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The Automotive Industry:

The Automotive Industry:. Fuel Value Chain Heavy Duty Diesel Technology. Section Overview. Air Pollutants from Diesel HDVs HDVs Engines Units European HDD Engine Standards Particulate Matter HDD Emissions Effect of Fuel Quality Heating Release and Cetane Sulfur Conclusions.

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The Automotive Industry:

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  1. The Automotive Industry: • Fuel Value ChainHeavy Duty Diesel Technology

  2. Section Overview • Air Pollutants from Diesel HDVs • HDVs Engines • Units • European HDD Engine Standards • Particulate Matter • HDD Emissions • Effect of Fuel Quality • Heating Release and Cetane • Sulfur • Conclusions

  3. Air Pollutants from Diesel HDVs • Pollutants similar to diesel light-duty vehicles • Carbon monoxide • Oxides of nitrogen (NOx) • Hydrocarbons (HC or THC) • Particulate Matter (PM) • Sometimes (NOx + HC) are regulated together • Carbon dioxide • Implies fuel efficiency Image Source: www.peterbilt.com

  4. Heavy Duty Diesel Engines • Fuel economy favors use in commerce • no throttling losses • emissions control impacts efficiency • Power density is now high • 35 kW/liter on-road Image Source: www.everytime.cummins.com

  5. Heavy Duty Diesel Engines – cont’d • Lower speed operation than for light duty • 1,800 rpm rated speed typical for large trucks • Rated speed is increasing to 2100 rpm. • Higher speed = higher power density • 2,600 rpm typical for 1-liter per cyl. engines • Higher fuel ignition tolerance • Stringent on-road standards • NOx (0.02g/hp-hr USA 2010), PM • PM traps (2007, USA on-road) Image Source: www.cat.com

  6. Units • Light-duty vehicles are usually regulated in distance-specific units, eg. g/mile or g/km. • Heavy-duty vehicles are regulated through engine emissions standards. Brake-specific (Brake = flywheel energy) units are used, such as g/bhp-hr or g/kw-h. • They can be compared approximately using fuel-specific units, such as g/kg fuel or g/gallon fuel. • The nature of the test cycle will affect emissions, regardless of units chosen

  7. European HDD Engine Standards • In 1992 Euro I standards were introduced. The NOx and PM levels are easily attained • Euro II regulations in 1996 and 1998 reduced NOx slightly and PM was reduced by more than a factor of two • Euro I and II used steady-state tests • Euro III standards (2000) introduced NOx and PM levels similar to US 1998 standards. These can be met with fairly conventional technology • Euro IV/V standards (2005/2008) included allowance for enhanced environmentally friendly vehicles • As in the US, off-cycle emissions are prohibited • There are durability requirements.

  8. PM • Particulate matter (PM) is usually defined by a filter collection method • Filter method implies a mass standard • Europe is adopting number count • Number count / mass / health effects research is ongoing (ACES) • PM consists of small particles and condensed droplets • Composition varies widely • PM is often classified by size • Both primary (tailpipe soot, brake dust) and secondary PM (from NOx) arise from engines and vehicles

  9. PM Emissions & Turbocharging • Turbochargers increase engine power density • Full boost • Wastegates • Variable geometry • Variable vane • There is a 1 to 4 second lag in boost • A “puff” of PM (and CO) arises if the engine is too rich during a transient images: Garrett turbocharger & www.dieselparticulatefilter.com

  10. HDD Emissions

  11. Meeting PM Standards – The Technology • US 1991 Standards or Euro II 1996 standards are reasonably easily met with high pressure fuel injection and careful air management • Euro III and US 1994 standards require more attention to air management. Electronic control is a benefit • Euro IV and US 2007 levels represent substantial reduction and require exhaust PM filtration • Catalyzed exhaust PM filtration requires “ultra low sulfur diesel” (10 to 50 ppm)

  12. Exhaust PM Filtration Technology Images: www.dieselforum.org

  13. Injection Styles for Diesel Engines • Common rail operation permits multiple injections (or rate shaping), high pressure injection, and precise control. • Unit Injectors are still widely employed • Both styles offer multiple injection opportunities • Fuel must have sufficient lubricity for all diesel engines (Europe: 460-microns wear scar maximum limit via HFRR test) (ASTM D975 Lubricity, HFRR @60°C D6079 520 max microns) Image Source: Bosch & Delphi

  14. Fuel Quality Effects

  15. Fuel Effects • Effects are similar for heavy-duty and light duty • High cetane & high paraffin fuels reduce NOx, improve cold starting • Ultra-low sulfur levels are required for oxidation catalysts and catalyzed PM filters • Control of T90 or T95 assists in reducing PM • Low-sulfur & low base lubricating oils are now favored for use with ULSD

  16. Relating Heat Release and Cetane • Low cetane causes large premix burn • Premix burn encourages NOx formation • Low cetane hinders starting Source: Dieselnet.com

  17. Diesel Sulfur Content • Europe • 1994 2,000 ppm. (49 Cetane) • 1996: 500 ppm. • 2000: 350 ppm (51 Cetane) • 2005: 50 ppm maximum. “Sulfur-free” 10 ppm sulfur diesel also required. • 2009: 10 ppm • USA • 2006: 15 ppm for on-highway, ready for 2007 low PM standard

  18. Conclusions • Fuel quality effects are similar for LDVs and HDVs • Sulfur content is the most important issue • T90/T95 limit is important to reduce PM

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