Feeling the Pulse

This is the second in a series of test drives of the lower-emissions engines.

Veteran and rookie drivers alike have voiced concerns about the new lower-emissions engines to debut this October.

Take, for example, Jim Howard, who I met while test-driving the Volvo D12D with exhaust gas recirculation (EGR) technology. Howard, three weeks into his six-week finishing course with The Mickow Corp., expressed his reservations about the new power units while unloading coils at a dock in western Pennsylvania. “I wonder about performance, especially on grades,” he said. “And I wonder about durability.”

But now that I have driven both the Mack and the Volvo, I am confident drivers will not be disappointed in the new engines’ performance.

I began my test drive in Greensboro, N.C. The Volvo daycab, powered by a 435 horsepower unit with 3.73 rears, roared off the Volvo corporate campus grossing 70,000 pounds ready and willing. I headed west toward Pilot Mountain and the infamous Fancy Gap grade on Interstate 77 northbound, moving in heavy traffic and finding ample opportunity to use my left turn signal.

I was immediately comfortable with the unit’s passing power. And I took this as a harbinger of a relatively easy climb up the 7.5 miles of 6-percent grade that would greet me when I turned the corner just outside Winston-Salem and headed north.

Volvo designed its EGR engine without changing the existing design of its turbo, where horsepower gets the giant quantities of air it needs to perform. Volvo says its V-Pulse technology achieves EGR by harnessing naturally occurring engine pressure as a means to reintroduce up to 30 percent of the cylinder’s combustion by-product back into the intake-mixing chamber.

John Moore, sales engineer at Volvo, said, “The only moving parts are a reed valve and two control valves.

“The cost of the turbo is lower with V-Pulse and there is no training necessary for mechanics,” he added

Like Mack’s new EGR engine, typical turbo sounds are lacking in the new Volvo power plant, replaced by a slight whistle as the turbo responds to driver and engine needs. I found this interesting, since the turbo set up in the Volvo is different from any of the other new engines. There is sometimes a disconnect between sound and expectation in the Volvo, the real indication of performance being throttle response and power through the rpm range.

Although I did not bobtail in the Volvo, it is obvious from dragging a loaded 53-footer that new turbo technologies, introduced as part of a package to meet emissions standards, can make EGR engines quicker to meet horsepower needs. It makes sense that this happens, given that the EGR system is controlled not only by driver actions but also by the engine’s computer. The turbo is ready to respond to throttle pressure much more quickly. The V-Pulse system spools up prior to a driver mashing his motor so that the engine is ready to perform much farther down the rpm range. This gives the D12D excellent low-end torque.

The weigh station was under construction in North Carolina so I crossed the Virginia line with plenty of juice, ready to mosey on up to Fort Chiswell where I would do my flip.

The grade starts right there at the Virginia rest area and just keeps on going, far up into the Virginia highlands. I know this grade, I’ve lunked up it in a lot of different trucks, and I was expecting to get in the granny lane and stay there. But I passed a J.B. Hunt driver, who by the looks of the creases in his trailer was heavy, and pulled over in front of him. I never saw him again. I passed another truck a couple of miles farther up and managed to maintain my gear. Later, I shifted down and maintained a steady 40 mph to the top, with no undue rise in water or oil temp.

It was a bright blue day on Fancy Gap and I needed the air-conditioning. It kept me cool and worked without taxing the engine on a grade where a lot of guys will shut down their coolers to keep engine temps stable. I tend to agree with Volvo and Mack when they argue that, since they make both the engine and the rest of the truck, they may have advantages over truck makers who use engines from other companies when it comes to integrating new engines with other truck systems like cooling.

Fancy Gap gave ample opportunity to understand the power curve, which comes on at about 1100 rpms and is strong right up to 1900. This is one hill that makes you think you’re at the top once you get past the long straightaway where you can look over your shoulder and see the summit of Pilot Mountain. But there are a couple of valleys up there where you can be in a different gear than the one you used to pull the fat part of the hill. That’s how I know the power band is strong. On the way back, Pilot Mountain looks much closer, probably because you’re going down on to the Piedmont Plateau and the mountain is a landmark you’re headed for.

I did not use the cruise at all on the trip, and I drove like an owner-operator rather than like a fleet guy looking for a fuel bonus. I got a little over 5 miles per gallon on the 109 miles to Fort Chiswell and a little over 6 mph on the way back. It is difficult to assess fuel mileage given the effect of Fancy Gap both coming and going but I expect the fuel conscious can expect a few percent drop in efficiency with EGR involved.

Volvo has not increased oil capacity, however, which will save owner-operators money on drain intervals, nor has the company changed its drain intervals or its engine ratings. But Randy Bollinger of Volvo stresses the absolute necessity to adhere to preventive maintenance schedules. Volvo’s new engines are SAE certified for the B50 life range, according to Mike Cantwell, product applications manager, a standard equivalent to 750,000 miles.

It might well turn out that Volvo’s aerodynamics and the simplicity of its V-Pulse design will convince some owner-operators to give an entry into the emerging EGR market a try. Certainly a one-day ride does not answer all the questions, but this driver’s experience makes me believe the Volvo engine guys have done their homework.

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