Engine system with exhaust injection after three-way catalytic converter

Abstract

The invention relates to an engine system. When exhaust gas temperatures are above 500 degrees Celsius, the engine system uses a three-way catalyst under various load conditions, then injects air and mixes to convert all hydrocarbons and carbon monoxide. A three-way catalytic converter is disposed in the exhaust system. A nozzle is configured to inject air into the exhaust system downstream of the three-way catalytic converter. A mixing plate with or without a catalyst coating is disposed in the exhaust system downstream of the nozzle. The mixing plate is arcuate with a concave side facing the nozzle to improve carbon monoxide conversion. Downstream of the mixing plate, an optional two-way catalytic converter is added to further reduce exhaust pipe hydrocarbon and carbon monoxide emissions.

Description

Technical Field

[0001] This invention relates to engine systems and exhaust systems thereof, and more particularly, to engine systems with exhaust systems that employ air injection followed by enhanced mixing, all located downstream of a three-way catalytic converter system to convert residual carbon monoxide, including under heavy-duty vehicle load conditions with enrichment operation. Background Technology

[0002] Internal combustion engines convert fuel and air into various compounds while extracting energy to perform their intended functions, such as propelling a vehicle. The compounds emitted from the engine can be further converted or treated by various aftertreatment systems. Three-way catalytic converters are designed to convert hydrocarbons, carbon monoxide, and nitrogen oxides into harmless elements or compounds. Three-way catalytic converters work most efficiently when the engine is running with a stoichiometric air-fuel mixture to achieve optimal conversion efficiency. Some engines, such as gasoline engines, can operate under non-stoichiometric conditions for various purposes. For example, when operating under heavy loads, the engine can operate under conditions richer than stoichiometric, such as for diagnostic or component protection purposes, or under heavy loads that generate excessive heat. For various reasons, it may be undesirable to release non-stoichiometric combustion products from the engine into the atmosphere.

[0003] Furthermore, some regulations may require assessments of vehicle engine operation under heavy-load conditions, such as maximum vehicle payload and traction capacity. Operating under these conditions while simultaneously providing optimal diagnostics and component protection is challenging, but also desirable.

[0004] Therefore, it is desirable to provide a vehicle exhaust aftertreatment system that can provide the necessary diagnostic and component protection purposes while limiting unwanted emissions or emissions exceeding regulatory requirements. Furthermore, other desirable features and characteristics of the invention will become apparent from the following detailed description and the appended technical solutions, taken in conjunction with the accompanying drawings and the foregoing technical and background information. Summary of the Invention

[0005] The engine system uses a three-way catalytic converter, then injects and mixes air to convert all hydrocarbons and carbon monoxide into harmless components under varying load conditions. In various embodiments, the engine system includes an engine configured to consume fuel and air to produce an exhaust stream. An exhaust system directs the exhaust stream from the engine to an exhaust pipe for emission. A three-way catalytic converter is disposed in the exhaust system. Nozzles are configured to inject air into the exhaust system downstream of the three-way catalytic converter. A mixing plate is disposed in the exhaust system downstream of the nozzles. The mixing plate is arc-shaped with a concave side facing the nozzles to improve carbon monoxide conversion.

[0006] In other embodiments, the oxidation chamber is located downstream of the catalytic converter, and the mixing plate is located within the oxidation chamber.

[0007] In other embodiments, multiple holes are formed through the mixing plate and distributed on the mixing plate. The mixing plate has an outer perimeter and a series of cutouts around the outer perimeter.

[0008] In other embodiments, a substrate chamber is located downstream of the mixing plate. The substrate chamber contains a substrate configured to guide and mix exhaust streams.

[0009] In other embodiments, at least one of the mixing plate and the substrate is coated with a catalyst to enhance the reduction of carbon monoxide in the exhaust stream.

[0010] In other embodiments, the controller is configured to control the rate of air ejected through the nozzle based on the engine load.

