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 mounted by casting in position in a bearing wall of a crank case portion of the cylinder block body. 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 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: An evaporative fuel emission control system for an internal combustion engine has a canister connected to a fuel tank of the engine. The canister temporarily stores evaporative fuel generated from the fuel tank. The evaporative emission control system also includes a purging passage connecting the canister and a portion of an intake passage at a location downstream of a throttle valve arranged in the intake passage. An amount of evaporative fuel is increased which is generated from the fuel tank. In a preferred form, the system includes a second fuel tank arranged between the first-mentioned fuel tank and the canister. Evaporative fuel is increased by evaporating fuel in the second fuel tank.

Abstract: A control unit for an internal combustion engine that compensates for variations in injection valve flow rate characteristics by detecting an operation status of the engine and then using this status information to calculate a supply air amount or supply fuel amount in accordance with the detected status. Exhaust gas constituents are detected and then used to correct the calculated supply air or supply fuel amount. The control unit compares the exhaust gas constituents with predetermined values and then uses a neural network to control the supply air amount or supply fuel amount to make any deviation between the exhaust gas constituents and the predetermined value approach zero.

Abstract: Method and system for detecting a level of an engine oil of an engine include an operation for detecting a time duration in which the engine is operating. When the engine operation has continued for more than a predetermined time period, and the engine is stopped subsequently, the oil level is detected after the elapse of a second predetermined time period in which the engine is stopped. By this feature, the engine oil level is detected very accurately.

Abstract: Method and system for detecting a level of an engine oil of an engine includes an operation for detecting a time duration in which the engine is operating. When the engine operation has continued for more than a predetermined time period, and the engine is stopped. Subsequently, the oil level is detected after the elapse of a second predetermined time period in which the engine is stopped. By this feature, the engine oil level is detected very accurately.

Abstract: An intake manifold assembly of a variable intake passage length includes a branch passage body for introducing air from a main throttle valve into intake ports of an engine. The branch passage body has an intake chamber communicating with the main throttle valve, a plurality of shorter passages extending upwardly from the intake chamber and each having an auxiliary throttle valve for selectively opening and closing the shorter passage, a plurality of longer passages extending from the intake chamber around a lower side of the intake chamber, the shorter and longer passages having downstream ends joined to each other at respective junctions, and connected to the intake ports.

Abstract: An intake manifold for an internal combustion engine wherein individual intake passages communicate between an air distribution chamber and each engine cylinder. Separate bypass passages extend from the distribution chamber and each intake passage at a downstream location to provide a substantially shorter effective passage to the engine cylinders and a valve in each bypass passage is operated in response to engine speed to open the bypass passages at high engine speeds.

Abstract: A crankcase ventilating system removes engine oil particles from a gas containing a blow-by gas and drawn from an engine crankcase, and then introduces the gas into an intake manifold. The crankcase ventilating system includes a first chamber for passing a gas from the crankcase therethrough, a valve for controlling the amount of the gas flowing therethrough, and a second chamber for passing therethrough the gas flowing from the first chamber via the valve and for allowing the gas to flow from the second chamber into the intake manifold. The second chamber is arranged to permit the gas to be expanded therein. The crankcase ventilating system can separate fuel and water from the engine oil.

Abstract: An air intake system for an internal combustion engine wherein the intake port to a combustion cylinder is connected to a trunk portion of the intake system which contains the throttle valve. A high speed intake passage of a relatively short length and a slow speed intake passage of a relatively long length are both connected to the trunk portion with a control valve in the high speed intake passage. The control valve is opened for high speed operation of the engine and closed for slow speed operation to operatively select between the two intake passages. In modified embodiments the degree of opening of the control valve is modulated in proportion to the r.p.m. of the engine.