System and method for controlling operation of a hybrid vehicle

Abstract

A hybrid vehicle includes an engine, an energy storage device, and an aftertreatment system, the aftertreatment system including an SCR catalyst configured to treat a component of the exhaust gas. A controller is operably coupled to the engine, the energy storage device, and the aftertreatment system, and is configured to estimate an exhaust gas temperature and an exhaust gas flow rate based on a set of engine operating parameters. The controller determines an exhaust gas cooling rate based on the exhaust gas temperature, the flow rate, and the SCR catalyst temperature, and determines an ambient cooling rate based on the ambient temperature, the vehicle speed, and the catalyst temperature. The controller determines a rate of change of the SCR catalyst temperature based on the exhaust gas and the ambient cooling rate, and adjusts a load distribution between the engine and the energy storage device based on the rate of change of the SCR catalyst temperature.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 927,406, filed October 29, 2019, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present disclosure generally relates to hybrid vehicles, including aftertreatment systems and methods of controlling the temperature of such aftertreatment systems.

[0004] background

[0005] A hybrid vehicle includes an internal combustion engine and an energy storage device, such as a battery, and distributes the load between the engine and the battery to optimize fuel economy. A hybrid vehicle also includes an exhaust aftertreatment system that receives and treats the exhaust generated by the internal combustion engine. Typically, the exhaust aftertreatment system includes any of several different components to reduce the level of harmful exhaust emissions present in the exhaust. For example, certain exhaust aftertreatment systems include a selective catalytic reduction (SCR) catalyst for breaking down components of the exhaust, such as nitrogen oxides (NOx), included in the exhaust. x ) gas. The catalytic conversion efficiency of the SCR catalyst depends on the temperature of the SCR catalyst. When the engine load is low, the SCR catalyst will cool down, resulting in a decrease in the catalytic conversion efficiency of the SCR catalyst.

[0006] Overview

[0007] The embodiments described herein generally relate to systems and methods for controlling the temperature of an aftertreatment system included in a hybrid vehicle, and more particularly to systems and methods for controlling the load distribution between an engine and an energy storage device of a hybrid vehicle to control the temperature of the exhaust gas and thereby control the temperature of an SCR catalyst included in the aftertreatment system.

[0008] In some embodiments, a controller for controlling operation of a hybrid vehicle, the hybrid vehicle including an engine, an aftertreatment system, and an energy storage device, the aftertreatment system including a selective catalytic reduction (SCR) catalyst coupled to the engine, the controller being configured to be operably coupled to the engine, the energy storage device, and the aftertreatment system, the controller being configured to: estimate an exhaust gas temperature and an exhaust gas flow rate of exhaust gas received by the aftertreatment system from the engine based on a set of engine operating parameters, estimate an exhaust gas cooling rate of the SCR catalyst based on the estimated exhaust gas temperature, exhaust gas flow rate, and SCR catalyst temperature, determine an ambient cooling rate of the SCR catalyst based on an ambient temperature of an environment external to the aftertreatment system, a vehicle speed of the hybrid vehicle, and the SCR catalyst temperature, estimate a temperature change rate of the SCR catalyst based on the exhaust gas cooling rate and the ambient cooling rate, and adjust a load distribution between the engine and the energy storage device based on the SCR temperature change rate.

[0009] In some embodiments, the controller is further configured to: in response to determining that the SCR catalyst temperature is decreasing toward a low temperature threshold based on the rate of change of the SCR catalyst temperature, adjust the load distribution to increase the load on the engine. In some embodiments, the controller is further configured to: in response to determining that the SCR catalyst temperature is increasing toward a high temperature threshold based on the rate of change of the SCR catalyst temperature, adjust the load distribution to reduce the load on the engine.

[0010] In some embodiments, the controller is further configured to, in response to determining that the increase in the SCR catalyst temperature rate of change is greater than a rate increase threshold, increase a load on the energy storage device relative to the engine to reduce the SCR catalyst temperature rate of change.

[0011] In some embodiments, the set of engine parameters includes a speed of the engine, a torque demand from the engine, and a coolant temperature of coolant flowing through the engine.

[0012] In some embodiments, the aftertreatment system further includes an oxidation catalyst disposed upstream of the SCR catalyst, and the controller is configured to estimate the exhaust cooling rate further based on an oxidation catalyst temperature of the oxidation catalyst.

[0013] In some embodiments, the controller is further configured to instruct the reductant injection assembly to adjust the amount of reductant injected into the aftertreatment system. In some embodiments, the controller is further configured to, in response to determining that the SCR catalyst temperature is within the optimal operating range, adjust the load distribution based on load demand, desired fuel economy, the amount of remaining fuel, and / or the amount of remaining power in the energy storage device.

[0014] In some embodiments, a hybrid vehicle includes: an engine, an energy storage device, an aftertreatment system, and a controller, the aftertreatment system being fluidly coupled to the engine and configured to receive exhaust generated by the engine, the aftertreatment system including a selective catalytic reduction (SCR) catalyst, the SCR catalyst being configured to process components of the exhaust; a controller being operably coupled to the engine, the energy storage device, and the aftertreatment system, the controller being configured to: estimate an exhaust temperature and an exhaust flow rate of the exhaust based on a set of engine operating parameters, estimate an exhaust cooling rate of the exhaust based on the exhaust temperature, the exhaust flow rate, and the SCR catalyst temperature, determine an ambient cooling rate of the SCR catalyst based on an ambient temperature of an environment external to the aftertreatment system, a vehicle speed of the hybrid vehicle, and the SCR catalyst temperature, estimate a temperature change rate of the SCR catalyst based on the exhaust cooling rate and the ambient cooling rate, and adjust a load distribution between the engine and the energy storage device based on the temperature change rate of the SCR catalyst.

[0015] In some embodiments, the controller is configured to adjust the load distribution to increase the load on the engine in response to determining that the SCR catalyst temperature is decreasing toward a low temperature threshold based on the rate of change of the SCR catalyst temperature. In some embodiments, the controller is configured to adjust the load distribution to decrease the load on the engine in response to determining that the SCR catalyst temperature is increasing toward a high temperature threshold based on the rate of change of the SCR catalyst temperature.

[0016] In some embodiments, the controller is configured to, in response to determining that the rate of change of the SCR catalyst temperature increases by more than a rate increase threshold, increase a load on the energy storage device relative to the engine to reduce the rate of change of the SCR catalyst temperature.

[0017] In some embodiments, the set of engine parameters includes a speed of the engine, a torque demand from the engine, and a coolant temperature of coolant flowing through the engine.

[0018] In some embodiments, the aftertreatment system further includes an oxidation catalyst disposed upstream of the SCR catalyst, and the controller is configured to estimate the exhaust cooling rate further based on an oxidation catalyst temperature of the oxidation catalyst.

[0019] In some embodiments, the aftertreatment system includes a reductant injection assembly configured to inject a reductant into the aftertreatment system; and the controller is further configured to instruct the reductant injection assembly to adjust an amount of the reductant injected into the aftertreatment system.

[0020] In some embodiments, the controller is further configured to adjust the load distribution based on load demand, desired fuel economy, amount of remaining fuel, and / or amount of remaining power in the energy storage device in response to determining that the SCR catalyst temperature is within the optimal operating range.

[0021] In some embodiments, a method for controlling operation of a hybrid vehicle, the hybrid vehicle including an engine, an aftertreatment system, and an energy storage device, the aftertreatment system including a selective catalytic reduction (SCR) catalyst connected to the engine, the method comprising: estimating, by a controller of the hybrid vehicle, an exhaust gas temperature and an exhaust gas flow rate of exhaust gas received by the aftertreatment system from the engine based on a set of engine operating parameters; estimating, by the controller, an exhaust gas cooling rate of the SCR catalyst based on the estimated exhaust gas temperature, exhaust gas flow rate, and SCR catalyst temperature; determining, by the controller, an ambient cooling rate of the SCR catalyst based on an ambient temperature of an environment external to the aftertreatment system, a vehicle speed of the hybrid vehicle, and the SCR catalyst temperature; estimating, by the controller, a temperature change rate of the SCR catalyst based on the exhaust gas cooling rate and the ambient cooling rate; and adjusting, by the controller, a load distribution between the engine and the energy storage device based on the SCR temperature change rate.

