Petr píše:To mi nekdo chce tvrdit, ze uzavrenim paliva ridici jednotkou vznikne chuda smes ?! Ano, mozna na pul vteriny, nez motor spali co je ve valci .. a tohle propali pisty ? no tak to je snad velka blbost.
A propo kdyz jedu z kopecka, sundam nohu z plynu , je znamo, ze strikacka uzavre vstriky a jedu tak s nulovou spotrebou.. chcete mi rict, ze tak taky propalim pisty ? to snad neee
Rekl bych, ze je rozdil chuda smes a ZADNA SMES .. Spadne li podtlak z regulatoru tlaku, potom je problem, protoze smes je chuda... ale vypne-li se privod uplne, smes neni zadna a motoru prece nic nehrozi
Takze tuhle vec skutecne jen zbytecne nafukujete
krom rizika cukani pri predjizdeni tady nic svetoborneho ve fuelcut nespatruji
No aj mojou vinou tu vzniklo par omylov, takze to skusim napravit:
Takze pekne po rade:
1,Nikto nepise ze fuelcut musi byt pri rychlostiach 200km/h a podobne.Fuel cut nastane vzdy ked dosiahne vystupne napatie na AFM 5V a to moze byt pri akejkolvek rychlosti, zavysi to len od tlaku turba a spotreby vzduchu v motore.Dolezite ale je ze nastane PRI PLNOM PLYNE! Takze mas plny plyn, turbo tlaci 0.8bar a auto dosahuje svoje maximalne zrychlenie.A teraz sa ti vypne privod paliva.Ver tomu ze to trhne a to poriadne.Moja informacia o chudobnej zmesi pri fuel cut bola ale chybna, pokial je fuel cut prevedeny spravne, nic sa nestane, tu je popis:
Fuel Cut
The idea of cutting fuel to an engine sets alarm bells ringing in engine builders, as they all know of the potential disaster of a high revving race engine running lean. Running in a lean combustion mode will elevate in-cylinder temperatures very rapidly, the denser the air/fuel charge, the more heat the lean burn can generate. Therefore it is vital that a fuel cut system will not cause a lean burn.
The simplest way of preventing a lean burn is to remove more than 50% of the fuel from the pulsed delivery. A mixture will only ignite if the air/fuel ratio is within a tightly defined window, look at the efforts being put into making lean burn engines fire on very low air/fuel ratios (1:20 or more). Removing more than 50% of the fuel will cause an air fuel ratio of over 1:25 and will result in a complete miss-fire, with the unburned fuel passing out through the exhaust valve. Even if a high air/fuel ratio did manage to ignite, the energy available from the amount of petrol injected wouldn't be enough to elevate temperatures significantly. Of course the ideal system will remove 100% of the pulsed fuel delivery, allowing the cylinder to take a gulp of fresh air, and the in-cylinder temperature would remain virtually unaffected.
Prolonged fuel cut on one particular cylinder would cause scavenging of the petrol lining the inlet tracts, and when the next full fuel pulse arrived, it would be partially reduced in quantity by the re-wetting of these tracts. Therefore it is often important to manage a rotation of the cylinder cutting to prevent this situation from occurring.
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Spark Cut
Cutting the spark to an engine will stop any chances of a weak mixture occurring, but it carries it's own potential problems due to a large quantity of unburned fuel travelling through the cylinder and out of the exhaust. This petrol can remove some of the oil lining the inside of the cylinder, and pass it thorough the exhaust, again this only becomes a problem if the fuel to one particular cylinder is cut for an extended time. The best way to overcome this is to rotate the order in which the cylinders are cut.
The unburned fuel in the exhaust will have a catastrophic affect if there is a catalytic converter in the exhaust, as it will try to convert the unburned fuel to harmless elements, effectively burning the mixture. This causes the catalytic converter to heat up very rapidly, reaching temperatures in excess of 1000°C, and possibly melting down completely. Thus prolonged spark cut is not recommended for catalytic equipped cars.
Ci staci pol sekundy na prepalenie piestu pri chudobnej zmesi?Tak tomu ver ze staci......
2, Ked pustis plynovy pedal, tak samozrejme ze sa vstreky nezavru a ze spotreba nie je nulova
Motor bezi na volnobehu, mnozstvo vzduchu je dane otvorenim volnobezneho ventilu a k tomuto mnozstvu vzduchu sa vstrekuje adekvatne mnozstvo paliva, ako nakoniec vzdy. Samozrejme ze nemas nulovu spotrebu, motor potrebuje palivo aj na volnobeh, nie?
nulovu spotrebu mas ak vypnes zapalovanie, ale to zas nejde motor:))
3, obmedzovac otacok:funguje tiez na princpe fuel cut, vypina sa privod paliva (je mozne urobit aj obmedzovac na principe spark cut, vid vyssie)
4, standardne je obmedzovac otacok nastaveny na 7200ot., ak sa nemylim.V mojom stage3 chipe je to 7600ot.Ale rozhodne nevidim dovod tlacit motor do obmedzovaca, kedze max.vykon je niekde v oblasti 6500ot...
5,Odstranenie fuel cut je potrebne preto, ze pri adekvatnych upravach motora (FMIC,vyfuk,tlak turba) a hlavne ak je chladno znamena plny plyn pri cca 4000ot velku pravdepodobnost vypnutia paliva, co asi jazdu nesprijemnuje.Opakujem vobec to nemusi byt pri 200km/h, zavysi to len od tlaku turba a spotrebe vzduchu v motore (alebo inak od priechodu mnozstva vzduchu cez AFM).
Ak by niekto mal zaujem len odstranit fuel cut so standardneho cipu, bez problemov urobim, ale nie je to dobry napad, pretoze tu uz hrozi realne chudobna zmes...
Zhrnutie:
fuel cut nesposobuje chudobnu zmes (Raddy sa ospravedlnuje
)
fuel cut sa aktivuje v zavyslosti od zataze motora, nie rychlosti a otacok
fuel cut je nutny pri seriovom cipe, pretoze seriove palivove mapy nerataju s mnozstvom vzduchu vacsim ako je schopne namerat seriove AFM (5V je pri vykone cca 190-200k) a ak by sa dalej zvysovali otacky, ECU by nedoakzala korektne kalkulovat mnozstvo paliva.
riesenie:Stage 1 chip, kde nie je fuel cut a mapy su ratane az po obmedzovac (nie naozaj ale zhruba pre vysvetlenie, hlavne je ze to funguje:)) tak povediac za roh schopnosti merania AFM.
Aloha a nech moja karma rastie umerne dlzke mojich prispevkov:)
takže prodávám sv?j ?ip STAGE 1.
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