Nippondenso Co., Ltd.

Toyota Jidosha Kogyo Kabushiki Kaisha

Kunio Endo

Susumu Harada

Norio Omori

Akio Kobayashi

Nobuyuki Kobayashi

Motoharu Sueishi

Haruo Watanabe

Mitsuo Kawai

Junji Kawarada

An apparatus for diagnosing a malfunction of an electronic control system including sensors for electrically sensing conditions of sensing points of a vehicle and an electronic calculation unit for determining an energizing condition of an actuator for controlling a vehicle operation in accordance with output signals from the sensors is disclosed. The malfunction diagnosing apparatus is inserted intermediate of wires which connect the sensors or the actuator and the electronic control system, and when a voltage or current level on any wire assumes a non-steady state, the malfunction diagnosing apparatus determines that a malfunction has occurred at a portion associated with that wire and memorizes and holds the occurrence of the malfunction.

Malfunction diagnosing apparatus for electronic control system for

An electronically-controlled fuel injection system for an internal combustion engine having odd numbers of cylinders, in which the quantity of fuel supplied to the engine cylinders is regulated by the duration of pulses of a fuel injection pulse signal applied to solenoid-operated fuel injection valves, and two fuel injection pulses are generated in each operating cycle of the engine in synchronism with the revolution of the engine. In the system, the frequency of an ignition signal generated by an ignition unit in the engine is doubled to provide an output pulse signal, and the frequency of sucn an output pulse signal is then divided by the number of engine cylinders so as to generate the fuel injection pulse signal in synchronism with this frequency-divided output pulse signal.

Electronically-controlled fuel injection system for internal combustion

An electronically-controlled fuel injection system for an internal combustion engine having odd numbers of cylinders, in which the quantity of fuel supplied to the engine cylinders is regulated by the duration of pulses of a fuel injection pulse signal applied to solenoid-operated fuel injection valves, and two fuel injection pulses are generated in each operating cycle of the engine in synchronism with the revolution of the engine. In the system, the frequency of an ignition signal generated by an ignition unit for the engine is divided by the number of cylinders of the engine to provide a first pulse signal and a second pulse signal. The phase of each pulse of the second pulse signal lags behind that of the first pulse signal by n ignition pulse intervals where n is a multiple number of the half of the number obtained by subtracting unity from the number of cylinders of the engine. A third pulse signal is further generated in which the fall time of each pulse is delayed by the half of one ignition pulse interval relative to the fall time of the corresponding pulse in the second pulse signal. The fuel injection pulse signal is generated in synchronism with the fall time of the pulses of the first and third pulse signals.

A rotational speed detecting apparatus for controlling the operation of an electronically controlled fuel injection system in accordance with the rotational speed of an engine. A reference pulse generator is connected to generate a reference pulse signal in synchronism with a pulse signal which is generated by the fuel injection system in substantial synchronism with the rotation of the engine. The reference pulse generator is further connected to change the time width of the reference pulse signal in response to the operation of a starter motor and a throttle valve so that it represents the predetermined rotational speeds of the engine. A comparison circuit is connected to compare the one cycle period of the pulse signal with the time width of the reference pulse signal. The output signal of the comparison circuit is applied to the fuel injection system so that it controls fuel enrichment and fuel cut-off operation of the fuel injection system.

Rotational speed detecting apparatus for electronically-controlled fuel

A fuel injection system in which the valve control pulses are generated on the basis of information regarding the engine rpm and the combustion air flow rate and in which the air flow rate is measured by a baffle plate and a position sensor. When the throttle is abruptly closed, the inertia of the air and of the baffle plate prevents a precise measurement and an overly lean fuel mixture may be admitted. Accordingly, the apparatus of the invention is sensitive to the rate of change of the signal from the baffle plate sensor and when that rate is too great, additional current is fed to a multiplying circuit, thereby extending the control pulse length and increasing the amount of fuel fed to the engine.

Fuel injection control system

An electronic fuel injection system generates primary fuel control pulses in synchronism with the crankshaft rotation. The width of these control pulses is adjusted according to the indications of various engine transducers and determines the amount of fuel to be injected. The system also includes an air flow rate transducer whose output signal is monitored by a comparator. When the air flow rate signal undergoes very rapid changes, the comparator triggers a secondary pulse generator which supplies additional fuel injection control pulses to admit more fuel. The occurrence of the secondary pulses is temporally independent of the primary pulses.

Electronic fuel injection system

An electronically-controlled fuel injection system for internal combustion engines is disclosed. Pulse width of a reference pulse generated in accordance with principal engine operating parameters is converted into a binary code and memorized. Oscillation signal having a frequency responsive to other engine operating parameters is counted starting in synchronism with the engine rotation until the count value thereof coincides with the memorized value. During the oscillation signal counting electromagnetically-operable injectors are opened sequentially in the engine suction stroke. The resultant fuel injection amount is dependent on the principal and other engine operating conditions.

Electronically-controlled fuel injection system

There is provided an air-fuel ratio control system for internal combustion engines wherein the direction of deviation of the actual air-fuel ratio from a preset air-fuel ratio is determined by an oxygen concentration detector for detecting the concentration of oxygen contained in the exhaust gases from an internal combustion engine and an air-fuel ratio discriminating circuit, whereby air is injected from an air injection valve when the air-fuel ratio is low i.e. the mixture is rich and fuel is injected from a fuel injection valve when the air-fuel ratio is high i.e. the mixture is lean, thereby controlling the air-fuel ratio to a predetermined value.

Growing community of inventors

Anjo, Japan

Kunio Endo