System and method for injecting condensate into the cylinder of a piston engine

Abstract

[0090] A system includes a condensate injection system configured to be fluidly coupled to a combustion chamber of a reciprocating engine and an exhaust gas recirculation (EGR) system of the reciprocating engine. The condensate injection system includes a condensate reservoir configured to store condensate collected by the EGR system. The condensate injection system also includes a pump fluidly coupled to the condensate reservoir. The condensate injection system also includes an injector fluidly coupled to the pump. The injector is configured to inject condensate into the combustion chamber during a first portion of an engine cycle of the reciprocating engine. The first portion of the engine cycle includes at least a portion of a power stroke and / or an exhaust stroke of the engine cycle.

Description

BACKGROUND

[0001] The subject matter disclosed herein relates to piston engines and associated heat exchangers.

[0002] A combustion system may include an exhaust gas recirculation (EGR) system configured to recirculate exhaust gases from an exhaust to an inlet of a reciprocating engine. The EGR system may generate condensate due to cooling of the exhaust gases via a set of heat exchangers. The condensate is removed from the combustion system via a drain system, such that the condensate is a byproduct of the operation of the combustion system. Accordingly, there is a need to reduce the amount of condensate removed via a drain system. SHORT DESCRIPTION

[0003] Specific embodiments, corresponding to the scope of the originally claimed subject matter, are summarized below. These embodiments are not intended to limit the scope of the claimed subject matter; 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 certain embodiments, a system includes a condensate injection system configured to be fluidly coupled to a combustion chamber of a piston engine and an exhaust gas recirculation (EGR) system of the piston engine. The condensate injection system includes a condensate reservoir configured to store condensate collected from the EGR system. The condensate injection system also includes a pump fluidly coupled to the condensate reservoir. The condensate injection system also includes an injector fluidly coupled to the pump. The injector is configured to inject condensate into the combustion chamber during a first portion of an engine cycle of the piston engine. The first portion of the engine cycle includes at least a portion of a power stroke and / or an exhaust stroke of the engine cycle.

[0005] In certain embodiments, a system includes a controller having a processor, a memory, and instructions stored in the memory and executable by the processor to control a condensate injection system configured to be fluidly coupled to a combustion chamber of a reciprocating engine and an exhaust gas recirculation (EGR) system of the reciprocating engine. The condensate injection system includes a condensate reservoir configured to store condensate collected from the EGR system. The condensate injection system also includes a pump fluidly coupled to the condensate reservoir. The condensate injection system also includes an injector fluidly coupled to the pump. The controller is configured to control the injector to inject condensate into the combustion chamber during a first portion of an engine cycle of the reciprocating engine.The first portion of the engine cycle comprises at least a portion of a power stroke and / or an exhaust stroke of the engine cycle.

[0006] In certain embodiments, a method includes controlling, via a controller, a condensate injection system configured to be fluidly coupled to a combustion chamber of a piston engine and an exhaust gas recirculation (EGR) system of the piston engine. The condensate injection system includes a condensate reservoir configured to store condensate collected from the EGR system. The condensate injection system also includes a pump fluidly coupled to the condensate reservoir. The condensate injection system also includes an injector fluidly coupled to the pump. Controlling includes commanding the injector to inject the condensate into the combustion chamber during a first portion of an engine cycle of the piston engine. The first portion of the engine cycle includes at least a portion of a power stroke and / or an exhaust stroke of the engine cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] These and other features, aspects, and advantages of the present disclosure will be 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: Fig. 1 is a diagram of an embodiment of a combustion system having a condensate injection system coupled to a recirculation line of an engine system; Fig. 2 is a schematic view of an embodiment of a piston-cylinder assembly with an injector coupled to the condensate injection system; Fig. 3 is a diagram of an embodiment of the combustion system of Fig. 1, further illustrating the condensate injection system coupled to the recirculation line and a piston engine of the combustion system; Fig. 4 is an embodiment of a graph illustrating internal pressure and crank angle during an engine cycle of the piston-cylinder assembly of Fig. 2; and Fig. 5 is a flowchart illustrating one embodiment of a process for controlling the condensate injection system of Fig. 2 shows. DETAILED DESCRIPTION

[0008] One or more specific embodiments of the present disclosure are described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation may be described in the specification. It should be noted that in developing any such actual implementation, as with any engineering or technical design project, numerous implementation-specific decisions must be made to achieve the developer's specific goals, such as adhering to system-related and operational constraints, which may vary from one implementation to another.Furthermore, it should be recognized that such a development effort may be complex and time-consuming, but nevertheless represents a routine undertaking of design, manufacture, and fabrication for those skilled in the art who will benefit from this disclosure.

[0009] When introducing elements of various embodiments of the present disclosure, the terms "a," "an," "the," and "said" mean that there is one or more of the elements. The terms "comprising," "including," and "having" are intended to be comprehensive and mean that there may be additional elements besides those listed.

[0010] The disclosed embodiments provide systems and methods for injecting condensate (e.g., water condensed from water vapor in the exhaust gases) collected by a heat exchanger assembly (e.g., exhaust gas cooling system, EGR cooling system) into a combustion chamber of a piston-cylinder assembly of a reciprocating engine via a condensate injection system during a portion of the engine cycle of the reciprocating engine. In particular, the portion of the engine cycle may include a final portion of a power stroke (e.g., combustion stroke) and an exhaust stroke of the engine cycle. Additionally, a controller may be configured to control the condensate injection system based on one or more signals received from one or more sensors located throughout the combustion system.

[0011] For example, the controller may be configured to monitor a temperature of an exhaust gas discharged into an exhaust system of the combustion system. If the temperature of the exhaust gas falls below a lower temperature threshold or rises above an upper temperature threshold, the controller may be configured to decrease or increase, respectively, the amount of condensate into the combustion chamber. By controlling the amount of condensate injected into the combustion cylinder based on the exhaust gas temperature, the controller may be configured to regulate the temperature of the exhaust gas between the lower and upper temperature thresholds. Furthermore, the controller may be configured to monitor an amount of condensate stored in a condensate tank of the condensate injection system.In particular, the controller may be configured to control the amount of condensate injected into the combustion chamber and / or the amount of condensate generated by the heat exchanger assembly based on the monitored amount of condensate in the condensate tank. For example, the controller may be configured to increase condensate consumption (e.g., by injection) and / or decrease condensate production when the amount of condensate in the condensate tank exceeds a high threshold. Additionally or alternatively, the controller may be configured to decrease condensate consumption (e.g., by injection) and / or increase condensate production when the amount of condensate in the condensate tank falls below a low threshold.Furthermore, the controller may be configured to monitor one or more parameters of the reciprocating engine to determine when to inject condensate into the combustion chamber. For example, the controller may be configured to use one or more maps (e.g., lookup tables of various parameters) of the combustion system to determine one or more parameters that are not directly measured (e.g., internal pressure of the combustion chamber). The controller may be configured to determine a crank angle corresponding to a start point and / or end point of the engine cycle for condensate injection based on the one or more parameters determined via the map representations.

[0012] Fig. 1 is a diagram of one embodiment of a combustion system 10 having a condensate injection system 12 coupled to a return line 14 of an engine system 16. The engine system 16 may include a reciprocating engine 18 with a heat exchange system 20 (e.g., EGR cooling system) and an exhaust system 22. As explained below, the condensate injection system 12 is configured to receive condensate (e.g., water condensed from water vapor in exhaust gas 30) from the heat exchange system 20, store the water in one or more condensate reservoirs, and deliver the condensate to the combustion chambers of the reciprocating engine 18 during a final portion of a power stroke and / or an exhaust stroke. Thus, the condensate injection system 12 is configured to control a temperature in the combustion chamber and the exhaust gas 30 while reducing or preventing condensate waste.Temperature control may be used to control exhaust emissions and protect downstream equipment (e.g., turbochargers, valves, etc.) from excessive temperatures in the exhaust gases 30. In certain embodiments, the condensate injection system 12 may rely solely on the condensate for injection into the combustion chambers of the piston engine 18 without an additional water supply. However, in some embodiments, the condensate injection system 12 may supplement the condensate with a separate water supply for injection into the combustion chambers of the piston engine 18. For example, the condensate injection system 12 may selectively supplement the condensate with the separate water supply when the condensate is insufficient to meet demand. Further details of the condensate injection system 12 are discussed below.

