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August 13, 2014

Heavy Duty Trucks: Power vs. Fuel Economy

Heavy-duty trucks complete the work tasks of essential every day life, from moving a household to building one. Their payload capacity is often categorized as half-ton, three-quarter-ton and one-ton sizes. These descriptions described an older model truck’s payload capacity, the amount of weight a truck could carry when fully loaded. Many of today’s trucks still use these terms, but their payload capacities exceed these common namesakes. When it comes to the payload capacities of a truck, torque is the determining factor in pulling heavy loads. Diesel engines produce the greatest amount of torque and best fuel economy and have become the leading factor in modern day trucks. Lighter weight trucks and better-designed engines have slightly increased fuel economy in today’s trucks.

Torque vs. Horsepower

Torque is the twisting force the engine creates to turn the drive shaft. The transmission then transfers torque to the wheels. Torque gets the truck moving easily from a stop and is essential for hauling heavy loads, like a boat, safely up hill. Horsepower is a measurement of work. It is the amount of energy needed to move an object 100 feet per minute. Horsepower comes into play when a truck pulling a heavy load, like a loaded trailer, needs to pass a slower moving vehicle. The greater the engine’s horsepower the easier a heavily loaded truck will pass a slower vehicle. Having lots of horsepower helps to increase a trucks speed at higher rotations per minute, but when it comes to low-end rpm, torque gives a truck the power to pull heavy loads.

Diesel vs. Gasoline

Diesel engines use compressed air to ignite fuel while gasoline engines use spark plugs. By using compressed air, pistons in a diesel engine travel further, this distance is called stroke. The higher the stroke capacity the more torque the engine creates and the more power over all. A gasoline engines quicker stroke time allows for greater power at faster speeds. Diesel fuel is energy-dense and is about 30 percent more fuel efficient than gasoline engine. Though the base price of gasoline is sometimes cheaper, the gasoline engine is no substitute to the power and fuel efficiency the diesel engine gives for hauling and towing capacity.

Power vs. Fuel Economy

By using diesel engines, trucks greatly increase their torque capacity and can pull heavy loads more easily than gasoline engines. Engines vary in sizes, allowing for greater variables in torque, horsepower and fuel efficiency. To put the same size diesel engine against the same size gasoline engine, the diesel engine will come out ahead, with a stronger towing capability and greater fuel efficiency for longer trips. Heavy-duty truck builders have turned to using lighter materials and currently have designed more efficient engines to increase mpg. To get the power needed for moving, hauling and towing life’s every day needs, fuel economy still remains a challenge for heavy-duty trucks.

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