Direct injection diesel engine premixed combustion method and its device

Abstract

The present invention utilizes the reasonal collision of oil beam jetted by high-pressure oil sprayer with surface of combustion chamber to form fuel oil and air several mixed modes and obviously raise oil-air mixed rate so as to implement premixed combustion of directly-jetted diesel engine. The equipment for implementing said invented method is characterized by that the interior of combustion chamber is equipped with a ring-shaped column body, and the outer side of said ring-shaped column body is external annular combustion chamber, and its inside is central combustion chamber. The oil-jet nozzle has several oil jet holes, and the centre line of oil jet nozzle and the centre line of combustion chamber are coincided, and the included angle of elongation line of axis of oil jet hole and centre line of oil jet nozzle is 60-75 deg.

Description

technical field [0001] The invention belongs to the field of internal combustion engines, and specifically relates to a premixed combustion method and device for a direct-injection diesel engine. Background technique [0002] As countries around the world have increasingly stringent requirements on vehicle emissions, direct-injection diesel engines, which are the main power of vehicles, are facing the challenge of low emissions. The traditional direct-injection diesel combustion system injects diesel oil into the combustion chamber through a high-pressure injector, and the spray beam formed interacts with the air in the combustion chamber to achieve spray mixed combustion. This combustion method is mainly in the form of diffusion combustion, and the concentration distribution of the oil beam Very inhomogeneous and high combustion temperatures lead to high levels of soot and harmful emissions of nitrogen oxides. Recently, internal combustion engine researchers have proposed ...

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Problems solved by technology

The above fuel collision and mixing devices all use a single oil beam to collide with the collision surface of the boss directly below, or collide with the walls around the combustion chamber, so it is difficult to effectively use the air movement of the entire combustion chamber, and the mixing effect is not good.

[0004] U.S. Patent No. US5467757, "Compression-ignition type engine and combustion method of same", adopts the method of injecting diesel oil into the combustion chamber in advance and mixing it with air at 60°CA before the top dead center of the compression stroke of the diesel engine. Premixed gas, recompression combustion, can significantly improve soot and NO under certain conditions x Emissions, but it is difficult to control the ignition time and combustion rate of the mixture. When the diesel engine is under high load, it is easy to generate knocking and deteriorate the combustion; SAE paper No.892068, titled "Homogeneous-Charge Compression Ignition (HCCI) Engines)", proposed to use the exhaust gas recirculation method to control the premixed combustion process of diesel engines, including the ignition point, combustion rate, etc., but did not give a specific control method; US Patent No. US2002026926, "Premixed with combustion optimization control Compression ignition engine (Premixed chargecompression ignition engine with optimal combustion control)" provides an electronic control system to control the combustion process of diesel-air premixed gas in diesel engines, including combustion ignition time, combustion rate, pressure and temperature in the combustion chamber, etc. But the control system is complex and expensive

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