[0013] Piston engine 18 may comprise a four-stroke engine with a four-stroke cycle (e.g., intake stroke, compression stroke, power / expansion stroke, exhaust stroke). In certain embodiments, piston engine 18 may comprise a two-stroke engine or a five-stroke engine. Piston engine 18 may also comprise any number of combustion chambers, pistons, and associated cylinders (e.g., 1-24) in one cylinder bank (e.g., inline) or multiple cylinder banks (e.g., left and right cylinder banks) of a V, W, VR (also known as V-inline), or WR cylinder bank configuration. For example, in certain embodiments, piston engine 18 may comprise a large-displacement industrial piston engine including 6, 8, 12, 16, 20, 24, or more pistons reciprocating within cylinders. In some of these cases, the cylinders and / or pistons may have a diameter between approximately 13.5 and 31 centimeters (cm).In certain embodiments, the cylinders and / or pistons may have a diameter outside the above-mentioned range. The fuel used by the piston engine 18 may be any suitable gaseous fuel, such as natural gas, associated petroleum gas, hydrogen (H2), propane (C3H8), biogas, sewage gas, landfill gas, 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 supplied through either a high-pressure (blow-through) or low-pressure (induction) fuel supply system, or by direct injection. In certain embodiments, the fuel may be supplied via port fuel injection (PFI). In certain embodiments, the piston engine 18 may employ spark ignition.In other embodiments, the piston engine 18 may employ compression ignition.

[0014] The exhaust system 22 may include one or more exhaust circuits 28 between the piston engine 18 and the corresponding heat exchange system 20. The exhaust circuits 28 may be configured to direct one or more flows of exhaust gases 30 between the piston engine 18 and the heat exchange system 20. For example, the piston engine 18 may divert a flow of exhaust gas 30 and direct it along an exhaust conduit 32 to the heat exchange system 20, and recirculate the exhaust gas 30 from the heat exchange system 20 back into the piston engine 18 via one or more EGR (Exhaust Gas Recirculation) circuits 34.

[0015] The heat exchange system 20 coupled to the exhaust circuit 28 may include one or more heat exchanger assemblies 36, each of the heat exchanger assemblies 36 including a plurality of heat exchanger modules 37 coupled to one of a plurality of manifolds 38. For example, the heat exchanger assemblies 36 may include heat exchanger assemblies 40, 42, and 44, each of the heat exchanger assemblies 36 including one of the manifolds 38 (e.g., manifolds 46, 48, and 50). Each of the heat exchanger assemblies 36 may include any number of heat exchanger modules 37 arranged in a series arrangement, a parallel arrangement, or a combination thereof. For example, in certain embodiments, the heat exchanger modules 37 for each of the heat exchanger assemblies 36 with one of the manifolds 38 may include heat exchangers (e.g., EGR coolers) 52, 54, 56, and 58.Although four heat exchangers 52, 54, 56, and 58 are illustrated, any number of heat exchangers (e.g., up to an Nth heat exchanger) may be arranged in each of the heat exchanger assemblies 36. The heat exchangers 52, 54, 56, and 58 may be arranged in series, parallel, or a combination thereof. In certain embodiments, the heat exchangers 52 and 54 may be first-stage heat exchangers (e.g., arranged in parallel), the heat exchanger 56 may be a second-stage heat exchanger, and the heat exchanger 58 may be a third-stage heat exchanger. However, the heat exchanger modules 37 may be arranged in any number of stages, with each stage having 1, 2, 3, or more heat exchangers arranged in parallel.

[0016] The illustrated heat exchanger assemblies 40, 42, and 44 each include one of the manifolds 46, 48, and 50 with a plurality of heat exchanger modules 37, such as heat exchangers 52, 54, 56, and 58. The heat exchanger assemblies 40, 42, and 44 may include the same or a different configuration of the heat exchanger modules 37 and the manifolds 38, such as the same or a different number of heat exchanger modules 37, the same or a different number of sections forming the manifolds 38, or any combination thereof. Each of the manifolds 38 may represent a single one-piece manifold (e.g., cast single manifold), a multi-piece manifold (e.g., cast multi-manifold) with various manifold sections removably coupled together, or individual lines that couple the heat exchanger modules 37 together as a multi-line manifold.

[0017] In the illustrated embodiment, each heat exchanger assembly 36 includes a plurality of heat exchanger modules 37, such as a serial arrangement of heat exchangers 52, 54, 56, and 58, coupled to at least one of the manifolds 38. The heat exchanger modules 37 are also coupled to the exhaust conduit 32 and the EGR circuit 34 of the exhaust system 22 via the at least one manifold 38. A flow of the exhaust gas 30 may be configured to flow from the reciprocating engine 18 through the exhaust conduit 32 into one of the manifolds 38, through the heat exchanger modules 37, back through one of the manifolds 38, and then through the EGR circuit 34 for recirculation into an inlet of the reciprocating engine 18. In some embodiments, at least some or all of the exhaust gas 30 may not flow back into the reciprocating engine 18 via the EGR circuit 34.For example, at least a portion of the exhaust gas 30 may not enter the heat exchanger assembly 36 and may flow downstream into one of the exhaust waste heat recovery systems 106 and / or be vented to the environment.

[0018] Each manifold 38 can be configured such that the exhaust gases 30 of the reciprocating engine 18 circulate through each of the heat exchange modules 37, such as in a series and / or parallel arrangement, while one or more heat exchange fluids 142 also circulate through the manifold 38 and the heat exchange modules 37. For example, the heat exchange fluids 142 can include heat exchange fluids 144, 146, and 148. The heat exchange fluids 142 can include one or more fluids, such as condensate, antifreeze or additives, coolant, or any combination thereof. For example, the heat exchange fluids 142 can include a main engine fluid and an auxiliary fluid. For example, the main engine fluid can flow to, from, and through the reciprocating engine 18 such that the main engine fluid can be configured to provide cooling to the reciprocating engine 18.Similarly, the auxiliary fluid may flow to and from one or more auxiliary systems such that the auxiliary fluid may provide cooling. The auxiliary systems may and / or may not be related to the reciprocating engine 18, but the auxiliary systems may be external to or separate from the reciprocating engine 18. For example, auxiliary systems may include other power plant equipment, and the auxiliary fluid may be described as a balance-of-plant (BoP) fluid (e.g., BoP auxiliary coolant). Again, the manifold 38 for each heat exchanger assembly 36 may be configured to direct the inputs and outputs of both the exhaust gases 30 and the heat exchange fluids 142 (e.g., the main engine fluid and / or the auxiliary fluid) through each of the heat exchanger modules 37.

[0019] Accordingly, the heat exchanger assemblies 36 may transfer heat between the exhaust gas 30 and one or more of the heat exchange fluids 142, such as the main engine fluid and the auxiliary fluid. The heat exchanger modules 37 may be gas-to-liquid heat exchangers configured to transfer heat between the exhaust gas 30 and the liquid of the heat exchange fluids 142. In some embodiments, each of the heat exchanger modules 37 may be a plate heat exchanger, a brazed plate heat exchanger, and / or a gas-to-liquid plate heat exchanger.

[0020] In the illustrated embodiment, the heat exchanger assemblies 36 are disposed at three different locations throughout the exhaust system 22, as indicated by the heat exchanger assemblies 40, 42, and 44. However, the exhaust system 22 may include only one or two of the heat exchanger locations (e.g., the heat exchanger assemblies 40, 42, and 44). The piston engine 18 includes an engine block 170 having a plurality of piston-cylinder assemblies 172, each having a piston 174 disposed within a cylinder 176. Each piston 174 may be configured to reciprocate within the cylinder 176 in response to combustion in a combustion chamber of the engine block 170, thereby driving the rotation of a crankshaft coupled to a shaft 178 that drives a load 180 (e.g., an electric generator). In addition, the piston engine 18 includes an exhaust manifold 182 and an intake manifold 184.The intake manifold 184 is coupled to an intake circuit 186 of an intake system 188, while the exhaust manifold 182 is coupled to the exhaust circuit 28 of the exhaust system 22. The intake circuit 186 includes one or more intake conduits 190 extending between an air intake section 192 and the intake manifold 184, thereby supplying air to the piston engine 18. The air intake section 192 may include, for example, an air intake duct, air filter, or other features for processing the air entering the intake system 188.

[0021] The exhaust system 22 has one or more exhaust conduits 32 extending between an exhaust section 194 and the exhaust manifold 182. The exhaust section 194 may include, for example, a muffler, a treatment 197 (e.g., a three-way catalyst), a diversion duct, or other features that facilitate the discharge of exhaust gases to the atmosphere. As mentioned above, the exhaust system 22 may also include one or more EGR circuits 34 (e.g., the recirculation conduit 14) to facilitate exhaust gas recirculation between the exhaust circuit 28 and the intake circuit 186. For example, the EGR circuits 34 may include EGR lines 199 disposed upstream and / or downstream of a turbocharger 195, which includes a turbine 196 disposed along the exhaust line 32, a compressor 198 disposed along the intake line 190, and a shaft 200 coupling the turbine 196 and the compressor 198 together.The turbocharger 195 is driven by exhaust gas passed through the exhaust conduit 32 and through the turbine 196, which in turn rotates the shaft 200 coupled to the compressor 198. The compressor 198 operates to compress an airflow from the air intake section 192, which flows along the intake conduit 190 into the intake manifold 184.

