WO2021194478A1

WO2021194478A1 - System for utilizing an exhaust gas recirculation jet pump

Info

Publication number: WO2021194478A1
Application number: PCT/US2020/024474
Authority: WO
Inventors: Jeffrey Michel MUDEK; Gregory Walter Sorge; Lorne Eugene Nix
Original assignee: Innio Waukesha Gas Engines Inc.
Priority date: 2020-03-24
Filing date: 2020-03-24
Publication date: 2021-09-30

Abstract

A system (10) is provided. The system (10) includes an internal combustion engine (12) including an intake manifold (50) and an exhaust manifold (52). The system (10) also includes an exhaust gas recirculation (EGR) system (14) coupled to the internal combustion engine (12) and configured to route exhaust gas generated by the internal combustion engine (12) from the exhaust manifold (52) to the intake manifold (50). The system (10) further includes at least one jet pump (36) disposed along an EGR circuit (40) of the EGR system (14), where the at least one jet pump (36) is configured to inject a high pressure energy fluid diverted from the EGR circuit (40) into the EGR circuit (40) and to provide a pumping effect to cause the exhaust gas to move along the EGR circuit (40).

Description

SYSTEM FOR UTILIZING AN EXHAUST GAS RECIRCULATION JET PUMP

BACKGROUND

[0001] The subject matter disclosed herein relates to internal combustion engines and, more particularly, to an exhaust gas recirculation jet pump (e.g., ejector) for use with an industrial internal combustion engine.

[0002] Exhaust gas recirculation (EGR) involves introduction of a portion of exhaust gases from an internal combustion engine back into a combustion chamber of the internal combustion engine, such as one or more cylinders of the internal combustion engine. EGR can be used to reduce formation of nitrogen oxides, such as, for example, nitrogen oxide (NO) and nitrogen dioxide (NO2) (referred to collectively hereinafter as NOx). The exhaust gas is substantially inert. Thus, introducing a portion of the exhaust gas into the combustion chamber of an internal combustion engine dilutes the mixture of fuel and air to be combusted, and resultantly lowers the peak combustion temperature and excess oxygen. As a result, the engine produces reduced amounts of NOx because NOx forms in higher concentrations at higher temperatures. Thus, EGR reduces or limits the amount of NOx generated during combustion of the engine. A pressure differential is utilized to move the exhaust gas in the EGR system. In particular, the intake pressure is lowered and the engine backpressure is increased to move the exhaust gas in the EGR system. However, this increase in engine backpressure affects (e.g., lowers) the engine efficiency.

BRIEF DESCRIPTION

[0003] Certain embodiments commensurate in scope with the originally claimed subj ect matter are summarized below. These embodiments are not intended to limit the scope of the claimed subject matter, but rather these embodiments are intended only to provide a brief summary of possible forms of the subject matter. Indeed, the subject matter may encompass a variety of forms that may be similar to or different from the embodiments set forth below.

[0004] In a first embodiment, a system is provided. The system includes an internal combustion engine including an intake manifold and an exhaust manifold. The system also includes an exhaust gas recirculation (EGR) system coupled to the internal combustion engine and configured to route exhaust gas generated by the internal combustion engine from the exhaust manifold to the intake manifold. The EGR system includes an EGR circuit, a turbocharger including a turbine and a compressor, an EGR cooler unit coupled to the turbocharger and the intake manifold, and an EGR valve configured to regulate an amount of the exhaust gas recirculated to the intake manifold of the internal combustion engine. The system further includes at least one jet pump disposed along the EGR circuit of the EGR system. The at least one jet pump is configured to inject a high pressure energy fluid into the EGR circuit and to provide a pumping effect to cause the exhaust gas to move along the EGR circuit.

[0005] In a second embodiment, an exhaust gas recirculation (EGR) system in combination with an internal combustion engine is provided. The system includes a low pressure EGR circuit. The system further includes at least one jet pump located in flow of the low pressure EGR circuit of the EGR system. The at least one jet pump is configured to inject a high pressure energy fluid into the low pressure EGR circuit and to provide a pumping effect to cause the exhaust gas from the internal combustion engine to move along the low pressure EGR circuit.

[0006] In a third embodiment, an exhaust gas recirculation (EGR) system in combination with an internal combustion engine is provided. The system includes a high pressure fuel source configured to provide a high pressure fuel to the internal combustion engine. The system also includes a high pressure EGR circuit. The system further includes at least one jet pump located in flow of the high pressure EGR circuit of the EGR system, wherein the at least one jet pump is connected in communication with the high pressure fuel source and is configured to inject the high pressure fuel into the high pressure EGR circuit and to provide a pumping effect to cause the exhaust gas from the internal combustion engine to move along the high pressure EGR circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] These and other features, aspects, and advantages of the present subject matter will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

[0008] FIG. 1 is a block diagram of an engine driven power generation system, in accordance with an embodiment;

[0009] FIG. 2 is a schematic diagram of an engine control module (ECM) for use in the engine driven power generation system, in accordance with an embodiment;

[0010] FIG. 3 is a schematic diagram of a jet pump utilized to inject a high pressure energy fluid into an EGR circuit, in accordance with an embodiment;

[0011] FIG. 4 is a schematic diagram of the engine driven power generation system of FIG. 1 utilizing a low pressure loop EGR system having one or more jet pumps, in accordance with an embodiment;

[0012] FIG. 5 is a schematic diagram of the engine driven power generation system of FIG. 1 utilizing a low pressure loop EGR system having one or more jet pumps (with alternative injection locations), in accordance with an embodiment; and

[0013] FIG. 6 is a schematic diagram of the engine driven power generation system of FIG. 1 utilizing a high pressure loop EGR system having a jet pump, in accordance with an embodiment. DETAILED DESCRIPTION

[0014] One or more specific embodiments of the present subject matter will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers’ specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

