CN-117145658-B - Ammonia gas internal combustion engine system and control method thereof

CN117145658BCN 117145658 BCN117145658 BCN 117145658BCN-117145658-B

Abstract

The application relates to an ammonia gas internal combustion engine system and a control method thereof, belonging to the field of internal combustion engines. The ammonia gas internal combustion engine system comprises an ammonia supply device, an ammonia decomposition device, an engine body device and an ignition device, wherein the ammonia supply device comprises an ammonia ejector for providing ammonia, the ammonia decomposition device comprises a catalyst for decomposing the ammonia into nitrogen and hydrogen, the engine body device comprises a main combustion chamber, the ignition device is partially positioned in the main combustion chamber, the control method of the ammonia gas internal combustion engine comprises the steps of controlling the total flow of the ammonia to be 20-23L/min, simultaneously controlling the decomposition rate of the ammonia in the ammonia decomposition device to be 50-60%, and controlling the equivalent ratio to be 1.05-1.23. The control process takes the dynamic characteristic as the basis, gives consideration to the better burnout rate characteristic and emission characteristic, provides reference basis for the design and application of the ammonia internal combustion engine, and is a practical ammonia internal combustion engine control method.

Inventors

LIU YANG
ZHANG JUAN

Assignees

中国科学院青岛生物能源与过程研究所

Dates

Publication Date: 20260505
Application Date: 20230830

Claims (4)

1. A control method of an ammonia gas internal combustion engine system, characterized in that the ammonia gas internal combustion engine system comprises a fuel supply module and an internal combustion engine module, the internal combustion engine module comprises an internal combustion engine body, the internal combustion engine body is a double spark plug ignition type internal combustion engine, the fuel supply module is communicated with an intake valve of the internal combustion engine body, and the fuel supply module is used for providing required fuel gas for the internal combustion engine module; The fuel supply module comprises an ammonia gas cylinder, a first flowmeter and an ammonia decomposer, wherein the ammonia gas cylinder is communicated with the first flowmeter, the other end of the first flowmeter is communicated with the ammonia decomposer, a gas pressure reducing valve is arranged between the first flowmeter and the ammonia decomposer, and the opposite end of the first flowmeter of the ammonia decomposer is communicated with an intake valve of an internal combustion engine body; The control method comprises the following steps: 1) Ammonia supply and decomposition, namely controlling ammonia in an ammonia gas cylinder to enter an ammonia decomposer and catalytically decomposing the ammonia into ammonia and hydrogen; 2) The air suction is that an air inlet valve of the internal combustion engine body is opened, an air outlet valve of the internal combustion engine body is closed, and the air in the ammonia decomposer enters the internal combustion engine body; 3) Ignition, namely, the ignition device performs ignition; 4) Controlling the opening of an air outlet valve of the internal combustion engine body and the closing of an air inlet valve of the internal combustion engine body; and controlling the total flow of the ammonia gas provided by the ammonia gas cylinder to be 20-22.5L/min, controlling the decomposition rate of the ammonia gas in an ammonia decomposer to be 50-55%, and controlling the equivalent ratio to be 1.10-1.12.
2. The method for controlling an ammonia gas internal combustion engine system according to claim 1, wherein the total flow rate of ammonia gas supplied from the ammonia gas cylinder is controlled to be 22.5L/min, the decomposition rate of ammonia gas in the ammonia decomposer is controlled to be 50%, and the equivalence ratio is controlled to be 1.12.
3. A control method of an ammonia internal combustion engine system according to claim 1, characterized in that the ammonia internal combustion engine system further comprises a turbocharger.
4. A control method of an ammonia gas internal combustion engine system according to claim 1, characterized in that the ammonia gas internal combustion engine system further comprises an exhaust gas circulator for recovering the discharged exhaust gas and supplying heat to the ammonia decomposer.