[0022] In some embodiments, the method further comprises: in response to the controller determining that the SCR catalyst temperature is decreasing toward a low temperature threshold based on the SCR catalyst temperature change rate, adjusting the load distribution by the controller to increase the load on the engine. In some embodiments, the method further comprises: in response to the controller determining that the SCR catalyst temperature is increasing toward a high temperature threshold based on the SCR catalyst temperature change rate, adjusting the load distribution by the controller to reduce the load on the engine.

[0023] In some embodiments, a controller for controlling operation of a hybrid vehicle includes an engine, an aftertreatment system, and an energy storage device, the aftertreatment system including a selective catalytic reduction (SCR) catalyst coupled to the engine, the controller being configured to be operably coupled to the engine, the energy storage device, and the aftertreatment system, the controller being configured to: estimate an exhaust cooling rate of the SCR catalyst; determine or estimate an ambient cooling rate of the SCR catalyst; estimate a temperature change rate of the SCR catalyst based on the exhaust cooling rate and the ambient cooling rate; and adjust a load distribution between the engine and the energy storage device based on the SCR temperature change rate.

[0024] It should be appreciated that all combinations of the foregoing concepts and the additional concepts discussed in more detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the subject matter disclosed herein. In particular, all combinations of the subject matter claimed in this disclosure are contemplated as being part of the subject matter disclosed herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and other features of the present disclosure will become more fully apparent from the following description and appended claims taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several implementations according to the present disclosure and are therefore not to be considered limiting of its scope, the present disclosure will be described with additional specificity and detail through use of the accompanying drawings.

[0027] Figure 1 is a schematic diagram of a hybrid vehicle including an aftertreatment system according to an embodiment.

[0028] Figure 2 According to the embodiment, it can be included in Figure 1 Schematic block diagram of a controller in a hybrid vehicle.

[0029] Figure 3A-Figure 3B is a schematic flow chart of a method for controlling operation of a hybrid vehicle according to an embodiment.

[0030] In the following detailed description, reference is made to the accompanying drawings. In the drawings, similar symbols generally identify similar components, unless the context dictates otherwise. The illustrative implementations described in the detailed description, drawings, and claims are not meant to be limiting. Other implementations may be used, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the various aspects of the disclosure, as generally described herein and illustrated in the drawings, may be arranged, substituted, combined, and designed in a variety of different configurations, all of which are expressly contemplated and form a part of this disclosure.

[0031] Detailed description

[0032] The embodiments described herein generally relate to systems and methods for controlling the temperature of an aftertreatment system included in a hybrid vehicle, and more particularly to systems and methods for controlling the load distribution between an engine and an energy storage device of a hybrid vehicle to control the exhaust gas temperature, and thereby to an SCR catalyst included in the aftertreatment system.

[0033] As CO2 and greenhouse gas regulations become increasingly stringent, hybrid vehicle systems are expected to become increasingly common. A hybrid vehicle includes an engine and an energy storage device, and distributes load between the engine and the energy storage device to optimize its fuel efficiency. Such a hybrid vehicle system includes an aftertreatment system that may include an SCR catalyst configured to treat components of exhaust gas generated by the engine.

[0034] The catalytic conversion efficiency of the SCR catalyst depends on the operating temperature of the SCR catalyst, which is generally based on the temperature of the exhaust gas flowing through it. For example, the SCR catalyst generally has sufficient catalytic conversion efficiency at an SCR catalyst temperature greater than 200 degrees Celsius to provide NO reduction. x gas to meet stringent NO x However, the catalytic conversion efficiency of the SCR catalyst may begin to decrease at a relatively high temperature (eg, a temperature greater than 400 degrees Celsius).

[0035] Typically, the working cycle of the engine in a hybrid vehicle has a large amount of transient operation, resulting in the aftertreatment system continuously undergoing warm-up and cool-down periods. During the light load working cycle, the SCR catalyst temperature of the SCR catalyst decreases because the hybrid vehicle draws load primarily from its energy storage device to maximize fuel economy. In such cases (e.g., when idling or without transients), with low load, no load, or negative load on the engine (e.g., during driving), the temperature of the SCR catalyst may drop below the optimal operating temperature range of the SCR catalyst (e.g., between 200 degrees Celsius and 400 degrees Celsius). This results in a decrease in the catalytic conversion efficiency of the SCR catalyst and an increase in the amount of exhaust gas emitted by the aftertreatment system. Similarly, under high engine load conditions, the exhaust gas temperature, and therefore the SCR catalyst temperature, may increase above the optimal operating temperature, which may also result in a decrease in the catalytic conversion efficiency of the SCR catalyst.

[0036] In addition, NO from the aftertreatment system x Gas emissions can also vary depending on the operating conditions of the hybrid vehicle. For example, some hybrid vehicles can be used to transport goods to a terminal or distribution center. To reach the destination, the hybrid vehicle can travel on urban highways, local roads, and small roads leading to the terminal, slowing or crawling when queuing at the terminal, and returning along the same route. If the vehicle is hauling with only the engine running, the NO emissions from the aftertreatment system will be much higher. x The amount of gas varies depending on the location of the vehicle and the operating conditions. For example, the total NO x Of the emissions, about 19% may be emitted on urban roads, about 20% may be emitted on local roads, about 28% may be emitted at ports near docks, and about 24% may be emitted while traveling slowly in queues.

[0037] In contrast, various embodiments of the systems and methods described herein for controlling operation of a hybrid vehicle may provide one or more advantages, including, for example: (1) suppressing a decrease in SCR catalyst temperature so that the SCR catalyst temperature remains above a low-temperature threshold, thereby suppressing a decrease in the catalytic conversion efficiency of the SCR system; (2) suppressing an increase in SCR catalyst temperature so that the SCR catalyst temperature remains below a high-level threshold, thereby suppressing a decrease in catalytic conversion efficiency at high temperatures; (3) slowing the thermal ramp of the SCR catalyst as it transitions from light load to medium / high load to reduce thermal stress and damage to the SCR catalyst; (4) reducing the release of ammonia from the SCR catalyst at high temperatures, thereby reducing ammonia slip; (5) maintaining the catalytic conversion efficiency of the SCR catalyst while still providing high fuel economy; and (6) distributing the load between the engine and the energy storage device based on the location of the hybrid vehicle on its route to reduce NO x emission.

[0038] Figure 1 1 is a schematic diagram of a hybrid vehicle 1 according to an embodiment. The hybrid vehicle 1 includes an engine 10, an energy storage device 20, a transmission 30, an aftertreatment system 100, and a controller 170, and may include any other components (not shown) as required for the operation of the vehicle 1.

[0039] Engine 10 may include, for example, a diesel engine, a gasoline engine, a natural gas engine, a dual-fuel engine, a biodiesel engine, an E-85 engine, or any other suitable internal combustion engine. In some embodiments, engine 10 includes a diesel engine. Engine 10 combusts fuel and produces gases including NO x , CO, CO2 and other components of waste gas.

[0040] The energy storage device 20 may include one or more batteries (e.g., high voltage batteries, lead acid batteries, lithium ion batteries, etc.), one or more capacitors (e.g., supercapacitors, etc.), and / or any other energy storage devices, or a combination thereof. The energy storage device 20 may be configured to provide stored electrical energy to: (i) any vehicle subsystem of the hybrid vehicle 1 to operate various electrically powered components of the hybrid vehicle 1 (e.g., when the engine 10 is operating, when the engine 10 is off, etc.), (ii) an electromagnetic device (not shown) that may be included in the vehicle 1 to start the engine 10 (e.g., in response to a restart command after a stop-start feature shuts down the engine 10, when the operator turns the engine 10 on, etc.), and / or (iii) an electromagnetic device to facilitate providing a mechanical output to the transmission 30 (e.g., to drive the vehicle 1, etc.).

