Catalytic converters are quite common for gasoline engines but diesel catalysts are less known, in part because they face greater challenges. Still, diesel catalysts have not disappeared because they are efficient and, when you start your car, they don't produce heaps of CO₂. Their main problem is the large amount of carbon particulates (soot) and nitrogen oxides in the exhaust gas. Standard three-way converters are not effective because of the high oxygen content of these gases. BASF is on the case, though. BASF's catalyst researcher Bob Farrauto said, "To solve this problem, we have developed special diesel oxidation catalysts combined with particulate filters which trap the soot and periodically oxidize it using a combination of catalysts and engine controls."

What about nitrogen oxides, which are the main source of acid rain? NOx storage devices or traps are incorporated into the catalyst to first store the nitrogen oxides which are then converted to nitrogen. The storage catalyst is regenerated afterwards. Alternatively an ammonia-carrying liquid (i.e. urea) can be injected into the exhaust and passed over a highly selective catalyst which converts the NOx into N₂.


[Source: BASF]

British Columbia-based NxtGen has recieved $5.5 million in funding from the Government of Canada, EnCana Corporation and Sustainable Development Technology Canada that will allow them to proceed with a field testing program of their diesel aftertreatment system. The system is designed to be either retrofitted to existing diesel engines or built into new models. The key is a syngas generator that uses exhaust gases and diesel fuel to produce a mixture of hydrogen and carbon monoxide. A lean NOx trap captures the nitrogen oxides in the exhaust stream and is regenerated using the syngas. The syngas reacts with the NOx to convert it to nitrogen and water. NxtGen claims the syngas can be used with a solid oxide fuel cell as an auxiliary power unit allowing the diesel engine to be shut down, reducing idling emissions and fuel consumption. NxtGen's system will be installed on twelve trucks in three different fleets across Canada for testing. If the system is proven effective it could be a viable alternative to urea injection systems for diesel engines.

[Source: NxtGen]

The City Council of Madrid, Spain, has unveiled plans to create a low-emissions zone in the city center which would ban polluting cars. This system is very similar to the ones implemented in several German cities and differs from Milan and London's option of an urban toll (or congestion charge).

If the measure gets the green light, only cars that accomplish the Euro III emission standards or higher would be allowed in the city center from 2010. Note that German cities require Euro IV and Diesel Particulate Filters for diesels. Residents might be exempted from this measure.

According to the City Council, this area will reduce NOx emissions by 47 percent, as well cutting particulate matter (under 10 micrometers) by 37 percent. Madrid's traffic accounts for more than 75 percent of NOx and particulate emissions in the city.

[Source: Europa Press via Econoticias]

Whether or not you believe in global warming, nitrogen-oxides, or NOx, definitely does contribute to acid rain and smog, which are not debatable. Because NOx is emitted in large quantities from the exhaust of diesel engines, something needs to stop it from entering our atmosphere. One way to do this is with urea, which is being used in the Bluetec systems installed by various automakers. Because people don't like to think about carrying around a container of urea (think urine, although it is usually created chemically, not gathered "naturally"), it is often referred to as Adblue, and because it is a source of ammonia, must be metered properly as ammonia is rather toxic by itself. Are there any other solutions?

The Chemical Engineering Division of Argonne National Laboratory in the U.S. has come up with a possible alternative to ammonia and urea. Their process uses Cu-ZSM-5, a zeolite with copper ions attached within its micropore structure, "with an external coating of cerium oxide", according to Christopher Marshall, who helped develop the technology. The technology also does not contain platinum, which is expensive and not compatible with the older diesel fuels which contained high amounts of sulphur.

This catalyst is currently under testing, but is proving to work out well enough that Argonne is expecting to have the product commercially available in as little as two years. I think it sounds pretty promising myself, because while I don't mind using urea at all, I think it is good that the consumer would not be left in charge of being sure that the Adblue tank was not empty.

[Source: Argonne National Laboratory]

Click on the image for a gallery of high-res images of the 2007 Mercedes-Benz E320 Bluetec.