[0022] As mentioned above, the EGR circuits 34 may include EGR lines 199 both upstream and downstream of the turbocharger 195. For example, the EGR circuits 34 may include EGR circuits 202 and 204 located at different upstream and downstream positions relative to the turbocharger 195. In the illustrated embodiment, the EGR circuit 202 includes EGR lines 206 and 208 coupled to the respective exhaust line 32 and the intake line 190, with the EGR lines 206 and 208 also coupling to one of the heat exchanger assemblies 36 (e.g., the heat exchanger assembly 40). Similarly, the EGR circuit 204 has EGR lines 210 and 212 coupled to the respective exhaust line 32 and the intake line 190, with the EGR lines 210 and 212 also coupling to one of the heat exchanger assemblies 36 (e.g., the heat exchanger assembly 42).In the illustrated embodiment, EGR circuit 202 may be described as a high-pressure EGR circuit due to its location upstream of turbine 196, while EGR circuit 204 may be considered a low-pressure EGR circuit based on its location downstream of turbine 196. Exhaust system 22 may include one or more of the heat recovery systems, such as exhaust waste heat recovery system 106 with one of the heat exchanger assemblies 36 (e.g., heat exchanger assembly 44).

[0023] The combustion system 10 may include a variety of components along the exhaust system 22 and the intake system 188. As described above, the turbine 196 of the turbocharger 195 is disposed along the exhaust conduit 32 of the exhaust system 22. The turbocharger 195 may also include a bypass valve or waste gate 214 configured to open and close to vary a bypass of the exhaust gas around the turbine 196. The exhaust section 194 may also include various components, such as the muffler, the treatment 197, or other exhaust treatment components.

[0024] Similarly, the intake system 188 may include a bypass valve 216 configured to open and close to vary a bypass flow of intake air around the compressor 198. The intake circuit 186 of the intake system 188 may include an intercooler 218 configured to regulate the temperature of the intake air, and a throttle 220 configured to control the flow of intake air and fuel 221 from a fuel supply 223 into the intake manifold 184. The intercooler 218 may, for example, be a heat exchanger configured to remove heat from the intake air after compression in the compressor 198, thereby cooling the compressed air to a suitable temperature before it is drawn into the piston engine 18 via the intake manifold 184. The throttle 220 may also be configured to restrict the fluid flows (e.g.Air, exhaust gas recirculation, and fuel) into the intake manifold 184 downstream of the intercooler 218. The air intake section 192 may include air filters, intake ducts, or other equipment, as described above, to properly draw in and direct the airflow into the piston engine 18.

[0025] Each of the EGR circuits 202 and 204 may be configured such that exhaust gas 30 diverted along the exhaust conduit 32 is recirculated into the intake conduit 190 to return to the intake manifold 184 of the reciprocating engine 18. Each of the EGR circuits 202 and 204 includes an EGR valve, such as EGR valves 222 and 224, configured to regulate the flow of the exhaust gas 30 back into the reciprocating engine 18 through the respective circuits 202 and 204. Downstream of the EGR valves, the EGR circuits 202 and 204 may include an EGR mixer, such as EGR mixers 226 and 228. The EGR mixers 226 and 228 are configured to mix the EGR flow (e.g., the exhaust gas) with the air flowing in from the air intake section 192. The EGR mixers 226 and 228 mix the exhaust gas and the air before they are directed into the piston engine 18 via the intake manifold 184.The EGR mixer 226 mixes the exhaust gas and the air downstream of the compressor 198 of the turbocharger 195, while the EGR mixer 228 mixes the exhaust gas into the air upstream of the compressor 198 of the turbocharger 195.

[0026] In certain embodiments, the combustion system 10 may include only one or both of the EGR circuits 202 and 204 and the respective heat exchanger assemblies 36. Each of the heat exchanger assemblies 36, such as the heat exchanger assemblies 40 and 42, may be configured to transfer heat away from the exhaust gas 30 and into one or more heat exchange fluids 142 of a heat exchange fluid system 229. As previously mentioned, the heat exchange fluids 142 may include, for example, a main engine fluid and / or an auxiliary fluid. The heat exchanger assemblies 36 transfer heat from the exhaust gas into the heat exchange fluids 142 of the heat exchange fluid system 229, thereby cooling the exhaust gas before it is recirculated to the intake manifold 184 of the reciprocating engine 18.The heat exchange fluid system 229 may include one or more components 242, such as components 244, 246, 248, and 250, such as fluid pumps, valves, filters, sensors, or any combination thereof. The heat exchanger assemblies 36 (e.g., heat exchanger assemblies 40 and 42) may be described as EGR cooling systems, such as multi-stage EGR cooling systems that provide EGR cooling in a plurality of stages.

[0027] As explained above, each of the heat exchanger assemblies 36 (e.g., the heat exchanger assemblies 40 and 42) includes a plurality of heat exchanger modules 37, such as heat exchangers 52, 54, 56, and 58, arranged in series and / or parallel along the EGR circuit 202 or 204. The heat exchanger modules 37 are coupled to one of the manifolds 38, which in turn couples to the EGR lines 206 and 208 of the EGR circuit 202 or the EGR lines 210 and 212 of the EGR circuit 204. In EGR circuit 202, EGR line 206 directs exhaust gas from exhaust line 32 into manifold 38, while EGR line 208 receives a discharge of exhaust gas from manifold 38 and returns the exhaust gas to intake line 190. In EGR circuit 204, EGR line 210 is coupled to an inlet of manifold 38, while EGR line 212 couples to a discharge of manifold 38 and returns the exhaust gas to intake line 190.Similarly, in the exhaust waste heat recovery system 106, one of the heat exchanger assemblies 36 (e.g., the heat exchanger assembly 44) is coupled to the exhaust section 194 to facilitate waste heat recovery via the heat exchanger modules 37. The heat exchanger assembly 44 of the exhaust waste heat recovery system 106 may include any number of heat exchanger modules 37 in series, parallel, or a combination thereof, similar to the heat exchanger modules 37 in the EGR circuits 202 and 204.

[0028] In each of the heat exchanger assemblies 36, the manifold 38 and the heat exchanger modules 37 may be coupled together and supported by a support system 230. The support system 230 may include, for example, a horizontal support, plate, or table 232, a vertical support or backrest 234, and a plurality of legs 236. The horizontal support 232 may be configured to support the heat exchanger modules 37, the vertical support 234 may be configured to support the manifold 38, and the legs 236 are coupled to the horizontal support 232 and extend to the floor to support the entire support system 230 at a vertical distance above the floor. However, a variety of support systems 230 may be used to support each of the heat exchanger assemblies 36.

[0029] In certain embodiments, the combustion system 10 may include a control system 252 having a controller 254 coupled to a plurality of sensors 256 and actuators 258 distributed throughout the combustion system 10. For example, the sensors 256, labeled "S," may be coupled to the combustion system 10 at various locations along the exhaust system 22, the intake system 188, the EGR circuit 202, the EGR circuit 204, the turbocharger 195, the piston engine 18, and the heat exchanger assemblies 36. Each of these sensors 256 may be configured to receive feedback associated with one or more parameters of an exhaust gas in the exhaust system 22. For example, the sensors 256 may be used to monitor a temperature of the exhaust gas discharged via the exhaust system 22.Additionally or alternatively, sensors 256 may be configured to monitor a parameter indicative of an amount of emissions (e.g., emission gases) in the exhaust gas discharged via exhaust system 22. Actuators 258 may include valve actuators, such as valve actuators for waste gate valve 214 and bypass valve 216, pump actuators for heat exchange fluid system 229, valve actuators for EGR valves 222 and 224, or any combination thereof.

[0030] Sensors 256 monitor the parameters and, in certain embodiments, store them in memory along with other information related to exhaust system 22. Sensors 256 may include physical sensors and / or virtual sensors configured to measure certain parameters based on input data. The monitored parameters may include temperature, pressure, flow rate, leakage, fluid composition, vibration, time, piston engine metrics, or a combination thereof.

[0031] The parameters monitored by sensors 256 may be further characterized as set forth below. At least some or all of the monitored parameters correspond to a measured temperature, a measured pressure, a measured flow rate, or a combination thereof of the exhaust gas flowing through exhaust system 22. The measured temperature may include an exhaust gas temperature, a main fluid temperature, and / or a supplemental fluid temperature, where the respective temperatures may include the temperatures measured at the inlets and outlets, and the temperature changes between the inlets and outlets, of exhaust system 22. For exhaust temperatures, exhaust temperatures may include EGR exhaust temperatures, heat recovery (HR) exhaust temperatures (e.g., in exhaust waste heat recovery system 106), or any combination thereof.Similarly, the measured pressure may include an exhaust pressure, a main fluid pressure, and / or a supplemental fluid pressure, where the respective pressures may include the pressures measured at the inlets and outlets and the pressure changes between the inlets and outlets (e.g., pressure drops) of the exhaust system 22. Similarly, the measured flow rate may include an exhaust flow rate, a main fluid flow rate, and / or a supplemental fluid flow rate, where the respective flow rates may include the flow rates measured at the inlets and outlets and the flow rate changes between the inlets and outlets of the exhaust system 22.

