Nippondenso Co., Ltd.

Toyota Jidosha Kogyo Kabushiki Kaisha

Nippondenxo Co., Ltd.

Akio Kobayashi

Toshio Kondo

Shigenori Isomura

Susumu Harada

Masakazu Honda

Takashi Harada

Masahiko Tajima

Tomomi Eino

Takehiro Kikuchi

Yasuo Sagisaka

Akira Masuda

Katsuhiko Kodama

Norio Omori

Hideaki Norimatsu

Toshihiko Muramatsu

Kunio Endo

Katsushi Kato

Shuji Sakakibara

Sigenori Kitajima

Takeshi Matsui

Masatoshi Suzuki

Masahiko Miyaki

Yukihide Niimi

Masaya Fujimoto

Yasumasa Kaji

Ryosuke Tachi

Naofumi Fukue

Shunichiro Hiromasa

Ichiro Kowada

Sachio Nishii

Takehiro Kikuti

In a computer-controlled fuel supply system of an internal combustion engine, two basic pieces of information, i.e. airflow data Q and engine speed data N, are processed by an analog operating circuit to produce a basic injection pulse signal, whose pulse width equals Q/N. The data Q/N is used by a microcomputer, when the microcomputer is in normal state, to produce a corrected injection pulse signal by using various engine parameters in the same manner as in conventional arrangements, and fuel flow is determined by the width of the corrected injection pulse signal. When malfunctioning of the microcomputer is detected, the basic injection pulse signal from the analog operating circuit is used in place of the corrected injection pulse signal from the microcomputer to determine the fuel flow. The width of the basic injection pulse signal may be lengthened when the microcomputer is in abnormal state so that air/fuel ratio is almost accurately controlled without the microcomputer.

Air/fuel ratio control for an internal combustion engine with improved

An electronic control apparatus for use in vehicles comprised of two, one-chip microcomputers. The microcomputers each have a ROM and a RAM and are used to control different systems provided in the vehicle. The ROM of the second microcomputer stores an operational program which can be used to calculate control values for controlling various types of devices. It also stores operational map data which can be used to calculate control values for controlling various types of devices. Various signals output by the sensors provided in the vehicle are supplied to both microcomputers. At the start of the power supply to the apparatus, the operational map data stored in the ROM of the first microcomputer, which is to be used by the second microcomputer, is transferred to the RAM of the second microcomputer. The second microcomputer calculates a control value from the transferred operational map data, the signals output by the sensors and other data, thereby controlling the system assigned to it.

Electronic control apparatus including microcomputers for controlling

In a fuel control system for an internal combustion engine, high and low voltages are applied in succession to an oxygen sensor, the difference between currents generated successively by the sensor in response to the application of the voltages being detected and compared with a predetermined value. The ratio of air-fuel mixture is controlled as a function of the current generated by the sensor in response to the application of one of the high and low voltages when the difference is smaller than the predetermined value and controlled in an open loop mode when the difference is larger than the predetermined value.

Fuel control system having sensor verification dual modes

An apparatus for measuring a flow of intake air to an engine includes a bridge circuit including a heat resistor placed in an intake air path of the engine, a resistor for sensing the temperature of the intake air, and a plurality of balance resistors. A heating current is supplied to this bridge circuit through a transistor controlled by a periodical current-passage control signal generated by a microcomputer. A signal Vh, representing a temperature change of the heat resistor heated by the heating current, is detected by the microcomputer. A first correction value is computed by using a difference between the detected value from the microcomputer and a signal Vho, representing temperature of the heat resistor when the bridge circuit is balanced at normal temperature. A time width correction value .DELTA.Do1 is computed from a table on the basis of the first correction value. The correction signal .DELTA.Do1 is used for correcting the current passage time. The current passage time width as corrected is used for computing a flow of the intake air.

Apparatus for measuring a flow rate of intake air for an engine

In an electronic fuel injection control system for an internal combustion engine, a first integration circuit is responsive to an angular signal with a time period in inverse proportion to the rotational speed of the engine for integrating the first half of the time period of the angular signal and for producing a first integration signal indicative of a resultant value of the integration, a hold circuit is arranged to hold the value of the first integration signal upon lapse of the first half of the time period and to produce a hold signal of the held value and maintain it for the second half of the time period and the first half of the time period of the following angular signal, a second integration circuit is responsive to the angular signal for integrating the value of an air quantity signal indicative of the quantity of air drawn into the engine at each start of the first and second halves of the time period and for producing a second integration signal indicative of a resultant value of the integration of the value of the air quantity signal, and a signal generator is arranged to determine a fuel injection time based on the time required for arrival of the valve of the second integration signal to the level of the hold signal after each start of the first and second halves of the time period.

Electronic fuel injection control system for internal combustion engine

A mixture control system comprises an oxygen sensor for generating a sensor signal varying linearly as a function of the oxygen concentration of exhaust emissions from an internal combustion engine when the air-fuel ratio of mixture supplied thereto is leaner than stoichiometric value. Optimum values of the sensor signal are stored in storage locations of a memory addressable as a function of detected engine operating parameters. A data processor determines the quantity of fuel to be supplied to the engine in accordance with the detected engine operating parameters, addresses the memory as a function of the detected engine operating parameters, detects a difference between the sensor signal and a signal addressed in the memory, integrates the difference and corrects the fuel quantity with the integrated value.

