Pre-combustion chamber fluid injection

Abstract

A system and method for combustion in an engine includes: a combustion chamber (204); a pre-combustion chamber (202) extending from a first end (222) to a second end (220), the pre-combustion chamber (202) being fluidly connected to the combustion chamber (204) via at least one port (224) located at the first end (222); and a fluid injector (206) configured to introduce fluid into the pre-combustion chamber (202) at the second end (220) after combustion of an air-fuel mixture within the pre-combustion chamber (202).

Description

[0001] This application is a divisional application of the international application filed on November 8, 2019, with international application number PCT / US2019 / 060391, national application number 201980073399.7, entitled "Fluid Injection into Pre-combustion Chamber". Technical Field

[0002] This invention generally relates to internal combustion engines. More specifically, this invention relates to fluid injection in the pre-combustion chamber of a gas engine. Background Technology

[0003] An internal combustion engine may include several combustion cylinders in which an air-fuel mixture is ignited to generate power, which is converted into mechanical power by the driving of a piston. During the combustion of the air-fuel mixture, nitrogen oxides (NOx) gases are generated within the engine, partly due to the high temperatures inside the combustion chamber. It is desirable to limit the amount of nitrogen oxides produced during the operation of an internal combustion engine. Summary of the Invention

[0004] In one example, the combustion system includes a combustion chamber, a pre-combustion chamber, and a fluid injector. The pre-combustion chamber extends from a first end to a second end and is fluidly connected to the combustion chamber via at least one port located at the first end of the pre-combustion chamber. The fluid injector is configured to introduce fluid into the pre-combustion chamber after combustion of the air-fuel mixture within the pre-combustion chamber, and is positioned to introduce fluid into the pre-combustion chamber at the second end of the pre-combustion chamber.

[0005] In another example, a method of operating an engine includes supplying an air-fuel mixture to a pre-combustion chamber of the engine. The pre-combustion chamber extends from a first end to a second end. The method further includes: igniting the air-fuel mixture in the pre-combustion chamber; conveying the ignited air-fuel mixture to a main chamber through at least one port located at the first end of the pre-combustion chamber; and, after combustion of the air-fuel mixture in the pre-combustion chamber, delivering fluid to the pre-combustion chamber through a fluid injector located at the second end of the pre-combustion chamber. The main chamber is in fluid communication with the pre-combustion chamber through at least one port.

[0006] In another example, the engine includes a cylinder, a cylinder head, a pre-combustion chamber, a fluid injector, and a fluid reservoir. The cylinder includes a piston disposed therein, defining a main chamber. The pre-combustion chamber is disposed within the cylinder head, extending from a first end to a second end, and is fluidly connected to the main chamber via at least one port located at the first end. The fluid injector is located at the second end of the pre-combustion chamber and configured to deliver fluid into the pre-combustion chamber, and the fluid reservoir is configured to contain the fluid from the fluid injector. Attached Figure Description

[0007] Figure 1 This is a perspective view of an exemplary system including a gas engine.

[0008] Figure 2 It is a cross-sectional view of an exemplary cylinder and cylinder head of a gas engine including a fluid injector for a pre-combustion chamber.

[0009] Figure 3 This is a flowchart illustrating the method of injecting fluid into the pre-combustion chamber. Detailed Implementation

[0010] This document discloses a pre-combustion chamber for an internal combustion engine, the pre-combustion chamber including a fluid injector positioned and configured to deliver fluid into the pre-combustion chamber after combustion. Combustion in the pre-combustion chamber produces nitrogen oxides (NOx), which can contribute to overall NOx production in the engine. The fluid injector is located at the end of the pre-combustion chamber opposite to the main combustion chamber and is configured to inject a fluid, such as water, into the pre-combustion chamber after combustion of the air-fuel mixture therein. By injecting the fluid, the temperature within the pre-combustion chamber can be reduced, thereby reducing the formation of NOx within the pre-combustion chamber and consequently reducing the total amount of NOx produced by the engine.