[0032] In certain embodiments, the sensors 256 may be configured to monitor a measured composition of the exhaust gas flowing through the exhaust system 22. The measured composition of the exhaust gas may include, for example, a moisture or condensate content in the exhaust gas, a particulate or soot content in the exhaust gas, a carbon dioxide (CO2) content in the exhaust gas, an oxygen (O2) content in the exhaust gas, a nitrogen oxide (NO x ) content in the exhaust gas, a sulfur oxide (SO x ) content in the exhaust gas or any combination thereof.

[0033] In certain embodiments, the controller 254 may include a processor 260, a memory 262, instructions 264 stored in the memory and executable by the processor, and a communication circuit 266 configured to communicate with the sensors distributed within the combustion system 10. As discussed herein, the controller 254 may be configured to control the condensate injection system 12 to inject the condensate via an injector into each combustion chamber 292 (see Fig. 2) of the reciprocating engine 18 during a portion of the engine cycle of the reciprocating engine 18. In certain embodiments, the controller 254 may be configured to control the condensate injection system 12 in response to the feedback received from the sensors 256. The controller 254 may use local and / or remote computer systems and storage, web-based interfaces, cloud-based interfaces, apps on smart devices (e.g., smartphones, tablet computers, etc.), or any suitable user interface. The controller 254, in certain embodiments, may implement a cloud-based platform used for asset management of the reciprocating engines 18, such as myPlant provided by Innio in Jenbach, Tyrol, Austria.

[0034] Fig. 2 is a schematic representation of one embodiment of a piston-cylinder assembly 280 having one or more injectors 281 coupled to the condensate injection system 12. In certain embodiments, the injector(s) 281 may include direct injectors that may utilize wall-guided direct injection, air-guided direct injection, spray-guided direct injection, or a combination thereof. As shown, the piston-cylinder assembly 280 includes a piston 174 disposed within a cylinder 176 (e.g., an engine cylinder) of the engine system. The piston 174 is attached to a crankshaft 286 via a connecting rod 288 and a pin 290. The crankshaft 286 converts the linear reciprocating motion of the piston 174 into rotational motion. When the piston 174 moves, the crankshaft 286 rotates to apply the load 180 (in Fig. 1) as described herein. As shown, a combustion chamber 292 is located adjacent the upper fire land 294 of the piston 174. The condensate injection system 12 injects condensate into the combustion chamber 292 via injector(s) 281. In certain embodiments, the injector(s) 281 may additionally inject fuel into the combustion chamber 292 of the piston 174. Alternatively, one or more injectors 281 may be used to inject fuel into the combustion chamber 292, and a separate injector(s) 281 may be used to inject condensate into the combustion chamber 292. In certain embodiments, a separate fuel injection system 293 may inject fuel into the combustion chamber 292 via fuel injector(s) 295. As shown, the fuel injection system 293 may be controlled via the controller 254.During operation, the combustion of the fuel with the air in the combustion chamber 292 causes the piston 174 to reciprocate (e.g., back and forth) in the axial direction 296 within the cylinder 176. During operation, when the piston 174 is at its highest point within the cylinder 176, it is in a position referred to as top dead center (TDC). When the piston 174 is at its lowest point within the cylinder 176, it is in a position referred to as bottom dead center (BDC). In a four-stroke engine, the piston 174 is at top dead center (TDC) twice and bottom dead center (BDC) twice during the four-stroke cycle. The two TDC positions include top dead center ignition (TDCF) and top dead center gas exchange (TDCGE), or top dead center exchange (or alternatively: TDCE).As the piston 174 moves from top to bottom or from bottom to top, the crankshaft 286 rotates half a revolution. Each movement of the piston 174 from top to bottom or from bottom to top is called a stroke.

[0035] As shown, the controller 254 is communicatively coupled to the condensate injection system 12 and configured to control the condensate injection system 12, which is coupled to the injector(s) 281. The controller 254 may be configured to control the condensate injection system 12 to inject the condensate via the injector(s) 281 into a combustion chamber 292 of the reciprocating engine 18 during a portion of the engine cycle of the reciprocating engine 18. The portion of the engine cycle is described in further detail herein.

[0036] Fig. 3 is a diagram of an embodiment of the combustion system 10 of Fig. 1, which further illustrates the condensate injection system 12 coupled to the recirculation line 14 (e.g., EGR circuits 202, 204, and 320) and the reciprocating engine 18 of the combustion system 10. As shown, the condensate injection system 12 includes a condensate tank 322 configured to collect and store condensate from the recirculation line 14. The condensate injection system 12 also includes a pump 324 (e.g., an electric motor-driven pump) coupled to the condensate tank 322. In certain embodiments, the condensate injection system 12 may include a condensate treatment system 326 disposed between the condensate tank 322 and the pump 324, and in certain embodiments, the condensate treatment system 326 may include one or more filters 328.The filters 328 may include, for example, a media filter, a centrifugal separator, a gravity separator, or any combination thereof. The condensate treatment system 326 may also include other treatment systems, such as a biological treatment system (e.g., an ultraviolet light treatment system). In certain embodiments, the condensate treatment system 326 includes a reverse osmosis (RO) system, a deionized water (DI) system, a distilled water system, and / or a pH balancing / neutralization system. The condensate injection system 12 also includes one or more injectors 281 coupled to one or more cylinders and fluidly coupled to the pump 324 of the reciprocating engine 18, and configured to inject condensate (e.g., and fuel) into one or more combustion chambers during a portion of the engine cycle of the reciprocating engine 18.In certain embodiments, each injector 281 may include a common injection flow path for selectively injecting the condensate and fuel at different times, or separate injection flow paths (e.g., coaxial or parallel offset flow paths) for separately injecting the condensate and fuel at different times. Each injector 281 may include one or more liquid injection ports, nozzles, or atomizers for injecting a spray (e.g., an atomized spray) of the condensate or fuel. In certain embodiments, the fuel may be injected into the reciprocating engine 18 via the fuel injection system 293.In certain embodiments, the condensate injection system 12 may include a check valve 321 disposed between the pump 324 and the injector(s) 281 to prevent backflow should the injector(s) open when the cylinder pressure exceeds the condensate pump pressure. In certain embodiments, the condensate injection system 12 may include a pressure relief valve 323 that returns to the condensate reservoir as a way to relieve excess pressure in the condensate fluid circuit 325 if the injector(s) 281 fail to open.

[0037] For condensate injection via injector 282, the portion of the engine cycle includes at least a portion of the combustion stroke (e.g., the power stroke) and / or an exhaust stroke of the engine cycle. In certain embodiments, the combustion stroke extends from TDCF to 180 degrees past TDCF (e.g., a TDCF). Additionally, in certain embodiments, the exhaust stroke extends from 180 degrees past TDCF to TDCGE ​​(or alternatively, TDCE).

[0038] As illustrated, the recirculation line 14 may include the heat exchanger assembly 36 (e.g., exhaust gas cooling system or EGR cooling system) having heat exchanger modules 37 (e.g., heat exchangers 52, 54, 56, and 58) configured to cool the exhaust gas 30. In certain embodiments, the condensate tank 322 may be coupled to one or more of the heat exchanger modules 37 (e.g., condensing heat exchangers), with the heat exchanger modules 37 configured to condense water vapor in the exhaust gas 30 and discharge condensate to the condensate tank 322. In certain embodiments, the heat exchanger modules 37 of the heat exchanger assembly 36 may include one or more non-condensing heat exchangers, one or more condensing heat exchangers, and / or one or more reheat heat exchangers arranged in a sequence (e.g., multi-stage).For example, heat exchangers 52 and 54 may be non-condensing heat exchangers (e.g., first EGR cooler stage), heat exchanger 56 may be a condensing heat exchanger, and heat exchanger 58 may be a reheat heat exchanger. However, any arrangement of non-condensing, condensing, and / or reheat heat exchanger modules 37 may be used for heat exchangers 52, 54, 56, and 58. In certain embodiments, condensate tank 322 may be coupled to one or more condensing heat exchangers via an outlet (e.g., condensate drain line 329) disposed in each of the condensing heat exchangers. Additionally or alternatively, a valve 330 may be disposed between the heat exchanger assembly 36 and the condensate tank 322 and configured to regulate the amount of condensate collected in the condensate tank 322. A condensate liquid circuit (e.g.,a condensate flow path) 325 from the heat exchanger assembly 36 to the injectors 281 of the reciprocating engine 18, the condensate fluid circuit 325 including the valve 330, the condensate reservoir 322, the condensate treatment system 326, the pump 324, and various connecting fluid lines. Although the illustrated embodiment shows condensate collected from the heat exchanger assembly 36, it should be understood that the condensate may additionally or alternatively be collected at other locations, including the location shown in FIG. Fig. 1 shown waste heat recovery system 106.

