Abstract: An output signal of a knock sensor is converted by an A/D conversion part in a specified knock determination range. In a time-frequency analysis part, data of frequency, time, and vibration intensity are extracted at the same time from an output signal of the knock sensor, and the time-varying patterns of vibration intensities in multiple frequency ranges are extracted. A knock determination part computes the number of time-varying patterns of vibration intensity which rise at same time. The knock determination part executes a knock determination based on whether the number of the time-varying patterns of vibration intensity is greater than a knock determination threshold.

Abstract: An output signal of a knock sensor is converted by an A/D conversion part in a specified knock determination range. In a time-frequency analysis part, data of frequency, time, and vibration intensity are extracted at the same time from an output signal of the knock sensor and the time-varying patterns of vibration intensities in multiple frequency ranges are extracted. A knock determination part computes lengths (crank angle, or time period) from a starting point to a latest terminating point of the time-varying patterns of vibration intensity in at least two frequency ranges, which rise at a same time. The knock determination part executes a knock determination based on whether the lengths are greater than a knock determination threshold.

Abstract: An output of a knock sensor is A/D converted in a specified knock determination range. In a time-frequency analysis part, data of frequency, time, and vibration intensity are extracted at the same time from the knock sensor output signal and the time-varying patterns of vibration intensities in multiple frequency ranges are extracted. An edge direction and an edge intensity are computed by an edge extraction processing. A correlation value expressing a correlation between time-varying patterns of vibration intensities in multiple frequency ranges and a reference model expressing the feature of knock is computed in a mutual correlation/knock determination part. The correlation value is compared with a determination threshold. When the correlation value is larger than the determination threshold, it is determined that knock is caused. When the correlation value is not larger than the determination threshold, it is determined that knock is not caused.

Abstract: A fuel injection controller for an internal combustion engine. The engine includes a fuel vapor treatment device having a collector for collecting fuel vapor generating in a fuel tank; a purge line that introduces purge gas into an intake passage of the engine, the purge gas being a mixture of fuel vapor released from the collector and air; and a purge valve provided in the purge line to adjust flow rate of the purge gas. The fuel injection controller corrects an amount of fuel injected from an fuel injection valve based on an amount of fuel vapor contained in the purge gas flowing into a combustion chamber of the engine. The fuel injection controller comprises an estimation section for estimating the inflow amount of the purge gas flowing into the combustion chamber based on a passed amount of purge gas that has passed through the purge valve and a compensation value for compensating transportation delay.

Abstract: An engine has a variable valve actuation mechanism that varies lift characteristics of an intake valve. An idle speed control apparatus has a control section for controlling an intake air amount of the engine in an idle state for adjusting an actual engine speed to a target engine speed. The control section sets a control amount related to control of the intake air amount in correspondence with the lift characteristics, which are varied by the variable valve actuation mechanism. Accordingly, the engine speed in the idle state is effectively controlled in correspondence with changes of the lift characteristics.

Abstract: An output signal of a knock sensor is converted by an A/D conversion part in a specified knock determination range. In a time-frequency analysis part, data of frequency, time, and vibration intensity are extracted at the same time from an output signal of the knock sensor, and the time-varying patterns of vibration intensities in multiple frequency ranges are extracted. A knock determination part computes the number of time-varying patterns of vibration intensity which rise at same time. The knock determination part executes a knock determination based on whether the number of the time-varying patterns of vibration intensity is greater than a knock determination threshold.

Abstract: An output signal of a knock sensor is converted by an A/D conversion part in a specified knock determination range. In a time-frequency analysis part, data of frequency, time, and vibration intensity are extracted at the same time from an output signal of the knock sensor and the time-varying patterns of vibration intensities in multiple frequency ranges are extracted. A knock determination part computes lengths (crank angle, or time period) from a starting point to a latest terminating point of the time-varying patters of vibration intensity in at least two frequency ranges, which rise at a same time. The knock determination part executes a knock determination based on whether the lengths are greater than a knock determination threshold.

Abstract: A knock sensor signal is converted by an A/D conversion part in a specified knock determination range. In a time-frequency analysis part, data of frequency, time, and vibration intensity are extracted at the same time from an output signal of the knock sensor and the time-varying patterns of vibration intensity of multiple frequency ranges are extracted. Contours of the time-varying patterns of vibration intensity in multiple frequency ranges are extracted. Vectors indicating directions along which the vibration intensities vary are approximated by the contour of the time-varying pattern of vibration intensity in each frequency range according to the least-squares method. A knock determination is executed based on whether directions of any two or more of multiple vectors are within a predetermined range. Alternatively, a knock determination is executed based on whether a ratio of length of any two or more of the vectors is within a predetermined range.

Abstract: An output of a knock sensor is A/D converted in a specified knock determination range. In a time-frequency analysis part, data of frequency, time, and vibration intensity are extracted at the same time from the knock sensor output signal and the time-varying patterns of vibration intensities in multiple frequency ranges are extracted. An edge direction and an edge intensity are computed by an edge extraction processing. A correlation value expressing a correlation between time-varying patterns of vibration intensities in multiple frequency ranges and a reference model expressing the feature of knock is computed in a mutual correlation/knock determination part. The correlation value is compared with a determination threshold. When the correlation value is larger than the determination threshold, it is determined that knock is caused. When the correlation value is not larger than the determination threshold, it is determined that knock is not caused.

