Abstract: In an engine, an intake duct is provided with an intercooler disposed downstream of an intake air compressor. An EGR pipe is provided with an EGR valve and an EGR cooler. An ECU determines a generation of a condensed water in the EGR cooler, the generation of the condensed water in a merging portion where a fresh air and an EGR gas merge with each other, and the generation of the condensed water in the intercooler. When it is determined that the condensed water is generated in any of these portions, the ECU performs a corresponding countermeasure for restricting the generation of the condensed water.

Abstract: A low temperature cooling device applied to an internal combustion engine includes an EGR device, a low temperature coolant circuit, a prediction unit predicting whether an EGR cooler falls into a state where a cooling performance falls short according to at least one of an operating state of an internal combustion engine and an outside air environment while a control that dehumidifies an EGR gas by cooling the EGR gas in the EGR cooler is performed, and a control unit performing at least one of a first increase control that increases a flow rate of a coolant flowing into the EGR cooler, a second increase control that increases an air rate of a radiator fan cooling a radiator, and an inhibition control that inhibits the EGR gas from flowing back when the prediction unit predicts that the EGR cooler falls into the state where the cooling performance falls short.

Abstract: In an engine, an intake duct is provided with an intercooler disposed downstream of an intake air compressor. An EGR pipe is provided with an EGR valve and an EGR cooler. An ECU determines a generation of a condensed water in the EGR cooler, the generation of the condensed water in a merging portion where a fresh air and an EGR gas merge with each other, and the generation of the condensed water in the intercooler. When it is determined that the condensed water is generated in any of these portions, the ECU performs a corresponding countermeasure for restricting the generation of the condensed water.

Abstract: In an engine, an intake duct is provided with an intercooler disposed downstream of an intake air compressor. An EGR pipe is provided with an EGR valve and an EGR cooler. An ECU determines a generation of a condensed water in the EGR cooler, the generation of the condensed water in a merging portion where a fresh air and an EGR gas merge with each other, and the generation of the condensed water in the intercooler. When it is determined that the condensed water is generated in any of these portions, the ECU performs a corresponding countermeasure for restricting the generation of the condensed water.

Abstract: A low temperature cooling device applied to an internal combustion engine includes an EGR device, a low temperature coolant circuit, a prediction unit predicting whether an EGR cooler falls into a state where a cooling performance falls short according to at least one of an operating state of an internal combustion engine and an outside air environment while a control that dehumidifies an EGR gas by cooling the EGR gas in the EGR cooler is performed, and a control unit performing at least one of a first increase control that increases a flow rate of a coolant flowing into the EGR cooler, a second increase control that increases an air rate of a radiator fan cooling a radiator, and an inhibition control that inhibits the EGR gas from flowing back when the prediction unit predicts that the EGR cooler falls into the state where the cooling performance falls short.

Abstract: A low temperature cooling device applied to an internal combustion engine includes an EGR device returning a part of an exhaust gas of an internal combustion engine to an intake passage as an EGR gas, a low temperature coolant circuit circulating a coolant through an intercooler cooling an intake gas of the internal combustion engine and an EGR cooler cooling the EGR gas, a flow rate control valve regulating a flow rate ratio between the coolant flowing into the intercooler and the coolant flowing into the EGR cooler, and a control unit varying the flow rate ratio between the coolant flowing into the intercooler and the coolant flowing into the EGR cooler by controlling the flow rate control valve according to an outside air environment and an operating state of the internal combustion engine.

Abstract: A cylinder-inflow EGR gas amount is estimated, a misfire limit EGR gas amount is calculated on the basis of an engine operation state, and the misfire limit EGR gas amount is compared with the cylinder-inflow EGR gas amount to predict whether a misfire occurs. When the misfire is predicted, a misfire avoidance control is executed. Further, an actual misfire countermeasure effect amount in a case of the execution of the misfire avoidance control is calculated, and the actual misfire countermeasure effect amount is compared with a required misfire countermeasure effect amount to determine whether the misfire is avoidable when the misfire avoidance control is executed. If the misfire is unavoidable even if the misfire avoidance control is executed, a delay restriction value of an ignition timing to avoid the misfire is calculated, and the amount of a delay in the ignition timing is restricted using the delay restriction value.

Abstract: An ejector used in an EGR system is disposed at a position at which at least part of an outer-diameter-gradually-varying portion of a nozzle can be viewed through an introduction hole from the outside of the housing. Consequently, EGR gas introduced into the housing through the introduction hole is introduced into a decompression chamber without colliding with an outer wall of an outer-diameter equivalent portion of the nozzle. The outer-diameter-gradually-varying portion of the nozzle guides the EGR gas from the introduction hole, so that the EGR gas can be efficiently mixed with an air flow of compressed air supplied from an air compressor.

Abstract: In an engine, an intake duct is provided with an intercooler disposed downstream of an intake air compressor. An EGR pipe is provided with an EGR valve and an EGR cooler. An ECU determines a generation of a condensed water in the EGR cooler, the generation of the condensed water in a merging portion where a fresh air and an EGR gas merge with each other, and the generation of the condensed water in the intercooler. When it is determined that the condensed water is generated in any of these portions, the ECU performs a corresponding countermeasure for restricting the generation of the condensed water.

