Emissions slides - Stop 5: 60 10 mm a. 40 E 20 O u 300 600...

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Unformatted text preview: Stop 5: 60 10 mm a. 40 E 20 O u 300 600 900 1200 1500 1800 2100 LPhase |*L——- Phase ll M! L- Phase Ill *L—S US - 72 Cycle: US - 75 Cycle Breakdown: Breakdown: Length: 7.5 mi Length: 11.09 mi Time: 1371 s Time: 1877 + 600 5 Av. vei: 19.7 mph Av. vel: 21.3 mph Max. vel: 56.7 mph Max. vel: 56.7 mph idle: 17.4% ldle: 17.3% Steady speed: 20.0% Steady speed: 20.5% Acceleration: 34.0% Acceleration: 33.7% Deceleration: 28.8% Deceleration: 26.5% US - 72 Test: US 75 Test: Cycles/T est: 1 Cycles/T est: 1 Test lengths: 11.09 mi Test lengths: 11.09 ml Test time: 1371 5 Test time: 1371 s + (600 5 Cold start test procedure stop) + 505 3 Exhaust emission analysis in 2 The US-75 test is an expanded US- bags: Bag 1: 0-505 3, 72 test. The first 505 s of the cycle Bag 2: 506—1371 s will be repeated after a 10 min stop Calculation of the fuel confisump- at 1371 5. Calculation of fuel tion derived from the emissions consumption is derived from the emissions. The emission sampling is in 3 bags: Bag 1: 0-505 5 (43%), Bag 2: 506-1371 s (100%), Bag 3: 0—505 5 (57%) after the 10 mins. stop Recorders 5 @ I _ l l HC:CO Analyzers Vent Exhaust gas samlDle bag Volume counter Heat exchanger Driver aid Exhaust Dynamometer ‘ Heated To amb'em To background sample line particulate sam [6 ba sample g Hea‘ed lnte rator Mixmg Heated robe orifice sample p T Heated Primary ""9 FID Dimfion dilution and Heat - - tunnel PrObe exchanger T0 EXhaUSt air filter sample bag V Ambient (3‘) fil- - T air inlet § ""3 Continuous @ <—— Discharge measurement NOX, CO, CO2 I t <— Particulate transfer lube To secondary Back-up filter dilution tunnel Mano Gas meter Fmer Pump Gas meter ' Secondary a 6 Discharge dllutlon "‘ s --:;-||-£ “ Inlet a Secondary 7 Mano dilution tunnel Flame Ionization Detectflr (FIB) E—Il' ['ILT‘T‘HII measuring: Ea uirruilmmfipnndfi In E inns crgatcd cflmbustiun in tin: flarnt. Flume Air Flmr In _ _ + nil-mm IIIlel Cnlumn input {and (1f Eniumn} ItlSlJlfltEf'i Exit Gases Emma than 1; Insulated tn Collector ‘ Cane ctur E13 Ctr" '13 \ Ele ctrn dB 5 Flame Insulatiflll Insulated J at Insulated ~——"l"' Carine ctinn Insulation to J at —I- Hydra gen l capfllfil'fi’ Cfllmfm Air or nygen Carrying M01313 l for Combustion Phase [Helium] | 1.0" 0... SD" ASl ASl 2.0° ASI O—‘g 3.o° 6.5° ASl O‘Q ASl 4.00 8.0” ASI ASl 4.5° ASI O 10 20 H: Scale (mm) - Liquid fuel _ PAHs _ Low . High i:l Vapor-fuel/air mixture Diffusion flame soot concentration (equivalence ratio 2-4) Chemiluminscence emission region Figure 9-17 Detailed model of diesel combustion (Dec, 1997). Reprinted with permission © 1997. Society of Automotive Engineers, Inc. ' '0'116 Mole fractions C0, C02, 02, H2 N0, CO, and HC concentrations (not to scale) A00 X+c1 0114 0.12 .0 S 0.08 .o 8 _o E 0.02 0.00 20 0.7 H&S I ’ St,Sp n ‘ 0.8 07 03 . 1.0 ' 1.1 2 1.3 1. 1.5 Exhaust equivalence ratio O‘mfifi—fiW—A—Ifil—l—l—fi o.14—- ’9 — 030* a 0.12— “0 :1 a I; if X 8 0.10— 3 X00 .1 8 008* E —‘ EA - x X xao .; o :5 0.06'— 0.“: A ~ .9 >9 . . ' g 0.041— c0: * ° — Alt/fuel rat1o x29 17 15 14 13 12 O_02_ d _. Stoichiometn’c 0.9 I .0 l . l 1 .2 l .3 Fuel/air equivalenca ratio Exhaust equivalence ratio co } 0.m'——L~&&WQ_HW—§Ja—l——Io 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.3 0.9 1.0 Deposits absorb HC 3“ N0 (“mm in C0 present at high4cmpcmiurc high temperature and if fucl rich End gas source of HC if combustion incomplete Oil layers Unbumed absorb HC mixture forced into crevices (a) Compression (b) Combustion As burned gases c001, Deposits desorb HC first NO chemistry, then CO chemistry freezes Entrainment of HC from wall into bulk gas Oil layers desorb HC Outflow of HC from crevices; Piston some HC i ‘7 h scrapes burns .. HC ofl" walls (6) Expansion (d) Exhaust FIGURE 11-1 Summary of HC, CO, and NO pollutant formation mechanisms in a spark-ignition engine. Lean flame-out I“itile rapid region: HC combustion: noise Burned gas: N0 Fuel jet mixing with air: rich mixture Premixed White/yellow flame: Burned gas; No 800! OxidatiOn Rich zones in fuel jci; soot formation Flame quench on walls: HC FIGURE 11-3 Summary of pollutant formation mechanisms in a direct-injection . from nozzle compression-ignition engine . . Sac volume during “premixed “ and “ mixing- Mixmg controlled controlled " combustion phases. Fuel vapor Metal mesh Shell Catalyst Converter shell Insulation Outer wrap Retainer Inlet gas Catalytic pellets Outlet gas 0?) FIGURE 11-53 Catalytic converters for spark-ignition engine emission control: (a) monolith design; (b) pelletized design.62 Catalyst efficiency, % 100 Catalyst conversion efficiency, % 100 80 ON C 4; O 20 0 14.3 80 60 4O 20 Q‘s/r r l 0 HC I l J. 200 300 400 500 Temperature, °C 80% efficiency air/fuel ratio window ' Stoichiometric air/fuel ratio l I 14.7 14.8 Lean Air/fuel ratio I I. ,. I I I I I : I I I I l I I I I I 14.5 14.4 14.6 Rich FIGURE 11-54 Conversion efficiency for CO and HC as a function of temperature for typical oxidizing catalytic converter.62 FIGURE 11-57 Conversion efficiency for NO, CO, and HC for a three-way catalyst as a function of exhaust gas air/fuel ratio.68 14.9 TABLE 11.11 Possible NO reactions under reducing conditions68 1. NO + CO —> g-NZ + C02 2. 2N0 + 5C0 + 3H20 —+ ZNH3 + 5C02 3. 2N0 + C0 -+ N20 + C02 4. NO + H2 ->—§-N2 + H20 5. 2N0 + 5H2 —> 2NH3 + 2H20 6. 2N0 + H2 —+ N20 + H20 'Reactions 3 and 6 occur at 200°C, which is below that usually found in auto exhausts. ...
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Emissions slides - Stop 5: 60 10 mm a. 40 E 20 O u 300 600...

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