I used to drive from San Jose, California, to Portland, Oregon and back to visit family on long weekends.
It’s a 650-mile commitment, on par with the maximum distances that an efficient Class 8 truck driver can legally complete in an 11-hour driving period averaging 60 mph. The obligations to family meant I did this trip in all seasons, and in all weather — even negotiating 4,000-feet altitude mountain passes during heavy snow when the semi-trucks were having trouble negotiating the roads.
I’m sure nearly everyone has similar stories. The point is I had a lot of time to think on the road. Invariably, fuel management was always on my mind — where I needed to stop to minimize downtime to keep my average speed up.
I always was wondering just what the “E” in the fuel gauge really meant. How far could I stretch out the refueling and just how efficient could I drive the vehicle. Today, it’s called hypermiling. When I was doing it, it was just ignorance. The owner’s manuals are pretty thin about just how much is actually left in the tank when the fuel gauge points at E. I was running late for a family wedding on one trip and really stretched out the fuel stops, only to wind up out of gas one exit short of a fuel station in Wilsonville, Oregon. It was a different time (pre-cell phone and pre-social media), and a kind person stopped and gave me a ride to and from the gas station. I got to the wedding on time.
[Related: Peterbilt showcases its new SuperTruck]
Fast forward to 2010 and work on the Department of Energy SuperTruck I program with Peterbilt and Cummins. The project’s entire goal was to maximize fuel economy with technology that was realistically capable of going into production in a few years. Weight management was crucial as adding technology means adding weight, so the engineers had to be creative to offset those gains with reductions in other systems. The goal was to improve freight efficiency by 50% for a targeted 65,000 lbs. gross vehicle weight tractor and trailer system on a representative high mileage route.
A baseline 6 mpg tractor on this route had two 100-gallon fuel tanks, one on each frame rail saddle mounted under the sleeper, giving it a potential range of 1,200 miles between fuel stops. The driver, not so equipped for distance, likely could only get about 600 miles per day.
