Toyota Jidosha Kabushiki Kaisha

Nippondenso Co., Ltd.

Toyoda Jidosha Kabushiki Kaisha

Koji Okawa

Mitsuru Takada

Nobuyuki Kobayashi

Akinori Osanai

Kazuhiko Norota

Shinichi Hoshino

Toru Kidokoro

Takaaki Itou

Yoshihiko Hyodo

Toshinari Nagai

Hiroshi Kanai

Takashi Ishikawa

Hiroyuki Mizuno

Takayuki Otsuka

Kenji Harima

Kouichi Osawa

Shinsuke Kiyomiya

Tatsumasa Sugiyama

Katsuhiko Kodama

Tatsunori Kato

Shuji Yuda

Katsuhiko Teraoka

Kazuhiko Iwano

Disclosed is a fuel vapor treating apparatus, in which fuel vapor evaporated in a fuel tank is not released directly into the atmosphere but is collected and treated. This apparatus is provided with a canister for collecting fuel vapor and a purge line for purging the fuel vapor collected in the canister to an intake passage of an engine. The canister has a first control valve for controlling introduction of fuel vapor thereto. The canister also has a second control valve for controlling the introduction of outside air and the exhaust of gas therefrom. The first control valve communicates with a vapor line extending from the fuel tank and is opened whenever the internal pressure of the fuel tank exceeds a predetermined level to introduce fuel vapor from the fuel tank into the canister. The second control valve is designed to communicate with the atmosphere and is opened whenever fuel is purged through the purge line to the intake passage to introduce outside air into the canister. The second control valve is opened whenever the internal pressure of the canister exceeds a predetermined level to exhaust fuel-free gas left after collection of the fuel. Both the first control valve and the second control valve are diaphragm check valves. The control valves are designed to be readily detached from the canister.

Fuel vapor treating apparatus

An air-fuel control system for an internal combustion engine is provided in which air-fuel ratio control system a deviation effect due to an amount of evaporated fuel distributed to each cylinder group differing from cylinder group to cylinder group is eliminated when a deviation of air-fuel ratio due to aging of the engine has been learned. A difference value between the air-fuel correction factor and a value of a range of distribution deviation of the air-fuel ratio is obtained so that the difference value is used as the air-fuel correction factor. The difference value is obtained when the engine is determined to be in a purging operation by the first determining means, and when it is determined that learning of the air-fuel ratio correction factor is not completed. The difference value represents a true deviation of the air-fuel ratio due to aging of the engine parts.

Air-fuel ratio control system for an internal combustion engine

An air-fuel ratio control apparatus includes: a determining part for determining a target purge ratio in accordance with operating conditions of an engine; a purge control part for controlling a flow rate of evaporated fuel, supplied from an evaporated fuel purge system into an intake passage of the engine, by actuating a purge control valve based on the target purge ratio, and for storing an evaporated fuel flow rate of the purge control valve; a fuel injection control part for generating a drive signal in accordance with a fuel injection time, and for controlling an air-fuel ratio of an air-fuel mixture to the intake passage by actuating a fuel injection valve in accordance with the drive signal; an estimating part for estimating the ratio of an evaporated fuel flow rate to an intake air flow rate based on sensed operating conditions of the engine and on the stored evaporated fuel flow rate of the purge control part; and a fuel injection time determining part for determining a fuel injection time based on the estimated ratio, and for supplying the fuel injection time to the fuel injection control part.

Apparatus for controlling air-fuel ratio of air-fuel mixture to an

An air-fuel ratio control system for an internal combustion engine which includes an evaporative fuel purge system having a canister for temporarily storing fuel vapor, detects an air to fuel ratio in the exhaust gas from the engine. An air-fuel ratio controller controls the air-fuel ratio in exhaust gas from the engine by varying a fuel quantity supplied to the engine so that the air-fuel ratio approaches a predetermined target air-fuel ratio. The evaporated fuel is purged from the canister at a specific purging rate determined based on engine operating conditions. An air-fuel ratio-shift is controlled based on the derivation of an amount by which the air-fuel ratio has shifted from the target air-fuel ratio due to a cause independent of the purging operation. The first amount, which is relatively constant over time in comparison to a second amount of air-fuel ratio shift occurring as a result of the purging operation, is derived based on a first detected air-fuel ratio-shift amount when the purge system is purging at a first purging rate. The second air-fuel ratio-shift amount is detected when the purge system is purging at a second purging rate different from the first purging rate.