[0015] When introducing elements of various embodiments of the present subject matter, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0016] Embodiments of the present disclosure enable a high pressure energy fluid to be injected via one or more jet pumps (e.g., ejectors such as gas-gas ejectors) at one or more locations along an exhaust gas recirculation (EGR) circuit of an EGR system, which provides a pumping effect, to cause exhaust gas to move along the EGR circuit. The EGR system is coupled to an industrial internal combustion engine (e.g., having an intake manifold or intake system and an exhaust manifold or exhaust system). The EGR system includes the EGR circuit, a turbocharger (e.g., having a turbine and a compressor), an EGR cooler unit, and an EGR valve. In certain embodiments (e.g., in a low pressure loop EGR system), the high pressure energy fluid (e.g., compressor bypass valve discharge, wastegate valve discharge, intercooler discharge, etc.) is injected between the turbine of the turbocharger and an inlet of the EGR cooler unit and/or between an outlet of the EGR cooler unit and the EGR valve. In certain embodiments (e.g., in a low pressure loop EGR system), one or more sources (e.g., compressor bypass valve discharge fluid, wastegate valve discharge fluid, intercooler discharge fluid, etc.) are located between the exhaust manifold and the turbine of the turbocharger, between the compressor of the turbocharger and the intercooler, and/or between the intercooler and the intake manifold. In certain embodiments (e.g., in a high pressure loop EGR system), a source for the high pressure energy fluid includes a high pressure (“blow-through”) fuel supply system (e.g., where a fuel supply pressure is greater than a boost pressure produced by the compressor of the turbocharger). In these embodiments, the injection point for high pressure energy fluid (e.g., gaseous fuel) may be the intake manifold (e.g., before the throttle). Utilization of the high pressure energy fluid (e.g., sometimes from high pressure energy sources such as compressor bypass valve discharge fluid, wastegate valve discharge fluid, intercooler discharge fluid, fuel, etc.), in conjunction with the one or more jet pumps disposed along or in flow of the EGR circuit, to drive the circulation of the exhaust gas or EGR flow in the EGR circuit minimizes or avoids the need for increasing the engine backpressure (i.e., the exhaust gas pressure that is produced by the engine to overcome the hydraulic resistance of the exhaust system to discharge gases into the atmosphere), thus, improving the efficiency of the engine. In addition, the injection of the high pressure energy fluid may be utilized during full speed and load conditions as well as during transient events. Further, the injection of the high pressure energy fluid utilizing the one or more jet pumps promotes the EGR flow with zero moving parts, thus, providing a robust mechanical solution.

[0017] One example of an engine driven power generation system 10 is illustrated in FIG. 1. It should be noted that the engine generates and outputs the power, but the application of the power may be for electrical power generation, gas compression, mechanical drive, cogeneration (e.g., combined heat and power), trigeneration (e.g., combined heat, power, and industrial chemicals for greenhouse applications), or other applications. The system includes an engine 12 (e.g., reciprocating internal combustion engine) coupled to an exhaust gas recirculation (EGR) system 14 The system 10 is adapted for utilization in stationary application (e.g., industrial power generating engines or stationary reciprocating internal combustion engines). Although in certain embodiments, the techniques described may be utilized in mobile applications (e.g., marine or locomotive). In certain embodiments, the system 10 may generate power greater than 2 megawatts (MW). In other embodiments, the system 10 may generate less than 2 MW of power (e.g., between 1 MW and 2 MW of power, or even less than 1 MW of power). The system 10 may also operate the engine 12 at a stoichiometric air fuel equivalence ratio (e.g., l = 1) while utilizing EGR as a diluent. Operating the engine 12 under stoichiometric conditions enable an exhaust aftertreatment system (e.g., 3-way catalyst) to be utilized by the system 10 to reduce emissions. It should be noted that the lambda set-point may be rich (e.g., l is less than 1.0), in some modes of operation. The major determiner for the actual l is dictated by emissions output, commonly referred to as “stack-out”, from the exhaust aftertreatment system. In certain embodiments, operation may target a specific l value or dither within a l range, at a specific frequency, to achieve the desired “stack out” emissions. It is typical to operate stoichiometric/rich burn-engines with l of 0.96 to 1.04, but this is mainly determined by the specific exhaust aftertreatment system (e.g., precious metal loadings, coatings, temperature, etc.). Variations in l have dynamic implications on the EGR system 14 that are accounted for by the ECM 16. In certain embodiments, the system 10 may also operate the engine under lean burn conditions while also utilizing the EGR as a diluent and an exhaust aftertreatment system (e.g., two-way oxidation catalytic converters ("Oxi-Cat") and/or Selective Catalytic Reduction (SCR) actively injecting a reductant into the catalyst (such as, but not necessarily limited to, ammonia or urea)).

