In an EGR system, a quantity of exhaust gas passing through an EGR valve is computed by an EGR valve model simulating a behavior of the recirculated exhaust gas passing through the EGR valve. An exhaust gas quantity flowing into a cylinder is computed by an EGR-gas-delay model simulating a behavior of the exhaust gas passing through the EGR valve and the throttle valve and then flows into a cylinder. The EGR-gas-delay model includes a confluent-delay model simulating a behavior of EGR gas passing thorough the EGR valve and flowing into the intake passage upstream of the throttle valve; an intake-pipe-delay model simulating a behavior of EGR gas flowing in the intake passage and passing through the throttle valve; and an intake-manifold-delay model simulating a behavior of EGR gas which passes through the throttle valve and then flows into the intake passage downstream of the throttle valve.

Active control of one or more exhaust gas recirculation loops is provided to manage and EGR fraction in the charge flow to produce desired operating conditions and/or provide diagnostics in response to at least one of an oxygen concentration and a NOx concentration in the charge flow and in the exhaust flow.

Active control of one or more exhaust gas recirculation loops is provided to manage and EGR fraction in the charge flow to produce desired operating conditions and/or provide diagnostics in response to at least one of an oxygen concentration and a NOx concentration in the charge flow and in the exhaust flow.

An engine having a low pressure EGR system includes: an intake line suctioning outdoor air and transferring the outdoor air to a combustion chamber; a turbocharger actuated by exhaust gas which flows in an exhaust line to compress gas which flows in the intake line; a supercharger installed at a downstream side of the turbocharger; a low pressure EGR line branched at one side of the exhaust line and joined to an upstream side of the turbocharger to recirculate the exhaust gas; a recirculation line branched on the intake line at a downstream side of the supercharger and joined to the intake line at an upstream side of a point where the low EGR line and the intake line meet; and a control unit controlling the actuation of the supercharger. The control unit actuates the supercharger in the case of a coasting driving condition.

An engine having a low pressure EGR system includes: an intake line suctioning outdoor air and transferring the outdoor air to a combustion chamber; a turbocharger actuated by exhaust gas which flows in an exhaust line to compress gas which flows in the intake line; a supercharger installed at a downstream side of the turbocharger; a low pressure EGR line branched at one side of the exhaust line and joined to an upstream side of the turbocharger to recirculate the exhaust gas; a recirculation line branched on the intake line at a downstream side of the supercharger and joined to the intake line at an upstream side of a point where the low EGR line and the intake line meet; and a control unit controlling the actuation of the supercharger. The control unit actuates the supercharger in the case of a coasting driving condition.

Methods and systems are provided for exhaust gas heat recovery at a split exhaust gas heat exchanger. Exhaust gas may flow in both directions through an exhaust bypass passage and the heat exchanger coupled to the bypass passage. Warm or cold EGR may be delivered from the exhaust passage to the engine intake manifold and heat from the exhaust gas may be recovered at the heat exchanger.

An Exhaust Gas Recirculation (EGR) Valve is disclosed including a housing having a first side configured to be coupled with a fresh air inlet, a second side configured to be coupled with an outlet, and an exhaust-gas inlet defined at a bottom of the housing. The housing may include one or more inner surfaces defining at least one path to direct a condensate, when present at any point on a bottom surface of an inside of the housing, to a low point within the housing directed by gravity. The outlet may be configured to be fluidically coupled with a turbo compressor.

An Exhaust Gas Recirculation (EGR) Valve is disclosed including a housing having a first side configured to be coupled with a fresh air inlet, a second side configured to be coupled with an outlet, and an exhaust-gas inlet defined at a bottom of the housing. The housing may include one or more inner surfaces defining at least one path to direct a condensate, when present at any point on a bottom surface of an inside of the housing, to a low point within the housing directed by gravity. The outlet may be configured to be fluidically coupled with a turbo compressor.

An EGR valve is provided in an EGR passage circulating a part of an exhaust gas of an exhaust pipe in an intake pipe as an EGR gas, the EGR valve adjusting an EGR gas amount flowing in the EGR passage when an engine is in an EGR region, a differential pressure device is provided in the intake pipe, the differential pressure device adjusting a differential pressure of the EGR valve, a control unit is provided to control the EGR valve and the differential pressure device, and the EGR control method includes switching whether to adjust the EGR gas amount using the EGR valve and the differential pressure device or to adjust the EGR gas amount using the EGR valve only on the basis of an exhaust gas pressure of an inlet portion of the EGR passage.

An EGR valve is provided in an EGR passage circulating a part of an exhaust gas of an exhaust pipe in an intake pipe as an EGR gas, the EGR valve adjusting an EGR gas amount flowing in the EGR passage when an engine is in an EGR region, a differential pressure device is provided in the intake pipe, the differential pressure device adjusting a differential pressure of the EGR valve, a control unit is provided to control the EGR valve and the differential pressure device, and the EGR control method includes switching whether to adjust the EGR gas amount using the EGR valve and the differential pressure device or to adjust the EGR gas amount using the EGR valve only on the basis of an exhaust gas pressure of an inlet portion of the EGR passage.