Information about Family Naming Conventions for Vehicles and Engines
On this page:
- Step 1. Find the applicable model year code
- Step 2: Determine your manufacturer code
- Step 3: Find your industry sector
A family is the basic unit that EPA uses to identify a group of vehicles or engines for certification and compliance purposes.
- Engine family;
- Test group;
- Vehicle family;
- Durability group; and
- Evaporative and/or permeation and/or refueling family.
A manufacturer should apply for new certificates and pay the appropriate certification fees for each family name that it intends to produce for sale in the United States.
A family name is a 12 character code that identifies all parts of that particular engine.
The typical naming convention is shown below, although some sectors have a slight variation.
* For dual or variable displacement families, enter the maximum displacement. If the displacement is given in liters, the decimal point count as a digit. In all cases, the displacement will be read in liters if a decimal point is included and it will be read in cubic inches or cubic centimeters if there is no decimal point.
Follow these steps to create your family name:
STEP 1: Find the applicable model year code.
From the table below, find the code for Position 1 of your family name.
STEP 2: Determine your manufacturer code.
This code is the 3-character, alpha-numeric code that EPA assigns to each company. Use this code for Positions 2-4 of your family name.
STEP 3: Find your industry sector.
Click on your industry sector to view specific instructions for determining Positions 5-12 of your family name.
* This also includes heavy-duty highway vehicles at or below 14,000 pounds GVWR that are not tested on a chassis-dynamometer for certification under 40 CFR Part 1037 (i.e., certified to the requirements and standards of §1037.105, per §1037.104(f)) and powertrain testing configurations as described in 1037.231 (encompassing engine, transmission, and axle) when powertrain testing is used for certification of any vehicles within a family.