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The little engine that could

MOUNT VERNON, Wash. – As the buzz surrounding natural gas as a viable alternative to diesel in the heavy truck industry continues to grow, manufacturers have rapidly expanded their natural gas-fueled offerings in an effort to position...

MOUNT VERNON, Wash. – As the buzz surrounding natural gas as a viable alternative to diesel in the heavy truck industry continues to grow, manufacturers have rapidly expanded their natural gas-fueled offerings in an effort to position themselves as leaders in this emerging market.

There is no arguing the potential cost savings when switching from diesel to natural gas. A recent Conference Board of Canada report entitled Cheap enough? Making the switch from diesel fuel to natural gas, concluded that fuel savings of up to $150,000 per truck over a 10-year period are attainable at the current price spread between diesel and natural gas. Such savings are enough to pay for the cost of the technology two, maybe even three times over a 10-year period, which is a compelling proposition for regional fleets where truck life-cycles are typically longer than in over-the-road applications.

In regional applications, one option worth considering is Kenworth’s T440, available with the Cummins ISL G natural gas engine in either a Class 7 or 8 configuration. I recently spent some time behind the wheel of a Class 8 version of this truck, pulling a loaded trailer on the roads surrounding Paccar’s Technical Center in Mount Vernon, Wash.

I wasn’t able to stray too far from the tech center, ironically because of fuel limitations, which remains one of the two biggest concerns of most fleets considering the switch to natural gas (the other being the cost of the technology). Availability of both CNG and LNG is quickly improving on both sides of the border, however, with new partnerships between opportunistic gas suppliers and heavy vehicle users resulting in a rapid rollout of fueling stations.

The T440 I drove is in many ways an ideal regional truck for lighter loads on reasonably flat roads. The ISL G engine can be spec’d to run off natural gas in either liquefied or compressed form. In Canada, the most high profile fleets to embrace natural gas have gravitated towards liquefied natural gas with Westport’s 15-litre LNG engine. This is understandable as LNG offers greater range for longer routes such as Montreal-Toronto, the lane on which Robert Transport has deployed most of its natural gas vehicles.

In more regional applications, however, OEMs speak favourably of CNG, which lacks the range of LNG but is simpler to handle. Drivers can watch a five-minute video to learn everything they need to know about fueling their truck with CNG while certified handlers are required to fuel vehicles with LNG. Liquefied natural gas also comes with more limitations in terms of where trucks can be parked or operated. Less driver training is required with CNG as well.

“With CNG, a driver can just get in the truck and go within 15 minutes,” said Alan Fennimore, vocational marketing manager with Kenworth. “That type of technology has been around for pushing 30 years now.”

Fleets considering adding natural gas trucks to their operations will want to research the fueling infrastructure available in their vicinity. In many cases, Fennimore said, natural gas stations offer both types of fuel since LNG can be easily converted to CNG on-site.

The T440 I drove was fitted with two 40.5 diesel gallon equivalent (DGE) tanks, good for about 350 miles (560 kilometres). The ISL G is an 8.9-litre, spark-ignited engine available with up to 320 hp and 1,000 lb-ft. of torque. At first glance it seems underpowered for most Class 8 applications but don’t underestimate the capability of this little engine. On my drive, it performed beyond expectations, thanks largely to the deceptive torque delivered in combination with the standard Allison 3000HS six-speed automatic transmission.

When I told Fennimore I was pleasantly surprised by the abundance of torque, he credited the Allison transmissions torque converter and its torque multiplication capabilities.

“In first and second gear, you’ve got that torque converter that allows you to basically slip and that slipping allows you to get an additional gear range so it doesn’t feel like 1,000 lb.-ft. of torque, it feels like 1,350 lb.-ft.,” Fennimore explained. “It was a conscious decision by Cummins to only offer the Allison transmission and it was a good decision. For a manual transmission to pull 80,000 lbs with 1,000 lb.-ft. of torque is very tough. Having that gear multiplication in first and second gear gives you that gradability you need to get a heavy load off the ground.”

The other attribute of the ISL G that’s immediately noticeable is its quiet operation, even in a day cab pulling a heavy load. You become more attuned to other sounds, like the operation of the air compressor, which traditionally were drowned out by the rumbling of a diesel engine.

Real-world users of the ISL G, including Swift Transport CEO Jerry Moyes, have said the engine is undersized for heavy loads and it certainly could be, even though it greatly outperforms its single-digit displacement. Cummins will soon have an answer to this with the release of its ISX12 G engine, slated for launch in 2013. Still, the T440 with ISL G is an excellent truck for lighter loads running short routes, especially in the city where its maneuverability and visibility will be fully appreciated.  

The fuel capacity on the T440 is limited by its short 193-inch wheelbase. Fennimore said fleets can get more range by spec’ing larger tanks and in some cases have mounted a third CNG tank on the back of the cab.

If range is a major concern, it may be worth stepping up into a T660 model which allows for 100 DGE of fuel capacity on the frame rails and the option of a third tank on the back of the cab bringing total capacity to upwards of 140 DGEs.

But with range comes cost. The fuel storage system accounts for at least half the premium you can expect to pay for a natural gas-powered vehicle. The ISL G costs about $25,000 more than an ISL base engine and two CNG tanks will set you back another $25,000, bringing the total upcharge to about $50,000. Cheaper, steel tanks are available but Fennimore said most customers are investing in the more durable Type 4 composite tanks, which are lighter weight and feature a plastic core wrapped within a carbon fiber composite material.

Kenworth likes the T440 as a natural gas vehicle because “it was just the right size,” Fennimore explained. The company considered making its T800 short hood model its natural gas guinea pig but in the end, Fennimore said, “we decided to put it in a lower content vehicle to keep costs down.”

The larger cooling module of the T800 was seen as overkill and so it was decided the T440 offered all the requirements needed of a natural gas-powered regional truck at a lower cost. Because natural gas is a clean burning fuel, the truck doesn’t require a diesel particulate filter (DPF) or selective catalytic reduction (SCR) emissions system. Just a back of cab-mounted three-way catalyst is all that’s required for emissions compliance.

Drivers won’t have anything to complain about when operating this truck as long as it’s placed into the right application and isn’t asked to do too much.

Remember, this is a workhorse medium-duty truck available in a Class 8 configuration but it’s no heavy hauler.

The T440 with ISL G may not be the right truck for pulling heavy loads over the Rockies, but a regional fleet operating within a metro area pulling lightish loads on regular routes of 500 kilometres or less would be a perfect fit, provided the fueling infrastructure is available.

If the Conference Board of Canada report is to be believed, running a T440 with ISL G engine in such an application over a 10-year period could actually deliver a six-figure savings even after the cost of the technology is accounted for. How can you not be intrigued by that?

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