CN109209569B

CN109209569B - Diesel engine thermal management control strategy

Info

Publication number: CN109209569B
Application number: CN201710551561.4A
Authority: CN
Inventors: 王洪锋; 杜刚; A.古普塔
Original assignee: Cummins Inc
Current assignee: Cummins Inc
Priority date: 2017-07-07
Filing date: 2017-07-07
Publication date: 2022-01-25
Anticipated expiration: 2037-07-07
Also published as: CN109209569A

Abstract

A system and method for thermal management of an aftertreatment component is described. The disclosed systems and methods employ electronic wastegates, intake air throttle, and exhaust throttle in a prescribed manner to increase exhaust gas temperatures while minimizing fuel losses and operational inefficiencies.

Description

Diesel engine thermal management control strategy

Technical Field

The present disclosure relates generally to internal combustion engine operation, and more particularly to systems and methods for combustion and thermal management for diesel engine operation.

Background

Thermal management of the aftertreatment system and/or the intake air flow of the internal combustion engine may provide operational benefits (such as more efficient combustion processes and more efficient aftertreatment device operation). For example, high Turbine Outlet Temperatures (TOT) are required to achieve desired Selective Catalytic Reduction (SCR) conversion efficiencies and soot removal of other aftertreatment components, such as diesel oxidation catalysts and/or particulate filters.

Although turbochargers with Variable Geometry (VG) inlets have been used to increase exhaust gas temperature, VG turbochargers are more expensive than wastegate turbochargers. Exhaust gas heaters are also expensive and require a generator to generate energy to operate the heater. Other strategies, such as Exhaust Gas Recirculation (EGR), Hydrocarbon (HC) dosing, cylinder deactivation, and variable valve timing (VVA), have also been used for thermal management of aftertreatment systems. However, these strategies may introduce fuel loss, cost, and/or reliability issues. Therefore, there is a need for further improvement of this technology.

Disclosure of Invention

Systems and methods for controlling exhaust gas temperature and airflow through an internal combustion engine for thermal management of an aftertreatment system of a multi-cylinder diesel internal combustion engine are disclosed.

In some embodiments, the systems and/or methods are used with an internal combustion engine including a plurality of cylinders for producing exhaust gas for treatment by at least one aftertreatment device. The system includes at least one turbocharger, an Intake Air Throttle (IAT), an Exhaust Air Throttle (EAT), and a fueling system. The at least one aftertreatment device may include, for example, a catalyst and/or a particulate filter. The reciprocating engine may be a four-stroke diesel engine. The turbocharger may include an electronic controller wastegate (EWG) that bypasses the turbine. The fuel injector may be a common rail type fuel injector, although other fueling systems are also contemplated. Although the systems and methods described herein may be used without a variable geometry turbine and/or EGR system, the inclusion of a variable geometry turbine and/or EGR system is not excluded in all embodiments unless expressly claimed otherwise.

The systems and methods include selecting one or more operating modes in which one or more target conditions for exhaust gas/aftertreatment temperature may be achieved. The one or more modes of operation may include: positioning the EWG to regulate airflow through the internal combustion engine in response to the exhaust gas temperature being above a first threshold; in response to the exhaust gas temperature being below a first threshold and above a second threshold, locating at least one of the IAT and the EWG to achieve a desired temperature; and positioning at least one of the EAT and the IAT to achieve the desired temperature in response to the exhaust temperature being below the second threshold.

The one or more operating modes may include a first operating mode for providing the SCR catalyst at a desired temperature for operating efficiency. The one or more modes of operation may include a second mode of operation for providing soot removal or regeneration conditions for the oxidation catalyst and/or the particulate filter.

This summary is provided to introduce a selection of concepts that are further described below in the illustrative embodiments. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. Other embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.

Drawings

FIG. 1 illustrates one embodiment of an internal combustion engine system in which airflow through the internal combustion engine is managed in a prescribed manner to provide effective thermal management of the aftertreatment component at reduced cost and with minimal fuel loss.

FIG. 2 illustrates one embodiment of a cylinder of the internal combustion engine of FIG. 1.

FIG. 3 illustrates a flow diagram of one embodiment of a process for managing operation of the internal combustion engine system of FIG. 1.

FIG. 4 is a graphical representation of various temperature thresholds and levers associated with the temperature thresholds for managing the combustion heat output of the internal combustion engine system of FIG. 1.

FIG. 5 is an illustration of engine speed versus torque and expected exhaust temperature associated with the engine speed versus torque along with various thresholds selected by an actuator for managing combustion and heat output of an internal combustion engine in a first mode of operation.

FIG. 6 is an illustration of engine speed versus torque and expected exhaust temperature associated with the engine speed versus torque along with various thresholds selected by an actuator for managing combustion and heat output of an internal combustion engine in a second operating mode.

Fig. 7, in conjunction with the diagrams of fig. 3-6, shows a flow chart of another embodiment of a process for managing operation of the internal combustion engine system of fig. 1.

Detailed Description

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, any alterations and further modifications in the illustrated embodiments, and any further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

Referring to FIG. 1, a system 10 includes a four-stroke internal combustion engine 12. Fig. 1 shows an embodiment in which the engine 12 is a diesel engine, but other engine types are not excluded. The engine 12 may include a plurality of cylinders 14. FIG. 1 shows a plurality of cylinders 14 in an arrangement that includes, for illustrative purposes only, six cylinders in an in-line arrangement. Any number of cylinders and any arrangement of cylinders suitable for use in an internal combustion engine may be utilized. The number of cylinders 14 that can be used can vary from one cylinder to eighteen or more cylinders. Further, the following description will sometimes refer to one of the cylinders 14. It should be appreciated that corresponding features of the cylinder 14 described with reference to fig. 2 and elsewhere herein may exist for all or a subset of the other cylinders of the engine 12.

