a crankcase 5 and movable parts 3 and 4 is provided with a fixer 8 connected to the movable parts 3 and 4, and fixed to a vehicle side 11, and a connector 7 to connect the fixer 8 and the movable parts 3 and 4, changeable accompanied by the change in the compression ratio of the internal combustion engine 1. The mass of a surge tank 8 and members, etc., disposed upstream of the surge tank 8, can be removed from the mass of the member moving in changing the compression ratio. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an internal combustion engine capable of changing a compression ratio.

  The compression ratio can be changed by changing the relative distance between the cylinder block and the piston at the top dead center, and the thermal efficiency of the internal combustion engine can be improved.

  By the way, when the cylinder block is moved in the piston movement direction in order to change the relative distance between the cylinder block and the piston, a cylinder head, an intake manifold, a surge tank, an exhaust manifold, etc. connected to the cylinder block are also included. Will move together.

Here, in an internal combustion engine that does not include a variable compression ratio mechanism, since the cylinder head does not move, the intake manifold can be supported by a support bracket fixed to the vehicle body or the internal combustion engine body (see, for example, Patent Document 1). ).
Japanese Utility Model Publication No. 7-38658 Japanese Utility Model Publication No. 7-35757 JP-A-3-281975 JP 2003-206871 A

  However, in an internal combustion engine having a variable compression ratio mechanism, the intake manifold, surge tank, exhaust manifold, and the like are also moved together with the cylinder head. Therefore, the intake manifold, surge tank, exhaust manifold, etc. It is difficult to fix to

  For this reason, when the intake manifold or the like is fixed to the cylinder block side, the mass of the member that moves when the compression ratio is changed increases accordingly, and it takes time to change the compression ratio, and a large force is required to move the cylinder block. It becomes. Furthermore, when the intake manifold or the like is fixed to the cylinder head, there is a possibility that the support bracket fixing method is limited or the support bracket cannot be attached.

  In an internal combustion engine having a variable compression ratio mechanism that changes the compression ratio by changing the relative distance between the cylinder head and the cylinder block and the piston at the top dead center, the cylinder head and the cylinder block move. The cylinder head and cylinder block cannot be supported by an engine mount or the like. Therefore, the cylinder head and the cylinder block are likely to vibrate.

  The present invention has been made in view of the various problems as described above, and an object thereof is to reduce the number of members that move as the compression ratio changes in an internal combustion engine having a variable compression ratio mechanism. .

In order to achieve the above object, an internal combustion engine provided with a variable compression ratio mechanism according to the present invention is characterized by the following. That is,
A crankcase,
A movable part that moves relative to the crankcase;
In the internal combustion engine having a variable compression ratio mechanism that changes the compression ratio by changing the gap volume by changing the relative distance between the crankcase and the movable part,
A fixed part connected to the movable part and fixed to the vehicle body;
A connecting part that connects the fixed part and the movable part and is deformable in accordance with a change in the compression ratio of the internal combustion engine;
It is characterized by providing.

  As described above, when the fixing portion is fixed to the vehicle body side, the fixing portion does not move even if the compression ratio is changed. The connection between the fixed part and the movable part is ensured by the connection part. Thereby, since the mass of the fixed part can be reduced from the mass of the movable part that moves when the compression ratio is changed, the compression ratio can be quickly changed.

  The fixing portion may be a surge tank, an intake manifold, or an exhaust manifold. Further, for example, a surge tank may be attached to the movable part, and the throttle body may be fixed to the vehicle body side.

  In the present invention, the connecting portion may be a free pipe.

  As the universal pipe, for example, a pipe made of an elastic material or a pipe having a bellows structure can be used. If the positional relationship between the movable portion and the fixed portion changes when the compression ratio is changed, the universal pipe expands and / or bends. Accordingly, it is possible to achieve both movement of the movable part and fixation of the fixed part to the vehicle body while securing the connection between the fixed part and the movable part. Moreover, the vibration of the movable part can be attenuated by the free pipe by connecting the fixed part and the movable part by the free pipe.

  According to the internal combustion engine including the variable compression ratio mechanism according to the present invention, it is possible to reduce the number of members that move as the compression ratio changes. Thereby, the compression ratio can be changed quickly, and the force required for changing the compression ratio can be reduced.

  Specific embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a variable compression ratio internal combustion engine (hereinafter simply referred to as “internal combustion engine”) 1 in which the compression ratio is variable. In this embodiment, in order to display the internal combustion engine 1 in a concise manner, some components are not shown.

  The internal combustion engine 1 is a gasoline engine having four cylinders 2.

  The internal combustion engine 1 includes a cylinder head 3, a cylinder block 4, and a crankcase 5. Each cylinder 2 is provided with a piston 6.

  In the internal combustion engine 1 according to the present embodiment, for example, as described in Japanese Patent Application Laid-Open No. 2003-206871, the cylinder block 4 is arranged in the cylinder axial direction (hereinafter also referred to as the vertical direction) with respect to the crankcase 5. A variable eccentricity ratio mechanism 10 is provided which is attached so as to be able to move forward and backward, and is provided with a double eccentric shaft at the connecting portion thereof, and the cylinder block 4 is driven to move forward and backward by swinging and rotating the double eccentric shaft.

