Engine exhaust system

Patent metadata

Field	Value
Publication number	US-9995228-B2
Application number	US-201615063673-A
Country	US
Kind code	B2
Filing date	Mar 8, 2016
Priority date	Mar 8, 2016
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

Methods and systems are provided for flowing exhaust gas in an exhaust system of an engine. In one example, a method may include flowing a first portion of exhaust gas to a turbine, from the turbine to at least one aftertreatment device, then from the at least one aftertreatment device to atmosphere, and flowing a second portion of exhaust gas to the at least one aftertreatment device, bypassing the turbine, then from the aftertreatment device to atmosphere, during a second condition. The method may also include, during a second condition, flowing a third portion of exhaust gas to the at least one aftertreatment device, from the at least one aftertreatment device to the turbine, and then from the turbine to atmosphere, and flowing a fourth portion of exhaust gas to the at least one aftertreatment device, and then from the at least one aftertreatment device to atmosphere, bypassing the turbine.

First claim

The invention claimed is:

1. A method for operating an engine, comprising:
during a first operating condition of the engine determined, with an engine controller, based on one or more of a mass airflow sensor, an intake throttle position sensor, and an engine position sensor,
flowing a first portion of exhaust gas from the engine to a turbine via a first three-way valve placed in a third position with the engine controller, the first three-way valve located in a first exhaust passage,
flowing the first portion from the turbine to one or more aftertreatment devices located in a second exhaust passage via a third three-way valve placed in a first position with the controller and a third exhaust passage,
then flowing the first portion from the one or more aftertreatment devices to atmosphere via the second exhaust passage and a second three-way valve placed in a first position with the engine controller, the second three-way valve located in the second passage, and
flowing a second portion of exhaust gas from the engine to the one or more aftertreatment devices in the second exhaust passage via the first exhaust passage, the first three-way valve placed in the third position, and the second exhaust passage, bypassing the turbine, then from the one or more aftertreatment devices to atmosphere via the second passage and the second three-way valve placed in the first position; and
during a second operating condition of the engine determined, with the engine controller, based on one or more of the intake throttle position sensor, the mass airflow sensor, and the engine position sensor,
flowing a third portion of exhaust gas from the engine to the one or more aftertreatment devices in the second exhaust passage via the first exhaust passage, the first three-way valve placed in a second position with the controller, and the second passage,
flowing the third portion from the one or more aftertreatment devices to the turbine via the second passage and the second three-way valve placed in a third position with the controller, and then from the turbine to atmosphere via the third three-way valve placed in a second position with the controller, and
flowing a fourth portion of exhaust gas from the engine to the one or more aftertreatment devices in the second exhaust passage via the first exhaust passage, the first three-way valve placed in the second position, and the second passage, and then from the one or more aftertreatment devices to atmosphere, bypassing the turbine via the second exhaust passage and the second three-way valve placed in the third position.

2. The method of claim 1 , wherein the first operating condition comprises engine load above a first threshold load, and the second operating condition comprises engine load below a second threshold load.

3. The method of claim 1 , further comprising, during engine operation in the first condition or the second condition,
flowing at least a portion of exhaust gas to an intake of the engine via a common exhaust gas recirculation passage and an exhaust gas recirculation valve located in the common exhaust gas recirculation passage,
wherein the common exhaust gas recirculation passage bifurcates into a high pressure exhaust gas recirculation passage and a low pressure exhaust as recirculation passage downstream of the exhaust gas recirculation valve in the direction of exhaust flow, and
wherein the common exhaust gas recirculation passage receives exhaust gas at a location downstream of the turbine in the direction of exhaust flow.

4. The method of claim 3 , further comprising, during the first operating condition, flowing exhaust gas through the common exhaust gas recirculation passage to the high pressure exhaust gas recirculation passage, and from the high pressure exhaust gas recirculation passage to the intake downstream of a compressor; and during the second operating condition, flowing exhaust gas through the common exhaust gas recirculation passage to the low pressure exhaust gas recirculation passage, and from the low pressure exhaust gas recirculation passage to the intake upstream of the compressor.

5. The method of claim 1 , further comprising, responsive to a transition from the first operating condition to the second operating condition, adjusting one or more of an intake throttle valve and an exhaust gas recirculation valve to maintain desired intake air flow.

6. The method of claim 5 , wherein the one or more of the intake throttle valve and the exhaust gas recirculation valve are further adjusted based on boost pressure in the intake, the boost pressure determined with the engine controller.

7. The method of claim 1 , further comprising, during a third operating condition of the engine, flowing all of exhaust gas from the engine through the turbine via the first exhaust passage and the first three-way valve placed in a first position with the controller, from the turbine to the one or more aftertreatment devices in the second exhaust passage via the third three-way valve placed in a first position with the controller, and the third exhaust passage, then from the one or more aftertreatment devices to atmosphere via the second exhaust passage and the second three-way valve placed in the first position, and during a fourth operating condition of the engine, flowing all of the exhaust gas from the engine through the one or more aftertreatment devices, via the first exhaust passage, the first three-way valve placed in the second position, and the second exhaust passage, from the one or more aftertreatment devices to the turbine via the second exhaust passage and the second three-way valve placed in a second position, then from the turbine to atmosphere.

8. The method of claim 7 , wherein the third operating condition comprises an engine acceleration event, the engine acceleration event determined, with the engine controller, based on a pedal position sensor, and the fourth operating condition comprises an engine temperature below a threshold temperature, the engine temperature determined, with the engine controller, based on an engine temperature sensor.

9. A system, comprising:
an engine having an exhaust manifold;
a turbocharger turbine fluidically coupled to the exhaust manifold via a first passage;
a second passage branching off the first passage upstream of the turbine and having an outlet fluidically coupled to the turbine;
a first three-way valve at a junction between the first passage and the second passage;
at least one aftertreatment device positioned in the second passage;
a second three-way valve positioned in the second passage upstream of the turbine and downstream of the at least one aftertreatment device, the second three-way valve coupling the second passage to atmosphere;
a third passage fluidically coupled to an outlet of the turbine and to the second passage upstream of the at least one aftertreatment device;
a third three-way valve coupling the third passage to atmosphere;
a fourth three-way valve coupling a common exhaust gas recirculation (EGR) passage to a low-pressure EGR (LP-EGR) passage and to a high-pressure EGR (HP-EGR) passage;
a mass airflow sensor coupled to an intake of the engine;
an intake throttle position sensor coupled to an intake throttle valve;
an engine position sensor coupled to a crankshaft of the engine; and
a controller receiving signals from the mass airflow sensor, the intake throttle position sensor, and the engine position sensor, the controller storing instructions executable to:
responsive to a first engine operating condition, determined based on indications from one or more of the mass airflow sensor, the intake throttle position sensor, and the engine position sensor, adjust a position of one or more of the firs

Assignees

• Ford Global Tech Llc

Inventors

• Zhang Xiaogang

Classifications

• F02D2041/0017

  by simultaneous control of throttle and exhaust gas recirculation · CPC title

• F02D9/02

  concerning induction conduits (throttle valves, or arrangements thereof in conduits F02D9/08) · CPC title

• F02D41/0007 Primary

  for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12) · CPC title

• F01N13/009

  having two or more separate purifying devices arranged in series · CPC title

• F01N13/10

  of exhaust manifolds {(with cooling jacket F01N3/046)} · CPC title