Fuji Jukogyo Kabushiki Kaisha

Nissan Motor Company Limited

Hideo Yabuhara

Ichiro Kudo

Yoshiaki Ohara

Takemasa Yamada

Fujio Takimoto

A supercharging system has a turbocharger driven by exhaust-gas of the engine, a supercharger driven by an engine and communicated with the turbocharger and the engine in series. A clutch is provided in a device for driving the supercharger and a bypass having a control valve is provided around the supercharger. A control unit is provided to respond to engine operating conditions for operating the clutch and the control valve. The control unit operates to disengage the clutch at light load on the engine in a predetermined low engine speed range, to engage the clutch at heavy load in the low engine speed range, and to disengage the clutch in a predetermined high engine speed range. The control valve is gradually opened in accordance with variation of engine operation conditions when the engine operation is in a transient state.

Supercharging system for automotive engines

An air-fuel ratio control system for a vehicle powered by an internal combustion engine having an emission control system with a three-way catalytic converter for controlling the air-fuel ratio in accordance with the operation of the engine. A vacuum sensor detects heavy load operation of the engine, and an engine speed detecting circuit and a predetermined voltage supply circuit are provided. The engine speed detecting circuit is so arranged as to produce an output when the engine speed is lower than a predetermined value. A feedback control circuit is provided for controlling the air-fuel ratio to the stoichiometric air-fuel ratio in normal operating conditions. A first switch device is actuated by the output of the vacuum sensor to connect the output of the predetermined voltage supply circuit with the input of the feedback control circuit when heavy load operation is detected and to render the feedback control circuit inoperative. A second switch is to be actuated by the output of the engine speed detecting circuit to stop the control of the air-fuel ratio for supplying a rich air-fuel mixture by the carburetor to the engine.

Air-fuel ratio control system for an internal combustion engine

An air-fuel ratio control system for an internal combustion engine having an O.sub.2 -sensor for detecting the concentration of oxygen of exhaust gases passing through the exhaust passage, an electromagnetic valve for correcting the air-fuel ratio of the air-fuel mixture supplied by a carburetor, a feedback control circuit comprising a judging circuit for judging an output signal of the O.sub.2 -sensor and a driving circuit for driving the electromagnetic valve in dependency on an output signal of the judging circuit for controlling the air-fuel ratio to a value approximately to the stoichiometric air-fuel ratio. A Maximum and minimum value hold circuits respectively hold a maximum and a minimum value in one cycle of output variation of the detector. A first comparator compares the outputs of both hold circuits. A second comparator compares the output of the O.sub.2 -sensor with a predetermined level. A gate circuit is responsive to the output signals of the comparators for producing gate control signals. Switch circuits connect the O.sub.2 -sensor to the judging circuit. The gate circuit and the switch circuits operate such that when the output of the second comparator is high representing an output of the O.sub.2 -sensor is higher than the predetermined level, or when the output of the second comparator is low and the output of the first comparator means is high, the output of the O.sub.2 -sensor is connected to the judging circuit for performing the feedback control irrespective of the level of the detected air-fuel ratio, but when the outputs of both comparators are low, the fixed voltage supply source is connected to the judging circuit.

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Musashino, Japan

Hideo Yabuhara