[0041] The transmission 30 can be configured as any type of transmission, such as a continuously variable transmission (CVT), a manual transmission, an automatic transmission, an automated manual transmission, a dual clutch transmission, etc. Thus, when the transmission changes from a geared transmission to a continuously variable configuration (e.g., a CVT), the transmission 30 can include various settings (gears, for a geared transmission) that affect different output speeds based on the input speed received thereby. The transmission 30 selectively receives mechanical power from the engine 10 and / or the energy storage device 20 (e.g., an electromagnetic device coupled to the energy storage device 20) to drive the hybrid vehicle 1.

[0042] The aftertreatment system 100 is connected to the engine 10. The aftertreatment system 100 is configured to receive exhaust gas from the engine 10 and process components of the exhaust gas (such as decomposing NO included in the exhaust gas). x Gas). The aftertreatment system 100 includes a housing 101 defining an internal volume, and an SCR catalyst 150 disposed within the internal volume. In various embodiments, the aftertreatment system 100 may further include an oxidation catalyst 130, a filter 140, and an ammonia oxidation (AMO) catalyst disposed within the housing 101. x ) catalyst 160. Housing 101 may be formed of a rigid, heat-resistant, and corrosion-resistant material, such as stainless steel, iron, aluminum, metal, ceramic, or any other suitable material. Housing 101 may have any suitable cross-section, such as circular, square, rectangular, oval, oblong, polygonal, or any other suitable shape.

[0043] An inlet conduit 102 is fluidly connected to an inlet of the housing 101 and is configured to receive exhaust gas from the engine 10 and communicate the exhaust gas to the interior volume defined by the housing 101. Additionally, an outlet conduit 104 may be connected to an outlet of the housing 101 and is configured to discharge treated exhaust gas into the environment (e.g., treated to remove particulate matter such as soot and / or reduce gases such as NOx included in the exhaust gas). x exhaust gas components such as gases, CO, and unburned hydrocarbons).

[0044] The first sensor 103 may be positioned in the inlet conduit 102. The first sensor 103 may include a NO x sensor, the NO x The sensor is configured to measure NO included in the exhaust gas flowing into the SCR catalyst 150. x In various embodiments, a temperature sensor, a pressure sensor, an oxygen sensor, or any other sensor may also be positioned in the inlet conduit 102 to determine one or more operating parameters of the exhaust gas flowing through the aftertreatment system 100 .

[0045] The second sensor 105 may be positioned in the outlet conduit 104. The second sensor 105 may include a second NO x sensor, the second NO x The sensor is configured to determine the NOx emitted to the environment after passing through the SCR catalyst 150. x In other embodiments, the second sensor 105 may include a particulate matter sensor configured to determine the amount of particulate matter (e.g., soot included in the exhaust gas leaving the filter 140) in the exhaust gas discharged into the environment. In other embodiments, the second sensor 105 may include an ammonia sensor configured to measure the amount of ammonia in the exhaust gas flowing out of the SCR catalyst 150, i.e., to determine ammonia slip. This can be used as a measure of the catalytic conversion efficiency of the SCR catalyst 150, to adjust the amount of reductant to be injected into the SCR catalyst 150, and / or to adjust the temperature of the SCR catalyst 150 so as to allow the SCR catalyst 150 to effectively use ammonia to catalytically decompose NO included in the exhaust gas flowing through. x Gas. AMO x Catalyst 160 may be located downstream of SCR catalyst 150 to decompose any unreacted ammonia in the exhaust gas downstream of SCR catalyst 150 .

[0046] The oxidation catalyst 130 may be located upstream of the SCR catalyst 150 and configured to decompose unburned hydrocarbons and / or CO included in the exhaust gas. In some embodiments, the oxidation catalyst 130 may include a diesel oxidation catalyst. The filter 140 is disposed downstream of the oxidation catalyst 130 and upstream of the SCR catalyst 150 and configured to remove particulate matter (e.g., soot, debris, inorganic particles, etc.) from the exhaust gas. In various embodiments, the filter 140 may include a ceramic filter. In some embodiments, the filter 140 may include a cordierite filter, which may be, for example, an asymmetric filter. In yet other embodiments, the filter 140 may be catalytically active.

[0047] As described herein, the SCR catalyst 150 is formulated to decompose exhaust gas components flowing through it in the presence of a reducing agent. In some embodiments, the SCR catalyst 150 may include a selective catalytic reduction filter (SCRF). Any suitable catalyst 150 may be used, such as a catalyst based on platinum, palladium, rhodium, cerium, iron, manganese, copper, vanadium (any other suitable catalyst, or a combination thereof). The SCR catalyst 150 can be disposed on a suitable substrate, such as a ceramic (e.g., cordierite) or metal (e.g., chromium aluminum cobalt heat-resistant steel (kanthal)) monolithic core, which can, for example, define a honeycomb structure. A washcoat can also be used as a carrier material for the SCR catalyst 150. Such a washcoat material can include, for example, aluminum oxide, titanium dioxide, silicon dioxide, any other suitable coating material, or a combination thereof.

[0048] Exhaust gas (eg, diesel exhaust) may flow through and / or around the SCR catalyst 150 such that any NO included in the exhaust gas is x The gas is further reduced to produce a substantially NO-free x The exhaust gas of the gas. The SCR catalyst inlet temperature sensor 153 can be positioned upstream of the SCR catalyst 150 and configured to determine the temperature of the exhaust gas entering the SCR catalyst 150. The SCR catalyst outlet temperature sensor 155 can also be positioned near the outlet of the SCR catalyst 150 and configured to measure the temperature of the exhaust gas leaving the SCR catalyst 150. The temperature of the exhaust gas measured at the inlet and outlet of the SCR catalyst 150 can be used to estimate the SCR catalyst temperature (e.g., the weighted temperature of the SCR catalyst 150). Additionally or alternatively, a temperature sensor (not shown) can also be disposed within the SCR catalyst 150 to measure the bed temperature of the SCR catalyst 150. In other embodiments, the SCR catalyst temperature can be estimated based on the exhaust gas temperature, the exhaust gas flow rate (e.g., at the inlet of the SCR catalyst 150), the physical properties of the SCR catalyst 150, and / or the size of the SCR catalyst 150. In some embodiments, multiple SCR catalyst temperatures measured or estimated at various points along the length of the SCR catalyst 150 may be used.

[0049] Although Figure 1 Only the oxidation catalyst 130, the filter 140, the SCR catalyst 150 and the AMO are shown within the interior volume defined by the housing 101. x In other embodiments, the catalyst 160 includes, in addition to the oxidation catalyst 130, the filter 140, the SCR catalyst 150, and the AMO xIn addition to catalyst 160, a variety of aftertreatment components may be located within the interior volume defined by housing 101. Such aftertreatment components may include, for example, mixers, baffles, secondary filters (e.g., secondary partial flow or catalytic filters), or any other suitable aftertreatment components.

[0050] The reductant port 156 may be positioned on a sidewall of the housing 101 and configured to allow the reductant to be injected therethrough into the interior volume defined by the housing 101. The reductant port 156 may be positioned upstream of the SCR catalyst 150 (e.g., allowing the reductant to be injected into the exhaust gas upstream of the SCR catalyst 150) or above the SCR catalyst 150 (e.g., allowing the reductant to be injected directly onto the SCR catalyst 150). In other embodiments, the reductant port 156 may be positioned on the inlet conduit 102 and configured to inject the reductant into the inlet conduit 102 upstream of the SCR catalyst 150. In such embodiments, a mixer, baffle, vane, or other structure may be positioned in the inlet conduit 102 to facilitate mixing of the reductant with the exhaust gas.

