A water-cooled EGR cooler is to be supplied with exhaust gas from an exhaust line and is to re-circulate the cooled exhaust gas to an intake line. A housing has an exhaust inlet, an exhaust outlet, a coolant inlet, and a coolant outlet. A heat exchange member is disposed in the housing and includes exhaust gas passages from the exhaust inlet to the exhaust outlet at a predetermined interval and also includes a coolant passage through which coolant can flow from the coolant inlet to the coolant outlet between the exhaust gas passages. A pipe member includes a bypass passage formed between an upper surface of the heat exchange member and an inside upper surface of the housing to allow the exhaust gas to bypass the heat exchange member and flow between the upper surface of the heat exchange member and the coolant outlet.

A sensor failure diagnostic apparatus includes a first estimation unit to estimate a mixing ratio of each type of a molecular structure included in a fuel, based on combustion parameters when a combustion of an internal combustion engine is executed in different combustion conditions, among the combustion parameters sensed by a combustion sensor, a second estimation unit to estimate the mixing ratio, based on characteristic parameters sensed by a characteristic sensor, a combustion sensor diagnostic unit to determine whether a failure of the combustion sensor exists, based on a sensed value of the combustion sensor when the combustion is not executed, and a characteristic sensor diagnostic unit to determine whether a failure of the characteristic sensor exists, by comparing the mixing ratio estimated by the first estimation unit with the mixing ratio estimated by the second estimation unit when the combustion sensor diagnostic unit determines the combustion sensor is normal.

An exhaust heat recovery device according to one aspect of the present disclosure includes a main flow path, a secondary flow path, one or a plurality of heat exchangers, and one or a plurality of covering members. Exhaust gas flows in the main flow path. The secondary flow path is a flow path branched from the main flow path and is disposed surrounding a circumference of the main flow path. At least a portion of the exhaust gas flows in the secondary flow path. One or a plurality of the heat exchangers is arranged in the secondary flow path. One or a plurality of the covering members covers at least a portion of a circumference of the heat exchanger, and an internal space constitutes a portion of the secondary flow path. The covering member is provided with an exhaust gas outlet.

An exhaust heat recovery device according to one aspect of the present disclosure includes a main flow path, a secondary flow path, one or a plurality of heat exchangers, and one or a plurality of covering members. Exhaust gas flows in the main flow path. The secondary flow path is a flow path branched from the main flow path and is disposed surrounding a circumference of the main flow path. At least a portion of the exhaust gas flows in the secondary flow path. One or a plurality of the heat exchangers is arranged in the secondary flow path. One or a plurality of the covering members covers at least a portion of a circumference of the heat exchanger, and an internal space constitutes a portion of the secondary flow path. The covering member is provided with an exhaust gas outlet.

A method of controlling engine internal exhaust gas recirculation may include estimating a flow restriction through a diesel particulate filter in an exhaust system of an engine assembly and adjusting a backpressure control valve in the exhaust system downstream of the diesel particulate filter based on the flow restriction. A controlled amount of internal exhaust gas recirculation may be provided to the engine assembly based on adjusting the backpressure control valve.

A method of controlling engine internal exhaust gas recirculation may include estimating a flow restriction through a diesel particulate filter in an exhaust system of an engine assembly and adjusting a backpressure control valve in the exhaust system downstream of the diesel particulate filter based on the flow restriction. A controlled amount of internal exhaust gas recirculation may be provided to the engine assembly based on adjusting the backpressure control valve.

An internal combustion engine has an exhaust gas recirculation system for recirculating exhaust gases from the internal combustion engine into an intake region of the internal combustion engine. The exhaust gas recirculation system includes the following components: at least one exhaust gas cooler through which a first flow path for recirculating exhaust gas extends, having at least one first cooling stage and at least one additional cooling stage, at least one flap arrangement by which the at least one additional cooling stage can be connected, a bypass line through which a second flow path for recirculating exhaust gas extends and by which the exhaust gas cooler can be bypassed during the recirculation of exhaust gas, and an EGR valve having at least three possible positions.

A method and apparatus are disclosed for operating an internal combustion engine equipped with a turbocharger and an exhaust gas recirculation pipe fluidly connecting an exhaust gas line to an air intake duct upstream of a compressor of the turbocharger. A value of a parameter indicative of a temperature of a portion of the exhaust gas recirculation pipe is determined. Exhaust gas recirculation via the exhaust gas recirculation pipe is prevented when the determined value is lower than a predetermined threshold value thereof. The air intake duct portion of compressed air exiting from the compressor is recirculated via the portion of the exhaust gas recirculation pipe.

A method and apparatus are disclosed for operating an internal combustion engine equipped with a turbocharger and an exhaust gas recirculation pipe fluidly connecting an exhaust gas line to an air intake duct upstream of a compressor of the turbocharger. A value of a parameter indicative of a temperature of a portion of the exhaust gas recirculation pipe is determined. Exhaust gas recirculation via the exhaust gas recirculation pipe is prevented when the determined value is lower than a predetermined threshold value thereof. The air intake duct portion of compressed air exiting from the compressor is recirculated via the portion of the exhaust gas recirculation pipe.

A control device for diesel engine controls a diesel engine with a turbo charger that coaxially joins an intake compressor and an exhaust turbine, and drives the intake compressor with energy of exhaust gas which flows into the exhaust turbine to pressurize intake air, and a fresh air/secondary air supply device that supplies fresh air or secondary air to an exhaust passage upstream of the exhaust turbine. The control device for diesel engine includes a gas flow stagnation region determination means that determines whether engine operation conditions or a state of the turbo charger are/is in a gas flow stagnation region, and a fresh air/secondary air supply means that supplies fresh air or secondary air to the exhaust passage upstream of the exhaust turbine by the fresh air/secondary air supply device when the engine operation conditions or the state of the turbo charger are/is in a gas flow stagnation region.