[0011] In other embodiments, the catalytic converter includes a pair of three-way catalytic converters configured to convert hydrocarbons, carbon monoxide, and nitrogen oxides.

[0012] In other embodiments, the injection system includes a nozzle and a pump configured to pressurize air from the engine and supply air to the nozzle.

[0013] In other embodiments, the pump includes the engine's turbocharger.

[0014] In other embodiments, the exhaust valve of the turbocharger includes a three-way valve configured to direct boost air to the nozzle.

[0015] In many other embodiments, the engine system includes an engine configured to consume fuel and air to produce an exhaust stream. An exhaust system directs the exhaust stream from the engine to an exhaust pipe for emission. Two three-way catalytic converters are disposed in the exhaust system. An air injection system with nozzles is configured to inject air into the exhaust system downstream of the three-way catalytic converters. A mixing plate is disposed in the exhaust system downstream of the nozzles. The mixing plate is arc-shaped and has a concave side facing the nozzles.

[0016] In other embodiments, the oxidation chamber is located downstream of the three-way catalytic converter. A mixing plate is disposed within the oxidation chamber. The oxidation chamber has heat-insulating walls to retain heat.

[0017] In other embodiments, a plurality of holes are formed through and distributed on the mixing plate. The mixing plate has an outer periphery and a series of cutouts around the outer periphery. The nozzle is formed by a pipe segment extending into the exhaust system, wherein the pipe segment has a nozzle orifice comprising an opening in the pipe segment that faces the mixing plate in a downstream direction.

[0018] In other embodiments, a substrate chamber is located downstream of the mixing plate. The substrate chamber contains a substrate configured to guide and mix the exhaust stream. The substrate is coated with a binary catalyst configured to convert hydrocarbons and carbon monoxide.

[0019] In other embodiments, the pump supplies air to a buffer tank, which receives and stores the air from the pump. The buffer tank can control the air jet flow while reducing the pump's flow requirements.

[0020] In other embodiments, the sensor is configured to measure parameters of the exhaust gas. The sensor is positioned in the exhaust system downstream of the nozzle. The controller is configured to control the rate of air injected through the nozzle based on these parameters, such that the rate corresponds to the parameters measured by the sensor, thereby consuming all remaining carbon monoxide in the exhaust stream.

[0021] In other embodiments, the engine includes a crankcase connected to an air injection system. Crankcase energy from the crankcase is configured to introduce air into the nozzles.

[0022] In other embodiments, the injection system includes a pump configured to pressurize air from the engine and supply air to the nozzles. A heater is disposed in the injection system and configured to heat the pressurized air.

[0023] In other embodiments, the pump includes a turbocharger for the engine. The exhaust valve of the turbocharger includes a three-way valve configured to divert boost air to the nozzle.

[0024] In several other embodiments, the engine is configured to consume gasoline fuel and air to produce an exhaust stream. An exhaust system directs the exhaust stream from the engine to an exhaust pipe for emission. The exhaust system includes two three-way catalytic converters. An oxidation chamber is located downstream of the second three-way catalytic converter in the exhaust system. An air injection system with nozzles injects air into the exhaust system for mixing with the exhaust stream in the oxidation chamber. A mixing plate is located downstream of the nozzle in the oxidation chamber. The mixing plate is arc-shaped and has a concave side facing the nozzle. The engine is configured to operate under stoichiometric conditions, producing excess carbon monoxide to saturate the three-way catalytic converter. The oxidation chamber is configured to convert the excess carbon monoxide into carbon dioxide. Attached Figure Description

[0025] Exemplary embodiments will now be described in conjunction with the following accompanying drawings, wherein the same reference numerals denote the same elements, in which:

[0026] Figure 1 This is a schematic diagram of an engine system with rear three-way catalytic converter air injection and mixing features according to various embodiments;

[0027] Figure 2This is a schematic diagram of an engine system having a rear three-way catalytic converter air injection, mixing features and a substrate system according to various embodiments;

[0028] Figure 3 This is a schematic diagram of an engine system with rear three-way catalytic converter air injection, mixing features and a rear three-way catalytic converter sensor according to various embodiments;

[0029] Figure 4 This is a schematic diagram of an engine system with post-three-way catalytic converter air injection and pipe-based mixing features according to various embodiments;

[0030] Figure 5 This is a schematic diagram of an engine system with post-three-way catalytic converter air injection and mixing characteristics from a turbine exhaust gas source, according to various embodiments.