As shown in FIG. 2, the cylinder 14 houses a piston 16, the piston 16 being operatively attached to a crankshaft 18, the crankshaft 18 being rotated by the reciprocating motion of the piston 16 within the cylinder 14. Within the cylinder head 20 of the cylinder 14, there is at least one intake valve 22, at least one exhaust valve 24, and a fuel injector 26, the fuel injector 26 providing fuel to a combustion chamber 28, the combustion chamber 28 being formed by the cylinder 14 between the piston 16 and the cylinder head 20. In other embodiments, fuel may be provided to combustion chamber 28 by port injection or by injection in the intake system from upstream of combustion chamber 28.

The term "four-stroke" herein refers to the following four strokes-intake, compression, power, and exhaust-performed by piston 16 during two separate rotations of engine crankshaft 18. The stroke begins at Top Dead Center (TDC) when piston 16 is at the top of cylinder head 20 of cylinder 14, or at Bottom Dead Center (BDC) when piston 16 reaches its lowest point in cylinder 14.

During the intake stroke, piston 16 descends from cylinder head 20 of cylinder 14 to the bottom of the cylinder (not shown), thereby reducing the pressure in combustion chamber 28 of cylinder 14. Where the engine 12 is a diesel engine, air entering through the intake valves 22 forms a combustion charge in the combustion chamber 28 when the intake valves 22 are open.

Fuel from fuel injectors 26 is supplied by a high pressure common rail system 30 connected to a fuel tank 32. Fuel from a fuel tank 32 is drawn in by a fuel pump (not shown) and fed to the common rail fuel system 30. Fuel fed from a fuel pump accumulates in a common rail fuel system 30, and the accumulated fuel is supplied to the fuel injectors 26 of each cylinder 14 through fuel lines 34. The fuel accumulated in the common rail system may be pressurized to increase and control the fuel pressure of the fuel delivered to the combustion chamber 28 of each cylinder 14.

During the compression stroke, both the intake and

exhaust valves

22, 24 are closed, the piston 16 is returning toward TDC, and fuel is injected into the compressed air near TDC in a main injection event, and the compressed fuel-air mixture is ignited in the combustion chamber 28 after a brief delay. Where the engine 12 is a diesel engine, this results in the combustion charge being ignited. The ignition of the air and fuel causes a rapid increase in the pressure in combustion chamber 28 that is applied to piston 16 during the power stroke of piston 16 toward BDC. Combustion phasing in combustion chamber 28 is calibrated such that an increase in pressure in combustion chamber 28 pushes piston 16, providing a net positive effect in the force/work/power of piston 16.

During the exhaust stroke, the piston 16 returns toward TDC as the exhaust valve 24 opens. This action discharges combustion products resulting from the combustion of fuel in combustion chamber 28 through exhaust valve 24 and expels the spent fuel-air mixture (exhaust gas). Post-combustion fuel injection allows fuel not to participate in the combustion process and may provide hydrocarbons in the exhaust stream that are used to increase exhaust gas temperatures under certain operating conditions, as will be discussed further below.

Referring again to FIG. 1, intake air flows through an intake passage 36 and an intake manifold 38 before reaching the intake valves 22. The intake passage 36 may be connected to a compressor 40a of a turbocharger 40 and an intake air throttle valve (IAT) 42. The intake air may be cleaned by an air cleaner (not shown), compressed by compressor 40a, cooled by charge air cooler 44, and then drawn into combustion chambers 28 through intake air throttle valve 42. Intake air throttle valve 42 may be controlled to affect airflow into cylinders 14 and to increase or decrease exhaust gas temperature by increasing or decreasing combustion temperature in cylinder chamber 28.

A Charge Air Cooler (CAC) 44 is disposed downstream of the compressor 40 a. In one example, the compressor 40a may increase the temperature and pressure of the intake air, while the CAC 44 may increase the charge density and provide more air to the cylinders. In another example, the CAC 44 may be a Low Temperature Aftercooler (LTA). The CAC 44 uses air as the cooling medium, while the LTA uses coolant as the cooling medium.

Exhaust gas flows from the combustion chamber 28 into the exhaust passage 46 through the

exhaust manifold portions

48a and 48 b. Exhaust passage 46 is connected to turbine 40b and an electronically controlled wastegate (EWG) 50 of turbocharger 40, and subsequently to an aftertreatment system 52. The exhaust gas discharged from the combustion chamber 28 drives the turbine 40b to rotate. The EWG 50 is a device that enables a portion of the exhaust gas to bypass the turbine 40b through a passage 54. Thus, less exhaust energy is available to the turbine 40b, resulting in less power being transferred to the compressor 40 a. Generally, this results in a reduced rise in inlet air pressure across the compressor 40a and a reduced/reduced inlet air density/flow. The EWG 50 may include an actuator connected to a control valve, which may be of the open/close type, or a full authority valve that allows control of the amount of bypass flow or any substance therebetween. The exhaust passage 46 also includes an exhaust throttle valve 58, the exhaust throttle valve 58 for regulating the flow of exhaust gas through the exhaust passage 46. The exhaust gas, which may be a combination of bypass and turbine flow, then enters the aftertreatment system 52.

