Finding More Miles Per Gallon

Fuel economy has long been a major concern for trucking fleets, as it’s one of the largest and fastest growing variable operating costs. Getting more miles from each tank of fuel has taken on even greater significance with the higher, record-breaking fuel prices.
There are a number of simple and immediate steps you can take to save money at the pump. Here are some:
Practice good vehicle maintenance. Along with eliminating avoidable problems that adversely impact a vehicle’s reliability and uptime, the better maintained a vehicle is, the better it will operate. That translates into more efficiency and improved fuel mileage.
For this to happen, drivers must be diligent in performing their daily truck pre-trip inspections and reporting any defects and problems they find. Just as important is having a system in place to fix these reported deficiencies. Making a repair before a vehicle “hits the road” is considerably less time consuming, aggravating and costly than having an on-the-road breakdown and service.
Keep trucks and trailers in alignment. Total vehicle alignment — having the front end, other axles and steering and suspension-related components operating in their proper positioning — helps get more miles per gallon. Misalignment can cause tire-to-road drag and scrub, and side forces, which cause irregular wear and diminished tire life, difficulty in driving and handling and reduced fuel economy. Depending on the misalignment conditions, a vehicle may not exhibit any poor driving characteristics.
Alignment should be checked on a regular basis. A driver can do this as part of his pre-trip walkaround safety inspection by looking for wheel problems and tire injuries. By rubbing a bare hand along the tread and sidewalls, a driver can feel for problems like flat spots, cuts, shoulder wear, sidewall damage and so forth, all of which can result in tire failure.
Maintain tires. The single most critical factor for getting the most out of tires is to maintain proper inflation pressure for a given tire size and load. Because an improperly inflated tire doesn’t roll as smoothly or as easily as it was designed to, rolling resistance and wear is increased and fuel economy is adversely impacted.
Also influenced are handling, traction, braking and load-carrying capability.
Tire pressure should be checked regularly, at least once a week, and always with a properly calibrated tire gauge. Inflation pressure cannot be accurately estimated by kicking or thumping the tire. Trying to determine if tires need air by thumping them is as effective as trying to determine if the vehicle’s engine needs oil by thumping on the hood.
Always check tire pressure when a tire is “cold” — before a vehicle has been driven, or driven less than one mile. When driven on, tires warm up and experience an increase in air pressure, resulting in an inaccurate reading.
Be aware that even well-maintained tires lose air pressure, on average about one or two pounds per month. This is a natural occurrence as air permeates through rubber.
Value caps should be installed on all valve stems and be kept tight. Metal value caps are best, as they contain a rubber gasket to provide an air-tight seal. Most plastic caps do not.
Match tires in dual-wheel assemblies. Along with using the same size tire, each inflated to the same air pressure, tires in dual-wheel assemblies need to have similar tread patterns and tread designs. The tires also need to be matched within a tolerance of not more than one-quarter of an inch in diameter and three-quarters of an inch in circumference.
Inflation mismatches on mated dual tires can cause tire diameters to differ enough that the “larger” tire will drag the “smaller” tire. This results in rapid and irregular wear, especially on the “smaller” tire, and more rolling resistance, which consumes more fuel.
Promote sensible driving practices. Vehicle speed has the single largest impact on fuel economy. Higher speeds also increase engine, vehicle and tire wear, leading to higher maintenance costs and increased downtime.
Fuel-efficient driving techniques can get more miles from each tank of fuel. These include: starting out at the slowest engine speed that will move the load; using the minimum rpm, minimum power and the fewest shifts necessary when accelerating (progressive shifting); running the engine in its peak torque range; using cruise control; accelerating or decelerating well in advance of a stop or a need to speed up; minimizing idling, and planning a trip to be direct and on routes on which you would expect the fewest delays. BI
Equipment news roundup
Volvo Truck of Sweden has designed a new diesel engine to meet the U.S. EPA’s new, more stringent 2007 diesel emissions standards. The engine will be engineered for use in both Volvo Truck North America (VTNA) and Mack Trucks models. Volvo Truck is VTNA’s parent; Mack is an AB Volvo subsidiary. The new engine uses a high-efficiency cooled EGR system for NOx (oxides of nitrogen) control; a special diesel particulate filter with active regeneration and an internal oxidation catalyst for particulate control; closed crankcase ventilation, and an advanced high-pressure fuel injection system.
Peterbilt and Eaton are jointly developing a technology that recycles a truck’s kinetic energy to conserve fuel, assist in acceleration, increase brake life, and reduce engine and transmission wear. Called the Hydraulic Launch Assist, it works by recovering a portion of the energy normally lost as heat by the vehicle’s brakes. This energy, in the form of pressurized hydraulic fluid, is stored in on-board accumulators until the driver next accelerates the vehicle. The stored energy is then used to launch the vehicle during the initial, high-fuel consumption start from stop, followed seamlessly by power from the primary engine. In performance mode, the stored energy is released and blended with engine power at launch.
Kidron is offering Transportation Safety Technologies’ Eagle Eye collision avoidance systems. The systems use sonar technology to sense objects near a vehicle and provide an alarm to the driver. The systems can have from two to seven sensors mounted at the rear and along the sides of trucks or tractors and trailers.
Eaton and International Truck and Engine are participating in a national pilot program to manufacture diesel-electric hybrid trucks, which is part of a three-year U.S. Department of Energy project. The International 4000 Series medium duty trucks will feature an integrated hybrid powertrain — jointly developed by the two companies — that will provide improved fuel economy, generate fewer emissions and allow for quieter operation. The initial powertrain will couple International’s DT 466 six-cylinder diesel engine with Eaton’s hybrid-electric drivetrain, incorporating a transmission, batteries and permanent magnet motor. Power from the engine will be converted directly into electrical energy, which then incorporates the conventional drivetrain to power the truck. The system recovers kinetic energy during braking, charging the batteries while the truck is slowing down, providing additional power for acceleration.