Lean mixture control system using a biased oxygen concentration sensor

An oxygen concentration detector under a temperature control for an internal combustion engine. An oxygen sensor of a critical current type is held between a gas under test and a reference gas, in the vicinity of which a heater is located for heating up the oxygen sensor in a sensor activating temperature range. A first voltage is applied for a positive bias control to the oxygen sensor during a first period, and a second voltage is applied for a negative bias control thereto during a second period. Electric current flowing through the oxygen sensor is detected during the first period in order to detect the oxygen concentration in the gas under test. The current value is also detected during the second period in order to detect and maintain constant the internal electric resistance of the oxygen sensor by controlling the heater heating output.

Oxygen concentration detector under temperature control

A control device for vehicles includes a microcomputer having an output port which outputs a signal in a normal operating state of the microcomputer, and two electronic circuits associated with the microcomputer. The two electronic circuits operate to change a control mode for the vehicle to a fallback mode upon occurrence of a malfunction or misoperation in the microcomputer thereby to prevent the vehicle from operating in a dangerous running condition caused by erroneous control due to the misoperation by the microcomputer.

Control device for a vehicle

A fuel injection control for an internal combustion engine having electromagnetic fuel injectors determines a basic fuel injection time width of a fuel injection pulse signal applied to the electromagnetic fuel injectors in accordance with detected conditions of engine operation parameters, stores maximum fuel injection time width values predetermined in correspondence to values of a predetermined one of the engine operation parameters, reads one of the predetermined maximum fuel injection time width values corresponding to the values of the predetermined engine operation parameter and corrects the same in accordance with the values of the other engine operation parameters, and corrects the basic fuel injection time width in accordance with the corrected predetermined maximum fuel injection time width value, thereby controlling the air-fuel ratio at a desired air-fuel ratio under every operating condition of the engine, while simultaneously preventing a misoperation of continuous fuel supply from occuring in the electromagnetic fuel injectors as before.

Fuel injection control

An electronic control type fuel injection system in which, at the time of engine deceleration the fuel injection is stopped, and when resuming to a normal fuel injection from the fuel injection stopped condition, if the reducing rate of the engine speed is smaller than a preset value, a smaller amount of fuel than the amount of fuel injection during normal operation as if fuel injection had not been stopped is first injected and subsequently the amount of fuel to be injected is gradually increased, while when the reducing rate of the engine speed is larger than the preset value, a larger amount of fuel than the fuel injection amount during normal operation is injected.

Electronic control type fuel injection system

In an air-fuel ratio control system for an internal combustion engine, the basic fuel injection amount computed from engine parameters such as engine speed and intake air flow is corrected by using map having air-fuel ratio compensation data stored battery back-up in accordance with the engine parameters. The compensation data is read out of the map in accordance with the parameters at the time of detection of the stable combustion state of the engine. When an output of an oxygen sensor is on lean side, a predetermined amount is added to the data thus read, while when the output of the oxygen sensor is on rich side, a predetermined amount is subtracted from the data thus read, thereby renewing the stored value.

Air-fuel ratio control for internal combustion engine

In a closed loop control system for air/fuel ratio control of an internal combustion engine, an integration correction factor is derived from the output signal of a gas sensor indicative of the concentration of an exhaust gas component, and an engine condition correction factor is selected from a memory in which a plurality of engine condition correction factors are prestored in the form of a table. The engine condition correction factor is renewed in accordance with the variation in the value of the integration correction factor so as to perform learning control. In order to prevent each of the engine condition correction factors from assuming an undesirable value which are far deviated from its standard, a constant or variable limit value is set. The limit value may be set by calculating some typical engine condition correction factors. The correction factors will be used to modify a basic quantity of fuel to be injected into each cylinder of the engine for feedback controlling the air/fuel ratio of the air/fuel mixture.

Closed loop air/fuel ratio control using learning data each arranged not

An electronic control system for fuel injection into an engine controls an air-fuel ratio at a desired air-fuel ratio during a high load operation of the engine. The electronic control system performs the operations of detecting operating parameters of the engine, computing by a computing unit a time width in accordance with the detected operating parameters, selecting a maximum time width value of the injection pulse from a preliminarily stored table of maximum time width values thereof in accordance with the value of at least one of the detected operating parameters, comparing the computed time width value with the selected maximum time width value, limiting the computed time width value in accordance with the selected maximum time width value, and applying the injection pulse to the fuel injectors, thereby controlling the air-fuel ratio under the high load conditions at a desired air-fuel ratio and also preventing the malfunction of continuous fuel supply from occurring in the fuel injectors.

Electronic control for fuel injection

A method and an apparatus for controlling the air-fuel ratio in an internal combustion engine in which the calculation of the presumed amount of fuel attached to the wall of the intake port of the engine is effected for correcting the amount of the fuel supplied to the engine in order to compensate for the variation of the air-fuel ratio of the air-fuel mixture used in the combustion of the engine.

Method for controlling the air-fuel ratio in an internal combustion

A closed loop mixture control system for internal combustion engines is responsive to a signal derived from an exhaust gas sensor. The sensor signal is time-integrated in a direction depending on the level of the gas sensor output to derive a first mixture corrective setting of the control system. Second corrective settings or learning data are established for the control system in correspondence with the amount of air supplied to the engine. Each of the latter settings is varied as a function of time in a direction depending on the value of the time-varying first corrective setting relative to a reference so that the second settings are automatically updated to meet varying engine performance such as aging. One of the second corrective settings is selected in response to the detected quantity of the supplied air and multiplied by the first corrective setting to correct the basic mixture control setting of the system toward an optimum value. All of the second corrective settings are reset to appropriate values, for example, '1' at the instant the engine is started if an average value of the second settings is greater than a predetermined value to compensate for different fuel vaporizations.

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Kariya, Japan

Akio Kobayashi