[0018] As described in greater detail below, a high pressure energy fluid may be injected via one or more jet pumps 36 (e.g., ejectors such as gas-gas ejectors) at one or more locations along an EGR circuit 40 (see FIGS. 4-6) of an EGR system 14, which provides a pumping effect, to cause exhaust gas to move along the EGR circuit 40. The EGR system 14 may utilize a high pressure loop EGR system 14 (e.g., exhaust gas is diverted from upstream of the turbine 66 of a turbocharger 60 and reintroduced into the intake manifold 50 after the compressor 64 as shown in FIGS. 4 and 5) or a low pressure loop EGR system 14 (e.g., exhaust gas is diverted from downstream of the turbine 66 of a turbocharger 60 and reintroduced into the intake manifold 50 before the compressor 64 of the turbocharger 60 as shown in FIG. 6). In certain embodiments with a low pressure loop EGR system 14, the high pressure energy fluid may be diverted from the EGR circuit 40 and reintroduced into the EGR circuit 40 at another location to promote or drive the EGR flow in the EGR circuit 40. For example, the sources for the high pressure energy fluid may be located between the exhaust manifold 52 and the turbine 66 of the turbocharger 60, between the compressor 64 of the turbocharger 60 and the intercooler 62, and/or between the intercooler 62 and the intake manifold 50. The locations for the injection of the diverted high pressure energy fluid (in the low pressure loop EGR system 14), via the one or more jet pumps 36, may be between the turbine 66 of the turbocharger 60 and an inlet of the EGR cooler unit 74 and/or between an outlet of the EGR cooler unit 74 and the EGR valve 78. In certain embodiments with a high pressure loop EGR system, the high pressure energy fluid may obtained from a high pressure (“blow-through”) fuel supply system 94 (e.g., where a fuel supply pressure is greater than a boost pressure produced by the compressor 64 of the turbocharger 60). In these embodiments, the injection point for high pressure energy fluid (e.g., gaseous fuel) may be the intake manifold 50 (e.g., before the throttle 54). Utilization of the high pressure energy fluid (e.g., sometimes from high pressure “waste” energy sources), in conjunction with the one or more jet pumps 36, to drive the circulation of the exhaust gas or EGR flow in the EGR circuit 40 minimizes or avoids the need for increasing the engine backpressure, thus, improving the efficiency of the engine 12. In addition, the injection of the high pressure energy fluid may be utilized during full speed and load conditions as well as during transient events. Further, the injection of the high pressure energy fluid utilizing the one or more jet pumps 36 promotes the EGR flow with zero moving parts, thus, providing a robust mechanical solution.

[0019] The engine 12 may be a two-stroke engine, four-stroke engine, or other type of engine 12. In particular, embodiments, the engine 12 is a four-stroke engine. The engine 12 may also include any number of combustion chambers, pistons, and associated cylinders (e.g., 1-24) in one (e.g. inline) or more (e.g., left and right cylinder banks) cylinder banks of a V, W, VR (a.k.a. Vee-Inline), or WR cylinder bank configuration. For example, in certain embodiments, the system 8 may include a large-scale industrial reciprocating engine having 6, 8, 12, 16, 20, 24 or more pistons reciprocating in cylinders. In some such cases, the cylinders and/or the pistons may have a diameter of between approximately 13.5-31 centimeters (cm). In certain embodiments, the cylinders and/or the pistons may have a diameter outside of the above range. The fuel utilized by the engine 12 may be any suitable gaseous fuel, such as natural gas, associated petroleum gas, hydrogen (Eb), propane (C3H8), biogas, sewage gas, landfill gas, coal mine gas, butane (C4H10), ammonia (NH3) for example. The fuel may also include a variety of liquid fuels, such as gasoline, diesel, methanol, or ethanol fuel. The fuel may be admitted through either a high pressure (blow-through) fuel supply system or low pressure (draw-through) fuel supply system or direct injection. In certain embodiments, the engine 12 may utilize spark ignition. In other embodiments, the engine 12 may utilize compression ignition.

[0020] The system 10 includes an engine control module (ECM) or engine control unit (ECU) 16 (e.g., controller) operably coupled to communicate with the engine 12 and the EGR system 14. In addition, the ECM 16 is operably coupled to communicate with one or more sensors 18 and one or more actuators 20. The ECM 16 may be a single controller or multiple controllers housed in the same or separate housings. The sensors 18 may be coupled to one or more components of the engine 12, the EGR system 14, or other component of the engine system 10, and sense one or more operating characteristics of the engine 12, the EGR system 14, and/or the engine system 10 and output a signal representative of the operating characteristic. Some examples of typical engine operating characteristics include engine speed; a torque indicating characteristic, such as Intake Manifold Absolute Pressure (IMAP) or intake manifold density (IMD); a characteristic indicative of the power output of the engine determined from inputs into the engine, such as Brake Mean Effective Pressure (BMEP) or Indicated Mean Effective Pressure (IMEP) or other estimate; a characteristic indicative of the engine's air to fuel equivalence ratio, such as exhaust oxygen content; ambient and/or engine temperature; ambient pressure; ambient humidity; and others. Some examples of other characteristics that may be measured by sensors 18 include a power output of the engine from outputs of the engine, for example, a generator driven by the engine, a throughput and pressure of a compressor driven by the engine, an engine loading measured with load cell and others. The actuators 20 are adapted to control various engine system components (not specifically shown) used in controlling the engine 12, the EGR system 14, and other engine system components. Some examples of typical engine components include a throttle, a turbocharger, a turbocharger compressor bypass or wastegate, air/fuel regulating device, such as an adjustable fuel mixer, a fuel pressure regulator, fuel injectors, carburetor, one or more EGR valves and others. The ECM 16 may also be coupled to communicate with other components 22. Some examples of other components 22 can include a user interface that allows a user to query the ECM 16 or input data or instructions to the ECM 16, one or more external sensors that sense information other than the operating characteristics of the engine or engine system, monitoring or diagnostic equipment to which the ECM 16 can communicate characteristics of the system, a load driven by the engine (e.g., generator, compressor, or other load) and others.

