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CN-122014460-A - Diesel injection device and circulation quantitative control method

CN122014460ACN 122014460 ACN122014460 ACN 122014460ACN-122014460-A

Abstract

The invention discloses a diesel gasification device and a circulating quantitative control method. The controller preheats the heating plate and then controls the air inlet valve to open, so that air enters the mixing cavity through the air inlet pipe and the heating net and the pressure in the cavity is regulated to the preset upper limit P tar1 of the pressure threshold, and the controller controls the air inlet valve to open according to the air state and the target equivalence ratio in the mixing cavity The method comprises the steps of calculating target fuel injection quantity of a liquid fuel injector, controlling the liquid fuel injector to finish fuel injection, controlling the opening of an oil gas injection valve by a controller, injecting an oil gas mixture until a preset pressure threshold lower limit P tar2 , calculating residual air quantity and residual fuel quantity in a mixing cavity by the controller based on pressure, temperature and oxygen concentration detection signals after injection, opening an air inlet valve to supplement air to the mixing cavity by the controller until the pressure in the cavity reaches a pressure threshold upper limit P tar1 , closing the air inlet valve, determining air supplement quantity according to pressure difference before and after air supplement, and calculating required oil supplement quantity by combining a target equivalence ratio. The invention realizes the spray crushing and atomizing without depending on the ultrahigh injection pressure.

Inventors

  • QIU TAO
  • ZHANG ZEJIA
  • LEI YAN
  • WU LEI
  • YAN FEIBIN

Assignees

  • 北京工业大学

Dates

Publication Date
20260512
Application Date
20260312

Claims (8)

  1. 1. The diesel gasification device is characterized by comprising a liquid fuel injector (1), a mixing cavity (2), a heating plate (3), a controller (4), an air inlet pipe (5), a heating net (6), an air inlet valve (7), an oil gas injection valve (8), a temperature sensor (9), a pressure sensor (10) and an oxygen concentration sensor (11); the mixing cavity (2) is of a through cavity structure, the upper end face of the mixing cavity is provided with a fuel injection hole, the lower end face of the mixing cavity is in sealing connection with an oil gas injection valve (8), the oil gas injection valve (8) is an electromagnetic control valve, the liquid fuel injector (1) is an electromagnetic control type injector and is arranged at the fuel injection hole of the upper end face of the mixing cavity (2), the injection direction of the liquid fuel injector is perpendicular to the surface of the heating plate (3), the heating plate (3) is arranged in the mixing cavity (2), and the heating plate (3) is connected with the controller (4); The air inlet pipe (5) is communicated with the mixing cavity (2), a heating network (6) is arranged in the air inlet pipe (5), and the heating network (6) is connected with the controller (4), wherein the air inlet valve (7) is an electromagnetic control valve and is arranged on a communication path between the air inlet pipe (5) and the mixing cavity (2) in series; The temperature sensor (9), the pressure sensor (10) and the oxygen concentration sensor (11) are arranged on the side wall of the mixing cavity (2) in a sealing mode, the detection end stretches into the mixing cavity (2), and the signal output end is connected with the controller (4) respectively.
  2. 2. The diesel gasification device as set forth in claim 1, wherein the heating plate (3) has an operating temperature within a preset range of 180-220 ℃, the effective operating surface of the heating plate (3) is rectangular, the effective operating area of the heating plate (3) should completely cover the projection area of the cone-shaped oil beam, and the length L 2 and the width B of the heating plate (3) should satisfy And is also provided with , wherein, For the penetration distance of the oil beam, Is the half cone angle of the oil beam.
  3. 3. The method for quantitatively controlling the circulation of the diesel gasification device according to claim 1 is characterized by being divided into five stages, namely a preheating stage, an air inlet stage, an oil-gas mixing stage, an oil-gas injection stage and an oil-gas supplementing stage.
  4. 4. A method according to claim 3, characterized in that the preheating stage is performed by the controller (4) starting the preheating process of the heating plate (3) and the heating net (6), and the controller (4) controlling the operating state of the heating plate (3) to be within 180-220 ℃ corresponding to the preset operating temperature according to the power supply, current or voltage parameters of the heating plate (3), and simultaneously, the heating net (6) reaching the target temperature.
  5. 5. A method according to claim 3, characterized in that during the intake phase, the controller (4) controls the opening of the inlet valve (7) and, at the same time, controls the intake process based on the detection signal of the pressure sensor (10), when the pressure in the mixing chamber (2) reaches the preset upper pressure threshold limit P tar1 , the controller (4) closes the inlet valve (7) to stop the air introduction, and, at the same time, the controller (4) controls the intake process based on the pressure in the mixing chamber (2) Temperature (temperature) Volume V of mixing chamber (2), gas constant R, air molar mass Equal calculation of air mass before injection ; Formula (1).
  6. 6. A method according to claim 3, characterized in that the controller (4) is arranged to control the mixing chamber during the gas-oil mixing phase in dependence on the air mass in the mixing chamber Theoretical air-fuel ratio of diesel Preset target equivalence ratio Calculating the mass of fuel to be injected for the cycle At the same time, the controller (4) combines the equivalent flow area A, the injection pressure P inj and the diesel density of the liquid fuel injector (1) Pressure in mixing chamber Determining a required injection pulse width t inj , and controlling the liquid fuel injector (1) to complete injection; (2) Formula (3).
  7. 7. A method according to claim 3, characterized in that the controller (4) controls the injection valve (8) to inject the gaseous mixture of fuel and air during the fuel injection phase, when the pressure sensor (10) detects that the pressure in the mixing chamber (2) falls to a preset lower pressure threshold At the same time, the controller (4) stops the injection based on the pressure of the post-injection mixing chamber (2) Temperature (temperature) Oxygen concentration Reference value of oxygen concentration Molar mass of diesel oil Equicalculated mass of remaining air in post-injection mixing chamber (2) And residual fuel mass Taking the residual mass as an initial state parameter of air and oil supplementing control in the next injection cycle; (4) Formula (5).
  8. 8. A method according to claim 3, characterized in that the controller (4) controls the inlet valve (7) to be opened to supply air to the mixing chamber (2) and closes the inlet valve (7) when the pressure in the mixing chamber (2) reaches the preset target pressure P tar1 based on the detection signal of the pressure sensor (10), and after the air supply is completed, the controller controls the air supply to be performed based on the post-air-supply pressure P tar1 , the pre-air-supply pressure P tar2 and the post-air-supply temperature in the mixing chamber (2) The air quality after air supplement is calculated And determining the fuel charge required for the injection cycle in combination with the target equivalence ratio lambda Controlling the liquid fuel injector (1) to inject fuel so as to complete proportioning preparation of the next injection cycle; (6) Formula (7).

