Toyota Jidosha Kabushiki Kaisha

Denso Corporation

Denson Corporation

Noriyuki Iden

Yoshihito Moriya

Kiyoshi Sugimoto

Shuichi Hanai

Tokiji Ito

Osamu Sato

Tadao Hasegawa

Yuichi Kohara

Shin Adachi

Jouji Yamaguchi

Shinitiro Kikuoka

Shinichiro Kikuoka

Tokiji Itoh

Nobuhiko Sugie

A failure test apparatus for a fuel-vapor purging system for adsorbing fuel vapor in a fuel tank into a canister and for purging fuel to an intake system of an internal combustion engine as needed. The purging system has at least one valve. A first test unit provides a differential pressure between the inside and the outside of the fuel-vapor purging system, measures the internal pressure with the fuel-vapor purging system in an airtight condition, and determines whether a leak exists in the fuel-vapor purging system from the behavior of the internal pressure. The test by the first test unit involves a differential-pressure forming process of creating a differential pressure between the inside and the outside of the fuel-vapor purging system, a sealing process of making the fuel-vapor purging system airtight when the differential pressure exists, and a differential-pressure releasing process for releasing the differential pressure. In association with one or more of the processes, a second test unit measures the internal pressure of the fuel-vapor purging system to detect a failure in any valve actuated in one of the processes based on the behavior of the internal pressure.

Failure test apparatus for fuel-vapor purging system

In a diagnostic apparatus and method for a fuel vapor purge system in which fuel vapor generated in a fuel tank trapped in a chamber is purged into an intake passage of an internal combustion engine through a purge path, a first change in a pressure of the purge path is measured after creating a pressure difference between the inside and outside of the purge path and sealing the purge path, and a second change in pressure that varies with an amount of fuel vapor generated in the fuel tank is measured while the purge path is sealed for a first period of time after an atmospheric pressure is introduced into the purge path. Then, it is determined whether leakage is present in the purge path, based on the first change and the second change in the pressure of the purge path. Before the measurement of the first and second pressure changes, a third change in the pressure that varies with an amount of fuel vapor generated in the fuel tank is measured while the purge path is sealed for a second period of time after the atmospheric pressure is introduced into the purge path before the pressure difference is created. The leakage diagnosis is inhibited when the third change in the internal pressure is greater than a predetermined value, and the leakage diagnosis is permitted when the third change is equal to or less than the predetermined value.

Diagnostic apparatus and method for fuel vapor purge system

An improved diagnosis apparatus for detecting leakage of a fuel vapor purge system that purges fuel vapor from a fuel tank to an intake passage of an engine. The apparatus includes a pressure sensor and a purge valve. The pressure sensor detects the pressure in the purge system. The purge valve connects the purge system with the intake passage for lowering the purge system pressure to a predetermined pressure level. After the purge system pressure is lowered to the predetermined level, the purge system is sealed. The apparatus measures the rate of pressure change immediately after the purge system is sealed. The apparatus subsequently measures the rate of pressure change when the purge system pressure reaches a second reference pressure value and computes the ratio of the rates. The apparatus diagnoses whether there is a leak in the purge system based on the ratio and the rate of pressure change at the second reference pressure value.

Diagnosis apparatus for fuel vapor purge system

A test apparatus for a fuel vapor purge system that performs frequent tests. The testing apparatus detects leakage of fuel vapor from a system passage by sealing the system passage and monitoring changes in the pressure. After the test, the apparatus applies atmospheric pressure to the system passage. Therefore, the pressure in the system passage is quickly restored to atmospheric pressure.

Fault detection apparatus and method for fuel vapor purge system

In a variable valve control device, the minimum operating hydraulic pressure necessary for controlling the vane rotor is arranged to be higher than that for axially moving the piston member. Thus, whenever the angular phase is actually changed, the hydraulic pressure sufficient enough to move the piston member may be always ready to be applied to the axial movement control member. Therefore, when the intake camshaft is at the lowest lift stroke position, the intake camshaft may be easily shifted from the lowest lift stroke position to the higher lift stroke position without time delay so that a highly accurate angular phase control of the intake camshaft relative to the timing pulley may be secured.

Variable valve control device

A valve driving apparatus for an internal combustion engine. Each combustion chamber has a pair of intake ports and a pair of intake valves for selectively opening and closing the intake ports. Each intake valve is driven with a variable amount of valve lift. The apparatus includes a camshaft rotatably supported by the engine, cams, cam followers, a shaft moving mechanism, and brackets. Each cam lifts an associated intake valve in response to rotation of the camshaft. Each cam has a cam nose for lifting a corresponding intake valve. The radius of the cam nose varies in the axial direction. Cam followers transmit movement of the intake cams to the intake valves. The shaft moving mechanism moves the cams relative to the valves in an axial direction of the camshaft thereby varying the amount of valve lift. A lifter structure is provided that is circularly shaped to improve manufacturing accuracy. In another embodiment, the valves are oriented to increase the amount of axial movement that the cam can make, which results in greater optimization of the air intake amount.

Valve driving apparatus for engine

A variable valve control apparatus which is capable of reducing the size of the entire apparatus. A rotary member is assembled with a timing pulley by a bolt so that it rotates together with the timing pulley. A cylinder head supports the rotary member rotatably but axially immovably. The rotary member supports an intake camshaft rotatably and axially movably. Even if the intake camshaft is axially moved and changed in rotational phase relative to the timing pulley as arc-shaped gears move axially, the rotational phase between an exhaust camshaft and the timing pulley does not change.

Variable valve control apparatus

Each of a positive spline member and a negative spline member is engaged through a spline engagement with a vane rotor. Both the positive spline member and the negative spline member are securely fixed to a cam shaft by means of a bolt. The cam shaft causes an axial reciprocative movement relative to the vane rotor. Each external spline formed on the positive spline member is brought into contact at its trailing side with an internal spline of the vane rotor. Each external spline formed on the negative spline member is brought into contact at its leading side with an internal spline of the vane rotor. This arrangement eliminates any backlash formed between the internal splines of the vane rotor and the external splines of the positive and negative spline members.

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Toyota, Japan

Noriyuki Iden