Cylinder block for V-type engine

A V-type engine cylinder block includes a mounting pedestal, integrally formed with the block in a V-shaped space between two cylinder banks and interconnecting the cylinder banks. A top wall is secured to the mounting pedestal and extends over almost the entire length of the V-shaped space in a lengthwise direction of the cylinder block. A plurality of bosses are formed with internal threads for securing a bracket, for mounting the cylinder block onto a car body, to one end wall of the cylinder block by bolts. The mounting pedestal and bosses are interconnected by ribs integrally formed with the cylinder block.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to the structure of a cylinder block for an 
automotive engine and, more particularly, to an engine block structure for 
a V-type internal combustion engine. 
2. Description of Related Art 
Typically, a known V-type internal combustion engine has a cylinder block 
and a cylinder head mounted on the cylinder block. The cylinder block 
consists of two cylinder banks arranged in a V-formation, having a 
predetermined relative angle, for example, a relative angle of 60 degrees, 
therebetween. Such a V-type engine, during operation, causes the cylinder 
banks to rapidly move away from and toward each other and produces 
vibrations of the cylinder block between the cylinder banks. Such 
vibrations produce noise in the passenger compartment of a car. 
Usually, the V-shaped space between the cylinder banks is utilized so that 
various elements or structural parts can be installed on the engine. For 
instance, as is known from Japanese Unexamined Patent Publication No. 
59-188019, a pressure buffer chamber for blow-by gas is provided in the 
V-shaped space formed between the two cylinder banks. For this purpose, 
the V-type engine is provided with a top wall in the V-shaped space for 
forming the blow-by gas pressure buffer chamber on the V-type engine. The 
top wall typically connects the banks, so as to function as a 
reinforcement for restraining the motion of the banks away from and toward 
each other. This contributes to reducing vibration of the cylinder block. 
SUMMARY OF THE INVENTION 
It is a primary object of the present invention to provide an engine block 
structure which causes an engine block to produce less vibration. 
The primary object of the present invention is achieved by providing a 
novel cylinder block structure for a V-type internal combustion cylinder, 
which has two cylinder banks, each formed with more than two cylinders 
arranged in a V-formation, at a predetermined relative angle, so as to 
form therebetween a V-shaped space. The cylinder block includes mounting 
means, such as a rib formed in a shape of ladder, integrally formed with 
the cylinder block in the V-shaped space so as to interconnect the 
cylinder banks. A top wall, extending along almost the entire length of 
the V-shaped space, is secured to the mounting means. A plurality of 
bosses, formed with internal threads and extending into the V-shaped 
space, secure a bracket for mounting the cylinder block on a car body to 
one end wall of the cylinder block by bolts. The mounting means and bosses 
are interconnected by rib means integrally formed with the cylinder block. 
The top wall may include a wall section secured to the mounting means and a 
pipe section integrally formed with the wall section which forms part of a 
suction pipe of an engine cooling system installed in the engine including 
the cylinder block. 
The mounting means for the top wall is reinforced by the rib means 
connected to the bosses. This effectively restrains the movement of the 
cylinder banks away from and toward each other, thereby helping to improve 
the rigidity of the cylinder block and, therefore, reducing vibration of 
the cylinder block. 
Thus, the rib means reinforces the bosses and, consequently, vibration 
produced by the engine is prevented from being transmitted to the car body 
through the mounting bracket, so as to reduce noise in the car body.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to the drawings in detail and, in particular, to FIGS. 1 to 8, a 
cylinder block 1, for a V-type, six-cylinder internal combustion engine, 
in accordance with a preferred embodiment of the present invention, is 
shown. The engine includes first and second, or left and right, cylinder 
banks 2 and 3 arranged in a V-formation with a predetermined relative 
angle, for example, a relative angle of 60 degrees, therebetween. Each 
cylinder bank 2 and 3 is formed with three cylinder bores i.e., bores 4, 
5, 6 and 7, 8 and 9, respectively, in a straight line. A piston (not 
shown) slides in each cylinder bore. 
The cylinder block 1 is provided with a housing 10 for a water pump A, 
formed in the front wall 1a at almost a center portion. The water pump 
housing 10 is formed with a center recess 10a for allowing a rotor 12 of 
the water pump A to operate. The water pump housing 10 is further formed 
with a suction opening 45 opening into the recess 10a. Water inlets 10b 
and 10c are in communication with water passages (not shown) in the first 
and second cylinder banks 2 and 3, respectively. 
As is clearly shown in FIG. 3, the water pump housing 10 receives the rotor 
12 operatively therein. Rotor 12 is covered by a cover 11. The housing 10 
also receives a rotary shaft 13 and a pulley 14 secured to an outer end of 
the rotary shaft 13. The pulley 14 is connected or coupled to the 
crankshaft (not shown) of the engine by a belt, which transmits the engine 
output to drive the pulley 14. 
Cylinder block 1 is provided with a bracket 15 for mounting the cylinder 
block 1 onto a car body. Bracket 15 is secured to the front wall la above 
the water pump housing 10 by bolts 16. As is shown in FIG. 2, the front 
wall 1a of the cylinder block 1 is formed with bosses 18 including 
threaded bores 17 disposed above the water pump housing 10. The inner two 
of these bosses 18 project into a V-shaped space 19 formed between the 
first and second cylinder banks 2 and 3. 
