April 1, 2004
An interesting technological achievement is taking place right under the noses of light-truck users today and the reason is pretty simple: While government regulations are mandating a decrease in engine emissions, customers are demanding an increase in power and performance. The OEMs must figure out how to ensure that light-truck engines meet both of those needs without the customer noticing any changes.

An interesting technological achievement is taking place right under the noses of light-truck users today — and the reason is pretty simple: While government regulations are mandating a decrease in engine emissions, customers are demanding an increase in power and performance. The OEMs must figure out how to ensure that light-truck engines meet both of those needs — without the customer noticing any changes.

“Transparency is the main issue,” says Doug Scott, marketing manager for Ford Motor Co.'s commercial light-duty products. “No one will accept lower performance due to tighter emission rules. In fact, we're going to need more performance. We can't give the customer less power, we can't pass on too much of the cost, and we must meet the emission laws. That's quite a challenge.”

“Emission compliance is a big deal,” says Tom Brosey, executive director, light-duty automotive marketing, Cummins Engine Co. “The constraint we keep getting into is there's a trade-off in performance and/or fuel economy for lower emissions. That's the way the physics work. So emissions control is less a ‘can we do it’ issue than how attractive can we make that lower-emission product to the customer.”

“Performance is the biggest deal for these vehicles,” says Pat Charbonneau, chief technology officer for International Truck & Engine Co.'s engine division. Light-truck users “want plenty of torque, plenty of power, yet their engines must comply with a variety of new emission rules. But we're doing it. And customers, I think, are going to like what they see in terms of both performance and sociability as we meet ever stricter emission standards.”

Both gasoline and diesel engines powering light trucks, as well as the fuel they burn, are under the gun in terms of reducing emission levels.

For new gasoline-powered light-duty trucks under 6,600 lb. GVWR, oxides of nitrogen (NOx) emissions must drop to 0.07 grams per mile (g/mi.), with particulate matter (PM) capped at 0.02 g/mi., by 2007. Known as Tier 2 rules, they will be phased-in between 2008 and 2009 for light-duty gasoline powered vehicles over 6,600 lb. GVWR. For vans and SUVs, the Tier 2 NOx limit is set at 0.09 g/mi‥

The Environmental Protection Agency (EPA) also stipulates that the emission control technology used on light-truck engines must keep pollution at the mandated level for an estimated lifecycle of 120,000 miles.

Diesel engines in trucks over 8,500 lb. GVWR, however, must meet the same emission standards as their big-bore brethren. Starting this year, diesel engines in this class can emit no more than 0.10 grams per brake horsepower hour (g/bhp-hr.) of PM; 2 g/bhp-hr. oxides of NOx; and between 0.4 and 0.5 g/bhp-hr. of nonmethane hydrocarbons (NMHC).

In 2007 those levels drop another huge notch: PM to 0.01 g/bhp-hr.; NOx to 0.2.; and NMHC to 0.14. The PM requirement will go into full effect in 2007, with the NOx and NMHC requirements phased-in between 2007 and 2010. EPA expects the emission control technology for those diesels to function for 400,000 miles.

EPA has also mandated a dramatic reduction in the amount of sulfur allowed in both gasoline and diesel fuel. This year, sulfur in gasoline is being cut to an industry average of 120 parts per million (ppm), with a cap set at 300 ppm. By 2006, those levels will be lowered again, down to an average of 30 ppm, with a cap of 80 ppm. Changes in diesel fuel become effective June 1, 2006, when the sulfur content must drop to 15 ppm from the current 500 ppm.

“The end result of these efforts is that diesel engines are becoming more like gasoline engines in terms of environmental impact,” says Cummins' Brosey. “The key is how to boost the performance aspects of the engine — what we call its ‘capability’ — at the same time.”


Yet even as light-truck OEMs come to grips with lower engine emission targets, they are also trying to meet ever-rising demands from customers, according to Gary Cowger, General Motors' North America operations.

