Fuel Efficiency Techniques

I have a clear recollection of the first fuel stop I made after I signed my first lease. I had accepted an Airgas CO2 gig running from Star Mississippi to Eastman Chemical Co in Longview, Texas. I was following another contractor who was going to train me on CO2.  

Until then, I had only ever been a company driver so my financial liability had always been pretty manageable. Someone else up the line had to worry about paying the bills.  

Since I had given all my uniforms, tools and PPE back to my previous employer, I signed for some FRC’s, a nice new hard hat, face shield, hearing protection, and a shiny new brass hammer without one single chip. Since in the CO2 domain, I was as green as the summer grass, I signed for some wrenches and some adapters that were, apparently, of a higher tier of craftsmanship than I had ever actually had to purchase for myself. I also signed on another line for a Freightliner Cascadia with fuel tanks that were very close to empty.

As I watched the dollars and cents steadily climb on the fuel pump, realizing I hadn’t run a single paid mile, I was already in the hole for about fourteen hundred bucks worth of fuel and equipment, and I knew next to nothing about CO2. It was a hell of a reality check.

Don’t get me wrong, those decisions introduced me to a more independent and prosperous life than I had ever known I could have and I don’t regret them. Sometimes, having no one to fall back to is exactly what a person needs to move themself forward, oh, and fuel efficiency techniques. Sometimes having no one up the line to pay the bills makes a person really learn how to stretch a dollar.  

Fuel Cost

According to the ATA, fuel cost is between 20% to 40% of the cost per mile in the trucking industry, so here are some ways to save money on fuel. Although our planet is an unpredictable place and oil and gas is a volatile market, maybe these techniques can help add a little stability to the day-to-day. Some of these probably won’t be popular, but I’m just reporting the news.

Slow Down  

According to an ATA study, a truck traveling 75 mph uses 27% more fuel than one going 65 mph. Fueleconomy.gov says that for every 5 mph you drive over 50 mph, it is equivalent to paying 25 cents more per gallon. I think that is based on passenger car research but they are lighter, more aerodynamic, and have less rolling resistance than tractor trailers. It’s probably not far off. They also found that aggressive driving behaviors like speeding, rapid acceleration, and braking can reduce fuel economy by 10-40%.

Drive Defensively

Drive like you’re in the eye of the storm. Find the sweet spot for your truck. Depending on your gearing, it’s probably somewhere between 1200 and 1400 rpm, wherever plenty of torque is available and lots of horsepower is not required. Set the cruise control. Look into the future, 12-15 seconds up the road, and protect your inertia. Getting all that weight back up to speed is expensive. Protect your inertia, maintain your Zen, and find the sweet spot.

Idle Less  

This one is tough, but it's important to take into account that idling consumes an average of 0.8 gallons per hour. Additionally, when modern emissions trucks undergo regeneration during idle, fuel consumption can increase to 3-4 gallons per hour, and this can occur multiple times throughout the night.

A Webasto or Espar diesel heater can cut that back to .15 gal/hr at full blast which might cook you like a Christmas goose.  

A battery or diesel APU can really cut idle time but the initial investment is high and might only pay off if you keep your truck for a long time. You also sacrifice a little payload for the extra weight and may get pulled into the state scales more often if you load close to gross. I think it would still be worth it just to keep the batteries charged and the sodas from exploding during the winter when you’re out of the truck.

Trip planning can also help cut idle time. When possible, steering clear of major metro areas during drive time or bad weather can help you avoid traffic jams. Trip planning also helps us not miss exits and drive around in circles of unpaid miles trying to find your way back to civilization.

Maintain Your Equipment

Check your tires – Under-inflated or misaligned tires cause excess rolling resistance and hurt fuel economy. Alignment issues will also lead to tires expiring before their time.  

Check your filters – If a truck inhales a fuel-air mixture and exhales spent emissions, then clogged filters are like breathing problems for an engine.

Dirty air filters cause weak combustions and an excess of unburned fuel in the exhaust. In pre-emissions trucks, little dollars signs blowing out of your stacks covered in black soot and for modern emissions trucks, it results in more frequent regenerations, compromising horsepower, and causing your particulate filter to clog up quicker than usual. In the worst-case scenario, dust and dirt get through the air filter completely and your turbo, cylinder sleeves, and piston rings get dusted.

Dirty fuel filters can cause slow or no starts, rough or noisy idling, sluggish performance, and stalls.

Charge Air Cooler – This is the thing in front of you radiator. Basically, it’s a radiator for your turbo. The charge air cooler, or intercooler, is a heat exchanger for the exhaust gases that the turbo is pumping into the cylinders. The cooler the fuel-air mixture, the bigger the bang. A bigger bang for the same amount of fuel equals savings. Check your CAC for cracks and leaks. I replaced one on my Century that had around 600k so this mostly applies to older trucks but better safe than sorry.  

At A Glance

• Slow down. Unnecessary horsepower costs money. Depending on the gearing, most trucks will produce max torque at 1200-1400 rpm and this is probably not at 75 mph. Balance hp and torque for peak efficiency. 
• Idling is expensive. Fuel is burning and the wheels aren't turning. Try to plan your trips to avoid busy drive times and traffic jams. Consider climate control alternatives like a diesel-fired bunk heater or an APU.
• Maintain your equipment. Check the tire pressure. Check your filters, and watch and listen for leaks. Watch for spots of fuel or oil on the ground.