With diesel prices exceeding $4 a gal. and rising, every gallon saved is money in the bank for truck operators. Truckload carrier, C.R. England, based in Salt Lake City, has compiled a number of fuel economy tips to help drivers and owner-operators manage their miles per gallon:
• Shift Optimization: Shifting should be done as soon as engine speed is high enough to move to the next gear since today's modern engines run better at lower rpm. Constant operation below 1,300 rpm significantly improves fuel economy, C.R. England says.
• Smooth Acceleration and Braking: Drivers should anticipate changes in traffic and road conditions, avoid abrupt stops or rapid changes in vehicle speed, and minimize use of service brakes by planning ahead. Braking not only costs fuel economy because you're losing momentum, but also because you're activating an accessory that draws power — the air compressor, C.R. England notes.
• Exhaust Regeneration: Over-the-road regeneration of diesel particulate filters (DPFs) uses approximately 1 gal. of fuel, while parked regeneration uses approximately 3 gal. of fuel. If the dash light indicates that regeneration is needed while the truck is idling, C.R. England suggests that drivers should try to change duty status if possible so they're on the road when regeneration occurs. The carrier also points out that bio-diesel fuels will increase the number of regenerations required, generate less power and offer lower mpg.
• Driver Stops: Each stop costs approximately one-third of a gal. to return to speed.
Drivers should consolidate stops for food, fuel, showers, maintenance, pre-trips, and personal needs to reduce fuel expense, the carrier suggests.
• Top Gear Cruising: One gear down decreases mpg by approximately 16% due to gear mesh effect. A 20% difference in time spent in top gear could result in as much as a 4% difference in fuel economy.
• Out-of-Route Miles: Drivers should stay on route whenever possible. Each out-of-route mile costs 73 cents in fuel alone at $4 per gal., C.R. England estimates.
• Excessive Idling: Engines use up to 1 full gal. of fuel per hour while idling. If a truck idles 70% of the time, a truck’s overall fuel economy is reduced by almost one-fifth, or approximately 1 full mpg. The carrier points out that modern engines do not require warm up periods or long cool down periods. A 3-minute idle after stopping is sufficient to cool down the engine prior to shut off. Drivers should shut off the truck when not in the cab. If idling is necessary for air conditioning, don’t exceed 900 rpm.
• Tire Tread: Below 50 mph, tires make the biggest difference in driving mpg, the carrier states. Half tread (worn) tires are approximately 6% better on mpg than new tires, the fleet points out. Ribbed tires are 2 to 4% better on fuel economy than lugged tires. Fuel-efficient tire brands can improve fuel efficiency by as much as 0.5 mpg.
• Tire Inflation: Every 10 psi that a truck's tires are under-inflated reduces fuel economy by 1%. Tire condition and inflation is just as important on trailer tires as it is on tractor tires, the fleet says.
• Transmission/Gearing: An engine geared to run 1,450 rpm at 65 mph gets approximately 4% better mpg than one geared to run 1,600 rpm at 65 mph. The optimal transmission gearing, C.R. England suggests, is 9-speed.
• Preventative Maintenance: Ensure all regularly scheduled maintenance services are completed. Poor fuel economy is often equipment related.