[0051] The reductant storage tank 110 is configured to store a reductant. The reductant is formulated to promote the reduction of exhaust gas components (eg, NO x Any suitable reducing agent may be used. In some embodiments, the exhaust gas comprises diesel exhaust and the reducing agent comprises a diesel exhaust treatment fluid. For example, the diesel exhaust treatment fluid may comprise urea, an aqueous solution of urea, or any other fluid comprising ammonia, a byproduct, or any other diesel exhaust treatment fluid known in the art (e.g., (a diesel exhaust treatment fluid sold under the name of urea). For example, the reductant can include an aqueous urea solution having a specific ratio of urea to water. In some embodiments, the reductant can include an aqueous urea solution comprising 32.5% urea by volume and 67.5% deionized water by volume, 40% urea by volume and 60% deionized water by volume, or any other suitable ratio of urea to deionized water.

[0052] The reductant injection assembly 120 is fluidly coupled to the reductant storage tank 110. The reductant injection assembly 120 is configured to selectively inject reductant into the SCR catalyst 150 or upstream thereof (e.g., into the inlet conduit 102) or into a mixer (not shown) located upstream of the SCR catalyst 150. The reductant injection assembly 120 may include various structures to facilitate receiving the reductant from the reductant storage tank 110 and delivering it to the SCR catalyst 150, such as a pump, a valve, a screen, a filter, etc.

[0053] The aftertreatment system 100 may also include a reductant injector fluidically coupled to the reductant injection assembly 120 and configured to inject a reductant (e.g., a combined flow of reductant and compressed air) into the SCR catalyst 150. In various embodiments, the reductant injector may include a nozzle having a predetermined diameter. In various embodiments, the reductant injector may be positioned in the reductant port 156 and configured to deliver a stream or jet of reductant into the interior volume of the housing 101 to deliver the reductant to the SCR catalyst 150.

[0054] The hybrid vehicle 1 may further comprise an ambient temperature sensor 107 configured to measure the ambient temperature of the environment external to the aftertreatment system.The vehicle 1 may further comprise a vehicle speed sensor 109 configured to determine the speed of the hybrid vehicle 1 .

[0055] The controller 170 is operatively coupled to the engine 10, the energy storage device 20, the ambient temperature sensor 107, the vehicle speed sensor 109, and the aftertreatment system 100, such as the SCR catalyst inlet temperature sensor 153 and the SCR catalyst outlet temperature sensor 155. The controller 170 may be communicatively coupled to the first sensor 103 and may be configured to receive a first sensor signal from the first sensor 103, for example, to determine NO included in the exhaust gas entering the aftertreatment system. x The controller 170 may also be communicatively coupled to the second sensor 105 and may be configured to determine the amount of NO included in the exhaust gas discharged into the environment. x The concentration of gas or ammonia. The controller 170 can be operably coupled to the engine 10, the energy storage device 20, the ambient temperature sensor 107, and the various components of the aftertreatment system 100 using any type and any number of wired or wireless connections. For example, the wired connection can include a serial cable, a fiber optic cable, a CAT5 cable, or any other form of wired connection. The wireless connection can include the Internet, Wi-Fi, cellular, radio, Bluetooth, ZigBee, etc. In one embodiment, a controller area network (CAN) bus provides for the exchange of signals, information, and / or data. The CAN bus includes any number of wired and wireless connections.

[0056] In some embodiments, the controller 170 may be configured to estimate the exhaust gas temperature and the exhaust flow rate of the exhaust gas based on a set of engine operating parameters. For example, the controller 170 may receive an engine operating parameter signal indicating the engine operating parameters from the engine 10. The controller 170 interprets the engine operating parameter signal and determines the exhaust gas temperature and flow rate therefrom, for example, using an equation, algorithm, or lookup table provided in the controller 170. The set of engine operating parameters may include, but is not limited to, the engine speed of the engine 10, the load demand (e.g., torque demand) from the engine 10, and the coolant temperature of the coolant of the engine 10. The load demand may be determined based on the position of the throttle of the hybrid vehicle 1. In some embodiments, the controller 170 may also determine the exhaust gas temperature and flow rate based on the torque demand from the energy storage device 20.

[0057] The controller 170 is configured to estimate the exhaust gas cooling rate of the SCR catalyst 150 based on the estimated exhaust gas temperature, exhaust gas flow rate, and SCR catalyst temperature. For example, the controller 170 may receive SCR inlet temperature and SCR outlet temperature signals from the SCR catalyst inlet temperature sensor 153 and the SCR catalyst outlet temperature sensor 155 and estimate the SCR catalyst temperature therefrom. The controller 170 may include equations, algorithms, and / or lookup tables to determine the exhaust gas cooling rate based on the exhaust gas temperature and flow rate and the SCR catalyst temperature. In some embodiments, the controller 170 may be configured to also determine the exhaust gas cooling rate based on the oxidation catalyst temperature of the oxidation catalyst 130 and / or the filter temperature of the filter 140. The exhaust gas cooling rate indicates the rate at which the exhaust gas, and therefore the SCR catalyst 150, cools, for example, due to a low load on the engine 10 or when the hybrid vehicle 1 is powered solely by the energy storage device 20. In some embodiments, the exhaust gas cooling rate may be determined while the hybrid vehicle 1 is operating solely with the engine 10.

[0058] The controller 170 is also configured to determine an ambient cooling rate for the SCR catalyst 150 based on the ambient temperature, the vehicle speed of the hybrid vehicle 1, and the SCR catalyst temperature. For example, the temperature of the surrounding environment and how fast the hybrid vehicle 1 is traveling (indicating the speed at which air is blown through the aftertreatment system 100) are also contributing factors in determining the ambient cooling rate for the SCR catalyst 150 (i.e., air cooling of the SCR catalyst 150). In some embodiments, the ambient cooling rate may be determined while the hybrid vehicle 1 is operating solely with the energy storage device 20.

[0059] The controller 170 is configured to determine an SCR catalyst temperature change rate based on the exhaust gas cooling rate and the ambient cooling rate. The SCR catalyst temperature change rate indicates the rate at which the SCR catalyst temperature increases or decreases. This can be used to predict how quickly the SCR catalyst temperature will drop below a low-temperature threshold (e.g., 200 degrees Celsius) or rise above a high-temperature threshold (e.g., 400 degrees Celsius).

[0060] The controller 170 is configured to adjust the load distribution between the engine 10 and the energy storage device 20 based on the SCR catalyst temperature change rate. For example, the controller 170 may use the SCR catalyst temperature change rate to determine whether the temperature of the SCR catalyst is decreasing toward a low temperature threshold (e.g., 10 degrees Celsius greater than the low temperature threshold), at which the catalytic conversion efficiency of the SCR catalyst 150 drops below the minimum allowable catalytic conversion efficiency of the SCR catalyst 150 (e.g., 90% catalytic conversion efficiency). In response to determining that the SCR catalyst is approaching the low temperature threshold based on the SCR catalyst temperature change rate, the controller 170 may be configured to adjust the load distribution to increase the load on the engine 10. For example, in response to determining that the temperature of the SCR catalyst 150 will reach the low temperature threshold within a time period equal to or less than 0.1 minutes to 3 minutes, the controller 170 may increase the percentage of load (e.g., torque %) drawn from the engine 10 relative to the energy storage device 20. The increased load on the engine 10 increases the amount of fuel consumed by the engine 10 and causes the temperature of the exhaust gas to increase, thereby causing the temperature of the SCR catalyst 150 to increase.

