Equipment Type

Gas-Fired Kenworth: A Truck for the Future?

Each of the KWs has an 8.9-liter Cummins Westport ISL-G engine, an Allison 4500RDS 6-speed automatic transmission, and a McNeilus Bridgemaster mixer body.

February 27, 2012

Look past this mixer truck’s snappy red-and-white paint scheme and check out that huge fuel tank. There are two of them, and they hold natural gas, which has picked up major political backing and is becoming a strong force in motor fuel in the United States.

“This thing is huge,” declared Tom Harris, sales manager at McNeilus, in talking about a trend toward natural gas. The company is actively promoting gas in its “Ngen” program, and he’s been selling many mixers and trash-collection trucks set up to burn it. Compressed natural gas (CNG) is what most use and is what this truck is equipped to handle, and Harris said he believes it’s the fuel of the future.

Kenworth W900S Specifications

Truck: Kenworth W900S, vocational spec w/ 11-5/8 x 3/8-inch frame rails, conventional-cab, BBC 120 inches

Engine: Cummins ISL-G, 8.9 liters (544 cubic inches), spark-ignited natural gas fuel, 320 hp @ 2,100 rpm; 1,000 lb.-ft. @ 1,200 rpm

Transmission: Allison 4500RDS (rugged duty series) torque-converter automatic, powershift 6-speed double overdrive

Front axle: 20,000-lb. Dana D2000 w/ dual Sheppard hydraulic power, on 20,000-lb. taperleafs

Rear axles: 44,000-lb. Meritor MT-44-14X5 on 46,000-lb. Chalmers 854-46-L-HS walking beam

Wheelbase: 248 inches

Brakes: S-cam w/ Bendix ABS

Tires & wheels: Front, 425/65R22.5 Bridgestone M844F on Alcoa aluminum discs; rear, 11R22.5 Bridgestone M711 on Accuride steel discs

Fuel tanks: Two Type 4 CNG, 60 diesel-gallon equivalent

Body: 11-yard McNeilus Bridgemaster w/ 15,000-lb.-capacity swing-down booster axle

“It’s an exciting new thing,” said Tim Ozinga, communications manager for Chicago-based Ozinga Ready Mix Concrete, which bought this gas-fired truck and 12 others like it late last year. “We like to stay on the cutting edge of the industry, and whenever we find something feasible, we like to try it out.”

The company has 27 plants in the Chicago metro area and a fleet of about 400 trucks, most of them mixers. Most are fueled by diesel, but natural gas has become quite a bit cheaper than diesel, Ozinga said, and that’s one reason for this order for CNG trucks. These are the company’s first new trucks in six years, indicating a revival in construction that is as welcome as it was long in coming.

Each of the KWs has an 8.9-liter Cummins Westport ISL-G engine, an Allison 4500RDS 6-speed automatic transmission, and a McNeilus Bridgemaster mixer body. I caught this one at the McNeilus plant in Dodge Center, Minn., a few hours before it was to depart for Illinois. With Harris riding shotgun, I drove it over nearby city streets and a state highway, enjoying its ease of operation. It was a short trip, but enough to make some observations.

First, the spark-ignition gas engine is smooth and quiet, more so than the straight diesel version of the ISL with its traditional compression ignition. And the Allison automatic removes most of the work of operating a truck like this; just punch D on the selector and drive. Or hit R for reverse, which I did to check the KW’s ability to turn—pretty good—and the view through the many windows of its cab. Among them were the curved corner windows that helped provide a 360-degree look at the outside world.

The cab had enough leg and belly room and headroom. Its width was more than adequate for a construction truck and narrow enough to put the right-side window close to the driver’s eyes, which makes it seem bigger than it already is. The cab’s skin and most of its structure are aluminum, which saves weight and resists corrosion. Stout design and hefty door seals require the driver to crack open his window to close his door, which can be a point of pride—wow, this cab’s air tight!—or annoyance—can’t they fix the door so I can just close it? Anyway, the cab feels as solid as a vault, and that’s a good thing.

The almost expansive view over the steeply sloped hood make for safety on the road and at a job site—the better to see you with, buddy. The hood is similar to that on Kenworth’s T800 series, but this truck is a W900S with a set-forward steer axle. T-series trucks, whether medium- or heavy-duty, all have setback steer axles. By the way, both letters in those designations come from the Kenworth name, and K is used for cab-over-engine models. End of lesson on KW’s nomenclature.

The forward-set axle stretches the wheelbase to comply with bridge-formula laws in states such as Illinois. The longer the distance between axles, the more a truck can carry without stressing bridge spans and pavement. This one, with its 248-inch wheelbase and swing-down booster axle, can legally gross 68,000 pounds that usually includes 8.5 cubic yards of concrete in the City of Chicago, Ozinga said. The barrel has enough room for 11 yards.

The Allison torque-converter automatic is a mandatory option. It compensates for the engine’s modest output of 1,000 lb.-ft. and 320 horsepower by multiplying torque at start-up and continuously sending power to the rear wheels at all road speeds. But the engine is strong enough by 200 lb.-ft. to require the 4500 series transmission, which KW prices at $10,000 more than a 3000 series that’s used with midrange engines. Derating the engine would save transmission money upfront, but would it then have enough oomph to carry the load, and would the tranny be beefy enough to live in this service? Maybe not.

Partly because of the easy-to-drive Allison automatics, Ozinga drivers assigned to the new KWs like them, Tim Ozinga said. And they’ve caught on quickly to the gas aspect. “The first driver that got one was a little nervous” about the fuel, he related. “But we did give them training on fueling, and they were impressed with how easy and safe it is. There are no leaks or fumes” because the gas nozzle securely latches onto the truck tanks’ filler necks.

Fueling is now done at a public station in central Chicago, but the company wants to install its own station. That would be expensive, but it would become feasible if this 13-unit trial proves successful and Ozinga buys more gas-powered trucks.

Wags will look at the gas-fired trucks’ huge saddle tanks, which alone cost about $30,000, and scornfully point out that diesel fuel still has more energy and is much more practical than natural gas will ever be. Visionaries will look at the expanding supply of gas in America and its falling prices, not to mention support for gas because of the energy independence it will bring and the jobs its production will create, and some will order more trucks like this. And that will free up fuel for diesel diehards, so we’ll all win.

 
 

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