Abstract: In a variable compression ratio internal combustion engine in which the compression ratio is changed by changing the combustion chamber volume, the present invention enables to inhibit irregularities in the air-fuel ratio involved by changing of the combustion chamber volume. In a transition period during which the compression ratio is changed, the actual volume of the combustion chamber realized by a compression ratio changing mechanism is detected. A factor that influences the air-fuel ratio (for example, fuel injection quantity, cylinder intake air quantity or amount of EGR) is controlled based on the actual volume of the combustion chamber thus detected to make the air-fuel ratio substantially equal to that before and after the change of the compression ratio.

Abstract: A foamed resin oil pan has a body portion and a flange portion for mounting the body portion on the cylinder block is disclosed. The bubble fraction of the resin constituting the body portion is higher than that of the resin constituting the flange portion. As a result, the strength and rigidity of the flange portion are maintained at high level while at the same time increasing the sound insulating properties and the heat insulating properties.

Abstract: In a variable compression ratio mechanism that serves to change the compression ratio of an internal combustion engine by rotating camshafts so as to cause relative movement between a cylinder block and a crankcase, an oil film forming device forms oil films on the sliding portions of camshafts.

Abstract: A variable compression ratio engine 100 has a compression ratio varying mechanism, which moves a cylinder block 103 relative to a lower case 104. The rotational driving force of a servo motor 112 is transmitted to vertical sliding movements of the cylinder block 103 by means of cam shafts 109 with eccentric cams. A row of first spring members 140 and a row of second spring members 150 are arranged on both sides of the cylinder block 103. The resultant spring force of the first spring members 140 and the second spring members 150 is applied to the cylinder block 103 and the lower case 104. The resultant spring force works to reduce the transmission torque of the rotational driving force of the servo motor 112 and assist the compression ratio varying mechanism to vary a compression ratio of the engine 100. The technique of the invention desirably simplifies the control procedure of varying the compression ratio of the engine and reduces the size of the mechanism required for this purpose.

Abstract: A foamed resin oil pan comprising a body portion and a flange portion for mounting the body portion on the cylinder block is disclosed. The bubble fraction of the resin constituting the body portion is higher than that of the resin constituting the flange portion. As a result, the strength and rigidity of the flange portion (3) are maintained at high level while at the same time increasing the sound insulating properties and the heat insulating properties.

Abstract: An engine including an intermediate shaft which is driven by the crankshaft and drives the camshaft. The intermediate shaft directly drives an oil pump arranged above the trans-axle and drives an alternator and compressor through a pulley connected to the intermediate shaft and a belt. The intermediate shaft is arranged shifted in the lateral direction from the plane containing the axes of the cylinders.

Abstract: The specification relates to an intake manifold having an increased compaction. In this intake manifold, at least one fragile zone is formed parallel to its longitudinal axis in its wall. Crash impact is absorbed and the volume of the intake manifold decreases after crashing, because its cross section is crushed. The intake manifold of this invention has an increased compaction and can prevent the structure around fuel injection valves from breaking.