Mecanica maquinaria pesada
Mecanica maquinaria pesada gy josephhuilcapaz I ACKabpR 03, 2010 4 pagos Auto calibration The process of auto calibration has the purpose to set all the parameters of LPG injection steering. It uses the advanced technology of engine data transmission which are agreeable with the OBD II/EOBD protocol. Measuring the air and fuel flow during dnving on two fuels (separately on petrol and LPG) it sets the MULT. factor. A precise selection of the MULT. factor guaranties the same air-fuel quality on petrol and on L PG. The correct auto alibration requires the correct selection of the LPG injector.
Selecting the injector type you auto calibrate the producers settings of the injection characteristics. Each injector has its own dependence of the injection dose from its opening time. The Iower is the resistance of the coils so bigger is the magnetizing of the construction elements and the closin of the injector is Sw p to p age delayed. Similarly, th expense causes t hec ng the injector. That’s w irs R right injector constru the calibration proce ora R ng the injectors me and closing of T to correctly chose before you start _ fier choosing the injector we proceed to starting the auto calibration procedure.
The key is on th the chart CALIBRATION-> F8 Correction map->F10 Auto calibration. Next we press the key (see drawing below). The calibration procedure consists of three steps: In the first Step we find the injection time on petrol and L PG on idle drive with the RPM between 2000 and 3000. In the second Step we make the drive on petrol so that: • the RPM is over 2000 and under 5000, • the petrol injection time is bigger then than its double value n idle drive, but not bigger than the five times the value on idle drive, • when irs possible to hold the throttle in on position for a few seconds (settled state).
In the third Step we make the drive on LPG and we try have similar conditions like above. Switching over between the fuels (petrol/LPG) is done automatic by the LPG ECU. The auto calibration procedure chooses the LPG injection characteristic. The first approximation of the MULT. factor is done on idle drive by 2500 RPM. When the MIJI_T. factor is much different from it on idle drive the procedure is automatically one again. The calibration is continued to the moment, when by adjusting the LPG injection characteristics the petrol injection time during driving on LPG are equal to the values during driving on petrol.
In the firs Step of auto calibration we collect five points on petrol and five points on LPG. The RPM and the load have to b calibration we collect five points on petrol and five points on LPG. The RPM and the load have to be in the allowed area. You can see that as the green OK signs. Crossing the allowed area Will cause the appearance of a red signs («to little», «to The points measured on petrol are marked by red Dotson the load diagram m[%] – petrol injection [ms], and the points measured during wo kon LPG are marked as green dots.
Reside that on the screen you can see long- and short-term summary corrections of the petrol injection and the lambda probe progress. After ending idle drive you should start the calibratlon drive – you Will see the proper communiqué on the screen. After holding the proper work conditions of the engine points on petrol start register. After registering five good points on petrol the system switches over to LPG. When the dispersion of points on petrol is to big the system collects additional points on petrol until it has five good points (which are placed near the line ofthe petrol injection characteristic).
The number of good points and the summary number of registered points is given on the screen. Wrong (much different from other) points are caused by the to quick move of the throttle. After finding the good ones the points during the drive on LPG start to register. When the characteristic of th 3Lvf4 ones the points during the drive on LPG start to register. When he characteristlc of the LPG injection is right green point show up near the straight line made by the red ones.
When the calculation petrol/l_PG is to big, the injection of petrol WII be made shorter green dots are to Iow. When the calculation petrol/LPG small the petrol injection Will be made longer — green dots are to high ( see drawings below). After checking that that the petrol injection is OK during driving on LPG the system decides to end the calibration procedure (the calibration ended successfully). When the next (good) five points on LPG aren’t found to the efficient end. When the MIDAS OBD interface is not connected the auto calibration procedure has small changes.
First of all in stead of five only one significant point is registered during the dnve on petrol. After starting the drive you should disperse the car so you have a stabile RPM and press the pedal to the end. When the petrol injection times are stabile this injection is registered and the system starts the measuring procedure on LPG. You also should during idle drive avoid switching on any devices that use energy (for example the fan) they disfigure the length ofthe petrol injection.