JP2010059854A - Internal combustion engine - Google Patents

Abstract

An internal combustion engine capable of reliably varying the opening / closing timing of an intake valve or an exhaust valve to be varied by a variable valve operating device without impairing the mounting property on a vehicle body.
SOLUTION: First transmission means (40) for transmitting rotation of a crankshaft (10) to one of an intake camshaft (20) and an exhaust camshaft (30), and the above-described intake camshaft and exhaust camshaft. A variable valve gear (50) provided on either one and operating to vary the rotational phase of either the intake camshaft or the exhaust camshaft, and the rotation of either the intake camshaft or the exhaust camshaft. And a second transmission means (60) for transmitting the operation of the variable valve operating apparatus to one of the intake camshaft and the exhaust camshaft.
[Selection] Figure 1

Description

  The present invention relates to an internal combustion engine, and more particularly to a technique for optimizing the arrangement of variable valve gears.

  In recent years, the opening / closing timing of intake valves or exhaust valves has been varied for the purpose of improving the output performance of both low-medium-speed and low-load regions and high-speed and high-load regions of engines (internal combustion engines) mounted on vehicles. A variable valve operating device that can be used has been developed and put into practical use.

  As the variable valve operating device, the intake camshaft or the exhaust camshaft that rotates in accordance with the engine rotation and the cam sprocket, that is, the rotational phase angle between the camshaft and the crankshaft, is continuously changed within a predetermined range. A variable valve timing (variable valve timing; VVT) device capable of variably controlling the opening / closing timing of a valve or an exhaust valve is known.

Recently, for example, in a double overhead camshaft (DOHC) type engine, a driving pulley is provided at one end of the exhaust camshaft to transmit engine rotation from the crankshaft, and the exhaust camshaft is connected to the intake camshaft via a connecting gear. In this case, a variable valve timing device is provided on the one end side of the exhaust camshaft, and the exhaust camshaft is synchronized with the crankshaft. A technique in which only the shaft can vary the rotational phase is known (Patent Document 1).
Japanese Patent No. 2878252

  By the way, in the structure in which the variable valve timing device is provided on one end side of the exhaust camshaft or the intake camshaft, generally, the variable valve timing device must be structured so as to protrude outward. In some cases, the variable valve timing device interferes with other members (for example, an engine mount member) to hinder the mounting of the engine and the mountability of the engine on the vehicle body may be impaired.

For example, in Patent Document 1, the variable valve timing device is provided on one end side of the exhaust camshaft. However, if there is another member around the variable valve timing device, the variable valve timing device is referred to as the other member. The engine needs to be mounted on the vehicle body so as not to interfere with the engine, and the engine layout may not be optimized.
This problem is the same when the variable valve timing device is provided on one end side of the intake camshaft. In particular, in a vehicle in which the engine is placed horizontally in the vehicle width direction, one end of the intake camshaft is related to the torque roll shaft of the engine. Since the engine mount member is often disposed near the side, if the variable valve timing device is provided on one end side of the intake camshaft, the variable valve timing device and the engine mount member easily interfere with each other, which is remarkable.

  For this reason, on the other hand, the problem is that the variable valve timing device can be provided on one end side of the exhaust camshaft or the intake camshaft even though it is desired to vary the opening / closing timing of the exhaust valve or the intake valve. In other words, the opening / closing timing of the exhaust valve or the intake valve cannot be varied, which is not preferable.

  The present invention has been made to solve such problems, and the object of the present invention is to change the opening / closing timing of an intake valve or an exhaust valve that is desired to be varied without impairing the mountability to the vehicle body. An object of the present invention is to provide an internal combustion engine that can be reliably varied by an apparatus.

  In order to achieve the above object, an internal combustion engine according to claim 1 includes a crankshaft, an intake camshaft having a cam for opening and closing an intake valve, an exhaust camshaft having a cam for opening and closing an exhaust valve, A first transmission means for transmitting rotation of a crankshaft to one of the intake camshaft and the exhaust camshaft; and one of the intake camshaft and the exhaust camshaft; A variable valve operating device that operates to vary the rotational phase of the other of the exhaust camshaft, and the operation of the variable valve operating device along with the rotation of either the intake camshaft or the exhaust camshaft. A second transmission means for transmitting to the other of the camshaft and the exhaust camshaft. The features.

