JPS5937247A - Cylinder block for automotive engine - Google Patents

Abstract

PURPOSE:To increase the rigidity of a cylinder block, by forming both of the outer wall of water jacket and skirt part of the cylinder block substantially in an arcuate form projected outward and contiguous with each other in the principal section of the cylinder block taken along a line near the center of a cylinder bore. CONSTITUTION:The outer wall 14 surrounding a cylinder 12 and defining water jacket 13 is shaped substantially in an arcuate form projected outward so that the cross sectional area of the outer wall 14 is reduced gradually toward the top in its principal section taken along a line near the center of a cylinder bore. At the lower end of the outer wall 14, skirt part 15 also shaped substantially in an arcuate form projected outward is formed continuously with the outer wall 14 in the manner of surrounding the envelop X of the big end of a connecting rod and constituting the same curved surface as the outer wall 14 defining the water jacket.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in cylinder 10 for a water-cooled automobile engine.

FIG. 1 shows a half-Nucato-shaped cylinder block in a conventional automatic stealth engine. In this cylinder block, the outer wall V of the water jacket 3 surrounding the cylinder 82Y is approximately parallel to the center line of the cylinder portion λ. Yes, on the other hand, there is a skirt part S that forms part of the crank chamber.
The outer wall V and the skirt part j have an approximately arc-like shape along the envelope line of the connecting end.
They are connected by an arcuate portion t with r.

However, in such a conventional configuration, the joint rigidity at the arcuate portion t between the water jacket outer wall μ and the skirt portion S is not sufficient, and only the skirt portion S is greatly expanded in an arcuate shape. 1. Both strengths can be effectively utilized for pipe pressure, and the rigidity of the cylinder block/in particular, the rigidity against torsion as shown in Figure 2 or the left/right bending deformation mode as shown in Figure 3. Therefore, the cylinder block is likely to vibrate due to the vibration input from the crankshaft caused by the combustion impact force. In the skirt part 3, due to its structure, these vibrations become opening/closing vibrations with the circular arc part as a fulcrum as shown in Figure 1, which radiates significant noise to the outside and also damages the oil pan, which becomes a secondary sound source. Y will also be photographed. Similarly, the water jacket outer wall l also generates membrane vibration Y, which makes it easier to generate sound.
lKH2 which causes problems as engine noise from these parts.
The noise in the front and back was at an extremely high level.

Incidentally, such vibration noise becomes particularly significant when the cylinder block is made of light alloy to reduce weight.

This invention was made in view of such conventional problems, and its purpose is to solve the problem.

The purpose is to improve the rigidity of the lock and to reduce engine noise emitted from the skirt portion, water jacket outer wall, etc.

That is, the cylinder block for an automobile engine according to the present invention has a substantially outwardly convex portion in the main cross section along the vicinity of the center of the cylinder bore, such as the outer wall of the water jacket surrounding the cylinder portion Y and the skirt portion forming the crank chamber. It is characterized by being formed continuously in an arc shape.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings. Fig. 4 shows the top view of the cylinder block/l according to the present invention, and Fig. 5 shows the side view of the cylinder block/l. /J? In the main cross section along the vicinity of the center of the cylinder bore, the defining water jacket outer wall /4' has a substantially circular arc shape that gradually narrows toward the top and convex outward. On the forming groove and at the lower end of this outer wall/da, there is a substantially arc-shaped skirt part/3 which similarly convexes outward so as to enclose the envelope xy of the large end of the connecting gland, which is the same as the water jacket/q. It is continuously formed to have a curved surface. The lower end of the water jacket outer wall/da and the upper end of the skirt portion 13. The lower deck/6 connected to the cylinder portion l:l is located at the position of the lowest piston ring when the piston (not shown) is at the bottom dead center. A rib /g is provided so as to connect the lower part of the cylinder part 12 which protrudes into the crank chamber 17 and the skirt part 13 below the lower cylinder part /l. ing. This rib/S.

It is formed with oil at the center of the cylinder bore, parallel to the bulkhead 19 provided between the cylinder bores. Further, the skirt portion 15 formed in a substantially arc shape as described above bulges out most outwardly at a height position approximately in the middle of -f:, and becomes slightly narrower from there toward the lower end of the skirt portion/3. Ribs are provided between each cylinder bore and along the center of the cylinder bore so as to connect the substantially middle portion of the skirt portion 13 to the oil pan rail 20 at the lower end of the skirt portion 13. Note 1. The flap is a transmission mounting portion formed continuously at the rear end of the oil nozzle and rail unit O.

10,000, Figure 7 shows a cross section along the middle of adjacent cylinder bores, and as shown in the figure, between the cylinder bores, the water jacket outer wall /4' is the cylinder part /
A recess force is provided so as to be approximately parallel to the cylinder bore, and the unevenness of the wall surface prevents membrane perturbation of the outer wall of the water jacket. 7. Input Y from 44, crank soyaf),! The structure is such that the bulk hand lqK supported by 'i can be directly transmitted. Note that bearing camps 1 and 27 shown in FIG. 1 are oil pans attached to each bulkhead 19.

Now, in the above configuration, the water jacket outer wall/41 and the scar part/3 are continuously formed in an outwardly convex substantially arc shape, and the cross-sectional shape as a whole approximates a circle. Therefore, 1 The rigidity against the torsion and left/right bending shown in Fig. 2.8 described above is greatly improved, and these deformation vibrations are suppressed, and the opening/closing vibration of the skirt part 15 and the water jacket outer wall IQ accompanying these vibrations are suppressed. This makes it difficult for membrane vibration to occur, and the engine noise level can be significantly reduced by 7. In addition, the inner rib /g has the effect of more strongly suppressing the opening/closing vibration of the skirt part /5, and the outer rib 2/g connects the skirt part 15 and the oil rail 20 with This not only contributes to improving the left and right lateral bending rigidity of the cylinder block l/, but also has the effect of preventing undulating deformation vibration wJτ of the oil pan rail 20 and suppressing secondary sound generation i from the oil pan 27.

As is clear from the above description, the cylinder block for an automobile engine according to the present invention has a water jacket outer wall surrounding the cylinder m', a skirt part forming a crank chamber, and an outer part in a main cross section along the vicinity of the center of the cylinder bore. Since the cylinder block is formed continuously in a generally convex arc shape, the rigidity of the cylinder block against distortion and left/right bending deformation due to combustion is increased.

In addition, it is possible to suppress the opening/closing vibration of the skirt part, and reduce engine noise, especially IK, without significantly increasing weight.
The most problematic range around Hz can be effectively reduced.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional cylinder block, Figs. 2 and 3 are explanatory diagrams each showing an example of its vibration mode, Fig. 4 is a top view of the cylinder block according to the present invention, and Fig. 5
The figure is 9111 page %6+! ¥1 is ■ in Figure 4
7 is a sectional view taken along the line -■, and FIG. 7 is a sectional view taken along the same line <vn-vn. l/... cylinder block, /2... cylinder 1
llj, /$...Water jacket outer wall, /3...
・Skirt 9. , /It...Rip, /9...Bulkhead 1.21...Rib, ,7.4L...Nlinder\Sod bolt hole. Figure 1 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] (1) The outer wall of the water jacket that surrounds the cylinder part and the skirt part that forms the crank chamber are continuously formed in a substantially circular arc shape that is convex outward in the main cross section that extends near the center of the cylinder bore. Automotive engine cylinder block with % characteristics.