Study On Control Of Diesel Engine Through Closed Loop Control Based On The In-cylinder Pressure

The technology of close-loop control based on in-cylinder pressure is used to controlcombustion characteristic parameters CA50, IMEP and so on,which according to the targetvalue operation. This technology is used to control the HCCI combustion mode,making thecombustion process more stable.According to this view, the cylinder pressure feedbackcontrol technology applied to the traditional diesel engine combustion mode, exploring thepossibility of applying this technology to reduce the fuel consumption and emissions.To achieve the research object,the RapidPro of the diesel is built,and the engine couldbe operating normally.The benefit of applying dSPACE to build a real-time simulation is thatthe control program can be easily changed, and it is also convenient for adding new modelssuch as close-loop control of the combustion parameters. New methods and new ideas can bevery easily be verified during the test. is equivalent to the sensors of CA50, IMEP, Pmax andother characteristic parameters. The6052-type non-water-cooled sensor of Kistler Companyis used as the cylinder pressure sensor. There is an thermodynamic algorithm in the programof the combustion information feedback unit can eliminate errors caused by zero drift,andthe measurement results fully meet the test requirements through the verification of the AVLcombustion analyzer.After creating the platform of close-loop control based on in-cylinder pressure, theproblem of unevenness between different cylinders is studied.The results showed thatinjection timing, rail pressure, intake air, manufacturing errors and wear can significantlyaffect the degree of heterogeneity between different cylinders.Using the the technology ofclose-loop control of CA50and IMEP, the degree of heterogeneity between differentcylinders can be well reducd. Evaluated by the CoV, CA50_CoV lower than90%,IEMP_CoV reduced by more than60%. The study also found that there is no significantimpact to the fuel consumption and emissions of the engine after the unevenness betweendifferent cylinders significantly reduced. One reason is that heterogeneity of the originalmachine is in a better level,so the reason of high fuel consumption and emissions is notmainly caused by unevenness between different cylinders.Exploring how to use the cylinder pressure feedback technology to reduce fuel consumption and emissions in the steady-state and the transient conditions is the coreresearch topic. It is proved that in the stable experiment condition, the technology ofclosed-loop control could not achieve the purpose of reducing fuel consumption andemissions at the same time.The process under the transient operation of constant speed andincreasing torque of the turbocharged disel engine,due to the slow response of theturbocharger,cased gas shortage and the instantaneous fuel consumption increases.This paperaims to use the technology of close-loop control based on in-cylinder pressure to find acontrol strategy of reducing the fuel consumtion without changing the turbocharger.Theoperation experiments of delaying CA50show that the control strategy can improve theindicated thermal efficiency by1~1.5%,NOx transient emission decreased by7%atleast,while the soot emission can be kept no increase.