An engine system includes a throttle device, an EGR valve, and an ECU. The ECU diagnoses foreign-matter lodging abnormality of the EGR valve and the foreign-matter diameter based on intake pressure. When the existence of the abnormality and the foreign-matter diameter are determined, the ECU calculates a difference between a foreign-matter diameter and a predetermined learning determination value as a foreign-matter diameter difference. If this difference is larger than an abnormality determination value, the foreign-matter diameter is judged to be excessive and the throttle device is controlled to avoid engine stall. If the foreign-matter diameter difference is equal to or larger than a normality determination value and also equal to or less than the abnormality determination value, engine deceleration is continued. If the foreign-matter diameter difference is less than the normality determination value, the foreign-matter diameter is judged to be minute and the learning determination value is updated.

Provided is an electronic control device that controls an engine including an EGR system that includes an EGR pipe and an EGR valve disposed in the EGR pipe, an air flow sensor provided in an intake pipe, a throttle valve on a downstream side of the air flow sensor, and an intake pipe pressure sensor that detects an intake pipe pressure. The electronic control device includes a state estimation unit that estimates the intake pipe pressure and an EGR rate based on at least a detection value from the air flow sensor and an EGR valve opening, and an estimation value correction unit that corrects an EGR rate estimation value from the state estimation unit based on a detection value from the intake pipe pressure sensor and an intake pipe pressure estimation value from the state estimation unit.

This EGR system is applied to a vehicle including an exhaust purification device capable of purifying NOx, and is provided with: an EGR passageway; a flow volume modification mechanism; and a control device which, when the NOx concentration in exhaust discharged from the exhaust purification device is greater than a reference value, starts to perform a control process for controlling the flow volume modification mechanism so that the ratio of the flow volume of a first exhaust that flows into a tail pipe decreases and the ratio of the flow volume of a second exhaust that flows into the EGR passageway increases, and makes the ratio of the flow volume of the second exhaust greater than the ratio of the flow volume of the first exhaust during the control process.

Provided is a novel control device of an internal combustion engine capable of estimating an EGR rate in a transient state with high accuracy. Thus, in the present invention, unit spaces are formed by dividing a reference space of the intake passage into a plurality of spaces along a streamline through which the gas mixture of the intake air and the EGR gas flows, a physical model based on an advection equation for estimating the EGR rate of the gas mixture is established so as to correspond to each of the unit spaces, and the EGR rate at which the gas mixture flows into the combustion chamber is estimated by sequentially estimating the EGR rates of the unit spaces connected to head unit spaces from the head unit spaces by the physical model.

Provided is a novel control device of an internal combustion engine capable of estimating an EGR rate in a transient state with high accuracy. Thus, in the present invention, unit spaces are formed by dividing a reference space of the intake passage into a plurality of spaces along a streamline through which the gas mixture of the intake air and the EGR gas flows, a physical model based on an advection equation for estimating the EGR rate of the gas mixture is established so as to correspond to each of the unit spaces, and the EGR rate at which the gas mixture flows into the combustion chamber is estimated by sequentially estimating the EGR rates of the unit spaces connected to head unit spaces from the head unit spaces by the physical model.

This engine system is provided with: an engine; an intake passage; an exhaust passage; an electronic throttle device; an EGR device including an EGR valve; a fresh-air flow device including a fresh-air inflow valve; and an ECU. The ECU, in order to throttle intake air to the engine during deceleration of the engine, causes the electronic throttle device to be closed from an open valve state to a predetermined deceleration opening while causing the EGR valve to become closed to shut off introduction of EGR gas into the intake passage, and, in order to introduce fresh air into the intake passage (intake manifold) downstream of the electronic throttle device, causes the fresh-air inflow valve to become opened from the closed valve state at a timing delayed by a predetermined period from the timing of closing the electronic throttle device.

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.

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.

An engine 1 includes an exhaust manifold, an intake manifold, and an EGR device configured to supply EGR gas from the exhaust manifold to the intake manifold. An upper end of the EGR cooler extended downward is attached to a downwardly extending attachment part provided to the exhaust manifold.

An engine 1 includes an exhaust manifold, an intake manifold, and an EGR device configured to supply EGR gas from the exhaust manifold to the intake manifold. An upper end of the EGR cooler extended downward is attached to a downwardly extending attachment part provided to the exhaust manifold.