DPF regeneration device for mixing two-phase flow mediums and exhaust air temperature increment strategy of DPF regeneration device

Abstract

The invention provides a DPF regeneration device for mixing two-phase flow mediums and an exhaust air temperature increment strategy of the DPF regeneration device. The inlet of an exhaust pipe is provided with a nozzle; a diesel oxidation catalyst (DOC) and a particulate filter (DPF) are arranged inside the exhaust pipe; the DPF regeneration device comprises a two-phase flow medium mixing deviceand a control system; the two-phase flow medium mixing device is used for providing the two-phase flow mediums which are mixed in the nozzle; the control system comprises a control unit, a DPF temperature sensor, a DOC front exhaust air temperature sensor and a DPF pressure difference sensor; the DPF temperature sensor is used for measuring the temperature of the inlet and the outlet of the DPF; the DOC front exhaust air temperature sensor is used for measuring the temperature of the inlet of the DOC; and the pressure difference sensor of the DPF is used for measuring the pressure difference of the inlet and the outlet of the DPF. According to the DPF regeneration device provided by the invention, the two-phase flow mediums are sprayed into the exhaust pipe via the nozzle; oil gas is ignited by virtue of an ignition plug; and the control system implements state monitoring and state control of the overall regeneration process.

Description

Technical field [0001] The present invention relates to the technical field of DPF exhaust gas aftertreatment, and in particular to a DPF regeneration device with mixed two-phase flow media and its exhaust temperature rising strategy. Background technique [0002] Diesel engines are widely used in transportation, industrial and agricultural production and other fields with their advantages of good fuel economy, high reliability, high thermal efficiency and long service life. The main pollutants emitted by diesel engines are nitrogen oxides NOX and particulate matter (PM), which cause environmental pollution and seriously endanger human health. In recent years, increasingly stringent emission regulations have placed higher technical requirements on diesel engine PM emissions. Diesel Particulate Filter (DPF, DieselParticulate Filter) technology is considered to be the most effective post-treatment method for reducing PM at present, with a collection efficiency of more than 90%. DP...

AI Technical Summary

Problems solved by technology

The oxygen content in the exhaust gas is affected by the operating conditions of the engine. When the engine is working at a high load, the oxygen concentration in the exhaust gas is low, which will affect the combustion of the injected fuel and the combustion of PM collected on the DPF filter body, so that the DPF can be regenerated decreased efficiency;

[0006] 2. After the fuel is pressurized by the gear pump, it is directly sprayed into the exhaust through the nozzle, and its atomization performance is poor

The fuel injection pressure is only about 0.8MPa, and the porous small-aperture nozzle is adopted, and the particle size of the fuel spray is still enlarged, generally above 80 μm, which affects its ignition characteristics and combustion speed, which in turn will affect the regeneration of DPF;

[0007] 3. System reliability is not high

When the oxygen concentration in the exhaust gas is low or the exhaust gas temperature is very low, it is often difficult to ignite, and it is easy to cause the injected fuel to fail to ignite.

After the injection is stopped, there will be fuel residue in the nozzle, which may easily cause carbon deposits or even blockage of the nozzle;

[0008] 4. Unable to achieve accurate metering of injected fuel

However, the pressure reduction caused by the wear of the gear pump will change the amount of fuel injected

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