The Need for Inspection and Maintenance for Current and Future Motor Vehicles 790782

The majority of automobiles on the road today exceed the emission standards to which they were designed. This failure to achieve the design emission levels is primarily attributed to improper maintenance, tampering with emission controls, and misfueling catalyst cars with leaded gasoline. A method of reducing improper maintenance, tampering, and misfueling is periodic emission inspection and maintenance (I/M) programs.
I/M's ability to deal with in-use emission problems is discussed and contrasted to the other mobile source emission control strategies. The results of EPA's evaluation of the Portland, Oregon, I/M program are presented. This study shows I/M to be extremely effective in reducing emission levels.
A question remains, however, as to whether I/M will be a necessary emission control strategy for the generation of electronically controlled, 3-way catalyst vehicles that will be introduced nationwide in 1981. Recent data on California models and several 1981 prototype vehicles utilizing these control systems show that failures of these new systems, or failure to replace the vehicle's oxygen sensor, can result in extremely high emission levels. The potential for the high emission levels to occur in-use is discussed, and preliminary data on the various short tests' ability to detect high emitting vehicles is presented.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 16% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:

Model Predictive Control: A Unified Approach for Urea-Based SCR Systems


View Details


Airless In-Line Adsorber System for Reducing Cold Start HC Emissions


View Details


Gasoline Sulfur Effect on Emissions from Vehicles Equipped with Lean NOx Catalyst under Mileage Accumulation Tests


View Details