A device for measuring the influence of air-fuel ratio on combustion performance of ammonia engine

Abstract

This utility model relates to the field of ammonia engine fuel technology, specifically to a device for measuring the effect of air-fuel ratio on the combustion performance of an ammonia engine. The device includes an intake manifold with several intake pipes and a fuel rail between them. A fuel nozzle is located at the lower end of the fuel rail and is connected to the intake pipes. A fuel supply pipe is located at the upper end of the fuel rail and is connected to a fuel tank. The intake manifold is connected to the intake pipes via a bend, and several ammonia nozzles are located on the bend, connected to the ammonia fuel tank. The intake manifold is also connected to the engine. This invention solves the current problem of high fuel cost, low efficiency, and environmental unfriendliness in ammonia engines, necessitating a device for measurement.

Description

Technical Field

[0001] This utility model relates to the field of ammonia engine fuel technology, specifically to a device for measuring the effect of air-fuel ratio on the combustion performance of ammonia engines. Background Technology

[0002] Ammonia engines, as an emerging zero-carbon power technology, have received widespread attention in recent years. Because ammonia does not contain carbon atoms, it achieves carbon neutrality at the source. Therefore, ammonia is an excellent alternative fuel for internal combustion engines to achieve the dual-carbon goal. However, the combustion of ammonia has some difficulties: 1. Difficulty in ignition, 2. Unstable flame, 3. Slow flame propagation speed. Therefore, the combustion of pure ammonia has problems such as misfire. The current solution is to mix it with other fuels for co-combustion. That is, the dual-fuel combustion mode is the strategy commonly used to accelerate the combustion of ammonia.

[0003] Ammonia fuel engines have the advantage of outstanding environmental performance. The main byproducts of ammonia combustion are nitrogen and water, with no carbon dioxide or sulfur oxide emissions, meeting the zero-carbon target. Compared to hydrogen fuel, ammonia has lower storage and transportation costs (the storage cost of liquid ammonia is only 0.2% of that of liquid hydrogen), and ammonia synthesis technology is mature. China is the world's largest producer, with abundant resources.

[0004] Energy density and storage / transport advantages: Ammonia's volumetric energy density (3.5 kWh / L) is 50% higher than liquid hydrogen, and it can be liquefied at -33℃ or 9 atmospheres. Its storage and transportation requirements are far lower than hydrogen's -253℃, allowing for the use of existing pipelines, railways, and other infrastructure. Engine performance potential: Ammonia has a high octane rating and strong anti-knock properties, allowing for higher compression ratios and a thermal efficiency of 50%-60%, twice that of traditional internal combustion engines. GAC's 2.0L ammonia engine has achieved 120kW power while reducing carbon emissions by 90%.

[0005] Using gasoline + ammonia dual fuel can significantly improve both economy and emissions while maintaining the original engine's power performance. It also results in less air pollution. However, a device is needed to investigate the effects of gasoline blending with ammonia on combustion and nitrogen-based pollutant emissions under different excess air coefficients αa, and to analyze and discuss the formation patterns of NOx and N2O emissions. The aim is to provide a reference for the control of combustion and nitrogen-based pollutant emissions in ammonia-blended engines.

[0006] In summary, a device for measuring the effect of air-fuel ratio on the combustion performance of ammonia engines is proposed to solve the problems mentioned in the background art. Utility Model Content

[0007] The purpose of this invention is to provide a device for measuring the effect of air-fuel ratio on the combustion performance of ammonia engines, thereby addressing the current problems of high fuel costs, low efficiency, and environmental unfriendliness in ammonia engines, which necessitate a device for measurement.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0009] A device for measuring the effect of air-fuel ratio on the combustion performance of an ammonia engine includes an intake manifold with a plurality of intake pipes. A fuel rail is provided between the intake pipes. A fuel nozzle is provided at the lower end of the fuel rail and is connected to the intake pipes. A fuel supply pipe is provided at the upper end of the fuel rail and is connected to a fuel tank. The intake manifold is connected to the intake pipes via a bend. A plurality of ammonia nozzles are provided on the bend and are connected to an ammonia fuel tank. The intake manifold is connected to an engine. A connector is provided on the fuel nozzles. The connector, the ammonia nozzles, and the fuel supply pipe are connected to an ECU via a wiring harness.

[0010] Furthermore, there are four ammonia nozzles, which are evenly distributed in a circular pattern on the bend, and the joint between the bend and the intake manifold is a square joint.