[0021] Referring to FIG. 2, the ECM 16 includes a processor 24 operably coupled to a non-transitory computer readable medium or memory 26. The computer readable medium 26 may be wholly or partially removable from the ECM 16. The computer readable medium 26 contains instructions used by the processor 24 to perform one or more of the methods described herein. More specifically, the memory 26 may include volatile memory, such as random access memory (RAM), and/or non-volatile memory, such as read-only memory (ROM), optical drives, hard disc drives, or solid-state drives. Additionally, the processor 24 may include one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs), one or more general purpose processors, or any combination thereof. Furthermore, the term processor is not limited to just those integrated circuits referred to in the art as processors, but broadly refers to computers, processors, microcontrollers, microcomputers, programmable logic controllers, application specific integrated circuits, and other programmable circuits. The ECM 16 can receive one or more input signals (inputi . . . inputn), such as from the sensors 18, actuators 20, and other components 22 and can output one or more output signals (outputi . . . outputn), such as to the sensors 18, actuators 20 and other components 22. [0022] The ECM 16 operates the engine 12 (FIG. 1) to a specified operating state, for example a specified speed, torque output, or other specified operating state, and maintain the engine in steady state operation. To this end, the ECM 16 receives input from the sensors 18, including engine state parameters, and determines and outputs one or more actuator control signals adapted to control the actuators 20 to operate the engine 12. The ECM 16, as described in greater detail below, also operates the EGR system 14 based on the input from the sensors 18. The following are non-limiting examples of sources (e.g., sensors, techniques, etc.) that the ECM 16 may utilize in estimating or calculating an amount or rate of EGR flow: Coriolis flow meter, hot wire anemometer, laminar flow meter, ultrasonic flow meter, Vortex shedding meter, differential pressure (DR; across engine, EGR circuit, or individual component), and net difference method (fuel for power, air for l, total from speed density). In certain embodiments, an additional method for estimating or calculating an amount or rate of EGR flow includes sampling gas concentrations of each chemical component (e.g., CO2, CO, NOx, N2, VOCs, HC, CH2O, NEE, etc.) from the intake manifold and comparing these to the additional flow streams that makeup the intake manifold flow (e.g., ambient air, fuel, closed crankcase ventilation (CCV), and EGR) as part of the total engine flow. Some of these chemical components only come from the exhaust (i.e., EGR). Thus, if the intake manifold concentrations are measured then a percent volumetric EGR flow can be estimated as it will be proportional when correcting for the state properties of the flow streams.

[0023] FIG. 3 is a schematic diagram of an embodiment of a jet pump 28 utilized to inject a high pressure energy fluid into an EGR circuit. The jet pump 28 is a simplified device based off the principle of conservation of momentum, which uses a relatively low volume flow rate high velocity motive jet to move a suction fluid at a much larger volume flow rate than what would otherwise be possible without the motive fluid influence. In particular, a portion of a conduit 30 for the high pressure energy source coupled to a portion of a conduit 32 for the EGR circuit 40 (see FIGS. 4-6) includes a tapered end 34 that generates the high velocity motive jet of the high pressure energy source. The high velocity motive jet of the high pressure energy source, in conjunction with the pumping effect (e.g., exertion of a force from a pressure differential at the interface of the conduits 30, 32), moves the fluid within the EGR circuit at a larger volume flow rate. For a typical gaseous fueled engine at rated power, running standard commercial quality natural gas (CQNG), it is typical for the volumetric flow rates to be the following of the total engine flow (Vfuei+Vair+VEGR): Vfuei approximately 5 to 6.5 percent, Vair approximately 50 to 63.5 percent, VEGR approximately 30 to 45 percent, where Vfuei, Vair, and VEGR represent the volumetric flow rates of fuel, air and EGR, respectively. This means that the ideal ratio of volumetric entrainment ratio achievable of Vfuei/VEGR is approximately 4.7-9. Even if the volumetric entrainment ratio is not ideal, there exists the simple fact that some amount, even if minimal, of flow acceleration is imparted on the EGR by the motive high pressure energy fluid (e.g., fuel, exhaust gas, or a combination of air, fuel, and exhaust gas).

[0024] FIG. 4 is a schematic diagram of the engine driven power generation system 10 of FIG. 1 utilizing a low pressure loop EGR system (e.g., exhaust gas is diverted from downstream of the turbine of the turbocharger (TC) and reintroduced into the intake manifold before the compressor of the turbocharger (TC)) having one or more jet pumps 36. As depicted, the engine 12 includes cylinder bank 38 and EGR circuit 40. In certain embodiments, the engine 12 may include multiple cylinder banks and/or EGR circuits. Each combustion chamber 42 includes a respective cylinder head 44. Each cylinder head 44 includes multiple assemblies including a respective piston disposed within a respective cylinder (not shown). Fuel is provided to a combustion chamber 42 in each cylinder while an oxidant (e.g., air) is provided to the combustion chamber 42 via an intake valve(s) 46 where combustion occurs and an exhaust valve(s) 48 controls discharge of exhaust from the engine 12. The cylinder bank 38 includes an intake manifold 50 (or intake system), an exhaust manifold 52 (or exhaust system), and a throttle 54. The throttle 54, compressor bypass valve 56, and wastegate 58 are the primary power controls that define the amount of oxidant/fuel delivered to the combustion chamber 42. In certain embodiments, other power controls may include variable turbine geometry or variable valve timing. [0025] As illustrated, the system 10 also includes one or more turbochargers 60 and one or more intercoolers or charge air cooler 62 (e.g., a heat exchanger) associated with the EGR circuit 40. In certain embodiments, an e-compressor (e.g., having an electric motor coupled to a compressor) may be utilized in place of the turbocharger 60. In certain embodiments, a multi-stage turbocharging system may be utilized. The turbocharger 60 includes a compressor 64 coupled to a turbine 66 (e.g., via a drive shaft (not shown)). Air (e.g., oxidant) is provided via an intake 68. In certain embodiments, air filters may be disposed within the intake 68. The turbine 66 is driven by exhaust gas to drive the compressor 64, which in turn compresses the intake air, fuel, and EGR flow that is provided to the intake manifold 50 after cooling by the intercooler 62. In addition, fuel is supplied from a fuel supply system 70 downstream of the intake 54 and upstream of the compressor 50. As depicted, the fuel supply system 70 is a low pressure (draw-through) fuel supply system. In a low pressure (LP) fuel system, low gas pressure is utilized by mixing the gas (fuel) with air at atmospheric pressure, or slightly sub-atmospheric pressure, before the compressor 50 in an air/fuel mixing chamber 72. The air fuel mixture is then drawn though the compressor 64 (along with the EGR flow) and compressed. Since the fuel mixes at ambient conditions, changes in these conditions will affect engine performance. Typical gas (fuel) pressures to the engine fuel regulator (not shown) fall in the range of 0.5 to 5 psig. In certain embodiments, the fuel supply system 70 may be a high pressure (HP) fuel supply system (e.g., HP fuel supply system 94 in FIG. 6). With the high pressure fuel system 94, a turbocharged engine needs gas (fuel) supply pressures to be greater than the boost pressure produced by the compressor 64. Since the fuel is introduced to the air stream after the air passes through the compressor 64, this differential pressure (i.e., gas over air pressure) allows for proper blending of the fuel and air in the carburetor. Typical gas (fuel) pressures to the engine fuel regulator fall in the range of 12 to 90 psig. In certain embodiments, the fuel supply system 70 may include a control device to regulate the air and fuel provided to the engine 12.