The aftertreatment system 52 may include one or more devices for treating and/or removing substances from the exhaust gas that may be harmful components, including carbon monoxide, nitrogen dioxide, hydrocarbons, and/or soot in the exhaust gas. In some examples, aftertreatment system 52 may include at least one of a catalytic device and a particulate matter filter. The catalytic devices may be a Diesel Oxidation Catalyst (DOC) device 52a, an ammonia oxidation (AMOX) catalyst device 52b, and/or a Selective Catalytic Reduction (SCR) device 52 c. The reduction catalyst may include any suitable reduction catalyst, for example, SCR catalyst 52 c. The particulate matter filter may be a Diesel Particulate Filter (DPF) 52d or a partial flow particulate filter (PFF) that traps particulate matter in a portion of the flow; in contrast, the entire amount of exhaust gas passes through the particulate filter 52 shown in FIG. 1.

The arrangement of components in aftertreatment system 52 may be any arrangement suitable for engine 12. For example, in one embodiment, the DOC 52a and DPF 52d are disposed upstream of the SCR catalyst 52 c. In one example, a reductant delivery device is disposed between the DPF 52d and the SCR catalyst 52c for injecting reductant into the exhaust gas upstream of the SCR catalyst 52 c. The reductant may be urea, diesel exhaust fluid, or any suitable reductant that is injected in liquid and/or gaseous form.

The controller 80 is configured to receive data from the various sensors as inputs and to send command signals as outputs to the various actuators. Some of the various sensors and actuators that may be used will be described in detail below. The controller 80 may include, for example, a processor, memory, clock, and input/output (I/O) interfaces.

System 10 includes various sensors, such as an intake manifold pressure/temperature sensor 70, an exhaust manifold pressure/temperature sensor 72, one or more aftertreatment sensors 74 (such as differential pressure sensors, temperature sensors, pressure sensors, composition sensors), an engine sensor 76 (which may detect an air/fuel ratio of an air/fuel mixture supplied to the combustion chamber, crank angle, rotational speed of the crankshaft, etc.), a turbine outlet temperature sensor 77, and a fuel sensor 78 (which may detect fuel pressure and/or other properties of the fuel, common rail 38, and/or fuel injectors 26). Any other sensors known in the art for use in engine systems are also contemplated.

The system 10 may further include various actuators for: opening and closing the intake valve 22; opening and closing the exhaust valve 24; injecting fuel from the fuel injector 26; open and close the EWG 50; IAT 42; and/or EAT 58. The actuator is not shown in fig. 1, but one skilled in the art will know how to implement the mechanisms required for each component to perform the intended function.

During operation, the controller 80 may receive information from the various sensors listed above through the I/O interface, use the processor to process the received information based on algorithms stored in the memory, and then send command signals to the various actuators through the I/O interface. For example, the controller 80 may receive information regarding the temperature input, process the temperature input, and then send one or more command signals to one or more actuators of the EWG 50, IAT 42, and EAT 58 to increase the temperature of the exhaust gas based on the temperature input and the control strategy to achieve target conditions for combustion and thermal management of the system 10, such as shown in FIGS. 3-6.

Referring to FIG. 3, a process 100 for controlling the temperature of exhaust gas output from the engine 12 to achieve desired thermal management conditions is shown. Specifically, the sequence of operation of the actuators for the three levers, including EWG 50, IAT 42, and EAT 58, are controlled in coordination with one another to reduce airflow through the engine 12 and increase the temperature of the exhaust gas output from the engine 12 to achieve target conditions for one or more components of the aftertreatment system 52. Depending on the operating mode, the target conditions may include a desired or effective operating temperature of one or more components of the aftertreatment system 52, or the target conditions may include a soot removal or regeneration temperature of one or more components of the aftertreatment system 52.

The process 100 begins at 102 with a key-on event, an engine start event, and/or other start events occurring periodically, in response to a condition indicating that a thermal management condition may exist, such as after the engine 12 is operating for a certain period of time (after the last thermal management event or after the engine 12 consumes a certain amount of fuel). Process 100 continues at conditional 104 to determine whether thermal management conditions are met. Thermal management conditions may include, for example: determining that a temperature associated with the SCR catalyst 52c is within a range or above a predetermined threshold; or to determine that soot removal or regeneration temperatures of the DOC 52a and/or DPF 52d are required. The temperature of the SCR catalyst 52c or other aftertreatment component may be determined by, for example, determining the TOT, the inlet temperature, the outlet temperature, the mid-bed temperature, and/or an average of one or more temperatures of one or more components of the aftertreatment system 52, the turbine 40a, the exhaust gas, or other suitable indicators.

If conditional 104 is affirmative, process 100 ends at 122. If conditional 104 is negative, the process 100 continues at operation 106 to determine the position of the EWG 50 that alters the airflow through the engine 12 and turbine 40a to achieve the desired airflow and maintain or improve thermal management conditions. Because there is a limit to the positioning of the EWG 50 to maintain a minimum desired exhaust flow through the turbine 40a, the amount of temperature change that can be achieved by controlling the EWG position may not be sufficient to achieve the desired exhaust temperature. However, the manipulation of the EWG 50 is preferred because the EWG position can be used to obtain some temperature rise while obtaining fuel efficiency benefits by improving cycle efficiency (particularly at high speeds and part loads).

From operation 106, process 100 proceeds to conditional statement 108 to determine whether thermal management conditions are met. If conditional statement 108 is affirmative, then process 100 ends at 122. If conditional 108 is negative, process 100 continues at operation 110 to determine the position of the IAT 42, which, alone or in combination with the position of the EWG 50, varies the airflow through the engine 12 and, therefore, the exhaust temperature output from the engine 12 to achieve the desired exhaust temperature for the thermal management condition.

