Method of manufacturing an engine block

A cylinder block for use in an internal combustion engine includes a first and second cylinder bores, a first and second cylinder bore liners, and a Siamese insert. The first and second cylinder bores are disposed adjacent to each other. The first and second cylinder bores each comprise a first cylinder bore wall and a second cylinder bore wall, respectively, and a shared cylinder bore wall. The first cylinder bore liner is disposed on a first inner surface of the first cylinder bore wall and the second cylinder bore liner is disposed on a second inner surface of the second cylinder bore wall. The Siamese insert is disposed in a top portion of the shared cylinder bore wall.

The present disclosure relates generally to the manufacture of Aluminum alloy engine block and more specifically to methods of manufacturing cast engine blocks having improved robustness while maintaining weight advantages over other alloys and processes.

The use of lightweight Aluminum alloys in cylinder blocks for internal combustion engines has greatly enhanced the vehicle energy efficiency by reducing the overall weight of the vehicle at the same time maintaining most of the capability of the cylinder block. Additional design adaptations to lighter and more compact engine systems have caused some challenges to continuing use of Aluminum alloys as the material of choice for some engine applications. For example, elevated heat stress in certain areas of the cylinder block have cause premature failures due to the geometry of the cylinder block and the inability to properly cool these areas.

Accordingly, there is a need in the art for an improved cylinder block design and method for manufacturing the new cylinder block that extends the useful life of the cylinder block in service, prevents catastrophic failure, and provides the design necessary to maintain and improve upon the use of lightweight Aluminum alloys for achieving fuel economy standards.

SUMMARY

The present disclosure comprises a cylinder block for use in an internal combustion engine. The cylinder block includes a first and second cylinder bores, a first and second cylinder bore liners, and a Siamese insert. The first and second cylinder bores are disposed adjacent to each other. The first and second cylinder bores each comprise a first cylinder bore wall and a second cylinder bore wall, respectively, and a shared cylinder bore wall. The first cylinder bore liner is disposed on a first inner surface of the first cylinder bore wall and the second cylinder bore liner is disposed on a second inner surface of the second cylinder bore wall. The Siamese insert is disposed in a top portion of the shared cylinder bore wall.

In one example of the present disclosure, the Siamese insert comprises a high temperature creep resistant alloy and the cylinder block comprises an Aluminum Alloy.

In another example of the present disclosure, the Siamese insert comprises an Aluminum-Bronze alloy having between about 8 to 10 wt. % Aluminum, Iron, Nickle, Manganese, Zinc, and Copper.

In yet another example of the present disclosure, the Siamese insert comprises an Aluminum-Bronze alloy having about 9.62 wt % Aluminum, 3.93 wt % Iron, 0.62 wt % Nickle, 3.36 wt % Manganese, 0.46 wt % Zinc, and the balance Copper.

In yet another example of the present disclosure, the Siamese insert comprises one of an Aluminum alloy, a steel alloy, a bronze alloy, and a ceramic-metal material.

In yet another example of the present disclosure, the Siamese insert comprises a top surface that includes a portion of a head deck sealing surface.

In yet another example of the present disclosure, the Siamese insert comprises a first and second bore liner pocket, the first bore liner is partially dispose in the first bore liner pocket, and the second bore liner is partially disposed in the second bore liner pocket.

In yet another example of the present disclosure, the shared cylinder bore wall comprises a first portion of the first cylinder bore liner, a second portion of the second cylinder bore liner, a third portion of the first cylinder bore wall, a fourth portion of the second cylinder bore wall, and the Siamese insert.

The present disclosure further comprises a cylinder block for use in an internal combustion engine. The cylinder block includes a first and second cylinder bores, a first and second cylinder bore liners, and a Siamese insert. The first cylinder bore liner is disposed on a first inner surface of the first cylinder bore wall and the second cylinder bore liner is disposed on a second inner surface of the second cylinder bore wall. The Siamese insert comprises a top surface and a high temperature creep resistant alloy. The Siamese insert is disposed in a top portion of the shared cylinder bore wall and the top surface includes a portion of a head deck sealing surface.

