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With the introduction of Euro- III emission regulations for 2-wheelers in Europe, emission control for motorcycles and scooters has become a significant technological challenge. While many vehicles have shifted from 2-stroke to 4-stroke, they are mostly still open loop carbureted or in some cases fuel injected. Euro- III regulation requires emission measurement from key-on and has a high speed phase for vehicles over 150cc engine displacement. The combination of cold start fuel enrichment (with or without secondary air injection) and high exhaust flow rates is particularly challenging for controlling the emissions of THC, CO and NOx simultaneously. If the engine is tuned lean to reduce THC and CO emissions, NOx emissions will increase during high speed operation. On the other hand, if the engines are rich tuned, this increases the cold start and/or high speed acceleration mode THC and CO emissions.

To comply with worldwide global emission standards, Catalyzed Soot Filters (CSF) have been applied in a number of different configurations on passenger vehicles. To meet the regulated Hydrocarbon (HC) and Carbon Monoxide (CO) emissions, Diesel Oxidation Catalysts (DOC) were used in conjunction with a CSF to treat the particulate emissions. To reduce the amount of emission control hardware on a vehicle, OEMs have been looking at simplifying DOC+CSF systems or moving to CSF only catalysts. The progress made in this area over the past few years will be explained. More compact or reduced volume emission control hardware requires that the DOC functionality be integrated on the CSF in order to meet gas phase CO and HC emissions. First generation soot filters were not designed to accept high levels of catalytic coatings and still meet engine back pressure requirements.

With the introduction of Euro III emission regulations for 2-wheelers in Europe, emission control for motorcycles and scooters has become a significant technological challenge. While many vehicles have shifted from 2-stroke to 4-stroke, they are mostly still open loop carbureted or in some cases fuel injected. Euro III regulation requires emission measurement from key-on and has a high speed phase for vehicles over 150cc engine displacement. The combination of cold start fuel enrichment (with or without secondary air injection) and high exhaust flow rates is particularly challenging for controlling the emissions of THC, CO and NOx simultaneously. If the engine is tuned lean to reduce THC and CO emissions, NOx emissions will increase during high speed operation. On the other hand, if the engines are rich tuned, this increases the cold start and/or high speed acceleration mode THC and CO emissions.

Gasoline engine oils contain a variety of additives including phosphorous-based compounds, for maintaining their characteristics. During the life of the vehicle, oil is consumed via piston ring blowby or leakage from valve stem guides. Phosphorous compounds from the consumed oil end up being deposited on the three way conversion catalysts resulting in a degradation of the conversion efficiencies of all three pollutants, hydrocarbons, carbon monoxide and nitrogen oxides. To simulate this deterioration in performance, an accelerated aging cycle has been developed which replicates the effect of the interaction between the phosphorous species and the washcoat components. This paper describes the poison aging protocol and the effect of aging temperature, poison level and duration of aging. In this paper, we will we also discuss some of the catalyst deactivation mechanisms and methods to simulate them using dynamometer-mounted engines.

Gasoline engine oils contain a variety of additives including phosphorous-based compounds, for maintaining their characteristics. During the life of the vehicle, oil is consumed via piston ring blowby or leakage from valve stem guides. Phosphorous compounds from the consumed oil end up being deposited on the three way conversion catalysts resulting in a degradation of the conversion efficiencies of all three pollutants, hydrocarbons, carbon monoxide and nitrogen oxides. To simulate this deterioration in performance, an accelerated aging cycle has been developed which replicates the effect of the interaction between the phosphorous species and the washcoat components. This paper describes the poison aging protocol and the effect of aging temperature, poison level and duration of aging. In this paper, we will we also discuss some of the catalyst deactivation mechanisms and methods to simulate them using dynamometer-mounted engines.

The key to meeting the SULEV (Super Ultra Low Emission Vehicle) standard is a combination of catalyst technology, vehicle calibration and system design. This paper outlines the design of the various components and their contributions to developing a vehicle emission control system that meets the SULEV standard. While it is certainly possible to meet the SULEV standard, it is critical to use appropriate catalyst technology, optimize the engine calibration, and develop a catalyst aging cycle that accurately mimics the on-road deactivation of the emission control system.

On-Board Diagnostics for emissions-related components require the monitoring of the catalytic converter performance. Currently, the dual Exhaust Gas Oxygen (EGO) sensor method is the only proven method for monitoring the catalyst performance for hydrocarbons (HC). The premise for using the dual oxygen sensor method is that a catalyst with good oxygen storage capacity (OSC) will perform better than a catalyst with lower OSC. A statistical relationship has been developed to correlate HC performance with changes in OSC. The current algorithms are susceptible to false illumination of the Malfunction Indication Light (MIL) due to: 1. The accuracy with which the diagnostic algorithm can predict a catalyst malfunction condition, and 2. The precision with which the algorithm can consistently predict a malfunction. A new algorithm has been developed that provides a significant improvement in correlation between the EGO sensor signals and hydrocarbon emissions.