EPA TO "RAISE THE BAR" FOR EMISSION DURABILITY PROCEDURES
On April 2, the US Environmental Protection Agency issued a Notice of Proposed Rulemaking (NPRM) to revise Emission Durability Procedures for New Light-Duty Vehicles, Light-Duty Trucks and Heavy-Duty Vehicles.
This proposed rulemaking contains procedures to be used by manufacturers of light-duty vehicles, light-duty trucks, and some heavy-duty vehicles to demonstrate, for purposes of emission certification, that new motor vehicles will comply with EPA emission standards throughout their useful lives. This action proposes procedures to be used by manufacturers to demonstrate the expected rate of deterioration of the emission levels of their vehicles.
An Overview of the current Certification Process for the "Compliance Assurance Program" (CAP) is as follows:
- Before a manufacturer may introduce a new motor vehicle into commerce, the manufacturer must obtain an EPA certificate of conformity indicating compliance with all applicable emission standards over the vehicle's useful life period. The useful life for cars and light trucks is currently 100,000 miles or 10 years, whichever occurs first; for heavy light trucks, medium duty passenger vehicles (MDPV) and complete heavy duty vehicles the useful life period is 120,000 miles or 11 years, whichever occurs first.
- To receive a certificate, the manufacturer submits an application to EPA containing various information specified in the regulations, including emissions test data. EPA reviews the submitted information as well as any other relevant information, and issues a Certificate upon a determination that the manufacturer has demonstrated that its new motor vehicle will meet the requirements of the Clean Air Act (Act) and the regulations. A certificate of conformity is effective for only one model year, therefore, new vehicle certification must occur annually.
SO WHAT EXACTLY IS EPA PROPOSING?
This proposal includes two well-defined test methods for determining the exhaust emissions durability of vehicles from which manufacturers may choose and it also includes well-defined criteria allowing EPA to approve customization of, or alternatives to, these test methods. These are shown below as alternatives A, B & C.
A. Standard Whole Vehicle Exhaust Durability Procedure.
- EPA is proposing a standard road cycle (SRC), which is targeted to effectively cover a significant majority of the distribution of exhaust emission deterioration rates that occur on candidate in-use vehicles. The SRC is fuel-neutral. It applies to all vehicles, regardless of fuel used. The SRC consists of seven laps of 3.7 miles each. The average speed on the SRC is 46.3 mph, the maximum cruise speed is 75 mph, and the acceleration rates range from light to hard accelerations. Most accelerations are moderate and there are no wide-open-throttle accelerations. The SRC contains 24 fuel-cut decelerations. The deceleration rates range from coast-down (no brake force applied) to moderate.
- EPA is proposing a standard whole vehicle durability procedure which consists of running a vehicle (the durability data vehicle (DDV)) on the SRC for the full useful life mileage of the vehicle. We are also proposing that manufacturers may terminate mileage accumulation at 75% of full useful life and project deterioration factors (DFs) based upon the upper 80% statistical confidence limit. The weight of the vehicle during SRC mileage accumulation is proposed to be the loaded vehicle weight (curb plus 300 pounds) for light-duty vehicles and adjusted loaded vehicle weight ((curb + gross vehicle weight)/2) for all other vehicles covered by this rule. The fuel used on the SRC is proposed to be representative of commercially available gasoline (with a provision that extra poisoning may be added, such as phosphorus, sulfur or lead).
B. Standard Bench Aging Exhaust Durability Procedure.
- Bench aging is a different way to achieve the same emission deterioration as whole-vehicle aging using a road cycle. EPA is proposing a standard bench aging procedure that uses the BAT equation and the standard bench cycle (SBC) to reproduce emission deterioration from a road cycle. EPA's proposed standard bench procedure specifies that the SRC be used to generate the catalyst temperature histogram needed to determine bench aging time. Because the proposed standard bench aging procedure relies on increasing catalyst thermal aging to account for all sources of emission deterioration, this procedure is not applicable to diesel fuelled vehicles or vehicles which do not use a catalyst as the principal after-treatment emission control device. The standard bench aging durability procedure has been designed to reproduce the exhaust emission deterioration that occurs on the standard whole vehicle durability procedure.
C. Customization of the Standard Procedures.
- As a third alternative, EPA is proposing the use of a customized procedural method. To obtain approval for a customized/alternative road cycle the manufacturer would demonstrate that the objective of the durability program will be achieved for the breadth of the vehicles which are covered by the cycle. Approval of a customized/alternative road cycle requires a thorough analysis of whether the cycle will achieve the durability program objective using in-use emissions data, including a demonstration of the relative stringency of the SRC and the manufacturer's program.
- To make the initial demonstration necessary for the Agency to approve a customized/alternative cycle, EPA is proposing that the manufacturer supply high mileage in-use emission data on applicable candidate in-use vehicles. The vehicles would be randomly procured from actual customer use, generally with an age of 4 to 5 years and with a minimum of approximately 50,000 miles. They would cover the breadth of the vehicles that the manufacturer intends to certify using the customized/alternative cycle. Vehicles would be procured and FTP tested as received under the provisions of the IUVP program (ref: 40 CFR 86.1845-04). Manufacturers could use previously generated in-use data from the CAP 2000 high mileage IUVP program or the fourth-year-of-service RDP "reality check" in-use program as well as other sources of in-use emissions data for this purpose. EPA will also consider additional emissions data or analyses that the manufacturer may choose to provide, including data from vehicles which have been screened for proper maintenance and use.
- The amount of in-use emission data required for this analysis is based on whether the customized/alternative cycle is more or less severe than the SRC. In most cases, EPA will accept a minimum of 20 candidate in-use vehicles. There is less risk of underestimating actual in-use emission levels when the customized/alternative cycle is more severe than the SRC. However, if the customized/alternative cycle is significantly more severe than the SRC, EPA may accept less data. Conversely, if the customized/alternative cycle is significantly less severe than the SRC, EPA may require more data up to a maximum of 30 vehicles.
Written comments on this NPRM must be submitted on or before May 17, 2004. Comments may be submitted by mail to:
Air Docket, Environmental Protection Agency
Attention Docket ID No. OAR-2002-0079.
Mailcode: 6102T
1200 Pennsylvania Ave., NW
Washington, DC 20460, USA