ZELA GTI je napisao(la):
Svuda buraz. Neko od nas dvojice se dobro zayebo, a nisam ja
ok , ako nismo ni ja ni ti onda su se zajebali inzinjeri u VW-u , imam pristup tech treningu VW-a/Scanie i Volva pa evo sta ljudi kazu , prevedi sebi
EGR is considered a `metered intake leak' and was developed to reduce the combustion temperatures to below 2,500 degrees, the threshold where NOx is created. Not unlike putting a brick in your lavatory to lower the volume of water used, the EGR valve meters a readily available inert gas (actually exhaust gas which contains a lot of very inert Carbon Dioxide) into the combustion chamber to effectively reduce the volume. Smaller effective displacement means less fire, and less heat and thus lower temperatures, thereby controlling NOx emissions.
Obviously we don't want to `reduce' the volume of the combustion chambers (effectively reduced engine displacement) during hard acceleration, so EGR is turned off when you need full power (WOT (Wide Open throttle) conditions). At idle, the engine is very sensitive to air/fuel mixture ratios and swirl in the combustion chamber, so introducing EGR at idle is not on either. However at cruise the Fuel/Air mixture is set as lean as possible for maximum economy and this in turn generates the highest temperatures, and so the EEC-V uses these conditions to inject exhaust gas into the inlet manifolds to reduce emissions
If EGR is on during idle, stumble and even stalling will likely result. If EGR is on during hard acceleration, low power (from reduced air/fuel volume) is the result. At part load, lean mixtures for economy create high combustion chamber temperatures and without EGR, these conditions not only create Nox, they also foster pre-ignition and pinking.
EGR systems are a lot more sophisticated than they used to be. With the EEC-V, they are not only monitored, but tested routinely during each `trip.' Faults are purposefully introduced to see if, and how, the system will react. If the EGR system performs outside of predetermined boundaries, a diagnostic trouble code (DTC) will be set and the Vadis/Vida will be able to read it
f the engine stumbles or stalls at idle or lacks power under load, EGR may be staying on and not shutting off. On the other hand, if the engine is pinking at cruise, EGR may not be turning on to cool down combustion chamber temperatures.
Incorrect operation could be caused by a mechanical problem such as a clogged or coked EGR valve, a ruptured EGR valve diaphragm, split or improperly routed vacuum hoses, or other component failures. All sensors that control vacuum or tell the EEC-V about engine temp, throttle position, MAP, and EGR position contribute to correct EGR function, so any of these will cause problems if they go awry. On the output side, the EGR valve itself, plus associated system components such as vacuum solenoids, vacuum valves, delay valves, and associated wiring and plumbing should all be visually and functionally checked.