Abstract: A lubricating mechanism for a rotary machine, such as a Roots blower, of the class having a pair of vertically spaced parallel shafts (20, 22) which are rotated in synchronization with each other by a pair of meshing gears (36, 38) and are provided with bearings (28, 30) and oil seals (40, 42) requiring lubrication. The rotary machine includes an enclosed gear chamber (70) serving to form an oil sump (74) for lubrication of the meshing gears. The lubricating mechanism is intended to lubricate the oil seal (40) and bearing (28) of the upper shaft (20) of the machine located above and remote from the oil sump. The lubricating mechanism comprises a guiding mechanism (80, 82) for positively guiding the lubricant in the oil sump (74) to be entrained in sequence by the lower gear (38) and the upper gear (36) and lifting the lubricant to the upper region of the gear chamber (70).

Abstract: A by-pass control system for an internal combustion engine provided with a mechanical supercharger arranged in an intake pipe of the engine. The supercharger is connected to a crankshaft by means of a clutch operated in accordance with the engine load as well as the engine speed. A by-pass is arranged so as to by-pass the supercharger, on which by-pass a by-pass control valve is arranged. The by-pass control valve is operated in accordance with the engine speed, so that it is opened during an engine low load and high speed condition. The supercharger is located downstream of the throttle valve, while the by-pass is, on its downstream end, connected to the intake pipe downstream of the throttle valve and upstream of the supercharger.

Abstract: A by-pass control system for an internal combustion engine provided with a mechanical supercharger arranged in an intake pipe of the engine. The supercharger is connected to a crankshaft by means of a clutch operated in accordance with the engine load as well as the engine speed. A system is provided for maintaining the clutch disengaged irrespective of the engine load and engine speed when the engine is cranking. The load applied to a starter is decreased during the cranking operating due to the positive disconnection of the supercharger from the crankshaft, so that the engine can be easily started.

Abstract: A device for controlling the supply of secondary air in an internal combustion engine, having a secondary air control valve and a reed valve provided in the secondary air supply path and having a control circuit for receiving the output signal of an O.sub.2 sensor and producing a control signal for air-bleeding control valves of a carburetor for the engine. The secondary air control valve is controlled in accordance with the opening degree of a throttle valve of the carburetor.

Abstract: A method for controlling intake flow of an internal combustion engine having an intake port including a helical passage and a straight passage both extending towards a common port end opening which opens to the combustion chamber of the engine, in such a manner that a minimum proportion of intake flow is directed through the straight passage during idling operation of the engine regardless of the temperature condition of the engine, a maximum proportion of intake flow is directed through the straight passage during loaded operation at any non idling load of the engine when the engine is not warmed up, and a proportion of intake flow increasing according to the level of engine load is directed through the straight passage during loaded operation of the engine when the engine has been warmed up. This method is performed by an intake passage switchover control valve system operated conveniently by utilizing intake vacuum under a proper switchover thereof which itself incorporates the engine load performance.

Abstract: A fuel evaporation gas treating device arranged such that when a vehicle engine is operated a heat-sensitive means detects the temperature around the engine and the fuel system and the like, and if the temperature is within a proper temperature range, a changeover valve allows a carburetor bore and a canister to communicate with each other so that a fuel evaporation gas in the canister is introduced into the carburetor bore and burned through reduction, and on the other hand, when the detected temperature is higher or lower than the optimum value, the changeover valve causes the canister and the carburetor bore to be shut off from each other as well as allows the canister and the atmospheric air vent to communicate with each other so that the secondary air is introduced into the carburetor bore, thereby to make it possible to automatically control the introduction of the evaporation gas and the secondary air into the carburetor bore.

Abstract: An altitude compensation device for a carburetor including a chamber in communication with the atmosphere, an air bleed port conducting atmosphere from the chamber, a primary conduit providing fluid communication between the chamber and the fuel system of the carburetor, a first valve responsive to changes in atmospheric pressure for opening and closing the air bleed port, a first flow restrictor in the primary conduit downstream of the air bleed port, an auxiliary conduit providing fluid communication between an atmospheric pressure source and the primary conduit at a junction downstream of the flow restrictor and upstream of the carburetor fuel system, a second valve responsive to changes in atmospheric pressure controlling communication between the auxiliary conduit and the atmospheric pressure source, a second flow restrictor in the auxiliary conduit downstream of the atmospheric pressure source and upstream of the junction with the primary conduit, and a thermosensitive valve responsive to engine tempera

Abstract: A carburetor choke opening device wherein an altitude compensator opens an additional passage containing a delay element to vacuum at high altitudes so as to increase the amount of vacuum applied to the choke valve opening device at high altitudes, to insure that the choke valve continues to be opened without undue delay at high altitudes.