[0039] As discussed herein, the heat exchanger assembly 36 may be coupled to the reciprocating engine 18. For example, the heat exchanger assembly 36 may be coupled to the intake circuit 186 and the exhaust circuit 28. As illustrated, the recirculation conduit 14 may include EGR circuits 202, 204, or 320. As discussed herein, the EGR circuit 202 may couple to the intake circuit 186 downstream of the compressor 198 and also to the exhaust circuit 28 upstream of the turbine 196. The EGR circuit 204 may couple to the intake circuit 186 upstream of the compressor 198 and also to the exhaust circuit 28 downstream of the turbine 196. The EGR circuit 320 may couple to the intake circuit 186 upstream of the compressor 198, and also to the exhaust circuit 28 upstream of the turbine 196.

[0040] In the illustrated embodiment, the combustion system 10 includes a sensor 256 (e.g., a level sensor 332) coupled to the condensate tank 322. The sensor 332 (e.g., photodetector, float switch, proximity sensor, camera) can be configured to send a signal to the controller 254 indicating an amount of condensate in the condensate tank 322. For example, the sensor 332 can be configured to send the signal to the controller 254 based on the condensate in the condensate tank 322 falling below a threshold (e.g., threshold amount). In certain embodiments, the controller 254 can be configured to control the condensate injection system 12 based on receiving the signal from the sensor 332.For example, controller 254 may be configured to control heat exchanger assembly 36, pump 324, valve 330, injector(s) 281, or a combination thereof based on the signal received from sensor 332. In certain embodiments, controller 254 may be configured to reduce the flow rate of pump 324 and / or a parameter associated with injector(s) 281 (e.g., controlling the amount of condensate injected into piston engine 18, injection duration) based on sensor 332 indicating that the amount of condensate in condensate reservoir 322 is below a threshold. For example, the controller 254 may be configured to adjust a ratio of a first time period during which the injector(s) 281 inject(s) condensate to a second time period during which the injector(s) do not inject condensate.

[0041] In certain embodiments, controller 254 may be configured to control condensate injection (e.g., via injector(s) 281) and / or heat exchanger assembly 36 to maintain a substantially constant condensate level (e.g., within upper and lower thresholds) in condensate reservoir 322. For example, controller 254 may be configured to increase the rate of condensate injected into the cylinder via injector(s) 281 based on an amount of condensate in condensate reservoir 322 exceeding a threshold amount (e.g., a high threshold). Additionally or alternatively, the controller 254 may be configured to reduce a rate of condensate injected into the cylinder via the injector(s) 281 based on an amount of condensate in the condensate reservoir 322 falling below a threshold amount (e.g., a low threshold).In certain embodiments, the controller 254 may be configured to adjust a temperature of the heat exchanger assembly 36 and / or a condensate collection rate in the condensate tank 322 of the heat exchanger modules 37. In certain embodiments, the controller 254 may be configured to adjust the drainage rate of excess condensate to an external drainage system. For example, in response to the amount of condensate in the condensate tank 322 exceeding a threshold (e.g., a high threshold), the controller 254 may be configured to divert the condensate collected by the heat exchanger assembly 36 to the external drainage system.

[0042] In the illustrated embodiment, the combustion system 10 includes a sensor 256 (e.g., sensor 334) coupled to the exhaust system 22. In certain embodiments, the controller 254 may be configured to determine a temperature of the exhaust gas in the exhaust system 22 based on a signal received from the sensor 334. In certain embodiments, the sensor 334 may include a plurality of sensors disposed in the aftertreatment 197 of the exhaust section 194, an inlet of the turbine 196, a cylinder head exhaust port of a cylinder 176 of the engine 18, or a combination thereof (see Fig. 1). The control system 254 may be configured to control condensate injection based on the specified temperature of the exhaust gas in the exhaust system 22. For example, the controller 254 may be configured to reduce an amount of condensate (e.g., via the injector(s) 281) injected into the combustion chamber based on the specified temperature of the exhaust gas falling below a threshold temperature (e.g., a low threshold). Additionally or alternatively, the controller 254 may be configured to inject an amount of condensate (e.g., via the injector(s) 281) into the combustion chamber based on the specified temperature of the exhaust gas exceeding a threshold temperature (e.g., a high threshold).

[0043] In certain embodiments, the combustion system 10 includes a sensor 256 (e.g., sensor 336) coupled to the combustion system 10 upstream of the turbine 196 near an inlet of the turbine 196. In certain embodiments, the controller 254 may be configured to determine a temperature of the inlet of the turbine 196 based on a signal received from the sensor 336. The control system 254 may be configured to control condensate injection based on the determined temperature of the inlet of the turbine 196. For example, the controller 254 may be configured to decrease an amount of condensate injected into the combustion chamber (e.g., via the injector(s) 281) based on the determined temperature of the inlet of the turbine 196 falling below a threshold temperature (e.g., low threshold).Additionally or alternatively, the controller 254 may be configured to increase an amount of condensate (e.g., via the injector(s) 281) injected into the combustion chamber based on the set temperature of the inlet of the turbine 196 exceeding a threshold temperature (e.g., a high threshold).

[0044] In certain embodiments, the combustion system 10 includes one or more sensors 256 (e.g., one or more sensors 338) coupled to one or more cylinders 176 of the engine 18. In certain embodiments, one or more sensors 338 may include one or more terminal thermocouples. The one or more terminal thermocouples may be coupled to one or more cylinders 176 of the engine 18 and may be configured to output a signal indicative of a temperature of individual cylinders 176 and / or an average temperature of the cylinders 176. Additionally or alternatively, the one or more sensors 338 may include in-cylinder pressure transducers disposed on one or more of the cylinders 176.The one or more in-cylinder pressure transducers may be configured to output a signal indicative of a pressure of the individual cylinders 176 and / or an average pressure of the cylinders 176. Additionally or alternatively, the one or more sensors 338 may include one or more knock sensors configured to estimate an in-cylinder pressure curve (e.g., pressure reconstruction). The controller 254 may be configured to determine a temperature and / or pressure of one or more cylinders 176 of the engine 18 based on receiving the signal from one or more sensors 338. The control system 254 may be configured to control condensate injection based on the determined temperature and / or pressure of the one or more cylinders 176. For example, the controller 254 may be configured to determine an amount of condensate (e.g.,via injector(s) 281) injected into the combustion chamber is reduced based on the specified temperature and / or pressure of the one or more cylinders 176 falling below a threshold temperature and / or pressure (e.g., a low threshold). Additionally or alternatively, controller 254 may be configured to increase an amount of condensate (e.g., via injector(s) 281) injected into the combustion chamber based on the specified temperature and / or pressure of the one or more cylinders 176 exceeding a threshold (e.g., a high threshold) for temperature and / or pressure.

[0045] In certain embodiments, the combustion system 10 may include one or more sensors 256 (e.g., one or more sensors 340) disposed between the pump 324 and the engine 18. The one or more sensors 340 may include one or more pressure sensors configured to measure an outlet pressure of the condensate in the fluid circuit 325 prior to injection of the condensate into the engine 18. The controller 254 may be configured to determine a pressure of the condensate disposed between the pump 324 and the engine 18 based on receiving the signal from the one or more sensors 340. The control system 254 may be configured to control the condensate injection based on the determined condensate pressure. For example, the controller 254 may be configured to determine an amount of condensate injected into the combustion chamber (e.g.,via the injector(s) 281) is reduced based on the specified condensate pressure falling below a threshold pressure (e.g., low threshold). Additionally or alternatively, the controller 254 may be configured to increase an amount of condensate (e.g., via the injector(s) 281) injected into the combustion chamber based on the specified pressure of the condensate exceeding a threshold pressure (e.g., a high threshold).

[0046] Fig. 4 is an embodiment of a graph 350 illustrating an internal pressure 352 and a crank angle 354 of a four-stroke engine cycle 356 of the piston-cylinder assembly 280 of Fig. 2. As illustrated, the four-stroke engine cycle 356 includes a compression stroke 358 (e.g., compression stage), a power stroke 360 ​​(e.g., power stage, combustion stroke, combustion stage), an exhaust stroke 362 (e.g., exhaust stage), and an intake stroke 364 (e.g., intake stage). The crank angle 354 ranges from -180 degrees (e.g., at the beginning of the compression stroke 358) to 540 degrees (e.g., at the end of the intake stroke 364). As illustrated, the internal pressure 352 of a cylinder of the piston engine peaks between the end of the compression stroke 358 and the beginning of the power stroke 360. In the illustrated embodiment, the TDCF of the four-stroke cycle is at 0 degrees crank angle, and the TDCGE ​​(or alternatively TDCE) of the four-stroke cycle is at 360 degrees crank angle.