In the internal combustion engine according to claim 2, in claim 1, the first transmission means is an endless chain or belt, and is at least one of the crankshaft, the intake camshaft, and the exhaust camshaft. The rotation of the crankshaft is transmitted to only one of the crankshafts.
Further, in the internal combustion engine of claim 3, in claim 2, the endless chain or belt is stretched over both the crankshaft, the intake camshaft and the exhaust camshaft, and the intake cam The other of the shaft and the exhaust camshaft has a non-transmission means that does not transmit the rotation of the crankshaft to the other through the endless chain or belt.

The internal combustion engine according to claim 4 is characterized in that, in claim 3, the non-transmission means is a play car.
Further, in the internal combustion engine according to claim 5, in any one of claims 1 to 4, one of the intake camshaft and the exhaust camshaft is the exhaust camshaft, and the other is the intake cam. It is a shaft.

  According to the internal combustion engine of claim 1, the rotation of the crankshaft is transmitted to one of the intake camshaft and the exhaust camshaft by the first transmission means, and the rotation of either one is taken by the second transmission means. In this case, the operation of the variable valve mechanism provided on either the intake camshaft or the exhaust camshaft is rotated by the second transmission means. At the same time, it is transmitted to either the intake camshaft or the exhaust camshaft, and the rotational phase of either one is appropriately variably operated.

  Therefore, for example, even if one of the intake camshaft and the exhaust camshaft has a restriction on installation space related to the mountability to the vehicle body, the intake camshaft cannot be provided. By providing the variable valve device for the other on either one of the exhaust camshaft and the exhaust camshaft, the second transmission means transmits the operation of the variable valve device to the other of the intake camshaft and the exhaust camshaft. can do.

Thereby, the opening / closing timing of the intake valve or the exhaust valve to be varied can be reliably varied by the variable valve operating device without impairing the mounting property to the vehicle body.
According to the internal combustion engine of the second aspect, the first transmission means is an endless chain or belt, and spans the crankshaft and at least one of the intake camshaft and the exhaust camshaft to rotate the crankshaft. Is transmitted to only one of them, and in a general conventional configuration in which an endless chain or belt is used as the first transmission means, it can be varied without impairing mounting on the vehicle body. The opening / closing timing of the intake valve or exhaust valve can be reliably varied by the variable valve operating device.

  According to the internal combustion engine of the third aspect, the endless chain or belt is stretched over both the crankshaft, the intake camshaft, and the exhaust camshaft. Since there is a non-transmission means that does not transmit the rotation of the crankshaft to the other through an endless chain or belt, for example, in the central part of the surface of the internal combustion engine on the side where the chain or belt is passed In many cases, various members such as an auxiliary machine of an internal combustion engine are disposed, but the rotation of the crankshaft is not directly transmitted to one of the intake camshaft and the exhaust camshaft by non-transmission means, It is possible to effectively use it as an installation space for auxiliary machines, etc. by preventing the chain or belt from passing through the center part. That.

Thereby, the opening / closing timing of the intake valve or the exhaust valve that is desired to be varied can be reliably varied by the variable valve operating device without further impairing the mountability to the vehicle body.
According to the internal combustion engine of the fourth aspect, the non-transmission means can be easily configured with an idler wheel (idling pulley, idling sprocket, idling gear, etc.).
According to the internal combustion engine of claim 5, since either one of the intake camshaft and the exhaust camshaft is an exhaust camshaft and the other is an intake camshaft, the exhaust camshaft is provided with a variable valve gear. Then, the operation of the variable valve operating device is transmitted to the intake camshaft by the second transmission means, and the rotational phase of the intake camshaft is appropriately variably operated.

  Therefore, for example, in a vehicle in which the internal combustion engine is placed horizontally in the vehicle width direction, an engine mount member is often disposed near one end side of the intake camshaft because of the relationship with the torque roll shaft of the internal combustion engine. If it is provided at one end of the intake camshaft, the variable valve operating device and the engine mount member easily interfere with each other. Even in such a case, the variable valve operating device for the intake camshaft is provided on the exhaust camshaft side. The operation of the variable valve device can be transmitted to the intake camshaft by the second transmission means, and the rotation phase of the intake camshaft is variably operated while avoiding interference between the variable valve device and the engine mount member. can do.