[0031] Figure 6 According to various embodiments, for Figure 1-5 A cross-sectional view of the hybrid plate arrangement of the system;

[0032] Figure 7 It is based on the overall path of each embodiment. Figure 6 The cross-sectional view taken by line 7-7 in the figure shows the mixing plate; and

[0033] Figure 8 It is an airflow control diagram with a buffer tank and an optional small-range air pump according to various embodiments. Detailed Implementation

[0034] The following detailed description is exemplary in nature and is not intended to limit application or use. Furthermore, there is no intention to be bound by any express or implied theory presented in the preceding technical field, background, brief overview, or the following detailed description.

[0035] As described herein, injecting air after a three-way catalytic converter exhaust treatment reduces emissions of exhaust gases such as hydrocarbons, carbon monoxide, and particulate matter (soot). At exhaust temperatures above 500 degrees Celsius, hydrocarbons, carbon monoxide, and particulate matter are rapidly converted by introducing air into the exhaust stream. This conversion is assisted by a mixing device that generates turbulence to increase the mixing and reaction of the air and exhaust. In embodiments, a mixing plate and heat-insulated exhaust pipe after air injection further enhance the oxidation of the gases (hydrocarbons and carbon monoxide). The mixing plate may be coated with a catalyst to improve conversion rates, particularly carbon monoxide conversion. The air injection source may be provided by an auxiliary pump or drawn from the engine compressor via valves and / or choke nozzles. For vehicles with turbochargers, boost pressure and turbocharged air can be used as the source. In other embodiments, the air source may be from the crankcase, using energy generated in the crankcase to provide air injection. In embodiments, the air source may be a turbocharger compressor included in the engine or another air pumping device. The aftertreatment system configuration typically consists of a three-way catalytic converter, an air injection system, and an arc-shaped mixing plate. An optional two-way catalytic converter can be added to further reduce exhaust emissions of hydrocarbons and carbon monoxide. In this embodiment, hydrocarbons are converted into harmless carbon dioxide and water, and carbon monoxide is converted into harmless carbon dioxide.

[0036] See Figure 1 Engine system 20 includes an internal combustion engine 22, which in this embodiment is an engine that consumes gasoline and air. Engine 22 may be naturally aspirated or may include a turbocharger or supercharger to pump air into the engine for combustion. Engine system 20 includes an exhaust system 24 for delivering exhaust gas from the combustion chamber of engine 22 to an exhaust pipe 26 for emission into the atmosphere. A duct 28 extends from engine 22, for example from its exhaust manifold to an aftertreatment device in the form of a three-way catalytic converter 30. A second three-way catalytic converter 32 is disposed downstream of the three-way catalytic converter 30, and an open chamber 34 is provided between the two three-way catalytic converters 30, 32. The three-way catalytic converters 30, 32 are configured to convert three components in the gas stream into other elements or compounds, including converting hydrocarbons, carbon monoxide, and nitrogen oxides into harmless elements or compounds. The three-way catalytic converters 30, 32 may contain a catalyst, such as platinum, palladium, rhodium, or other materials.

[0037] Oxygen sensor 36 is positioned upstream of the three-way catalytic converter 30 in pipe 28 to measure the oxygen content in the airflow leaving engine 22. Another oxygen sensor 38 is positioned downstream of the three-way catalytic converter 30 in chamber 34. Oxygen sensor 36 measures engine emissions, specifically the carbon monoxide content in the airflow leaving engine 22. Oxygen sensor 38 measures the oxygen content in the airflow after the three-way catalytic converter 30 and can be used to determine the amount of residual carbon monoxide in chamber 34.