From operation 110, process 100 proceeds to conditional sentence 112 to determine whether the thermal management condition is satisfied. If conditional 112 is affirmative, process 100 ends at 122. If conditional 112 is negative, process 100 continues at operation 114 to determine a position of at least one of EAT 58 and IAT 42 that further alters the airflow through engine 12 and the exhaust gas temperature output from engine 12 to achieve the desired temperature for the thermal management condition. However, in certain embodiments, the location of the EWG 50 will not be used to further restrict exhaust flow to avoid excessively reducing turbine speed and creating a risk of oil leakage.

From operation 114, process 100 proceeds to conditional statement 116 to determine whether thermal management conditions are met. If conditional statement 116 is affirmative, then process 100 ends at 122. If conditional 116 is negative, process 100 continues at operation 118 to determine a post-combustion fuel injection strategy that further changes the exhaust gas temperature to achieve the desired temperature for the thermal management condition. For example, post-combustion fuel injection may be used to increase the inlet temperature of the DOC 52a to reach the light-off temperature.

From operation 118, process 100 proceeds to conditional sentence 120 to determine whether thermal management conditions are met. If conditional statement 120 is affirmative, then process 100 ends at 122. If conditional 120 is negative, process 100 may return to operation 106 to further adjust or maintain the position of the EWG 50 to change the temperature of the exhaust gas output from the engine 12 to achieve the desired airflow and maintain the temperature of the thermal management condition. The remaining steps of process 100 will continue as described above.

With respect to operation 118, the controller 80 may be configured to enable post-combustion fuel injection using the fuel system 30. In one embodiment, the disclosed method and/or controller configuration includes selecting one or more operating modes in which one or more target conditions of the exhaust gas, such as a target aftertreatment temperature for the SCR catalyst 52c or a target soot removal or regeneration temperature for the DOC 52a and/or DPF 52d, may be achieved. The one or more operating modes may include providing one or more post-combustion fuel injections to provide hydrocarbons in the exhaust flow that react with the one or more aftertreatment components to increase exhaust gas temperature. Extremely late post-fuel injection occurs after combustion of the normal or main injection event is complete and is smaller in amount than the main injection because there is less oxygen in the cylinder. The main injection event occurs during the expansion/combustion stroke, while the late injection described herein occurs during the exhaust stroke.

The normal or main fuel injection event may be selected, for example, based on a set of engine parameter operating maps as a function of engine speed and torque demand, main injection time and quantity, and rail pressure, and may be calibrated as a function of engine speed and load. The extremely late post injection is an amount of fuel other than the main fuel injection (which may include multiple injections) and is provided for combustion and thermal management, rather than for meeting engine load conditions.

Referring to FIG. 4, various operating conditions and temperature thresholds associated therewith are illustrated for another embodiment of a thermal management strategy for aftertreatment system 52. In response to the aftertreatment system temperature being above the threshold temperature a, no thermal management is required or performed. In response to the aftertreatment system temperature being below threshold temperature a and above threshold temperature B, the IAT 42 alone or the IAT 42 in conjunction with the EWG 50 are controlled to increase the exhaust gas temperature. In response to the aftertreatment system temperature being below threshold temperature B, the EAT 58 is controlled in conjunction with positioning of the IAT 42 to increase the exhaust gas temperature.

Further, in response to the aftertreatment temperature being above the threshold temperature C associated with efficient operation of, for example, the SCR catalyst 52C, the fueling strategy A1 is selected to allow for higher NOx output from the engine 12. In response to the aftertreatment temperature being below the threshold temperature C, the fueling strategy A0 is selected to provide a lower NOx output from the engine 12 when the aftertreatment system 52 is not already at the desired operating temperature.

In certain embodiments, threshold temperature a is 270 degrees celsius and threshold temperature B is 230 degrees celsius. The threshold temperature C is 250 degrees celsius. Other threshold temperatures are also contemplated depending on the application and the specific characteristics of the aftertreatment component and/or the operating conditions.

FIG. 5 illustrates engine speed versus torque and turbine outlet expected operating temperatures T1-T17 for various speed/torque conditions. The map also includes various thermal management control boundaries for one embodiment for controlling the temperature of the SCR catalyst 52 c. For example, above the solid line boundary, thermal management is not required. Between the line 1 boundary and the solid line boundary, the EWG 50 can be used and/or activated to control airflow through the engine for protection of the turbine, but thermal management is not required. Between lines 1 and 2, the IAT 42 can be separately controlled and/or enabled for thermal management. Between

lines

2 and 3, the IAT 42 and EAT 58 can be controlled and/or enabled for thermal management. Below line 3, EAT 58 and post-combustion fuel injection are enabled for thermal management.

FIG. 6 also shows engine speed versus torque and turbine outlet expected operating temperatures T1-T17. The map also includes various thermal management control boundaries for one embodiment for controlling the regeneration temperature of the DOC 52a and/or DPF 52 d. Above the solid boundary line, no thermal management is required. Between line 1 and the solid boundary line, the EWG 50 is enabled and/or used for thermal management and protection of the turbine. Between

lines

4 and 5, the IAT 42 and EWG 50 are enabled and/or controlled for thermal management. Between

lines

5 and 6, the IAT 42 and EAT 58 are enabled and/or controlled for thermal management. Below line 6, EAT 58 and post-combustion fuel injection are enabled and/or used for thermal management.