[0026] A wastegate 58 (e.g., wastegate valve) may be disposed between exhaust manifold discharge (from the exhaust manifold 52) and the turbine 66 to regulate the turbocharger 60 by diverting exhaust energy from the turbine 66. The wastegate 46 functionally regulates the amount of engine exhaust provided to the turbine 66 of the turbocharger 60 and thus the compressor discharge pressure produced by the compressor 64. The wastegate 58 may be of an integral type (e.g., with the turbine 66), an electronically controlled wastegate (e-wastegate), or a pneumatic wastegate that senses pressure elsewhere within the system 10. The system 10 may also include a respective bypass valve 56 (e.g., compressor bypass valve (CBV)) associated with each compressor 64 of each turbocharger 60 to control pressure by diverting a portion of the intake flow to the engine 12. As depicted the compressor bypass valve 56 is separate from the compressor 64. In certain embodiments, the compressor bypass valve 56 is integrated within the compressor 64.

[0027] Disposed downstream of the turbine 66 along the EGR circuit 40 is an EGR cooler unit 74. In certain embodiments, the EGR cooler unit 74 includes multiple functional segments. For example, the EGR cooler unit 74 may include a high temperature non-condensing cooler, a low temperature condensing cooler, an adiabatic gas/liquid separator, and a reheater. The reheater may utilize engine coolant, sometimes referred to as jacket water to heat the EGR flow to the desired temperature. Each of the high temperature non-condensing cooler, the low temperature condensing cooler, and reheater may include a separate coolant line, known as an auxiliary coolant circuit, or may utilize jacket water. In addition, the high temperature non-condensing cooler, the low temperature condensing cooler, and reheater may be interconnected to a hydraulic integration circuit 76, which may be part of the Balance of Plant (BoP). In certain embodiments, the EGR cooler unit 74 includes at least two of these functional sections. In certain embodiments, the EGR cooler unit 74 may include more than one of each functional section.

[0028] The EGR circuit 30 of the EGR system 14 includes an EGR valve 78 disposed downstream from the exhaust manifold 52 and upstream from the compressor 64. In particular, the EGR valve 78 is located on the cold side of the EGR cooler unit 74 to keep the EGR valve 78 near ambient temperature. The EGR valve 78 when opened enables EGR flow to an EGR mixing chamber 80 (e.g., where the air/fuel mixture and the EGR flow are mixed) and then to the compressor 64 and subsequently to the intake manifold 50 of the engine 12.

[0029] Although a portion of the exhaust in the circuit 40 is diverted toward the EGR cooler unit 74, the remaining portion of the exhaust is diverted to an exhaust aftertreatment system 82. In certain embodiments, the exhaust aftertreatment system 82 may include a three-way catalyst to reduce exhaust emissions (e.g., nitrogen oxides (NOx), hydrocarbons (HC), carbon monoxide (CO), and other emissions).

[0030] The EGR system 14 includes one or more conduits 84 branching off from one or more different locations along the EGR circuit 40 to provide or communicate a high pressure energy fluid to another location along the EGR circuit 40 to promote movement of the EGR flow or exhaust gas along the EGR circuit 40. Each conduit 84 includes a respective jet pump 36 (e.g., as shown in FIG 3) located where the conduit 84 meets EGR circuit 40 for the jet pump 36 to inject the high pressure energy fluid into the EGR circuit 40 (e.g., respective conduit 84 of the EGR circuit 40 at injection location). In certain embodiments, each conduit 84 may include a respective valve 86 that may modulate flow of the high pressure energy fluid along the conduit 84 in response to control signals from the ECM 16.

[0031] In certain embodiments, the high pressure energy fluid may be derived from a waste source (e.g., compressor bypass valve discharge fluid, a wastegate valve discharge fluid, etc.). For example, as depicted, a conduit 88 extends from a conduit associated with the wastegate 58 that provides the high pressure energy fluid for injection. Thus, the high pressure energy fluid in conduit 88 is exhaust gas diverted from a location between the exhaust manifold 52 and the turbine 66. Although the conduit 88 is shown extending from the wastegate 58 and its associated conduit, it may extend from another location upstream of the wastegate 58 between the turbine 66 and the exhaust manifold 52 (e.g., as shown with conduit 89). As depicted, the jet jump 36 of the conduits 88, 89 injects the high pressure energy fluid in the EGR circuit 40 at a location (e.g., hot side piping) between the turbine 66 and an inlet of the EGR cooler unit 74. In other embodiments, the jet pump 36 of the conduit 88, 89 may inject the high pressure energy fluid at a location (e.g., cold side piping) between an outlet of the EGR cooler unit 74 and EGR valve 78 (see FIG. 5). These two injection locations are non-limiting examples of locations for injection of the high pressure energy fluid via the conduits 88, 89. The high pressure energy fluid may be injected at other locations besides these two locations via the conduit 88, 89.

