Acta Technica Corviniensis

1.SORIN RAŢIU, 2. ŞTEFAN MAKSAY, 3. ANA JOSANREGISTRATION AND PROCESSINGOF FUNCTIONAL PARAMETERS VALUESFOR INTERNAL COMBUSTION ENGINESAbstract:The article represents a study regarding the creation of a correlation between the functionalparameters of the internal combustion engines, both diesel and petrol ones, with the help of theMATLAB mathematic software. The values of these parameters were registered with the help of themega macs 55 equipment, in real time, the motor vehicles running in urban traffic.Keywords:internal combustion engine, correlations, mathematic software, intelligent diagnosis, OBDINTRODUCTIONThe best results in tracking down defectsimmediately after their appearance can bereached if the motor car systems performance ispermanently supervised, which involves thedevelopment of certain on board diagnosistechniques and equipment. Their evolution hasbeen and is closely linked to the evolution ofmotor car construction. Thus, the appearance ofmicroprocessor-operated systems has enabled aconsiderable increase in the number ofobjectives monitored and the number ofregistered and analyzed parameters.The OBD (On Board Diagnostic) systemmonitors the engine performances andevacuation emissions, including the self-testsensors during vehicle running, to make sure itworks. The board computer can identify aproblem before it is tracked down by the vehicledriver, warning him/her about the failure bydisplaying a bright light. Most bright witnesseswill display “Check Engine," “Service EngineSoon" or an engine symbol.As soon as the OBD detects a problem, a failurecode (error) is registered in the motor vehiclecomputer. When the vehicle is placed on anOBD l/M checking tester, this code will help thetechnician track down and repair the defect.OBD-II is a new standard introduced in thesecond half of the ‘90, insuring the engine andchassis, equipment accessories and carinstallation control almost entirely. OBD II is anextensive set of standards used by SAE, andadopted by EPA and CARB (California AirResource Board).Certain motor vehicle models equipped withOBD-II are not 100% compatible. There are threebasic OBD-II protocols used, each with minorvariations of the communication model betweenthe board computer and scanning outrigger.Based on the OBD-II protocols, and connecting amega macs 55 tester, the main functionalparameters were registered for two types of© copyright FACULTY of ENGINEERING – HUNEDOARA, ROMANIA 45