On-Board Diagnostic

Continuous measurement of OSC of the catalyst inserted in the converter is one of the simplest tool to monitor catalyst efficiency. This is known as the On-board diagnostic (OBD). Sideris has recently reviewed the OBD technologies on the basis of the corresponding patent literature [103]. Even though other techniques are available (temperature sensors, specific sensors for CO, HC and NOx), OBD determined by means of O2 sensors remains the technique the most widely employed in car industry. This technique is based on the generation of periodic rich/lean perturbations monitored by two lambda sensors, one located upstream and the second downstream the converter. Catalysts that have good OSC considerably attenuate the upstream perturbation (with a significant time lag) while virtually dead 

Taha et al. [104] have compared the effect of thermal aging on both OSC values and catalytic performances. Two commercially available catalysts were selected Cat 1 Pt-Rh (0.152%Pt-0.031%Rh on a wash-coated monolith containing 6.3% Ce and 0.66% La) and Cat.2 Pd-Rh (0.19%Pd-0.022%Rh on a wash-coated monolith containing 4.6% Zr, 1.9% Ce and 0.9% Ba). These catalysts were aged in N2+H2O at 900,1000 and 1100°C or in an engine-bench for 25, 50 or 200 h. OSC of the fresh catalysts were 91.8 (Pt-Rh) and 59.7 pmolO.g (Pd-Rh) respectively. OSC changes with aging parameters are shown in Fig. 7.15. 

The catalytic activity for CO, HC and NO abatement was measured at 450°C in a synthetic gas which simulated reactions conditions around the stoichiometry (1 Hz, amplitude, 0.05). Conversions versus OSC are shown for the two catalysts on Fig. 7.16. 

Similar results concerning the sensitivity of NOx conversion to aging were obtained by Permana et al. [105] who showed, however, that the use of a wash-coat loaded with Ceo.75Zro.25O2 permitted to maintain a much better performance than with pure ceria. Many attempts have been made to improve OSC properties and catalytic activity in modem TW catalysts. It seems that the incorporation of an extra Stabilizer allows to reduce the ceria content while maintaining very high 

Colon G., Valdivieso F., Pijolat M., Baker R. T., Calvino J. J., Bernal S., Catal. Today 999), 271 

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On-Board Diagnostics. State of California regulations require that vehicle engines and exhaust emission control systems be monitored by an on-board system to assure continued functional performance. The program is called OBD-II, and requires that engine misfire, the catalytic converter, and the evaporative emission control system be monitored (101). The U.S. EPA is expected to adopt a similar regulation. 

W. Clemmens, M. Sabourin, and T. Rao, Detection of Catalyst Failure Using On-Board Diagnostics, SAE 900062, Society of Automotive Engineers, Warrendale, Pa., 1992. 

On-board diagnostic (OBD) function, 70 38 On-board diagnostic system (OBD-II), 70 57-58... 

All detectors need to be verified for meeting their noise and drift specifications. These tests are often performed with a dry cell that is sealed and has no actual solvent flow going through it. Some detectors have on-board diagnostics for these tests, with digital performance readouts. 

Konstandopoulos, A. G., and Kladopoulou, E. A Virtual Sensor for On-board Diagnostics and Control of Diesel Particulate Filters . CDAuto03A2028, CD AUTO 03, 4th International Conference on Control and Diagnostics in Automotive Applications, Sestri-Levante, Italy, 2003, June 18-20. 

On-board diagnostics lo aid in troubleshooting and isolating and identifying failures. 

N. Pollings and co-workers, A Unear Catalyst Temperature SensorfiorExhaust Gas Ignition (EGI) and On Board Diagnostics of Misfire and Catalyst Efficieny,... 

The type approval regulations also lay down rules for in-service conformity, durability of pollution-control devices, on-board diagnostic (OBD) systems, measurement of fuel consumption, and accessibility of vehicle repair and maintenance information. 

In addition to the adoption of a Low Emission Vehicle/Clean Fuel program, the California Air Resources Board (CARB) has adopted regulations which call for comprehensive on-board monitoring of seven components and/or events related to emissions of exhaust, fuel, and air conditioning heat-transfer agents for vehicles sold in California. This legislation is called "On-Board Diagnostics-Phase II" or "OBD-II" [30]. These systems were installed on all vehicles sold in California in the 1996 model year. The Environmental... 

AECC supports the implementation of improved Inspection and Maintenance programmes for Europe and the requirement that On Board Diagnostic Systems be installed to monitor the operation of the engine management and emissions control components, including the conversion efficiency of the catalytic converter. This is important as the performance and dmability of the catalytic converter are very dependant on the systems of which it is a key part. 

Two commercial catalysts (PtRh and PdRh) were treated in N2+H2O (or Air+H20) at 900, 1000 or llOO C (Lab. ageing) or aged on an engine bench for 25, 50 or 200h. OSC (transient CO oxidation) and catalytic activity for CO, HC and NO abatment Oight-ofif temperatures and conversion at 450°C) were measured over these aged catalysts. Correlations between OSC values and catalytic activity are discussed for a possible On-Board Diagnostic application. 

Oxygen storage capacity of TW catalysts has been widely studied [3-10] and, recently, has been envisaged to serve as a global test of the catalytic activity for On-Board Diagnostic (OBD) [11,12]. In this paper, we shall attempt to correlate the OSC values with the catalytic activity of fresh and aged PtRh and PdRh commercial catalysts for a possible application to On-Board Diagnostic. 

All automobiles produced recently include many processors and sensors, as well as a variety of networks for sensing, control, and entertainment systems. For example, hundreds of sensor parameters are accessible through the on-board diagnostic port. However, there are no connections between these networks and external communications systems, such as cellular phones. The Automotive Multimedia Interface Collaboration (AMI-C) has been working on ways to connect these networks and provide standardized buses in automobiles so a wide range of consumer electronics can be installed. This would create an automotive intranet that could then be conveniently accessed via the Internet (AMI-C, 2001). Ports on the bus could include any of a number of radios, so wireless devices in the vehicle could become part of the intranet, or short-range high-speed communications could be possible between a vehicle and a residence or service station. 

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