[0011] Figure 1 It is a perspective view of an exemplary gas compression system 100 including a gas engine 102, a compressor 104, and a radiator 106.

[0012] System 100 can be used in gas compression applications such as gas lift, gas harvesting, wellhead gas compression, pipeline compression, storage, collection, and re-injection. In one example, system 100 can be a natural gas extraction system in which a gas engine 102 drives a compressor 104 to extract natural gas, and one or more radiators 106 are used for cooling by the compressor 104 and the engine 102. Although illustrated and described with reference to gas compression system 100, the fluid injection systems and methods described herein can be used with any internal combustion engine, including pre-combustion chamber combustion, or in other words, pre-combustion.

[0013] exist Figure 1 In the illustrated embodiment, engine 102 includes a fluid reservoir 108, a fluid pump 110, and a supply line 112. Engine 102 includes a plurality of cylinders 114, each receiving fluid from the supply line 112. Controller 116 is configured to control at least some aspects of the operation of engine 102. Controller 116 can be located anywhere relative to engine 102 and can include any number of digital or analog circuits configured to monitor and control engine 102 via any wired or wireless connection. Controller 116 can be connected to provide control of fluid delivery from fluid reservoir 108 to cylinders 114.

[0014] Controller 116 may include, for example, software, hardware, and a combination of hardware and software configured to perform several functions related to the control of engine 102. Controller 116 may be an analog, digital, or a combination of analog and digital controller, comprising multiple components. As an example, controller 116 may include an integrated circuit board or ICB, a printed circuit board (PCB), a processor, a data storage device, a switch, a relay, or any other component. Examples of processors may include any one or more of a microprocessor, controller, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or equivalent discrete or integrated logic circuitry.

[0015] Controller 116 may include a storage medium for storing and / or retrieving data or other information, such as signals from sensors placed around engine 102. In some examples, the storage device is described as a computer-readable storage medium. For example, a data storage device may be used to store program instructions executed by a processor of controller 116. For example, the storage device may be used by software, applications, or algorithms running on and / or executed by controller 116. The storage device may include short-term and / or long-term memory and may be volatile and / or non-volatile. Examples of non-volatile storage elements include magnetic hard disks, optical disks, floppy disks, flash memory, or various forms of electrically programmable memory (EPROM) or electrically erasable programmable memory (EEPROM). Examples of volatile memory include random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), and other forms of volatile memory known in the art.

[0016] The controller 116 can be configured to communicate with sensors, valves, injectors and other components of the engine 102 via various wired or wireless communication technologies and components using various public and / or proprietary standards and / or protocols.

[0017] The fluid supplied in supply pipe 112 can be delivered to the corresponding pre-combustion chamber for each of cylinders 114 (e.g., Figure 2 (As shown). The pre-combustion chamber can be used by engine 102 to aid combustion and improve fuel efficiency. When the air-fuel mixture burns in the pre-combustion chamber, the temperature rises to a level sufficient to produce nitrogen oxides. Controller 116 can control fluid injection to deliver fluid to the pre-combustion chamber after combustion in the pre-combustion chamber to limit the temperature rise, thereby limiting the production of nitrogen oxides in the engine.

[0018] Figure 2This is a cross-sectional view illustrating the pre-combustion system of the corresponding cylinder 114 of engine 102. The pre-combustion system includes a cylinder head 200, a pre-combustion chamber 202, a main chamber 204, a fluid injector 206, a fuel valve 208, a spark plug 210, a piston 212, a fuel chamber 214, an intake port 216, and an exhaust port 218. The pre-combustion chamber 202 extends from one end 220 to the other end 222 and extends annularly around axis A to define a volume in which an air-fuel mixture can be combusted. The pre-combustion chamber also includes a fluid port 224 configured to fluidly connect the internal volume of the pre-combustion chamber 202 to the main chamber 204, and a pressure sensor 226 configured to sense the pressure within the pre-combustion chamber 202. For example, the pressure sensor 226 may be configured to provide a sensed pressure to the controller 116. Figure 1 ).