[0061] In addition, in response to determining that the SCR catalyst temperature is increasing toward a high temperature threshold (e.g., 400 degrees Celsius) based on the rate of change of the SCR catalyst temperature, the controller 170 is configured to adjust the load distribution to reduce the load on the engine 10. For example, the high temperature threshold may correspond to a temperature at which the SCR catalyst 150 experiences a release of stored ammonia while experiencing a decrease in its catalytic conversion efficiency and / or the release of stored ammonia results in ammonia slip. In response to determining that the SCR catalyst temperature is approaching the high temperature threshold based on the rate of change of the SCR catalyst temperature, the controller 170 may be configured to adjust the load distribution to reduce the load on the engine 10. For example, in response to determining that the temperature of the SCR catalyst 150 will reach the high temperature threshold within a period of time equal to or less than 1 minute, the controller 170 may reduce the percentage (e.g., torque %) of power drawn from the engine 10 relative to the energy storage device 20. The reduced load on the engine 10 reduces fuel consumption and results in a reduction in the temperature of the exhaust gas, thereby resulting in a reduction in the temperature of the SCR catalyst 150.

[0062] In addition, the controller 170 may be configured to inhibit excessive temperature increases in the SCR catalyst 150. For example, when the engine 10 transitions from a light load to a medium / high load, the SCR catalyst 150 may experience a substantial increase in temperature, causing the SCR catalyst 150 to release stored ammonia, which may result in ammonia slip. In some embodiments, in response to determining that an increase in the rate of change of the SCR catalyst temperature (e.g., based on a throttle command of the vehicle 1 and / or temperature changes in upstream components such as the oxidation catalyst 130 and / or the filter 140) is greater than a rate increase threshold (e.g., greater than 50 degrees Celsius / minute to 200 degrees Celsius / minute), the controller 170 may be configured to increase the load on the energy storage device 20 relative to the engine 10 to reduce the rate of change of the SCR catalyst temperature. This may occur when the hybrid vehicle 1 transitions from a light load to a medium load or a high load. In some embodiments, the controller 170 is configured to increase the load on the energy storage device 20 relative to the engine 10 to reduce the rate of change of the SCR catalyst temperature. x When the catalyst 160 is at a sufficient lightoff temperature, the load on the engine 10 is increased when the inlet temperature of the SCR catalyst 150 is below 300 degrees Celsius.

[0063] The controller 170 suppresses a sharp increase in the temperature of the SCR catalyst, thereby reducing thermal stress and damage to the SCR catalyst 150. In some embodiments, the controller 170 may also instruct the reductant injection assembly 120 to adjust the amount of reductant injected into the aftertreatment system 100 based on the rate of change of the SCR catalyst temperature, for example, to allow ammonia stored in the SCR catalyst 150 to be depleted before being desorbed due to the increase in the SCR catalyst temperature. In some embodiments, in addition to temperature management, the controller 170 may be configured to increase the load on the engine 10 or adjust the air / fuel ratio of the engine 10 to increase the NO in the exhaust gas emitted by the engine 10. x The amount of gas. NO added to the exhaust gas x Ammonia released from the SCR catalyst 150 is consumed at high temperatures, thereby reducing ammonia slip.

[0064] In some embodiments, in response to determining that the SCR catalyst temperature is within an optimal operating range (e.g., between 200 degrees Celsius and 400 degrees Celsius), controller 170 may be configured to adjust the load distribution based on load demand, desired fuel economy, the amount of remaining fuel, and / or the amount of remaining power in energy storage device 20. This may correspond to normal operation of the aftertreatment system. In this case, controller 170 may adjust the percentage of load drawn from engine 10 relative to energy storage device 20 to maximize fuel economy.

[0065] In some embodiments, the controller 170 may also be configured to adjust the load distribution between the engine 10 and the energy storage device 20 based on the load demand from the hybrid vehicle, the location of the hybrid vehicle 1 on the route, and / or the speed of the hybrid vehicle 1. For example, when there is a low load on the hybrid vehicle 1, or the hybrid vehicle 1 is at a port near a pier, or the speed of the hybrid vehicle 1 (e.g., as determined by the vehicle speed sensor 109) is below a low threshold (e.g., less than 40 miles per hour), the controller 10 may be configured to operate the hybrid vehicle 1 using only the energy storage device 20. Since a large amount of NO is generated under low load conditions or at low speeds, the energy storage device 20 may be used to store and operate the hybrid vehicle 1. x (For example, in ports near docks or in queues at docks, slow traffic or idling at low loads, NO x The amount of NOx emissions is greater than 50%), so operating the hybrid vehicle 1 with only the energy storage device 20 eliminates the NOx emissions of the hybrid vehicle. x However, in some cases, the controller 170 may be configured to start the engine 10 during such operating conditions, for example, in response to the power stored in the energy storage device 20 dropping below a threshold, or based on the rate of change of the temperature of the SCR catalyst, as previously described herein. In some embodiments, for example, an electric heater (not shown) may be used to heat the SCR catalyst 150 to maintain the temperature of the SCR catalyst 150 above a low temperature threshold during such conditions, or any other suitable cold start technique may be used.

[0066] The controller 170 can be configured to balance the load between the engine 10 and the energy storage device 20 when driving under high load conditions, or when driving at moderate speeds (e.g., between 40-55 mph) when power from the engine 10 may be desired. This situation may occur when the hybrid vehicle 1 is driving on a local road or climbing a hill on an urban highway. The engine 10 is used to increase the temperature of the exhaust gas, thereby heating the SCR catalyst 150, increasing its catalytic conversion efficiency, and charging the energy storage device. The controller 170 can also be configured to operate the hybrid vehicle 1 at high speeds (e.g., greater than 55 mph), such as when driving on an urban highway. The energy storage device 20 can be charged, for example, for use during future high load conditions. At high speeds, the fuel economy of the engine 10 is higher while providing sufficient power to the hybrid vehicle 1 to maintain high speeds. In addition, the SCR catalyst 150 is at a sufficient temperature to reduce NO at high catalytic conversion efficiency. x In some embodiments, the controller 170 may also be configured to increase or decrease the load on the engine 10 in order to control the NO in the exhaust gas emitted by the engine 10. xThe amount of gas, for example, is to obtain a desired SCR catalytic conversion efficiency.

[0067] In some embodiments, the controller 170 may include various components and modules configured to perform the operations of the controller 170. For example, Figure 2 is a schematic block diagram of a controller 170 according to an embodiment. Controller 170 may include a processor 172, a memory 174 or any other computer-readable medium, and a communication interface 176. Furthermore, controller 170 includes exhaust parameter determination circuitry 174a, exhaust cooling rate determination circuitry 174c, ambient cooling rate determination circuitry 174d, load distribution control circuitry 174e, and, in some embodiments, energy storage device (ESD) torque demand determination circuitry 174b. It should be understood that controller 170 illustrates only one embodiment of controller 170, and any other controller capable of performing the operations described herein may be used.

[0068] The processor 172 may include a microprocessor, a programmable logic controller (PLC) chip, an ASIC chip, or any other suitable processor. The processor 172 communicates with the memory 174 and is configured to execute instructions, algorithms, commands, or other programs stored in the memory 174.

[0069] The memory 174 includes any of the memory and / or storage components discussed herein. For example, the memory 174 may include RAM and / or cache memory of the processor 172. The memory 174 may also include one or more storage devices (e.g., a hard drive, a flash drive, a computer-readable medium, etc.) that are local or remote to the controller 170. The memory 174 is configured to store lookup tables, algorithms, or instructions.

[0070] In one configuration, the exhaust parameter determination circuit 174a, the ESD torque demand determination circuit 174b, the exhaust cooling rate determination circuit 174c, the ambient cooling rate determination circuit 174d, and the load distribution control circuit 174e are embodied as a machine- or computer-readable medium (e.g., stored in memory 174) that is executable by a processor, such as processor 172. As described herein and for other purposes, the machine-readable medium (e.g., memory 174) facilitates the execution of certain operations to enable the reception and transmission of data. For example, the machine-readable medium may provide instructions (e.g., commands, etc.) to, for example, acquire data. In this regard, the machine-readable medium may include programmable logic that defines the frequency of data acquisition (or data transmission). Thus, the computer-readable medium may include code written in any programming language, including, but not limited to, Java and any conventional procedural programming language, such as the "C" programming language or similar programming languages. The computer-readable program code may be executed on one processor or on one or more remote processors. In the latter case, the remote processors may be interconnected via any type of network (e.g., a CAN bus, etc.).

