Come to America

sphynix

In Europe today, conservative numbers put the market penetration of diesel passenger vehicles at 40 percent .With some individual countries-France, for example-seeing as much as 60 percent. At the same time, diesel penetration in the North American passenger vehicle market is less than 1 percent.
Volkswagen has demonstrated a North American interest for diesel vehicles smaller than 8,500gvw-itoffers diesel versions of its Jetty, Jetty wagon and golf, with plans to offer diesel new Beetles-but at this point, it stands alone.
If diesels are so popular in Europe, why then are their numbers practically non-existent in North American?
Diesel technology has come a long way from the ill-fated attempts in the 1970s and 80s to introduce diesel passenger cars .Many consumers in North American have a dated image of the loud, “dirty diesels” first offered here by car makers. But those days are long gone. Today, as proven in Europe, diesel are clean and efficient and offer a performance that is unmatched by a gasoline engine.
“Most people don’t really have a feel for what modern diesels are like because they haven’t experienced them,” says Bernard Robertson, senior vice president for engineering technologies and regulatory affairs at DaimlerChrysler. “The major enablers to making diesel engine systems as slick as they are now have been the advances in control systems, the fuel injection systems, the shift to common rail, very high injection pressures and the increasing sophistication of machining of injection nozzles, together with the high pressures to improve atomization.
“There has been dramatic change in the engine control systems,” Robertson adds. “I’d say we are at plateau at the moment, where there are a lot of very slick, refined, pleasant high output diesels which all share, broadly speaking, a similar architecture. The engines are comparable, they are all using high-pressure common rail, and they are typically all using pilot injection. ”
“I think that everyone is now on the cusp of the next significant move which will probably be another increase in injection pressure, another refinement in nozzles, and almost certainly multiple pilot injections instead of one pilot injection.”
Gary Smyth, engineering director, GM power train, also cited the growing sophistication of diesel technology. “We are now looking at turbocharged with intercoolers with variable geometry turbines,” he says. “If you look at the performance, we are now up to 60, 70, 80 hp per liter for those engines.”
Though that high-output technology has obviously been successfully demonstrated in Europe, the U.S. still appears to be a few years away from seeing large volumes of under8, 500gvw diesel vehicles. Besides the daunting task of changing the public’s mind, diesels in North American face other challenges, specifically emissions regulations and fuel issues.
EmissionsLooking at the world situation, it should come as no surprise that the European and North American look at the subject of emissions from different perspectives. In Europe, the focus is NOx and particulate matter (PM). In Europe, emissions standards are promulgated through the European Union. In the U.S., The Environmental Protection Agency (EPA) has primary responsibility, but in many cases, follows the lead of the California Air Resources Board (CARB).Because of air quality issues unique to California, CARB has been, in many cases, the tail that wags the emissions dog in North American.
There has been some general movement toward “harmonization” of emissions standards worldwide, but progress toward that goal has not been especially swift. That alone makes it difficult for diesels to freely move between global markets.
“In Europe, when people think clean, they focus on global warming and that is carbon dioxide, which is fuel economy,” says John Koszewnik, director of diesel engines at Ford Motor Co. “And there, diesels have a 30 to 40 percent advantage. In the U.S., the clean thought is led by California, and there, they’re not so worried about global warming. The CO2 they produce goes over the mountain. They’re worried about NOx.”
“Everyone in the world is working on how to reduce NOx and particulates,” adds Robertson. “The popular approaches to particulates are either further improvements in refinements in engine control to reduce the engine-out particulates combined with very clean fuel, or possibly synthetic diesel fuel or bio-diesel fuel. Any of those things seems to have the potential to meet the particulate standards.”
Robertson also cites particulate filters to reduce PM, which he says has “obvious merits but also some challenges.”
“It is costly,” he notes, “and you do have to regenerate. You have to find some way to dispose of the particulates. There is no complete consensus on how to do that successfully. And of course, during the time that you are regenerating the filter, potentially you are emitting something and the EPA requires you to measure that.”
Progress has been made, as over the last 10 years particulate emissions have been reduced by about 90 percent in diesel engines in Europe. “There has been significant advancement through combustion improvement,” says Smyth. “Additional improvements can be made and are being investigated though improved combustion.
“But also, you are now seeing the introduction of diesel particulate traps, or DPFs. The DPFs will reduce particulates by another 90 to 95 percent over today’s rail emissions. So with the introduction of DPFs, the particulate issue basically becomes a non-issue.”
On the NOx side, the most popular candidates are either NOx reduction catalysts or absorbers, which, according to Robertson, have been demonstrated experimentally. Yet it’s an unproved technology, as no one has successfully demonstrated NOx absorbers with the kind of durability and reliability that would be required for use in the real world.
Another emissions reduction candidate is selective catalytic reduction, (SCR) in which a reagent or reluctant, such as urea or ammonia, is injected into the exhaust stream, causing a chemical reaction that reduces NOx levels dramatically. There systems have been successfully applied to large, mostly non-mobile engine systems, such as those used for power generation. Yet, some point to the addition of the SCR system and the requirement to reload or refill the reagent supply, as drawbacks to applying it to mainstream passenger vehicles.
“The Europeans are quite enthusiastic about urea selective catalysis, and it has been demonstrated that it works,” says Robertson. “People know how it works and why it works and there are systems that that have been demonstrated that will successfully meet the very low emissions standard. But the EPA, up to now, has been very cautious with its view of those systems. It hasn’t exactly banned them, but it has said that it is not at all convinced that it is the way to go because it relies on the customer to keep the urea system charged. The EPA doesn’t believe that the general public would necessarily do that.”
According to Koszewnik, a key challenge to diesel is what is done to the basic engine design to reduce NOx emissions. He notes that “anything you can’t clean up in the base engine needs some sort of exhaust after treatment system that has an efficiency that allows you to meet the tailpipe requirements.”
Koszewnik believes that, in terms of diesel exhaust after treatment technology, we are roughly at a similar stage to where gasoline engines were five to seven years ago. “If you look, you’ll find that we are making major improvements with control strategies and the gasoline engine world that allow us to get higher heat fluxes to get quicker light-offs so that we can use reduced amount of precious metals,” he says. “I think we are relatively immature in terms of diesel exhaust after treatment and that we will find lower cost ways of putting the product out there that will meet the requirements without burdening the customer with costs.”
FuelSome argue that fuel-and specifically fuel costs-has a lot to do with the popularity of diesels in Europe. In the U.S, gasoline is cheaper than bottled water and fuel economy isn’t an especially high priority. In Europe, where fuel-and particularly gasoline-is generally much more, the increased miles per gallon offered by a diesel power train help offset the price premium associated with opting for a diesel engine.
“In Europe, fuel is close to $4 per gallon,” says Smyth. “Looking at it from an economic standpoint, if you look at the additional cost of a diesel engine, the premium payback time for a car with 30 mpg fuel economy is about 30,000 or 40,000 miles. In North America, because of low fuel costs, you’re looking at 250,000 to get a payback in the extra premium you pay for a diesel vehicle.”
The quality of fuel is another challenge for light-duty diesel engines in North America. The smaller diesel engines that are being used in Europe rely on low sulfur diesel fuel, which is essentially the standard. While it is available on a limited basis in North America, it won’t be widely available in the U.S. until 2006.
“We’ve had a lot of dialogue with the regulatory agencies and with the oil companies,” says Robertson. “We were strong supporters of the EPA’s rulemaking move to require low sulfur gasoline and diesel.
“There is a reluctance to invest when you don’t have to and the oil companies have the same reluctance anyone else does to making an investment if they don’t see a direct return in the investment. There are several oil companies that have started to make available low sulfur fuel. BP has made a commitment to make low sulfur fuel available in 40 cities around the world, with several are in the U.S. and they plan to beat the 2006 deadline.”

