Abstract: A control system for an internal combustion engine has an air-fuel ratio sensor arranged in the exhaust system. An air-fuel ratio feedback control carried out based on an output from the air-fuel ratio sensor such that an air-fuel ratio of an air-fuel mixture supplied to the engine is converged to a desired air-fuel ratio is selected between a high-response feedback control using an adaptive controller of a recurrence formula type and a low-response feedback control with a lower response speed than a response speed of the high-response feedback control. Operating conditions of at least one of the engine and an automotive vehicle on which engine is installed are detected. It is determined whether or not the engine is in an unsteady operating condition in which combustion of the engine undergoes a variation, based on detected operating conditions of at least one of the engine and the vehicle.

Abstract: A feedback control system for maintaining the air/fuel ratio in a two-cycle internal combustion engine employing an oxygen sensor that senses the combustion products in a combustion chamber at the end of the combustion cycle. The feedback control system is discontinued when a misfire condition exists and the fuel amount supplied is decreased until the misfired condition subsides and then feedback control is returned.

Abstract: An aircraft piston engine control system according to the present invention has a fuel supply passage for supplying fuel to the engine. A fuel regulation device is arranged in the fuel supply passage, is linked to a throttle lever, and regulates an amount of fuel so as to realize a first air-fuel ratio which is more rich than the stoichiometric air-fuel ratio. A fuel decreasing passage is connected to the fuel supply passage between the fuel regulation device and the engine. A fuel decreasing device is arranged in the fuel decreasing passage, and decreases an amount of fuel regulated by the fuel regulation device so as to realize an optimum air-fuel ratio according to the current engine operating condition.

Abstract: An engine air/fuel control system and method is provided having feedback control responsive to an exhaust gas oxygen sensor. A fuel command responsive to the EGO sensor is modulated (312) and the modulation disabled in response to detection of an air/fuel transient period (502-510, 610). In addition, feedback control gain is increased (514, 614) and the modulation signal held at a value opposite the state of the EGO sensor occurring upon initiation of the air/fuel transient period (510, 610). An indication is provided that the air/fuel transient is terminated when the EGO sensor switching frequency resumes a normal condition (522-528, 622-628). Modulation is thereafter resumed and the feedback gain restored (532-538, 632-638).

Abstract: The invention relates to a method for optimizing exhaust quality of a combustion system, especially an internal combustion engine, wherein measured pollutant quantities in the exhaust are used to regulate the combustion system. According to the invention, the quantities of at least two pollutant components in the exhaust are measured using sensors, and a weighted composite signal is determined based on the measured quantities. This weighted composite signal is then set to a minimum by controlling an operating parameter that influences the exhaust composition. Such minimization can be performed continuously and sequentially as needed for a plurality of operating parameters that influence the exhaust composition.

Abstract: An Electronic Engine Controller (EEC) determines the actual dynamic response of an engine which uses a switching type Heated Exhaust Gas Oxygen Sensor (HEGO) by imposing a bias on the air/fuel (A/F) mixture when the engine is operating at steady state conditions and is combusting a stoichiometric A/F mixture. The A/F mixture is then abruptly altered and maintained for a predetermined period of time, and the time elapsed from the abrupt alteration to detection of the abrupt alteration by the HEGO sensor is measured and stored. Upon expiration of the predetermined period of time, the A/F mixture is abruptly altered to the biased A/F mixture and the time elapsed from the abrupt alteration to the biased value to the detection of the abrupt alteration is measured and stored. The bias value is then removed to return the A/F mixture to stoichiometry and the process is repeated for a plurality of bias values. The actual dynamic response of the engine is then determined as a function of the stored time durations.

Abstract: A system for detecting air-fuel ratio of an internal combustion engine by sampling outputs of an air-fuel ratio sensor installed at an exhaust system confluence point of said engine. A timing map is prepared to be retrieved by the engine speed and manifold absolute pressure to determine one among sampled data which are successively stored in buffers. It is selected such that as the engine speed decreases or the manifold absolute pressure increases, a datum sampled at earlier crank angular position is selected. At an engine equipped with a variable valve timing mechanism, a datum sampled at earlier crank angular position is selected in the valve timing is controlled for high engine speed provided that the engine speed and manifold absolute pressure is constant. The sampled data stored in the buffers may be transferred to another buffers at a predetermined crank angular position. The sampled data is corrected by an environmental conditions including atmospheric pressure, a mixture or sensor degradation.

Abstract: An air-fuel ratio control device for an internal combustion engine having an intake passage and an exhaust passage with a three way catalytic converter. The device comprises a fuel injector for injecting fuel and an air-fuel ratio detector for detecting an air-fuel ratio in the engine cylinder, which is arranged in the exhaust passage upstream of the three way catalytic converter. A first estimation device estimates an amount of intake air actually fed into the engine cylinder. A first decision device decides a target amount of fuel which must be fed into the engine cylinder to realize the stoichiometric air-fuel ratio, on the basis of the amount of intake air estimated by the first estimation device. A second estimation device estimates an amount of fuel actually fed into the engine cylinder, on the basis of the air-fuel ratio detected by the air-fuel ratio detector, and the amount of intake air estimated by the first estimation device.

Abstract: The invention relates to a system for controlling an internal combustion engine, in particular a self-igniting internal combustion engine. First means (200) specify a first signal (MLS, US) on the basis of at least one operating parameter (QK, N). Second means (235) specify a second signal (MLI) on the basis of at least the output signal from a lambda probe (125). A third means (220) calculates a third signal on the basis of the first signal and the second signal and applies it to a final controlling element (230). Furthermore, means (515, 520, 530, 610, 235) are provided for the temporal conditioning of the first and second signal.