[0011] Further specified, an ammonia flow meter, an ammonia pump, and a pressure regulating valve are respectively installed on the pipeline between the ammonia nozzle and the ammonia fuel tank. The pressure regulating valve is used to regulate the pressure of the pipeline, the ammonia flow meter is used to detect the flow rate of ammonia in the pipeline, and the ammonia pump is used for ammonia transmission between the ammonia fuel tank and the ammonia nozzle.

[0012] Furthermore, a rail pressure sensor is also provided at the upper end of the gasoline rail. The rail pressure sensor is used to detect the pressure of the gasoline rail, and the rail pressure sensor is connected to the ECU via a wiring harness.

[0013] The advantages of this utility model over the current technology are as follows:

[0014] The gasoline in the fuel tank is atomized and enters the cylinder through the intake manifold via the fuel supply pipe. The ammonia nozzle injects ammonia at a pressure of 0.45 MPa. The ammonia and fresh air are mixed evenly in the intake manifold and mixing chamber, and then enter the cylinder through the intake manifold. During the test, the surface of the liquid ammonia tank was controlled at 50°C to ensure the stability of the ammonia injection pressure. Attached Figure Description

[0015] Figure 1 This is a three-dimensional schematic diagram of the present invention.

[0016] Figure 2 This is a schematic diagram of the system connection of this utility model.

[0017] The markings in the diagram correspond to: 1-Intake manifold, 2-Intake pipe, 3-Fuel rail, 4-Fuel injector, 5-Fuel supply pipe, 6-Bend, 7-Intake pipe, 8-Ammonia injector, 9-Rail pressure sensor, 10-Ammonia fuel tank, 11-Ammonia flow meter, 12-Ammonia pump, 13-Pressure regulating valve, 14-Fuel tank, 15-Fuel filter, 16-Engine, 17-Connector, 18-ECU. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solution of this utility model, the technical solution of this utility model will be further described below in conjunction with the accompanying drawings and embodiments.

[0019] Example:

[0020] like Figures 1-2 As shown, a device for measuring the effect of air-fuel ratio on the combustion performance of an ammonia engine includes an intake manifold 1, a plurality of intake pipes 2 disposed on the intake manifold 1, a fuel rail 3 disposed between the plurality of intake pipes, a fuel injector 4 disposed at the lower end of the fuel rail 3, and a fuel supply pipe 5 and a rail pressure sensor 9 disposed at the upper end of the fuel rail 3. The rail pressure sensor 9 is used to detect the pressure of the fuel rail 3. The fuel injector 4 is connected to the intake pipes 2, the fuel supply pipe 5 is connected to the fuel tank 14, and a fuel supply pipe is disposed on the pipeline between the fuel tank 14 and the fuel supply pipe 5. The filter 15 and intake manifold 1 are connected to the intake manifold 7 via a bend 6. Several ammonia nozzles 8 are provided on the bend 6. The ammonia nozzles 8 are evenly distributed on the bend 6 in a circumferential manner. The joint between the bend 6 and the intake manifold 1 is a square joint. The intake manifold 1 is connected to the engine 16. The gasoline nozzle 4 is provided with a connector 17. The connector 17, rail pressure sensor 9, ammonia nozzles 8 and gasoline supply pipe 5 are all connected to the ECU 18 via a wiring harness. The ECU 18 is used to control the ratio of ammonia to gasoline.

[0021] It also includes an ammonia fuel tank 10, which is connected to an ammonia nozzle 8. An ammonia flow meter 11, an ammonia pump 12, and a pressure regulating valve 13 are respectively installed on the pipeline between the ammonia fuel tank 10 and the ammonia nozzle 8. The pressure regulating valve 13 is used to regulate the pressure of the pipeline, the ammonia flow meter 11 is used to detect the flow rate of ammonia in the pipeline, and the ammonia pump 12 is used for the transmission of ammonia between the ammonia fuel tank 10 and the ammonia nozzle 8.

[0022] The experiment was conducted on a 12.9L, six-cylinder spark-ignition engine with natural aspiration. Gasoline was atomized from the intake manifold 1 and entered the cylinder via intake port injection. Ammonia was injected by the ammonia nozzle 8 at a pressure of 0.45MPa. The ammonia and fresh air were mixed evenly in the intake manifold and mixing chamber and then entered the cylinder through the intake manifold 1. During the experiment, the surface of the liquid ammonia tank was controlled at 50°C to ensure the stability of the ammonia injection pressure.

