Exhaust heating apparatus for internal combustion engine and control method for the same

Abstract

An exhaust heating apparatus (37) according to the present invention, for heating exhaust being led to an exhaust emission purifier (30) from an internal combustion engine (10) in which a first exhaust turbocharger (28) and a second exhaust turbocharger (29) that is mainly used in a lower rotational speed range of the engine than the first turbocharger are incorporated, is arranged in a first exhaust passage (26f) that is located further upstream than a confluent portion (27c) of the first exhaust passage, which passes through an exhaust turbine (28b) of the first turbocharger and continues to the exhaust emission purifier, and a second exhaust passage (26s), which goes around the exhaust turbine of the first turbocharger and passes through an exhaust turbine (29b) of the second turbocharger and continues to the exhaust emission purifier, and further downstream than the exhaust turbine of the first turbocharger.

Description

TECHNICAL FIELD[0001]The present invention relates to an exhaust heating apparatus that increases a temperature of exhaust in order to activate an exhaust emission purifier and keep the exhaust emission purifier in an activated state in an internal combustion engine that is provided with the exhaust emission purifier.BACKGROUND ART[0002]A turbocharger that comparatively easily achieves an improvement in output from an internal combustion engine also has a tendency at the same time to bring about a drop in fuel efficiency. In recent years, in order to meet the strong demand for an improvement in the fuel efficiency of internal combustion engines in which this kind of turbocharger is incorporated, internal combustion engines in which two turbochargers having different characteristics are incorporated are proposed in Patent Literature 1 and Patent Literature 2. In either case, there are provided a first turbocharger that mainly functions in a low rotational speed range of the internal ...

AI Technical Summary

Benefits of technology

This patent invention is about a new system for heating the exhaust gas in an internal combustion engine. It is possible to use this system in an engine that has two-stage turbochargers. The system can operate at high efficiency in decelerating, accelerating, and constant speed driving. It also uses an oxidation catalyst to further increase the temperature of the heated gas. By adjusting the valves in the exhaust passage, the system can reliably generate stable heated gas and use existing components from the turbochargers. Overall, this invention allows for better control and utilization of exhaust heat in engines.

Problems solved by technology

A turbocharger that comparatively easily achieves an improvement in output from an internal combustion engine also has a tendency at the same time to bring about a drop in fuel efficiency.

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