Abstract: An intake system for an internal combustion engine includes first and second intake valve bores provided to face a combustion chamber and to be independently opened and closed by first and second intake valves, and first and second intake ports which are connected to the corresponding intake valve bores with a partition wall interposed therebetween and which communicate with a common intake passage. In a particular operation range of the engine, an imbalance is produced in the concentration of the air-fuel mixture flowing through the first and second intake valve bores into the combustion chamber on the basis of a difference between the amounts of fresh air flowing into the first and second intake ports. The intake system further includes a communication hole provided in the partition wall for putting the first and second intake ports into communication with each other. This provides for improvements in the lean combustibility and in the nature of the exhaust gas.

Abstract: An engine cooling system comprises a cooling water circulation circuit interconnecting an engine body and a radiator, a bypass circuit connected to the cooling water circulation circuit to bypass the radiator, an electric-powered water pump disposed in the cooling water circulation circuit adjacent an engine inlet, a flow rate control valve for controlling the flow rate of cooling water flowing through the radiator, an outlet water temperature detector for detecting an engine outlet water temperature in the cooling water circulation circuit, an inlet water temperature detector for detecting an engine inlet water temperature in the cooling water circulation circuit, and a control means for controlling the operation of the water pump in accordance with at least the engine outlet water temperature and controlling the operation of the flow rate control valve in accordance with at least the engine inlet water temperature to thereby properly control the temperature of the cooling water in accordance with the operat

Abstract: In a cooling system for a multi-cylinder engine, a main gallery is provided around outer peripheral portions of the plurality of cylinder bores upstream a block-side coolant jacket to commonly surround the cylinder bores, and an upstream coolant gallery is provided between the block-side coolant jacket and the main coolant gallery to separately surround each of outer peripheries of the cylinder bores. The upstream coolant gallery and the main coolant gallery is in communication with each other through a constriction communication passage provided around the outer periphery of each of the cylinder bores, and the upstream coolant gallery is further in communication with an upstream end of the block-side coolant jacket.

Abstract: A power unit mounting structure in a motor vehicle includes a power unit comprising an engine having a crankshaft, a transmission coupled to the crankshaft of the engine, and a differential interposed between drive axles connected to a pair of laterally spaced front road wheels of the motor vehicle and the transmission. The power unit is mounted in a front portion of the motor vehicle with its center of gravity positioned rearwardly of the drive axles extending from the differential toward front road wheels serving as the drive road wheels. A steering gearbox extends parallel to the drive axles and is disposed forwardly of the drive axles.

Abstract: A cylinder block as a main part of an engine block includes a cylinder barrel assembly block, a skeleton-like frame surrounding the outer periphery of the cylinder barrel assembly block and a plate-like rigid film member, within a fluid passage in the skeleton-like frame. The skeleton-like frame is integrally joined to the outer surfaces of left and right side walls of the assembly block along the crankshaft axis and includes crossbeam bone members, longitudinal beam bone members and post bone members which are rigid and unitarily assembled into a three-dimensional latticework structure. A cylinder head is integrally coupled to the deck surface of the cylinder block and a lower case is integrally coupled to the lower surface of the cylinder block, lateral outer surfaces of the block and lower case along the crankshaft axis being formed flush with each other in parallel with the cylinder bore axis.

Abstract: An oil pan structure for the cylinder block of an internal combustion engine for storing lubricating oil in the oil pan. A volume body submergible at least partly below the oil level for displacing a volume of oil when the oil is titled by displacement to one side in the oil pan as a result of the running condition of the motor vehicle having the engine with the oil pan structure, such as during turning, acceleration, deceleration or banking. The volume body has an inlet opening positioned near an allowable upper limit oil level for a predetermined maximum oil tilting condition for introducing into the volume body the lubricating oil which exceeds the allowable upper limit oil level. The oil pan structure also has an oil discharge passage from the lower portion of the volume body.

Abstract: An optically active s-triazine derivative having at least two asymmetric carbon atoms of the general formula: ##STR1## wherein n is 2 to 3; and X and Y are the same or different and are each a member selected from the group consisting of the groups: ##STR2## WHEREIN M IS 1 TO 3; AND R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are the same or different and are each an alkyl having 1 to 12 carbon atoms, a cycloalkyl having 5 to 6 carbon atoms, phenyl or benzyl, and a gas chromatographic method for the resolution and analysis of the mixture of enantiomers having an --NH-- group linked to an asymmetric carbon atom, comprising using said derivative as an optically active stationary phase for the gas chromatography.