In one example of the present disclosure, the Siamese insert comprises an Aluminum-Bronze alloy having between about 8 to 10 wt. % Aluminum, Iron, Nickle, Manganese, Zinc, and Copper.

In yet another example of the present disclosure, the Siamese insert comprises one of an Aluminum alloy, a steel alloy, a bronze alloy, and a ceramic-metal material.

In yet another example of the present disclosure, the Siamese insert comprises a first and second bore liner pocket, the first bore liner is partially dispose in the first bore liner pocket, and the second bore liner is partially disposed in the second bore liner pocket.

In yet another example of the present disclosure, the shared cylinder bore wall comprises a first portion of the first cylinder bore liner, a second portion of the second cylinder bore liner, a third portion of the first cylinder bore wall, a fourth portion of the second cylinder bore wall, and the Siamese insert.

The present disclosure further comprises a method for manufacturing a cylinder block for an internal combustion engine. The method includes forming a sand core package and mold comprising a cylinder bore liner for each cylinder of the engine. The method further includes casting the cylinder block by pouring a liquid metal alloy into the mold, and cleaning and machining the cylinder block after cooling.

In one example of the present disclosure, forming the sand core package and mold comprising the cylinder bore liner for each cylinder of the engine further comprises forming the sand core package and mold comprising the cylinder bore liner for each cylinder of the engine and a Siamese insert disposed between each cylinder bore liner.

In another example of the present disclosure, casting the cylinder block by pouring the liquid metal alloy into the mold further comprises pouring a liquid Aluminum alloy into the mold to cast-in-place the cylinder bore liners and Siamese inserts.

In another example of the present disclosure, the method further includes fabricating a Siamese insert between each of the cylinder bore liners using a metal alloy additive technique.

In yet another example of the present disclosure, the method further includes fabricating a Siamese insert between each of the cylinder bore liners using at least one of laser cladding, cold/kinetic spray, and thermal spray metal adding techniques.

In yet another example of the present disclosure, the method further includes fixing a Siamese insert between each of the cylinder bore liners.

In yet another example of the present disclosure, the method further includes brazing a Siamese insert between each of the cylinder bore liners.

The above features and advantages and other features and advantages of the present disclosure are readily apparent from the following detailed description when taken in connection with the accompanying drawings.

DESCRIPTION

Examples of the present disclosure advantageously provide method of manufacturing a cylinder block10for an internal combustion engine. The cylinder block10, as depicted after various stages of the method inFIGS. 1-4, is arranged in a V8 configuration. However, other configurations of cylinder blocks10are considered without departing from the present disclosure. Preferably, at least two cylinder bores12of the cylinder block10are adjacent to each other and share a portion of a bore wall. Thus, inline, “V”, “W” or flat configurations may all be included in this disclosure. The cylinder block10includes several internal and external features including but not limited to cylinder bores12, internal water passages14, internal oil passages16, bolt bosses18, structural ribs20, and sealing surfaces22. More particularly, the cylinder bores12include a bore wall24having a top end26and a bottom end (not shown). The top end26is flush with a head deck sealing surface28while the bottom end is formed to terminate in a crankcase cavity (not shown). The bore wall24of a first cylinder bore30is shared with an adjacent second cylinder bore32. In this manner, an arrangement of cylinder bores30,32having common or shared bore walls36are considered to have a Siamese cylinder bore arrangement. One of the major benefits of having a Siamese cylinder bore arrangement is to shorten the length and to reduce the weight of the cylinder block10making a more compact engine package that provides the opportunity to save weight in other components of the vehicle.

Manufacturing a cylinder block10as shown inFIGS. 1-4includes casting iron or aluminum based alloys. When using aluminum based alloys, a cylinder bore liner34can be included to improve the wear characteristics of the surface38of the bore walls24. The cylinder bore liner34is formed from an iron based alloy and can be cast or press fit into the aluminum cylinder block10. Alternatively, the cylinder bore liner34can be sprayed onto the parent metal cylinder bore30,32using a plasma metal spraying technique or other manufacturing process.

