Method and system for operating an engine turbocharger

Abstract

A system and method for operating an engine turbocharger is described. In one example, the turbocharger is rotated in different directions in response to operating conditions. The system and method may reduce engine emissions.

Description

Background technique [0001] It may be desirable to reduce engine emissions when starting the engine so that average engine emissions over the drive cycle may be reduced. One way to improve engine emissions at start-up is to run the engine under rich conditions and supply air to an exhaust system coupled to the engine. Such operation enables engine exhaust components to be oxidized in the exhaust system. In particular, hydrocarbons in the exhaust gas can be oxidized when combined with air introduced into the exhaust system. The oxidized hydrocarbons release heat, which can be transferred to aftertreatment devices in the exhaust system. Heat transfer reduces the amount of time required for the aftertreatment device to reach operating temperature. As a result, the aftertreatment device may begin converting exhaust components to more desirable compounds sooner after engine start, thereby reducing engine emissions. But systems that inject air into the engine exhaust add to syst...

AI Technical Summary

Problems solved by technology

But systems that inject air into the engine exhaust system add to system cost and may be less reliable than systems that do not inject air into the engine exhaust

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