PORTLAND, Ore. –Daimler Trucks North America (DTNA) has invested about US$2 billion into the development of its Freightliner Cascadia and Detroit Diesel DD15 engine.

You’d expect a pretty lethal combination would result from an investment of that magnitude.

The first production Cascadia/DD15 combos are making their way to fleets, with officials saying a disproportionate number are being shipped to Canada. Intrigued by the interest this pairing has garnered here at home, I recently travelled to Freightliner country in scenic Portland, Ore. to take one for a drive.

An aerodynamic tractor

With the Cascadia, DTNA has managed to optimize air flow around the truck without straying too far from the recognizable appearance of its Columbia and Century Class -the trucks the Cascadia will eventually replace. Rather than a major facelift, the truck’s designers focused on subtle tweaks, that collectively amounted to aerodynamic improvements to the tune of 20% compared to previous Freightliner models.

All this was achieved without drastically rearranging the familiar face of the Freightliner highway tractors you’ve come to know.

“If it was up to us aerodynamicists, it would look like a bullet train,” joked Matt Markstaller, manager, product validation, who I chatted with in Daimler’s wind tunnel following the drive. Instead, it’s a juggling act between areodynamicists, engineers and stylists.

“The styling people will come over and say ‘We need a reflection line here, we need a crease there,’ and we’ll say ‘We can’t give you that much, but we can give you this much.’ And then the engineers will say ‘But the radiator won’t fit’,” explains Markstaller. “It’s truly a three-way negotiation.”

Some of the aerodynamic features of the Cascadia are evident at first glance. Others would likely go unnoticed if they weren’t pointed out. Some of the more obvious refinements include rounded fenders with flush lighting, a tighter wheel well and a lower bumper with an air dam underneath. The roof cap rises more rapidly than on the Century Class or Columbia and the side extenders are kicked out slightly to route air around the vehicle, away from the trailer gap.

Attention to air flow has even been extended to underneath the hood. Keith Harrington, manager product marketing, new product development with Freightliner and my passenger for the trip explained that air molecules are like a pinball once they’re trapped under the hood.

So under-hood components have been re-shaped to direct air to where it’s needed for cooling and then to send unwanted air out a new vent along the side of the hood.

“Aerodynamics is not a matter of 10% here, 20% there. It’s half a per cent. It’s a 1% refinement -all those subtle things you tend to miss with the eye,” Harrington explained.

Inside the cab

The Cascadia I was provided with for the test drive was an engineering truck -so it was decked out with all the bells and whistles. Disc brakes around the entire tractor, Eaton VORAD, adaptive cruise control, a lane departure warning system and an electronic stability system as well as a trailer stability system were all featured on this truck. It must be the safest truck on the road with all those toys. I quietly wondered if they rigged it up that way just for me?

“It still requires a human to drive it,” Harrington reminded me.

Another safety enhancement was RollTeck -a feature from Sears Seating and IMMI -which includes an airbag mounted to the side of the seat in conjunction with a seat pre-tensioner system. If a rollover occurs, that side air bag deploys to keep the driver’s extremities from falling out the window, while the seat is automatically lowered to protect the driver from a collapsing roof.

The truck was also equipped to accommodate FleetBoard, a new program still under development by DTNA which will display fault codes and alert a driver to any performance issues before a breakdown occurs. Drivers will also be able to use FleetBoard to communicate with home and a truck-oriented GPS program will be integrated into the system.

The Cascadia I was driving had a 13-speed Eaton UltraShift transmission with Freightliner’s proprietary paddle shifter, which is fun to drive and also clears up more room between the seats.

The steering wheel featured an intuitive and functional layout. It wasn’t overly busy, but it placed the most frequently used tools right at my fingertips. Buttons on the steering wheel allowed me to control the engine brake and cruise control. There’s also a handy ‘marker interrupt’ button which flashes your rear lights twice when pressed. I’m all for any function that contributes towards driver courtesy.

The Cascadia is a well-researched truck and everywhere you look you’ll find signs of the attention to detail that went into its design. A discreet button on the passenger side, when pushed, reveals a trash bag receptacle. The screws on the dash are now exposed -a bit of an eyesore? Maybe. But the truck is a work tool after all, and it makes the wiring and gauges more easily accessible for service.

“We’ve gone back, but this is what people asked for -they want serviceability on the truck,” reasoned Harrington.

The radio has been relocated to a new position higher on the dash, where it’s safe from coffee spills. The sleeper cab’s HVAC system can be overridden from the driver’s seat, so a driver doesn’t have to reach behind to adjust the sleeper temperature if it’s out of synch. There’s even a light at the foot of the lower bunk -an explanation was required for that: “Nobody sits there,” admitted Harrington. “But women commented that when the top bunk is lowered, you can’t see well enough to make the bed. It’s those little inputs you get from people.”

Clearly the Cascadia was built to appeal to everyone; drivers of all genders, shapes and sizes. The doors are 20% larger to allow to-day’s ‘bulkier’ drivers to climb in and out of the truck with ease. And the rest of the interior is deceivingly spacious, despite the exterior refinements which give the Cascadia a sleeker appearance than its predecessors.

The cabinets feature molded-in colours so scrapes and scratches won’t be visible. And they’re constructed of a material that doesn’t squeak or rattle when driving down the road.

On the road

Having familiarized myself with the layout of the truck and its various capabilities, it was time to head out on the road. Our route would take us from Freightliner headquarters, down I-5 to I-84, where I’d drive about 45 miles east along the Columbia River Gorge. The drive was scenic, despite Oregon’s predictable gray skies and low cloud cover.

The highway was lined by the Cascade Mountain range -appropriate, since the Cascadia derived its name from this same range. (An interesting side note, Freightliner employees were asked to help name this truck. Thousands of suggestions were submitted and a handful recommended ‘Cascadia.’ The winners received an expense-paid trip to the Mid-America Trucking Show for their creativity).

