Methods and systems are provided for a single heat exchanger coupled to a main exhaust passage upstream of one or more exhaust catalysts or in between two exhaust catalysts for exhaust heat recovery and exhaust gas recirculation (EGR) cooling. In one example, in the pre-catalyst configuration of the heat exchanger, during exhaust heat recovery, a portion of exhaust may be routed via the heat exchanger while the remaining portion of exhaust may be routed directly to the exhaust catalysts, and fueling may be adjusted on a per-cylinder basis to maintain a target exhaust air-fuel-ratio at the exhaust catalysts.

A gas flow control system is provided for at least one cylinder of an internal combustion of a motor vehicle. The gas flow control system includes a supply passage configured to supply gas to the cylinder and an exhaust gas passage configured to remove gas from the cylinder. A bypass passage is configured to connect the supply passage and exhaust gas passage, and a fluid control switch is selectively operable to supply gas out of the exhaust gas passage through the bypass passage into the supply passage in an exhaust gas return operating mode, and to supply gas out of the supply passage through the bypass passage into the exhaust gas passage in a post-air operating mode.

Methods and systems are provided for an engine. In one example, a method comprises stopping an engine via a soft-stop method in response to a likelihood of condensate forming being less than or equal to a threshold likelihood. The method further comprises stopping the engine via an exhaust gas evacuation method in response to the likelihood of condensate forming being greater than the threshold likelihood.

A basic opening (A0) of an EGR control valve (22) is set, based on a current engine operation state. A differential pressure (P1) across the EGR control valve (22) is calculated, based on an actual exhaust system temperature (T1) sensed by an exhaust temperature sensor (33). A reference differential pressure (P0) is calculated, which is a differential pressure across the EGR control valve (22) in a steady state corresponding to the current engine operation state. A reference pulsation amplitude (D) is calculated, which is an amplitude of pulsation of the reference differential pressure (P0). The basic opening (A0) is corrected, based on the differential pressure (P1), the reference differential pressure (P0), and the reference pulsation amplitude (D).

A control apparatus 1 for the engine includes an ECU. When the operating region of the engine is in the EGR execution region B, the ECU performs the EGR control (step 2), and performs first coolant temperature control for controlling an IC coolant temperature TWic such that the temperature of intake air passing through an intercooler exceeds a dew-point temperature (step 14). Further, in a case where the operating region of the engine is in the EGR stop region C, the ECU performs second coolant temperature control for controlling the IC coolant temperature TWic such that the temperature of intake air having passed through the intercooler exceeds the dew-point temperature, assuming that the operating region of the engine has shifted to the EGR execution region B (step 17).

A basic opening (A0) of an EGR control valve (22) is set, based on a current engine operation state. A differential pressure (P1) across the EGR control valve (22) is calculated, based on an actual exhaust system temperature (T1) sensed by an exhaust temperature sensor (33). A reference differential pressure (P0) is calculated, which is a differential pressure across the EGR control valve (22) in a steady state corresponding to the current engine operation state. A reference pulsation amplitude (D) is calculated, which is an amplitude of pulsation of the reference differential pressure (P0). The basic opening (A0) is corrected, based on the differential pressure (P1), the reference differential pressure (P0), and the reference pulsation amplitude (D).

A recirculation valve of an exhaust gas recirculation apparatus includes: a valve housing having a gas inlet into which a recirculation gas flows, a gas outlet from which the recirculation gas is discharged, and an intermediate inlet disposed between the gas inlet and the gas outlet; and a valve body selectively opening and closing the gas inlet and the intermediate inlet.

A boosted engine is provided, which includes an engine body formed with a combustion chamber, a spark plug, a fuel injection valve, a booster, a boost controller, and a control unit including an operating range determining module and a compression end temperature estimating module. In a high load range, the fuel injection valve and the spark plug are controlled so that a mixture gas inside the combustion chamber starts combustion through flame propagation by ignition of the spark plug, and unburned mixture gas then combusts by compression ignition, and the boost controller is controlled to bring the booster into a boosting state. When a gas temperature inside the combustion chamber exceeds a given temperature at CTDC, the fuel injection valve is controlled so that a fuel injection end timing occurs on a compression stroke, and the spark plug is controlled so that the mixture gas is ignited after CTDC.

In a valve device (1), when a valve (33) is closed, an output shaft of an actuator unit (10) is connected to the valve (33). A control unit of the valve device (1) determines a control constant to be a value by which a response speed of the actuator unit (10) is smaller as ambient temperature is higher, and performs feedback control.

Methods and systems are provided for a heat exchanger. In one example, a method may include adjusting a flap to adjust a number of conduits configured to receive exhaust gas recirculate and exhaust gas within the heat exchanger.