Honda Giken Kogyo Kabushiki Kaisha

Ngk Spark Plug Company, Limited

Honda Giken Kogyo K.k.

Tomohiko Kawanabe

Masahiko Asakura

Noritaka Kushida

Katsuhiko Kimura

Minoru Muroya

Takanori Shiina

Hiroshi Hasebe

Yasunari Seki

Yukihiro Matsumoto

Masahiro Ueda

Shinichi Kubota

Shin'ichi Kubota

Kouji Matsuura

Masahiko Yakuwa

Hisashi Igarashi

Kunio Noguchi

Hiroshi Ohno

Tessho Yamada

Yasuhisa Arai

Haruo Shimamura

Takefumi Hosaka

Katsuhisa Amano

Fumio Yatabe

A method of detecting failure of an exhaust gas component concentration sensor for detecting concentration of a component of exhaust gases from an internal combustion engine. The method comprises the steps of: (1) applying a predetermined voltage to the sensor, (2) determining whether or not a change in an output voltage from the sensor caused by the application of the predetermined voltage to the sensor is smaller than a predetermined value, and (3) deciding that the sensor is faulty when the change in the output voltage is smaller than the predetermined value. A device for sensing concentration of a component of exhaust gases from an internal combustion engine comprising an electric resistance member connected in series between an electric current supply source and one of a pair of electrodes provided on a solid electrolytic element. A device for detecting failure of an exhaust gas component concentration sensing device comprising a constant voltage supply source for applying a predetermined voltage to the sensing device, and a switch connected between the constant voltage supply source and one of a pair of electrodes provided on an electrolytic element of the sensing device, for applying the predetermined voltage to the one of the electrodes when the switch is closed.

Exhaust gas component concentration sensing device and method of

An air-fuel ratio control system for an internal combustion engine mounted on a vehicle with a transmission, including an oxygen concentration sensor producing an output signal whose level is substantially proportional to an oxygen concentration of the exhaust gas, effects a feedback control of the air-fuel ratio of mixture to be supplied to the engine toward a target value determined on the basis of various parameters of the engine operation and corrected in response to a magnitude of atmospheric pressure, so that the higher a shift position of the transmission gear is, the leaner the target air-fuel ratio becomes. Thus, the fuel consumption in a light load operating condition of the engine is decreased and the driveability of the vehicle is improved.

Air-fuel ratio control system for an internal combustion engine with an

A method for indicating a shift operation for a manual transmission gear includes a step for comparing a detected vehicle speed with a reference speed which is determined and changed on the basis of a detected engine temperature and a step for indicating the shift operation on this basis of a result of the comparison. When a temperature parameter relating to the engine operation is lower than a predetermined reference temperature value, the reference vehicle speed is raised so that the indication of the shift operation will not be generated.

Method of indicating a shift operation of a manual transmission gear of

A device for detecting the air-fuel ratio of an engine by measuring an oxygen concentration of the exhaust gas by means of an oxygen sensor including an oxygen pump and a cell element for measuring the oxygen concentration ratio, comprising an air-fuel ratio detecting circuit which reads the output signal of the oxygen sensor and effects the detection of the air-fuel ratio when TDC signal has been produced, depending upon the operation of the engine, and a time previously set by a timer has passed.

Device for detecting air-fuel ratio of engine

A method of indicating when a shift operation of a manual gearbox is to be preformed includes a step for comparing a detected vehicle speed with a reference vehicle speed which is determined and changed on the basis of a detected engine operational parameter and a step for indicating that the shift operation should be performed on the basis of a result of the comparison. The reference vehicle speed is corrected to a lower speed in response to an increase of a total running time of the vehicle, thereby to maintain the driveability of the vehicle when the running time of the vehicle is short.

Method of indicating a shift operation of a manual gearbox of a vehicle

An apparatus for sensing the concentration of oxygen in a gas such as engine exhaust gas includes an oxygen concentration sensor formed of an oxygen pump element and a sensor cell element, each based on a solid electrolytic member formed of a material such as ZrO.sub.2, and is provided with a limiter circuit which functions to reduce the level of current supplied to the oxygen pump element when a voltage produced by the sensor cell element indicates that this current level is such as to produce a 'blackening' phenomenon whereby deterioration of the oxygen pump element will occur and oxygen concentration sensing reliability will be lowered. The apparatus also includes a delay circuit which functions such that a reduction of the oxygen pump element current level is delayed by a predetermined time interval, after an increase of the sensor cell element voltage to the 'blanking' region is detected, thereby preventing fluctuations in the oxygen pump element current level due to transient increases in sensor cell element voltage and increasing the sensing reliability.

Oxygen concentration sensing apparatus

A method of controlling an oxygen concentration sensor of the type having oxygen pump and sensor cell elements spaced from each other to form a gap or a restricted region both of which are to be placed in some gases containing an oxygen component, and a heater element for heating said oxygen pump and sensor cell elements under energization of a heater current supplied thereto. A pump current is supplied to the oxygen pump element as long as the heater current is supplied to the heater element. However, the initiation of the supply of the pump current is somewhat delayed at the initial stage of the supply of the heater current in order to avoid incorrect operation due to the unstable cool state of the sensor, and to present possible flow of excessive pump current through the pump element which would cause deterioration of the oxygen pump element.