[0047] In certain embodiments, the controller 254 may be configured to instruct the condensate injection system 12 to inject condensate in one or more intervals 363 during a portion 365 (e.g., a condensate injection window, a condensate injection limit, or a condensate injection spectrum) of the four-stroke engine cycle 356 at least partially or entirely during the power stroke 360 ​​and / or the exhaust stroke 362. In certain embodiments, the portion 365 may be described as a maximum allowable window (e.g., crank angle window) suitable for condensate injection, while condensate injection may occur in one or more intervals 363 during all or part of the maximum allowable window.As shown in the illustrated embodiment, the portion 365 of the four-stroke engine cycle 356, during which the condensate injection system 12 may be configured to inject condensate into the combustion chamber 292 of the piston-cylinder assembly 280 of the piston engine 18, may occur between a first point 366 (e.g., a first boundary or limit) and a second point 368 (e.g., second boundary or limit) along the four-stroke engine cycle 356. In the illustrated embodiment, the portion 365 of the four-stroke engine cycle 356 includes portions 370 and 372 of the four-stroke engine cycle 356, with portion 370 occurring during the power stroke 360 ​​and portion 372 occurring during the exhaust stroke 362. For example, portion 370 may be an end portion of power stroke 360, and portion 372 may be all or part of exhaust stroke 362.Accordingly, in the illustrated embodiment, portion 370 extends from the first point 366 during the power stroke 360 ​​to a transition point 367 between the power stroke 360 ​​and the exhaust stroke 362, while portion 372 extends from the transition point 367 to the second point 368. In certain embodiments, the second point 368 may be a transition point between the exhaust stroke 362 and the intake stroke 364, or the second point 368 may be prior to the transition point during the exhaust stroke 362.

[0048] In certain embodiments, the first point 366 may be defined by an offset from an end-of-combustion point (EOC) defined by (MFB) according to the Rassweiler and Withrow method. In certain embodiments, the MFB may be between 0 and 1 and described as a Wiebe function curve based on initial pressure and volume (e.g., at ignition), final pressure and volume (e.g., at the end of combustion), a polytropic index relating cylinder pressure and volume, and pressure and volume during combustion. In certain embodiments, the EOC is defined as at least 80, 85, 90, or 95 percent of the MFB. In certain embodiments, the second point 368 may be during a final portion of the exhaust stroke 362. For example, the second point 368 may occur before an intake valve opening 363 (IVO) of a cylinder of the engine opens.The IVO can be as early as 30 degrees of crank angle before the TDCGE ​​(or alternatively TDCE).

[0049] The portion 365 of the four-stroke engine cycle 356 bounded by the first and second points 366 and 368 defines an acceptable window for condensate injection during which the controller 254 may command the condensate injection system 12 to inject the condensate for the one or more intervals 363. In certain embodiments, the one or more intervals 363 may include a single interval 363A spanning all or a portion of the portion 365, or a plurality of intervals 363 (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, or more intervals) spanning all or a portion of the portion 365. The one or more intervals 363 (e.g., 363A and 363B) may begin directly at or after the first point 366 during the power stroke 360 ​​or the exhaust stroke 362, and the one or more intervals 363 (e.g.,363A and 363B) may end directly at or before the second point 368 during the power stroke 360 ​​or the exhaust stroke 362. In addition, the controller 254 may instruct the condensate injection system 12 to vary the number and duration of the intervals 363 (e.g., 363A and 363B), the starting point of the intervals 363, the end point of the interval, or any combination thereof, depending on the exhaust temperature 30, the amount of available condensate, the exhaust emissions, the fuel composition, the combustion parameters, or any combination thereof.

[0050] In certain embodiments, portion 370 of power stroke 360 ​​includes a first crank angle window 374 from the crank angle 354 at the first point 366 before an end 376 of power stroke 360 ​​(e.g., transition point 367) to the crank angle 354 at the end 376 of power stroke 360. In certain embodiments, the first crank angle window 374 may be equal to, less than, or greater than at least 5, 10, 15, or 20 degrees. Similarly, the crank angle 354 at the first point 366 before the end 376 of power stroke 360 ​​may be equal to, less than, or greater than at least 5, 10, 15, or 20 degrees. The portion 372 of the exhaust stroke 362 includes a second crank angle window 378 that extends from the crank angle 354 at the end 376 of the power stroke 360 ​​(e.g., transition point 367) to the crank angle 354 at the second point 368. As described above, the crank angle 354 of the second point 368 may be directly at or before an end 380 of the exhaust stroke 362 (e.g.,at the transition point between the exhaust stroke 362 and the intake stroke 364). For example, the crank angle 354 of the second point 368 may be equal to, less than, or greater than at least 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, or 90 degrees before the end 380 of the exhaust stroke 362. Thus, the second crank angle window 378 may be a remaining range of crank angles between the end 376 of the expansion stroke 360 ​​and the second point 368, such as equal to, less than, or greater than at least 270, 280, 290, 300, 310, 320, 330, 340, 350, or 355 degrees. For example, in certain embodiments, the portion 365 of the four-stroke engine cycle 356 available for condensate injection may include at least 50, 60, 70, 80, 90, 95, 99, or 100 percent of the exhaust stroke 362, and less than 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 percent of the power stroke 360 ​​(e.g., immediately before the end 376 of the power stroke 360).For example, in certain embodiments, the portion 365 of the four-stroke engine cycle 356 available for condensate injection may include approximately 50 to 100, 60 to 100, 70 to 100, 80 to 100, or 90 to 100 percent of the exhaust stroke 362, and 0 to 50, 0 to 40, 0 to 30, 0 to 20, or 0 to 10 percent of the power stroke 360. In certain embodiments, the portion 365 may exclude the intake stroke 364 and the compression stroke 358 such that condensate injection does not occur during the intake stroke 364 and the compression stroke 358.As mentioned above, the first and second crank angle windows 374 and 378 define the portion 365 available for condensate injection relative to the crank angle 354, with the controller 254 configured to inject condensate into the combustion chamber 292 at one or more intervals 363 during all or a portion of the first and / or second crank angle windows 374 and 378. Thus, the one or more intervals 363 (e.g., 363A and 363B) may be defined based on the crank angle 354. In certain embodiments, each of the one or more intervals 363 (e.g., 363A and 363B) of condensate injection may occur over a change in crank angle 354 of equal to, less than, or greater than at least 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200 degrees.

[0051] Portions 365, 370, and 372 may also be described relative to TDCF and TDCGE. As illustrated, the first point 366 is between TDCF and a transition point 367 occurring 180 degrees after aTDCF. In certain embodiments, the first point 366 may have a crank angle 354 that is equal to, less than, or greater than at least 160, 165, 170, or 175 degrees aTDCF. Portion 372 of the exhaust stroke 362 includes a second crank angle window 378 that extends from the crank angle 354 at the transition point 367 to a second point 368 located at TDCGE ​​(or alternatively, TDCE). In certain embodiments, the second point 368 may be equal to, less than, or greater than at least 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, or 90 degrees before TDCGE ​​(e.g., bTDCGE). Thus, the second crank angle window 378 may be a remaining range of crank angles between the transition point 367 and the second point 368.In certain embodiments, the second point 368 may be located at at least 270, 280, 290, 300, 310, 320, 330, 340, 350, or 355 degrees aTDCF. In certain embodiments, the portion 365 may exclude the intake stroke 364 and the compression stroke 358 such that condensate injection does not occur during the intake stroke 364 and the compression stroke 358. That is, the portion 365 may exclude crank angles 354 that occur between 360 degrees and 540 degrees aTDCF and between TDCF and 180 degrees before TDCF (e.g., bTDCF).

[0052] In certain embodiments, combustion system 10 may include a fuel injection system coupled to or located near injector 281. Controller 254 may be configured to control the fuel injection system to inject a fuel (e.g., hydrocarbon-based fuel, hydrogen, etc.) through injector 281 into combustion chamber 292 at an appropriate fuel injection time during an additional portion of four-stroke engine cycle 356 (e.g., during intake stroke 364). In certain embodiments, the additional portion of four-stroke engine cycle 356 during which fuel is injected into combustion chamber 292 and portion 365 of four-stroke engine cycle 356 during which condensate is injected into combustion chamber 292 are different from each other.In certain embodiments, controller 254 is configured to control condensate injection system 12 to inject condensate to suppress post-combustion reactions and reduce undesirable emissions (e.g., CO, NOx, SOx, etc.). The method for determining the time at which condensate is injected into combustion chamber 292 is described in detail below.