[0032] In another example, as depicted, a conduit 90 extends from a conduit associated with the compressor bypass valve 56 that provides the high pressure energy fluid for injection. Thus, the high pressure energy fluid in conduit 90 is a mixture of exhaust gas, air, and fuel diverted from a location between the compressor 64 and the intercooler 62. Although the conduit 90 is shown extending from the compressor bypass valve 56 and its associated conduit, it may extend from another location between the compressor 64 and the intercooler 62. As depicted, the jet pump 36 of the conduit 88 may inject the high pressure energy fluid at a location (e.g., cold side piping) between an outlet of the EGR cooler unit 74 and EGR valve 78. In other embodiments, the jet jump 36 of the conduit 90 injects the high pressure energy source in the EGR circuit 40 at a location (e.g., hot side piping) between the turbine 66 and an inlet of the EGR cooler unit 74 (see FIG. 5). These two injection locations are non-limiting examples of locations for injection of the high pressure energy fluid via the conduit 90. The high pressure energy fluid may be injected at other locations besides these two locations via the conduit 90.

[0033] High pressure energy fluid may be also be diverted from other locations along the EGR circuit 40. For example, as depicted, a conduit 92 extends from between the intercooler 62 and the intake manifold 50. Thus, the high pressure energy fluid (e.g., intercooler discharge) in conduit 92 is a mixture of exhaust gas, air, and fuel. As depicted, the jet pump 36 of the conduit 92 may inject the high pressure fluid energy fluid at a location (e.g., cold side piping) between an outlet of the EGR cooler unit 74 and EGR valve 78. In other embodiments, the jet jump 36 of the conduit 92 injects the high pressure energy source in the EGR circuit 40 at a location (e.g., hot side piping) between the turbine 66 and an inlet of the EGR cooler unit 74 (see FIG. 5). These two injection locations are non limiting examples of locations for inj ection of the high pressure energy fluid via the conduit 92. The high pressure energy fluid may be injected at other locations besides these two locations via the conduit 92.

[0034] In certain embodiments, the EGR system 14 may only include one of the conduits 88, 89, 90, 92 and associated jet pumps 36 for injecting the high pressure energy fluid into the EGR circuit 40. In other embodiments, the EGR system 14 may include two or more of the conduits 88, 89, 90, 92 and associated jet pumps 36 for injecting the high pressure energy fluid into the EGR circuit 40. The number of conduits 84 and associated jet pumps 36 may vary (e.g., 1, 2, 3, 4, or more). Each conduit 84 may only include a single injection point and a single jet pump 36. In certain embodiments, each conduit 84 may include two or more injection points and a respective jet pump 36 for each injection point. The source for the high pressure energy fluid for a respective conduit 84 may derive from any location along the EGR circuit 40.

[0035] Various components (or actuators for these components) of the system 10, the engine 12, and the EGR system 14 may be in communication with the ECM 16. For example, the EGR valve 78, the throttle 54, the compressor bypass valves 56, the wastegate valve 58, the valve(s) 86, and/or the fuel supply system 70 (including the air/fuel control device) may be communicatively coupled to the ECM 16 to enable the ECM 16 to control these components.

[0036] FIG. 6 is a schematic diagram of the engine driven power generation system 10 of FIG. 1 utilizing a high pressure loop EGR system (e.g., exhaust gas is diverted from upstream of the turbine and reintroduced into the intake manifold after the compressor) having one or more jet pumps 36. The system 10 in FIG. 6 is as described in FIGS. 4 and 5 except for a few differences. As depicted in FIG. 6, the EGR cooler unit 60 of each EGR circuit is disposed downstream of the exhaust manifold 52 and upstream of the turbine 60. In addition, the EGR flow is introduced from the EGR cooler unit 74 downstream of the compressor 64 between the intercooler 62 and the intake manifold 50. Further, the fuel is introduced within the air (e.g., at air/fuel mixing chamber 72) and exhaust (e.g., at EGR mixing chamber 80) between the intercooler 62 and the intake manifold 50. In certain embodiments, the air, fuel, and exhaust may be mixed in a single chamber (e.g., EGR mixing chamber 80). As depicted, the fuel supply system 94 is a high pressure (blow- through) fuel supply system. In certain embodiments, the high pressure fuel supply system 94 may take the form of individual gas mixing achieved by intake port injection (not shown). With a high pressure (HP) fuel system, a turbocharged engine needs gas (fuel) supply pressures to be greater than the boost pressure produced by the turbocharger compressor. Since the fuel is introduced to the air stream downstream of the turbocharger compressor, this differential pressure (i.e., gas over air pressure) allows for proper blending of the fuel and air in the carburetor and should be approximately 5 inch (127 mm) water column higher than the air pressure in the carburetor to get proper mixing. Typical gas (fuel) pressures to the engine fuel regulator fall in the range of 12 to 90 psig. In certain embodiments, the fuel supply system 94 may include a control device to regulate the air and fuel provided to the engine.

[0037] As depicted, the high pressure fuel supply system 94 is utilized as the high pressure energy source (e.g., fuel) to promote movement of the EGR flow or exhaust gas along the EGR circuit 40. A conduit 96 extends from the high pressure fuel supply system 94 that provides the high pressure energy fluid for injection. The conduit 96 includes a respective jet pump 36 (e.g., as shown in FIG 3) located where the conduit 96 meets EGR circuit 40 to inject the high pressure energy fluid into the EGR circuit 40 (e.g., respective conduit of the EGR circuit at injection location). In certain embodiments, the conduit 96 may include a valve 86 that may modulate flow the high pressure energy fluid source along the conduit 96 in response to control signals from the ECM 16. As depicted, the jet pump 36 of the conduit 96 may inject the high pressure fluid energy in the intake manifold 50 (e.g., upstream of the throttle 54). In certain embodiments, the jet pump 36 of the conduit 96 may inject the high pressure fluid energy fluid at a location (e.g., cold side piping) between an outlet of the EGR cooler unit 74 and EGR valve 78 (as shown by the dashed arrow). In other embodiments, the jet jump 36 of the conduit 96 may inject the high pressure energy source in the EGR circuit 40 at a location (e.g., hot side piping) between the turbine 66 and an inlet of the EGR cooler unit 74 (as shown by the dashed arrow). These injection locations are non-limiting examples of locations for injection of the high pressure energy fluid via the conduit 96. The high pressure energy fluid may be injected at other locations besides these locations via the conduit 96.

