JPS5919798Y2 - Cylinder block of multi-cylinder engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine cylinder block that includes a water jacket between four cylinder sections in which pistons reciprocate and an outer wall of the block.

In the above-mentioned engine, as a means for suppressing the membrane vibration of the outer wall of the block, which is the source of noise and vibration, in order to reduce noise and vibration of the engine, for example,
As disclosed in the publication, as shown in Figure 1, 4
It has been considered to increase the rigidity of the block outer wall B by forming outwardly protruding curved surface parts R1 to R8 on the block outer wall B corresponding to the cylinder parts C1 to C4, respectively.

However, the modes in the frequency range where engine noise and vibration become a problem are on the low-order side of the first to third orders.

In other words, a 4-cylinder engine (approximately 1
For 4-cylinder engines in the 000cc to 2000cc class, the frequency of the primary bending vibration of the cylinder block is 400cc.
Hz, its secondary frequency is around 800Hz, its tertiary frequency is around 1200Hz, and its primary frequency is around 40Hz.
Low frequency components around 0Hz vibrate the car body through the engine mount and become a factor in generating cabin noise (muffled sound), and the secondary and tertiary components are easily heard10
In the frequency range of around 00 Hz, vibrations of the cylinder block outer wall in this range produce radiated sound, which is one of the factors of noise outside the vehicle.

Therefore, if the conventional structure is set as described above, as shown by the dashed line in FIG. It has not been possible to sufficiently suppress the membrane vibration of the engine, and it has not been possible to effectively reduce the noise inside the vehicle caused by the vibration of the engine and the noise outside the vehicle caused by the engine noise (sound radiated from the cylinder block).

The present invention was made to solve the above-mentioned problems of the conventional structure, and by making the part of the block outer wall that becomes the antinode of vibration a curved surface, it is possible to sufficiently suppress the membrane vibration of the block outer wall. It is.

Embodiments of the present invention will be described below with reference to FIGS. 2 and 3.

2 and 3, 1a to 1d are four cylinder parts in which pistons (not shown) reciprocate;
is a water jacket provided between the cylinder parts 1a to 1d and the block outer wall 3.

The block outer wall 3 has curved surfaces 5a to 5f protruding outward at the intermediate portions between the adjacent cylinder portions 1a and lb, lb and 1c, and 1c and 1d, that is, the portions facing 4a, 4b, and 4C.

Therefore, with the above configuration, the block outer wall, which is the antinode of vibration in the frequency range where engine noise and vibration are a problem, is composed of a highly rigid curved surface, so it is possible to minimize the amplitude of the block outer wall. Therefore, it is possible to suppress membrane vibration on the outer wall of the block and reduce engine noise and vibration.

As described above, the present invention provides a cylinder block for a multi-cylinder engine that is equipped with a water jacket between four cylinder sections in which pistons reciprocate and an outer wall of the block. Since the outer wall of the block is formed with a curved surface portion that protrudes outward, membrane vibration of the outer wall of the block can be suppressed and engine noise and vibration can be sufficiently reduced.

[Brief explanation of the drawing]

1 is an explanatory cross-sectional view of a main part of a conventional cylinder block, FIG. 2 is a cross-sectional view of a main part showing an embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along the line III--III in FIG. 1a~1d...Cylinder B (4a~4C...
... middle), 3 ... block outer wall (5a ~
5f...Curved surface part).

Claims (1)

[Scope of utility model registration request] In a cylinder block of a multi-cylinder engine that has a water jacket between four cylinder parts in which pistons reciprocate inside and the outer wall of the block, a water jacket protrudes outward on the outer wall of the block opposite to the middle of the adjacent cylinder parts. A multi-cylinder engine cylinder block characterized by its curved shape.