Toyota Jidosha Kabushiki Kaisha

Katsuhiko Teraoka

Takayuki Otsuka

Tatsumasa Sugiyama

Nobuyuki Kobayashi

Kuniaki Niimi

Kouichi Osawa

Yuji Takeda

Masahiko Teraoka

Koji Okawa

Susumu Shinohara

Takanori Tsukamoto

Akinori Ichikawa

Masashi Miyamaru

Hiroshi Ozaki

In an internal combustion engine to which an air pressure actuation mechanism such as a variable vibration isolating support device is installed side by side, the engine speed at the time of idling is made to suitably converge on the target idling speed. The idling speed control device includes: an idling speed control mechanism for controlling the intake air amount of the internal combustion engine to make the engine speed be the desired target idling speed at the time of idling of the internal combustion engine; an air pressure actuation mechanism operated by selectively introducing the atmospheric pressure and the intake tube negative pressure produced in the intake passage on the down stream side of the throttle valve; and an intake air amount compensating mechanism for compensating the adjusting position of the idling speed control mechanism in the direction of decreasing the intake air amount of the internal combustion engine when introducing the intake tube negative pressure after the introduction of the atmospheric pressure into the air pressure actuation mechanism.

Idling speed control device of internal combustion engine and variable

An apparatus for treating fuel vapor from a fuel tank. The apparatus includes a canister for collecting the fuel vapor generated in the fuel tank through a vapor line, a purge line for purging the collected fuel in the canister into an intake passage, and a control valve disposed midway on the purge line. The fuel tank, the canister, the vapor line and the purge line are connectable to one another to define a closed space. A testing device, which is separately provided from the apparatus, tests the sealing of the closed space after the pressure for the testing is introduced into the closed space from the testing device. The apparatus includes an atmospheric valve for connecting the canister with the atmosphere. The atmospheric valve has a diaphragm and a first and a second pressure chambers. The pressure in the canister is introduced into the first pressure chamber. The second pressure chamber has a first pressure port. The purge line has a second pressure port defined between the canister and the control valve. A pipe connects the first pressure port with the second pressure port. The pipe has a single introduction port. The introduction port communicates with the atmosphere when the test is not performed and is connected to the testing device when the test is performed. A check valve is located in the pipe between the introduction port and the second pressure port. The check valve allows the pressure for the testing introduced from the introduction port to be supplied to the second pressure port and prevents the pressure acting on the second pressure port from being released through the introduction port.

Fuel-vapor treating apparatus

The fault diagnostic apparatus of the present invention detects a failure (a leak) of a fuel tank of an engine. In this invention, space above the fuel level in the fuel tank is connected to a canister. The canister contains an adsorbent to adsorb evaporated fuel in the tank to prevent the evaporated fuel from being released to the atmosphere. Valves are provided to the canister to keep the internal pressure of the canister within a predetermined range. A control circuit of the engine employs a pressure sensor to monitor the internal pressure of the fuel tank, and determines whether the fuel tank has failed in accordance with a change in the internal pressure of the fuel tank. Since the change in the fuel level in the fuel tank varies in accordance with the fuel consumption rate, the change in the pressure in the fuel tank also varies in accordance with the fuel consumption rate. Therefore, the control circuit stops the determining operation when the fuel consumption rate of the engine is too large or too small, to avoid an error in the diagnosis of the fuel tank.

Fault diagnostic apparatus for evaporated fuel purging system

In a diagnostic apparatus for an evaporative fuel purge system having a canister receiving fuel from a fuel tank via a vapor passage, the fuel being supplied to an intake air passage of an internal combustion engine via a purge passage from the canister, a pressure detecting unit detects a pressure in the evaporative fuel purge system. A decision making unit determines whether or not a failure has occurred in the evaporative fuel purge system on the basis of a relationship between the pressure detected by the pressure detecting unit and a decision value. A correction unit corrects the relationship on the basis of a value of a parameter having an influence on the pressure detected by the pressure detecting unit.

Diagnostic apparatus for evaporative fuel purge system

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

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Toyota, Japan

Katsuhiko Teraoka