Referring to fig. 7, another embodiment process 200 is shown to achieve desired thermal management conditions. Specifically, the sequence of operation of the actuators for the two levers, including the IAT 42 and the EAT 58, are controlled in coordination with one another to reduce airflow through the engine 12 and increase the temperature of the exhaust gas output from the engine 12 to achieve target conditions for one or more components of the aftertreatment system 52. Depending on the operating mode, the target conditions may include a desired or effective operating temperature of one or more components of the aftertreatment system 52, or the target conditions may include a soot removal or regeneration temperature of one or more components of the aftertreatment system 52.

The process 200 begins at 202 with a key-on event, an engine start event, and/or other start events occurring periodically, in response to a condition indicating that a thermal management condition may exist, such as after the engine 12 is operating for a certain period of time (after the last thermal management event or after the engine 12 consumes a certain amount of fuel). Process 200 continues at conditional 204 to determine whether the temperature (or other representative temperature) of one or more components of aftertreatment system 52 is above temperature threshold a. The temperature may be determined by, for example, determining an average of the TOT, the inlet temperature, the outlet temperature, the middle bed temperature, and/or one or more temperatures of one or more components of the aftertreatment system 52, the turbine 40a, the exhaust gas, or other suitable indicators.

If conditional statement 204 is affirmative, then process 200 ends at 224. If conditional 204 is negative, process 200 continues at conditional 206 to determine if the temperature is greater than threshold B. If conditional 206 is affirmative, then process 200 continues at conditional 208 to determine if the engine load and airflow conditions are above line 1 or line 4 of FIG. 5 or FIG. 6 (depending on the operating mode). If above line 1 or line 4, then process 200 continues at operation 210 without thermal management, as the load and airflow conditions should increase the temperature. If the load and airflow conditions are below line 1 or line 4 of FIG. 5 or FIG. 6, then the process 200 continues at operation 212 with thermal management by positioning only the IAT 42 to help increase the exhaust gas temperature for thermal management.

If conditional statement 206 is negative, then process 200 continues at conditional statement 214 to check the load and airflow conditions of internal combustion engine 12. If the load and airflow conditions at conditional 214 are above line 1 or line 4 of fig. 5 or fig. 6 (depending on the mode of operation), then thermal management is not performed at operation 216 because only the load and airflow conditions should increase the temperature. If the load and airflow conditions are between lines 1 and 2 of FIG. 5 or between

lines

4 and 5 of FIG. 6, then the process 200 continues at operation 218 to provide thermal management to increase the exhaust temperature by the positioning of the IAT 42 only. If the load and airflow conditions are below line 2 of FIG. 5 or below line 5 of FIG. 6, then the process 200 continues at operation 220 to provide thermal management to increase the exhaust temperature by the positioning of the EAT 58 in conjunction with the positioning of the IAT 42.

Process 200 continues at conditional 222 to determine whether the temperature meets thermal management requirements. If conditional 222 is affirmative, process 200 ends at 224. If conditional 222 is negative, process 200 returns to conditional 204 and repeats.

The control process implemented by the controller 80 may be performed by a processor of the controller 80 executing program instructions (algorithms) stored in a memory of the controller 80. The description herein may be implemented with system 10. In certain embodiments, the system 10 further includes a controller 80, the controller 80 being constructed or configured to perform certain operations to control the system 10 to achieve one or more target conditions. In certain embodiments, the controller forms part of a processing subsystem that includes one or more computing devices having memory, processing, and communication hardware. The controller may be a single device or a distributed device, and the functions of the controller 80 may be performed by hardware and/or by instructions encoded on a computer-readable medium.

In certain embodiments, the controller 80 includes one or more modules configured to functionally execute the operations of the controller. The description herein including modules emphasizes the structural independence of the aspects of the controller and illustrates one grouping of operations and responsibilities of the controller. It is understood that other groupings performing similar overall operations are also within the scope of the present patent application. Modules may be implemented in hardware and/or software on a non-transitory computer-readable storage medium, and modules may be distributed across various hardware or other computer components.

Certain operations described herein include operations for interpreting or determining one or more parameters. As utilized herein, interpreting or determining includes receiving a value by any method known in the art, including at least receiving a value from a data link or network communication, receiving an electronic signal (e.g., a voltage, frequency, current, or PWM signal) indicative of the value, receiving a software parameter indicative of the value, reading the value from a memory location on a non-transitory computer readable storage medium, receiving the value as a runtime parameter by any means known in the art, and/or by receiving a default value that can be used to calculate a value for the interpreted or determined parameter and/or by referencing a value to be interpreted or determined as a parameter value.

In one embodiment, the controller 80 is configured for connection to a plurality of

sensors

70, 72, 74, 76, 77, 78 and is operable to interpret signals from the plurality of

sensors

70, 72, 74, 76, 77, 78 associated with operation of the engine 12. The controller 80 is configured to: in response to a thermal management condition of at least one of the

aftertreatment devices

52a, 52b, 52c, 52d, a first command is provided to adjust a position of the EWG 50 to vary airflow through the internal combustion engine 12.

The controller 80 is further configured to: in response to adjusting the position of EWG 50 failing to satisfy the thermal management condition of at least one

aftertreatment device

52a, 52b, 52c, 52d, a second command is provided to adjust the position of the IAT 42 throttle valve to increase the temperature of the exhaust gas produced by internal combustion engine 12 passing through at least one

aftertreatment device

52a, 52b, 52c, 52 d.

