Abstract: With the use of a model expression (FIG. 9C), of which inputs include a desired value of an in-cylinder air amount that is a controlled object of a system and predetermined parameters, such as engine speed (ne), a desired throttle opening degree (?ref) required to control the in-cylinder air amount to the desired value is calculated. In this model expression, parameters, such as the engine speed (ne), that oscillate at a relatively high frequency are excluded from subjects of differentiation, and the desired in-cylinder air amount value only is included in the subjects of differentiation.

Abstract: A change in a torque request for an internal combustion engine during a prediction period is predicted as a change in a target torque. Further, a change in an outputtable upper-limit torque during the prediction period is calculated as an upper-limit torque change. When the target torque is greater than the upper-limit torque by more than a judgment value during the prediction period, control is exercised to increase an intake air amount. Moreover, the torque difference between the target torque and upper-limit torque at a second time, which is later than a first time, is calculated to correct the torque difference with higher responsiveness than exhibited for intake air amount control.

Abstract: An internal combustion engine torque estimation device that accurately estimates the torque of an internal combustion engine without being affected by engine speed changes. A reference signal, which is output at predetermined rotation angle intervals of a crankshaft for the engine, is acquired. In accordance with the reference signal, the amount of change in the rotation speed of the crankshaft is acquired as a rotational fluctuation. A filtering process is performed on the rotational fluctuation in synchronism with reference signal output timing to extract a frequency component synchronized with a combustion cycle of the engine. The torque of the engine is estimated in accordance with the extracted frequency component.

Abstract: A concentration detector comprises oxygen-forming means for forming oxygen by decomposing the particular component in the gas, first output means for producing an output value proportional to the oxygen concentration in the gas of before oxygen is formed by the oxygen-forming means, second output means for producing an output value proportional to the oxygen concentration in the gas after oxygen is formed by the oxygen-forming means, concentration calculation means for calculating the concentration of the particular component in the gas based upon the output value from the first output means and upon the output value from the second output means by using a coefficient for bringing the output characteristics of the first output means into agreement with the output characteristics of the second output means, and means which feeds at least two kinds of gases containing the particular component at a constant concentration and containing oxygen at different concentrations to said first output means and calculates

Abstract: A concentration detector for detecting the concentration of a particular component in a gas based upon the amount of oxygen formed by the decomposition of the particular component, comprising oxygen-forming means for forming oxygen by decomposing the above particular component, oxygen-discharging means for discharging oxygen from the gas before oxygen is formed by the oxygen-forming means, and oxygen-discharging capability-increasing means for increasing the oxygen-discharging capability of the oxygen-discharging means when the rate of increase of the oxygen concentration in the gas is greater than a predetermined rate before oxygen is formed by the oxygen-forming means.

Abstract: A concentration detector comprises oxygen-forming means for forming oxygen by decomposing the particular component in the gas, first output means for producing an output value proportional to the oxygen concentration in the gas of before oxygen is formed by the oxygen-forming means, second output means for producing an output value proportional to the oxygen concentration in the gas after oxygen is formed by the oxygen-forming means, concentration calculation means for calculating the concentration of the particular component in the gas based upon the output value from the first output means and upon the output value from the second output means by using a coefficient for bringing the output characteristics of the first output means into agreement with the output characteristics of the second output means, and means which feeds at least two kinds of gases containing the particular component at a constant concentration and containing oxygen at different concentrations to said first output means and calculates

Abstract: A concentration detector for detecting the concentration of a particular component in a gas based upon the amount of oxygen formed by the decomposition of the particular component, comprising oxygen-forming means for forming oxygen by decomposing the above particular component, oxygen-discharging means for discharging oxygen from the gas before oxygen is formed by the oxygen-forming means, and oxygen-discharging capability-increasing means for increasing the oxygen-discharging capability of the oxygen-discharging means when the rate of increase of the oxygen concentration in the gas is greater than a predetermined rate before oxygen is formed by the oxygen-forming means.

Abstract: Disclosed is a control device, which controls an air-fuel ratio sensor that is mounted in an exhaust path of an internal-combustion engine. The air-fuel ratio sensor is capable of pumping oxygen in a gas. Normally (time t0-t1, time t3 or later), a positive voltage Vp1 is applied to a sensor element (FIG. 7A), and the air-fuel ratio is calculated (FIG. 7C) in accordance with a sensor current (FIG. 7B). A heater is driven after internal-combustion engine startup to heat the sensor element. In a process in which the sensor element temperature rises, a negative voltage Vm, which is oriented in a direction different from that of the positive voltage Vp1, is applied to the sensor element.