Diesel vehicles

Automotive Emission Control Catalysts. Air pollution (qv) problems caused by automotive exhaust emissions have been met in part by automotive emission control catalysts (autocatalysts) containing PGMs. In the United States, all new cars have been requited to have autocatalyst systems since 1975. In 1995, systems were available for control of emissions from both petrol and diesel vehicles (see Exhaust control, automotive). 

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 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... 

Abstract The market of Diesel vehicles in Western Europe is, presently, still growing. In Asia, this market is still in an embryonic state (but should result as gigantic), while tomorrow the USA could become The Market . Diesel technology is an important issue for the carmakers, because it emits noticeably less Greenhouse gas than its gasoline counterpart. 

End of Abstract Nowadays, the Diesel vehicles market in Western Europe keeps growing. Diesel technology is of interest for car manufacturers because the Greenhouse gas emissions are noticeably lower with Diesel than with gasoline (do not forget the ACEA1 commitment for 2008 140 g/km of C02 for the new cars sold in European Union). A major issue for the Diesel vehicles is to clean-up HC, CO, NO and soot particles released by the engine at a minimum cost. 

Today, some institutes and organizations in charge of air quality analysis raise an alert, because the N02 level over the last years has remained quite unchanged while the NO level has significantly decreased. The spotlight is put on the Diesel vehicles because their DOCs in the exhaust line produce NOz by NO oxidation (nevertheless NO remains the major species emitted by the engine). 

The limited space available for the SCR system onboard of diesel vehicles had lead to the idea of using a special hydrolysis catalyst in front of the SCR catalyst [23,28]... 

Standard-SCR is also the basic reaction over SCR catalysts in diesel vehicles, as more than 90% of the NO in diesel exhaust is composed of NO under usual operation conditions. 

Hybrid and clean diesel vehicles may cost more than current internal combustion engine vehicles. But, their greater fuel efficiency means that they may make up that extra up-front cost over the lifetime of the vehicle. This means that hybrids and diesels may have roughly the same annual operating costs as current internal combustion engine vehicles. 

While fuel-efficient diesel vehicles represent roughly 50% of passenger cars in the EU (with a rapidly growing share), their shares in the USA are still less than 10%, and in China even more negligible with less than 5%. 

The risk of explosion or fire associated with the use of mobile telephones in a LPG vehicle is extremely low. First, LPG vehicle fuel systems are closed systems with safety features to prevent accidental release of LPG. The risk of fuel leakage is less than that of a petrol or diesel vehicle. Second, LPG will only bum when mixed with air in proportions within the flammable limits and when there is an ignition source. Working with higher-pressure fuel systems requires special tools and... 

Sara Smith Tim Caine (2007) studied lead concentrations in particulate matter in Pittsburgh. They wanted to see how much lead there was in the particulate and what the sources of the lead might be. They found about 65% of the lead was from diesel vehicles. About 20% was from emissions from nondiesel vehicles. The remaining 15% was from industrial emissions. The lead concentrations were reported to be somewhere between 2 and 20 parts per billion (ppb). 

The SCR technology is also considered for the control of NO emission in diesel vehicles. Here the SCR catalyst is typically placed after the diesel oxidation catalyst (DOC), which is used to oxidize CO and UHCs and to convert part of the NO to NO2. In this way, the SCR catalysts can take advantage of the fast SCR reaction to enhance significantly the de-NO efficiency at low temperature (Figure 13.4). The fast SCR reaction is based on the following stoichiometry ... 

Hammerle, R., D. Schuetzle, and W. Adams, A Perspective on the Potential Development of Environmentally Acceptable Light-Duty Diesel Vehicles, Environ. Health Perspect., 102, 25-30 (1994). 

M. Gautam, D. H. Ferguson, G. R. Neuroth, and K. D. Stevens, Characterization of Heavy-Duty Diesel Vehicle Emissions, Atmos. Environ., 28, 731-743 (1994). 

Miguel, A. H., T. W. Kirchstetter, R. A. Harley, and S. V. Hering, On-Road Emissions of Particulate Polycyclic Aromatic Hydrocarbons and Black Carbon from Gasoline and Diesel Vehicles, Environ. Sci. Technol., 32, 450-455 (1998). 

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