An exhaust gas recirculation valve warming device includes an exhaust throttle arranged in an exhaust passage, an exhaust gas recirculation passage that extends from a portion of the exhaust passage that is upstream of the exhaust throttle and is connected to an intake passage, an exhaust gas recirculation valve arranged in the exhaust gas recirculation passage, and a branch passage that extends from a portion of the exhaust gas recirculation passage that is upstream of the exhaust gas recirculation valve in a direction in which exhaust gas flows, in which the branch passage is connected to a portion of the exhaust passage that is downstream of the exhaust throttle. The exhaust gas recirculation valve includes a valve passage that forms part of the exhaust gas recirculation passage and a warming passage that forms part of the branch passage.

Exhaust gas recirculation pump (30) for an internal combustion engine that includes an electric motor (32) disposed within a housing (36). A Roots device (38) is coupled to the electric motor (32) and includes a housing (40) defining an internal volume (42) in which rotors (44) are disposed and are connected to the electric motor (32). The electric motor housing (36) includes a coolant path (48) formed therein which extends from a coolant inlet (58) to a coolant outlet (78), both coupled to an engine coolant circulation system. The housing includes an oil path (108) formed therein. The oil path includes an oil inlet (110) extending to at least one oil outlet (112). The oil inlet and outlet are coupled to an engine oil circulation system wherein the oil path (108) lubricates bearings (100) and a transmission assembly (46) of the exhaust gas recirculation pump (30).

A method of operating an exhaust gas recirculation pump for an internal combustion engine including: providing an EGR pump assembly including an electric motor coupled to a roots device having rotors, the EGR pump operably connected to an internal combustion engine; providing an EGR control unit lined to the EGR pump assembly; providing sensors linked to the EGR control unit; determining if a motor speed is within a predetermined target (step SI), wherein when the motor speed is within the predetermined target then; determining if a motor torque is within a predetermined target (step S2) wherein when the motor torque is within the predetermined target then; determining if a motor temperature is within a predetermined target (step S3) wherein when the motor temperature is within the predetermined target then; maintaining operation of the exhaust gas recirculation pump.

Methods and systems are provided for diagnosing degradation of an exhaust gas recirculation (EGR) valve. In one example, a method may include, during a vehicle key-off condition, routing compressed air through an EGR passage housing the EGR valve, and indicating degradation of the EGR valve based on a change in an estimated EGR pressure, upon a commanded change in EGR valve position.

An engine system includes an injector, an EGR device (including an EGR valve having a step motor) to recirculate part of exhaust gas of an engine as EGR gas to the engine, and an electronic control unit (ECU) to control the injector, the EGR valve, and others based on an operating state of the engine. The ECU is configured to diagnose foreign-matter lodging abnormality of the EGR valve and a lodged foreign-matter diameter based on detected intake pressure during engine deceleration. When existence of the abnormality and the foreign-matter diameter are determined, the ECU controls the step motor to hold the EGR valve at a first opening degree smaller than a second opening degree needed to remove a foreign matter before fuel cut to the engine by the injector.

A compressor that feeds intake air under pressure is attached to an intake passage of an internal combustion engine. An intercooler that cools intake air is attached to a portion of the intake passage on a downstream side of the compressor. One end of an exhaust gas recirculation passage that allows a part of exhaust air flowing in an exhaust passage to return is connected with the exhaust passage in the internal combustion engine. The other end of the exhaust gas recirculation passage is connected with a portion of the intake passage on an upstream side of the compressor. A dehumidifier that removes moisture contained in gas is attached to a portion of the intake passage from a connecting portion with the exhaust gas recirculation passage through the compressor.

A compressor that feeds intake air under pressure is attached to an intake passage of an internal combustion engine. An intercooler that cools intake air is attached to a portion of the intake passage on a downstream side of the compressor. One end of an exhaust gas recirculation passage that allows a part of exhaust air flowing in an exhaust passage to return is connected with the exhaust passage in the internal combustion engine. The other end of the exhaust gas recirculation passage is connected with a portion of the intake passage on an upstream side of the compressor. A dehumidifier that removes moisture contained in gas is attached to a portion of the intake passage from a connecting portion with the exhaust gas recirculation passage through the compressor.

An exhaust gas recirculation (EGR) control method applied with a humidity sensor for preventing condensation to prevent corrosion caused by exhaust gas in a vehicle, may include a first step of measuring a temperature, humidity, and atmospheric pressure of intake air which is introduced from the outside of the vehicle and flows into the EGR; a second step of determining a molar fraction of water vapor included in the intake air by a combustion equation of the water vapor and determining water vapor pressure in the EGR; and a third step of opening an EGR valve so that EGR gas flows when the water vapor pressure in the EGR is lower than saturated water vapor pressure in the EGR.

An exhaust gas recirculation (EGR) control method applied with a humidity sensor for preventing condensation to prevent corrosion caused by exhaust gas in a vehicle, may include a first step of measuring a temperature, humidity, and atmospheric pressure of intake air which is introduced from the outside of the vehicle and flows into the EGR; a second step of determining a molar fraction of water vapor included in the intake air by a combustion equation of the water vapor and determining water vapor pressure in the EGR; and a third step of opening an EGR valve so that EGR gas flows when the water vapor pressure in the EGR is lower than saturated water vapor pressure in the EGR.

A diesel engine is provided with an EGR line G3 configured to recirculate a portion of exhaust gas, discharged from an engine body 11, to the engine body 11 as combustion gas, an EGR cooler 16 provided in the EGR line G3 and configured to cool exhaust gas by coolant, a coolant supply device configured to supply coolant to the EGR cooler 16, and a control device 30 configured to activate the coolant supply device when the engine body 11 is in operation and a temperature of the engine body 11 is lower or equal to a preset prescribed temperature.