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: Disclosed is a valve stopping device for an internal combustion engine that does not allow valves for all cylinders to stop in the closed state even in the event of a failure. The valve stopping device includes a control device 2 and a plurality of actuators 4A, 4B, 4C, 4D, which stop either an intake valve or an exhaust valve. The actuators 4A, 4D for some of a plurality of cylinders included in the internal combustion engine stop a valve in the closed state when energized. The actuators 4B, 4C for the remaining cylinders stop a valve in the closed state when energized. The control device 2 provides control on an individual actuator basis to determine whether or not to energize the actuators 4A, 4B, 4C, 4D.

Abstract: A control device for an internal combustion engine. An object of the present invention is to provide a control device for an international combustion engine for highly accurate absolute pressure correction irrespective of the length of an adiabatic compression stroke period. When the number of cylinders in an engine is n (n is an integer of 2 or more), an adiabatic compression stroke period of one cylinder preceding another cylinder to be corrected into its absolute pressure by a 1/n cycle (ignition timing—IVC) is compared with a threshold CATH (step 100). In the step 100, the absolute pressure correction is carried out based on PV?=constant when the adiabatic compression stroke period is longer than the threshold CATH (step 110). On the other hand, the absolute pressure correction is carried out based on a value PIP detected by an intake pipe pressure sensor when the adiabatic compression stroke period is shorter than the threshold CATH.

Abstract: An internal combustion engine which is provided with a variable compression ratio mechanism which can change a mechanical compression ratio and a variable valve timing mechanism which can control a closing timing of an intake valve. No-entry regions (X1, X2) are set for a combination of the mechanical compression ratio, the closing timing of the intake valve, and the intake air amount. Furthermore, a no-entry layer is set so as to surround the no-entry region (X2). When the demanded intake air amount is made to decrease and the operating point moves toward the no-entry region (X2), the operating point is prohibited from entering the no-entry layer whereby the operating point is blocked from entering the no-entry region (X2).

Abstract: An internal combustion engine which is provided with a variable compression ratio mechanism which can change a mechanical compression ratio and a variable valve timing mechanism which can control a closing timing of an intake valve. A target operating point which can be reached after a fixed time without entering no-entry regions from the current operating point toward an operating point which satisfies the demanded intake air amount is calculated for an operating point which shows a combination of the mechanical compression ratio and the closing timing of the intake valve when the demanded intake air amount changes, and the mechanical compression ratio and the closing timing of the intake valve are made to change toward this target operating point.

Abstract: A control device for a multi-cylinder internal combustion engine that is equipped with a variable compression ratio mechanism includes an air-fuel ratio sensor, and a controller that determines whether or not actual mechanical compression ratios in cylinders of the internal combustion engine are uniform. The controller controls the variable compression ratio mechanism by decreasing a target mechanical compression ratio from a current first target mechanical compression ratio to a second target mechanical compression ratio without changing the amount of intake air and a fuel injection amount, and determines that the actual mechanical compression ratios in the cylinders are not uniform when the target mechanical compression ratio is set at the first target mechanical compression ratio if the differences in the output air-fuel ratios from the air-fuel ratio sensor for exhaust gases from the cylinders before and after the control of the variable compression ratio mechanism are not uniform.

Abstract: Disclosed is a valve stopping device for an internal combustion engine that does not allow valves for all cylinders to stop in the closed state even in the event of a failure. The valve stopping device includes a control device 2 and a plurality of actuators 4A, 4B, 4C, 4D, which stop either an intake valve or an exhaust valve. The actuators 4A, 4D for some of a plurality of cylinders included in the internal combustion engine stop a valve in the closed state when energized. The actuators 4B, 4C for the remaining cylinders stop a valve in the closed state when energized. The control device 2 provides control on an individual actuator basis to determine whether or not to energize the actuators 4A, 4B, 4C, 4D.

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: 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.