[0071] In another configuration, the exhaust parameter determination circuit 174a, the ESD torque demand determination circuit 174b, the exhaust cooling rate determination circuit 174c, the ambient cooling rate determination circuit 174d, and the load distribution control circuit 174e are implemented as a hardware unit, such as an electronic control unit. Thus, the exhaust parameter determination circuit 174a, the ESD torque demand determination circuit 174b, the exhaust cooling rate determination circuit 174c, the ambient cooling rate determination circuit 174d, and the load distribution control circuit 174e may be implemented as one or more circuit components, including but not limited to processing circuitry, network interfaces, peripheral devices, input devices, output devices, sensors, and the like.

[0072] In some embodiments, the exhaust parameter determination circuit 174a, the ESD torque demand determination circuit 174b, the exhaust cooling rate determination circuit 174c, the ambient cooling rate determination circuit 174d, and the load distribution control circuit 174e can take the form of one or more analog circuits, electronic circuits (e.g., integrated circuits (ICs), discrete circuits, system-on-chip (SOCs) circuits, microcontrollers, etc.), telecommunications circuits, hybrid circuits, and any other type of "circuitry." In this regard, the exhaust parameter determination circuit 174a, the ESD torque demand determination circuit 174b, the exhaust cooling rate determination circuit 174c, the ambient cooling rate determination circuit 174d, and the load distribution control circuit 174e can include any type of components for performing or facilitating the operations described herein. For example, the circuits described herein can include one or more transistors, logic gates (e.g., NAND, AND, NOR, OR, XOR, NOT, XNOR, etc.), resistors, multiplexers, registers, capacitors, inductors, diodes, wiring, etc.

[0073] Therefore, the exhaust parameter determination circuit 174a, the ESD torque demand determination circuit 174b, the exhaust cooling rate determination circuit 174c, the ambient cooling rate determination circuit 174d, and the load distribution control circuit 174e may also include programmable hardware devices, such as field programmable gate arrays, programmable array logic, programmable logic devices, etc. In this regard, the exhaust parameter determination circuit 174a, the ESD torque demand determination circuit 174b, the exhaust cooling rate determination circuit 174c, the ambient cooling rate determination circuit 174d, and the load distribution control circuit 174e may include one or more memory devices for storing instructions executable by the processors of the exhaust parameter determination circuit 174a, the ESD torque demand determination circuit 174b, the exhaust cooling rate determination circuit 174c, the ambient cooling rate determination circuit 174d, and the load distribution control circuit 174e. The one or more memory devices and the processor may have the same definitions as provided below for the memory 174 and the processor 172.

[0074] In the example shown, the controller 170 includes a processor 172 and a memory 174. The processor 172 and the memory 174 may be constructed or configured to execute or implement the instructions, commands, and / or control processes described herein with respect to the exhaust parameter determination circuit 174a, the ESD torque demand determination circuit 174b, the exhaust cooling rate determination circuit 174c, the ambient cooling rate determination circuit 174d, and the load distribution control circuit 174e. Thus, the described configuration represents the exhaust parameter determination circuit 174a, the ESD torque demand determination circuit 174b, the exhaust cooling rate determination circuit 174c, the ambient cooling rate determination circuit 174d, and the load distribution control circuit 174e as embodied in a machine or computer-readable medium. However, as described above, this illustration is not meant to be limiting, as the present disclosure contemplates other embodiments, such as the aforementioned embodiments, in which the exhaust parameter determination circuit 174a, the ESD torque demand determination circuit 174b, the exhaust cooling rate determination circuit 174c, the ambient cooling rate determination circuit 174d, and the load distribution control circuit 174e, or at least one of the exhaust parameter determination circuit 174a, the ESD torque demand determination circuit 174b, the exhaust cooling rate determination circuit 174c, the ambient cooling rate determination circuit 174d, and the load distribution control circuit 174e, is configured as a hardware unit. All such combinations and variations are intended to fall within the scope of the present disclosure.

[0075] The processor 172 may be implemented as one or more general-purpose processors, application-specific integrated circuits (ASICs), one or more field-programmable gate arrays (FPGAs), a digital signal processor (DSP), a group of processing components, or other suitable electronic processing components. In some embodiments, one or more processors may be shared by multiple circuits (e.g., the exhaust parameter determination circuit 174a, the ESD torque demand determination circuit 174b, the exhaust cooling rate determination circuit 174c, the ambient cooling rate determination circuit 174d, and the load distribution control circuit 174e), may include or otherwise share the same processor, and in some example embodiments, the processor may execute instructions stored or otherwise accessed via different areas of memory. Alternatively or additionally, one or more processors may be configured to perform certain operations independently of one or more coprocessors or otherwise perform certain operations. In other example embodiments, two or more processors may be connected via a bus to enable independent, parallel, pipelined, or multi-threaded instruction execution. All of these variations are intended to fall within the scope of the present disclosure. The memory 174 (e.g., RAM, ROM, flash memory, hard disk storage, etc.) can store data and / or computer code for facilitating the various processes described herein. The memory 174 can be communicatively coupled to the processor 172 to provide computer code or instructions to the processor 172 for performing at least some of the processes described herein. Furthermore, the memory 174 can be or include tangible, non-transitory volatile memory or non-volatile memory. Thus, the memory 174 can include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described herein.

[0076] The communication interface 176 may include a wireless interface (e.g., a jack, an antenna, a transmitter, a receiver, a communication interface, a wired terminal, etc.) for communicating data with various systems, devices, or networks. For example, the communication interface 176 may include an Ethernet card and port for sending and receiving data via an Ethernet-based communication network and / or a Wi-Fi communication interface for communicating with the engine 10, the energy storage device 20, the first sensor 103, the second sensor 105, the ambient temperature sensor 107, the vehicle speed sensor 109, and the temperature sensors 153 and 155. The communication interface 176 may be configured to communicate via a local area network or a wide area network (e.g., the Internet, etc.) and may use various communication protocols (e.g., IP, LON, Bluetooth, ZigBee, radio, cellular, near field communication, etc.).

[0077] Exhaust parameter determination circuit 174a is configured to receive a set of engine operating parameter signals from engine 10 and determine exhaust gas temperature and exhaust gas flow rate therefrom. For example, exhaust parameter determination circuit 174a may receive an engine torque demand signal (e.g., from the throttle of hybrid vehicle 1), an engine speed signal, and, in some embodiments, a coolant temperature signal from engine 10, and determine exhaust gas temperature and flow rate therefrom. In some embodiments, exhaust parameter determination circuit 174a may also receive an ESD torque demand signal from ESD torque demand determination circuit 174b to determine the total torque required by hybrid vehicle 1, and use the total torque demand to determine exhaust gas temperature and flow rate.

[0078] The ESD torque demand determination circuit 174b receives an ESD load percentage signal from the load distribution control circuit 174e, which indicates the percentage of the load (e.g., torque) provided by the energy storage device 20 for providing the hybrid vehicle 1. As previously described herein, the ESD torque demand determination circuit 174b determines the torque demand of the ESD and transmits the ESD torque demand signal to the exhaust parameter determination circuit 174a.

[0079] The exhaust gas cooling rate determination circuit 174c receives the exhaust gas temperature signal and the exhaust gas flow rate signal from the exhaust gas parameter determination circuit 174a. The exhaust gas cooling rate determination circuit 174c also receives the SCR catalyst temperature signal (e.g., from the SCR catalyst inlet and outlet temperature sensors 153 and 155) and determines the exhaust gas cooling rate of the SCR catalyst 150 based on the exhaust gas temperature, the exhaust gas flow rate, and the SCR catalyst temperature. In some embodiments, the exhaust gas cooling rate determination circuit 174c may be configured to determine the exhaust gas cooling rate based on the oxidation catalyst temperature of the oxidation catalyst 130 and / or the filter temperature of the filter 140.