Diesel and the Big3

As the popularity of diesels continues to grow in Europe, the Big 3 are eyeing North American as possibly a fertile new ground for the technology. Daimler Chrysler, a strong proponent of diesels, is the fist to put its words to action by announcing plans to introduce a diesel Jeep Liberty and a Mercedes E320 CDI to North America in 2004. DC plans to start with 5,000 diesel Jeep liberties that will be built in Toledo, Ohio, and a “similar” number of Mercedes E320 CDIs that will be built in Germany.
“We are going to have to increase awareness and create demand,” says Robertson. “We look back at our experience with a Cummins diesel which we put in the Ram pickup. We do close to 130,000 per year now. That didn’t happen overnight. It gradually built up. The product got better and better and awareness grew. We are tying to start out with a reasonable volume of light duty diesels and go from there.”
While Ford has announced plans to introduce a diesel Focus to North America, the timing of that introduction and the planed volumes are closely guarded secrets.
“We are seriously studying the possibility of bring a diesel focus to North America,” says Koszewnik. “Ford produces around 1.1million diesel engines annually.”
“It’s natural that diesels are going to come to the U.S. in high volume in the near future. The manufacturers who are going to ride the wave are going to be successful, just like they were successful in Europe. Ford is tiding that wave right now, and we are going to do our best to make sure we ride that wave in North America.”
General Motor continues to break new ground in Europe. In December, Opel introduced the new Astra 1.7 CDTI, the first diesel to comply with Euro IV emissions standards. But when it comes to North America, GM says it is not prepared to comment.
“GM has the capacity for about 107 million diesels annually,” says Smyth. “As we look at Europe and Asia pacific, North America is still an unknown as to how successful diesel would be in our market, given those stringent emission standards and give the economics around fuel costs.”
“We can introduce a diesel vehicle to North America today,” says Smyth, “the question is can you keep them in production after 2007 (when the next tier of EPA standards is implemented). At this stage, we are not prepared to make any announcements. We are putting tremendous effort into developing the right system that would allow us to be in the market beyond 2007.”
“There is a significant opportunity for diesels in the global market,” Smyth says. “The question is can we create a market for North America post-2007 that the customer is prepared to buy?”
Cooled Ring Carrier Design For Direct Injection Diesel Pistons

