Tail gas aftertreatment system of diesel engine and pressure fluctuation amplitude determination method

Abstract

The invention discloses a tail gas aftertreatment system (1) of a diesel engine and pressure fluctuation amplitude determination method. The system comprises a treatment agent box (2), a metering jetting module (4), a supply module (3) connected between the treatment agent box (2) and the metering jetting module (4), a tail gas treatment agent tube (6) connected between the metering injection module (4) and the supply module (3), a pressure sensor used for measuring system pressure in the tail gas treatment agent tube (6) and a controller (7), wherein the controller (7) is configured to obtaina system pressure signal sequence from the pressure sensor, if the supply module (3) satisfies a preset working condition within a period corresponding to the system pressure signal sequence, at least based on a frequency domain amplitude value in a preset frequency range obtained by carrying out frequency domain analysis on the system pressure signal sequence, fluctuation amplitude, under excitation by the supply module (3), of the system pressure is determined. The invention further discloses a corresponding method for determining the fluctuation amplitude. The method is simple and reliable.

Description

technical field [0001] The invention relates to an exhaust gas aftertreatment system of a diesel engine and to a method for determining a fluctuation amplitude of the system pressure of the exhaust gas aftertreatment system of a diesel engine, which is excited by a supply module. Background technique [0002] Diesel engines are widely used in machines such as small, heavy or large vehicles, ships, generators and military tanks due to their good reliability, high thermal efficiency and high output torque. However, due to the high content of nitrogen oxides in the exhaust gas emitted by diesel engines, the exhaust gas needs to be treated by a special exhaust gas after-treatment system before it can be discharged into the atmosphere to meet the increasingly stringent environmental protection requirements. [0003] In other words, in order to reduce air pollution, post-treatment of exhaust gas from diesel engines has become a standard configuration of diesel engines. For the tr...

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Problems solved by technology

[0006] However, there is currently no reliable and simple detection method in this regard. Some existing methods require active intervention in the system, for example, the need to fix the operating speed of the supply module, such as making the motor have a fixed excitation frequency

Therefore, during the detection process, the system pressure control is an open-loop method, which will affect the accurate operation of the exhaust after-treatment system

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