Description

Diesel injection device and circulation quantitative control method Technical Field The invention belongs to the technical field of fuel supply of internal combustion engines, and particularly relates to a diesel injection device and a circulating quantitative control method. Background In a fuel supply system of an internal combustion engine, the mixing state of fuel and air directly affects the stability and controllability of the combustion process. Currently, diesel fuel injection technologies mainly include high-pressure common rail injection, direct injection in cylinder (GDI) injection, gas-assist injection, and the like. The high-pressure common rail injection system enables liquid fuel to form high-speed jet flow by establishing high-pressure conditions of 1000-2000 bar and realizes atomization by means of jet flow crushing effect, the GDI injection system is adaptive to light liquid fuel and divides liquid drops by mechanical shearing effect of the high-pressure jet flow, and the air-assisted injection system introduces high-pressure air to impact with the fuel jet flow so as to enhance the liquid drop crushing effect. The fuel injection technology uses mechanical breaking of liquid fuel as a main atomization mechanism, the fuel exists in the form of liquid drops all the time in the injection and mixing processes, and is limited by physical characteristics such as surface tension and viscosity of the liquid fuel, and certain technical limitations still exist, namely, on one hand, the liquid drops are reagglomerated in the injection and mixing processes to cause higher local fuel concentration, on the other hand, the mixing process of the fuel and the air mainly depends on jet flow diffusion and liquid drop evaporation, the mixing uniformity is greatly influenced by working conditions and structures, and the stability and consistency are difficult to keep under different running conditions. In addition, to achieve a better atomization, the system generally needs to continuously maintain a higher injection pressure, increasing the structural complexity and control difficulty of the injection system. Disclosure of Invention The invention aims to solve the problem that the existing diesel injection supply technology generally relies on high injection pressure to realize mechanical crushing and atomization of liquid fuel, and because the fuel still exists in the form of liquid drops in the injection and mixing process, the atomization and mixing effect is sensitive to the injection pressure and the change of working conditions, and is difficult to keep stable and consistent under different conditions, and meanwhile, the high-pressure injection system has a complex structure and high control requirement. The invention provides a diesel gasification device and a circulating quantitative control method. The liquid diesel is sprayed in a jet flow mode through the heating plate arranged in the mixing cavity and contacts with the working surface of the heating plate to realize gasification, and the controller controls the working temperature of the heating plate in a preset interval of 180-220 ℃ by combining the distillation range characteristic (180-360 ℃) of the diesel and the safety threshold value (220-250 ℃) of the spontaneous combustion temperature of the diesel so as to meet the gasification requirement of the diesel. The controller carries out cooperative control on the air inlet process and the fuel injection process based on temperature, pressure and oxygen concentration detection signals, so that the pressure and the equivalence ratio in the mixing cavity are stabilized in a target range, and the gaseous oil-gas mixture is injected and output through an oil-gas injection valve. The diesel gasification injection device comprises a liquid fuel injector, a mixing cavity, a heating plate, a controller, an air inlet pipe, a heating net, an air inlet valve, an oil gas injection valve, a temperature sensor, a pressure sensor and an oxygen concentration sensor. The liquid fuel injector is an electromagnetic control injector, is arranged at the fuel injection hole at the upper end of the mixing cavity, the injection direction of the liquid fuel injector is perpendicular to the surface of a heating plate, the heating plate is a high-temperature-resistant metal heat conduction member and is arranged in the mixing cavity, the heating plate is connected with a controller, and the working temperature of the heating plate is adjusted to be maintained at 180-220 ℃ by the controller. The projection area radius of the conical oil beam formed by the liquid fuel injector on the working surface of the heating plate isThe effective working surface of the heating plate is rectangular, the length is L 2, the width is B, and the requirements are satisfiedAnd is also provided withThe effective working area of the heating plate is enabled to completely cover the oil beam projection area. One end of the air inlet pipe is an