Abstract: A fuel injection controller for an internal combustion engine. The engine includes a fuel vapor treatment device having a collector for collecting fuel vapor generating in a fuel tank; a purge line that introduces purge gas into an intake passage of the engine, the purge gas being a mixture of fuel vapor released from the collector and air; and a purge valve provided in the purge line to adjust flow rate of the purge gas. The fuel injection controller corrects an amount of fuel injected from an fuel injection valve based on an amount of fuel vapor contained in the purge gas flowing into a combustion chamber of the engine. The fuel injection controller comprises an estimation section for estimating the inflow amount of the purge gas flowing into the combustion chamber based on a passed amount of purge gas that has passed through the purge valve and a compensation value for compensating transportation delay.

Abstract: A combustion condition for each of plural cylinders included in an internal combustion engine is set by the following control that is performed according to an intake air amount in each of the plural cylinders. A reference cylinder is set to a cylinder in which the intake air amount is smallest, and a fuel injection amount for the reference cylinder is set to a fuel injection amount for realizing a stoichiometric air-fuel ratio. The air-fuel ratio in each of the cylinders other than the reference cylinder is set according to the intake air amount in each of the cylinders such that the torque equal to reference torque generated in the reference cylinder is generated. When this setting is performed, air-fuel ratios that are out of a predetermined region in the vicinity of the stoichiometric air-fuel ratio (i.e., air-fuel ratios that are in an avoidance region) are excluded.

Abstract: An engine has a variable valve actuation mechanism that varies lift characteristics of an intake valve. An idle speed control apparatus has a control section for controlling an intake air amount of the engine in an idle state for adjusting an actual engine speed to a target engine speed. The control section sets a control amount related to control of the intake air amount in correspondence with the lift characteristics, which are varied by the variable valve actuation mechanism. Accordingly, the engine speed in the idle state is effectively controlled in correspondence with changes of the lift characteristics.

Abstract: An engine adjusts the amount of intake air by cooperative control for the valve duration of the intake valve and the opening degree of the throttle valve. In the engine, the valve duration is fixed to a warm-up valve duration ?w in a low-to-middle speed range of the engine during a period from immediately after starting of the engine to when warm-up is completed. In a high speed range, on the other hand, the valve duration is increased from the warm-up valve duration ?w in accordance with increase in the engine speed Ne.

Abstract: An engine adjusts the amount of intake air by cooperative control for the valve duration of the intake valve and the opening degree of the throttle valve. In the engine, the valve duration is fixed to a warm-up valve duration ?w in a low-to-middle speed range of the engine during a period from immediately after starting of the engine to when warm-up is completed. In a high speed range, on the other hand, the valve duration is increased from the warm-up valve duration ?w in accordance with increase in the engine speed Ne.

Abstract: An controller detects a change in a load generation state of an accessory device that generates a load on the internal combustion engine during operation, and the controller in turn controls a variable valve mechanism to change at least one of an operation angle and a valve lift of an intake valve of the internal combustion engine, as well as changing an amount of an intake air drawn into the internal combustion engine, in response to the detected change in the load generation state of the accessory device.

Abstract: If a valve timing adjusting mechanism has a problem, an ECU determines whether or not actual valve timing VTa is larger than valve timing advanced angle limit value VTegr. Depending on the determination, the ECU selects a value for target valve operating angle VLt from safety angles including intermediate valve operating angle VLmid and maximum valve operating angle VLmax. Each of the safety angles VLmid, VLmax is a valve operating angle at which engine combustion is stabilized at the current valve timing. With the valve operating angle fixed at the safety angle VLmid or VLmax, a throttle valve controls intake air amount. This prevents the engine combustion from becoming unstable, thus enabling the engine to be operated in an engine safety mode.

Abstract: An controller detects a change in a load generation state of an accessory device that generates a load on the internal combustion engine during operation, and the controller in turn controls a variable valve mechanism to change at least one of an operation angle and a valve lift of an intake valve of the internal combustion engine, as well as changing an amount of an intake air drawn into the internal combustion engine, in response to the detected change in the load generation state of the accessory device.

Abstract: If a valve timing adjusting mechanism has a problem, an ECU determines whether or not actual valve timing VTa is larger than valve timing advanced angle limit value VTegr. Depending on the determination, the ECU selects a value for target valve operating angle VLt from safety angles including intermediate valve operating angle VLmid and maximum valve operating angle VLmax. Each of the safety angles VLmid, VLmax is a valve operating angle at which engine combustion is stabilized at the current valve timing. With the valve operating angle fixed at the safety angle VLmid or VLmax, a throttle valve controls intake air amount. This prevents the engine combustion from becoming unstable, thus enabling the engine to be operated in an engine safety mode.

Abstract: A combustion condition for each of plural cylinders included in an internal combustion engine is set by the following control that is performed according to an intake air amount in each of the plural cylinders. A reference cylinder is set to a cylinder in which the intake air amount is smallest, and a fuel injection amount for the reference cylinder is set to a fuel injection amount for realizing a stoichiometric air-fuel ratio. The air-fuel ratio in each of the cylinders other than the reference cylinder is set according to the intake air amount in each of the cylinders such that the torque equal to reference torque generated in the reference cylinder is generated. When this setting is performed, air-fuel ratios that are out of a predetermined region in the vicinity of the stoichiometric air-fuel ratio (i.e., air-fuel ratios that are in an avoidance region) are excluded.

Abstract: An intake air amount control apparatus for an internal combustion engine is provided with: an opening control mechanism and a variable valve mechanism, which control an intake air amount; an intake characteristics change mechanism for controlling the intake air amount by adjusting a parameter or parameters different from those of the above two mechanisms; and an intake amount control device for performing a cooperative control of these mechanisms upon the occurrence of any normal condition. The intake air amount control apparatus is also provided with: an abnormality detection device for detecting an abnormal condition in these three mechanisms; and a fail-safe device for controlling the intake air amount of the opening control mechanism out of these three mechanisms and controlling the other two mechanism, so as to fix their control amounts to constant values.