Constant-volume combustion bomb system and method with simulation of various combustion modes of methanol/diesel dual-fuel engine

Abstract

The invention relates to a constant-volume combustion bomb system and method with simulation of various combustion modes of a methanol / diesel dual-fuel engine. The system is composed of a constant-volume combustion bomb, a diesel injector, a diesel injection system connected to the diesel injector, a methanol injector, a methanol injector system connected to the methanol injector, an air intake system, an exhaust system, a pressure sensor, a synchronous data acquisition card, a high-speed camera, and an upper computer. According to the invention, with adjustment on the injection time of methanol relative to the diesel, several kinds of different combustion modes such as methanol ignition by diesel, simultaneous ignition of diesel and methanol, and autoignition of methanol earlier than diesel are realized; uniform premixing and concentration layering of methanol in the constant-volume combustion bomb are realized respectively; and the injection pressure of methanol is adjusted flexibly.

Description

Technical field: [0001] The invention relates to the technical field of constant-volume incendiary bombs for internal combustion engines, and further relates to a constant-volume incendiary bomb system and method for simulating multiple combustion modes of a methanol / diesel dual-fuel engine. Background technique: [0002] In order to meet the increasingly stringent automobile emission regulations and fuel consumption regulations, more and more advanced engine technologies have been applied, including in-cylinder direct injection, high-pressure injection, multiple injection, variable fuel injection timing, variable valve lift (VVL ) and timing (VVT), supercharging and intercooling, exhaust gas recirculation (EGR) and other in-cylinder purification technologies to improve combustion, and three-way catalytic converter (TWC), oxidation converter (DOC), selective catalytic reduction (SCR) However, whether it is in-cylinder purification technology or after-treatment technology, th...

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Problems solved by technology

There are three main technical solutions for the application of alternative fuels on engines: the first is the blending method, that is, the two fuels are mixed to form a homogeneous and stable liquid fuel through a co-solvent. This method is simple and easy, but the disadvantages are The two fuels are prone to stratification as the temperature changes, and this method cannot achieve a high substitution rate due to low mutual solubility; the second method is a complete replacement, that is, the engine only uses alternative fuels, such as methanol engines, natural gas engines and liquefied petroleum Gas engines, etc., this method can achieve 100% replacement rate, but due to the different physical and chemical properties of the fuel, it is necessary to make major changes to the engine, and the basic supporting facilities such as fuel filling have not yet been popularized; the third method is the ignition method , that is, the two fuels adopt two sets of independent supply systems. The patent document CN1470752A discloses a diesel / methanol combined combustion technology (Diesel Methanol Compound Combustion, DMCC), which proposes to inject methanol into the intake port of the diesel engine to form a homogeneous mixture with air Enter the cylinder, and then directly inject diesel into the cylinder to ignite the mixture of methanol and air. This method is flexible and convenient in practical applications, without major changes to the original machine, and can achieve a high replacement rate

[0004] The published patent documents CN103245511A, patent documents CN104391074A, patent documents CN105372072A, patent documents CN106353098A, and patent documents CN106404410A are only applicable to the spraying and combustion research of a single fuel; Methanol is injected into the air intake pipeline at a certain temperature, and the vacuum is pre-evacuated to form a negative pressure in the inner cavity of the constant volume incendiary bomb, thereby sucking methanol into the constant volume incendiary bomb. However, this method has some obvious shortcomings: (1) The methanol cannot be controlled It is difficult to target different temperature conditions, especially under high temperature conditions, when diesel oil is injected into the methanol hot atmosphere and the dual fuels ignite and burn; Methanol will spontaneously ignite, which greatly limits the scope of research on this dual-fuel combustion, especially during the operation of an actual diesel-methanol dual-fuel engine. (3) The stratified combustion of methanol cannot be realized, because methanol is pre-mixed into the constant-volume incendiary bomb, and the constant-volume incendiary bomb is already a homogeneous mixture of methanol and air before diesel injection, and methanol cannot be realized Concentration Stratification

[0005] To sum up, solve the technical problems such as uncontrollable methanol addition time, narrow ambient temperature and pressure range, and inability to achieve methanol concentration stratification in the study of dual-fuel combustion in constant volume incendiary bombs.

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