The high ignition pressures, temperatures and specific output of the latest generation direct-injection diesel engines are creating new challenges for engine component suppliers. Emissions-compliant engines place new demands on components, especially those directly involved with the combustion process such as pistons, in the area of thermal loading.
Mahle Inc. has developed a line of aluminum pistons for high-speed light, medium-and heavy-duty, direct injection diesel engines that features a cooled ring carrier designed to be highly resistant to the increased temperatures of modern diesel engines.
The Mahle DI diesel piston is designed with a cooled ring carrier cooling duct formed by a steel plate. This sheet metal channel is welded directly to the ring carrier. Oil is circulated through the passage to assist in piston cooling. The design, Mahle says, is a departure from the more common salt core gallery cooled piston which has been used.
“The challenge is to design a piston and ring package that will be light, resist high combustion temperatures and pressures, control oil consumption and provide optimum sealing to prevent blow-by,” says Joe Strong, director of sales and application engines at Mahle.
The production of the cooled ring carrier Ni resist insert is accomplished by pressing a formed sheet metal channel onto the interior of the normal Ni resist material. One benefit of the welded steel design is the ability to place the cooling gallery closer to the top ring groove for better cooling of the piston crown and the top ring carrier.
According to Mahle, comparative finite element calculations on passenger car direct injection diesel pistons with cooled ring carriers and salt core cooling ducts have shown that the cooled ring carrier technology reduces the temperature at the bottom of the first groove by approximately 122 degrees F.
Phase Two of Peugeot/Ford PartnershipPSA Peugeot Citroen and Ford Motor Co. have unveiled new 1.6L and 2.10L common rail direct injection diesel engines for passenger car applications. The engines mark the second phase of the two companies’ cooperative agreement and will gradually equip both partners’ model lines in the second half of 2003.
The 1.6L HDi（PSA）/ Duratorq TDCi (Ford) has been derived form the 1.4L HDi（PSA）/ Duratorq TDCi unit that has to date been installed in nearly 400,000 cars.
Two versions of the 1.6L unit will be available. The main 110 hp engine offering 177 lbs.-ft. of torque at 1,750 rpm will be followed with a 90 hp unit with 156 lbs.-ft. of torque.
Seventy percent of maximum torque is available at 1,250 rpm thanks to the use of an intercooler Garrett variable geometry turbocharger (VGT), specifically developed for the engine. The 4-cyl., 16 valve engines feature a bore and stroke that has been increased by 1.3 mm and 6.3 mm respectively over the 1.4L parent unit, resulting in a displacement of 1.6L.
The 1.6L engine utilizes a Bosch second-generation fuel injection system. This system helps minimize emissions at the source with an increase maximum pressure of 1,600 bars, combined with small diameter injector nozzles featuring six 0.135 mm inlet ports. In addition, a wider injection spray angle is deployed in conjunction with an enlarged bowl in the combustion chamber.
The partnership claims the redesigned chamber enables the common rail system to realize the full potential of its multiple injection parameters. More powerful electronic control units combined with new more precise fuel injectors enable up to six injections per engine cycle. Two pilot injections to improve regeneration efficiency of the particle filter system.
The 2.0L HDi/ Duratorq TDCi is the latest development of the 2.0L family that has equipped PSA Peugeot Citroen mid-and upper-range cars since 1998. It use the architecture of the DW10 power plant, and is designed around a cast iron block with an 88 mm*85 mm bore and stroke topped with a 16-valve aluminum cylinder head.
Substantial efforts were made to reduce the edginess height and width to improve the integration of front-end design parameters and ensure better energy dissipation. By comparison with its predecessor, the new engine is 40 mm narrower and 15 to 20 mm shorter,
allowing both frontal impact and pedestrian impact design parameters to be met.
With a maximum power of 136hp at 4,000 rpm, the 2.0L HDi/ Duratorq TDCi is about 25 percent more powerful than its forerunner, yet offers the same fuel consumption. The new generation Siemens common rail direct injection system on the 2.0L engine features the multiple injection capability, with control of up to six injectors. Injection pressures of 1,600bar are controlled with piezoelectronic actuators. The cooling system has been fitted with an electronically controlled heat management unit that enables the system to reach maximum efficiency more quickly and reduce fuel consumption.
The 2.0L unit features a Garrett VGT turbocharger that aids the engine in achieving a maximum 251 lbs.ft. at 2000 rpm.
The engines will be manufactured at PSA Peugeot Citroen’s plant in Tremery, in the Moselle region of France where output of the 2.0L engine is scheduled to reach at least 2,300 units per day by 2002. Production of the 1.6L HDi/ Duratorq TDCi is expected to reach 1.1 million engines per year by 2005.

-Mike Mercer

[ 本帖最后由 sphynix 于 2007-4-11 20:07 编辑 ]

FreddyMusic

Looks like a news ?

What's your opinion about NOx and diesel engine ?

sphynix

Well,then there will be a lot we need to talk about it.
Today,most of the study on diesel engine is how to reduce NOx and particulates.For now,the most efficient way is using high-pressure common rail.I think disesel engine will be the direction,because the energy sources lack.

God,forgive my poor English.I do really want to say more about it.