Cylinder block 1 is formed with a vertical bore 20, surrounded by a bank 
21, opening into the V-shaped space 19 at a center portion in a lengthwise 
direction of the V-shaped space 19. The bore 20 receives therein a knock 
sensor 24, which itself is well known in the art. As is shown in detail in 
FIGS. 4 and 5, the bank 21 extends between the center cylinders 5 and 8 of 
the respective cylinder banks 2 and 3. In more detail, the bank 21 extends 
beyond water jackets 23 surrounding the center cylinders 5 and 8 of the 
respective cylinder banks 2 and 3 and adjoins liners 5a and 8a for the 
center cylinders 5 and 8. The knock sensor 24 in the vertical bore 20 can 
detect directly knocking of the cylinders 5 and 8. This avoids or 
decreases adverse effects of noise produced by the engine, since the 
threshold sensitivity of the knock sensor 24 to knocking of the cylinders 
5 and 8 can be set to a high level. 
The cylinder block 1 is further formed, in the V-shaped space 19, with a 
pedestal 31, such as a lattice or ladder shaped rib, with threaded bores 
32 at proper positions. A top wall 30, having its whole length sufficient 
to extend from the front to the back, in a lengthwise direction, of the 
cylinder block 1, is secured to the pedestal 31 by bolts 33 so as to cover 
the knock sensor 24. The pedestal 31 is connected by ribs 34 to the inner 
bosses 18 provided at the front wall 1a of the cylinder block 1. One end 
of each rib 34 is desirably connected to the pedestal 31 at a portion 
where the threaded bore 32 is formed. The ribs 34, thus provided, 
reinforce the bosses 18 attached to the bracket 15. On the other hand, the 
pedestal 31, connecting the cylinder banks 2 and 3, restrains the movement 
of the cylinder banks 2 and 3 away from and toward each other, and the 
cylinder block 1 has a high torsional and a high bending rigidity at the 
portion where the bosses 18 are formed. This contributes to reducing the 
transmission of engine vibration to the car body. 
Cooling water is introduced from the water pump A through the water inlets 
10b and 10c into the first and second banks 2 and 3, respectively. While 
the engine is heated, the cooling water in the cylinder block 1 is 
discharged into a radiator 41 through a water outlet 40 formed in the 
front wall 1a. After being cooled in the radiator 41, the cooling water is 
returned into the water pump A through the suction opening 45 via a return 
pipe 42 provided with a thermostat valve 43 disposed at the rear end of 
the cylinder block 1 and then a suction pipe 44 disposed directly above 
the top wall 30 in the V-shaped space 19. The suction pipe 44 is connected 
to the suction opening 45 through a suction passage 46 (see FIG. 8) formed 
in the cylinder block 1. 
While the engine is cooled, the cooling water in the cylinder banks 2 and 3 
is introduced to the water pump A through the thermostat valve 43 via a 
bypass pipe 47 and then the suction pipe 44. The bypass pipe 47 is, as is 
shown in FIG. 8, disposed above the suction pipe 44 in the V-shaped space 
19. 
The suction pipe 44 comprises three elemental parts, namely, a first, or 
rear, connection pipe 44a disposed at the rear end of the cylinder block 
1, an L-shaped second, or front, connection pipe 44b disposed at the front 
end of the cylinder block 1, and a straight central pipe 44c extending in 
the V-shaped space 19. The first connection pipe 44a is secured by bolts 
48 (see FIG. 4) to a casing of the thermostat valve 43, which is bolted to 
the cylinder block 1, at one end, and is connected to the central pipe 44c 
at the other end. The second connection pipe 44b, which is bolted to the 
cylinder block 1, is joined through a boss 44b to the central pipe 44c at 
one end and is connected to an opening 46a of the suction passage, opening 
into the V-shaped space 19, at the other end. 
According to the structure of the cylinder block described above, because 
the top wall 30 is bolted to the ladder shaped pedestal 31, extending 
along almost the whole length of the cylinder block 1 in the V-shaped 
space 19, and the ladder shaped pedestal 31 is connected to the bosses 18 
for mounting the bracket 15, the ladder shaped pedestal 31 is improved in 
rigidity, so as to effectively restrain the movement of the cylinder banks 
2 and 3 away from and toward each other. Therefore, since the cylinder 
block 1 is prevented from producing vibration, the connection between the 
L-shaped second connection pipe 44b and the straight central pipe 44c is 
prevented from loosening due to vibrations. 
Referring to FIG. 9, a variant of the cylinder block according to the 
preferred embodiment of the present invention described above is shown. 
The variant shown in FIG. 9 includes a top wall portion 30' with which a 
suction pipe portion 44' (including the L-shaped second connection pipe 
44b and the straight central pipe 44c of the previous embodiment) is 
integrally formed as a unit. Installing the unit to the cylinder block 1 
is performed simply by securing, at first, the top wall portion 30', by 
bolts 50, to the ladder shaped pedestal 31, and then securing the suction 
pipe portion 44', by the bolts 48, to a connecting pipe 44a' previously 
assembled to the casing B of the thermostat valve 43. 
According to this embodiment, the top wall is reinforced by the suction 
pipe partly integrally formed with the top wall. This restrains more 
effectively the movement of the cylinder banks 2 and 3 away from and 
toward each other, so as to reduce the vibration produced by the cylinder 
block 1. 
It is to be understood that although the present invention has been 
described in detail with respect to preferred embodiments thereof, various 
other embodiments and variants are possible which fall within the scope 
and spirit of the invention, and such embodiments and variants are 
intended to be covered by the following claims.