Engine control systems and methods for nitrogen oxide reduction

• US 10,077,727 B2
• Filed: 01/13/2016
• Issued: 09/18/2018
• Est. Priority Date: 01/13/2016
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Sczomak, David P., Gallon, Robert J., McAlpine, Robert S., Solomon, Arun S.
• Primary Examiner(s): Bogue, Jesse
• Application Number:
  US14/994,531
• Publication Number:
  US 20170198652A1
• Time in Patent Office: 979 Days
• CPC Class Codes: F01N 2430/02 by cutting out a part of engine cylinders
• CPC Class Codes: F01N 2610/02 the substance being ammonia or urea
• CPC Class Codes: F01N 2900/08 said parameters being related to the engine
• CPC Class Codes: F01N 2900/1614 NOx amount trapped in catalyst
• CPC Class Codes: F01N 2900/1622 Catalyst reducing agent absorption capacity or consumption amount
• CPC Class Codes: F01N 2900/1818 Concentration of the reducing agent
• CPC Class Codes: F01N 3/0814 combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts
• CPC Class Codes: F01N 3/0842 Nitrogen oxides
• CPC Class Codes: F01N 3/2066 Selective catalytic reduction [SCR]
• CPC Class Codes: F02D 13/00 Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
• CPC Class Codes: F02D 13/06 Cutting-out cylinders
• CPC Class Codes: F02D 2041/0012 with selective deactivation of cylinders
• CPC Class Codes: F02D 2200/0806 NOx storage amount, i.e. amount of NOx stored on NOx trap
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/0275 the exhaust gas treating apparatus being a NOx trap or adsorbent
• CPC Class Codes: F02D 41/3005 Details not otherwise provided for
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A fuel control module controls fuel injection of an engine based on a predetermined lean air/fuel ratio. The predetermined lean air/fuel ratio is fuel lean relative to a stoichiometric air/fuel ratio for the fuel. A cylinder control module selectively deactivates opening of intake and exhaust valves of M cylinders of the engine to increase removal of nitrogen oxide (NOx) from exhaust. M is an integer greater than 0 and less than a total number of cylinders of the engine. The fuel control module further: disables fueling of the M cylinders while opening of the intake and exhaust valves of the M cylinders is deactivated; and, while fueling of the M cylinders is disabled and opening of the intake and exhaust valves of the M cylinders is deactivated, controls fuel injection of other cylinders based on a predetermined rich air/fuel ratio that is fuel rich relative to the stoichiometric air/fuel ratio.

Claims

1. An engine control system, comprising:

a fuel control module that controls fuel injection of an engine based on a predetermined lean air/fuel ratio, wherein the predetermined lean air/fuel ratio is fuel lean relative to a stoichiometric air/fuel ratio for the fuel; and

a cylinder control module that deactivates opening of intake and exhaust valves of M cylinders of the engine to facilitate removal of nitrogen oxide (NOx) from exhaust in response to a determination that;

an amount of ammonia stored by a selective catalytic reduction (SCR) catalyst receiving exhaust output by the engine is less than a first predetermined amount of ammonia;

an engine speed is within a predetermined speed range for facilitating the removal of NOx; and

an engine load is within a predetermined engine load range for facilitating the removal of NOx,

wherein M is an integer greater than 0 and less than a total number of cylinders of the engine,

wherein the fuel control module further;

disables fueling of the M cylinders while opening of the intake and exhaust valves of the M cylinders is deactivated; and

while fueling of the M cylinders is disabled and opening of the intake and exhaust valves of the M cylinders is deactivated, controls fuel injection of other cylinders of the engine based on a predetermined rich air/fuel ratio that is fuel rich relative to the stoichiometric air/fuel ratio for the fuel;

wherein the cylinder control module further re-activates opening of the intake and exhaust valves of the M cylinders in response to a determination that;

the amount of ammonia stored by SCR catalyst is greater than a second predetermined amount of ammonia, wherein the second predetermined amount of ammonia is greater than the first predetermined amount of ammonia; and

the engine load is increasing;

wherein the fuel control module further controls fuel injection of the M cylinders after the re-activation based on the predetermined lean air/fuel ratio in response to the determination that;

the amount of ammonia stored by SCR catalyst is greater than the second predetermined amount of ammonia; and

the engine load is increasing;

wherein the cylinder control module further continues to deactivate the opening of the intake and exhaust valves of the M cylinders of the engine in response to a determination that;

the amount of ammonia stored by SCR catalyst is greater than the second predetermined amount of ammonia; and

the engine load is not increasing; and

wherein, during the continued deactivation, the fuel control module further controls the fuel injection of the other cylinders based on the predetermined lean air/fuel ratio in response to the determination that;

the amount of ammonia stored by SCR catalyst is greater than the second predetermined amount of ammonia; and

the engine load is not increasing.

2. The engine control system of claim 1 wherein M is equal to one-half of the total number of cylinders of the engine.

3. An engine control method, comprising:

controlling fuel injection of an engine based on a predetermined lean air/fuel ratio, wherein the predetermined lean air/fuel ratio is fuel lean relative to a stoichiometric air/fuel ratio for the fuel;

deactivating opening of intake and exhaust valves of M cylinders of the engine to facilitate removal of nitrogen oxide (NOx) from exhaust in response to a determination that;

an amount of ammonia stored by a selective catalytic reduction (SCR) catalyst receiving exhaust output by the engine is less than a first predetermined amount of ammonia;

an engine speed is within a predetermined speed range for facilitating the removal of NOx; and

an engine load is within a predetermined engine load range for facilitating the removal of NOx,

wherein M is an integer greater than 0 and less than a total number of cylinders of the engine;

disabling fueling of the M cylinders while opening of the intake and exhaust valves of the M cylinders is deactivated; and

while fueling of the M cylinders is disabled and opening of the intake and exhaust valves of the M cylinders is deactivated, controlling fuel injection of other cylinders of the engine based on a predetermined rich air/fuel ratio that is fuel rich relative to the stoichiometric air/fuel ratio for the fuel;

re-activating opening of the intake and exhaust valves of the M cylinders in response to a determination that;

the amount of ammonia stored by SCR catalyst is greater than a second predetermined amount of ammonia, wherein the second predetermined amount of ammonia is greater than the first predetermined amount of ammonia; and

the engine load is increasing;

controlling fuel injection of the M cylinders after the re-activation based on the predetermined lean air/fuel ratio in response to the determination that;

the amount of ammonia stored by SCR catalyst is greater than the second predetermined amount of ammonia; and

the engine load is increasing;

continuing to deactivate the opening of the intake and exhaust valves of the M cylinders of the engine in response to a determination that;

the amount of ammonia stored by SCR catalyst is greater than the second predetermined amount of ammonia; and

the engine load is not increasing; and

during the continued deactivation, controlling the fuel injection of the other cylinders based on the predetermined lean air/fuel ratio in response to the determination that;

the amount of ammonia stored by SCR catalyst is greater than the second predetermined amount of ammonia; and

the engine load is not increasing.

4. The engine control method of claim 3 wherein M is equal to one-half of the total number of cylinders of the engine.