Air-fuel ratio control system for internal combustion engine having

An air-fuel ratio control apparatus constructed, in an engine of a type storing evaporated fuel generated in a fuel tank in a canister and thereafter drawing off the evaporated fuel to an intake side of an engine through a bleedoff passage, so as to inhibit renewal of an air-fuel ratio learning value when the evaporated fuel concentration is at a predetermined value or higher in case of learning and renewal of an air-fuel ratio in order to make feedback control of the air-fuel ratio of an air-fuel mixture supplied to the engine. In an apparatus which adsorbs evaporated fuel generated in a fuel tank in a canister and purges the evaporated fuel adsorbed in the canister to an intake side of an internal combustion engine together with air through a purge valve, an air-fuel ratio learning value is renewed in accordance with a deviation between an air-fuel ratio feedback FAF value detected by an oxygen sensor and a FAFSM value obtained by smoothing the FAF value with a large smoothing constant. Further, renewal of the air-fuel ratio learning value is inhibited when the concentration of the evaporated fuel is high, and renewal of the air-fuel ratio learning value is executed even during purge execution by the purge valve when the concentration is low.

Air-fuel ratio control apparatus for internal combustion engine

An evaporated fuel purge control apparatus includes a purge control valve arranged in a purge passage between a canister and an intake passage of an engine, the purge control valve being switched on and off in accordance with a control factor, the control factor indicating a duty ratio of an on-time of the purge control valve within a duty cycle to a total duty-cycle time, a detecting part for detecting an operating condition under which the engine is operating, and a flow rate control part for setting a control factor for the purge control valve in accordance with the operating condition detected by the detecting part, the control factor set by the flow rate control part allowing a flow rate of evaporated fuel fed from the canister into the intake passage through the purge control valve to be maintained at a constant level when the operating condition of the engine changes.

Apparatus for controlling a flow of evaporated fuel from a canister to

A malfunction detecting apparatus for an evaporated fuel purge system includes a first control valve for controlling a flow of fuel vapor in a purge passage between a canister and an intake passage, a second control valve for controlling a flow of air from the atmosphere to the canister via an air inlet opening of the canister, a first control part for turning OFF the second control valve and for turning ON the first control valve during a first time period, so as to subject the purge passage, the canister, and a vapor passage to a negative pressure of the intake passage during the first time period, and a first discriminator for detecting whether or not a malfunction has occurred in the system, in accordance with a pressure change rate derived from pressures of the system sensed at a start of the first time period and at an end thereof. The apparatus further includes a second control part for detecting whether or not a pressure of the system reaches a prescribed negative pressure after it is detected that no malfunction has occurred in the system, and for turning OFF the first and second control valves during a second time period after the prescribed negative pressure is reached, and a second discriminator for detecting whether or not a malfunction has occurred in the system, in accordance with a pressure change rate derived from pressures of the system sensed at a start of the second time period and at an end thereof.

Apparatus for detecting malfunction in evaporated fuel purge system used

An evaporative fuel control apparatus of an internal combustion engine is provided with a purge correction prohibition part. The apparatus includes a detection part for detecting operating conditions of the internal combustion engine and for supplying signals indicative of the operating conditions, a purge control valve for controlling a flow of fuel vapor to an intake passage of the engine, a calculation part for calculating a fuel injection amount in response to the signals, and a fuel injection control part for varying a feedback correction factor of an air-fuel ratio in response to the signals so as to maintain the air-fuel ratio at a stoichiometric value and for correcting the fuel injection amount on the basis of the feedback correction factor. The apparatus also includes a purge correction part for correcting a purging amount of fuel vapor which is fed into the intake passage, in response to the feedback correction factor, so that the feedback correction factor is adjusted to be within a predetermined range, and a prohibition part for preventing the purge correction part from adjusting the purging amount of fuel vapor when the feedback correction factor is not within the predetermined range and it is determined in response to the signals that the feedback correction factor changes from a value outside the range to a value within the range.

Evaporative fuel control apparatus of internal combustion engine

An evaporative fuel control apparatus of an internal combustion engine for controlling a purge correction amount and a fuel injection amount in response to a concentration of fuel vapor in intake mixture. The apparatus includes a detection part for detecting operating conditions of the engine and for supplying signals indicative of the operating conditions, a purge valve for controlling a flow of fuel vapor from a fuel tank to an intake passage, and a calculation part for calculating the fuel injection amount in response to the signals. The apparatus also includes a first injection control part for varying a feedback correction factor of an air-fuel ratio in response to the signals so as to maintain the air-fuel ratio at a stoichiometric value, and for correcting the fuel injection amount with the feedback correction factor, a second injection control part for correcting the fuel injection amount in response to the fuel vapor concentration which is determined from the varied feedback correction factor, and a purge correction part for correcting a purging amount of fuel vapor being fed by the purge valve to the intake passage in response to the fuel vapor concentration.

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Toyota, Japan

Koji Okawa