Onboard diagnostics

The California requirements state that a vehicle must have onboard diagnostics (OBD) capabilities to receive credit for an ozone coating system. OBD is basically the system within a vehicle s computer that monitors such things as engine performance,... 

A final point to be noted in connection with the TWC catalysts involves onboard diagnostics. The EPA has stressed the need for a vehicle owner to be made aware if the auto catalyst has lost activity and needs replacement. Current efforts... 

HD engine technology is in development to meet the next round of OBD (onboard diagnostics) tightening in the US for 2013 and the new CO2 regulations in 2014. Concurrent with this, the Euro VI regulations come into play in 2013-2014. 

Hsieh M-F, Wang J (2010) An extended Kalman filter for ammonia coverage ratio and capacity estimations in the application of Diesel engine SCR control and onboard diagnostics. Proceedings of the 2010 American Control Corference, 5875—5879... 

Circuit design information Schematics, including block diagram if multiboardParts listFunctional description including onboard diagnostics (if any) Section of this... 

According to the SCR control-oriented model shown in Eq. (14.29), the key states of an SCR catalyst are SCR inlet NO(x) concentration, SCR inlet NH3 concentration, exhaust flow rate, SCR catalyst temperature, SCR-outlet NO concentration, SCR-outlet NH3 concentration, and SCR catalyst ammonia coverage ratio. Current vehicle onboard sensors are capable of measuring gas flow rate, temperature, NOx concentration, and NH3 concentration. However, the current production NOx sensors are cross-sensitive to NH3, which make the accurate measurement of SCR-outlet NOx concentration difficult. Without the information of SCR-outlet NOx concentration, closed-loop SCR control is difficult, and so is the diagnostics of SCR NOx reduction capability. Moreover, the catalyst ammonia coverage ratio ( NHa) is also hard to be directly measured. Ammonia coverage ratio is an inherent state in the SCR catalyst which directly affects the catalytic reactions. This state is... 

PMB services include all PM A items, and also include an oil and filter change, as well as more in-depth checks of the engine and drivefine. A PM B in many cases also includes a download of any onboard computer diagnostics, and action on any trouble codes or problems reported by the diagnostic system (if apphcable). 

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