Abstract: A bearing cap (1) is attached to a bulkhead (22) of a cylinder block (21) made of a light metal through a pair of bolts (24). The bearing cap (1) has a frame (2) made of an iron-based metal and a cast light-alloy part (3). The frame (2) has a pair of pillar parts (9) through which the bolts (24) extend and a circular-arc-shaped arch section (10). At high temperatures, the span of the pair of the bolts (24) increases due to thermal expansion of the light-alloy material, and the pair of the pillar parts (9) expand. This causes the middle part of the arch section (10) to shift upward, thereby suppressing an increase in bearing clearance.

Abstract: A crankshaft of an in-line, four-cylinder internal combustion engine has five journal portions. The journal portions are each supported by a main bearing unit. Each of the main bearing units includes a cylinder block side bearing part and a bearing cap. The No. 1, No. 2, No. 4 and No. 5 main bearing units employ an iron-based bearing cap, and the No. 3 main bearing unit at the center employs a bearing cap made of an aluminum alloy having a relatively high thermal expansion coefficient. At high temperatures, the bearing clearance of the No. 3 main bearing unit is configured to expand so as to reduce bearing load.

Abstract: A bearing cap (1) is attached to a bulkhead (22) of a cylinder block (21) made of a light metal through a pair of bolts (24). The bearing cap (1) has a frame (2) made of an iron-based metal and a cast light-alloy part (3). The frame (2) has a pair of pillar parts (9) through which the bolts (24) extend and a circular-arc-shaped arch section (10). At high temperatures, the span of the pair of the bolts (24) increases due to thermal expansion of the light-alloy material, and the pair of the pillar parts (9) expand. This causes the middle part of the arch section (10) to shift upward, thereby suppressing an increase in bearing clearance.

Abstract: A crankshaft of an in-line, four-cylinder internal combustion engine has five journal portions. The journal portions are each supported by a main bearing unit. Each of the main bearing units includes a cylinder block side bearing part and a bearing cap. The No. 1, No. 2, No. 4 and No. 5 main bearing units employ an iron-based bearing cap, and the No. 3 main bearing unit at the center employs a bearing cap made of an aluminum alloy having a relatively high thermal expansion coefficient. At high temperatures, the bearing clearance of the No. 3 main bearing unit is configured to expand so as to reduce bearing load.

Abstract: Cover (25) is mounted on wall surface (12) on the front side of cylinder block (10). Sub gallery (26) through which engine oil flows is formed between cover (25) and wall surface (12). Chain tensioner (17) is mounted on cover (25), and the engine oil in sub gallery (26) is supplied to chain tensioner (17) through oil supply port (31) formed through cover (25).

Abstract: Cover (25) is mounted on wall surface (12) on the front side of cylinder block (10). Sub gallery (26) through which engine oil flows is formed between cover (25) and wall surface (12). Chain tensioner (17) is mounted on cover (25), and the engine oil in sub gallery (26) is supplied to chain tensioner (17) through oil supply port (31) formed through cover (25).

Abstract: A method for processing a cylinder block is disclosed, wherein a protrusion protruding toward a crankcase is provided at a crankcase-side edge of a cylinder bore and a sprayed coating is formed on an inner surface of the cylinder bore and an inner surface of the protrusion continuous with the inner surface of the cylinder bore. After forming the sprayed coating, at least part of the protrusion is removed together with the sprayed coating formed on the inner surface of the protrusion. Accordingly, even in the case of removing the edge portion of the cylinder bore on the crankcase side, a sufficient margin to be removed can be ensured while a reduction in size of the cylinder block is achieved.

Abstract: An iron-based metal bearing cap according to the present invention to be cast as a core into a light metal member includes an arcuate portion which forms a bearing surface, left and right flange portions which are arranged and connected to opposite ends of the arcuate portion, and boss portions which are arranged to stand on the rear surfaces of the left and right flange portions and through which mounting bolts are inserted. The bosses are formed with grooves or projections.

