Nissan Motor Company Limited

Hiroshi Kuriki

Atsushi Iochi

Yutaka Kawamoto

Kenichi Goto

Shinsuke Nakazawa

Toshio Takahata

Hidefumi Komuro

Kenichi Gotoh

Nobuyuki Tokuou

An intake port structure includes a collector passageway disposed in an upstream section and the first and second branching passageways disposed in a downstream section that branch from the collector passageway. The intake port structure further includes an intake air flow impact section formed on a crotch portion between first and second branching passageways against which a portion of an intake air flow from the collector passageway collides such that the portion of the intake air flow is dispersed laterally toward both sides of the intake air flow impact section. The intake air flow impact section is recessed to stem portions of intake valves, and includes first and second impact surfaces. The second impact surface is formed along the stem portions of the intake valves. A fuel spray from a fuel injector is atomized when mixed with the dispersed intake air flow in the first and second branching passageways.

Intake port structure for internal combustion engine

Fuel vapor is produced in a fuel tank and absorbed in a canister. The absorbed fuel vapor is purged through a purge passage into an engine induction passage under predetermined engine operating conditions. A purge valve is provided in the purge passage to regulate the supply of gaseous mixture, including the absorbed fuel vapor, into the engine. A purge rate factor is determined corresponding to the concentration of evaporated fuel in the gaseous mixture. The concentration is determined utilizing the temperature of the fuel in the fuel tank.

Air/fuel ratio control apparatus

Fuel vapor is produced in a fuel tank and absorbed in a canister. The absorbed fuel vapor is purged through a purge passage into an engine induction passage under predetermined engine operating conditions. The air/fuel ratio is learned for air/fuel ratio feedback control. The learning control is inhibited when the fuel temperature exceeds a reference value during the air/fuel ratio feedback control. In another aspect of the invention, a purge valve is provided in the purge passage. The air/fuel ratio correction factor is set at an initial value in response to a movement of a purge valve from its open position toward its closed position.

A function diagnosing apparatus of an evaporative emission control system for an automotive vehicle executes a diagnosis when a diagnosis starting condition is satisfied. First, a purge cut valve and a vent cut valve are closed, and a bypass valve for a one way valve disposed between a fuel tank and a canister is opened. When a pressure in a purging line is not raised up by these valve operations, it is decided that the system goes wrong due to one of of the bypass valve in a cold condition, fuel vapor leakage, of the vent cut valve in an open condition, and/or no vapor existence. Upon opening the vent cut valve, it is decided as to whether the purge line pressure is dropped or not. When the purge line pressure is dropped, it is decided that the vent cut valve is normal. When the purge line pressure is not dropped, it is decided that vent cut valve is sticking closed.

Function diagnosis apparatus for evaporative emission control system

A first passage provided with a first valve for guiding vaporized fuel from a fuel tank into a canister, and a second passage provided with a second valve connecting this canister with an intake pipe downstream or a throttle, are provided. A pressure detecting mechanism is provided between this first valve and second valve, and a third valve is provided for leading fresh air into the canister. When the engine running condition satisfies a predetermined positive pressure test condition, the second and third valves are closed and the first valve is opened. In this state, the presence or absence of a leak is determined from the pressure detected by the pressure detecting mechanism. In other words, it is determined for example that the fuel tank has no leak if the pressure rises above a predetermined value.

Growing community of inventors

Yokohama, Japan

Hiroshi Kuriki