THE ELECTRONIC CNG DISPENSER SYSTEM IS DESIGNED TO CONTROL AND MEASURE CNG QUANTITY DELIVERED TO VEHICLES WITH TEMPERATURE COMPENSATION TO ENSURE THAT VEHICLES ARE ALWAYS ACHIEVED COMPLETE FILL.IN ORDER TO MAKE THE UTILIZATION OF THE STATION COMPRESSOR AND BUFFER STORAGE MORE EFFICIENT, THE SYSTEM WILL OPERATE USING A THREE-STAGE “CASCADE” BUFFER SYSTEM. THE BUFFER STORAGE IS DIVIDED INTO THREE “BANKS”: LOW, MEDIUM AND HIGH-PRESSURE BANKS.WHEN THE VEHICLE IS FIRST CONNECTED TO THE DISPENSER, THE SYSTEM WILL MEASURE ITS CYLINDER PRESSURE (P VEHICLE). USING SPECIAL ALGORITHM, A NEW TARGET PRESSURE (P TARGET) WILL BE CALCULATED AND USED TO CONTROL THE REFUELING OPERATION. IF P VEHICLE IS LESS THAN P TARGET THE SYSTEM WILL START THE REFUELING AND OPEN THE LOWBANK VALVE. AS THE PRESSURE IN THE BANK FALLS AND THAT IN THE VEHICLE CYLINDER. RISES, THE FLOW OF CNG DECREASES. WHEN THE FLOW RATE HAS DECLINED TO A PRE-SET LEVEL (MINIMUM FLOW) OR AN INTERVAL OF TIME PASSED (TIME OUT) THE SYSTEM SWITCHES TO THE MEDIUM PRESSURE BANK, THEN FINALLY TO THE HIGH-PRESSURE BANK. TO COMPLETE THE FILL.ELECTRONIC SYSTEM CALIBRATIONTHE ELECTRONIC SYSTEM HAS AN INTERNAL CALIBRATION FOR THE ANALOGUE INPUT MEASUREMENTS. THIS CALIBRATION WILL BE DONE IN THE TESTING PHASE AND BEFORE SHIPPING THE CONTROL SYSTEM. THIS CALIBRATION WILL BE DONE ON THE IO SUBSYSTEM BOARD AND VALUES ARE STORED IN THE CONFIGURATION PARAMETERS AT CONTROL BOARD. THE CALIBRATION HAS TO BE CHECKED AFTER ANY SERVICE ON ANY OF THE TWO BOARDS.DISPENSER CALIBRATIONSTANDARD WEIGHING CALIBRATION WILL BE USED FOR THE DISPENSER CALIBRATION. THE PARAMETER [13][CNGD] MUST BE CONFIGURED WITH ACTUAL CNG DENSITY.
/11117-320x220.jpg)