Abstract: An air-fuel ratio control system for an internal combustion engine equipped with a three-way catalytic converter. The air-fuel ratio control system is basically arranged to feedback-control air-fuel ratio of air-fuel mixture to be supplied to the engine to fall in a stoichiometric range by regulating a basic fuel supply amount in accordance with an air-fuel ratio feedback correction coefficient. The air-fuel ratio feedback correction coefficient is corrected with an integrated amount which is set to be increased after the measured value of a lapsed engine revolution number exceeds a decision standard. The lapsed engine revolution number is stored in the memory, and the average value of the lapsed engine revolution number is renewed with this stored lapsed engine revolution number in the memory.

Abstract: A system for controlling the fuel delivery of an electronic injection system, whereby a processing unit determines the amount of fuel to be injected for achieving a substantially correct stoichiometric air/fuel ratio; which value is subsequently corrected by a coefficient calculated by integrating a signal comprising a signal supplied by a sensor located in the exhaust manifold of the engine and presenting a transfer function comprising a nonlinear characteristic and a delay seriously affecting system response. The system also comprises a processing unit for simulating the transfer function of the engine-sensor system and generating a signal simulating the signal actually produced by the sensor but minus the delay introduced by the sensor and the system; which signal is used for producing a correction signal which is added to the signal generated by the sensor for compensating the delay and so improving the dynamic response of the system as a whole.

Abstract: A closed loop control for an internal combustion engine with a positive crankcase ventilation is disclosed. According to this control system, the appearance of blowby gas is detected in response to variation in feedback correction coefficient (alpha), and a product of a transient blowby gas variable (BTBL) and a time dependent factor (B.sub.T) is calculated and a blowby gas recirculation coefficient (KBLRC) is modified by this product (BTBL.times.B.sub.T) to give a modified blowby gas recirculation coefficient (KBLRC2). This modified coefficient is used in calculating a fuel injection amount (Ti) during supply of substantial blowby gas to the combustion engine after start-up of the engine.

Abstract: An air-fuel ratio control system for an internal combustion engine controls the air-fuel ratio of a mixture supplied to the engine to a desired air-fuel ratio in response to an output from an exhaust gas ingredient concentration sensor. A first value of the desired air-fuel ratio is calculated based on the rotational speed of the engine and the load on the engine. A second value of the desired air-fuel ratio is calculated based results of determination on whether a vehicle on which the engine is installed has just started from a standing position thereof. A third value of the desired air-fuel ratio is calculated based on results of determination on whether the temperature of the engine is lower than a predetermined value. The largest value of at least the first to third values of the desired air-fuel ratio is set to a final value of the desired air-fuel ratio.

Abstract: In a burning condition detecting device in an internal combustion engine in which a high voltage is applied to a spark plug by way of a diode and a series gap of a distributor. A voltage charger circuit is provided to on-off actuates the primary coil to induce a charging voltage in the secondary circuit either during establishing the spark discharge or during a predetermined period of time immediately after an end of the spark discharge. The charging voltage is applied to the spark plug to electrically charge a stray capacity inherent in the spark plug so as to form a sparkplug voltage. A voltage divider circuit is provided to divide the sparkplug voltage in accordance with a high impedance element and a low impedance element. A voltage level detecting circuit is provided to detect a sparkplug voltage waveform divided by the voltage divider circuit.

Abstract: In a method for protecting a catalytic converter from overheating, a conventional misfire recognition method is used to determine whether misfires are occurring in a cylinder. If this is the case, an attempt is made to interrupt the fuel supply to the affected cylinder. If this succeeds, the remaining cylinders are supplied with a lean mixture. If it does not succeed, all the cylinders are operated with a rich mixture. The lean setting of the mixture in the case of interrupted fuel supply to the affected cylinder has the effect that after the combustions in the cylinders, no further fuel reaches the catalytic converter which could combust in the catalytic converter with the oxygen induced by the affected cylinder.

Abstract: According to an air-fuel ratio control method, an amount of fuel supplied to an internal combustion engine is calculated by the use of an air-fuel ratio correction coefficient set according to an output from an exhaust gas ingredient concentration sensor. An average value of the air-fuel ratio correction coefficient is calculated. When a difference between an actual value of opening of an exhaust gas recirculation control valve and a desired value of same set in response to operating conditions of the engine is larger than a predetermined value, the calculation of the average value of the air-fuel ratio correction coefficient is inhibited, or alternatively, an averaging rate in the calculation of the average value is decreased.

Abstract: In an internal combustion engine where in a predetermined driving state, the air-fuel ratio is feedback-controlled based on a detection signal of an air-fuel ratio sensor and in other driving state, the air-fuel ratio is feed-forward-controlled, the presence or absence of a misfire is judged from the detection signal of the air-fuel sensor at the time of the feed forward control, and when the presence of a misfire is judged, a warning is given.

Abstract: An air-fuel ratio control method for an internal combustion engine. An amount of fuel to be supplied to the engine is calculated in response to operating conditions of the engine and output from an exhaust gas ingredient concentration sensor, to thereby feedback-control the air-fuel ratio of a mixture supplied to the engine to a desired air-fuel ratio. The method comprises the steps of (1) calculating a fuel cooling correction value for compensating for a change in an actual air-fuel ratio caused by cooling effects of actually-injected fuel, according to at least one parameter which can determine the amount of fuel to be supplied to the engine, and (2) calculating the amount of fuel to be supplied to the engine by the use of the fuel cooling correction value.

Abstract: The present specification discloses a diagnosis system and an optimum control unit for an internal combustion engine. The basic concept of the present invention resides in that a random retrieved signal of which auto correlation function is an impulse shape is superposed on a signal of an internal combustion engine, said superposed signal is used to measure a change of an operation state of the internal combustion engine, and an optimum direction of a control value is detected by a correlation between said measured value and retrieved signal.