You are using an older browser version. Please use a supported version for the best MSN experience.

Keep on Truckin' ... At Double-Digit MPG - Technologue

Motor Trend logo Motor Trend 8/6/2015 Frank Markus

You'd be forgiven for missing a piece of government news at the end of June that was drowned out by the considerable commotion caused by the momentous Supreme Court verdicts. The EPA's proposed fuel-efficiency and carbon-pollution standards for heavy-duty trucks didn't make front-page/top-of-the-hour news headlines, and because very few of you (statistically speaking) drive big-rig trucks for a living, you probably didn't pay much attention. But the implications are huge, and they will affect all of us.

Research

These Phase 2 standards build on those phasing in between 2014 and 2018 that will result in a 16 percent reduction in fuel use relative to 2010 levels. The new ones take effect from 2021 to 2027, reducing Class 7 and 8 semi-tractor consumption by a further 24 percent via any means feasible: aerodynamics, engine, driveline, low-resistance tires, etc. Trailers will also be tasked with contributing an 8 percent reduction in consumption with aero aids, self-inflating low-resistance tires, and weight reduction. If an average 2010 big-rig was getting 6 mpg, the 2027 one should be getting better than 10. The EPA makes some impressive claims for how this proposed legislation (which covers most heavy-duty pickups, vans, work trucks, and busses) will reduce energy use over the working lifetime of the entire 2027 new-truck fleet: 1 billion metric tons less CO2, $176 billion less spent on fuel, and 1.8 billion fewer barrels of oil consumed. That's about equal to the CO2 emitted to power every U.S. household combined per annum.

Read about the best trucks for work and towing in this Motor Trend list HERE.

MotorTend Image© Provided by MotorTrend MotorTend Image Car buyers in a cheap-gas world care little about CAFE regs and are resistant to paying for modest fuel-economy gains, but fuel costs are a huge budget item for long-haul truckers. These regulations are therefore meeting with less resistance, in large part because the estimated cost of compliance is forecast to be paid back by fuel savings in about two years—good news for long-haul truck purchasers, who don't typically replace their trucks until after four or five years.

Coincidentally, at about the time these new regs were announced, I had a chance to chat with David Johnson, CEO of Achates Power Inc. about an engine designed to help meet these regs. I covered it briefly in an April 2014 SAE roundup. His company is now working with multiple manufacturers to develop and license its novel two-stroke opposed-piston diesel, which can replace a conventional four-stroke diesel improving fuel economy by a reported 20-30 percent.

MotorTend Image© Provided by MotorTrend MotorTend Image Each cylinder is fitted with two opposed pistons. Unlike the similar EcoMotors and APT opposed-piston opposed-cylinder (OPOC) designs, which arrange pairs of opposed-piston cylinders around a central crankshaft (using really long connecting rods for the outer pistons), Achates uses a crankshaft at each end of the cylinders, gearing them together on one side of the engine. Nearing bottom dead-center of their travel, each piston exposes a ring of intake or exhaust ports, with the latter exposed slightly sooner. Turbo- and supercharged intake air pushes the exhaust out, and direct fuel injection very near top-dead-center ensures that very few unburned hydrocarbons flow out with the exhaust.

With a lower surface-area-to-cylinder-volume ratio, the design has much higher thermal efficiency and lower combustion temperatures, which places less stress on the catalyst's precious metals that oxidize the various pollutants. Lower peak pressures and fuel injectors aimed to miss hot surfaces lower NOx and particulate emissions. These features reduce exhaust after-treatment cost and size by 30 percent. Deleting the valvetrain and cylinder head(s) lowers tooling cost and roughly offsets the parts cost of the extra crankshaft and its geartrain. Machining and assembly are largely adaptable to current factory equipment.

Achates envisions engines ranging from one cylinder/50 hp to 12 cylinders/1,000 hp, but expect the first ones to look something like its 4.9-liter, 275-hp, 811-lb-ft three-cylinder, which is claimed to be 20 percent more efficient than Ford's 6.7-liter commercial PowerStroke turbodiesel V-8 (300 hp/660 lb-ft). If Achates keeps the cost penalty as low as Johnson suggests, we can all expect to be paying a little less for everything that gets shipped, come 2021.

MotorTend Image© Provided by MotorTrend MotorTend Image More from Technologue:

Space-Truckin-man1© Provided by MotorTrend Space-Truckin-man1
AdChoices
AdChoices

More from Motor Trend

Loading...

image beaconimage beaconimage beacon