[0038] In the case of high pressure (HP) fuel system carbureted premixed charge engines, fuel is admitted just before the throttle 54 to use the throttle 54 to help facilitate better mixing of fuel and air. Fuel is introduced downstream of both the turbocharger compressor 64 and the charge air cooler or intercooler 62, which contain air only. This is the most efficient configuration as it delays the dilution of air as to not impact the thermodynamic processes associated with these components. As the fuel from the high pressure fuel supply 94 is the motive force for the high pressure EGR (HP -EGR), the location where EGR is admitted may coincide with where the fuel is admitted. For this reason, the optimal admission location for fuel and EGR (with the fuel source being from the jet pump 36) is in the intake manifold 50 before the throttle 54. As depicted, conduit 90 extends from the HP fuel supply system 95 to the intake manifold 50. In the case of port injection engines, fuel is admitted in the intake manifold runners that leads to individual, or in rare cases multiple, cylinder heads. The simultaneous admission of fuel and EGR (with the fuel source being from the jet pump 36) in the individual intake manifold runners is not desirable. However, in certain embodiments, the fuel and EGR, along with the fuel injected via the jet pump 36, may be injected upstream of the port fuel injectors, like at the entrance to the fuel manifold/rail, such that the injectors admit a higher volumetric flow rate of combined fuel and EGR rather than a smaller volume of fuel alone.

[0039] For a gaseous fueled engine, mixing is important to ensure a homogeneous charge mixture (fuel+air+diluent) is distributed to each cylinder for combustion. Use of a gas-gas ejector helps facilitate mixing between the fuel and EGR diluent components, taking some of the burden off mixing with the air (oxidant). [0040] Fundamentally, with any power producing reciprocating internal combustion engine, fuel is needed during operation. In the case of gaseous fueled engines there always exists the potential for high pressure EGR (HP-EGR), of a greater pressure than the turbocharger compressor discharge pressure, to receive flow acceleration from the high pressure fuel supply system 94. The drawback with using the high pressure fuel supply system 94 to provide the high pressure energy fluid in the jet pump 36 is that the high pressure fuel supply system 94 may incur additional non-recoverable pressure losses than it would otherwise not have if the jet pump 36 was not being utilized. This means that the high pressure fuel supply pressure requirement to the regulator when used with the jet pump 36 would be higher than the high pressure fuel supply requirement for a comparable application without the jet pump 36. This additional fuel pressure requirement may marginally limit application of where such an engine system may be installed, but typically for locations that already have a high pressure fuel supply there is existing margin in the fuel regulation prior to admission into the engine.

[0041] Since the HP fuel supply system 94 is being used as the source for the motive jet to move the suction EGR fluid, the flow acceleration efficiency of the high pressure EGR (HP-EGR) is dependent on any variation in the fuel. Most notably, variation in the form of fuel quality, which is a change to the calorific value of a fuel. Using commercial quality natural gas (CQNG) as the standard, many fuels have a lower calorific value including petroleum gas, propane (C3H8), butane (C4H10), ammonia (ME), etc. High diluent fraction low BTU value fuels, such as biogas, sewage gas, landfill gas, coal mine gas, digester gas, contain widely varying amounts of contaminants and diluents such as carbon dioxide, nitrogen, water vapor, hydrogen sulfide (H2S), siloxanes, chlorinated hydrocarbons, and other trace gases in the fuel composition. Use of low BTU value fuels in an engine require a higher volumetric flow rate of fuel to maintain the same engine power due to the calorific value deficit compared to that of a standard commercial quality natural gas (CQNG). This means, in circumstances where low BTU value fuels are used the high pressure EGR (HP-EGR) would receive additional flow acceleration due to the additional fuel volumetric flow rate of the motive jet within the jet pump 36. However, the application of low BTU value fuels for an EGR engine tends to be limited by the manufacturer due to the corrosive chemical components typically associated with these fuels. High BTU fuels such as pure methane (CH4) and hydrogen (H2) could result in a diminished flow acceleration of an ejector compared to that of a standard commercial quality natural gas (CQNG).

[0042] An additional benefit of combining the high pressure EGR (HP -EGR) fluid and the fuel admission in the jet pump 36 is that, above a minimal power threshold where additional diluent is not required by the engine (e.g., approximately 40 percent rated power), the required supply of high pressure EGR (HP-EGR) fluid correlates with the demanded fuel system quantity. This trending reduces the requirements of a high pressure EGR (HP-EGR) control valve. With the natural trending of EGR fluid provided with power (i.e., fuel quantity) in the ejector, acting as a course adjustment of the EGR mass flow, in series with a single EGR control valve for fine adjustment the combination is of finer flow control resolution than the EGR control valve alone. Having these two components in series (e.g., ejector to EGR valve, or vice versa), there is the potential for ultrafme EGR mass flow resolution control functionality beyond what would normally be possible with just an EGR control valve. Valves typically have limitations on their functionality such as deadband (e.g., if there is significant play in the valve actuator system and there will be a period when the valve does not move), minimum positioning precision/resolution of the controlling actuators, dithering between two positions to pseudo-replicate an intermediary flow position that is not possible, turndown ratio (referring to the width of the operational range of a device, and is defined as the ratio of the maximum capacity to minimum capacity), and other limitations. Functionally, this may be important for an engine using EGR because the location of maximum efficiency is typically near a border of the combustion operating range/window (e.g., knock border, exhaust gas temperature limit, misfire limit, peak firing pressure limit, etc.). This manipulation of the EGR valves enables maintaining maximum efficiency of the engine without allowing variations in EGR flow to cause combustion to operate outside of its designed combustion operating range/window (e.g., knock border, exhaust gas temperature limit, misfire limit, peak firing pressure limit, exhaust emissions aftertreatment system operation window, etc.) where the mechanical health or emissions compliance of the engine would be at risk.

