Ford's PZEV Diesel Quest
By Bill Moore
Everybody knows diesels are dirty.
Everybody except maybe a bunch of folks are Ford Motor Company who have set themselves the laudable, if daunting, task of engineering the world's first Partial Zero Emission Vehicle (PZEV) diesel engine. The Dearborn carmaker decided to showcase their efforts, which are still a work in progress, by using what it calls is the world's first PZEV diesel engine to power the Lincoln Mercury Meta One Concept cross-over vehicle, now on display at the 2005 North America International Auto Show in Detroit.
Two years ago, EV World talked with David Wagner about Ford's Centennial concept vehicle, the Model U which boasted a number of sustainable innovations from its hydrogen-fueled internal combustion engine to its "Cradle-to-Cradle" materials developed byMBDC.
Now Wagner and his colleagues have created another ground-breaking vehicle, one that comes extraordinarily close to being the ideal pathway between today's gasoline-electric hybrids and the next generation of fuel cell-powered cars and trucks.
In his words, "this is a closer range vehicle that's part of our bridge from hybrids to hydrogen." Where the Model U and its successors at Ford showed it was possible to adapt a conventional IC engine to burn hydrogen in combination with either a hybrid-electric drive system or relying solely on a supercharger, the Meta One mates the 2.7L V-6 diesel engine just introduced last year in the European Jaguar and at Peugeot to a Ford hybrid-electric drive. This is a strategy that some studies suggest can produce a motor vehicle with nearly the same overall energy efficiency as current fuel cell vehicle technology, an idea Wagner confirmed.
Meta One's the Name, PZEV's the Game
The difference, of course, is that the fuel cell's only emission is warm water vapor, while even the cleanest diesel today still generates its share of pollutants. This is why, Wagner told EV World, his company has been investigating for years methods and materials to reduce diesel emissions and is, in fact, the point of the Mercury Meta One Concept program.
While Ford scientists and engineers have been working on cleaner diesel technology for sometime now, the effort to integrate it with Ford's successful hybrid-drive program is, according to Wagner, just a little over a year old. The company picked the Mercury brand in which to display the PZEV as part of its efforts to reinvigorate the Lincoln Mercury name plate. It's the Mercury Mariner that will shortly become Ford's second vehicle after the Escape Hybrid to be given a gasoline-electric drive option and will go on sale before the end of the year.
The Meta One isn't Ford's first diesel hybrid-electric vehicle. It, along with GM and DaimlerChrysler, relied on the same combination to power its one-of-a-kind Partnership for a New Generation Vehicle (PNGV) called the Prodigy. But where that vehicle's design goal was a family sedan capable of achieving 80 mpg fuel efficiency, the Meta One's goal is dramatically reduced emission of pollutants and climate altering gases and particulates.
"Our expectation here is that by the synergy between the engine advances and the hybrid function, we can find a way of decreasing overall tailpipe emissions and get to PZEV levels we've not achieved before," Wagner stated. While the Meta One pictured above is, in effect, a "static" display model incorporating numerous advanced automotive safety and convenience features, it shows the direction Ford research is progressing. Wagner and his colleagues told me that although they haven't as yet achieved PZEV levels in a completed prototype system, they are continuing development work to eventually reach that level, with nitrogen oxide or NOx being the biggest challenge confronting the program.
As the team explained, at the urging of carmakers the California EPA and its Air Resources Board created the PZEV category for very low emission internal combustion engines, which while not a clean as the Zero Emission Vehicle or ZEV class set up for battery electric cars in the 1990s, still was significantly better then conventional engines.
"It represents a challenge to get very close to zero for a fairly conventional or piston engine powertrain. It's a substantial challenge below the average of vehicles being sold today and will be sold in California. But it represents an on-going challenge to see how low we can, in effect, get."
Carmakers have already achieved PZEV levels in some of their gasoline-engine models that are sold in California, and Wagner assumed that if his company can engineer diesel-hybrids that attain the same emissions standards that they should be able to be sold in California, which classifies diesel emissions as carcinogens.
"We would certainly expect that a vehicle that could achieve these emission levels, could and would be sold in California."
There are several reasons why you'd want to marry clean diesels and hybrid drives. Diesels are traditionally more fuel efficient than gasoline engines, which accounts, in part, for their enormous popularity in Euorpe (aided by favorable tax breaks and subsidies). They also have greater torque and is why they are used in trucks. Hybrid-electric drives achieve their efficiencies by enabling designers to utilize smaller engines operating at improved outputs, along with being able to turn the engine off and on to conserve fuel and cut emissions. Hybrids also make possible the recapture and reuse of some of the vehicle's kinetic energy through regenerative braking.
Bringing the two technologies together should, in theory, at least, result in an extraordinarily efficient powerplant combination.
Mercury Meta One's PZEV diesel hybrid electric powertrain
Dealing With NOx
A significant part of the emission reduction system comes from after-treatment of the exhaust. As Dick Baker explained, there are two ways to tackle the problem: NOx absorbers or traps and aqueous urea injection, the later favored by the Ford team. What they are envisioning is a system that injects an addictive of urea, a liquid form of ammonia. This reacts with the nitrous oxide in the exhaust, neutralizing it. The ammonia would then be recaptured before it left the tailpipe and reused.
"Ammonia is useful," Baker said, "because it's very useful as a reducing agent to reduce the nitrous oxide. Now that's a bit complicated, and of course, we certainly don't want to suggest putting ammonia into the exhaust and let it escape from the vehicle. We certainly have to make sure that no ammonia escapes the vehicle and there's no odor associated with the use of that material. That's one of the technology challenges, but we think that's possible to do.
