New Standard for Measuring Hybrids and Plug-ins Fuel Economy

The trouble with measuring fuel efficiency of a vehicle that doesn't necessarily use gas is a tough one. Just look at the ridiculous numbers floating around for the Volt (230 mpg) and the Nissan Leaf (an electric vehicle!). I mean, really, what does an MPG rating for an electric vehicle mean to anyone?

You quickly get the idea that some sort of standard needs to be worked out. And not the same one that works for gas-only vehicles.

Plug-ins or Electric Range Extended Vehicles (E-REV), in particular, are tough. If you can drive 40 miles on all electric, then switch over to gas powered, you probably aren't interested in knowing your mpg as we know it. If you drive less than 40 miles a day, you may not need to worry about your 'fuel economy', but you may be very interested to know how much electricity your using. Or, if you do go over the 40 mile range, the traditional mpg rating could be very important, since you want to know how much gas you're using.  Then throw in the whole city vs highway driving.

And just to complicate matters, you want to be able to compare the E-REV to the plug-in to the hybrid to the gas-only vehicle when you go out to buy one (otherwise what's on the sticker the dealer has to put there becomes worthless).

In order to combat the problem, a standard is needed and the SAE International says they have one.

The SAE International has released a new standard to measure the exhaust emissions and fuel economy of hybrids and plug-in hybrid electric vehicles (PHEV) and all their variants. The new standard is J1711 - Recommended Practice for Measuring the Exhaust Emissions and Fuel Economy of Hybrid Electric Vehicles, including Plug-in Hybrid.

It can be applied to any Hybrid Electric Vehicle (HEV). An HEV is defined as a road vehicle that can draw propulsion energy from both of the following sources of stored energy: 1) a consumable fuel and 2) a rechargeable energy storage system (RESS) that is recharged by an electric motor-generator system, an off-vehicle electric energy source, or both.

For more information about the standard, visit http://standards.sae.org/j1711_201006.