Simulation Study Of Lean NO_x Trap And Lean Burn Engine Modeling Based On Matlab

Faced with the problem of energy and environment becoming more and more serious,the internal combustion engine technology is required more tougher. The study found thatthe current automobile fuel tank near the2/3fuel consumption at idle condition and smallload, Therefore, whether the fuel consumption and the emission of harmful gases arederived from these two conditions.This paper establishes the model of combustiongasoline engine and exhaust gas treatment system model based on mean value model fordilute, realized in the small load condition according to the NSR working mode ofconcentrated and dilute fuel switching combustion, further explores the effect of enginespeed and load on the exhaust system, and the simulation model of delay problem, it isnecessary to practice application.There are many external load torque under idling condition,so torque and load arerequired to keep the balance of the idle condition, the more impotant is that the speed islow, So the traditional TWC can effectively control exhaust emissions. In the small andmedium of the load and speed,Gasoline engine select lean burn, The main method ofburning gasoline engine emissions of dilute NOx is the NSR at present, because thecatalyst characteristics, The requirements of lean burn gasoline engine must work betweenlean and rich combustion, which is beneficial to the fuel economy and the emissions toachieve a balance.Auxiliary ignition advance angle correction module, which makes the model ofengine speed response delay period is shortened, the engine model can be according to therequirements of tail gas treatment model, different fuel mode switching work.Using theMATLAB software to model a lean burn engine, Including air intake loop model, fuelcalculation and logic control system, power output model, tail gas treatment model andelectronically controlled EGR valve module etc.. Under the idling condition lean burngasoline engine model can be carried outstable with rotating speed and torque output andin the medium and small load by concentrated dilute conversion method of automaticswitching. The establishment of tail gas treatment can be modeled by the air-fuel ratio, thespeed and load synchronous NOx calculates the percentage of dense storage, rich and leancombustion duration ratio changes. Simulation of the change of speed and torque in thesimulation, as well as concentrated fuel lean combustion duration effects proportionalchanges on the NOx conversion efficiency and fuel consumption, through the different speed and load setting, approximate detection of exhaust gas temperature and exhaust flowreduction catalytic converter on the adsorption of conversion rate influence, and furthersimulation and experimental data of different adsorption reduction catalyst convertercharacteristic value comparison. The results showed that: Through the ignition correctionmodule supporting role model of engine idle speed fluctuations can be conditions can becontrolled in200r/min, at the same time response the shortening of the period.. strong leantorque fluctuation switch work in process (+15.6%) than the speed fluctuation (+1.5%)severe. Adsorption and reduction catalyst converter characteristic value is controlledbelow0.68S, the simulation of delay time can be controlled within10S. The engine speedand load will affect LNT transformation efficiency, load on the LNT conversion efficiencyeffect more obvious, and the speed is relatively weak.