Diesel particulate filter (DPF) carbon accumulation estimation method

Abstract

The invention discloses a diesel particulate filter (DPF) carbon accumulation estimation method. The difference between total pressure before a DPF and total pressure after the DPF is detected by a pressure difference sensor, the total flow resistance of the DPF is obtained according to the difference between the total pressure before the DPF and the total pressure after the DPF and exhaust gas volume flow, the flow resistance generated by the residual carbon of the DPF is obtained according to ash content mass and the exhaust gas volume flow, white carrier flow resistance and the flow resistance generated by the residual carbon subtracted from the total flow resistance gives flow resistance generated by accumulated carbon, and according to the flow resistance generated by the accumulated carbon and the exhaust gas volume flow, carbon accumulation can be obtained; the ash content mass is obtained by integrating exhaust gas mass flow and the rotational speed of an engine. The carbon accumulation increment estimation method put forward by the invention can work out the increment of carbon accumulation on the basis of current total flow resistance, current ash content mass and current exhaust gas volume flow, and then obtains current carbon accumulation. The precision of the DPF carbon accumulation estimation obtained by the method disclosed by the invention is higher, moreover, parameters, the physical meaning of which is unclear, in conventional estimation methods are prevented from being used, the estimation process is quicker and more accurate, and thereby the accuracy of DPF regeneration opportunity judgment is greatly increased.

Description

technical field [0001] The invention relates to the field of after-treatment of automobile exhaust gas, in particular to a new method for estimating the carbon accumulation of a diesel particulate filter (DPF). Background technique [0002] The combustion thermal efficiency, power and economy of diesel engines are better than those of gasoline engines, so diesel engines are more and more widely used. However, due to the poorer emission characteristics of diesel engines than gasoline engines, they are more harmful to the environment. Its pollutants are mainly particulate emissions, which have a serious impact on human health. With the increasingly stringent emission regulations, exhaust after-treatment devices have become a standard configuration for diesel vehicles to solve the problem of carbon particulate emissions. Currently, Diesel Particulate Filter (DPF) is recognized as the most effective post-treatment method for diesel particulates. [0003] DPF is a filter instal...

AI Technical Summary

Problems solved by technology

At present, there are many methods for judging the timing of regeneration, such as threshold exhaust back pressure method, fuel consumption method, exhaust back pressure, speed and load combination method, but these methods have certain shortcomings, such as unreliability and complicated calculation etc., which directly affect the accuracy of judging the timing of regeneration

[0005] Chinese Patent Announcement No. CN 103016104 A discloses a method and device for calculating carbon accumulation, but the calculation process uses many correction coefficients with unclear physical meanings, and it is difficult to obtain the coefficients, which also leads to low calculation accuracy, and its The calculation process is too complicated, and the practicability is not high; Chinese Patent Publication No. CN 103511043 A proposes a method of querying the carbon load based on the engine exhaust volume flow rate and the DPF-corrected differential pressure value, but this method considers fewer factors. The accuracy of the obtained carbon accumulation data is relatively poor; Chinese Patent Announcement No. CN 104061051 A discloses a method for controlling the regeneration timing of diesel particulate traps. This method has high requirements for calibration data, and needs to set different tables for different working conditions, which is difficult to realize and has poor estimation accuracy; other patent documents lack detailed calculation methods for carbon accumulation. Most of them use the exhaust back pressure method, but there is no specific description on how to use the exhaust back pressure method to determine the carbon accumulation

Images