The controller 80 is further configured to: in response to adjusting the position of the IAT 42 failing to satisfy the thermal management condition of the at least one

aftertreatment device

52a, 52b, 52c, 52d, a third command is provided to adjust the position of the EAT 58 to further increase the temperature of the exhaust gas passing through the at least one

aftertreatment device

52a, 52b, 52c, 52 d. In another embodiment, the controller 80 is configured to: in response to adjusting the position of EAT 58 failing to satisfy the thermal management condition, a fourth command is provided to inject an amount of post-combustion fuel into at least one cylinder 14 of internal combustion engine 12 such that the amount of fuel is received by at least one

aftertreatment device

52a, 52b, 52c, 52 d.

In another embodiment, the controller 80 is configured to determine a temperature associated with at least one

aftertreatment device

52a, 52b, 52c, 52 d. In response to the temperature being above the first threshold, the controller 80 is operable to command the actuator to adjust the position of the EWG 50 to vary the airflow through the internal combustion engine 12. In response to the temperature being below the first threshold and above the second threshold, the controller 80 may be operable to command the actuator to adjust the position of the IAT 42 alone or to adjust the position of the IAT 42 in conjunction with the EWG 50 to reduce airflow through the engine 12 and increase the temperature of the exhaust gases. In response to the temperature being below the second threshold, the controller 80 is operable to command the actuator to adjust at least the position of the EAT 58 and in some embodiments also the position of the IAT 42 to reduce airflow through the engine 12 and increase the temperature of the exhaust gas. In response to the temperature being less than the third threshold (less than the second threshold), controller 80 is operable to provide a command to fueling system 30 to inject an amount of post-combusted fuel into at least one cylinder 14 of internal combustion engine 12 such that the amount of fuel is received by at least one

aftertreatment device

52a, 52b, 52c, 52 d.

Various aspects of the present disclosure are contemplated. According to one aspect, a method includes operating an internal combustion engine system including an internal combustion engine having a plurality of cylinders that receive a flow from an intake system including an intake air throttle valve. The internal combustion engine system includes a turbocharger and an exhaust throttle valve in an exhaust system. The turbocharger includes a turbine having a controllable wastegate, and the exhaust system receives exhaust gas generated by the internal combustion engine through combustion of fuel provided from a fueling system to at least a portion of the plurality of cylinders. The internal combustion engine system further comprises at least one after-treatment device in the exhaust system, through which the exhaust gas passes. The method further comprises the following steps: adjusting a position of the wastegate to increase a temperature of the exhaust gas passing through the at least one aftertreatment device in response to a thermal management condition of the at least one aftertreatment device; in response to adjusting the position of the wastegate failing to satisfy the thermal management condition of the at least one aftertreatment device, adjusting a position of the intake air throttle to further increase the temperature of the exhaust gas passing through the at least one aftertreatment device; and in response to adjusting the position of the intake air throttle failing to satisfy the thermal management condition of the at least one aftertreatment device, adjusting a position of the exhaust throttle in the exhaust system to further increase the temperature of the exhaust gas passing through the at least one aftertreatment device.

In one embodiment, in response to adjusting the position of the exhaust throttle valve failing to satisfy the thermal management condition of the at least one aftertreatment device, the method includes injecting an amount of post-combustion fuel into the portion of the plurality of cylinders to further increase the temperature of the exhaust gas passing through the at least one aftertreatment device. In another embodiment, the thermal management condition comprises a temperature condition of the SCR catalyst being below an effective operating temperature threshold.

In another embodiment, the thermal management condition comprises a TOT and comprises: a first TOT threshold above which said position of said wastegate is adjusted; a second TOT threshold below which the position of the exhaust throttle valve is adjusted and the intake air throttle valve is adjusted, and when a turbine outlet temperature is between the first and second TOT thresholds, only the position of the intake air throttle valve is adjusted.

In another embodiment, the thermal management condition comprises a temperature condition of the at least one aftertreatment device being below a regeneration temperature threshold. In another embodiment, the intake system includes a compressor, and the intake air throttle is located downstream of the compressor and the exhaust throttle is located downstream of the compressor. In a refinement of this embodiment, the intake system includes a charge air cooler located between the compressor and the intake air throttle.

According to another aspect, a method for thermally managing an aftertreatment system includes: determining a temperature associated with an aftertreatment device in the aftertreatment system, the aftertreatment device receiving exhaust gas produced by an internal combustion engine; adjusting a position of a wastegate of a turbine upstream of the aftertreatment device to vary airflow through the internal combustion engine in response to the temperature being above a first threshold; in response to the temperature being below the first threshold and above a second threshold, adjusting a position of an intake air throttle valve located upstream of the internal combustion engine to increase the temperature of the exhaust gas; and adjusting a position of an exhaust throttle valve downstream of the wastegate to increase the temperature of the exhaust gas in response to the temperature being below the second threshold.

In one embodiment, adjusting the position of the exhaust throttle valve includes adjusting the positions of the exhaust throttle valve and the intake air throttle valve together to increase the temperature of the exhaust gas. In another embodiment, in response to the temperature being less than a third threshold that is less than the second threshold, the method includes injecting an amount of post-combustion fuel into at least one cylinder of the internal combustion engine such that the amount of fuel is received by the aftertreatment system as the exhaust gas. In a refinement of this embodiment, the aftertreatment device is an oxidation catalyst.

In another embodiment, adjusting the position of the intake air throttle and the exhaust throttle reduces the airflow through the engine to increase the temperature of the exhaust gas. In another embodiment, the aftertreatment device is a selective catalytic reduction catalyst. In another embodiment, determining the temperature associated with the aftertreatment device includes determining at least one of a turbine outlet temperature, an inlet temperature of the aftertreatment device, an outlet temperature of the aftertreatment device, and a mid-bed temperature of the aftertreatment device.