[0053] Fig. 5 is a flowchart illustrating one embodiment of a process 400 for controlling the condensate injection system 12 of Fig. 2. In block 402 of process 400, the controller 254 may be configured to monitor an exhaust gas temperature of a reciprocating engine. For example, the controller 254 may be configured to receive a signal (e.g., feedback) from a sensor (e.g., thermocouple, resistance temperature detector [RTD], etc.) configured to provide a signal indicative of an exhaust gas temperature in the exhaust system of the combustion system. Additionally, the controller 254 may be configured to determine whether the monitored exhaust gas temperature decreases below a low threshold temperature and / or increases above a high threshold temperature.

[0054] At block 404, the controller 254 may be configured to monitor an amount of condensate stored in the condensate reservoir of the condensate injection system coupled to the piston engine. For example, the controller 254 may be configured to receive a signal (e.g., feedback) from a sensor (e.g., a resistive fuel sensor / float fuel sensor, a capacitive fuel sensor, etc.) configured to determine an amount (e.g., level) of condensate stored in the condensate reservoir. Additionally, the controller 254 may be configured to determine whether the condensate in the condensate reservoir decreases below a low threshold amount. Additionally or alternatively, the controller 254 may be configured to determine whether the condensate in the condensate reservoir increases above a high threshold amount of condensate.

[0055] At block 406, the controller 254 may be configured to monitor one or more operating parameters of the reciprocating engine. For example, a position sensor (e.g., magnetic pickup or Hall effect) may be coupled to the crankshaft of the reciprocating engine and configured to send a signal (e.g., feedback) indicative of a crank angle to the controller 254. In response to receiving the signal, the controller 254 may be configured to determine a crank angle of the crankshaft of the reciprocating engine.

[0056] At block 408, the controller 254 may be configured to evaluate the one or more parameters within performance maps (e.g., lookup tables) associated with the piston engine. For example, the controller 254 may be configured to use the performance maps in conjunction with one or more known parameters (e.g., fuel index, intake manifold absolute pressure, engine speed, spark timing, etc.) to provide parameters that are not directly measured (e.g., internal combustion chamber pressure). In certain embodiments, performance maps may be used for standard and non-standard conditions (e.g., less than commercial grade natural gas, less than full engine speed, etc.). For example, non-standard conditions may be approximated by means of a corresponding deviation from the standard conditions.

[0057] At block 410, the controller 254 may be configured to determine, based on the evaluation of the one or more parameters, a threshold pressure for injecting condensate into a cylinder of the piston engine. For example, the controller 254 may be configured to determine the threshold pressure by setting the threshold pressure to be lower than the pressure at which the condensate is injected into the combustion chamber of the cylinder.

[0058] In block 412, the controller 254 may be configured to determine a crank angle for injecting the condensate based on the threshold pressure. For example, the controller 254 may be configured to display a graph similar to that shown in Fig.4, which maps the internal pressure of the combustion chamber to the crankshaft angle. For example, the controller 254 may be configured to determine the starting point of the portion of the engine cycle during which condensate is injected into the combustion chamber based on the specified threshold internal pressure of the combustion chamber.

[0059] At block 414, the controller 254 may be configured to monitor and / or control the heat exchanger assembly (e.g., the EGR cooler system) of the reciprocating engine to collect the condensate in the condensate tank. In certain embodiments, the controller 254 may be configured to adjust the amount of condensate produced by the heat exchanger assembly such that the amount of condensate stored in the condensate tank remains between a low threshold amount and a high threshold amount. For example, the controller 254 may be configured to increase the temperature of the heat exchanger assembly (e.g., decrease condensate production) based on the amount of condensate in the condensate tank exceeding a high threshold. Additionally or alternatively, the controller 254 may be configured to decrease the temperature of the heat exchanger assembly (e.g.,increases condensate production) based on the amount of condensate in the condensate tank falling below a low threshold. In certain embodiments, the controller 254 may be configured to control the amount of condensate produced by the heat exchanger assembly by controlling a temperature of the heat exchanger assembly.

[0060] At block 416, the controller 254 may be configured to control the condensate injection system based on the monitored temperature, crank angle, and the amount of condensate in the condensate tank. For example, the controller 254 may be configured to control a flow rate, pressure, injection configuration, or a combination thereof based on the monitored exhaust gas temperature, crank angle, the amount of condensate in the condensate tank, or any combination thereof.

[0061] The technical effects of the disclosed embodiments include the use of condensate (e.g., water) collected in the EGR system to regulate the cylinder head exhaust port temperature and / or turbine inlet temperature associated with combustion. For example, a controller may be configured to monitor an exhaust gas temperature located in an exhaust system of the combustion system. If the temperature of the exhaust gas decreases below a lower threshold or increases above a higher threshold, the controller may be configured to decrease or increase, respectively, the amount of condensate (e.g., collected from the EGR) into the combustion chamber. By controlling the amount of condensate injected into the combustion cylinder based on the exhaust gas temperature, the controller may be configured to regulate the exhaust gas temperature between the lower and upper temperature thresholds.In addition, the exhaust gas mass flow to the turbine is increased by injecting condensate.

[0062] The subject matter described in detail above may be defined by one or more clauses as set out below.

[0063] A system includes a condensate injection system configured to be fluidly coupled to a combustion chamber of a piston engine and an exhaust gas recirculation (EGR) system of the piston engine. The condensate injection system includes a condensate reservoir configured to store condensate collected by the EGR system. The condensate injection system also includes a pump fluidly coupled to the condensate reservoir. The condensate injection system also includes an injector fluidly coupled to the pump. The injector is configured to inject condensate into the combustion chamber during a first portion of an engine cycle of the piston engine. The first portion of the engine cycle includes at least a portion of a power stroke and / or an exhaust stroke of the engine cycle.

[0064] The system of the preceding paragraph comprising the piston engine, wherein the engine cycle comprises a four-stroke engine cycle including an intake stroke, a compression stroke, the power stroke, and the exhaust stroke.

[0065] The system and any preceding paragraph which includes the EGR system coupled to the piston engine.

[0066] The system according to any preceding paragraph, wherein the EGR system comprises an exhaust gas cooling system having a plurality of EGR coolers configured to cool an exhaust gas recirculated from an exhaust manifold to an intake manifold of the reciprocating engine, wherein a condensate drain line is coupled to the exhaust gas cooling system and the condensate tank.

[0067] The system of any preceding paragraph, comprising a controller having a processor, a memory, and instructions stored in the memory and executable by the processor to control the condensate injection system to inject the condensate through the injector into the combustion chamber during the first portion of the engine cycle.

[0068] The system of the preceding paragraph, wherein the condensate injection system comprises a condensate treatment system comprising a reverse osmosis system, a deionized system, a distilled water system, a pH balancing system, or a combination thereof; a check valve disposed between the injector and the pump; a pressure relief valve; or a combination thereof.

[0069] The system of any preceding paragraph, comprising one or more sensors configured to receive feedback related to one or more parameters of an exhaust gas, wherein the controller is configured to control the condensate injection system to inject the condensate in response to the feedback.

[0070] The system of any preceding paragraph, comprising a fuel injector coupled to the injector, wherein the controller is configured to control the fuel injection such that a fuel is injected into the combustion chamber by the injector during a second portion of the engine cycle, and the first and second portions of the engine cycle are different from each other.

[0071] The system according to any preceding paragraph, wherein the first portion of the engine cycle excludes an intake stage and a compression stage.

[0072] The system of any preceding paragraph, wherein the injector is configured to inject the condensate into the combustion chamber at one or more intervals during all or a portion of the first portion of the engine cycle, the first portion comprising a terminal portion of the power stroke and all or a portion of the exhaust stroke between the first and second points along the engine cycle.

[0073] The system of any preceding paragraph, wherein the first portion comprises a crank angle window, the end portion comprises a first crank angle window from a first crank angle at least 20 degrees before a first end of the power stroke to a second crank angle at the first end of the power stroke, and the second end portion comprises a second crank angle window from a third crank angle at the first end of the power stroke to a fourth crank angle at or before a second end of the exhaust stroke.

[0074] A system includes a controller having a processor, a memory, and instructions stored in the memory and executable by the processor to control a condensate injection system configured to be fluidly coupled to a combustion chamber of a piston engine and an exhaust gas recirculation (EGR) system of the piston engine. The condensate injection system includes a condensate reservoir configured to store condensate collected by the EGR system, a pump fluidly coupled to the condensate reservoir, and an injector fluidly coupled to the pump. The controller is configured to control the injector to inject condensate into the combustion chamber during a first portion of an engine cycle of the piston engine. The first portion of the engine cycle includes at least a portion of a power stroke and / or an exhaust stroke of the engine cycle.

[0075] The system of the preceding paragraph, wherein the controller is configured to receive first feedback from a first sensor indicative of exhaust gas temperature located in an exhaust system of the piston engine. The controller is also configured to control the condensate injection system based on the first feedback.