[0043] Technical effects of the disclosed embodiments include providing a system for injecting a high pressure energy fluid via one or more jet pumps (e.g., ejectors such as gas- gas ejectors) at one or more locations along an EGR circuit of an EGR system, which provides the pumping effect, to cause exhaust gas to move along the EGR circuit. Utilization of the high pressure energy fluid (e.g., sometimes from high pressure “waste” energy sources), in conjunction with the one or more jet pumps, to drive the circulation of the exhaust gas or EGR flow in the EGR circuit minimizes or avoids the need for increasing the engine backpressure, thus, improving the efficiency of the engine. In addition, the injection of the high pressure energy fluid may be utilized during full speed and load conditions as well as during transient events. Further, the injection of the high pressure energy fluid utilizing the one or more jet pumps promotes the EGR flow with zero moving parts, thus, providing a robust mechanical solution.

[0044] This written description uses examples to disclose the subject matter, including the best mode, and also to enable any person skilled in the art to practice the subject matter, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

[0045] The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for [performjing [a function]...” or “step for [performing [a function] . it is intended that such elements are to be interpreted under 35 U.S.C. 112(f). However, for any claims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112 (f).

Claims

CLAIMS:

1. A system, comprising: an internal combustion engine comprising an intake manifold and an exhaust manifold; an exhaust gas recirculation (EGR) system coupled to the internal combustion engine and configured to route exhaust gas generated by the industrial internal combustion engine from the exhaust manifold to the intake manifold, wherein the EGR system comprises: an EGR circuit; a turbocharger comprising a turbine and a compressor; an EGR cooler unit coupled to the turbocharger and the manifold system; and an EGR valve configured to regulate an amount of the exhaust gas recirculated to the intake manifold of the internal combustion engine; and at least one jet pump disposed along the EGR circuit of the EGR system, wherein the at least one jet pump is configured to inject a high pressure energy fluid into the EGR circuit and to provide a pumping effect to cause the exhaust gas to move along the EGR circuit.

2. The system of claim 1, wherein the EGR system comprises a low pressure loop EGR system.

3. The system of claim 2, wherein an injection point for the at least one jet pump to inject the high pressure energy fluid is located between the turbine of the turbocharger and an inlet of the EGR cooler unit.

4. The system of claim 2, wherein an injection point for the at least one jet pump to inject the high pressure energy fluid is located between an outlet of the EGR cooler unit and the EGR valve.

5. The system of claim 2, wherein a source for the high pressure energy fluid is located between the exhaust manifold and the turbine of the turbocharger.

6. The system of claim 2, wherein a source for the high pressure energy fluid is located between the compressor of the turbocharger and the intercooler.

7. The system of claim 2, wherein a source for the high pressure energy fluid is located between the intercooler and the intake manifold.

8. The system of claim 2, wherein the high pressure energy fluid comprises a compressor bypass valve discharge fluid, a wastegate valve discharge fluid, or an intercooler discharge fluid.

9. The system of claim 1, wherein the EGR system comprises a high pressure loop EGR system.

10. The system of claim 9, wherein a source for the high pressure energy fluid comprises a high pressure fuel supply system where a fuel supply pressure is greater than a boost pressure produced by the compressor of the turbocharger.

11. The system of claim 10, wherein an injection point for the at least one jet pump to inject the high pressure energy fluid is the intake manifold upstream of a throttle.

12. An exhaust gas recirculation (EGR) system in combination with an internal combustion engine, comprising: a low pressure EGR circuit; and at least one jet pump located in flow of the low pressure EGR circuit of the EGR system, wherein the at least one jet pump is configured to inject a high pressure energy fluid into the low pressure EGR circuit and to provide a pumping effect to cause an exhaust gas from the internal combustion engine to move along the low pressure EGR circuit.

13. The EGR system in combination with the internal combustion engine of claim 12, wherein the internal combustion engine comprises an intake manifold and an exhaust manifold, and wherein the EGR system comprises a turbocharger comprising a turbine and a compressor, an EGR cooler unit coupled to the turbocharger and the intake manifold, and an EGR valve configured to regulate an amount of the exhaust gas recirculated to an intake manifold of the internal combustion engine.

14. The EGR system in combination with the internal combustion engine of claim 13, wherein an injection point for the at least one jet pump to inject the high pressure energy fluid is located between the turbine of the turbocharger and an inlet of the EGR cooler unit.

15. The EGR system in combination with the internal combustion engine of claim 13, wherein an injection point for the at least one jet pump to inject the high pressure energy fluid is located between an outlet of the EGR cooler unit and the EGR valve.

16. The EGR system in combination with the internal combustion engine of claim 13, wherein the high pressure energy fluid comprises a compressor bypass valve discharge fluid, a wastegate valve discharge fluid, or an intercooler discharge fluid.

17. The EGR system in combination with the internal combustion engine of claim 13, wherein a source for the high pressure energy fluid is located between the exhaust manifold and the turbine of the turbocharger, between the compressor of the turbocharger and the intercooler, between the intercooler and the intake manifold.

18. An exhaust gas recirculation (EGR) system in combination with an internal combustion engine, comprising: a high pressure fuel source configured to provide a high pressure fuel to the internal combustion engine; a high pressure EGR circuit; and at least one jet pump located in flow of the high pressure EGR circuit of the EGR system, wherein the at least one jet pump is connected in communication with the high pressure fuel source and is configured to inject the high pressure fuel into the high pressure EGR circuit and to provide a pumping effect to cause an exhaust gas from the internal combustion engine to move along the high pressure EGR circuit.

19. The EGR system in combination with the internal combustion engine of claim 18, wherein a pressure of the high pressure fuel is greater than a boost pressure produced by a compressor of a turbocharger of the internal combustion engine.

20. The EGR system in combination with the internal combustion engine of claim 18, wherein an injection point for the at least one jet pump to inject the high pressure fuel is the intake manifold upstream of a throttle.