Service manual

Alpha-N algorithm
Algorithm Alpha-N is similar to Speed Density algorithm, however the pressure in the manifold is not taken into
account, additionally the engine load is described by the opening of the throttle.
Alpha-N mode cannot therefore be used in turbocharged cars!
The formula for calculating the injector’s opening time looks the following way:
PW = INJ_CONST * VE(tps, rpm) * AirDensity * Baro * Warmup * ASE * EGOCorr * AccEnrich +
InjOpeningTime,
where,
PW (Pulse width) – is the time of opening the injectors in ms
INJ_CONST – It is a constant dependent on the engine’s capacity, size of the injectors and the Injection Divider
parameter, it represents the time of opening the injectors in order to receive stoichiometric mixture in 100%
engines volumetric efficiency, 100Kpa pressure and 21C temperature.
VE(tps, rpm) – Is the value from volumetric engine’s efficiency map displayed in percent.
Air Density – Percentage difference of air density against air density in temperature 21C.
Baro(Barometric correction) – correction of absolute pressure against barometric pressure
Warmup(Warmup enrichment) - Value of enrichment of the mixture in the function of cooling liquid temperature
ASE(Afterstart enrichment) – current value of Afterstart enrichment in %
EGOCorr(Exhaust gas oxgen sensor correction) - Correction value of the fuel dose based on the narrowband
lambda sensor is disabled.
AccErich(Acceleration enrichment) - Current value of acceleration enrichment described in %
InjOpeningTime (Injectors opening time) – injectors dead time in ms, corrected by the voltage value of the car’s
electric installation.