Heavy Duty Trucking

AUG 2014

The Fleet Business Authority

Issue link: https://heavydutytrucking.epubxp.com/i/364502

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Page 39 of 109

38 HDT • AUGUST 2014 www.truckinginfo.com Customers' actual operations will determine if that differ- ence converts to better tank mileage, but it does make for rapid acceleration. Power, weight and other factors being equal, a TC10-equipped truck will outdrag one with an auto- mated manual, and will leave a rig with a manual transmission way behind. In a fair comparison, a driver can definitely feel a TC10's smoothness and acceleration advantage. Re- cently, as a guest of Navistar at its Melrose Park, Ill., engine facility, I drove three International ProStars. Two had well- behaved Eaton products (one was a 16-speed UltraShift and the other a new Advantage automated 10-speed). I drove these, and another tractor with a TC10, on city streets and a short stretch of Chicagoland expressway. The gross combination weights of the three rigs were similar, in the mid to high 70,000-pound range. The Eaton automateds changed gears smoothly, but the Allison was more than just "a little better." If I were a driver assigned to a tractor with a current Eaton, I'd be perfectly happy, but I might like the Allison more. I can't say that the Allison is similarly smoother than a Detroit DT12 or a Volvo I-Shift or its Mack sibling, the mDrive, because I have no back-to-back comparison drives from which to make a judgment. But I suspect so. On the other hand, a guy who likes going through the gears and therefore doesn't like a self-shifting transmis- sion might like the Allison even less. Its gear changes are muted and sometimes imperceptible, especially in the test drive The TC10's torque converter con- nects it to the engine, and its front and rear gearboxes use wet clutches for continuous power flow. The test tractors both had strongly rated Navistar MaxxForce 13s making up to 1,750 pounds-feet and 475 horsepower. PHOTO: ALLISON Sensing Allison FuelSense Features A llison Transmission doesn't seem to tinker much with its medium-duty automatics, because it doesn't have to. They're smooth-operating, long-last- ing and virtually eliminate driveline damage from rough off-road service or careless driving. Electronic controls — the brains of modern Allisons — are now in their fifth generation and have allowed engineers to add more value with a package of features called FuelSense. They include programming to keep engine speed at its most efficient level; acceleration management; Dynamic Shift Sensing to determine when low-engine-speed shifts can be made; and Neutral at Stop to save fuel and reduce emissions when the vehicle is stationary. At an introduction in March at the National Truck Equipment Association's Work Truck Show in India- napolis, Allison executives said FuelSense can reduce fuel use as much as 5–15% in city trucks (and 20% in transit buses). FuelSense involves new programming as well as valve changes and a new selector. Features are divided into three levels — Basic, Plus and Max — and can be retrofitted to existing Allison automatics. A demonstration vehicle was on hand at a recent ride-and-drive event. It was an M2-106 from Freightliner, which claims to be the first to adopt FuelSense up- grades in its Allison automatics, starting this summer. The event's format, a 2-mile-or-so drive on city streets around the convention center, isn't enough to demonstrate much to a driver, so Allison reps pointed them out (for instance, the transmission upshifted whenever it could to avoid thirsty high revs), and the loop was enough for me to notice a pair of features: • Acceleration manage- ment. If you spotted this in the above list, you prob- ably guessed that it limits performance when the driver has his foot hard on the pedal. Yes, that means more leisurely take-offs, which some drivers might think of as "doggy." It didn't bother me because long ago I ad- opted a light-pedal approach to preserve equipment and save fuel. • Neutral at Stop. This saves some fuel because the engine doesn't have to work to pump fluid in the torque converter. It also reduces the need to stand on the brake pedal to keep the truck from rolling forward. The FuelSense transmission went into neutral as soon as the truck came to a com- plete stop, and I could feel the pedal rise a bit when it happened. Then, as soon as I released the brake pedal, it returned to drive. Punching N, then D, would do the same thing, but it is far more convenient. This Freightliner M2-106 crew-cab was Allison's demo truck at the Work Truck Show. Some of FuelSense's features are not obvious to a driver, but "acceleration management" and Neutral at Stop are.

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