Phase 2 of the fuel-efficiency/greenhouse gas regulations will soon be unveiled, demanding even tougher, more stringent CO2 and fuel-consumption reductions of medium- and heavy-duty trucks.

Engines and vehicles are tested separately in Phase 1, but there are those who urge that just one test, with engines rolled into the whole truck like any other component, is the better approach.

As things stand now, engines are tested on a dynamometer as they have been all along, and Cummins thinks it should stay that way, according to Brian Mormino, executive director, worldwide environmental strategy and compliance at Cummins.

Among other reasons, Mormino told us in a lengthy interview, this would preserve spec'ing flexibility for truck buyers and ensure repeatability in the testing process.

Trucks, on the other hand, are tested by way of computer modelling in Phase 1, with some inputs coming from on-track trials using standard SAE protocols and that data then fed into the modelling software. Daimler and Volvo (including Mack), the only fully integrated OEMs, are arguing that a single all-inclusive test would be simpler and more cost-effective.

Mormino says the implementation of Phase 1 was pretty much seamless, and he attributes that success largely to the continued use of familiar regulatory tools and testing methods that had been in place for decades. For 30 years engine makers have tested NOx and particulates on the dyno, and it was easy to include CO2 as well.

"We just added CO2," Mormino says, "which means that we allowed all that diversity to continue in the marketplace because the engine is certified to operate in a wide range of vehicles and applications. So customers and end-users still have all the choice that is really, really important... in terms of all of their preferences and the types of work they have to do. The regulation didn't... limit their choices."

Perhaps a more compelling argument is the one he makes about the huge number of fuel-economy variables when a truck is put to use. Like driver skills, terrain, trailer type, highway or city, load, and countless others.

"That is a challenge for any type of regulation that tries to drive technology on vehicle aspects that are highly variable," Mormino says. "And the way that the regulation attempted to deal with that is that it separated out the most certain aspect, the engine, and provided a much brighter focus on something you can repeatably and accurately measure and do so in a way where it can be enforced."

On the other side of this argument sits DTNA's Sean Waters, as well as the Volvo Group's Tony Greszler.

"Our goal has always been to provide our customers with the lowest total operating costs to increase their revenues, and the most effective way to do that has been to provide better fuel efficiency," says Waters. "Regulations have interfered with this goal in the past where criteria-pollutant emissions control technology had a great negative impact on fuel economy. 

"It's critical that regulations to reduce fuel consumption do not in actuality result in negative impacts on real-world fuel efficiency gains, and this is where the current separate engine standard program has failed. Engine test cycles are based on historical operating data and cannot reflect changes in engine size, powertrains, or vehicle power demand and do not accurately represent the fuel used in the real-world, nor were they ever designed to do so," Waters suggests.

"DTNA believes the best way to ensure that the Phase 2 regulation provides a total-cost-of-operation benefit to customers is to give manufacturers the ability to focus on improving the entire vehicle as it operates on the road and in the application for which its customers want to use the vehicle. Any regulation that doesn’t give manufacturers the flexibility to meet it in the manner that works best for our customers, results in vehicles that customers can’t afford, or doesn’t provide sufficient real-world payback and risks creating a pre-buy prior to the regulation becoming effective."

Waters goes further, saying that the tests for criteria pollutants -- NOx and PM --  are based on a test designed in 1990 or 1991 "when trucks  had higher horsepower, more torque. It was just a different way of operating an engine. The test was never designed for CO2." Nor was it designed to measure fuel economy, he adds.

He figures the test was used for convenience in Phase 1 to get a rule done quickly.

At Volvo Group North America, Tony Greszler is vice president of government and industry relations, and he's the point man on Phase 2 rules.

"The bottom line here is that the engine test doesn't test the engine the way it runs in the truck," he says. "It's impossible for any engine test to do that. And it also doesn't account for the impact of the engine on the rest of the truck.

"The technology of most concern is what we call waste-heat recovery," Greszler goes on, and we'll explore than in the next installment of this series.