[0080] The ambient cooling rate determination circuit 174d is configured to determine the ambient cooling rate of the SCR catalyst 150. For example, the ambient cooling rate determination circuit 174d receives the SCR catalyst temperature signal, the ambient temperature signal representing the ambient temperature from the ambient temperature sensor 107, and the vehicle speed signal from the vehicle speed sensor 109, and determines the ambient cooling rate accordingly.

[0081] The load distribution control circuit 174e receives the exhaust cooling rate from the exhaust cooling rate determination circuit 174c and the ambient cooling rate signal from the ambient cooling rate determination circuit 174d, and determines the SCR catalyst temperature change rate accordingly. Based on the SCR catalyst temperature change rate, the load distribution control circuit 174e generates an ESD load percentage signal that is transmitted to the energy storage device 20 (or an electromagnetic device coupled to the energy storage device 20), and an engine load percentage signal that is transmitted to the engine 10. Each load percentage signal adjusts the load distribution between the engine 10 and the energy storage device 20 to suppress a decrease in the SCR catalyst temperature below a low temperature threshold, an increase in the SCR catalyst temperature above a high temperature threshold, and / or a sudden increase in the SCR catalyst temperature change rate.

[0082] Figure 3A-Figure 3B A schematic flow chart of an example method 200 for controlling the operation of a hybrid vehicle according to an embodiment is illustrated. A hybrid vehicle (e.g., hybrid vehicle 1) includes an engine (e.g., engine 10), an energy storage device (e.g., energy storage device 20), and an aftertreatment system (e.g., aftertreatment system 100). The hybrid vehicle may include a controller (e.g., controller 170) configured to adjust the load distribution between the engine and the energy storage device to allow an SCR catalyst (e.g., SCR catalyst 150) included in the aftertreatment system to operate with optimal catalytic conversion efficiency. Although described with respect to vehicle 1 and controller 170, the operations of method 200 may be performed with any other suitable controller or used in any other hybrid vehicle.

[0083] Method 200 includes determining, at 202, by controller 170, an exhaust gas temperature and an exhaust gas flow rate of exhaust gas flowing through SCR catalyst 150 based on a set of engine operating parameters. The set of engine operating parameters may include, for example, a load or torque demand from engine 10, engine speed, and, in some embodiments, a coolant temperature of a coolant of engine 10.

[0084] At 204, the controller 170 determines an exhaust cooling rate for the SCR catalyst based on the determined exhaust temperature, exhaust flow rate, and the SCR catalyst 150. The exhaust cooling rate indicates the rate at which the exhaust, and thus the SCR catalyst 150, cools, for example due to a low load on the engine 10 or the hybrid vehicle 1 being powered only by the energy storage device 20.

[0085] At 206 , the controller 170 determines an ambient cooling rate for the SCR catalyst 150 based on the ambient temperature (eg, measured by the ambient temperature sensor 107 ), the vehicle speed (eg, determined by the vehicle speed sensor 109 ), and the SCR catalyst temperature.

[0086] At 208 , the controller 170 determines a rate of change of the SCR catalyst temperature of the SCR catalyst 150 based on the exhaust cooling rate and the ambient cooling rate.

[0087] At 210 , the controller 170 determines whether the SCR catalyst temperature is approaching a low temperature threshold (e.g., 200 degrees Celsius) based on the rate of change of the SCR catalyst temperature. In response to determining that the SCR catalyst temperature is approaching the low temperature threshold ( 210 : YES), the controller 170 adjusts the load distribution between the engine 10 and the energy storage device 20 at 212 to increase the load on the engine 10. As previously described, this increases the exhaust gas temperature, thereby heating the SCR catalyst 150.

[0088] In response to determining that the SCR catalyst temperature is not approaching the low temperature threshold ( 210 : NO), method 200 proceeds to operation 214 where the controller 170 determines whether the SCR catalyst is approaching a high temperature threshold based on the rate of change of the SCR catalyst temperature. In response to determining that the SCR catalyst temperature is approaching the high temperature threshold ( 214 : YES), the controller 170 adjusts the load distribution at 216 to reduce the load on the engine 10, for example, by increasing the load on the energy storage device 20.

[0089] In response to determining that the SCR catalyst temperature is not approaching the high temperature threshold ( 214 : No), method 200 proceeds to operation 218 where the controller 170 determines whether the rate of change of the SCR catalyst temperature is greater than a rate threshold (e.g., greater than 50 degrees Celsius per minute to 200 degrees Celsius per minute). In response to determining that the rate of change of the SCR catalyst temperature is greater than the rate threshold ( 218 : Yes), at 220 , the controller 170 adjusts the load distribution to increase the load on the energy storage device 20 relative to the engine 10.

[0090] In some embodiments, in response to determining that the SCR catalyst temperature is within an optimal operating range (e.g., between 250 degrees Celsius and 550 degrees Celsius), at 222, the controller 170 may be configured to adjust the load distribution based on the load demand, desired fuel economy, the amount of remaining fuel, and / or the amount of remaining power in the energy storage device 20. This may correspond to operation of the aftertreatment system at its optimal catalytic conversion efficiency (e.g., greater than 90% efficiency). In this case, the controller 170 may adjust the percentage of load drawn from the engine 10 relative to the energy storage device 20 in order to maximize fuel economy.

[0091] It should be noted that the term "example," as used herein to describe various embodiments, is intended to indicate that such embodiments are possible examples, representatives and / or illustrations of possible embodiments (and such terms are not intended to imply that such embodiments are necessarily particular or excellent examples).

[0092] As used herein, the terms "about" and "approximately" generally refer to plus or minus 10% of the stated value. For example, about 0.5 would include 0.45 and 0.55, about 10 would include 9 to 11, and about 1000 would include 900 to 1100.

[0093] As used herein, the term "coupled" or the like refers to the connection of two components directly or indirectly to one another. Such connection may be fixed (e.g., permanent) or movable (e.g., removable or releasable). Such connection may be achieved by the two components, or the two components and any additional intermediate components, being integrally formed as a single unitary body with one another, or by the two components, or the two components and any additional intermediate components, being connected to one another.

[0094] It is important to note that the structure and arrangement of the various exemplary embodiments are illustrative only. Although only a few embodiments are described in detail in this disclosure, those skilled in the art who review this disclosure will readily recognize that many modifications (e.g., changes in the size, dimensions, structure, shape and proportion of the various elements, the values ​​of the parameters, the mounting arrangements, the use of materials, the colors, the orientations, etc.) are possible without substantially departing from the novel teachings and advantages of the subject matter described herein. Furthermore, it should be understood that features from one embodiment disclosed herein can be combined with features of other embodiments disclosed herein, as will be understood by those of ordinary skill in the art. Other substitutions, modifications, changes, and omissions may also be made in the design, operating conditions, and arrangement of the various exemplary embodiments without departing from the scope of the invention.

[0095] Although this specification contains many specific implementation details, these should not be interpreted as limitations on the scope of any embodiment or of what may be claimed, but rather as descriptions of features that are specific to particular implementations of particular embodiments. Certain characteristics described in this specification in the context of different implementations may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented individually in multiple implementations or in any suitable subcombination. Furthermore, although the features described above may be described as functioning in certain combinations, and even initially claimed as such, in some cases one or more features from a claimed combination may be deleted from that combination, and a claimed combination may be directed to a subcombination or variation of a subcombination.

