Diesel emissions standards

Figure 7.1. Diesel emissions standards from EuroII to EuroV on a four-axis space corresponding to the pollutants soot particles, HC, NO and CO.

NOx and NMHC standards will be phased in for diesel engines between 2007 and 2010. In Japan, diesel emission standards require that in-use, on-road, light commercial vehicles in the specified categories should meet NO emissions of 0.25 g/km starting from the end of 2005 and achieve full implementation by 2011. Also, Table... 

Table lU.S. Heavy/Medium Duty Diesel Emissions Standards (HD U.S. Transient Test Cycle)... 

Dollmeyer T A, Vittorio D A, Grana T A, Katzenmeyer J R, Charlton S J (2007) Meeting the US 2007 Heavy-Duty Diesel Emission Standards - Designing for the Customer. SAE Technical Paper 2007-01-4170... 

Table 21.2 California diesel emission standards for 8,500-14,000 lbs. (Chassis certified at 120,000 mi, all emissions in g/mi)...

The benefits of alcohol fuels include increased energy diversification in the transportation sector, accompanied by some energy security and balance of payments benefits, and potential air quaUty improvements as a result of the reduced emissions of photochemically reactive products (see Air POLLUTION). The Clean Air Act of 1990 and emission standards set out by the State of California may serve to encourage the substantial use of alcohol fuels, unless gasoline and diesel technologies can be developed that offer comparable advantages. 

Effective with the 1982 model year, particulate matter from diesel vehicles was regulated by the U.S. Environmental Protection Agency for the first time, at a level of 0.37 gm km . Diesel vehicles were allowed to meet an NO level of 0.93 gm km under an Environmental Protection Agency waiver. These standards were met by a combination of control systems, primarily exhaust gas recirculation and improvements in the combustion process. For the 1985 model year, the standards decreased to 0.12 gm of particulate matter per kilometer and 0.62 gm of NO per kilometer. This required the use of much more extensive control systems (1). The Clean Air Act Amendments of 1990 (2) have kept the emission standards at the 1985 model level with one exception diesel-fueled heavy trucks shall be required to meet an NO standard of 4.0 gm per brake horsepower hour. 

The main pollutants in Diesel exhausts are NOx and particulate matter (PM), mostly soot, with lesser amounts of CO and light hydrocarbons (CH). Table 12.1 shows the corresponding emission standards in Europe and in the USA. These standards are becoming progressively stricter and Table 12.2 shows the needed conversion efficiency of the electrochemically promoted unit in order to meet the EUR04 2005 standards. 

The Emission Standard for New Diesel Vehicles, issued in December 1988, established a maximum of 50 Hartridge Opacity Units. The Ecological Technical Standard of June, 1988, enforced the maximum allowable emissions for circulating cars (Table IV). The Diesel Regulation... 

Understanding particulate emissions, their formation and control, is another key issue in meeting the new particulate emission Hmits set by the new EURO emission standards. The particulate emissions formed in diesel engines have a mass median diameter of 0.05-1.0 gm. Particle consists of carbon with various HCs adsorbed on it including polyaromatic hydrocarbon (PAH) as well as nitro-PAH compounds. 

In summary, the NOx mass to convert (difference between engine-out NOx emissions and NOx emissions limit imposed by Diesel Euro standards) governs the requested duration for the rich conditions in the exhaust line (NOx regeneration duration), and thus dictates directly the quantity of methane released in the exhaust line. 

The CH4 emissions can reach significant values and even lead directly to a cleanup unfeasibility in certain cases, since these amounts can be close to the unburnt HC threshold imposed by Diesel Euro standards. However, even if the CH4 values do not reach the unburnt HC limit, these emissions are added in the vehicle exhaust gas and limit the global unburnt HC that the engine can release in lean conditions. Thus, with the NOxTrap, a new constraint is appearing, which will have an impact on the engine-out HC emissions during the lean conditions. As NOx emissions levels increase, CH4 emissions in rich mode increase, and it is then necessary to reduce HC emissions in lean mode to stay within the limits of the DOC conversion ability. This context is specific to... 

EPA-Diesel RIA, Regulatory Impact Analysis—Control of Air Pollution from New Motor Vehicles Tier 2 Motor Vehicle Emissions Standards and Gasoline Sulfur Control Requirements United States Environmental Protection Agency, Air and Radiation EPA420-R, 99-023. 1999. December. 

Emission standards, 21 584-585 diesel engine, 10 60 12 429—430 for new municipal waste combustors,... 

Diesels are less than 1% of car and light truck sales in the U.S. But, they are more popular in Europe with its high gasoline prices. Their fuel taxes help to promote diesels and the emissions standards are less strict. Diesels are in almost 40% of the cars in Europe. By 2001 they were in most of the new cars sold in many European countries. 

The toxic emissions with CNG, without exception, are lower than for any other hydrocarbon fuel. This is a direct result of the fact that CNG is a single hydrocarbon, 90% methane, whereas all of the other fuels are a mix of hydrocarbons. LPG is a relatively simple mix of propane, butane, and pentane compared to CNG and the complex mix that makes up the gasoline and diesel typically pnrchased at the service station. Gasoline and diesel emit compounds into the air methanol, formaldehyde, aldehydes, acrolein, benzene, toluene, xylene, etc., some of which ate not yet part of any established emission standard but certainly are not beneficial to people s health (Demiibas, 2002). 

Tables 13.2 and 13.3 show the European emission standards for passenger cars and for heavy-duty diesel engines.

Table 13.3 EU emission standards for heavy-duty diesel engines (gkw- h- ) (smoke in m ).

The ammonia SCR for heavy-duty diesel engines has been commercialized by Daimler since 2005 in Europe and the USA under the trade name Bluetec as an after-treatment system able to satisfy the Euro IV and Euro V emission standards. 

The new specifications not only limit the concentration of sulfur to 0.05% but also specify that the fuel should have the combustion properties of a 10% or lower aromatics-containing fuel and have a minimum cetane number of 40. Fuels that have more than 10% aromatics are now able to meet these specifications through additives (22). However, as smoke emission standards become more restrictive, the aromatics content of diesel fuels may have to be lowered to a true value of 10% or less. A very thorough review of the consequences of this potential problem has recently been written by Stanislaus and Cooper, which covers in detail aromatic hydrocarbon hydroprocessing kinetics, thermodynamics, catalyst compositions, and mechanisms (109). There is little need to repeat the details of that report... 

Emission standards With reference to Table 7.3 and Table 7.4 US emission (cars, diesel) exhaust standards calculate percentage of progress (a) for present requirements for 1992 cars and diesel, and (b) compare requirements for cars and diesel for HC, CO and NOx. 

Service category CG-4 designated to meet 1995 exhaust emission standards for use in high speed four-stroke-cycle diesel engines New classification for the generation of heavy-duty engine oils. The process of adsorption characterized by a chemical reaction between the adsorbate and adsorbent, where exchange of orbital electrons occurs. 

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