[0038] Engine 22 typically has an engine block 40 that defines a plurality of cylinders, such as cylinder 42, each cylinder having a piston, such as piston 44, which is coupled to a crankshaft (not shown) for reciprocating motion within its cylinder 42. In the present embodiment, eight cylinders are included. In other embodiments, a different number of cylinders may be included. In each cylinder, such as cylinder 42, a combustion chamber, such as combustion chamber 46, is defined. A fuel and air mixture (not shown) is delivered to combustion chamber 46 and ignited, causing thermal expansion of the exhaust gas, which in turn causes reciprocating motion of piston 44 and the like. Combustion intake air is supplied via intake system 48. Intake air may be distributed to cylinders 42 and the like. Exhaust system 24 directs exhaust gas away from cylinders 42 and the like after combustion. Exhaust system 24 may include aftertreatment system 52, which includes three-way catalytic converters 30, 32.

[0039] Engine system 20 also includes a control system 54, which typically includes a controller 56, various actuators, and sensors. The controller 56 can receive various signals from the sensors and send control signals to the various actuators to operate engine system 20. Sensors are sensing devices that sense the observable state of engine system 20, and in the current embodiment include oxygen sensors 36, 38, and other typical engine system sensors. In the current embodiment, actuators may include exhaust valve 50, pump 60, and heater 62, as well as other typical engine system actuators. The controller 56 commands the amount of fuel delivered to each cylinder 42, etc. The commanded amount of fuel, given the current operating state of engine 22, is typically related to the amount required for stoichiometric operating conditions. Stoichiometric operating results in the complete combustion of fuel and air delivered to cylinders 42, etc.

[0040] Under certain operating conditions, the controller 56 may deviate from stoichiometric operating conditions based on a pre-programmed algorithm. For example, under heavy load conditions, excess fuel may be delivered to cylinders 42, etc., for various reasons. Other operating conditions may require excess fuel for diagnostic purposes. When excess fuel is delivered, the aftertreatment system 52 may become saturated, meaning that complete conversion of target components in the exhaust stream will not occur. For example, not all hydrocarbons and carbon monoxide will be converted as expected. Furthermore, under heavy load conditions, particulate matter may remain in the exhaust stream. Therefore, additional measures are described herein to address hydrocarbons, carbon monoxide, and particulate matter remaining in the exhaust stream under non-stoichiometric and / or other conditions.

[0041] Figure 1 The current embodiment includes an oxidation chamber 66 that receives exhaust gas exiting the three-way catalytic converter 32 and is disposed downstream therefrom. The oxidation chamber 66 has a heat-insulating wall 68 configured to retain heat within the oxidation chamber 66. For example, the wall 68 may be a double-layered metal with air in between, or a heat-insulating material such as ceramic may be disposed on a single metal layer or between two metal layers. A mixing plate 70 is disposed within the oxidation chamber 66 and spans the flow path through the oxidation chamber 66 to maximize the interaction and mixing of the air and exhaust flow. An injection nozzle 72 is disposed in the oxidation chamber 66 upstream of the mixing plate 70. In this example, the injection nozzle 72 is located at the centerline 74 of the oxidation chamber 66. The injection nozzle 72 is part of an injection system 76, which includes a duct circuit 78, a pump 60, a heater 62, and a control valve 80. The control valve 80 is configured to control the airflow through the duct circuit 78 and may be part of an actuator of the engine system 20.