Out on the highway, the lack of wind noise was immediately noticeable. The DD15 itself is inherently quiet, and paired with some design enhancements to the Cascadia the result is a remarkably quiet ride. Harrington explained the windshield was repositioned to improve airflow and the seat bases have been redesigned to resist noisy vibrations. The gear shift lever is now fullyinsulated (or it would be, had the truck I was driving been equipped with a manual transmission).

“We quieted down everything and all of a sudden we found out we had noise coming from the shift lever up from the transmission, so we had to isolate it,” explained Harrington. “We didn’t know we had all these different noises. As you reduce noise, you start chasing sources of noise you never knew you had.”

I thought I heard a rattle as we cruised down I-84, but alas it was only the lane departure warning system advising me that I had strayed a bit too close
to the shoulder of the road.

Also contributing to the smooth ride was Freightliner’s rack-andpinion steering – an automotive touch that Harrington said is increasing in popularity.

Rack-and-pinion steering is much more precise than traditional truck steering systems and it eliminates bump steer – the input you get from the road when you pass over a bump.

It gives you a more accurate feel for the road and also eliminates the tendency to overcorrect, a mistake I’m sometimes guilty of while getting the feel for a new truck.

A diesel particulate filter (DPF) regeneration occurred during my drive. I was alerted to it by a light on the dash – otherwise, I’d never have noticed. Speaking of the DPF, the active regeneration toggle switch is concealed by a plastic cover, so drivers are less likely to muck around with it.

Despite the constant threat, it didn’t rain during my 90-some mile run. I was secretly hoping it would, to see how the new rubber lip on the edges of the windshield would work. It’s designed to direct water away from the side windows and mirrors so as to not obstruct visibility. I’ll have to take DTNA’s word on that one.

The DD15

Most Canadians would probably prefer a more powerful version of the DD15 I was driving. But even at 505 hp, 1,650 lb.-ft. of torque, the engine handled some fairly steep, long uphill grades with ease. The gross combination weight was about 75,000 lbs, yet we were up to speed in no time thanks to the engine’s impressive and immediate torque response.

The DD15 reaches 90% peak torque in as little as 1.5 seconds and it maintains full torque from 1,100 RPM right though to 1,700 RPM. That long, flat power band makes the DD15 simple to drive and reduces the need to continuously change gears, even on hills.

While the fully-insulated Cascadia itself has been designed to dampen exterior noise, the engine also plays a part. Traditional diesel engines have individual injections which create the sound of one big explosion followed by a knock, producing the diesel engine noise you’re accustomed to hearing.

However, the DD15 has multiple injections per cycle: a preburn; main burn; and follow up.

“You no longer have that main explosion, you have a continuous explosion and that cuts down on the noise,” explained Harrington.

This is made possible by the DD15’s extremely high injection pressure of 32,000 PSI (traditional diesel engines ranged from 3,000 PSI up to about 20,000 PSI).

Another feature exclusive to the DD15 is turbo-compounding. It’s not a new technology – it’s been around since WWII days – but it is new to trucking. Previous

TURBO-COMPOUND: Turbocompounding, available on the DD15, allows for the recapture and use of 50 ‘free’ horsepower that is normally wasted.

engines featured a ‘wastegate’ which released excess turbo pressure unused.

The turbo-compounding process recaptures that previously wasted energy and converts it into 50 ‘bonus’ horsepower. I asked Harrington why it took over 50 years for the technology to find its way into trucking.

“There was no incentive with the price of fuel (in the past),” he said. “Since we’ve had to go through the emissions requirements and focus on maximizing performance, you start looking for any technology – new and from the past – that you can use that will aid performance. Rather than twin turbos, we found the turbocompound was the perfect fit, especially when you have a rear geartrain close to the turbo.”

Turbo-compounding, and other design enhancements, make the DD15 2-5% more fuel-efficient than the Series 60, I’m told.

On the hills, the engine brake was nearly soundless. It’s activated by a toggle switch on the dash and then controlled with a button on the steering wheel.

Fleets will appreciate the seemingly endless options for programming the DD15.

You can set the heated mirrors to automatically come on when the temperature reaches the freezing point. You can program the utility lights on the back of the cab to turn off at a given speed. You can set the turn signal to automatically shut itself off after so many clicks. You can program the headlights to automatically come on when the windshield wipers are activated. And you can even shut off cruise control at a certain ambient temperature to lessen the risk of a jackknife.

“In the old days, you’d have to hardwire all this,” said Harrington. “Now you sit with a laptop and program the parameters.”

DTNA spent US$1.5 billion on developing this engine alone, and its improvements over the Series 60 – a very successful engine in its own right – are clear from the driver’s seat. Canadian drivers especially will love that long, broad torque band – it’s little wonder that a disproportionate number of the Cascadia/DD15 combinations are being shipped north.

The verdict

If I could sum up my drive in one word, it would be ‘comfortable.’ The dash was laid out intuitively and the steering wheel was functional, but not cluttered.

The lack of wind noise combined with the quiet operation of the DD15 provided one of the quietest drives I’ve experienced in anything with more than four wheels.

The unique torque curve of the DD15 handled hills with ease and minimized the need for gear changes.

Add rack-and-pinion steering and the UltraShift transmission to the equation and the truck was both easy and fun to drive. I’d go so far as to say it rivaled the comfort expected from a high-end passenger car.

With record fuel prices showing no signs of abating, the challenge for truck and engine manufacturers will be to provide vehicles that combine productivity and efficiency with the ever-increasing comfort demands of drivers.

The Cascadia/DD15 combination strikes this delicate balance – no wonder it’s already generating so much interest.