[0001] The present invention relates to a perfected internal combustion engine block.
[0002] Smooth operation of the said engines is known to depend on maintaining the engine
components subject to most thermal stress at a temperature compatible with the functions
performed by such components. This therefore means cooling the engine blocks, in particular,
the most critical points on the same, such as the portions between two adjacent cylinders,
which, being of very limited thickness, do not allow for sufficient coolant circulation.
[0003] At present, a cavity is formed about each cylinder and communicating externally via
vertical holes. Inside the portions extending between two adjacent cylinders, provision
is made for two such vertical holes, one for each cavity and, therefore, one for each
cylinder. On certain types of engine blocks, the cavities of two adjacent cylinders
communicate via a third cavity formed by casting; on other types, the vertical holes
of two adjacent cavities communicate via an oblique hole or by removing material off
the cylinder head.
[0004] The aim of the present invention is to provide a perfected internal combustion engine
block enabling improved cooling as compared with known blocks of the aforementioned
types. With this aim in view, according to the present invention, there is provided
a perfected internal combustion engine block having a coolant circulating circuit
comprising a cavity for each cylinder, characterised by the fact that, in the portion
between two adjacent cylinders, there extends, from each said cavity, an oblique hole
communicating externally and intersecting a corresponding oblique hole extending from
the said cavity of the said adjacent cylinder.
[0005] A preferred embodiment of the present invention will be described by way of example
with reference to the accompanying drawings in which :
Fig.1 shows a partial section of an internal combustion engine block;
Fig.2 shows an enlarged section of a detail on the Fig.1 block.
[0006] Number 1 in Fig.1 indicates a perfected block for known types of internal combustion
engines. About each cylinder, there is formed a cavity 2 communicating externally
via two vertical holes 3 each formed in the portion of block 1 extending between two
adjacent cylinders. According to the present invention, the said holes 3 of adjacent
cavities 2 communicate via two oblique, centrally-intersecting holes 4, the said intersection
defining, on block 1, a triangular-section portion 5 having its tip situated at the
said point of intersection and the other two tips located at the top ends of two adjacent
said holes 3. Cavities 2 and holes 3 and 4 define a circuit in which to circulate
coolant, preferably water containing antifreeze and passivators for preventing corrosion.
The said circuit forms part of a known type of cooling system which, depending on
the type of application, may be a consumption or total/partial feedback type.
[0007] By means of a duct (not shown), each cavity 2 is fed, e.g. by means of a pump, with
coolant which flows out through holes 3, part of the said coolant flowing into adjacent
hole 3 via communicating hole 4. At the said point of intersection, the mean speeds
(VI and V2 in Fig.2) of the coolant flowing in holes 4 combine to give a resultant
(V3) directly incident with the tip of portion 5, and the resulting swirl of which
provides for improved heat exchange between the coolant and the said portion 5.
[0008] The advantages of the engine block according to the present invention will be clear
from the foregoing description.
[0009] In particular, improved cooling provides for greater reliability of the components
subject to overheating in the area in question, i.e. cylinders, pistons, piston rings,
etc., thus reducing wear on the said components and, consequently, maintenance cost
of the same. Improved engine performance may also be obtained without subjecting the
block to critical operating temperatures. Furthermore, the centre distance between
the cylinders may also be reduced at the design stage, for so reducing the length
of the engine. Finally, block 1 provides for greater cooling efficiency, as compared
with known types of blocks, as well as for lower manufacturing cost, as compared with
blocks having a cast connecting cavity between two annular cavities; which solution,
despite the improvement it affords in terms of cooling, is complex in design, expensive
to manufacture and reduces the rigidity of the block.
[0010] To those skilled in the art it will be clear that changes may be made to block 1
as described and illustrated herein without, however, departing from the scope of
the present invention.
1) - A perfected internal combustion engine block having a coolant circulating circuit
comprising a cavity (2) for each cylinder, characterised by the fact that, in the
portion between two adjacent cylinders, there extends, from each said cavity (2),
an oblique hole (4) communicating externally and intersecting a corresponding oblique
hole (4) extending from the said cavity (2) of the said adjacent cylinder.
2) - An engine block as claimed in Claim 1, characterised by the fact that the said
oblique holes (4) of the said two adjacent cavities (2) intersect centrally, so as
to define, in the said portion extending between two adjacent cylinders, a substantially
triangular-section portion (5).
3) - An engine block as claimed in Claim 1 or 2, characterised by the fact that, in
the said portion extending between two adjacent cylinders, there extends, from each
of the said cavities (2), a vertical hole (3).
4) - An engine block as claimed in Claim 3, characterised by the fact that each of
the said oblique holes (4) extends from a corresponding vertical hole (3), in the
proximity of the connecting point between the said vertical hole (3) and the respective
said annular cavity (2), and, subsequent to intersecting the corresponding said oblique
hole (4), comes out at the top end of the corresponding vertical hole (3) extending
from the said cavity (2) adjacent to the aforementioned said cavity (2).