“Customers have almost too many choices. And that's a challenge if you're trying to get them to buy yours,” he explained in a speech at this year's North American International Auto Show. “No segment spawns more body styles, duty configurations and powertrains than full-size pickups.”

One of the biggest challenges from Cowger's viewpoint is that meeting the demands of customers, especially in terms of providing more engine power, puts OEMs at odds with many powerful interest groups.

“When we step back and take a look at the big picture surrounding fuel economy, vehicle emissions and the environment, we see that there are dozens of interest groups that take a view on how we should address these important topics,” he says. “Frankly, not all these groups see things the same way. Some groups are primarily concerned with U.S. energy policy, some with national security, some with vehicle emissions, some with broad environmental impact,” Cowger points out. “And I can tell you that there is no single integrated solution that fully satisfies all of these sometimes competing interests.”

From GM's perspective, there are three primary forces driving light-truck engine development today. “First, we have to offer products that customers really want to buy. Because if no one buys your products, your technology has no real impact,” Cowger says.

“Second, we need to meet some basic business objectives, like selling at prices that customers are willing to pay, and for us to be able to produce at costs in line with those prices,” he adds. “And third, as an industry we have a responsibility to continue improving vehicle emissions and fuel economy.”

However, for the commercial segment of the light-truck market, Ford's Scott says that engine torque trumps fuel economy most of the time. “The most important thing for work truck buyers is torque, especially at the low-end,” he says. “In general, fuel economy is not the highest priority for these buyers. These are work tools, after all.”


Because they crank out more power and get better fuel economy, diesel engines have been the powerplant of choice for light trucks with GVWRs over 8,500 lb. But as diesel engines become cleaner, OEMs are starting to look at whether they might be more attractive to the under-8,500 lb. segment. And it's a topic that's generating controversy in some quarters.

“In heavy-duty pickups above 8,500 lb. GVWR — three-quarter and 1-ton models — diesels have 60-65% market share overall,” says Cummins' Brosey. He says the reasons for diesel's dominance are pretty straightforward: the ability to haul more combined weight in terms of towing and truck-bed capacity, better fuel economy under load, better overall fuel economy than gasoline (as much as 50% depending on application), and durability.

“Diesel engines are designed with a longer lifespan — we have Dodge Ram customers that have put 1-million miles on these engines in commercial on-highway use, such as car hauling,” Brosey says.

Allen Schaeffer, executive director of the Diesel Technology Forum, says, “Diesel engines of today produce 20% to 40% better fuel efficiency on average than their gasoline counterparts. By 2007, new diesel vehicles will be certified to meet the same emission standards as gasoline vehicles. Consumers and regulators — even those in California — are increasingly recognizing the superior benefits of diesel technology.”

Two issues that have stymied further penetration of diesels into the light-duty market, especially in the under-8,500-lb. category, are price and “sociability,” with the latter referring to the noise and vibration generated by diesel engines, as well as the strong odor of the fuel.


“Typically, a diesel engine comes with a $5,000 premium — even higher in some cases — versus a gasoline model,” Brosey explains. “But if you own the truck for a long time, you get that premium back in terms of better fuel economy and higher residual value.”

“The overall sound quality continues to improve and the smell of a diesel is less [apparent], due in part to emissions improvements,” says International's Charbonneau.

Not everyone is sold on the diesel engine, however. Environmental groups, for example, argue that it would be cheaper to modify gasoline engines using existing technology to improve both fuel efficiency and emissions levels. They also feel that the tax incentives for clean-diesel being discussed on Capitol Hill are taking attention away from other fuel and emissions-reduction technologies, such as that used to create hybrid vehicles.

The debate over diesel's cleanliness is but one example of how engine development in the light- truck market has a much higher profile than in the past, says Bruce Jentleson, director of Duke University's Sanford Institute of Public Policy.

