The Evolution of the Powertrain
Powertrains have come a long way over the past few decades, with ever-improving technology fueling the internal combustion engine as well as driving several more carbon-friendly alternatives into the marketplace. For now, and the foreseeable future, the diesel engine reigns king, but that does not mean there have not been significant improvements made to the traditional powertrain over the years, many of which have helped reduce fuel consumption and made the jobs of technicians and fleet maintenance managers easier.
We spoke to a few industry professionals about what the current world of powertrains looks like, popular trends they are seeing today, common mistakes people make when it comes to spec’ing a powertrain, and how the engine and transmission have evolved over time.
One key difference Ron Duda, corporate sales manager of the truck and trailer division for Redhead Equipment in Saskatchewan, underscored is the change from the traditional 15-liter engine down to a 13-liter.
“Certainly, there’s a continuing exodus from the belief that 15-liter power is needed for every application to an understanding that technology has developed to a point where 13-liter technology will not just suffice, but perform really well,” said Duda.
Primarily focusing on Mack Trucks powertrains, Duda said today’s 13-liter engine can produce 505 hp and 1,850 lb.-ft. of torque, something that was traditionally only seen with a 15-liter offering. Duda said trucking companies hauling over the road across Canada would not normally even consider looking at 13-liter power, only 15, such as the ISX, DD15, and Volvo D16, a 16-liter engine.
“But thanks to new technology, that attitude has changed. “Many of them are right-sizing down to 13-liter power,” said Duda.
Jason Wheeler, vice-president of operations for Inland Kenworth in B.C., noted one trend he is seeing with today’s powertrains is downspeeding – getting the engine to rev as low as it possibly can – again in an effort to reduce fuel consumption.
“The idea is that every time a cylinder fires, it uses fuel,” Wheeler said, “so the fewer times the engine turns over in a given distance, less fuel will be used.”
Wheeler advises his customers to ask a lot of questions when enquiring into a new powertrain so they attain a full understanding of what they are getting, including how it will be spec’d to suit their intended application.
“Just because you have always spec’d a ratio, transmission, and engine horsepower doesn’t mean you will get the same results,” he said. “Engines are always changing as improvements are made and it is important to adapt everything else to the engine’s sweet spot.”
One of those questions should be an honest assessment of what you want to do with your truck.
“When asked what speed you travel at, 65 or 70 mph is not real,” said Wheeler. “You might have dreams of cruising the I-I5 to California at the speed limit, but this is rarely the case due to congestion and terrain. The speed you spend the most number of hours cruising at might be 55 mph, and if this is the case, spec’ to that mark.”
Wheeler said when powertrains are spec’d for higher speeds when a lower speed would be more suitable, the revs will be incorrect, and the driver will constantly be going down a gear and not staying within the engine’s sweet spot.
Bert Downton, regional used truck and trailer sales manager for Custom Truck Sales in Saskatchewan, said he is seeing a trend toward heavy spec’d trucks in Western Canada, typically 550 hp, 18-speed manual or automated manuals, and super 40/46,000-lb rear axles.
“For fleet customers, we work very closely with the manufacturer, mostly for fuel mileage, so typically a fleet would run 455 hp, 10/13-speed auto, lightweight 40,000-lb axles and high ratio gearing,” Downton said.
“The electronics of the engine/transmission take over for the most fuel efficient management of the powertrain.”
Due to the smaller size of the marketplace in Saskatchewan, Duda said at Redhead Equipment they do not focus on any one particular application when it comes to powertrains, but rather attempt to offer service to a wide range.
Duda said one of the main differences in North American powertrains over the past decade is a move toward integration, something he said has been heavily influenced by the global market.
“We do look
The Evolution of the Powertrain
very heavily on the integrated powertrain and then we have an option for numerous different rear axles and suspensions depending on application,” Duda explained, saying the option he works with today for powertrains is mostly being handled with the Mack mDrive (automated manual transmission), which is available in 13 and 14 speeds with creeper gears.
Duda said the North American market used to be unique in that it would have multiple engine manufacturers available to various truck builders – such as Mack, Cummins, Detroit, and Cat engines.
“Everybody is now going toward an integrated design, which really follows the rest of the world,” he said, pointing out that Cummins is the sole independent engine manufacturer left. (Cummins, too, is now taking an integrated approach to powertrain design, by recently forming a joint venture with transmission maker Eaton).
Another reason Duda believes this move toward integration is occurring is cost, as it was difficult and expensive for engine manufacturers to meet emissions standards with their engines and at the same time be able to integrate them with various truck manufacturers.
Downton said when it comes to choosing a new powertrain, some customers make the mistake of focusing primarily on the dollar factor and not on any change of application or potential resale value.
He also said there are more electronic assistance programs available today than there were 10 years ago, and there has been a demand for lighter, more efficient trucks.
In Canada, especially in the west where volatile oil prices often have an effect on the industry, Duda said many of his customers have become more diversified.
“They need a truck that is going to haul a flatdeck one day, pull an oil tanker the next day, pull a cattle pot the next, and so on,”
Duda said of his western clients. “It’s just the way business and industry is out here, so sometimes the truck is not necessarily 100% efficient and spec’d for the exact application that it’s in at that point in time, but it can perform a bunch of different types of tasks.” Duda said several owner-operators in Western Canada who worked the oil patch have spec’d their trucks with a small sleeper to enable them to haul other types of freight, like grain or fertilizer, when the energy industry takes a hit.
“They’re willing to give up that 800 lbs and $10,000 that they paid for the sleeper and the new truck to have that diversity,” he said. “It’s necessary for their survival and keeps as much diversity as possible.”
Wheeler cannot stress enough the importance of being as honest and accurate as possible when it comes to selecting the right powertrain and spec’s.
“Powertrains are now very complicated puzzle pieces, but as long as you provide all the correct data for your application then all manufacturers have computer models that will advise you on what you should have,” said Wheeler. “The key is giving the computer model the true facts.”
And don’t be afraid to ask questions if you’re not sure what you need.
(The previous article “The Evolution of the Powertrain” was archived on September 2017 via https://www.trucknews.com.)