The invention relates to a sound insulation structure of an internal combustion engine, and particularly to a sound insulation structure of an internal combustion engine for shutting off sounds generated by a fuel injection device.
A sound insulation structure of an internal combustion engine has been disclosed, e.g., in Japanese Patent Laying-Open No. 2000-179351 (Patent Reference 1).
The patent reference 1 has disclosed a structure in which a sound insulation cover is arranged around a direct-injection fuel infection valve located outside an engine body.
In a V-type engine, a fuel injection device is arranged in a narrow region between right and left banks, and prior arts have suffered from a problem that a sound insulation cover cannot be arranged in such a narrow region without difficulty.
Accordingly, the invention has been made for overcoming the above problem, and an object of the invention is to provide a sound insulation structure of an internal combustion engine that can suppress propagation of a sound generated by an engine body into an interior of a vehicle.
A sound insulation structure of an internal combustion engine according to the invention includes a cylinder block having left and right banks; a plurality of first intake pipes supplying a gas to the right bank; a plurality of second intake pipes supplying the gas to the left bank and intersecting the first intake pipes; a fuel injection device arranged in a surrounded space surrounded by the right and left banks and the first and second intake pipes; and a sound insulation member arranged in the surrounded space between the fuel injection device and an intersection region containing intersecting portions of the first and second intake pipes, being in contact with both the first and second intake pipes and extending in a direction of alignment of the plurality of first and second intake pipes.
According to the sound insulation structure of the internal combustion engine having the above structure, the sound insulation member is arranged in a surrounded region surrounded by the right and left banks and the first and second intake pipes, and the sound insulation member is in contact with both the first and second intake pipes, and extends in the direction of alignment of the plurality of first and second intake pipes. Therefore, the sound insulation member can absorb a sound generated by a fuel supply device arranged in the surrounded space.
Preferably, the sound insulation member is arranged between the plurality of first and second intake pipes. This structure can prevent leakage of the sound through a space between the plurality of first and second intake pipes, and can achieve higher sound insulation performance.
More preferably, the sound insulation member is arranged integrally. Since no gap is present in the sound insulation member, this structure can increase the sound insulation performance.
Further preferably, a gap is formed between the intersection region and the sound insulation member. Since an air flows through this gap, this structure can lower a temperature of the sound insulation member adjoining the gap, and can lower a temperature of the surrounded space. Consequently, the temperature of the fuel injection device arranged in the surrounded space can be lowered to prevent vaporization of the fuel in the fuel injection device.
Preferably, the sound insulation structure of the internal combustion engine further includes a cylinder head arranged on the right and left banks, and a gasket arranged between the cylinder head and the first and second intake pipes, and the gasket is integral with the sound insulation member. This structure can suppress transmission of a heat from the cylinder head to the first and second intake pipes. Therefore, it is possible to suppress increase in temperature of the surrounded space, and therefore to suppress the vaporization of fuel in the fuel injection device arranged in the surrounded space.
More preferably, the sound insulation member is formed of urethane foam. Since the urethane foam has a good sound insulation property and is light and flexible, it can be worked or processed easily.
Preferably, the sound insulation member is arranged in contact with the fuel injection device. In this structure, the sound insulation member in contact with the fuel injection device can absorb more reliably the sound generated by the fuel injection device.
Preferably, the sound insulation member is engaged between the plurality of first and second intake pipes. The first and second intake pipes can be attached to another member such as a cylinder head while holding the engaged sound insulation member between the first and second intake pipes, and this structure can improves an assembly property.
The invention can provide the sound insulation structure of the internal combustion engine having an improved sound insulation performance.
Embodiments of the invention will now be described with reference to the drawings. The same or corresponding portions in the following embodiments bear the same reference numbers, and description thereof is not repeated.
Engine 100 has a cylinder block 101, in which a piston 110 is arranged. Piston 110 is connected to a crankshaft by a connecting rod.
Cylinder block 101 has right and left banks 1011 and 1012, which intersect together with a predetermined angle therebetween. The angle between right and left banks 1011 and 1012 is merely required to be larger than 0 degrees and smaller than 180 degrees. Although this embodiment relates to the V-type engine, this is not restrictive, and the invention may be applied to a W-type engine and others that have a right bank(s) forming an angle with respect to a left bank(s).
A right bank cylinder head 121 is arranged on right bank 1011, and a left bank cylinder head 122 is arranged on left bank 1012. Right and left bank cylinder heads 121 and 122 form a cylinder head 120. Spark plugs 141 and 142 are arranged in cylinder head 120. An intake valve 181 and an exhaust valve 182 are arranged on the opposite sides of the spark plug for controlling flow of an air-fuel mixture into a combustion chamber and discharge of an exhaust gas from the combustion chamber. Intake and exhaust valves 181 and 182 are driven by rocker arms 165, respectively.
A water bypass pipe 150 is arranged between right and left banks 1011 and 1012.