Writing for the Los Angeles Times, Dan Neil has a good piece about the California Air Resources Board adopting the EPA's Tier II, Bin 5 emission standard two years before most of the U.S. leaving the 2007 Mercedes-Benz E320 Bluetec as out of reach for Californians. Neil points out that the new E320 Bluetec does meet the Bin 8 emissions standard and gets 45 percent(!) better fuel economy than the equivalent petrol-powered E350.

Bluetec of course is Mercedes-Benz's branding for their clean diesel technology which sees the E320 Bluetec equipped with a NOx adsorber-catalyst, exhaust gas recirculation and a particular filter. Like your average modern oil burner, the off-the-mark times and power ratings aren't all that noteworthy, but the torque is massive. Neil describes the E320's pull well, "[it] has torque like a nuclear attack sub."

As I described in my recent Volkswagen Passat TDI review, all that torque results in amazing overtaking ability, "Even while driving up a reasonable gradient doing 100 km/h with the engine ticking over at 1,500 revs in sixth, there is torque on tap to blow past other cars without the Direct Shift Gearbox (DSG) even needing to switch down if you bury your foot."

Neil describes a similar sensation in the E320, "In the passing lane, this inoffensive burgher of the interstate pulls like a BMW M3."

Analysis: The only problem with buying a huge saloon with a clean diesel engine and great fuel economy is that you probably should have bought a smaller car anyway. Switching to diesel vehicles to maintain an unsustainable love affair with big vehicles is false economy.



Click here to watch Neil eat an E320-toasted bagel.

Related:

• In the AutoblogGreen Garage: 2007 Volkswagen Passat TDI
• Green Car Journal names its favorite 2007 models
• Camry Hybrid named 2007 Canadian Car of the Year

[Source: LA Times]

Just days after we wrote about the problem of trying to introduce cleaner locomotives into existing railway's fleets, Union Pacific Railroad has unveiled the first of 60 new environmentally friendly, ultra-low emission diesel locomotives for use in the Los Angeles region.

In prototype and testing since 2002, the new locomotives are called "Generator-Set," or "Genset" switchers and are manufactured by National Railway Equipment Co. Each Genset locomotive is powered by three 700-horsepower, ultra-low emissions Environmental Protection Agency (EPA) non-road Tier 3-certified diesel engines. The move to this new ultra-low emissions technology is projected to reduce emissions of both particulate matter and NOx by up to 80 percent, while still managing to use up to 16 percent less fuel compared to current low-horsepower locomotives.

The 60 new locomotives will be delivered over the next six months for use in sorting rail cars for outbound trains. They will replace many of the 95 older locomotives currently being used in Los Angeles Basin rail yards.

Around half of Union Pacific's 8,500 plus locomotive fleet is certified under existing EPA Tier 0, Tier 1 or Tier 2 regulations governing air emissions. This means of course that a huge percentage of their fleet doesn't meet Tier 2 standards. Hopefully Union Pacific's testing of two different retrofit technologies for reducing emissions in older locomotives, an experimental "oxidation catalyst" filtering canister and a diesel particulate filter, will prove successful and see their existing locomotives upgraded to improve air quality.

The experimental oxidation catalyst is designed to be installed inside the diesel engine's exhaust manifold on a high-horsepower long-haul locomotive. The special catalytic material chemically reduces the amount of unburned hydrocarbons, carbon monoxide and particulate matter generated by the diesel engine, much like a catalytic converter on today's cars and trucks. The diesel particulate filter being tested is for use on low-horsepower yard locomotives.

Analysis: It is critical to improve the fuel economy and reduce the emissions of all forms of transport and it's great that Union Pacific is introducing new locomotives which meet new emissions regulations. Arguably more important though is retrofitting emissions reduction technologies to existing locomotives, many of which aren't scheduled to be entirely replaced for decades yet.

Related:

• Green train technology needed to keep air clean
• Union Pacific searching for cleaner locomotive breath

[Source: Union Pacific Railroad]

Industry organisation, Diesel Technology Forum, has announced that all major heavy-duty truck and engine manufacturers have met new Environmental Protection Agency standards for emissions cuts and have been certified by EPA for full production. To meet the new emissions requirements, new long-haul trucks are equipped with particulate matter filters which result in 2007 models being 90 percent cleaner than the previous generation. Nitrogen oxide (NOx) emissions have also been reduced significantly with new technology.