  Thereby, especially when it is desired to vary the opening / closing timing of the intake valve, the opening / closing timing of the intake valve can be reliably varied by the variable valve operating device without impairing the mountability to the vehicle body.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
First, the first embodiment will be described.
Referring to FIG. 1, there is schematically shown a front view of an internal combustion engine according to a first embodiment of the present invention mounted on a vehicle, and with reference to FIG. 2, a part of a top view of the internal combustion engine is shown. In the following, the first embodiment will be described with reference to FIGS.

An internal combustion engine (hereinafter referred to as an engine) 1 is, for example, a multi-point injection (MPI) double overhead camshaft (DOHC) type in-line four-cylinder gasoline engine, and is long in an engine room in front of the vehicle. The vehicle is mounted so that the direction is the vehicle width direction, that is, horizontally.
As shown in FIG. 1, the engine 1 is roughly configured such that a crankcase 4 is joined to a lower part of a cylinder block 2, a cylinder head 6 is placed on the upper part of the cylinder block 2, and a rocker is mounted on the cylinder head 6. A cover 8 is placed and configured.

  Between the cylinder block 2 and the crankcase 4, a crankshaft 10 extending in the longitudinal direction and converting the motion of the piston into a rotational motion is pivotally supported. The cylinder head 6 extends in parallel with the crankshaft 10 to open and close an exhaust camshaft 20 having a cam for opening and closing an exhaust valve (not shown) and an intake valve (not shown). An intake camshaft 30 having a cam is pivotally supported.

  A crank pulley 12 is coupled to one end of the illustrated crankshaft 10, and a driving exhaust cam pulley 22 for receiving a driving force from the crank pulley 12 is coupled to the exhaust camshaft 20. An endless timing belt (first transmission means) 40 is stretched between the pulley 12 and the driving exhaust cam pulley 22. As a result, when the engine 1 operates and the crankshaft 10 rotates, the rotation of the crankshaft 10 is transmitted to the driving exhaust cam pulley 22 via the timing belt 40, and the exhaust camshaft 20 rotates synchronously with the rotation of the crankshaft 10. To do.

Further, on the outside of the exhaust camshaft 20 for driving the exhaust camshaft 20, the rotation of the exhaust camshaft 20 is input, and the variable valve timing (variable variable) that can be output by changing the rotation phase within a predetermined range with respect to this input. A valve timing (VVT) device (hereinafter referred to as a VVT device) (variable valve operating device) 50 is connected.
Between the driving exhaust cam pulley 22 and the VVT device 50, an interlocking exhaust cam pulley 24 is disposed so as to be rotatably fitted to the exhaust camshaft 20, and the interlocking exhaust cam pulley 24 includes a VVT. The output shaft 52 of the device 50 is coupled.

That is, the VVT device 50 is configured to be able to transmit the rotation of the exhaust camshaft 20 to the interlocking exhaust cam pulley 24 while changing the phase.
As the VVT device 50, a vane type, a helical gear type, an electromagnetic motor type, and the like are known, but any of them can be applied here. The VVT device 50 of each of these methods is known, and detailed description of the structure is omitted here.

  On the other hand, an intake cam pulley 32 for receiving driving force from the interlocking exhaust cam pulley 24 is coupled to the intake camshaft 30. The interlocking exhaust cam pulley 24 and the intake cam pulley 32 are connected to an endless timing belt ( (Second transmission means) 60 is stretched over. As a result, when the interlocking exhaust cam pulley 24 rotates, the rotation of the interlocking exhaust cam pulley 24 is transmitted to the intake cam pulley 32 via the timing belt 60, and the intake camshaft 30 rotates in synchronization with the interlocking exhaust cam pulley 24.

  When the drive exhaust cam pulley 22, the interlocking exhaust cam pulley 24, the intake cam pulley 32, the timing belt 40, the VVT device 50, and the timing belt 60 are configured in this way, as described above, the VVT device 50 includes the exhaust camshaft. Since the rotation of the engine 20 can be transmitted to the interlocking exhaust cam pulley 24 by changing the phase, the exhaust camshaft 20 can be rotated synchronously with the crankshaft 10 as the engine 1 is operated. 30 can transmit the operation of the VVT device 50 together with the rotation of the exhaust camshaft 20.