[0019] During operation, piston 212 is capable of reciprocating within cylinder 114. Typically, piston 212 reciprocates from bottom dead center (BDC) to top dead center (TDC) in multiple cycles. The volume between top dead center and bottom dead center defines the swept volume, which indicates the volume that the charge can occupy after combustion. The term charge can be understood as either air or a mixture of air and fuel.

[0020] The air intake 216 can be used to introduce air into the cylinder 114. Once the air is burned in the main combustion chamber 204, the combustion products are expelled from the cylinder 114 by the reciprocating motion of the piston 212 with the help of the exhaust port 218.

[0021] In one example, the pre-combustion chamber 202 may be formed as an integrated device with the cylinder head 200. In another example, the pre-combustion chamber 202 may be a separate device that can be connected to the cylinder head 100. In addition to receiving fuel from the fuel chamber 214, the pre-combustion chamber 202 may also be configured to receive intake air from the main combustion chamber 204 through a fluid port 224 during the compression stroke of the piston 212. For example, the fluid port 224 may be formed in the wall at end 222 of the pre-combustion chamber 202.

[0022] The charge from the main chamber 204 can be a mixture, for example, a mixture containing a higher stoichiometric amount of air than the stoichiometric amount of fuel. Therefore, the stoichiometric ratio of the lean air-fuel mixture will be greater than 1. During the compression stroke, the piston 212 moves from bottom dead center to top dead center. Thus, during this movement from bottom dead center to top dead center, the lean air-fuel mixture drawn into cylinder 114 during the previous intake stroke is forced by piston 212 through port 224 into the pre-combustion chamber 202.

[0023] To aid combustion in the main chamber 204, a spark plug 210 can be used to ignite a small amount of fuel in the pre-combustion chamber 202. During the compression stroke, as charge enters the pre-combustion chamber 202 from the main chamber 204, pure fuel (or, in other examples, a premixed air-fuel mixture) can be supplied to the pre-combustion chamber 202 via fuel valve 208. In one example, fuel valve 208 can be configured using a ball valve and a flat valve, which allow fuel to enter the pre-combustion chamber 202 from the fuel chamber 214 due to the increased pressure in the pre-combustion chamber 202. In other examples, fuel valve 208 can be replaced by a fuel injector, for example, one that can be controlled to inject pure fuel or an air-fuel mixture into the pre-combustion chamber 202 at a desired time.

[0024] For example, after fuel from fuel chamber 214 is delivered to pre-combustion chamber 202 and before the end of the compression stroke, spark plug 210 can be controlled to ignite the mixture present in pre-combustion chamber 202. Upon ignition of spark plug 210, the air-rich fuel mixture burns in pre-combustion chamber 202. The burned fuel is then delivered through port 224 to main chamber 204, where it burns the fuel present in main chamber 204.

[0025] After combustion within the pre-combustion chamber 202, fluid can be supplied to the pre-combustion chamber 202 using a fluid injector 206. The fluid can be water, air, nitrogen, or other liquid or gaseous media used to cool the pre-combustion chamber 202 after combustion. By cooling the pre-combustion chamber 202 after combustion, the amount of nitrogen oxides produced during combustion in the pre-combustion chamber can be reduced or eliminated. The mass of fluid supplied to the pre-combustion chamber 202 only needs to be large enough to provide sufficient cooling to prevent the formation of nitrogen oxides. In an illustrative example, the fluid can be water, and the mass of water required to provide sufficient cooling to prevent nitrogen oxide formation is less than 0.1% of the total captured mass of the engine.

[0026] Fluid injector 206 is controlled to deliver fluid to pre-combustion chamber 202 after combustion has occurred. In one example, pressure sensor 226 can be used to detect combustion within pre-combustion chamber 202 in order to control fluid injection. Pressure sensor 226 can be any device capable of outputting an analog or digital signal indicating the pressure within pre-combustion chamber 202. The sensed value can be provided to controller 116, for example, which can monitor the sensed value to monitor the pressure within pre-combustion chamber 202. Controller 116 can detect pressure peaks indicating combustion within pre-combustion chamber 202 and then control fluid injector 206 to deliver a small amount of fluid to pre-combustion chamber 202 to cool it. In other examples, fluid can be delivered to pre-combustion chamber 202 based solely on engine timing. For example, controller 116 can control fluid injector 206 to deliver fluid to pre-combustion chamber 202 for a specific amount of time after the ignition timing of spark plug 210.