“New vehicle technology, especially in the global marketplace, raises many policy-related questions,” he says, noting that with funding from GM, Duke is doing research on the use of hydrogen-powered fuel cells in cars and trucks.

“How will the development and implementation of such initiatives affect environmental policy, the international energy economy, and political and regulatory decision-making?” Jentleson asks.

“These are compelling and complicated issues.”

Powering up

Light-truck operators have long known that vehicle power has increased. Now EPA has the data to back this up. A report of trends in light-duty vehicles from 1975-2003 by the agency's Office of Transportation & Air Quality determined the following:

  • Horsepower increased almost 93% during the last 15 years. Specifically, ratings for 4-cyl. truck engines jumped an average of 44%, from 47 to 140 hp. Six-cylinder pickup engines jumped 30%, from 142 to 185 hp. And horsepower for 8-cyl. pickup engines rose 47%, from 180 to 240.

  • Truck weight increased by 24% over the last twenty years;

  • Zero- to 60-mph acceleration rose 29%;

  • Fuel economy has remained largely unchanged, averaging between 17.3 and 18.4 mpg over the last 15 years.

Scientists weigh in

Environmental groups such as the Union of Concerned Scientists (UOCS) are ratcheting up their efforts to reduce air pollution generated by light trucks. The reason is simple: They account for more than 48% of all new vehicles sold in the U.S.

According to the UOCS, light trucks produce more pollution and consume more fuel (per vehicle) than cars. The group's stats say the average light truck spews 129 lb. of smog-producing exhaust annually, while the average car produces 88 lb. Average yearly gasoline consumption is 702 gal. for light trucks, compared to 492 gal. for cars.

The UOCS says changing the technology of gasoline-powered light-truck engines is the cheapest way to decrease emissions in this vehicle category.

In a California test program, the UOCS was able to modify a Ford Expedition to reduce exhaust pollution by 90%. All it took was to reprogram the air/fuel system and add a more durable catalyst.

“The total added costs of these improvements were estimated to be about $200 per vehicle on a full-size SUV,” said the UOCS. “This is one of the cheapest air pollution mitigation investments that can be made.”

Hybrids ahead?

General Motors is one of a number of OEMs convinced that hybrids offer the best opportunity to improve fuel economy in light-duty trucks.

The OEM now offers a hybrid system that combines a 5.3-liter V8 with an electric motor for its full-size Chevrolet Silverado and GMC Sierra pick-ups, says Rick Wagoner, GM's president and CEO. The hybrid models will be available for SUVs such as the Chevrolet Tahoe and GMC Yukon in January 2007.

“These hybrid systems will create a 10-12% savings in fuel economy,” Wagoner says. GM also plans to introduce a Saturn VUE with an Advance Hybrid System in the second half of 2005 that is expected to achieve fuel economy gains of up to 50%.

Wagoner stresses, however, that hybrid development for light trucks is still in its infancy and will need government help to survive.

“In today's market, demand for hybrid vehicles is low,” he explains. “Because hybrids can cost up to several thousand dollars more than conventional powertrains, we believe offering different hybrid approaches, in a range of popular vehicles, is the best way to fully explore the market potential for this technology.”

DaimlerChrysler agrees that cost is going to be the big hurdle for hybrids. Its Dodge Ram gasoline/electric hybrid, which couples a three-phase electric induction motor with a 3.9L V6 engine, will add $5,000 to the base price of the vehicle.

“It's clear that government policy will have to play a big role in the development of the hybrid market, whether [through] mandatory use of hybrid vehicles in government fleets or through extensive consumer tax credits to encourage retail sales. In our view, both of these will be required — and maybe more.”

About the Author

Sean Kilcarr | Editor in Chief

Sean previously reported and commented on trends affecting the many different strata of the trucking industry. Also be sure to visit Sean's blog Trucks at Work where he offers analysis on a variety of different topics inside the trucking industry.

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