That is, by configuring as described above, it is possible to rotate only the intake camshaft 30 with respect to the rotation of the crankshaft 10 by the VVT device 50 while providing the VVT device 50 on the exhaust camshaft 20 side. Only the opening / closing timing of the intake valve can be variably operated.
Thus, for example, referring to FIG. 2, the engine mount member 70 is also shown. Normally, when the engine 1 is placed horizontally in the vehicle width direction, the intake cam is thus taken into account from the relationship with the torque roll shaft of the engine 1. In many cases, the engine mount member 70 is disposed in the vicinity of one end side of the shaft 20, and therefore, there is a tendency to restrict the installation space on one end side of the intake camshaft 20. Even when it is desired to vary the opening / closing timing, the opening / closing timing of the intake valve can be varied while avoiding interference between the VVT device 50 and the engine mount member 70 by providing the VVT device 50 on the exhaust camshaft 20 side. Can do.

As described above, according to the internal combustion engine according to the first embodiment of the present invention, the VVT device 50 can reliably vary the opening / closing timing of the intake valve to be varied without impairing the mountability of the engine 1 on the vehicle body. Is possible.
In addition, as shown in FIGS. 1 and 2, the horizontal engine 1 is generally mounted on the vehicle body with the intake system on the front side and the exhaust system on the rear side. By providing on the side of the exhaust camshaft 20 on the side, there is a margin in the layout of the engine 1 in the engine room. As a result, for example, in the event of a vehicle collision, it is possible to secure a sufficient amount of collapse of the vehicle body and improve the safety of the passenger.

  Further, the horizontally installed engine 1 is generally installed in a posture inclined rearward as shown in FIG. 1 with the intake system on the front side and the exhaust system on the rear side. In this case, the VVT device 50 is installed on the rear intake side. By providing on the camshaft 20 side, the distance (gap) between the engine 1 and the hood 80 that closes the engine room can be made relatively large. Thereby, it is possible to strengthen pedestrian protection.

Next, a second embodiment will be described.
Referring to FIG. 3, there is schematically shown a front view of an internal combustion engine according to a second embodiment of the present invention mounted on a vehicle. Referring to FIG. 4, a part of a top view of the internal combustion engine is shown. The second embodiment will be described below with reference to FIGS.
In the second embodiment, in place of the timing belt 40, an endless timing belt 40 'is stretched over the intake camshaft 30 as well as the crank pulley 12 and the drive exhaust cam pulley 22. In the following, only the differences from the first embodiment will be described.

As shown in FIG. 4, the intake camshaft 30 is coupled to an intake cam pulley 32 for receiving a driving force from the interlocking exhaust cam pulley 24, and is positioned inside the intake cam pulley 32 and is an idle pulley (non-transmission means). , A play wheel) 34 is externally fitted so as to freely rotate.
That is, referring to FIG. 5, a top view of the internal combustion engine with the timing belt 40 ′ removed in FIG. 4 is shown. As shown in FIG. 5, the idle pulley 34 is connected to the driving exhaust cam pulley 22. The intake camshaft 30 is externally fitted in a corresponding position.

A timing belt 40 ′ is wound around the crank pulley 12, the driving exhaust cam pulley 22, and the idling pulley 34.
When the timing belt 40 ′ is stretched in this way, when the engine 1 is operated and the crankshaft 10 rotates, the idle pulley 34 idles around the intake camshaft 30, so that the rotation of the crankshaft 10 is directly performed. As in the case of the first embodiment, the rotation of the crankshaft 10 is transmitted only to the driving exhaust cam pulley 22 via the timing belt 40 ′, and the exhaust camshaft 20 is not transmitted to the intake camshaft 30. The crankshaft 10 rotates in synchronization with the rotation.

The intake camshaft 30 rotates in synchronism with the interlocking exhaust cam pulley 24 in exactly the same manner as in the first embodiment. That is, also in the second embodiment, only the intake camshaft 30 can be rotated with respect to the rotation of the crankshaft 10 by the VVT device 50, and only the opening / closing timing of the intake valve can be variably operated. .
Since the timing belt 40 'is stretched in this way, as is clear from FIG. 3, the range surrounded by the timing belt 40' is wider than that of the timing belt 40 of the first embodiment. Thus, it is possible to form a wide area where the timing belt 40 ′ does not pass on the surface on which the timing belt 40 ′ of the engine 1 is routed, that is, the central portion of the front surface of the engine 1. As a result, for example, an auxiliary machine 90 as shown in FIG. 3 is often provided in the central portion of the engine 1, but the auxiliary machine 90 and other members are arranged without interference with the timing belt 40 ′. be able to.