[0042] In the current embodiment, the injection system 76 delivers fresh air from the intake system 48 of the engine 22 upstream of the cylinder 42, etc., to the nozzle 72 within the oxidation chamber 66. It should be noted that the air may also originate from the crankcase 82, the compressor of the engine 22, or another pumping device of the engine 22. With the crankcase 82 as the source, crankcase energy can be used to flow air through the nozzle 72, or the pump 60 can be added to increase the injection pressure. The pump 60 can be any type of pump, including a diaphragm pump, and the heater 62 can be any type of heater capable of raising the air temperature to 500 degrees Celsius or higher, such as an electric element heater or an exhaust heat exchanger. The injection system 76 is configured to inject hot (500 degrees Celsius or higher) air into the oxidation chamber 66. When the injected air mixes with the exhaust flow, with the aid of the mixing plate 70, residual hydrocarbons, carbon monoxide, and particulate matter are consumed / converted into harmless elements or compounds. Based on inputs from various sensors, including sensors 36 and 38, the amount of jet air is supplied to be sufficient to consume the amount of remaining components determined by controller 56.

[0043] A mixing plate 70 is disposed in the oxidation chamber 66, downstream of the nozzle 72, so that the injected air impacts the mixing plate 70 and disrupts the laminar flow of the exhaust. Under the heavy load of the engine 22, the exhaust flow rate is high, and therefore the flow is laminar in nature. The mixing plate 70 has an arcuate shape, which can be described as curved, with a concave side 84 facing the nozzle 72. The mixing plate 70 has multiple holes and / or gaps, such as holes and / or gaps through its body and around its outer periphery, to allow the ongoing exhaust flow, which will be described in more detail below. The mixing plate 70 may be made of ordinary steel or may have a binary catalyst coating 92 applied to its surface, such as platinum, palladium, etc., to aid in the conversion / oxidation of residual carbon monoxide and hydrocarbons. The exhaust with mixed air in the oxidation chamber 66 consumes the residual / residual carbon monoxide, hydrocarbons, and / or particulate matter, and the exhaust is delivered to the exhaust pipe 26 and discharged at 86.

[0044] The amount of air injected by the injection system 76 can be correlated with the load on the engine 22. For example, as the load on the engine 22 increases, the amount of air injected increases. The pump 60 overcomes the exhaust pressure in the oxidation chamber 66 to ensure flow through the nozzle 72. In some embodiments, the heater 62 can be omitted when the exhaust temperature is sufficiently high (above 500 degrees Celsius). In any case, the exhaust valve 50 can be adjusted to ensure a sufficient temperature in the oxidation chamber 66.

[0045] See Figure 2 The engine system 20 shown is... Figure 1 The modified system includes an additional substrate chamber 88 between the oxidation chamber 66 and the exhaust pipe 26. The substrate chamber 88 contains a substrate 90, such as a high-porosity, honeycomb, or other multi-channel substrate 90. Adding a high-porosity converter substrate 90, such as an uncoated ceramic material, further increases the combustion rate of hydrocarbons, carbon monoxide, and particulate matter by increasing the mixing and reaction temperature, thereby further reducing emissions from the engine system 20 and helping to maintain exhaust heat in the substrate 90. A copper oxide(i) or rare earth metal oxide coating 92 may be added to the substrate 90 to prevent catalyst poisoning, and small amounts of precious metals such as platinum and palladium may be added to the oxidation chamber 66 and / or the substrate chamber 88, while reducing their amount in the three-way catalytic converters 30, 32. This addition further improves the consumption of hydrocarbons, carbon monoxide, and particulate matter under low-load conditions, such as after a cold start of the engine 22. Heating the air supply, for example through heater 62 and / or by using exhaust energy from engine 22, increases air injection energy to enhance air-exhaust mixing and improve conversion under cold conditions. Adding catalyst to mixing plate 70 and / or substrate 88, for example via wash application, improves oxidation and reduces emissions.

