Study On The Influence Of Lubricating Oil Ash On Catalytic Gasoline Particulate Filter Performance

As the number of cars in our country increases year by year,environmental pollution has become more and more serious.The gas and particulate pollutants emitted by cars have a serious impact on people’s lives and health.At present,gasoline engines mainly use a combination of incylinder purification and external after-treament system technologies to solve their emission problems.The catalyzed gasoline particulate filter(CGPF)in the after-treatment system is considered to be a key technology to solve the problem of gasoline engine gas and particulate matter emissions.However,during the use of CGPF,the ash produced by the combustion of lubricating oil has an impact on its overall performance.This paper was based on the rapid aging method of the blending of lubricating oil and gasoline.Firstly,the CGPF was quickly aging,and then the effect of ash on the back pressure of the CGPF and the engine power performance and fuel economy was studied on the engine bench.Finally,the influence of ash on vehicle emission performance was studied under WLTC operating conditions and the Real Drive Emission operating conditions.In this paper,based on the rapid aging method of mixed burning of lubricating oil and gasoline,five CGPF samples were loaded with different ash content on the engine bench,and the ash deposition morphology in the CGPF was studied by computerized non-destructive tomography.Studies have shown that ash is mainly deposited at the end of the carrier,especially in the center,in a mountain-like shape.Then,through the engine bench,the influence of ash on the engine exhaust back pressure,torque,power,and fuel consumption rate at different speeds was studied under the external characteristics of the engine.Studies have shown that CGPF back pressure increases with the increase of engine exhaust flow and ash content,but the increase in back pressure caused by ash content is not enough to have a greater impact on engine power performance and fuel economy.The catalytic gasoline particulate filter is coated with a catalyst on the traditional CGPF,which is beneficial to reduce the emission of gas pollutants.In this paper,the influence of ash on the gas conversion efficiency and oxygen storage capacity of CGPF was studied on the engine bench.Studies have shown that ash accumulates in the CGPF channels and covers the surface of the catalyst coating,leading to an increase in the light-off temperature of CGPF,and the impact of a small amount of ash accumulation in the early stage is greater than that in the later stage,but the maximum gas conversion efficiency is less affected.At the same time,related elements in lubricating oil cause catalyst poisoning,and the oxygen storage capacity of CGPF also decreases with the increase of ash content.Finally,a certain vehicle that meets China’s sixth stage emission regulations was used to study the impact of ash content on the vehicle’s emission performance.Under WLTC conditions,the emissions of vehicle gas and particulate matter are mainly concentrated in the first stage,of which the proportions of HC,CO,and PN in the first stage are respectively 93%,81%,and 90%.Consistent with the bench test results,the accumulation of ash will also lead to an increase in vehicle gas emissions.However,the Real Drive Emission operating conditions did not reflect a large difference due to the influence of various factors in the external environment.However,vehicle benches and the Real Drive Emission tests have shown that ash accumulation is beneficial to reduce the emission of particulate matter PN,and a small amount of ash can significantly improve the filtration efficiency of CGPF on PN.