[0027] Industrial applicability In an illustrative example, engine 102 is a Caterpillar G3606 A4 engine. Gas engine 102 can use field gas, natural gas, coalbed methane, wellhead gas, propane, or any other suitable gas as fuel. The engine includes several cylinders 114 and several corresponding pre-combustion chambers 202. Figure 3 It is a flowchart illustrating a method 300 for supplying fluid to each pre-combustion chamber of engine 102 after combustion in the pre-combustion chamber.

[0028] In step 302, the compression stroke of piston 212 forces a lean air-fuel mixture into pre-combustion chamber 202. Fuel valve 208 simultaneously delivers fuel to the pre-combustion chamber. In step 304, before the end of the compression stroke of piston 212, the air-fuel mixture in pre-combustion chamber 202 is ignited using spark plug 210. In step 306, method 300 waits until the combustion event in pre-combustion chamber 202 is complete. This can be achieved using closed-loop control, for example, by monitoring the pressure within pre-combustion chamber 202, or using open-loop control, for example, by waiting a specific amount of time after spark plug 210 ignition.

[0029] In step 308, a small amount of water or other fluid is injected into the pre-combustion chamber 202 using a fluid injector 206. This amount is approximately 0.1% of the total captured mass of the engine. This provides cooling to the pre-combustion chamber 202 after the combustion event, thereby limiting the generation of nitrogen oxides within the pre-combustion chamber 202, and consequently limiting the total nitrogen oxide generation of the engine 102.

[0030] The detailed description above is intended to be illustrative, not restrictive. Therefore, the scope of the invention should be determined by reference to the appended claims and the full scope of their equivalents.

Claims

1. An engine, comprising: A cylinder, the cylinder comprising a piston and a main chamber; Cylinder head; A pre-combustion chamber is disposed within the cylinder head and extends from a first end to a second end, wherein the pre-combustion chamber is fluidly connected to the main chamber via at least one port located at the first end; A fluid injector, located at the second end and configured to deliver fluid into the pre-combustion chamber, wherein the fluid is water; A fluid reservoir configured to contain the fluid for use with a fluid ejector; as well as The controller is configured to: The fluid injector is controlled to deliver water into the pre-combustion chamber such that the mass of the water is less than 0.1% of the total captured mass of the engine.

2. The engine according to claim 1, further comprising: A spark plug that extends into the pre-combustion chamber and is configured to ignite the air-fuel mixture within the pre-combustion chamber.

3. The engine according to claim 2, wherein The fluid injector is configured to deliver fluid to the pre-combustion chamber after the air-fuel mixture in the pre-combustion chamber has been burned.

4. The engine according to any one of claims 1-3, further comprising: A fluid pump configured to deliver the fluid from the fluid reservoir to the fluid ejector.

5. The engine according to any one of claims 1-3, wherein The engine is a gas engine configured to drive a gas compressor.

6. The engine according to any one of claims 1-3, further comprising: A pressure sensor is located in the pre-combustion chamber and configured to sense the pressure in the pre-combustion chamber, wherein the controller is configured to monitor the sensed pressure from the pressure sensor via closed-loop control to detect the completion of combustion of the air-fuel mixture in the pre-combustion chamber, and to control the fluid injector to introduce fluid into the pre-combustion chamber when combustion completion is detected in the pre-combustion chamber.

7. The engine according to any one of claims 1-3, further comprising: A fuel valve located at the second end of the pre-combustion chamber and configured to introduce fuel into the pre-combustion chamber before the air-fuel mixture in the pre-combustion chamber is burned.

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