Abstract: Disclosed herein is an evaporative emission control system which can prevent changes in fuel component in the fuel tank and vacuum boiling in the fuel pump to thereby accurately control the air-fuel ratio to a desired value and ensure smooth supply of the fuel. The control system includes an evaporative fuel passage for connecting a fuel tank and an intake system of an internal combustion engine, and a control valve is provided in the evaporative fuel passage for opening and closing the evaporative fuel passage. It is determined whether or not a fuel temperature is higher than or equal to a predetermined fuel temperature. If the fuel temperature is higher than or equal to the predetermined fuel temperature, the opening operation of the control valve is disabled.

Abstract: Disclosed herein is an evaporative emission control system which can prevent changes in fuel component in the fuel tank and vacuum boiling in the fuel pump to thereby accurately control the air-fuel ratio to a desired value and ensure smooth supply of the fuel. The control system includes an evaporative fuel passage for connecting a fuel tank and an intake system of an internal combustion engine, and a control valve is provided in the evaporative fuel passage for opening and closing the evaporative fuel passage. It is determined whether or not a pressure in the tank is higher than or equal to a pressure value obtained by adding a pressure in the intake system. If the pressure in the tank is higher than or equal to the pressure value, the opening operation of the control valve is enabled.

Abstract: Disclosed herein is an evaporative emission control system which can properly control the ratio between a tank purge amount and a canister purge amount to realize quick pressure reduction in a fuel tank and ensuring the storage capacity of a canister in a well balanced fashion. A target pressure in controlling the pressure in the fuel tank at a negative pressure and a detected pressure in the fuel tank are compared with each other. When the difference between the target pressure and the detected pressure is large, tank purge is preferentially carried out to open a tank pressure control valve. When the detected pressure is in the vicinity of the target pressure, canister purge is preferentially carried out to purge the evaporative fuel stored in the canister.

Abstract: An abnormality diagnosis apparatus for an evaporative emission control system which includes a fuel tank, a canister for adsorbing evaporative fuel generated in the fuel tank, a charging passage for connecting the canister and the fuel tank, a purge passage for connecting the canister and an intake system of an internal combustion engine, a vent passage for opening the canister to atmospheric air, an evaporative fuel passage for connecting the fuel tank and the intake system, a first control valve interposed in the charging passage for opening and closing the charging passage, a second control valve interposed in the purge passage for opening and closing the purge passage, a third control valve interposed in the vent passage for opening and closing the vent passage, a fourth control valve interposed in the evaporative fuel passage for opening and closing the evaporative fuel passage, is disclosed.

Abstract: An actuator is connected to one of components forming a power transmitting device capable of transmitting a power provided by a valve operating cam provided on a cam shaft, so that the actuator can drive an engine valve in a lift amount which is obtained by addition of a lift amount of the engine valve based on a cam profile of the valve operating cam and a lift amount of the engine valve based on the operation of the actuator. Thus, a portion of the lift amount of the engine valve is borne by the valve operating cam, whereby a valve-opening power borne by the actuator can be reduced, as compared with a system designed so that the engine valve is driven by only the actuator only. The amount of electric power consumed by the actuator can be smaller.

Abstract: A valve operating system in an internal combustion engine is disclosed, wherein the operational characteristic of an engine valve which is an intake valve or an exhaust valve, can be changed in accordance with the operational state of the engine. In the valve operating system, a power transmitting means comprises an inner wheel, an outer wheel surrounding the inner wheel, and a carrier on which a planetary rotor is rotatably carried. The inner wheel is operatively connected to a cam shaft, and the outer wheel is connected to the engine valve. A rotational-amount control device is connected to the carrier for controlling the rotational amount of the carrier in accordance with the operational state of the engine. Thus, the size of the valve operating system can be reduced, and moreover, the operational characteristics of the engine valve can be finely changed.