In-cylinder injection injector 11 is arranged in right bank cylinder head 121, and in-cylinder injection injector 12 is arranged in left bank cylinder head 122. In-cylinder injection injectors 11 and 12 are fuel injection devices for directly injecting the fuel into the combustion chambers, respectively. In-cylinder injection injectors 11 and 12 that are the in-cylinder fuel injection devices are arranged in a region surrounded by right and left banks 1011 and 1012.
Intake manifold 20 is arranged above right and left bank cylinder heads 121 and 122. Intake manifold 20 is made of metal, and port injection injectors 13 and 14 (i.e., injectors for port injection) inject the fuel into an air passed through intake manifold 20. Port injection injectors 13 and 14 are attached to right and left cylinder heads 121 and 122, respectively. An intake variable valve timing mechanism 162 and an exhaust variable valve timing mechanism 163 controls timing of opening/closing operations of intake and exhaust valves 181 and 182, respectively.
Intake manifold 20 has a right bank intake pipe 21 and a left bank intake pipe 24, which are shaped to gather in an intersection region 28. A contact surface of intake manifold 20 with respect to cylinder heads 121 and 122 of the right and left banks form a junction surface 42, and a contact surface of intake manifold 20 with respect to surge tank unit 30 forms a junction surface 41. A region surrounded by right and left bank intake pipes 21 and 24 of intake manifold 20 forms a surrounded space 29, in which a sound insulation member 200 made of urethane foam is arranged. In this embodiment, sound insulation member 200 is in contact with intake manifold 20. However, this structure is not restrictive, and sound insulation member 200 may be in contact with right and left bank cylinder heads 121 and 122.
Instead of or in addition to the urethane form, sound insulation member 200 may be made of e.g., unwoven fabric of metal. Also, it may be made of an organic material such as engineering plastic.
Sound insulation structure 1 of the internal combustion engine according to the first embodiment includes V-type cylinder block 101 having right and left banks 1011 and 1012, right bank intake pipe 21 that is the first intake pipe and supplies the gas to right bank 1011, left bank intake pipe 24 that supplies the gas to left bank 1012 and intersects right bank intake pipe 21, in-cylinder injection injectors 11 and 12 that are the fuel injection devices and are arranged in surrounded space 29 surrounded by the right and left banks and the right and left intake pipes, and sound insulation member 200 located between in-cylinder injection injectors 11 and 12 and the intersection region where right and left bank intake pipes 21 and 24 intersect together, arranged in surrounded space 29, being in contact with right bank intake pipes 21, 22 and 23 and left bank intake pipes 24, 25 and 26, and extending in the direction of alignment of right bank intake pipes 21, 22 and 23 and left bank intake pipes 24, 25 and 26.
Projections 201, 202 and 203 of sound insulation member 200 are arranged between right bank intake pipes 21, 22 and 23 and left bank intake pipes 24, 25 and 26. Sound insulation member 200 has an integral form. The gap is formed between intersection region 28 and sound insulation member 200.
In-cylinder injection injectors 11 and 12 that are the high-pressure fuel injection valves generate operation sounds during the fuel injection. This operation sounds is propagated through an air to an interior of a vehicle, and therefore may affect silence of the vehicle. Members arranged around in-cylinder injection injectors 11 and 12 form a gap with respect to the intake pipe depending on the arrangement and configuration of intake manifold 20. Therefore, sound insulation member 200 is arranged for preventing the above operation sounds from being propagated through the gap thus formed to the outside of the vehicle room, and thereby the silence of the vehicle can be kept.
By arranging sound insulation member 200 between intersection region 28 and in-cylinder injection injectors 11 and 12, sound insulation member 200 can operate to cut off the sounds generated by in-cylinder injection injectors 11 and 12.
When sound insulation member 200 is arranged, a heat generating from cylinder head 120 may remain in surrounded space 29. Accordingly, the space formed between intersection region 28 and sound insulation member 200 can ensure an outer air passage to suppress rising of the temperature. Consequently, generation of a vapor inside in-cylinder injection injectors 11 and 12 can be suppressed. Although this embodiment relates to the structure having in-cylinder injection injectors 11 and 12 arranged in surrounded space 29, this is not restrictive, and port-injection injectors 13 and 14 may be arranged in surrounded space 29.
In sound insulation structure 1 of the internal combustion engine according to the third embodiment of the invention that has been described, since gasket 210 and sound insulation member 200 are integral with each other, heat conduction from cylinder head 120 to intake manifold 20 can be suppressed so that the rising of temperature of surrounded space 29 can be suppressed, and the vapor generation inside in-cylinder injection injectors 11 and 12 can be effectively suppressed. The urethane used as the sound insulation member achieves good sound insulation properties, light weight and flexibility, and allows easy working.
Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the scope of the present invention being interpreted by the terms of the appended claims.
The invention can be used in the field of the internal combustion engine mounted on the vehicle.
Number | Date | Country | Kind |
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2005-379119 | Dec 2005 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2006/326356 | 12/26/2006 | WO | 00 | 6/25/2008 |