A control device for an internal combustion engine is provided. The internal combustion engine includes a cylinder, an in-cylinder pressure sensor, a fuel injection valve, and an alcohol concentration sensor. The control device includes an electronic control unit. The electronic control unit is configured to: carry out learning of fuel properties with the fuel injected from the fuel injection valve as a target; calculate a combustion speed parameter, showing a combustion speed, within the cylinder, of the fuel that is a learning target of the fuel properties, on a basis of the in-cylinder pressure; and determine that water is included in the fuel when the capacitance of the fuel detected by the alcohol concentration sensor is larger than a preset first threshold, and when the combustion speed of the fuel within the cylinder is smaller than a preset second threshold.

A control device for an internal combustion engine is provided. The internal combustion engine includes a cylinder, an in-cylinder pressure sensor, a fuel injection valve, and an alcohol concentration sensor. The control device includes an electronic control unit. The electronic control unit is configured to: carry out learning of fuel properties with the fuel injected from the fuel injection valve as a target; calculate a combustion speed parameter, showing a combustion speed, within the cylinder, of the fuel that is a learning target of the fuel properties, on a basis of the in-cylinder pressure; and determine that water is included in the fuel when the capacitance of the fuel detected by the alcohol concentration sensor is larger than a preset first threshold, and when the combustion speed of the fuel within the cylinder is smaller than a preset second threshold.

An exhaust gas recirculation system for an engine includes a conduit, and a U-shaped exhaust gas mixer. The conduit is configured to direct an exhaust gas away from an exhaust manifold. The U-shaped exhaust gas mixer is configured to direct exhaust gas from the conduit and into an engine air intake system. The U-shaped exhaust gas mixer is arranged with a pre-mixing cavity configured to disperse the exhaust gas and entraining the exhaust gas into an intake air flow prior to distribution into an intake manifold of an engine.

An exhaust gas recirculation system for an engine includes a conduit, and a U-shaped exhaust gas mixer. The conduit is configured to direct an exhaust gas away from an exhaust manifold. The U-shaped exhaust gas mixer is configured to direct exhaust gas from the conduit and into an engine air intake system. The U-shaped exhaust gas mixer is arranged with a pre-mixing cavity configured to disperse the exhaust gas and entraining the exhaust gas into an intake air flow prior to distribution into an intake manifold of an engine.

A self-propelled construction device, in particular a soil compactor, includes a turbocharged diesel engine with a first radiator arrangement for cooling charge air and a second radiator arrangement for cooling a cooling liquid and/or hydraulic oil, with a first radiator fan being allocated to the first radiator arrangement and a second radiator fan being allocated to the second radiator arrangement and the first radiator fan and the second radiator fan being able to be operated essentially independently from each other.

A self-propelled construction device, in particular a soil compactor, includes a turbocharged diesel engine with a first radiator arrangement for cooling charge air and a second radiator arrangement for cooling a cooling liquid and/or hydraulic oil, with a first radiator fan being allocated to the first radiator arrangement and a second radiator fan being allocated to the second radiator arrangement and the first radiator fan and the second radiator fan being able to be operated essentially independently from each other.

An exhaust gas recirculation system for an engine includes a conduit, and a U-shaped exhaust gas mixer. The conduit is configured to direct an exhaust gas away from an exhaust manifold. The U-shaped exhaust gas mixer is configured to direct exhaust gas from the conduit and into an engine air intake system. The U-shaped exhaust gas mixer is arranged with a pre-mixing cavity configured to disperse the exhaust gas and entraining the exhaust gas into an intake air flow prior to distribution into an intake manifold of an engine.

An exhaust gas recirculation system for an engine includes a conduit, and a U-shaped exhaust gas mixer. The conduit is configured to direct an exhaust gas away from an exhaust manifold. The U-shaped exhaust gas mixer is configured to direct exhaust gas from the conduit and into an engine air intake system. The U-shaped exhaust gas mixer is arranged with a pre-mixing cavity configured to disperse the exhaust gas and entraining the exhaust gas into an intake air flow prior to distribution into an intake manifold of an engine.

A filter (30) traps particulate matter in an exhaust gas. A filter inlet side pressure sensor (34) is provided in an inlet side of the filter (30). An EGR valve inlet side pressure sensor (22) is provided in an inlet side of an EGR valve (20). A regeneration controller (38C) determines whether or not the filter inlet side pressure sensor (34) is in failure based upon a difference between a pressure value detected by the filter inlet side pressure sensor (34) and a pressure value detected by the EGR valve inlet side pressure sensor (22). When the filter inlet side pressure sensor (34) is in failure, the regeneration controller (38C) performs control of regeneration treatment using a differential pressure calculated based upon a pressure value detected by the EGR valve inlet side pressure sensor (22) and a pressure value detected by the filter outlet side pressure sensor (35).

Various methods and arrangements for improving fuel economy in decel fuel cut-off (DFCO) operation of an internal combustion engine are described. In one aspect, a catalytic converter bypass valve diverts the pumped air in DFCO mode from flowing through a catalytic converter. The diverted, pumped air may flow through a bypass line or be returned to the engine intake manifold through an exhaust gas recirculation return line. Another aspect of the invention relates to directing the diverted pumped air through an emission control device.