Systems and methods for operating an internal combustion engine based on output of an intake manifold pressure sensor and output of an in cylinder pressure sensor are described. The systems and methods provide a way of determining cylinder air charge so that a fuel injector has sufficient time to provide a desired amount of fuel to a cylinder during a cycle of the cylinder.

A fuel injection amount control device controls a fuel injection amount of an injector in an internal combustion engine including a blow-by gas ventilation system. The fuel injection amount control device includes a reflection rate setting section, a dilution correction section, and a dilution learning section. The reflection rate setting section sets a reflection rate proportional to the amount of a blow-by gas discharged to an intake air. The dilution correction section corrects a fuel injection amount by using, as a correction value, the product obtained by multiplying a reflection rate by a dilution learning value. The dilution learning section updates the dilution learning value such that an air-fuel ratio F/B correction value approaches 0 on the condition that a fuel dilution amount of engine oil is equal to or greater than a predetermined value.

An object of the present invention is to predict change of a combustion limit due to cycle variation of temperature and an EGR ratio and perform correction every cycle to decrease an amount of combustion consumption. Therefore, in an internal combustion engine control device that controls an internal combustion engine including a cylinder and an exhaust pipe, the internal combustion engine control device includes a control unit configured to perform EGR control of controlling an exhaust gas in the exhaust pipe to return to an inner cylinder of the cylinder, obtain temperature of the gas in the internal cylinder and an EGR ratio in a state where both an intake valve and an exhaust valve are closed in an combustion cycle, and correct a combustion parameter in a same combustion cycle as the combustion cycle on the basis of the obtained gas temperature and the obtained EGR ratio.

A control apparatus and a control method for an internal combustion engine of the present invention integrates an operating time in a state in which temperature TCAT of an exhaust gas purification catalyst is lower than a first temperature, to obtain first integrated time IT1, senses oxygen storage capacity OSC of the exhaust gas purification catalyst, and has a regeneration treatment of sulfur poisoning carried out when first integrated time IT1 exceeds first time THT1 and oxygen storage capacity OSC falls below first capacity OSC1, and furthermore, integrates an operating time in a state in which temperature TCAT of the exhaust gas purification catalyst is higher than second temperature TCAT2, to obtain second integrated time IT2, and has a regeneration treatment of oxidation poisoning carried out when second integrated time IT2 exceeds second time THT2.

A fuel injection control apparatus of an internal combustion engine, which can appropriately control the amount of fuel injection from an in-cylinder injection valve so as to achieve a desired air-fuel ratio, regardless of the operating state of the internal combustion engine, is provided. The fuel injection control apparatus comprises: an additional injection means which, when determining that the operating state of the internal combustion engine is a transient state, allows the in-cylinder injection valve to inject a fuel amount conformed to a changing intake air amount; and a subtraction means for subtracting a minimum fuel amount, injectable from the in-cylinder injection valve, from a fuel amount to be injected, before injection by the additional injection means is performed.

A flow rate detector includes a detection circuit, which is configured to output as an analog signal a voltage in accordance with a flow rate of air flowing through an intake pipe, and a conversion circuit, which is configured to convert the analog signal input from the detection circuit to a digital signal based on an analog-to-digital conversion characteristic to output the digital signal. The analog signal that corresponds to a forward flow direction and is input to the conversion circuit is set to have a value larger than an input voltage range in which a missing code may occur in the analog-to-digital conversion characteristic.

A combustion control method and a combustion control system with variable excess air coefficient for gasoline engine are provided. The combustion control method with variable excess air coefficient for gasoline engine comprises steps as follows: monitoring engine operating condition; determining current engine load condition based on the engine operating condition, wherein the engine load condition comprises part load, high load, and full load conditions; and selecting an appropriate excess air coefficient combustion mode in accordance with the current engine load condition; wherein the engine uses lean combustion mode with excess air coefficient of 1.62.0 when the current engine load condition is the part load condition; the engine uses combustion mode with excess air coefficient of 1 when the current engine load condition is the high load condition; and the engine uses combustion mode with excess air coefficient of 0.80.9 when the current engine load condition is the full load condition.

An intake pressure sensor is provided in an intake path of a single cylinder engine and detects an intake pressure. A crank angle sensor detects a crank angle of the single cylinder engine. A sampling unit samples the intake pressure detected by the intake pressure sensor when the crank angle detected by the crank angle sensor becomes a sampling start angle. A calculation unit extracts M intake pressures of relatively small values of N intake pressures sampled by the sampling unit. The calculation unit acquires, as a bottom pressure, an average value of P intake pressures remaining after several intake pressures of relatively large values and several intake pressures of relatively small values of the M intake pressures are excluded.

A control apparatus (12): creates a torque correction table indicating a relationship between a change rate of an intake air amount, a change of the main injection amount and the main injection timing of a fuel injection apparatus (8) in the torque value of a diesel engine (1) in a lean state; measures an intake air amount in a rich state by using an MAF sensor (11); calculates a change rate of the measured intake air amount for the intake air amount in the lean state; obtains a correction value of the main injection amount and a correction value of the main injection timing of the fuel injection apparatus (8) based on the calculated change rate and the torque correction table; and performs an injection of the fuel in the rich state at the main injection amount and the main injection timing, corrected by the respective correction values.

The object of the invention is to obtain a thermal flowmeter which effectively causes water droplets to be directed to a discharge port when the water droplets adhered to a wall surface of a first passage are drawn into a third passage portion. A thermal flowmeter of the present invention includes a sub-passage that takes a measurement gas flowing through a main passage; and a flow detection unit that measures a flow rate of the measurement gas by performing heat transfer with the measurement gas flowing through a sub-passage. Further, the sub-passage includes a first passage, a second passage portion branching in the middle of the first passage portion to be directed toward the flow detection unit; and a third passage portion branching in the middle of the second passage portion to be directed toward a third outlet, and a pressure loss generation means is provided between a third inlet and the third outlet of the third passage portion.