Abstract: An evaporative fuel processing system adapted to be capable of detecting abnormality of an evaporative emission control system for storing, in a canister, evaporative fuel generated from a fuel tank for holding fuel to be supplied to an internal combustion engine, and purging evaporative fuel into the intake system of the engine. A first control valve is arranged across a passage extending between the fuel tank and the canister. A second control valve is arranged across a passage extending between the canister and the intake system of the engine. A third control valve is provided for an air inlet port of the canister communicatable with the atmosphere. Through operating these control valves to open and close them, the evaporative emission control system is negatively pressurized, and abnormality of this system is detected based on the pressure detected in this negatively pressurized state thereof. Timing for carrying out abnormality determination is determined depending on conditions of the fuel tank.

Abstract: An air intake noise suppressor for reducing noise generated by intake air sucked into an internal combustion engine. An intake pipe is provided with a resonance pipe, which extends forwards within the intake pipe as penetrating through a rear end wall of the intake pipe, communicates with the interior of the intake pipe through an opening at its front end, extends backwards from the rear end wall externally of the intake pipe and has its rear end closed, and the resonance pipe is fixedly locked to the intake pipe at its portion penetrating through the rear end wall and in the proximity of the opening at the front end. Since the resonance pipe is accommodated within the intake pipe over a considerable length and only its rear end portion projects backwards from the intake pipe, a surplus space is almost not necessitated for mounting the resonance pipe, and yet the resonance pipe itself can be made sufficiently long.

Abstract: An evaporative fuel processing system adapted to be capable of detecting abnormality of an evaporative emission control system for storing, in a canister, evaporative fuel from a fuel tank for holding fuel to be supplied to an internal combustion engine, and purging evaporative fuel into the intake system of the engine. A first control valve is arranged across a passage extending between the fuel tank and the canister. A second control valve is arranged across a passage extending between the canister and the intake system of the engine. A third control valve is provided for an air inlet part of the canister communicatable with the atmosphere. Through operating these control valves to open and close them, the evaporative emission control system is negatively pressurized, and abnormality of this system is detected based on the pressure detected in this negatively pressurized state thereof. Timing for carrying out abnormality determination is determined depending on conditions of the fuel tank.