Ok, vērsim pie ragiem - ir auto, principā 2 gabali ar ieswapotiem 1.8T AEB dzinējiem un uzliktu ME7.5 vadību. Problēma - auto tukšgaida purinās un @part throttle iet labāk kā @WOT. Viss atpas izņemot galvu un ieplūdes kolektoru (teorētiski arī sprauslas, bet to var izslēgt, jo vienam no auto ir uzliktas vadībai atbilstošās sprauslas) - AEB ir lielāki porti galvā, resnākas stabules kolektoram un iespējams lielāka kolektora krājtelpa. Piezīme: visiem ar ME7.5 vadītajiem dzinējiem ir mazāki porti galvā un šaurākas stabules kolektoram.
Izvirzītā teorija - dēļ lielāka galvas kanālu un kolektora tilpuma, kā paredzēts vadībā, telpā no droseles līdz vārstam (kam ME7.5 vadībā ir savs paramters/funkcija) ir mazāks gaisa spiediens, ka arī dēļ šaurākām kolektora stabulēm ir mazāks plūsmas ātrums, kas rezultējās mazākā cilindru aizpildijumā nekā to paredz/sagaida vadība. Konkrētās telpas spiediens un aizpildijums netiek mērīti, tie tiek rēķināti ņemot vērā diezgan garu sarakstu ar parametriem un kartēm.
Teoriju gandrīz pilnība apstiprina šodien izveiktais eksperiments uzliekot dzinējam ieplūdes kolektoru ar mazajām stabulēm. Dzinēja darbība uzlabojās, bet ne līdz galam. Te, visticamāk, nospelē fakts, ka galvas kanālu tilpums still ir lielāks kā domā vadība.
Uzdevums - atrast nepieciešamās kartes, konstantes, parametrus, kas atild par telpas tilpumu, tos pārrēķināt lai atbilstu reālajiem un izlabot programmu.
Tā kā ME7 vadība man nu jau gandrīz gadu ir aktuāls temats, esmu ievācis nedaudz informācijas un materiālu par ta darbību. Ir pieejams VAG R4 ME7.5 pilns funkciju apraksts vāciski un Alfa Romeo ME7.4 apraksts angliski. Laika gaitā ejot cauri konstatēts, ka lielākoties visas funkcijas abiem ir identiskas, tad principā Alfas dokumentāciju var izmantot lai saprastu čo pa čom jo vāciski es māku tikai lamāties, lasīt shēmas un s**g h**l.
Parskrienot cauri dokumentācijai, šķiet, ka mums aktualā funkcija varētu būt BGSRM - Model of intake manif. for calc. relative air charge and intake manif. pressure
Screenshotā redzamas divas no funkcijas shēmām, tālāk dokumentācijā ir atrakstīti arī visi paramteri, bet par to vēlāk.
Funkcijas apraksts stāsta:
The intake manifold model calculates the air charge in the combustion chamber from the air mass flowing into the
intake manifold.
An integrator simulates the storage of the intake manifold. It integrates the difference between the in-flowing relative
charge rlroh and the extracted relative air charge rl using the integrator constant KISRM, and delivers the standardised
air mass in the intake manifold at its output. The integrator is calculated in synchro. This acts like a multiplication of
the input variables by the engine speed. If the relative charges are used instead of the air mass flows as input signals, the
result obtained at the output is an intake manifold air mass.
With the temperature correction factor ftsr and the value for standard pressure 1013hPa the partial intake manifold
pressure of air mass and internal residual gas at a given air mass temperature in the combustion chamber is calculated from the
air mass. With an external EGR system, the partial pressure agrp w, generated by the external EGR, is added on. This produces the
total intake manifold pressure, which represents an important intermediate variable for other functions.
With the engine extraction equation rl = (ps - pirg) * fupsrl)*(100%-agrr) the extracted relative air charge rl is calculated from
the intake manifold pressure. In this way the relationship between the air charge rl and the intake manifold pressure
can be described by a straight line, calculated from the offset pirg and the slope characteristic starting value KFPSURL.
With active exhaust gas recirculation (EGR) the total charge signal rfges is corrected to the relative air charge rl by
multiplying-in the EGR rate.
The offset is interpreted as residual gas pirg, which remains in the combustion chamber. The offset is dependent on the engine
speed nmot and the overlap angle wnwue at systems with camshaft control. If the camshaft position is between the two extremes of
camshaft control, offfset value pirg is calculated by linear interpolation as function of wnwue.
As the ambient pressure falls, the proportion of residual gas falls. The offset is therefore reduced by the altitude factor fho.
The slope of the straight line at standard temperature is also dependent on the engine speed and the overlap angle wnwue at systems
with camshaft control. The slope is calculated by the same method as the offset. For calculation of the intake manifold
pressure ps to the relative airr charge, the current air temperature in the combustion chamber must additionally be taken into
account. This is done using the factor ftbr. The faktor fupsrl = ftbr * KFPSURL takes into account all influences on the slope in
translation of pressure into air charge. The factor fupsrl is also provided for other functions.
With an external EGR system the calculation from intake manifold pressure to air charge delivers the total charge rfagr including
the EGR portion.
The extracted air mass rl is reduced by the EGR rate agrr. Then: rl = rfagr * (1-agrr).
rl is fed back to the input of the integrator as the extracted air charge. rl is the central variable for calculation of the
injection. The extracted air mass flow ml is obtained from the product of engine speed, rl and the constant KUMSRL.
The incorporation of the EGR partial pressure into the intake manifold model allows for calculation of the EGR portion of the
combustion chamber charge with the appropriate timing. The associated integrator for simulation of the storage behaviour of the
intake manifold referred to the EGR charge is to be found in the function BGAGR.
Ļoti pieļauju, ka visproduktīvakais variants būtu savākties pie kāda alus tilpuma un ņemot talkā skaitļošanas tehnikas vienību kura glabājās abas vadību dokumentācijas un apspriest šo visu, bet bring it on. Pieiesim problēmai no pareizās puses, jo uzpogāt dzinējam mazo kolektoru un mazo portu galvu būtu so diesel
(c)mdz