Manufacturers now certified by the EPA to meet the most stringent diesel emissions standards in the world include Caterpillar, Cummins, Detroit Diesel Corp., International, Mack and Volvo. With 94 percent of goods shipped via diesel trucks, the life-cycle emissions of any products will fall as new trucks replace aging rigs on the road. Once new trucks fully replace the existing fleet, EPA predictions put the reduction in emissions of smog-forming gases at 2.6 million tons each year, and soot emissions at 110,000 tons annually.

Analysis: With clean(er) diesel technology now on the market via new 2007 truck models, governments need to look at incentives to get old trucks off the road. All the hard work by the truck and engine manufacturers to meet the EPA rules won't amount to much if it takes thirty years to turn over the fleet.

Related:

• DaimlerChrysler's Dr. Z wants Americans to take a fresh look at diesel
• Dodge Ram first to meet strict 2010 diesel emissions standards
• Isuzu sticks with GM for DuraMax diesel engine joint-venture

[Source: Diesel Technology Forum]

General Motors has announced its Medium Duty Truck lineup for the 2007i (the i stands for interim) and 2008 model years feature increased performance, increased driver comfort and reduced diesel emissions. Included are an all-new Chevrolet and GMC W-Series, as well as revised diesel engines and exhaust systems to ensure GM medium-duty trucks meet new, more stringent federal and state of California diesel as emissions standards.

All models featuring diesel engines meet the new, 2007 Environmental Protection Agency (EPA) requirements for the reduction of nitrogen oxide (NOx) and particulate matter (PM) emissions by 90 percent over the previous (2004) diesel engine standards. NOx emissions have been reduced in the 5.2L, 6.6L and 7.8L diesel engines via an advanced exhaust gas recirculation (EGR) system and a variable geometry turbocharger.

Particulate matter has been reduced via a ceramic honeycomb channel diesel particulate filter (DPF) which captures sulfate particles and soot. Exhaust gases are directed through the channels and a porous material that traps the particulates. To clear the particulates and prevent clogging, a regeneration process occurs to burn off the trapped particulates and clean the filter using high exhaust gas temperatures.

To meet the EPA regulation for lower diesel fuel sulfur emissions, GM-designed emissions systems work efficiently with the new fuels and lubricants. The 2007 emission regulations also require all crankcase gas emissions to be reduced. To comply, a closed crankcase system was added to reroute ventilation gases back into the engine for combustion.

Analysis: A lot of work has gone into meeting the 2007 EPA diesel engine requirements by GM and all the diesel engine manufacturers. Their costs to comply with the clean air rules is our benefit as every new diesel vehicle that retires an old diesel vehicle will see the air become cleaner and cleaner. With the work done now to meet 2007 regs, GM and others can turn their research and development over to even more advanced green technology such as diesel-electric hybrids.

Read the complete press release after the jump.

Related:

• "EnviroFuels offers the first ever EPA-verified, patented technology that drastically reduces fuel costs and emissions with minimal capital costs"
• Wal-Mart orders diesel-electric hybrid truck prototype from ArvinMeritor
• First 2007 Caterpillar Engine with ACERT Technology begins production

[Source: GM]

Diesel Technology Forum has released a new PDF white paper designed to give diesel users a comprehensive overview of how diesel technology and regulations are changing to reduce diesel emissions. Covered are the new diesel emissions standards and the introduction of Ultra Low Sulphur Diesel (ULSD), as well as a number of techniques that can be used for upgrading existing diesel engines to reduce emissions.

Three interdependent components are discussed as the basis for a clean diesel system; the use of ULSD fuel which not only greatly reduces sulphur emissions but can also reduce particulate matter by up to 10 percent; new engine technology with redesigned combustion chambers, common rail fuel injection systems and variable geometry turbos that greatly reduces particulate matter and NOx emissions; and emissions control technologies including diesel oxidation catalysts, selective catalytic reduction devices, lean NOx catalysts, exhaust gas recirculation, and active diesel particulate filters. When combined, these three components usher in a new era of clean diesels which emit 98 percent less particulate matter and NOx in 2007 models than 1988 levels.

