Toyota Jidosha Kogyo Kabushiki Kaisha

Nippon Soken, Inc.

Nippondenso Co., Ltd.

Akira Takata

Tadashi Hattori

Tamotsu Fukuda

Takamichi Nakase

Hitoshi Yoshida

Toshio Tanahashi

Kenji Yamada

Akira Ii

Toshio Oda

Katsuhiko Ohiwa

Kenichi Akutagawa

Keichi Akutagawa

An intake system for an internal combustion engine comprises a throttling system mounted in an intake pipe between a fuel injection valve and an intake manifold, the throttling system including a stationary valve body fixed in the intake pipe in opposition to the injection valve and a hollow valve body mounted in the intake pipe movably in an axial direction of the intake pipe. The hollow valve body has a downwardly converged inner wall surface surrounding the stationary valve body to define therebetween valve opening of variable opening area. The axial movement of the hollow valve body causes the change in the opening area of the valve opening to control an amount of air-fuel mixture charged therethrough into the engine.

Air-fuel intake system for an internal combustion engine

An intake system for internal combustion engines comprises a throttling system mounted in an intake pipe between a fuel injection valve and an intake manifold, the throttling system including a stationary valve body fixed in the intake pipe in opposed relation with the injection valve and a hollow valve body mounted in the intake pipe for movement in the axial direction of the intake pipe. The hollow valve body has a downwardly converged inner wall surface surrounding the stationary valve body to define therebetween valve opening of variable opening area. The stationary valve body includes a frusto-conical portion and a cylindrical portion, of which lower edge is in the form of sinusoidal wave to cooperate with the hollow valve body in producing the valve opening of gradually increasing opening area.

Air-fuel intake system for internal combustion engines

An air flow amount adjusting system produces an air-fuel mixture of a desirable air-fuel ratio by controlling the direction of movement of a bypass valve mounted in an additional air supply pipe adapted to supply additional air into either the intake system or exhaust system of an internal combustion engine in accordance with an output signal produced from a gas sensor mounted in the exhaust system of the engine and indicative of the air-fuel ratio of the mixture supplied to the engine. A two-level mode signal whose threshold corresponds to the desired air-fuel ratio is produced in accordance with the output signal of the gas detector. After the two-level mode signal has changed from one level to the other level, the movement of the bypass valve is stopped for a certain period of time. If desired, the stopping period of the bypass valve may be changed in accordance with the temperature of the engine.

Air flow amount adjusting system for an internal combustion engine

An altitude compensation device for an internal combustion engine having a vacuum-operated ignition timing advancer and a carburetor has an atmospheric pressure variation responsive valve operative to control the air bleed of the carburetor and the vacuum fed to the vacuum advancer such that, as the atmospheric air pressure is lowered due to increase of the altitude, the air flow into the advancer vacuum chamber is decreased to advance the ignition timing while the air flow into the carburetor air bleed passage is increased to increase the air-fuel ratio of the air-fuel mixture produced by the carburetor.

Internal combustion engine with altitude compensation device

Additional air is supplied through an additional air passage having a bypass valve into the main air passage of an internal combustion engine downstream of the throttle valve, and the amount of the additional air is controlled in accordance with the opening of the bypass valve. The direction of rotation of a bypass valve driving pulse motor is controlled in accordance with the output signal of an air-fuel mixture ratio sensor mounted in the exhaust system of the engine. Also the rotational speed of the pulse motor is varied in accordance with the operating conditions of the engine during warm-up operation.

Air-fuel ratio adjusting system

An additional air supply system for adjusting the air-fuel ratio of a mixture includes the improved control unit for actuating, at two different speeds, a drive motor of a bypass valve disposed in an additional air supply path. The control unit is provided with an air-fuel ratio discriminating circuit for generating high and low level signals by comparing a detected air-fuel ratio with the stoichiometric ratio, and an actuating circuit for producing pulse signals at each instant of inversion of the signal levels of the air-fuel ratio discriminating circuit in such that for a predetermined period from the instant of inversion a high frequency pulse signal is produced and then a low frequency pulse signal is produced for the remaining period until the next inversion. Since the pusle signals having two different frequencies are applied to the drive motor of the bypass valve, the bypass valve is drived at a fast speed to a predetermined amount of opening or closing and then moved slowly until the next inversion of the signal level.

