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Check Out an NG-Powered Cascadia

Posted: April 17, 2017 by Jim Park

 

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The natural gas version of the Cascadia 113 is every bit as capable as its diesel sisters.  Freightliner’s Cascadia 113 and the ISX12 G from Cummins Westport aren’t exactly strangers. New to readers’ eyes perhaps, but about 100 of the trucks have been in customer hands for some months now. Some will recall a 350-hp ISX12 G-equipped Cascadia 113 day cab made a cross-country trip from Long Beach, Calif. to Washington, D.C. in April 2012. That was ostensibly to prove the availability of compressed natural gas in a long-haul environment, but it was a good shake-down cruise for the truck as well.

In May, Freightliner began pre-series production of the 113 equipped with the 350-hp version ISX12 G. In mid-August, the truck went into production with the new 400 hp / 1,450 lb-ft rating. Five of that group became customer demo trucks that Freightliner will put into the hands of curious fleets over the next year or so. Freightliner sold them to Penske and leased them back, so they are plated and registered for fleet service. We had a chance to spend the better part of a day in one of those trucks in Napa, Calif. at the end of July.

These trucks feature a new fuel storage system developed in cooperation with Saddle Creek Logistics Services of Lakeland, Fla. and Agility Fuel Systems, Freightliner fuel tank supplier. The compressed natural gas storage array consists of a back-of-cab cabinet holding up to four 25 diesel gallon equivalent CNG tanks, and one saddle mounted 40 or 45 DGE CNG tank. Up to two saddle tanks can be spec’d, as well as three or four tanks in the cabinet, which increases the range of the truck considerably — weight and cost notwithstanding. The four-tank cabinet weighs 2,600 lb, while each 45-DGE saddle tank weighs 1,750 lb.

The cabinet-mounted CNG tanks have been redesigned for a better fit behind the cab, and engineers are developing an aerodynamic fairing and cab-extender package to improve fuel efficiency even further. Early versions of fairing package — very similar to what you see on the Cascadia Evolution — are in tests now with Saddle Creek. They should be on the market by mid-2014.

Powered by Natural Gas

The highest rating for the diesel version of the Cummins ISX12 is 425 hp with a maximum 1650 lb-ft of torque. At 400 hp and 1,450 lb-ft, the natural gas version of the engine is hardly lacking. Interestingly, the torque-multiplying effect of the Allison 4000 HS automatic transmission more or less makes up the difference.

I had the truck for about five hours in Napa, so the first thing I did was head south to Interstate 80 and the hill leading into Vallejo to give the engine a workout. It’s not the Grapevine, but it’s a couple of miles long and close to six percent in a few places. With a gross weight of about 60,000 pounds, I was close to a nearly average load for many regional haulers where the engine will find work.

The engine brake did an admirable job keep our speed in check coming down the hill, and even initiated a downshift to increase the retarding effect when the speed began climbing.

Climbing eastbound out of Vallejo, as the grade changed, I found the engine was looking for the highest gear possible to keep the revs down close to 1200 rpm where the torque is. That held true even on the lesser grades later in the drive. On several occasions, the revs drifted down to the 1,000 mark, which really surprised me. And there was still some pull there.

Though it’s a small displacement engine coupled to a 6-speed automatic — and therefore has a limited number of gear options — it behaves like its bigger cousins leaning toward low-rpm cruise speeds.

New Territory

While the ride and comfort of the Cascadia can hardly be overstated, I’ll say that the 113 BBC model is every bit as quiet, smooth and comfortable as its long-nose brother. It’s supremely quiet in the cab, thanks in large part to the NG engine. They just run quieter than diesels. That said, fleets would be mistaken to simply throw a driver the keys and expect life to go on.

Other than the fueling process, there’s nothing drivers need to do differently but the truck does make some funny noises that they won’t be used to hearing and the throttle response is a bit different from a diesel. The engine tends to surge when stopped at a light after few miles of running. It idles at about 800 rpm rather than 600, and drivers will notice a ‘chuffing’ sound when they take their foot off the throttle pedal. This is all normal, Freightliner assures me, but a bit of orientation time will ease drivers’ concerns before they even start.

I had only two concerns with the customer demo truck that day in Napa; two long clamp bolts on the air intake piping hang down right above the oil dipstick, raising the potential for minor flesh wounds when withdrawing the dipstick, and the steel doors on the back-of-cab CNG tank cabinet rattled. Both of those issues, I would think, could be resolved with a little attention to detail at the engineering stage.

I think drivers and fleets will be pleased with the performance of the NG-powered Cascadia 113. It lacks for nothing compared to the diesel version, and it’s even quieter. With the increased fuel capacity and longer trips that will result from that, it’s a truck I’d be very happy to spend a 14-hour day in.


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