For existing diesel vehicle owners, the five Rs of retrofitting are also discussed; Rebuild core engine components every three to four years; Refuel using ULSD and/or biodiesel; Retrofit exhaust emissions control technologies; Repower older engines with new or newer diesel engines; and Replace entire old, heavily emitting vehicles and equipment with new models. Sections on Implementation Criteria for successful retrofitting projects, Incentives And Funding Resources, and Sample Retrofit Projects rounds out the paper.

Hopefully large diesel fleet owners will take heed of the advice offered in this white paper and look at implementing their own retrofitting projects to improve the emissions output of the dirtiest diesels on and off the road today.

Related:

• Biodiesel standard tests begin in Canada
• Onboard diagnostics promoted by EPA
• Is your diesel tank really getting ULSD fuel?

[Source: DieselNet]

SuperGen, a new electro-mechanical supercharger technology jointly developed by automotive engineering specialist Integral Powertrain and transmission technology company NexxtDrive, is designed to improve on existing turbo diesel theory. The variable-speed, electrically-controlled supercharger design uses an advanced gearing system that can accurately vary the speed of the turbo compressor from zero up to 150 times crank speed.

High powered, large turbos are inefficient at low speed when the exhaust gas flow rate falls. This leads to turbo lag and the tendency for drivers to hold the gearbox in a lower gear to keep the engine speed up, which in turn leads to higher emissions. The SuperGen system is designed to run alongside a conventional turbocharger, allowing its rapid acceleration to deliver boost at low engine speed for lag-free responsiveness. The turbo then takes over at higher revs as the SuperGen fades out.

Additional boost from the SuperGen system, which can be provided on demand regardless of engine speed, can be used to optimize Exhaust Gas Recirculation (ERG) performance for lowering NOx emissions. Exhaust Gas Recirculation adds exhaust gases to the cylinder which reduces oxygen availability. This in turn reduces the temperature of combustion resulting in the creation of nitrogen oxides being minimized. Conventional turbo technology has found it difficult to achieve peak performance with EGR, particularly where high peak power is required.

Related:

• 'Boost Hybrid' system one-third cost of regular hybrid powertrains

[Source: Autopresspoint]

In an annual report, the Environmental Protection Agency stated that smog levels have dramatically dropped for 19 Eastern states covering roughly 1/3 of the nation's population. The reduction is primarily due to fewer emissions of nitrogen oxides (NOx) from industrial plants and manufacturing facilities. According to the report, NOx emissions went from 1.2 million tons in 2000 to 530,000 tons in 2005. Other major sources of NOx are vehicle exhaust, gas vapors and chemical solvents.

In 1998, the Clinton administration implemented a market-style pollutant credit trading system for the 19 states which was expanded under the Bush administration. EPA administrator Stephen Johnson said that under the market system, the large, most problematic facilities were the first ones to install new pollution control equipment.

The dramatic results seen here for reduced levels of NOx are particularly promising for California's new bill that aims do the same for greenhouse gas emissions which employs a similar credit trading system.

Related:

• California to cap all greenhouse gas emissions

[Source: Associated Press via MSNBC]

Consumer Reports discovered the overall fuel mileage on a flex-fuel 2007 Tahoe went from 14 mpg on gasoline to 10 mpg on E85.

CR quoted an average price of E85 at $2.91 and said that drivers would essentially pay almost $4 for the equivalent gallon of gasoline. From a different angle: the Tahoe's driving range decreases from 440 miles on a tankful to 300 miles.

A review of the study on MarketWatch pointed to the political and environmental benefits of using E85.

Another story on the CR test at ConsumerAffairs.com noted that the highway mileage decreased from 21 to 15 mpg and the city driving dropped from 9 to 7 mpg. It said CR took the Tahoe to an emissions lab and found significant decreases in NOx while running E85.

Both stories cited benefits to the automakers in meeting CAFE requirements as one of the reasons for the current rush to build more flex-fuel vehicles.

[Source: MarketWatch]