Abstract: An evaporative fuel control system for internal combustion engine which comprises a canister for storing a fuel vapor, a purge passage connecting the canister to an intake manifold, a valve provided in the purge passage, an engine temperature sensor for sensing an engine temperature, a fuel distillation sensor for sensing a fuel distillation characteristic of a fuel within a fuel tank, a first valve control part for controlling a valve opening position of the valve responsive to an engine temperature signal supplied from the engine temperature sensor, and a second valve control part for controlling a time to turn the valve on responsive to a fuel distillation signal supplied from the fuel distillation sensor.

Abstract: An exhaust gas recirculation system which comprises a passage provided between an exhaust passage of an internal combustion engine and an intake passage thereof, a valve provided at an intermediate portion of the passage for regulating a flow of an exhaust gas recirculated through the passage, a fuel distillation part for sensing a fuel distillation characteristic of a fuel within a fuel tank, an engine temperature part for sensing an engine temperature of the internal combustion engine, a first valve control part, and a second valve control part. The first valve control part generates a reference value at which the valve is turned ON allowing the exhaust gas recirculation to the intake passage, the reference value being varied to a first level when the fuel is a heavy type fuel and varied to a second level when the fuel is a light type fuel, the first level being higher than the second level.

Abstract: Disclosed is an exhaust gas recirculation system of an internal combustion engine for high altitude use. The system includes a feedback control valve for controlling the amount of exhaust gas fed back to an intake passage, and a compensating device for decreasing a set pressure level of the feedback control valve, above which set level the feedback control valve is caused to open so as to feed back the exhaust gas, when the atmospheric pressure level is lowered to less than a predetermined level. Thus, the amount of NO.sub.x formation contained in the exhaust gas can always be maintained at a low level and, furthermore, good operating characteristics of the engine can be obtained even when the engine is operated at high altitudes.

Abstract: Disclosed is an exhaust gas recirculation engine for high altitude use. The engine comprises an exhaust gas recirculation control valve device communicating an intake manifold with an exhaust manifold for circulating a part of the exhaust gas for reducing harmful NO.sub.x contaminants contained in the exhaust gas, which device is actuated by vacuum supplied from a vacuum port disposed at a position adjacent to a throttle valve of a carburetor, a reservoir tank for storing a vacuum; a control valve device for controlling the delivery of the vacuum from the reservoir tank; and an altitude compensating device for actuating the control valve device in accordance with the altitude.Utilizing the above-described engine, exhaust gas is recirculated for a predetermined interval of time after the throttle valve has been opened at a level which is more than the predetermined level during high altitudes.

Abstract: Disclosed is an air bleed type carburetor for supplying an air fuel mixture to an engine, which carburetor comprises a high altitude control system and a low altitude control system, each system being provided with a control valve device for controlling a bleed air flow to a main jet of the carburetor, and an altitude compensating device for selectively switching the high altitude control system and the low altitude control system in accordance with changes in altitude. The carburetor can supply a desirable air fuel ratio in accordance with changes in altitude and with changes in the operating characteristics of the engine.