Abstract: While an engine is an idling state and an EGR opening degree is increased stepwise from a specified opening degree, a variation in engine speed (a standard deviation in engine speed) is repeatedly computed. After that, a specified step amount is successively reduced from the EGR opening degree and the variation in engine speed is successively computed until the EGR opening degree becomes less than or equal to a specified value. Then, a maximum value of the EGR opening degrees where the variation in engine speed becomes minimum is learned as the full-close position.

Abstract: When the engine is in a specified operation state in which the EGR valve is brought into the full-close condition, the holding force for holding the EGR valve at the full-close position is corrected by correcting the control duty signal of the EGR valve. The control duty signal is corrected according to the target valve overlap quantity or the target phase of the valve timing. Thus, even when a proper holding force of the EGR valve is varied due to a variation in differential pressure between the intake pressure and the exhaust pressure, the holding force of the EGR valve is corrected to be a proper holding force.

Abstract: A cylinder-inflow EGR gas quantity determining arrangement estimates or senses a value of a cylinder-inflow EGR gas quantity, which is a quantity of EGR gas that flows into a cylinder of an internal combustion engine. A misfire predicting arrangement predicts whether misfire occurs based on the value of the cylinder-inflow EGR gas quantity and an operational state of the internal combustion engine. A misfire-avoidance control arrangement executes at least one misfire-avoidance control operation to avoid the misfire when the misfire predicting arrangement predicts that the misfire occurs.

Abstract: When a constant driving voltage is applied to a motor driving an EGR valve so that the EGR opening degree is varied, an angular speed of the EGR valve becomes minimal at a position where the driving torque of the EGR valve becomes maximal. In view of this, while an opening degree of the EGR valve is varied with a constant driving voltage applied to the motor, the EGR opening degree where the angular speed becomes minimal is learned as a full-close position.

Abstract: An intake air quantity information determining arrangement senses or computes one of an intake air quantity and a torque of an internal combustion engine as intake air quantity information. A misfire-avoidance control arrangement executes a misfire-avoidance control operation, which avoids misfire by controlling a throttle opening degree of a throttle valve such that a value of the intake air quantity information does not decrease below a normal combustion threshold value.

Abstract: While an engine is at idling state with an EGR valve fully closed, an EGR controller estimates a leak quantity of an exhaust gas flowing into an intake passage and performs a biasing-force-increase control in which the EGR valve is biased toward a full-close position. When the leak quantity of the exhaust gas is greater than or equal to a specified value, the controller executes an abutting control in which the EGR valve is opened and closed multiple times so that the EGR valve is brought into contact with a valve seat multiple times after the engine is shut down.

Abstract: When the engine is in a specified operation state in which the EGR valve is brought into the full-close condition, the holding force for holding the EGR valve at the full-close position is corrected by correcting the control duty signal of the EGR valve. The control duty signal is corrected according to the target valve overlap quantity or the target phase of the valve timing. Thus, even when a proper holding force of the EGR valve is varied due to a variation in differential pressure between the intake pressure and the exhaust pressure, the holding force of the EGR valve is corrected to be a proper holding force.

Abstract: An intake air quantity information determining arrangement senses or computes one of an intake air quantity and a torque of an internal combustion engine as intake air quantity information. A misfire-avoidance control arrangement executes a misfire-avoidance control operation, which avoids misfire by controlling a throttle opening degree of a throttle valve such that a value of the intake air quantity information does not decrease below a normal combustion threshold value.

Abstract: A cylinder-inflow EGR gas amount is estimated, a misfire limit EGR gas amount is calculated on the basis of an engine operation state, and the misfire limit EGR gas amount is compared with the cylinder-inflow EGR gas amount to predict whether a misfire occurs. When the misfire is predicted, a misfire avoidance control is executed. Further, an actual misfire countermeasure effect amount in a case of the execution of the misfire avoidance control is calculated, and the actual misfire countermeasure effect amount is compared with a required misfire countermeasure effect amount to determine whether the misfire is avoidable when the misfire avoidance control is executed. If the misfire is unavoidable even if the misfire avoidance control is executed, a delay restriction value of an ignition timing to avoid the misfire is calculated, and the amount of a delay in the ignition timing is restricted using the delay restriction value.

Abstract: When a constant driving voltage is applied to a motor driving an EGR valve so that the EGR opening degree is varied, an angular speed of the EGR valve becomes minimal at a position where the driving torque of the EGR valve becomes maximal. In view of this, while an opening degree of the EGR valve is varied with a constant driving voltage applied to the motor, the EGR opening degree where the angular speed becomes minimal is learned as a full-close position.

Abstract: While an engine is an idling state and an EGR opening degree is increased stepwise from a specified opening degree, a variation in engine speed (a standard deviation in engine speed) is repeatedly computed. After that, a specified step amount is successively reduced from the EGR opening degree and the variation in engine speed is successively computed until the EGR opening degree becomes less than or equal to a specified value. Then, a maximum value of the EGR opening degrees where the variation in engine speed becomes minimum is learned as the full-close position.