Integrated engine and exhaust after treatment system and method of operating same
First Claim
1. An engine system comprising:
- an electronically controlled engine including a plurality of electrical actuators in communication with an electronic engine controller;
an exhaust aftertreatment system fluidly connected to an exhaust outlet from the electronically controlled engine, and including an electronically controlled reductant delivery system in communication with an electronic aftertreatment controller;
the electronic aftertreatment controller being in communication with the electronic engine controller;
the electronic engine controller being operable to control the plurality of electrical actuators responsive to an exhaust control signal from the electronic aftertreatment controller;
the exhaust control signal is based at least in part on a time rate of change of a temperature of engine exhaust in the exhaust aftertreatment system;
wherein the electronic aftertreatment controller includes means for detecting an outgas slip event precondition;
the exhaust control signal is responsive to a detection of the outgas slip event precondition;
wherein the outgas slip event precondition is a reductant slip event precondition;
the exhaust control signal includes a NOx output increase request;
wherein the exhaust aftertreatment system includes in series a diesel particulate filter, the electronically controlled reductant delivery system and a NOx reduction catalyst, and further including a temperature sensor adjacent an outlet of the diesel particulate filter, an engine out NOx sensor, and a SCR out NOx sensor; and
the means for detecting an outgas slip event precondition includes means for comparing a temperature of engine exhaust upstream from a NOx reduction reaction location in an exhaust system to a predetermined temperature;
means for determining whether a time rate of change of a temperature of engine exhaust upstream from a NOx reduction reaction location has exceeded a predetermined temperature change rate for a predetermined duration;
means for comparing the time rate of change of a determined reductant density to a predetermined density change rate; and
means for determining whether the time rate of change of the determined reductant density is positive and the determined reductant density is greater than a predetermined density.
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Accused Products
Abstract
An engine system includes an integrated engine and aftertreatment control system via an electronic aftertreatment controller that is in communication with the electronic engine controller. An aftertreatment control algorithm is operable to generate an exhaust control signal and a reductant dosing control signal. The dosing control signal is used to control a flow rate of a reductant (e.g. urea) injection rate into the exhaust system for facilitating a reduction reaction with NOx in the exhaust flow at a suitable downstream catalyst location. The exhaust control signal is communicated to the electronic engine controller, which responds by altering engine operation to change some aspect of the engine exhaust. In one specific example, an ammonia slip event precondition is detected by the electronic aftertreatment controller, and an exhaust control signal in the form of an increase NOx request is communicated to the engine controller, which responds by altering engine operation to increase NOx output in the hopes of preempting the expected ammonia slip event prior to its actual occurrence to maintain undesirable emissions low at the tailpipe.
38 Citations
1 Claim
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1. An engine system comprising:
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an electronically controlled engine including a plurality of electrical actuators in communication with an electronic engine controller; an exhaust aftertreatment system fluidly connected to an exhaust outlet from the electronically controlled engine, and including an electronically controlled reductant delivery system in communication with an electronic aftertreatment controller; the electronic aftertreatment controller being in communication with the electronic engine controller; the electronic engine controller being operable to control the plurality of electrical actuators responsive to an exhaust control signal from the electronic aftertreatment controller; the exhaust control signal is based at least in part on a time rate of change of a temperature of engine exhaust in the exhaust aftertreatment system; wherein the electronic aftertreatment controller includes means for detecting an outgas slip event precondition; the exhaust control signal is responsive to a detection of the outgas slip event precondition; wherein the outgas slip event precondition is a reductant slip event precondition; the exhaust control signal includes a NOx output increase request; wherein the exhaust aftertreatment system includes in series a diesel particulate filter, the electronically controlled reductant delivery system and a NOx reduction catalyst, and further including a temperature sensor adjacent an outlet of the diesel particulate filter, an engine out NOx sensor, and a SCR out NOx sensor; and the means for detecting an outgas slip event precondition includes means for comparing a temperature of engine exhaust upstream from a NOx reduction reaction location in an exhaust system to a predetermined temperature;
means for determining whether a time rate of change of a temperature of engine exhaust upstream from a NOx reduction reaction location has exceeded a predetermined temperature change rate for a predetermined duration;
means for comparing the time rate of change of a determined reductant density to a predetermined density change rate; and
means for determining whether the time rate of change of the determined reductant density is positive and the determined reductant density is greater than a predetermined density.
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Specification