Claims

1. A controller for controlling operation of a hybrid vehicle, the hybrid vehicle comprising an engine, an aftertreatment system, and an energy storage device, the aftertreatment system comprising a selective catalytic reduction (SCR) catalyst coupled to the engine, the controller being configured to be operatively coupled to the engine, the energy storage device, and the aftertreatment system, the controller being configured to: estimating an exhaust gas temperature and an exhaust gas flow rate of exhaust gas received by the aftertreatment system from the engine based on a set of engine operating parameters; estimating an exhaust cooling rate of the SCR catalyst based on the estimated exhaust temperature and exhaust flow rate and the SCR catalyst temperature; determining an ambient cooling rate of the SCR catalyst based on an ambient temperature of an environment external to the aftertreatment system, a vehicle speed of the hybrid vehicle, and an SCR catalyst temperature; The SCR catalyst temperature change rate is estimated based on the exhaust gas cooling rate and the ambient cooling rate, wherein The SCR catalyst temperature change rate is the change of the SCR catalyst temperature over time; and A load distribution between the engine and the energy storage device is adjusted based on the rate of change of the SCR catalyst temperature.

2. The controller according to claim 1, further configured to: In response to determining that the SCR catalyst temperature is greater than a low temperature threshold and is decreasing based on the SCR catalyst temperature rate of change, the load distribution is adjusted to increase the load on the engine.

3. The controller according to claim 1, further configured to: In response to determining that the SCR catalyst temperature is less than a high temperature threshold and is increasing based on the SCR catalyst temperature rate of change, the load distribution is adjusted to reduce the load on the engine.

4. The controller according to claim 1, further configured to: In response to determining that the increase in the rate of change of the SCR catalyst temperature is greater than a rate increase threshold, a load on the energy storage device is increased relative to the engine to reduce the rate of change of the SCR catalyst temperature.

5. The controller according to any one of claims 1 to 4, wherein: The set of engine operating parameters includes a speed of the engine, a torque demand from the engine, and a coolant temperature of a coolant flowing through the engine.

6. The controller according to any one of claims 1 to 4, wherein: The post-treatment system further includes an oxidation catalyst disposed upstream of the SCR catalyst; and The controller is configured to estimate the exhaust cooling rate further based on an oxidation catalyst temperature of the oxidation catalyst.

7. The controller according to any one of claims 1 to 4, further configured to: A reductant injection assembly is instructed to adjust an amount of reductant injected into the aftertreatment system.

8. The controller according to any one of claims 1 to 4, further configured to: In response to determining that the SCR catalyst temperature is within an optimal operating range, the load profile is adjusted based on load demand, desired fuel economy, an amount of remaining fuel, and / or an amount of remaining electricity in the energy storage device.

9. A hybrid vehicle comprising: engine; Energy storage devices; an aftertreatment system fluidly coupled to the engine and configured to receive exhaust generated by the engine, the aftertreatment system including a selective catalytic reduction (SCR) catalyst configured to treat a component of the exhaust; and a controller operably coupled to the engine, the energy storage device, and the aftertreatment system, the controller configured to: estimating an exhaust gas temperature and an exhaust gas flow rate of the exhaust gas based on a set of engine operating parameters, estimating an exhaust gas cooling rate of the SCR catalyst based on the estimated exhaust gas temperature and exhaust gas flow rate and the SCR catalyst temperature, determining an ambient cooling rate for the SCR catalyst based on an ambient temperature of an environment external to the aftertreatment system, a vehicle speed of the hybrid vehicle, and a temperature of the SCR catalyst, estimating an SCR catalyst temperature change rate based on the exhaust gas cooling rate and the ambient cooling rate, wherein the SCR catalyst temperature change rate is a change in SCR catalyst temperature over time, and A load distribution between the engine and the energy storage device is adjusted based on the rate of change of the SCR catalyst temperature.

10. The hybrid vehicle according to claim 9, wherein: The controller is configured to: In response to determining that the SCR catalyst temperature is greater than a low temperature threshold and is decreasing based on the SCR catalyst temperature rate of change, the load distribution is adjusted to increase the load on the engine.

11. The hybrid vehicle according to claim 9, wherein: The controller is configured to: In response to determining that the SCR catalyst temperature is less than a high temperature threshold and is increasing based on the SCR catalyst temperature rate of change, the load distribution is adjusted to reduce the load on the engine.

12. The hybrid vehicle according to claim 9, wherein: The controller is configured to: In response to determining that the increase in the rate of change of the SCR catalyst temperature is greater than a rate increase threshold, a load on the energy storage device is increased relative to the engine to reduce the rate of change of the SCR catalyst temperature.

13. The hybrid vehicle according to any one of claims 9 to 12, wherein: The set of engine operating parameters includes a speed of the engine, a torque demand from the engine, and a coolant temperature of a coolant flowing through the engine.

14. The hybrid vehicle according to any one of claims 9 to 12, wherein: The post-treatment system further includes an oxidation catalyst disposed upstream of the SCR catalyst; and The controller is configured to estimate the exhaust cooling rate further based on an oxidation catalyst temperature of the oxidation catalyst.

15. The hybrid vehicle according to any one of claims 9 to 12, wherein: The aftertreatment system includes a reductant injection assembly configured to inject a reductant into the aftertreatment system; and The controller is further configured to: The reductant injection assembly is instructed to adjust an amount of reductant injected into the aftertreatment system.

16. The hybrid vehicle according to any one of claims 9 to 12, wherein: The controller is further configured to: In response to determining that the SCR catalyst temperature is within an optimal operating range, the load profile is adjusted based on load demand, desired fuel economy, an amount of remaining fuel, and / or an amount of remaining electricity in the energy storage device.

17. A method for controlling operation of a hybrid vehicle, the hybrid vehicle comprising an engine, an aftertreatment system, and an energy storage device, the aftertreatment system comprising a selective catalytic reduction (SCR) catalyst coupled to the engine, the method comprising: estimating, by a controller of the hybrid vehicle, an exhaust gas temperature and an exhaust gas flow rate of exhaust gas received by the aftertreatment system from the engine based on a set of engine operating parameters; estimating, by the controller, an exhaust gas cooling rate of the SCR catalyst based on the estimated exhaust gas temperature, the exhaust gas flow rate, and the SCR catalyst temperature; determining, by the controller, an ambient cooling rate of the SCR catalyst based on an ambient temperature of an environment external to the aftertreatment system, a vehicle speed of the hybrid vehicle, and a temperature of the SCR catalyst; estimating, by the controller, an SCR catalyst temperature change rate based on the exhaust gas cooling rate and the ambient cooling rate, wherein the SCR catalyst temperature change rate is a change in SCR catalyst temperature over time; and The controller adjusts load distribution between the engine and the energy storage device based on the rate of change of the SCR catalyst temperature.

18. The method according to claim 17, further comprising: In response to a determination by the controller that the SCR catalyst temperature is greater than a low temperature threshold and is decreasing based on the SCR catalyst temperature rate of change, the load profile is adjusted by the controller to increase the load on the engine.

19. The method according to claim 17 or 18, further comprising: In response to a determination by the controller that the SCR catalyst temperature is less than a high temperature threshold and is increasing based on the SCR catalyst temperature rate of change, the load profile is adjusted by the controller to reduce the load on the engine.

20. A controller for controlling operation of a hybrid vehicle, the hybrid vehicle comprising an engine, an aftertreatment system, and an energy storage device, the aftertreatment system comprising a selective catalytic reduction (SCR) catalyst coupled to the engine, the controller being configured to be operatively coupled to the engine, the energy storage device, and the aftertreatment system, the controller being configured to: estimating an exhaust gas cooling rate of the SCR catalyst; determining or estimating an ambient cooling rate of the SCR catalyst; The SCR catalyst temperature change rate is estimated based on the exhaust gas cooling rate and the ambient cooling rate, wherein: The SCR catalyst temperature change rate is the change of the SCR catalyst temperature over time; and A load distribution between the engine and the energy storage device is adjusted based on the rate of change of the SCR catalyst temperature.

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