[0076] The system of any preceding paragraph, wherein controlling the condensate injection system comprises decreasing an amount of condensate injected into the combustion chamber based on the exhaust gas temperature falling below a low threshold, increasing the amount of condensate based on the temperature exceeding a high threshold, or any combination thereof.

[0077] The system of any preceding paragraph, wherein the controller is configured to receive second feedback from a second sensor indicative of an amount of condensate in the condensate reservoir. The controller is also configured to receive third feedback from a third sensor indicative of one or more operating parameters of the reciprocating engine. The controller is also configured to control the condensate injection system based on the first feedback, the second feedback, or any combination thereof.

[0078] A method includes controlling, via a controller, a condensate injection system configured to be fluidly coupled to a combustion chamber of a piston engine and an exhaust gas recirculation (EGR) system of the piston engine. The condensate injection system includes a condensate reservoir configured to store condensate collected by the EGR system, a pump fluidly coupled to the condensate reservoir, and an injector fluidly coupled to the pump. The controller includes controlling the injector to inject the condensate into the combustion chamber during a first portion of an engine cycle of the piston engine. The first portion of the engine cycle includes at least a portion of a power stroke and / or an exhaust stroke of the engine cycle.

[0079] The method of the preceding paragraph, wherein controlling the condensate injection system comprises monitoring an exhaust gas temperature of the piston engine. Controlling the condensate injection system also comprises monitoring an amount of condensate stored in the condensate reservoir of the condensate injection system.

[0080] The method of any preceding paragraph, wherein controlling the condensate injection system comprises evaluating the one or more operating parameters within performance maps of the reciprocating engine, determining a threshold pressure for injecting the condensate into a cylinder of the reciprocating engine based on the evaluation of the one or more operating parameters, and determining a crank angle for injecting the condensate based on the threshold pressure.

[0081] The method of any preceding paragraph, wherein controlling the condensate injection system comprises monitoring the EGR system of the reciprocating engine to collect the condensate in the condensate reservoir, controlling the EGR system of the reciprocating engine to collect the condensate in the condensate reservoir, or a combination thereof.

[0082] The method of any preceding paragraph, wherein controlling the condensate injection system comprises obtaining feedback from a sensor indicative of the amount of condensate in the condensate tank and controlling the amount of condensate in the condensate tank based on the feedback.

[0083] This written description uses examples to disclose the invention and encompasses the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any methods incorporated therein. The patentable scope of the invention 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 include 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.

[0084] The technology presented and claimed herein is directed to and applied to tangible tasks and concrete examples of a practical nature that demonstrably improve the current technical field, and as such, is not abstract, intangible, or purely theoretical. Furthermore, when any claims appended to the end of this specification contain one or more elements characterized as "means for performing a function..." or "step for performing a function...", it is intended that such elements be construed in accordance with 35 USC 112(f). However, for any claims containing elements framed in any other manner, it is intended that such elements not be construed in accordance with 35 USC 112(f).

Claims

[1] A system comprising a condensate injection system configured to be fluidly coupled to a combustion chamber of a piston engine and an exhaust gas recirculation (EGR) system of the piston engine, the condensate injection system comprising: a condensate tank configured to store condensate collected from the EGR system; a pump fluidly coupled to the condensate tank; and an injector fluidly coupled to the pump, the injector configured to inject condensate into the combustion chamber during a first portion of an engine cycle of the reciprocating engine, the first portion of the engine cycle comprising at least a portion of a power stroke and / or an exhaust stroke of the engine cycle. [2] The system of claim 1, comprising the piston engine, wherein the engine cycle comprises a four-stroke engine cycle including an intake stroke, a compression stroke, the power stroke, and the exhaust stroke. [3] The system of claim 2, comprising the EGR system coupled to the piston engine. [4] The system of claim 1, wherein the EGR system comprises an exhaust gas cooling system having a plurality of EGR coolers configured to cool an exhaust gas recirculated from an exhaust manifold to an intake manifold of the reciprocating engine, wherein a condensate drain line is coupled to the exhaust gas cooling system and the condensate reservoir. [5] The system of claim 1, comprising a controller having a processor, a memory, and instructions stored in the memory and executable by the processor to control the condensate injection system to inject the condensate through the injector into the combustion chamber during the first portion of the engine cycle. [6] The system of claim 5, wherein the condensate injection system comprises: a condensate treatment system comprising a reverse osmosis system, a deionized system, a distilled water system, a pH balancing system, or a combination thereof; a check valve arranged between the injector and the pump; a pressure relief valve; or a combination thereof. [7] The system of claim 6, comprising one or more sensors configured to receive feedback related to one or more parameters of an exhaust gas, wherein the controller is configured to control the condensate injection system to inject the condensate in response to the feedback. [8] The system of claim 5, comprising a fuel injection system coupled to the injector, wherein the controller is configured to control the fuel injection system such that fuel is injected into the combustion chamber by the injector during a second portion of the engine cycle, and wherein the first and second portions of the engine cycle are different from each other. [9] The system of claim 1, wherein the first portion of the engine cycle excludes an intake stage and a compression stage. [10] The system of claim 1, wherein the injector is configured to inject the condensate into the combustion chamber at one or more intervals during all or a portion of the first portion of the engine cycle, the first portion comprising a terminal portion of the power stroke, and all or a portion of the exhaust stroke between first and second points along the engine cycle. [11] The system of claim 10, wherein the first portion comprises a crank angle window, the end portion comprises a first crank angle window from a first crank angle at least 20 degrees before a first end of the power stroke to a second crank angle at the first end of the power stroke, and the second end portion comprises a second crank angle window from a third crank angle at the first end of the power stroke to a fourth crank angle at or before a second end of the exhaust stroke. [12] A system comprising: a controller having a processor, a memory, and instructions stored in the memory and executable by the processor to control a condensate injection system configured to be fluidly coupled to a combustion chamber of a reciprocating engine and an exhaust gas recirculation (EGR) system of the reciprocating engine, the condensate injection system including a condensate reservoir configured to store condensate collected from the EGR system, a pump fluidly coupled to the condensate reservoir, and an injector fluidly coupled to the pump, the controller configured to: controls the injector to inject condensate into the combustion chamber during a first portion of an engine cycle of the piston engine, wherein the first portion of the engine cycle comprises at least a portion of a power stroke and / or an exhaust stroke of the engine cycle. [13] The system of claim 12, wherein the controller is configured to: receives a first feedback from a first sensor indicative of an exhaust gas temperature derived in an exhaust system of the piston engine; and controls the condensate injection system based on the first feedback; wherein the first feedback indicates the exhaust gas temperature at a cylinder head port of the piston engine, an inlet of a turbine of the piston engine, or an aftertreatment system of the piston engine. [14] The system of claim 13, wherein the control of the condensate injection system comprises: reducing an amount of condensate injected into the combustion chamber based on the exhaust gas temperature falling below a low threshold temperature; increasing the amount of condensate based on a temperature that exceeds a high threshold temperature; or any combination of these. [15] The system of claim 13, wherein the controller is configured to receives a second feedback from a second sensor indicating a quantity of condensate in the condensate tank; receives a third feedback from a third sensor indicating one or more operating parameters of the piston engine; and controls the condensate injection system based on the first feedback, the second feedback, or a combination thereof. [16] A method comprising: controlling, via a controller, a condensate injection system configured to be fluidly coupled to a combustion chamber of a piston engine and an exhaust gas recirculation (EGR) system of the piston engine, the condensate injection system comprising a condensate tank configured to store condensate collected from the EGR system, a pump fluidly coupled to the condensate tank, and an injector fluidly coupled to the pump, the controlling comprising: controlling the injector to inject the condensate into the combustion chamber during a first portion of an engine cycle of the reciprocating engine, wherein the first portion of the engine cycle comprises at least a portion of a power stroke and / or an exhaust stroke of the engine cycle. [17] The method of claim 16, wherein controlling the condensate injection system comprises: monitoring an exhaust gas temperature from the piston engine; and monitoring the amount of condensate stored in the condensate tank of the condensate injection system. [18] The method of claim 17, wherein controlling the condensate injection system comprises: evaluating the one or more operating parameters within the piston engine characteristic curves; determining a threshold pressure for injecting the condensate into a cylinder of the reciprocating engine based on the evaluation of the one or more operating parameters; and determining a crank angle for injecting the condensate based on the threshold pressure. [19] The method of claim 18, wherein controlling the condensate injection system comprises: monitoring the piston engine's EGR system for collecting condensate in the condensate tank; controlling the piston engine's EGR system to collect condensate in the condensate tank; or a combination thereof. [20] The method of claim 19, wherein controlling the condensate injection system comprises: receiving feedback from a sensor indicating the amount of condensate in the condensate tank; and controlling the amount of condensate in the condensate tank based on feedback.

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