Focusing more onFIGS. 3, 4, and 7, a cylinder block10including a Siamese insert40is illustrated. The Siamese insert40is disposed at the top end26of the shared bore wall36. The purpose of the Siamese insert40is to replace the cast Aluminum alloy in this area with an alternative alloy having improved high temperature characteristics. For example, a major source of failure of cylinder blocks10having Siamese bore arrangements is the deterioration of the aluminum alloy of the sealing surface22between the cylinder bores12due to high thermal loading and low creep resistance of the cast aluminum alloy. The high thermal loading is higher in this portion of the cylinder bores12due to the lack of internal water passages14in this area and receiving heat from adjacent cylinder bores30,32. Two major failure modes result. The first failure mode is the failure of the head gasket (not shown) to seal between the cylinder bores12and water passages14due to the recession of the aluminum alloy. The head gasket failure causes high pressure communication between the adjacent cylinders30,32. The second failure mode is increase cylinder bore12distortion thus causing the piston assembly to not seal against the bore wall24. This results in increased blow-by causing a reduction in fuel economy, increase in oil consumption, and poor emissions.

The Siamese insert40includes a sealing surface42, a first bore liner pocket44, a second bore liner pocket46, a first interface surface48, a second interface surface50, a first top ridge52, and a second top ridge54. The Siamese insert40, when displayed in a plan view as shown inFIG. 4, has an hourglass-like shape that conforms to the cylindrical shape of the first and second cylinder bores30,32. The first bore liner pocket44receives a bore liner34of the first cylinder bore30and the second bore liner pocket46receives a bore liner34of the second cylinder bore32. The first and second interface surfaces48,50are adjacent to and connect with the cylinder block10through the remaining portions of the cylinder bore walls24. The method of connection or attachment of the Siamese inserts40to the cylinder block10maybe any one of a number of metal joining techniques. For example, the Siamese insert40may be brazed or soldered into place. Additionally, the Siamese insert40may be cast into place in the same manner that the cylinder bore liners34are cast into place.

Turning now toFIG. 5, an example of a Copper based alloy for use in the Siamese inserts40is illustrated. The chart60provides a composition62for the Copper based alloy including about 9.62 wt % Aluminum Al, 3.93 wt % Iron Fe, 0.62 wt % Nickle Ni, 3.36 wt % Manganese Mn, 0.46 wt % Zinc Zn, and the balance Copper Cu. Additionally, data from testing of this particular alloy includes strength testing after several hours at high temperatures. For example, strength tests were run on samples after 100, 500, and 1000 hours at 200° C. and 300° C.

Referring now toFIG. 6, a method of manufacturing an aluminum cylinder block10is detailed and referred to as method100. The method100begins with a first step102as a sand core and sand mold or semi-permanent mold casting process by forming or blowing sand cores including a crankcase or cylinder bore core having a cast-in-place bore liner34for each cylinder bore. A second step104includes assembling the various individual sand cores of the sand core package. During the assembly of the sand cores a number of Siamese inserts40may be placed into the sand core package so that the Siamese inserts40are cast-in-place between the cylinder bores12. Alternatively, a third step106includes casting the cylinder block10without the Siamese inserts40. In this regard, a fourth step108may be to braise or otherwise join the Siamese inserts40to the cylinder block10between the cylinder bores12. Alternatively, a fifth step110includes fabricating the Siamese inserts40in the cylinder block10using an alloy adding technique such as laser cladding, cold/kinetic spray, thermal spray, and a combination of the alloy adding techniques. The alloy adding techniques include a deposition of a high creep strength alloy in place between the cylinder bores12forming the Siamese insert40. Other alloy adding techniques may be considered without departing from the scope of the disclosure. A sixth step112of the method100include machining the casting thus achieving a lightweight and compact Aluminum alloy cylinder block having high creep strength alloys disposed between the cylinder bores12at the sealing surface22of the cylinder head gasket.

While examples have been described in detail, those familiar with the art to which this disclosure relates will recognize various alternative designs and examples for practicing the disclosed structure within the scope of the appended claims.