MOBILE6 and Compressed Natural Gas Vehicles Janet Kremer U.S. EPA Office of Mobile Sources

Current Models Scope  All highway mobile sources (cars and trucks) b HC, CO and NOx Emissions b Exhaust and non-exhaust

Fuel Types b Gasoline (including RFG) b Diesel b Compressed Natural Gas (MOBILE6)

Emission Standards b LEVs, ULEVs & ZEVs b Assumes these vehicles are operated the same as other vehicles b No allowance for separate commercial fleet fraction

Compressed Natural Gas Vehicles in MOBILE6 b Certified Conversion and OEM Vehicles b Single Fuel Vehicles b Light Duty and Heavy Duty b User Input: Percent CNGVs by Model Year

DATA b Lack of In-use data b GRI study b 12 vehicles; 6 CNG, 6 Gasoline b FTP Driving Cycle

Methodology for Light-duty Vehicles b Assumes CNG vehicles operate and accumulate mileage similar to their gasoline counterparts b CNG = ULEV b CNG benefit is equal to the percent reduction in emissions b Applies to all light-duty vehicles

Light-duty Gasoline ULEV vs. Light-duty CNG

Methodology for Heavy-duty Vehicles b Heavy-duty CNG vehicles operate and accumulate mileage similar to heavy- duty diesel and gasoline b Heavy-duty CNG emissions = federal 2004 heavy-duty diesel standards b CNG benefit = difference in standards (for Nox only)

CNG in MOBILE6 b Assumptions and corrections associated with ULEV will apply to CNG b No fuel corrections apply to CNG b No non-exhaust emissions associated with CNG vehicles