[0023] The test bench is equipped with an electric dynamometer for speed control. In-cylinder pressure is measured by a spark plug-type in-cylinder pressure sensor and collected and analyzed by a combustion analyzer. In-cylinder pressure is recorded for 200 consecutive cycles. The ECU can adjust the fuel injection quantity and ammonia injection quantity, thereby controlling the ammonia blending ratio and overall φa. Emissions are collected and analyzed by an emission meter that measures NOx (NO and NO2 only), N2O, NH3, CO, and total hydrocarbons (THC). For each test operating point, emission data is continuously collected for approximately 50 seconds. The emission sampling tube is heated and temperature-controlled during the test to prevent water vapor condensation and ammonia absorption. Emissions measured in the test are volume fractions. Liquid fuel flow rate is measured by a volumetric fuel consumption meter, and ammonia flow rate is measured by a thermal mass flow meter. Ignition timing (ST) sweeping was performed under constant φa and ammonia blending ratio, with the combustion center of gravity (CA50) located between 0 and 5°CA. When significant knocking occurs within the ATDC range or in the cylinder, this operating condition is considered the maximum ignition advance angle condition. The ammonia blending ratio X is calculated as the proportion of ammonia energy input into the cylinder to the total fuel energy, using the formula X = (m1lVH1) / (m1lVH1 + m2lVH2), where m1 is the mass flow rate of ammonia, lVH1 is the lower heating value of ammonia, m2 is the mass flow rate of gasoline or ethanol, and lVH2 is the lower heating value of gasoline or ethanol. For one working cycle, CA10, CA50, and CA90 are the crankshaft angles corresponding to 10%, 50%, and 90% of the total accumulated heat release, respectively.

[0024] Blending gasoline with ammonia can effectively suppress engine knocking under mild lean-burn conditions (φa = 1.2) and medium-to-high load conditions, and expand the ignition timing range, optimizing CA50 within the 5°–10° CA ATDC range, thereby helping to improve engine fuel economy. When φa is 1.0 and 1.2, blending with 30% ammonia can increase the engine's indicated thermal efficiency by approximately 3.5% and 1.9%, respectively. Without ammonia blending, NOx emissions are controlled by the thermal NOx mechanism. After introducing 35% ammonia, NOx emissions increase significantly and are controlled by both thermal and fuel-based NOx formation pathways. After blending with ammonia, when φa = 1.0, NOx emissions decrease with ignition advance, while when φa is 1.2 and 1.4, NOx emissions increase with ignition advance.

[0025] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0026] The above provides a detailed description of the device for measuring the effect of air-fuel ratio on the combustion performance of an ammonia engine. The specific embodiments are only used to help understand the method and core idea of ​​this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from it, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A device for measuring the effect of air-fuel ratio on the combustion performance of an ammonia engine, comprising an intake manifold (1), characterized in that: The intake manifold (1) is provided with several intake pipes (2), and a gasoline rail (3) is provided between the several intake pipes (2). A gasoline nozzle (4) is provided at the lower end of the gasoline rail (3). The gasoline nozzle (4) is connected to the intake pipe (2). A gasoline supply pipe (5) is provided at the upper end of the gasoline rail (3). The gasoline supply pipe (5) is connected to the gasoline tank (14). The intake manifold (1) is connected to the intake pipe (7) through a bend (6). Several ammonia nozzles (8) are provided on the bend (6). The ammonia nozzles (8) are connected to the ammonia fuel tank (10). The intake manifold (1) is connected to the engine (16). A connector (17) is provided on the gasoline nozzle (4). The connector (17), the ammonia nozzle (8), and the gasoline supply pipe (5) are all connected to the ECU (18) through a wiring harness.

2. The device for measuring the influence of air-fuel ratio on the combustion performance of an ammonia engine according to claim 1, characterized in that: There are four ammonia nozzles (8), which are evenly distributed on the bend (6) in a circular manner. The joint between the bend (6) and the intake manifold (1) is a square joint.

3. The device for measuring the influence of air-fuel ratio on the combustion performance of an ammonia engine according to claim 1, characterized in that: An ammonia flow meter (11), an ammonia pump (12), and a pressure regulating valve (13) are respectively installed on the pipeline between the ammonia nozzle (8) and the ammonia fuel tank (10). The pressure regulating valve (13) is used to regulate the pressure of the pipeline, the ammonia flow meter (11) is used to detect the flow rate of ammonia in the pipeline, and the ammonia pump (12) is used for ammonia transmission between the ammonia fuel tank (10) and the ammonia nozzle (8).

4. The device for measuring the influence of air-fuel ratio on the combustion performance of an ammonia engine according to claim 1, characterized in that: A rail pressure sensor (9) is also provided at the upper end of the gasoline rail (3). The rail pressure sensor (9) is used to detect the pressure of the gasoline rail (3). The rail pressure sensor (9) is connected to the ECU (18) through a wiring harness.

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