Abstract:
In a bearing cap of the type which is bolted to a bearing support structure so as to define a bearing bore between the cap and the structure and in which bolt holes for securing the cap to the structure extend through feet of the cap and into the structure, the cap having at least two of the feet, one foot on each side of the bore with at least one bolt hole extending through each foot, the improvement wherein:the cap is sintered powder metal and has an integral boss protruding from the foot around the bolt hole.
Abstract:
A bearing arrangement which assures positive geometrical centering between two separately produced bearing components, preferably in internal combustion engines, includes a first bearing component provided with projections extending beyond a parting surface between the components and a second bearing component of lower hardness than the projections so that the projections displace the material of the second bearing component during assembly of the bearing arrangement.
Abstract:
A reinforcing insert for an engine block formed of a lightweight material is provided which is positioned in the bearing saddle area of the block for increasing the strength and stiffness of the bearing saddle area to ensure a secure connection of the main bearing cap throughout engine operation thereby ensuring proper crankshaft support and operation. The reinforcing insert is formed of a material having a higher modulus of elasticity than a modulus of elasticity of the lightweight engine block material. The insert includes a lower transverse surface for positioning at a lowermost position in the engine block, an upper surface positioned farthest from the crankshaft, a first and second linear side surfaces for positioning on opposite sides of the crankshaft. The linear sides extend from the lower surface along respective planes in nonparallel relation to each other. The linear sides may extend either in a converging or a diverging manner from the lower surface. Alternatively, the insert may include two cylindrical inserts positioned in bores formed in the block on opposite sides of the crankshaft. These insert designs provide strengthening and stiffening of the block over an optimum area while permitting secure attachment of a main bearing cap to the lightweight block.
Abstract:
The crankshaft bearing for an internal combustion engine consists of two bearing sections bolted together, in which an insert made of a ferrometallic material is embedded in a casting made of a light metal alloy. The inserts consist of shaped molded parts with openings and thickenings as well as a semicircular carrier that receives the respective part of the bearing bore. The inserts are traversed by the bearing bolts, which on one side abut the outer bolt surfaces on the casting of one bearing section and are bolted into the casting of the other bearing section.
Abstract:
A bearing insert for being cast into an aluminum alloy engine block is made by a ferrous powder metal sintering process to make a skeleton structure which is permeable to the molten aluminum alloy in the block casting process. The insert is made of a material having a similar composition as the bearing cap so as to equalize machining and thermal expansion properties of the cap and block so as to provide improved roundness of the bearing in the machining operations for forming the bearing support and in operation of the engine.
Abstract:
A cylinder block has a cylinder block body and a cylinder liner block mounted by casting in the cylinder block body. The cylinder liner block is formed from a material having a rigidity larger than that of the cylinder block body, and the cylinder liner block comprises a liner section mounted by casting in position in a cylinder barrel portion of the cylinder block body, and a reinforcing wall section mounting by casting in position in a bearing wall of a crank case portion of the cylinder block body in a. Thus, it is possible to increase the wear resistance of cylinders in the cylinder block, as well as to provide an increase in performance by reductions in vibration and noise of the engine including the cylinder block, and to provide reductions in size, weight and cost of the cylinder block by a reduction in thickness of the bearing walls.
Abstract:
A main bearing cap for an internal combustion engine consists of an aluminum alloy with a steel core (6). The cap has a supporting surface (2) for the bearing shell (3). The supporting surface is the outer surface of a 3 mm thick aluminum layer (10) outside the steel core.
Abstract:
A cylinder block for an engine is formed of a cylinder block body and a lower block which are cast from aluminum alloy and are fastened together to support therebetween a crankshaft of the engine. The upper half of a bearing portion for supporting the crankshaft is provided in the cylinder block body and the lower half of the bearing portion is formed by a bearing cap cast in the lower block. A method of manufacturing the cylinder block includes the steps of casting the cylinder block body and the lower block with the bearing cap cast in the lower block, fastening together the cylinder block body and the lower block by bolts, performing primary stage finishing of the bearing portion with the cylinder block body and the lower block kept fastened together, releasing the lower block from the cylinder block body after the primary stage finishing of the bearing portion and permitting the lower block to deform under stress produced by shrinkage of aluminum alloy, fastening again the cylinder block body and the lower block together by the bolts, and performing final stage finishing of the bearing portion with the cylinder block body and the lower block kept fastened together.
Abstract:
An internal combustion engine having a cylinder block made of a light-alloy with a cylinder wall around a cylinder bore including a cylindrical fiber-reinforced portion which is formed of a mixture of an alumina-based fiber and a carbon fiber with a light-alloy matrix. The alumina-based fiber has a fiber volume fraction set in a range of 8 to 20%, and the carbon fiber has a fiber volume fraction set in a range of 0.3 to 15%. The alumina-based fiber contains 25% or less, by weight, of silica, has an average aspect ratio of 20 to 150, and an alpha rate of 2 to 60%. The carbon fiber has an average aspect ratio set in a range of 10 to 100 and a Young's modulus set in a range of 20 to 30 t/mm.sup.2. The piston for the cylinder bore has an iron-plated layer covered by a tin-plated layer. The piston rings for the piston may be of austenitic stainless steel to provide thermal expansion characterics similar to the cylinder wall and may be provided with a nitride or chromium-plated layer.
Abstract:
A crankshaft supporting structure in a multicylinder internal combustion engine has a cylinder block made of a light alloy and including a cylinder housing and a crankcase having a plurality of spaced journal walls. A plurality of spaced bearing caps made of an iron alloy are coupled respectively to the journal walls. A crankshaft is rotatably supported in bearing holes defined by the journal walls and the bearing caps. A bridge made of a light alloy extends across the bearing caps and is coupled to the bearing caps. The bearing caps and the bridge are fastened together to the journal walls by connecting bolts disposed one on each side of the crankshaft. The bridge has a main portion defining a main gallery extending longitudinally therethrough and a plurality of legs coupled to the bearing caps, respectively. The bearing caps and the legs jointly define branch oil passages communicating with the main gallery and the bearing holes. In one embodiment, each of the oil passages has a longitudinal central axis displaced transversely from the central axis of the cylinder housing passing through the center of the crankshaft.