Description

Ammonia gas internal combustion engine system and control method thereof Technical Field The application relates to an ammonia gas internal combustion engine system and a control method thereof, belonging to the field of internal combustion engines. Background Ammonia is an excellent hydrogen energy carrier. The ammonia molecule consists of a nitrogen atom and three hydrogen atoms, the hydrogen atoms account for 17.6% of the mass of the ammonia molecule, the ammonia molecule structure can show that the ammonia does not contain carbon atoms, the ammonia can not generate carbon dioxide in the combustion process, the completely combusted product is clean water and nitrogen, the emission problem of carbon dioxide does not exist, and the greenhouse effect is not aggravated. The main challenges of ammonia as fuel for internal combustion engines are poor ignition and combustion performance of ammonia, which is mainly characterized by high ignition energy of ammonia, slow flame propagation speed and narrow flammability limit of ammonia, so that the direct application of ammonia fuel to internal combustion engines has poor and satisfactory combustion effect. In order to improve the ignition and combustion of ammonia in an internal combustion engine, researchers have proposed the following solutions that firstly, a dual-fuel system mixes ammonia with gasoline or other hydrocarbon fuels for combustion, and secondly, a fuel auxiliary agent uses hydrogen as the fuel auxiliary agent. For the first, in spark-ignition internal combustion engines, the hydrocarbon fuel used mainly in ammonia and hydrocarbon dual fuel systems is typically petroleum, methane or other carbonaceous fuels, which certainly also produce carbon dioxide, carbon monoxide and soot products, again subject to regulations relating to carbon emissions. For the second, the use of carbon-free fuel aid hydrogen to enhance the ignition and combustion performance of ammonia in spark-ignition internal combustion engines is one of the most effective ways to decompose part of the ammonia into hydrogen and nitrogen by using catalytic decomposition devices, the resulting ammonia partial decomposition gas having good ignition and combustion characteristics. However, adding hydrogen as an auxiliary agent requires adding a new gas storage device and a ventilation pipeline, firstly increases the volume of equipment, secondly has potential safety hazard in storing hydrogen, and also requires regulating and controlling the gas supply ratio of hydrogen and ammonia, so that the control difficulty is high, and the research on the aspect in the prior art is less. Based on the problem of pain points of ammonia applied to an internal combustion engine, researchers propose a new idea that an ammonia decomposing device is installed before the ammonia enters an internal combustion engine cylinder to decompose the ammonia partially, ammonia partial decomposed gas of ammonia, hydrogen and nitrogen is formed and then enters the cylinder to burn, the ignition energy of the hydrogen is low, the flame propagation speed is high, the property of the limit width of the combustible is complementary with that of the ammonia, and the ignition and combustion performance of the ammonia are improved by utilizing the hydrogen, so that the good combustion performance of ammonia fuel in the internal combustion engine is realized, and finally the carbonization-free operation of the internal combustion engine is realized. In the prior art, samyer et al decomposed ammonia into hydrogen and nitrogen by a decomposer composed of stainless steel, the inside of which was loosely filled with a catalyst, and the entire decomposer was electrically heated by a heater, and as a result, it was found that about 25% of ammonia was decomposed. Ryu and the like provide heat for the ammonia decomposer by utilizing tail gas waste heat, and ammonia is decomposed by a catalyst to form partial decomposed gas of ammonia, hydrogen and nitrogen, and the partial decomposed gas is uniformly mixed with air and gasoline and then enters an internal combustion engine for combustion. Compared with an ammonia gas internal combustion engine without decomposition, the power of the ammonia gas internal combustion engine after decomposition is averagely improved by 0.2 kW, the emission of nitrogen oxides is reduced by 25 g/kW.h, the emission of ammonia gas is reduced by 2.5 g/kW.h, and the emission of carbon monoxide is reduced by 8 g/kW.h. Frigo, et al developed and studied a decomposer suitable for an ammonia internal combustion engine, wherein the catalyst in the decomposer is a ruthenium-based catalyst, and experiments show that at the rotating speed of the internal combustion engine of 3000 rpm, the thermal efficiency of the partial decomposed gas of ammonia is similar to that of a gasoline internal combustion engine and is about 28%. Ezzat et al have determined the thermodynamic advantage of partial decomposition of ammonia in an