Additional air supply system for an internal combustion engine

An apparatus for controlling the air-fuel ratio of an air-fuel mixture to be supplied into a combustion chamber of an internal combustion engine comprises a passage bypassing a carburetor and a throttle valve of the engine for supplying an additional air into the engine intake duct downstream of the throttle valve to dilute the air-fuel mixture to an air-fuel ratio most suited for the engine operation. An air valve is provided in the bypass passage to vary the air-flow cross-sectional area of the passage. The opening of the air valve is controlled mainly in accordance with the air-fuel ratio of the mixture as detected by an air-fuel ratio detector in the path of flow of engine exhaust gases. A variable orifice is provided in the bypass passage downstream of the air valve and defined by a valve seat and a needle valve operatively associated therewith to vary the opening area of the orifice. The needle valve is actuated by a pneumatic valve actuator which is responsive to variations in the engine manifold vacuum. The arrangement is such that the pressure difference across the air valve is kept substantially constant whereby the supply of the additional air is substantially in proportion to the engine intake air and free from influence by the engine manifold vacuum.

Air-fuel ratio controlling apparatus for an internal combustion engine

An automatic choke having a casing, a cover, and a spiral bimetal element disposed in a chamber defined by the casing and the cover and connected at its one end with the cover and at the other end with a choke valve shaft rotatably supported by the casing, wherein the cover is mounted to the casing by a mounting means which permits rotational adjustment of the cover relative to the casing, while a positioning means such as a pin and a socket is provided between the casing and the cover in its initial assembly, the positioning means permitting normal mounting of the cover to the casing only when the cover is in a predetermined rotational position relative to the casing.

Tamperproof automatic choke

In an air flow control system including a gas sensor for detecting the concentration of a constituent of the exhaust gases from an internal combustion engine, an air passage for supplying additional air into the intake system or exhaust system of the engine, a by-pass valve for varying the passage area of the additional air passage, and means for controlling the opening and closing of the by-pass valve in accordance with the detection signal from the gas sensor whereby the amount of additional air supplied into the intake system or exhaust system of the engine is controlled in accordance with the concentration of the constituent of the exhaust gases, there is further provided an acceleration/deceleration sensor for detecting acceleration or deceleration of the engine, whereby when a transition from the acceleration or deceleration operating condition to the steady-state operating condition is detected, the opening and closing control of the by-pass valve is accomplished in such a manner that the amount of opening and closing movement of the by-pass valve is gradually decreased. Thus, when the engine comes into the steady-state operation from the transient operation, the rate of change in the opening of the by-pass valve is gradually decreased to reduce variation of the air-fuel ratio upon the transition from the acceleration/deceleration operation to the constant speed operation.

Air flow control system

An air-fuel ratio controlling system for an internal combustion engine including a control circuit for controlling, in accordance with a detected air-fuel ratio, the operation of a drive motor of a control valve mounted in an additional air supply passage. The control circuit includes a timing pulse generator for generating timing pulses synchronized with a running speed of the engine and thus the control valve is intermittently rotated by a predetermined amount in response to the timing pulses. By increasing the frequency of the timing pulses during the periods of rapid acceleration and deceleration, a response to the change in the engine speed is further improved.

Air-fuel ratio controlling system

An air-fuel ratio adjusting system controls the amount of additional air supply through the bypass passage of the carburetor to ensure optimum engine operation even in a warming up condition of the engine. The air-fuel ratio adjusting system includes an air-fuel ratio sensor disposed in the exhaust manifold, a warm-up sensor for detecting the temperature of engine cooling water or engine block, and a control unit for providing a control signal to a driving motor for the bypass valve. The bypass valve is controlled so that the air-fuel ratio of the mixture becomes the stoichiometric one and at the same time, during the warming up condition, the maximum opening of the bypass valve is limited to a predetermined degree depending on the temperature of the engine.

Air-fuel ratio adjusting system for internal combustion engines

An exhaust gas purifying device for an internal combustion engine, comprising a catalytic converter containing a three way catalyzer therein, a first oxygen sensor disposed in the exhaust passage, and an air-fuel ratio regulating means for regulating an air-fuel ratio of the mixture fed into the cylinder of the engine so as to conform it to the stoichiometric air-fuel ratio in response to an output signal of said first oxygen sensor over a larger range of running conditions of a vehicle. Said exhaust gas purifying device further comprises a second oxygen sensor located downstream of the catalytic converter, and a secondary air feeding device located upstream of the catalytic converter for regulating the feeding of a secondary air into the exhaust gas in response to an output signal of said second oxygen sensor so that the ratio of the air consisting of said secondary air and air contained in the mixture introduced into the cylinders of the engine to the fuel contained in the mixture introduced into the cylinders is made equal to the stoichiometric air-fuel ratio at the time of acceleration, deceleration and gear-shifting.

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Toyota, Japan

Akira Takata