According to another aspect, a system comprises: an internal combustion engine comprising a plurality of cylinders that receive a flow of material from an air intake system; an exhaust system for receiving exhaust gas produced by combusting a fuel provided from a charging system to at least a portion of the plurality of cylinders; and at least one aftertreatment device in the exhaust system. The system also includes a turbine in the exhaust system, the turbine including an electronically controllable wastegate. The system also includes an exhaust throttle valve in the exhaust system downstream of the wastegate and an intake air throttle valve in the intake system. A plurality of sensors are operable to provide signals indicative of operating conditions of the system, and a controller is connected to the plurality of sensors and the wastegate, the intake air throttle, and the exhaust throttle. The controller is operable to interpret the signals from the plurality of sensors, wherein the controller is configured to determine a temperature associated with the at least one aftertreatment device. The controller is further configured to: adjusting a position of the wastegate to vary airflow through the internal combustion engine in response to the temperature being above a first threshold; and in response to said temperature being below said first threshold and above a second threshold, adjusting a position of said intake air throttle to increase said temperature of said exhaust gas; and adjusting a position of the exhaust throttle valve to increase the temperature of the exhaust gas in response to the temperature being below the second threshold.

In one embodiment, the controller is configured to: in response to the temperature being below the second threshold, adjusting the position of the exhaust throttle valve and adjusting the position of the intake air throttle valve together to increase the temperature of the exhaust gas. In another embodiment, in response to the temperature being less than a third threshold that is less than the second threshold, the controller is configured to inject an amount of post-combustion fuel from the charging system into at least one cylinder of the internal combustion engine such that the amount of fuel is received by the at least one aftertreatment device.

According to another aspect, an apparatus includes a controller configured for connection to a plurality of sensors and operable to interpret the signals from the plurality of sensors in association with operation of an internal combustion engine. The controller is configured to: providing a first command to adjust a position of a wastegate to vary airflow through the internal combustion engine in response to a thermal management condition of at least one aftertreatment device coupled to the internal combustion engine; and in response to adjusting the position of the wastegate failing to satisfy the thermal management condition of the at least one aftertreatment device, providing a second command to adjust a position of an intake air throttle to increase a temperature of exhaust gas produced by the internal combustion engine passing through the at least one aftertreatment device; and in response to adjusting the position of the intake air throttle failing to satisfy the thermal management condition of the at least one aftertreatment device, providing a third command to adjust a position of an exhaust throttle to further increase the temperature of the exhaust gas passing through the at least one aftertreatment device.

In one embodiment, the thermal management condition comprises the SCR catalyst being below a threshold temperature. In another embodiment, the second command alone adjusts the position of the intake air throttle valve, and the third command adjusts the position of the intake air throttle valve along with the position of the exhaust throttle valve. In another embodiment, in response to adjusting the position of the exhaust throttle valve failing to satisfy the thermal management condition, the controller is configured to provide a fourth command to inject an amount of post-combustion fuel into at least one cylinder of the internal combustion engine such that the amount of fuel is received by the at least one aftertreatment device.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only certain exemplary embodiments have been shown and described. Those skilled in the art will appreciate that many modifications may be made to the exemplary embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.

In reading the claims, it is intended that when words such as "a," "an," "at least one," or "at least a portion" are used, there is no intention to limit the claims to only one item unless specifically stated to the contrary in the claims. When the language "at least a portion" and/or "a portion" is used, the item can include a portion and/or the entire item unless specifically stated to the contrary.

Claims

1. A method for thermally managing an aftertreatment system of an internal combustion engine, comprising:

operating an internal combustion engine system, the internal combustion engine system comprising an internal combustion engine having a plurality of cylinders that receive a flow from an intake system including an intake air throttle valve, the internal combustion engine system comprising a turbocharger and an exhaust throttle valve in an exhaust system, the turbocharger comprising a turbine with a controllable wastegate, the exhaust system for receiving exhaust gas produced by combustion of fuel by the internal combustion engine, the fuel being provided to at least a portion of the plurality of cylinders from a fueling system, the internal combustion engine system further comprising at least one aftertreatment device in the exhaust system through which the exhaust gas passes;

adjusting a position of the wastegate to vary airflow through the internal combustion engine in response to thermal management conditions of the at least one aftertreatment device;

in response to adjusting the position of the wastegate failing to satisfy the thermal management condition of the at least one aftertreatment device, adjusting a position of the intake air throttle to increase a temperature of the exhaust gas passing through the at least one aftertreatment device; and

in response to adjusting the position of the intake air throttle failing to satisfy the thermal management condition of the at least one aftertreatment device, adjusting a position of the exhaust throttle in the exhaust system to further increase the temperature of the exhaust gas passing through the at least one aftertreatment device.

2. The method of claim 1, injecting an amount of post-combustion fuel into the portion of the plurality of cylinders to further increase the temperature of the exhaust gas passing through the at least one aftertreatment device in response to adjusting the position of the exhaust throttle failing to satisfy the thermal management condition of the at least one aftertreatment device.

3. The method of claim 1, wherein the thermal management condition comprises a temperature condition of a Selective Catalytic Reduction (SCR) catalyst being below an effective operating temperature threshold.

4. The method of claim 1, wherein the thermal management condition comprises a turbine outlet temperature, and comprising: a first turbine outlet temperature threshold above which the position of the wastegate is adjusted; a second turbine outlet temperature threshold below which the position of the exhaust throttle valve is adjusted and the intake air throttle valve is adjusted, and the position of the intake air throttle valve is adjusted solely when turbine outlet temperature is between the first turbine outlet temperature threshold and the second turbine outlet temperature threshold.