  As described above, according to the second embodiment, the timing belt 40 ′ is looped over the idle pulley 34 fitted to the intake camshaft 30 together with the crank pulley 12 and the drive exhaust cam pulley 22 to rotate the crankshaft 10. Is not transmitted directly to the intake camshaft 30, and the central portion of the front surface of the engine 1 is prevented from passing through the timing belt 40 ', so that it can be effectively used as an installation space for the auxiliary machine 90 and the like.

Thus, the opening / closing timing of the intake valve to be varied can be reliably varied by the VVT device 50 without further impairing the mountability of the engine 1 on the vehicle body.
Here, since the idle pulley 34 is used as the non-transmission means, the non-transmission means can be easily configured by the idle pulley 34.

Although the description of the internal combustion engine according to the present invention has been completed above, the present invention is not limited to the above embodiment.
For example, in the above-described embodiment, the case where the VVT device 50 is provided on the exhaust camshaft 20 side and the rotational phase of the intake camshaft 30 is varied has been described. However, depending on the situation, the intake camshaft 30 side may be reversed. A VVT device 50 may be provided to vary the rotational phase of the exhaust camshaft 20.

  In the above-described embodiment, the pulleys 12, 22, 24, 32, and 34 are connected by the timing belts 40 and 60. However, the pulleys 12, 22, 24, 32, and 34 are replaced with sprockets, and the timing is changed. The belts 40 and 60 may be replaced with timing chains. Furthermore, the pulleys 12, 22, 24, 32, and 34 may be replaced with gears, and a plurality of gears may be combined instead of the timing belt or the timing chain.

1 is a front view of an internal combustion engine according to a first embodiment of the present invention mounted on a vehicle. It is a figure which shows schematically a part of top view of the internal combustion engine which concerns on 1st Example. It is a front view of the internal combustion engine which concerns on 2nd Example of this invention mounted in the vehicle. It is a figure which shows schematically a part of top view of the internal combustion engine which concerns on 2nd Example. It is a top view of the internal combustion engine which concerns on 2nd Example of the state which removed the timing belt.

Explanation of symbols

1 engine (internal combustion engine)
DESCRIPTION OF SYMBOLS 10 Crankshaft 12 Crank pulley 20 Exhaust camshaft 22 Drive exhaust cam pulley 24 Interlocking exhaust cam pulley 30 Intake camshaft 32 Intake cam pulley 34 Idle pulley (non-transmission means)
40 Timing belt (first transmission means)
50 VVT device (variable valve operating device)
60 Timing belt (second transmission means)

Claims (5)

A crankshaft,
An intake camshaft having a cam for opening and closing the intake valve;
An exhaust camshaft having a cam for opening and closing the exhaust valve;
First transmission means for transmitting rotation of the crankshaft to either the intake camshaft or the exhaust camshaft;
A variable valve gear that is provided on one of the intake camshaft and the exhaust camshaft and that operates to vary the rotational phase of the other of the intake camshaft and the exhaust camshaft;
Second transmission means for transmitting the operation of the variable valve gear to the other one of the intake camshaft and the exhaust camshaft together with the rotation of either the intake camshaft or the exhaust camshaft;
An internal combustion engine comprising:   The first transmission means is an endless chain or belt, and spans between the crankshaft and at least one of the intake camshaft and the exhaust camshaft, and rotates the crankshaft. 2. The internal combustion engine according to claim 1, wherein transmission is made only to one of the two. The endless chain or belt is stretched over both the crankshaft, the intake camshaft and the exhaust camshaft;
The other of the intake camshaft and the exhaust camshaft has a non-transmission means that does not transmit the rotation of the crankshaft to the other through the endless chain or belt. The internal combustion engine according to claim 2.   The internal combustion engine according to claim 3, wherein the non-transmission means is a play car.   5. The internal combustion engine according to claim 1, wherein one of the intake camshaft and the exhaust camshaft is the exhaust camshaft, and the other is the intake camshaft. 6. organ.

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