OBD is the abbreviate of English On-BOard Diagnostics, interpret holds diagnostic system for the car. OBD consist in is electronic-controlled in system of benzine jet engine. What discharge code as a result of the shortage of oil natural resources and each country is increasingly strict, rely on mechanical carburettor to realize the accurate control of engine work process hard, electronic equipment be able to each segment that large-scale intervening car runs, engine management system (ElVlS, engine Management System) walked up downstage, more intuitionistic expression is the car of door of carburettor solar term was replaced by electric gush car.
Want to understand OBD to must understand EMS first. The core of EMS is ECU(Engine Contor Unit, engine controls unit) , it passes sensor of air flow transducer, rotate speed, temperature sensor, pressure sensor and crankshaft position sensor to wait for numerous sensor, real time monitors the operating conditions with complete engine, quicken the circumstance of footplate according to driver trample, according to interior beforehand the control strategy of buy controls atomizer to be in the most appropriate time (namely so called fuel injection shifts to an earlier date horn) ejective the most appropriate oily amount, make engine is lighted in optimal sky leave the job than the condition, with achieving power gender, economy is mixed discharge the unity with the most perfect sex. If dynamical system occurrence breakdown of a certain component, engine cannot work normally, cause fuel injection maladjusted, the carbon monoxide in bringing about tail gas (CO) , hydrocarbon (compound of oxygen of HC) , nitrogen (NOx) or fuel evaporate one of polluting a quantity or multinomial discharge exceed bid, even engine cannot move.
OBD exceeds bid to discover tail gas is discharged in time namely and find engine report quickly to accuse what systematic breakdown is in and be born. Should appear breakdown, discharge when exceeding bid, breakdown caution light can twinkle, remind a car advocate go maintaining a station to overhaul car.
From 20 centuries 80 time rise, the electric in season that business of each automobile factory of beautiful, day, Europe begins to be produced in its deploys OBD on the car. Because of its as a result of each OBD system EMS differs and each are not identical, the diagnostic interface that they use proper motion to design severally reachs the breakdown code that defines oneself, department of car of avery kind of has one to cover special detect tool, detect to maintenance bring very big inconvenience. Earlier OBD is right itself data cannot self check, make the car after maintenance often the technical requirement of short of former plant. To solve this problem, association of American car engineer (SAE) raised OBD-II standard standard 1994, of its use standard detect program, need not use special tool, offer unified diagnostic mode according to OBD-II standard, want to an instrument can pass unified interface to undertake detecting to all sorts of cars only, those who give the whole world is electronic-controlled vehicle maintenance and repair offerred huge to go to the lavatory.
Previous12 Next