"This is technology that is proceeding in Europe on trucks," he continued. "I think this month they are launching products... It is used widely in stationary generator sets... so it's not completely unique to this program. But it's a little bit difficult to program into a vehicle, as it has to be provided to the vehicle at regular intervals; probably service intervals, and we have to figure out how to make all that work."
He said if Ford can get the system "right", it will reduce NOx emissions by at least 90% overall.
He added that the challenge is not only figuring out how to make the NOx emission control system work on a production vehicle, but the company also would have to set up a distribution network to supply the additive to its dealers and the after-market.
Designed for Future Fuels
Another important element in the drive for a PZEV diesel is the fuel itself. The engine in the Meta One is designed for low-sulfur diesel, which is widely available in Europe, and will be across North America after 2007. This is the presumed starting point for the PZEV project.
To its credit, Ford is looking beyond conventional low-sulfur diesel to increasing availability of biomass-derived fuels. Here, the team is confident that they also can make the technology work on renewable biodiesel, giving the system the added benefit of not only reduced CO2 emissions, which is an advantage of conventional diesel fuels, but also getting ever-closer to being CO2-neutral.
"While the concept does not depend on the use of a very special fuel, it can accommodate and is consistent with the long-term use a renewable fuel that could reduce the CO2 emissions, as well as the regulated pollutants."
Towards this end, Ford is working with BP to identify potential fuels formulated from increasing percentages of biomass sources.
Low Emission, Not High Mileage, the Goal
I asked the team what consumers might expect in terms of improved fuel economy from this PZEV diesel hybrid-electric system, assuming that the system might go into future production. While they estimated it would probably be about 25 to 30% more fuel efficient than a comparable gasoline engine simply because of the improved efficiency of the diesel, Zafar Shaikh stressed that unlike the Prodigy, where the goal was 80 mpg, the object of the Meta One program is dramatically reduced emissions. No one was willing to project how much improvement in fuel economy hybridization might add, in part because they are looking at it as another tool for helping reduce emissions, rather than reducing fuel consumption.
Hazy Crystal Balls
A PZEV diesel hybrid-electric with efficiencies approaching that of a fuel cell vehicle is clearly an attractive technology, especially if it someday can run off of farm-grown, bio-sustainable fuels. So, I asked Wagner and his colleagues to peer into their "crystal balls" and hazard a guess as to when this technology might become available and how much it might cost.
They responded that since the Meta One concept car showcases a number of different technologies including a modern, V-6 diesel engine, a hybrid-electric drive and an advanced emissions after-treatment system, they expected individual components will be introduced in future Ford products in the next five to ten years. But as for when all three would be combined in a production vehicle, Wagner said his crystal ball simply isn't clear enough.
As to the question of future costs, he cautioned me to not add up the separate costs of each individual component system to arrive at a potential cost of a complete powertrain. Just because a hybrid system and a diesel engine might add three thousand dollars each to the price of a vehicle, this shouldn't imply that together they would add $6000 to the sticker price.
"We try very hard for synergy," Baker assured me. "But as David said, we really don't know how to put a cost on that overall package. Part of the learning we have to do with our research concept is to determine to what extent we need all those features and their value."
Advanced Safety and Communications Features
Beside the PZEV diesel hybrid-electric powertrain, the Mercury Meta One also showcases two other advanced concepts.
On the vehicle safety front, Ford installed a lane divergence warming system that activates a vibrator in the driver's seat that simulates a highway rumble strip to alert a sleepy or distracted driver when they are veering out of their lane. The collision mitigation braking system senses if a frontal collision is imminent and if the driver doesn't appear to be responding, it will automatically apply the brakes, reducing the speed of the vehicle by five or more miles per hour.
The Meta One also boasts some fascinating electronic communications concepts including a KDA or "key-fob digital assistant" that digitally stores a host of personal settings and preferences from navigation settings to the owner's favorite radio stations. The car also sports new wireless networking technology that will let the vehicle navigation system communicate with a city's traffic control system to monitor road conditions and suggest alternative routes to avoid congestion. [Watch for an upcoming "Future in Motion Moment" MP3 Podcast for more details on this feature].
While the folks at Ford are clearly excited about their PZEV diesel program and believe that interest in modern diesel engines is growing in America, they acknowledge that the current "aberration" in diesel fuel prices may cool some of that interest. Historically, for the last five to ten years, diesel fuel has cost 5-10 percent less than unleaded gasoline. That trend reversed itself in 2004 with diesel fuel now costing more than gasoline. When or if pricing will return to its historic relationship is a question they deferred to the oil companies.
Finally, Wagner agreed to talk to EV World again after the Detroit Auto Show to follow-up on the public's response to the car and Ford's other "green" vehicle offerings, which include a hydrogen-fueled shuttle bus that will be available for sale and the announcement that it will be offering five new gasoline-electric hybrids starting with the Mercury Mariner late this year.
Ford is clearly serious about improving its environmental image and is investing time, talent and capital towards that end, perhaps more so than any other North American auto maker. Whether or not they will someday build a PZEV diesel hybrid for the consumer market is yet to be seen, but its encouraging to see they are exploring all these options from hydrogen fuel cells to hydrogen-fueled IC engines to biodiesel hybrid-electrics.
Now if only they hadn't sold Th!nk.