5. The method of claim 1, wherein the thermal management condition comprises a temperature condition of the at least one aftertreatment device being below a regeneration temperature threshold.

6. The method of claim 1, wherein the intake system includes a compressor, and the intake air throttle is located downstream of the compressor and the exhaust throttle is located downstream of the compressor.

7. The method of claim 6, wherein the intake system includes a charge air cooler located between the compressor and the intake air throttle.

8. A method for thermally managing an aftertreatment system, comprising:

determining a temperature associated with an aftertreatment device in the aftertreatment system, the aftertreatment device receiving exhaust gas produced by an internal combustion engine;

adjusting a position of a wastegate of a turbine upstream of the aftertreatment device to vary airflow through the internal combustion engine in response to the temperature being above a first threshold;

in response to the temperature being below the first threshold and above a second threshold, adjusting a position of an intake air throttle valve located upstream of the internal combustion engine to increase a temperature of the exhaust gas; and

adjusting a position of an exhaust throttle valve downstream of the wastegate to increase the temperature of the exhaust gas in response to the temperature being below the second threshold.

9. The method of claim 8, wherein adjusting the position of the exhaust throttle valve includes adjusting the positions of the exhaust throttle valve and the intake air throttle valve together to increase the temperature of the exhaust gas, and adjusting the intake air throttle valve alone in response to the temperature being below the first threshold and above the second threshold.

10. The method of claim 8, wherein in response to the temperature being less than a third threshold that is less than the second threshold, an amount of post-combustion fuel is injected into at least one cylinder of the internal combustion engine such that the amount of fuel is received by the aftertreatment system in the exhaust gas.

11. The method of claim 10, wherein the aftertreatment device is an oxidation catalyst.

12. The method of claim 8, wherein adjusting the position of the intake air throttle and the exhaust throttle reduces the airflow through the internal combustion engine to increase the temperature of the exhaust gas.

13. The method of claim 8, wherein the aftertreatment device is a selective catalytic reduction catalyst.

14. The method of claim 8, wherein determining the temperature associated with the aftertreatment device comprises determining at least one of a turbine outlet temperature, an inlet temperature of the aftertreatment device, an outlet temperature of the aftertreatment device, and a mid-bed temperature of the aftertreatment device.

15. A system for thermally managing an aftertreatment system of an internal combustion engine, comprising:

an internal combustion engine comprising a plurality of cylinders that receive a flow of material from an air intake system; an exhaust system for receiving exhaust gas produced by combusting fuel provided from a fueling system to at least a portion of the plurality of cylinders; and at least one aftertreatment device in the exhaust system;

a turbine in the exhaust system, the turbine comprising an electronically controllable wastegate;

an exhaust throttle valve in the exhaust system downstream of the wastegate;

an intake air throttle in the intake system;

a plurality of sensors operable to provide signals indicative of operating conditions of the system;

a controller connected to the wastegate, the intake air throttle, and the exhaust throttle, the controller further connected to the plurality of sensors and operable to interpret the signals from the plurality of sensors, wherein the controller is configured to determine a temperature associated with the at least one aftertreatment device, and wherein the controller is further configured to:

adjusting a position of the wastegate to vary airflow through the internal combustion engine in response to the temperature being above a first threshold;

in response to the temperature being below the first threshold and above a second threshold, adjusting a position of the intake air throttle to increase the temperature of the exhaust gas; and

adjusting a position of the exhaust throttle valve to increase the temperature of the exhaust gas in response to the temperature being below the second threshold.

16. The system of claim 15, wherein the controller is configured to: in response to the temperature being below the second threshold, adjusting the position of the exhaust throttle valve and adjusting the position of the intake air throttle valve to increase the temperature of the exhaust gas.

17. The system of claim 15, wherein in response to the temperature being less than a third threshold that is less than the second threshold, the controller is configured to inject an amount of post-combustion fuel from the fueling system into at least one cylinder of the internal combustion engine such that the amount of fuel is received by the at least one aftertreatment device.

18. An apparatus for thermally managing an aftertreatment system of an internal combustion engine, comprising:

a controller configured for connection to a plurality of sensors and operable to interpret signals from the plurality of sensors associated with operation of an internal combustion engine, wherein the controller is configured to: providing a first command to adjust a position of a wastegate to vary airflow through the internal combustion engine in response to a thermal management condition of at least one aftertreatment device coupled to the internal combustion engine; and in response to adjusting the position of the wastegate failing to satisfy the thermal management condition of the at least one aftertreatment device, providing a second command to adjust a position of an intake air throttle to increase a temperature of exhaust gas produced by the internal combustion engine passing through the at least one aftertreatment device; and in response to adjusting the position of the intake air throttle failing to satisfy the thermal management condition of the at least one aftertreatment device, providing a third command to adjust a position of an exhaust throttle to further increase the temperature of the exhaust gas passing through the at least one aftertreatment device.

19. The apparatus of claim 18 wherein the second command alone adjusts the position of the intake air throttle valve and the third command also adjusts the position of the intake air throttle valve along with the position of the exhaust throttle valve.

20. The apparatus of claim 18, wherein in response to adjusting the position of the exhaust throttle failing to satisfy the thermal management condition, the controller is configured to provide a fourth command to inject an amount of post-combusted fuel into at least one cylinder of the internal combustion engine such that the amount of fuel is received by the at least one aftertreatment device.