  According to the variable compression ratio mechanism 10, the cylinder head 3 together with the cylinder block 4 is moved relative to the crankcase 5 in the axial direction of the cylinder 2. As a result, the volume (gap volume) of the combustion chamber constituted by the cylinder block 4, the cylinder head 3 and the piston 6 is changed. As a result, the compression ratio of the internal combustion engine 1 is variably controlled. For example, when the cylinder block 4 is relatively moved away from the crankcase 5, the combustion chamber volume increases and the compression ratio decreases.

  An intake branch pipe 7 is connected to the internal combustion engine 1, and one end of each branch pipe of the intake branch pipe 7 communicates with a combustion chamber of each cylinder 2 via an intake port 30 formed in the cylinder head 3. ing. The other end of each branch pipe of the intake branch pipe 7 is connected to the surge tank 8.

  A throttle body 9 is provided upstream of the surge tank 8. The throttle body 9 is provided with a throttle valve 90 that adjusts the flow rate of intake air flowing into the surge tank 8.

  In this embodiment, the crankcase 5 is fixed to the vehicle body 11 via the engine mount 51, and the surge tank 8 is fixed to the vehicle body 11. A universal pipe is used for the intake branch pipe 7 that connects the cylinder head 3 and the surge tank 8. For this universal pipe, for example, an elastic body such as rubber that can be expanded and contracted and bent can be used. Moreover, what made resin or a metal bellows structure can also be used as a free pipe. Since the distance that the cylinder head 3 etc. moves when the compression ratio is changed is several millimeters, it is sufficient that the free pipe is deformed by this distance.

  With this configuration, when the cylinder head 3 moves in the vertical direction when the compression ratio is changed, the intake branch pipe 7 expands and contracts and further bends. Therefore, even if the surge tank 8 is fixed to the vehicle body 11, the intake branch pipe 7 does not come off from the cylinder head 3 and the surge tank 8. Thereby, both movement of the cylinder head 3 and fixation to the vehicle body 11 of the surge tank 8 can be made compatible.

  Further, the vibration generated in the cylinder head 3 and the cylinder block 4 is attenuated by the universal pipe.

  As described above, according to the present embodiment, since it is not necessary to fix the surge tank 8 having a large mass to the cylinder head 3 or the cylinder block 4, the cylinder head 3 or the cylinder block 4 is quickly moved up and down. It becomes possible. That is, the compression ratio can be changed quickly. Furthermore, the compression ratio can be changed with less force. Further, the intake branch pipe 7 can suppress the vibration of the internal combustion engine 1.

  In this embodiment, all members of the intake system including the throttle body 9 and the surge tank 8 are fixed to the vehicle body 11. Instead, the surge tank 8 is fixed to the cylinder head 3 or the cylinder block 4. The throttle body 9 may be fixed to the vehicle body 11. Further, the surge tank 8 and the throttle body 9 may be fixed to the cylinder head 3 or the cylinder block 4, and a turbocharger, an air cleaner, or the like upstream thereof may be fixed to the vehicle body 11. In these cases, the member fixed to the cylinder head 3 or the cylinder block 4 side and the member fixed to the vehicle body 11 side are connected using the universal pipe.

  Similarly to the intake system member, the exhaust system member may be fixed to the vehicle body side. For example, the exhaust manifold may be fixed to the vehicle body side, and the cylinder head 3 and the exhaust manifold may be connected by an exhaust pipe having a bellows structure. Further, the catalyst or the particulate filter may be fixed to the vehicle body side.

  Here, FIG. 2 is a diagram showing a schematic configuration of the internal combustion engine when the surge tank 8 is fixed to the cylinder head 3 and the throttle body 9 is fixed to the vehicle body 11. The cylinder head 3 and the surge tank 8 are connected by an intake branch pipe 70. The intake branch pipe 70 is formed integrally with the surge tank 8. Further, the throttle body 9 is fixed to the vehicle body 11, and the surge tank 8 and the throttle body 9 are connected via an intake pipe 71. As the intake pipe 71, the universal pipe is used.

  In the internal combustion engine 1 configured as described above, when the cylinder head 3 moves when the compression ratio is changed, the surge tank 8 and the intake branch pipe 70 also move in the same direction. At this time, the intake pipe 71 expands and contracts and bends. Thereby, both movement of the cylinder head 3 and fixation of the throttle body 9 to the vehicle body 11 can be achieved.

  Even if it does in this way, the mass of a moving part can be reduced and the vibration of the internal combustion engine 1 can be suppressed.

It is a figure showing the schematic structure of the variable compression ratio internal combustion engine which makes a compression ratio variable. It is a figure showing the schematic structure of an internal combustion engine when a surge tank is fixed to a cylinder head and a throttle body is fixed to a vehicle body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Cylinder 3 Cylinder head 4 Cylinder block 5 Crankcase 6 Piston 7 Intake branch pipe 8 Surge tank 9 Throttle body 10 Variable compression ratio mechanism 11 Car body 30 Intake port 51 Engine mount 70 Intake branch pipe 71 Intake pipe 90 Throttle valve

Claims (2)

A crankcase,
A movable part that moves relative to the crankcase;
In the internal combustion engine having a variable compression ratio mechanism that changes the compression ratio by changing the gap volume by changing the relative distance between the crankcase and the movable part,
A fixed part connected to the movable part and fixed to the vehicle body;
A connecting part that connects the fixed part and the movable part and is deformable in accordance with a change in the compression ratio of the internal combustion engine;
An internal combustion engine provided with a variable compression ratio mechanism.   The internal combustion engine having a variable compression ratio mechanism according to claim 1, wherein the connecting portion is a universal pipe.

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