Smart def injector for low temperature reductant delivery

Abstract

A DEF injector is connected to the exhaust system of a vehicle upstream of an SCR catalyst, and is further connected to the ECU or DCU. An exhaust temperature sensor and an exhaust mass flow rate sensor are connected to the ECU or DCU, and further connected to the DEF injector. The ECU or DCU controls the DEF injector based on exhaust temperature and exhaust mass flow rate when the exhaust temperature is above a certain threshold. The DEF injector itself, or a dedicated DEF injector controller, overrides and / or supplements the control logic located within the ECU or DCU to control the DEF injector to inject DEF at reduced rates when the exhaust temperature and / or the exhaust mass flow rate are lower than the threshold for DEF injection set by the ECU or DCU.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application claims priority to U.S. Provisional No. 62 / 859,372, filed Jun. 10, 2019, the entire contents of all of which are herein incorporated by reference.BACKGROUND[0002]This disclosure relates to a Smart DEF Injector for Low Temperature Reductant Delivery and its method of use. Particularly, this disclosure relates to an arrangement and method for calculating a maximum mass flow rate of DEF that may be injected for a sensed exhaust temperature and exhaust mass flow rate when the exhaust temperatures are below the normal temperature thresholds for DEF dosing.RELATED ART[0003]Diesel engines commonly operate with a lean air to fuel ratio, so that only part of the available oxygen is used in the fuel combustion reaction. While this helps to make diesel engines efficient, it also results in the formation of nitrogen oxides (NOx), an undesirable pollutant, during the combustion process. Presently, the Environmental Protection A...

AI Technical Summary

Benefits of technology

The patent describes a system for reducing emissions in vehicles with a diesel engine. The system includes an engine control unit (ECU) or DCU that controls the engine, an exhaust system, and a selective catalytic reduction (SCR) catalyst. A DEF injector is connected to the exhaust system upstream of the SCR catalyst and is controlled by the ECU or DCU. The system uses exhaust temperature and mass flow rate sensors to control the DEF injector to inject DEF at reduced rates when the exhaust temperature and mass flow rate are lower than a threshold set by the ECU or DCU. The technical effect of this system is to reduce emissions from diesel engines and to help meet stricter emissions regulations.

Problems solved by technology

While this helps to make diesel engines efficient, it also results in the formation of nitrogen oxides (NOx), an undesirable pollutant, during the combustion process.

This, in turn, reduces the amount of NOx formation that takes place within the cylinders, while also reducing overall engine efficiency.

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