Real-Time MPG: Not Just for Hybrids

Getting good gas mileage in any vehicle requires conscious effort and attention to detail, and having a real-time display of fuel economy can provide a clear picture of your driving efficiency. You don’t have to buy a hybrid to do this—if you have a vehicle that was made after 1996, you’re good to go. Several manufacturers, such as PLX Devices (KIWI) and Linear Logic (Scan Gauge), offer real-time mpg gauges, which will help you achieve your hypermiling goals.

The Scan Gauge II meter displays real-time data on a small screen that you stick to your dashboard. The meter plugs into the on-board diagnostics computer port that’s standard on any vehicle made since 1996, the year that OBD-II specification was made mandatory for all cars sold in the United States. You’ll recognize this as a rectangular connector found somewhere under the dash. The Scan Gauge can be configured to show four parameters, including real-time mpg that updates every 2 seconds. Other useful features monitor engine temperature, oil pressure, and even the temperature of the air entering the engine. But simply watching the real-time mpg is an education in any vehicle, since you can use this data to immediately adjust your driving strategy to the road conditions.

It is eye-opening to see a vehicle’s fuel economy plummet from 30 mpg to 8 mpg on acceleration, and then bump up to more than 100 mpg when you take your foot off the gas going downhill. My Ford Escape hybrid did not come with the fancy computer console, so I installed this gauge to monitor real-time mpg and battery state of charge as a percentage. By pressing a few buttons when I return home, I also can review my mpg per trip, day or tank. The simpler KIWI shows only fuel economy info (see Access).

Courtesy Guy Marsden