[0046] See Figure 3 The engine system 20 shown is... Figure 1 and Figure 2 The engine system modification involves adding an additional conduit 94 between the three-way catalytic converter 32 and the oxidation chamber 66. The nozzle 72 moves into the conduit 94 to inject air into it, while the mixing plate 70 remains in the oxidation chamber 66. An additional sensor 96 is added to the conduit 94 downstream of the nozzle 72. The air injection conduit 94, which then enters the downstream oxidation chamber 66, provides an opportunity to better sense the oxygen / temperature level of the exhaust flow before it enters the oxidation chamber 66. Furthermore, the injection conduit 94 can result in enhanced mixing as the flow passes through the narrower conduit 94 and then into the larger oxidation chamber 66. The sensor 96 can be an oxygen sensor or a temperature sensor. Whether configured to monitor oxygen or temperature, the sensor 96 is used by the controller 56 to determine the air injection rate through the nozzle 72 and, in either case, correlates the air injection rate with the load on the engine 22. The three-way catalytic converters 30, 32 and the two-way catalytic converter (oxidation chamber 66 and substrate chamber 88) have separate packages separated by the conduit 94. Similarly, when needed, they can be constructed individually and / or obtained from different suppliers and assembled via the connection of pipe 94.

[0047] The addition of sensor 96 enhances the control over air injection quantity and timing, and can be used to provide a signal / basis for functional diagnostics of the air injection system. Controller 56 can operate with feedforward and / or feedback control schemes. The feedforward method receives input from various sensors and calculates the air injection rate based on flow rate (engine load) and oxygen content in the exhaust as a prediction of the required injected air flow, initiating pre-control to offset the anticipated demand. Based on the calculated injected air flow, the controller instructs pump 60 to supply sufficient air flow to convert the expected carbon monoxide and other components. Using feedback control, supplementary input from sensor 96 enables the air flow through nozzle 72 to be set at a rate that ensures consistency with the actual oxygen content / temperature measured by sensor 96. For example, when sensor 96 indicates a need for correction by deviating from the currently supplied air injection flow, the corrected air flow rate is discerned from the anticipated demand of the feedforward control, setting the rate effectively based on the measurement readings of sensor 96.

[0048] refer to Figure 4 The engine system 20 shown is... Figure 3 The engine system was modified by eliminating the oxidation chamber 66 and moving the mixing plate 70 into the pipe 94. The mixing plate 70 is physically similar to... Figure 1-3The mixing plates are smaller to fit within conduit 94. This arrangement results in a space-saving and economical structure, suitable for a more compact packaging environment, as oxidation chamber 66 is eliminated. Conversions that would otherwise occur in oxidation chamber 66 initially take place in conduit 94 and ultimately in substrate chamber 88. The inclusion of conduit 94 again means that the three-way catalytic converters 30, 32 and substrate chamber 88 are packaged separately, optimizing supply and manufacturing options.

[0049] like Figure 5 As shown, one version of engine system 20 is illustrated for use with engine 22, including turbocharger 100. Turbocharger 100 can be used as a source of compressed air to supply to nozzles 72 via injection system 76. In the current embodiment, turbocharger 100 includes exhaust valve 102 configured as a three-way valve to supply excess boosted air directly into the intake manifold or to nozzles 72 via injection system 76. Exhaust valve 102 can divert some or all of the available boosted air to injection system 76. Under heavy loads, exhaust temperatures are typically high enough that additional heaters are not required to reach levels exceeding 500 degrees Celsius. The current embodiment enables the exhaust driving turbocharger 100 to be diverted through exhaust valve 102 and injection system 76 and into oxidation chamber 66. This reduces boost pressure and eliminates the need for an additional pump, as turbocharger 100 provides the flow. Exhaust valve 102 utilizes exhaust energy to increase intake pressure, reduce catalyst temperature in the three-way catalytic converters 30 and 32, and improve traction at low speeds. Exhaust valve 50 can be adjusted to close to increase exhaust temperature at idle and low load, thereby improving engine low-speed and load emission performance. Throttling nozzles at valve 80 or nozzle 72 can be used to control the air injection rate at low cost based on boost pressure. The air injection rate is related to the exhaust temperature after the three-way catalytic converters 30 and 32, as well as the levels of hydrocarbons, carbon monoxide, and particulate matter.