Abstract: An iron-based metal bearing cap according to the present invention to be cast as a core into a light metal member includes an arcuate portion which forms a bearing surface, left and right flange portions which are arranged and connected to opposite ends of the arcuate portion, and boss portions which are arranged to stand on the rear surfaces of the left and right flange portions and through which mounting bolts are inserted. The bosses are formed with grooves or projections.

Abstract: A method for processing a cylinder block is disclosed, wherein a protrusion protruding toward a crankcase is provided at a crankcase-side edge of a cylinder bore and a sprayed coating is formed on an inner surface of the cylinder bore and an inner surface of the protrusion continuous with the inner surface of the cylinder bore. After forming the sprayed coating, at least part of the protrusion is removed together with the sprayed coating formed on the inner surface of the protrusion. Accordingly, even in the case of removing the edge portion of the cylinder bore on the crankcase side, a sufficient margin to be removed can be ensured while a reduction in size of the cylinder block is achieved.

Abstract: Blow-by gas in a plurality of crank chambers (71-73) in a V-shaped internal combustion engine is led to a plurality of gas introducing chambers (9a, 9b, 9c) via communicating holes (11-14). The blow-by gas then flows into an oil separator (31), which extends in a front-aft direction of the internal combustion engine, from the gas introducing chambers (9a, 9b, 9c). The blow-by gas inlet (33) of the oil separator (31) is provided in the vicinity of the engine front or the engine rear. By providing a guide member (35, 41) which guides the blow-by gas from the gas introducing chamber (9a) which is closest to the blow-by gas inlet (33) to the blow-by gas inlet (33) in a direction heading away from the blow-by gas inlet (33) and then guides it to the blow-by gas inlet (33), pumping loss in the internal combustion engine can be reduced.

Abstract: A method of manufacturing a cylinder block for a multi-cylinder engine is disclosed herein. The cylinder block includes a crankcase and cylinder bores disposed therein separated by cylinder walls. The crankcase is adapted to receive a crankshaft and includes crank chambers disposed therein separated by partition walls. Each of the crank chambers of the crankcase corresponds to one of the cylinder bores of the cylinder block. The cylinder bore side of each partition wall has a honing runoff portion thinner in section than the crankshaft side thereof such that a step face results in the partition walls. Further, a runoff groove is formed in the partition walls of the crank chambers, and also a communication hole is formed at least partially within the runoff groove in at least one of the partition walls to enable communication between crank chambers.

Abstract: Blow-by gas in a plurality of crank chambers (71-73) in a V-shaped internal combustion engine is led to a plurality of gas introducing chambers (9a, 9b, 9c) via communicating holes (11-14). The blow-by gas then flows into an oil separator (31), which extends in a front-aft direction of the internal combustion engine, from the gas introducing chambers (9a, 9b, 9c). The blow-by gas inlet (33) of the oil separator (31) is provided in the vicinity of the engine front or the engine rear. By providing a guide member (35, 41) which guides the blow-by gas from the gas introducing chamber (9a) which is closest to the blow-by gas inlet (33) to the blow-by gas inlet (33) in a direction heading away from the blow-by gas inlet (33) and then guides it to the blow-by gas inlet (33), pumping loss in the internal combustion engine can be reduced.

Abstract: A method of manufacturing a cylinder block for a multi-cylinder engine is disclosed herein. The cylinder block includes a crankcase and cylinder bores disposed therein separated by cylinder walls. The crankcase is adapted to receive a crankshaft and includes crank chambers disposed therein separated by partition walls. Each of the crank chambers of the crankcase corresponds to one of the cylinder bores of the cylinder block. The cylinder bore side of each partition wall has a honing runoff portion thinner in section than the crankshaft side thereof such that a step face results in the partition walls. Further, a runoff groove is formed in the partition walls of the crank chambers, and also a communication hole is formed at least partially within the runoff groove in at least one of the partition walls to enable communication between crank chambers.