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Conference report: 10th FAD Conference

30 November 2012

The 10th FAD Conference was held on November 7-8, 2012 in Dresden, Germany. The conference is organized by the Research Association for Diesel Emission Control Technologies (Forderkreis Abgasnachbehandlungstechnologien fur Dieselmotoren, FAD)—an industry/academia group to promote science and research in the field of diesel aftertreatment technologies. The meeting was attended by about 250 delegates who discussed the latest trends in diesel emission control technologies.

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Light-Duty Engines. The technical program opened with a presentation by R. Dorenkamp (VW) who discussed the new modular vehicle and engine program by Volkswagen. The “modular transverse matrix” (MQB) vehicle platform is a new, modular vehicle architecture for transverse, front-engined and front wheel drive vehicles. The MQB platform, first used in the new Audi A3 and the VW Golf VII, comes with a number of standardized features, including standardization of the engine position for different types of powertrains (gasoline, diesel, NG, electric). The new, modular diesel engine (MDB) features a number of improvements with focus on fuel economy and CO2 emissions. The highlights include a 15% reduction in piston friction, balanced shaft module integrated into the crankcase, friction-reduced balance shaft system, oil/vacuum pump designed as a dual pump, and oil pump with controlled volume flow. The cylinder head, only 105 mm high, includes an integrated valve drive module. Dual loop (high + low pressure) EGR system is used with shortened EGR path for low pressure drop. The completely revised thermal management system utilizes separate cooling circuits for different cooling functions (engine coolant, charge air, EGR). An exhaust gas temperature of 150 C can be achieved in just 150 s over the NEDC test, minimizing cold start emissions. The aftertreatment system in the Euro 5 version includes a close-coupled DOC+DPF unit. The DOC volume has been significantly enlarged to accommodate the requirements of aftertreatment devices (such as NOx adsorbers) for meeting Euro 6 emissions. Fuel consumption of the 2 liter, 110 kW version is 4.1 l/100 km and CO2 emissions 99 g/100 km (VW Golf, NEDC test). Higher performance versions of the engine are to be developed in the future.

SCR Technology. Urea-SCR technology, well-established in heavy-duty diesel engines, is entering light-duty vehicle applications, including lighter, compact class passenger cars (J. Op de Beeck, Inergy). The adoption of SCR in European light-duty vehicle applications is driven by the existing CO2 regulations in combination with a number of future regulatory factors: (1) Requirements of the Euro 6c stage (2017/18) include more stringent OBD limits for NOx and PM; (2) The WLTP cycle that will replace the NEDC test is more dynamic and is expected to include cold start and operation with air conditioning; (3) Real driving emission (RDE) testing requirements will be likely adopted that include off-cycle and/or in-use PEMS testing. These increased demands on NOx control under all driving conditions will also result in increased urea consumption, with a today’s vehicle that consumes about 1 l/1000 km of urea expected to require up to 1.5 l/1000 km in the future. As a result, the average lifetime use of urea (AdBlue) by a passenger car is predicted to increase from 250 l to 360 l. This will put new requirements on urea pumps, tanks, and other components of the dosing system. Urea refill (performed today by the service station during regular vehicle service) may be required by the vehicle driver. This, however, would require a new urea distribution network for light-duty vehicles.

Diesel Particulate Filters. Rhodia (V. Harle) discussed the benefits of low levels of Fe fuel additive for the regeneration of catalyzed soot filters. Iron concentrations in the fuel on the order of 2-5 ppm could lower the filter regeneration temperature and improve the kinetics of soot oxidation, making the DPF system more reliable during low temperature operation such as in prolonged city driving. A new additive storage system, E-SIS, was proposed that is greatly simplified compared to the additive dosers that have been used in commercial additive-based DPF systems. Instead of storing the additive in a container incorporated into the fuel tank, in the E-SIS doser a disposable additive cartridge is integrated into the fuel filter. Each time the fuel filter is serviced, the E-SIS system is fitted with a new quantity of additive. A venturi nozzle is used for dosing the additive into fuel and no connection of the doser with the engine controller is necessary. While this ‘passive dosing’ method results in a gradual build-up of the additive concentration in the fuel followed by a rapid dilution during next fuel fill-up, the system was shown to be effective under real driving conditions. An ‘active dosing’ strategy is also possible, but it requires more complex hardware with a solenoid valve incorporated into the additive doser.

Other Topics. SP3H (E. Hermitte) evaluated their onboard NIR (near infrared) fuel quality sensor in an experimental study where a number of fuels of different properties (Swedish MK1, EN590, US low cetane, Mercosur) and biodiesel blends were tested in a single cylinder research engine. The NIR sensor can provide information on the chemical makeup of the fuel (e.g., the presence of various functional groups) and an estimation of FAME percentage. The NIR technology utilizes absorbency spectrum of the fuel sample in the 800-2440 nm wave length range. The sensor utilizes low cost solid state components, but it requires complex data processing. A large variability of emissions and engine performance was measured with the tested fuel matrix. The authors concluded that the feedback from their sensor could provide more flexibility in controlling the engine to achieve similar emission levels with each fuel than other available control feedback options, such as cylinder pressure and oxygen sensors.

The 11th FAD Conference will be held in Dresden on November 6-7, 2013.

Conference website: www.fad-diesel.de/conference-2012