[0050] Figure 6 An embodiment of the mixing plate 70 is shown. In this embodiment, the injection nozzle 72 is disposed in the conduit 94, and the mixing plate 70 is disposed in the oxidation chamber 66. The nozzle 72 includes a conduit section 104 of the injection system 76, which in this example extends laterally into the conduit 94, or in other embodiments, extends laterally into the oxidation chamber 66. The nozzle orifice 106 is an opening in the conduit section 104 that injects air in a downstream direction 108. The end 109 of the conduit section 104 is closed, such that all fluid flowing from the nozzle 72 passes through the nozzle orifice 106. In the current embodiment, the nozzle orifice 106 cuts through the conduit section 104 at an angle 110 of 30 degrees. The angle 110 helps to diffuse the injected air into the exhaust flow 112. The nozzle orifice 106 is located at the center of the centerline 74 of the conduit 94 and the oxidation chamber 66.

[0051] The mixing plate 70 is formed as an arc-shaped metal plate, bending downstream at the centerline 74, opposite its outer periphery 116 at the wall 68 of the oxidation chamber 66. See also... Figure 7 The mixing plate 70 includes a plurality of spaced-apart holes 118 distributed throughout the mixing plate 70. The holes 118 may be arranged in rows and columns as shown, or may be distributed in another pattern to allow flow through the mixing plate 70. The holes 118 can be used to enhance combustion, for example, as described above, by adding a catalyst coating to the mixing plate 70 to further enhance combustion. The holes 118 are formed parallel to the centerline 74 through the mixing plate 70. Furthermore, the mixing plate 70 has four cuts 121-124 around its outer periphery. The cuts 121-124 provide four openings 125-128 much larger than the holes 118, ensuring sufficient exhaust flow. The cuts 121-124 are evenly spaced around the 360° periphery 116 of the mixing plate 70 and centered at 45°, 135°, 225°, and 315°. The cuts 121-124 are formed by arched edges, such as edge 130, between portions of the contact walls 68 of the outer periphery 116. The mixing plate 70 enhances mixing by generating reverse turbulence. The air injector's injection angle of 110° simulates the curved shape of the mixing plate 70 to enhance the mixing of air and exhaust gas. For example, by using commercial fluid dynamics simulation software, detailed dimensions of the mixing plate 70 are calculated for each application to ensure sufficient flow rate, acceptable back pressure, and optimal mixing.

[0052] Figure 8 An example airflow control system 140 with a buffer tank 142 and a small-flow-range air pump 144 is shown. Air is delivered from the air pump 144 to the buffer tank 142 via a conduit line 146 and a check valve 148. The check valve 148 allows unidirectional flow through the conduit line 146 into the buffer tank 142 for storage and selective delivery to the nozzle 72. Air is delivered to the nozzle 72 in the exhaust system 24 via a conduit line 150 and a one-way check valve 152, which restricts the flow in one direction, i.e., toward the nozzle 72. The conduit line 150 also includes a mass flow control valve 154 having an actuator as a unit for controlling the jet air flow toward the nozzle 72.

[0053] Air pump 144 is operated by pump controller 156. Pump controller 156 is coupled to pressure sensor 158 at buffer tank 142. Pump controller 156 may also be coupled to controller 56 for cross-communication. In other embodiments, different numbers of controllers 156, 56 may be used, such as a single controller. Buffer tank 142 also includes a pressure reducing valve 160 to limit the pressure to the maximum rated value of buffer tank 142.

[0054] Air pump 144, activated by pump controller 156, supplies air to air buffer tank 142 to maintain a constant pressure (e.g., 5 bar). When the target pressure, determined by a reading from pressure sensor 158, is reached in buffer tank 142, pump controller 156 cyclically shuts off air pump 144. Based on the engine equivalence ratio and catalyst temperature, and according to a signal received from controller 56, mass flow control valve 154 is adjusted to open, and air is injected from buffer tank 142 into exhaust system 24 through nozzle 72. Mass air flow control valve 154 controls the injected air flow rate based on the actuator duty cycle frequency, which is directly related to the injected air flow rate. This embodiment enables the use of a smaller air pump 156 while meeting large transient air flow requirements through precise injection flow control.