Method for controlling an oxygen concentration sensing device

A device for detecting the air-fuel ratio of an engine by measuring the oxygen concentration of the exhaust gas by means of an oxygen sensor including an oxygen pump and a cell element for measuring the oxygen concentration ratio, comprising a filter circuit for smoothing the output signal of the oxygen sensor, said filter circuit having a time constant which is variably set so that it is in proportional relation to the number of revolutions per units of time of the engine.

An air intake side secondary air supply system for an internal combustion engine having an air intake side secondary air supply system includes an oxygen concentration sensor, and controls a duty ratio of opening and closing of an open/close valve disposed in the air intake side secondary air supply passage by determining a valve open period within each duty cycle of control operation in accordance with a result of comparison between the level of the output signal of the oxygen concentration sensor and a level corresponding to a target air-fuel ratio. The duty ratio of opening and closing of the open/close valve is maintained within a predetermined duty ratio range so as to improve effectiveness of the control of the secondary air supply as well as to avoid the generation of over lean or over rich mixture.

Air intake side secondary air supply system for an internal combustion

The valve opening of an exhaust gas recirculating valve is controlled in response to operating conditions of the engine so as to regulate the amount of exhaust gas recirculation to values appropriate to the operating conditions of the engine. The valve opening of the exhaust gas recirculating valve is varied by a predetermined value when the engine is determined to be in a predetermined accelerating condition or a predetermined decelerating condition. Further, the predetermined value is corrected in accordance with the detected shift lever position. Preferably, the valve opening of the exhaust gas recirculating valve is increased or decreased by a predetermined incremental value or a predetermined decremental value when the engine is in the predetermined accelerating condition or the predetermined decelerating condition, and the predetermined incremental value or the predetermined decremental value is corrected in accordance with the detected position of the shift lever.

Exhaust gas recirculation method for internal combustion engines

A method for directing an up shift operation for a vehicle having an engine and a manual transmission generates a direction of an up-shift operation when the vehicle speed exceeds a reference speed determined for each gear position. The reference speed of a medium speed gear is varied according to the degree of acceleration at the time of the previous up-shift operation. If the up-shift operation from a low speed gear to the medium speed gear is effected while the vehicle is not accelerating rapidly, the reference speed for an up shift operation from the medium speed gear is lowered. Further, if a cruising state of the vehicle with the medium speed gear after the acceleration is continued for more than a predetermined time period, the reference speed for an up-shift operation from the medium speed gear is also lowered.

Method for directing an up-shift operation for a vehicle having a manual

An air/fuel ratio control system for an internal combustion engine having an air supply system for controlling the air/fuel ratio of mixture to be supplied to the engine, and an oxygen concentration sensing device for sensing the oxygen concentration in the exhaust gas of the internal combustion engine. The oxygen concentration sensing device includes a pair of solid electrolyte members operating as an oxygen pump element to which a pump current is supplied, and a sensor cell element. An open/close valve is provided in the air supply system and controlled by a duty ratio control circuit which causes the open/close valve to be opened for a calculated valve open time period in each of successive predetermined cycles in response to a result of detection of air/fuel ratio. When the calculated valve open time period exceeds a predetermined upper limit, the supply of the pump current is stopped so that the blackening phenomenon of the solid electrolyte members is avoided.

Air/fuel ratio control system for an internal combustion engine with a

Method for controlling an oxygen concentration sensor for sensing an oxygen concentration in an exhaust gas of an internal combustion engine, which sensor includes an oxygen pump element and a heater element, comprises steps for controlling a pump current and a heat current control in response to a result of a detection of engine load. When the engine is operating in a predetermined high load range, the supply of the pump current to the oxygen pump element is stopped, and the heat current to the heater element is reduced when the engine operation in the high load range has continued for more than a predetermined time period. The heater current to the heater element is stopped when the engine load is in a first predetermined load range, and when the engine operation in a second load range which is lighter than the first load range has continued for a predetermined time period.

Method for controlling an oxygen concentration sensor for sensing an

An air intake side secondary air supply system for an internal combustion engine having an air intake system using a carburetor and an air intake side secondary air supply passage leading to the downstream of the carburetor, includes an oxygen concentration sensor producing an output signal whose level is substantially proportional to an oxygen concentration of the exhaust gas. A control means for controlling a duty ratio of opening and closing of an open/close valve disposed in the air intake side secondary air supply passage in accordance with a result of comparison between the level of the output signal of the oxygen concentration sensor and a level corresponding to a target air-fuel ratio. The target air-fuel ratio is up-dated in response to at least two parameters indicative of the engine operation.

An air intake side secondary air supply system for an internal combustion engine including an open/close valve disposed in an air intake side secondary air supply passage and an oxygen concentration sensor producing an output signal whose level is substantially proportional to an oxygen concentration of the exhaust gas, executes a duty ratio control of the open/close valve for a feedback control of the air fuel ratio of mixture to be supplied to the engine. When the air/fuel ratio has changed from rich to lean with respect to a target air/fuel ratio, a correction value for reducing the valve open period during the air/fuel ratio is detected to be lean, is increased. On the other hand, when the air/fuel ratio has changed from lean to rich with respect to the target air/fuel ratio, a correction value for increasing the valve open period during the air/fuel ratio is detected to be rich, is increased.

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Wako, Japan

Tomohiko Kawanabe