[0055] Therefore, the engine system reduces exhaust gas (hydrocarbons and carbon monoxide) and particulate matter emissions without increasing the precious metal load on the three-way catalytic converter, including under enrichment engine operation. The system uses a three-way catalytic converter with downstream air injection directed to an arc-shaped mixing plate to increase the consumption of hydrocarbons, carbon monoxide, and particulate matter before atmospheric emission. In embodiments, a high-porosity substrate with / without a binary catalytic converter coating can be added downstream of the mixing plate exhaust configuration. The injected air is pressurized by an auxiliary pump or by an existing vehicle compressor / turbocharger to overcome exhaust pressures in the exhaust system, thereby controlling the air injection flow rate. A small amount of copper oxide(i) or a precious metal coating can be applied to the substrate or mixing plate while reducing the precious metal load in the three-way catalytic converter to save costs.

[0056] Although at least one exemplary embodiment has been presented in the foregoing detailed description, it should be understood that numerous variations exist. It should also be understood that the exemplary embodiments or exemplary models are merely examples and are not intended to limit the scope, applicability, or configuration of this disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient roadmap for implementing the exemplary embodiments or exemplary models. It should be understood that various changes can be made to the function and arrangement of the elements without departing from the scope of this disclosure as set forth in the appended disclosure and its legal equivalents.

Claims

1. An engine system, comprising: An engine configured to consume fuel and air to produce exhaust flow; An exhaust system configured to direct exhaust flow from the engine to the exhaust pipe for discharge; The catalytic converter in the exhaust system is configured to convert the components of the exhaust stream; A nozzle configured to inject air into the exhaust system downstream of the catalytic converter; A mixing plate, disposed in the exhaust system downstream of the nozzle, is arc-shaped and has a concave side facing the nozzle; and Oxygen sensors or temperature sensors are installed in the exhaust system; and The controller is configured as follows: Receives input from an oxygen sensor or a temperature sensor; Calculate the air injection rate based on the engine load and input; and Based on the calculated air injection rate, the air supply through the nozzle is ordered to be sufficient to convert the remaining components after the catalytic converter.

2. The engine system of claim 1, comprising an oxidation chamber disposed downstream of the catalytic converter, wherein a mixing plate and a nozzle are disposed in the oxidation chamber, the nozzle being positioned such that air is injected through holes in the mixing plate to impact the mixing plate.

3. The engine system of claim 1, wherein the mixing plate has a plurality of holes formed through the mixing plate and distributed on the mixing plate, and wherein the mixing plate has an outer periphery and a series of cuts around the outer periphery.

4. The engine system of claim 1, further comprising a base plate chamber disposed downstream of the mixing plate, wherein the base plate chamber includes a base plate configured to guide and mix exhaust streams.

5. The engine system of claim 4, wherein at least one of the mixing plate and the substrate is coated with a catalyst to enhance the reduction of carbon monoxide in the exhaust stream.

6. The engine system of claim 1, wherein an oxygen sensor or a temperature sensor is disposed between the nozzle and the mixing plate, and wherein the controller is configured to associate the air injection rate with the load on the engine using input from the oxygen sensor or the temperature sensor.

7. The engine system of claim 1, wherein the catalytic converter comprises a pair of three-way catalytic converters configured to convert hydrocarbons, carbon monoxide and nitrogen oxides.

8. The engine system of claim 1, further comprising an injection system including nozzles and a pump configured to pressurize air from the engine and supply air to the nozzles.

9. The engine system of claim 8, wherein the pump comprises a turbocharger of the engine.

10. The engine system of claim 9, comprising an exhaust valve for a turbocharger, wherein the exhaust valve includes a three-way valve configured to direct boost air to a nozzle.

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