xcel
01-26-2007, 02:01 AM
The second phase of BlueTec, with the AdBlue system, will arrive in late 2008. (http://www.sae.org/automag/techbriefs/01-2007/1-115-1-14.pdf)
http://www.cleanmpg.com/photos/data/552/Resize_of_MB_320_CDI.jpgDan Carney - SAE Tech Briefs - Jan. 2007
2007 MB 320 CDI BlueTec has an official fuel range of more than 600 mi (970 km), but in a test the cars went more than 1000 mi (1600 km) on a tank, traveling from Laredo, TX, to Tallahassee, FL.
DaimlerChrysler is rolling out the first of the new generation of clean diesels certified to meet the tough new federal Tier II Bin 8 emissions regulations for model year 2007. The new regulations require diesels to have the same very clean exhaust as gasoline-powered light vehicles. The diesels employ the Mercedes-Benz BlueTec technology, which is modular and can be improved in stages. A later phase of the technology involves injecting liquid urea-called AdBlue by Mercedes marketers-into the exhaust stream to help catalyze nitrogen oxides into nitrogen and water.
The first stage of the technology features a new, all-aluminum DOHC 3.0-L V6 (72° vee) engine dressed with the expected common-rail fuel-injection system and variable-geometry turbocharger. The 72° angle was selected to leave space in the engine’s valley for the turbocharger, explained Joachim Schommers, Director of Passenger Car Diesel Engine Development for Mercedes.
Vanes in the Honeywell variable-geometry turbocharger are made of a more heat-resistant alloy to better withstand the hotter exhaust gases that result from the exhaust valves staying closed longer to maximize the energy from each stroke of the piston. The nozzle design is more advanced, and airflow through the compressor has been optimized, Schommers said.
A higher-pressure, 1600-bar (23,200-psi) common-rail injection system and what Schommers describes as “third-generation” injectors complete the intake tract.
The engine has a slightly reduced 16.5:1 compression ratio to reduce production of nitrogen oxides that result from high compression. The reduction in compression ratio has very little effect on power output, said Schommers.
The engine’s architecture is undersquare, with a reduced bore and increased stroke compared to the old I6 powerplant. To reduce internal friction, the engine employs a roller rocker arm valvetrain, and bearing journal size has been minimized.
The debut of BlueTec in the U.S. was delayed by limited access to low-sulfur diesel fuel, which is needed to avoid fouling the oxidation catalytic converter. A particulate trap further scrubs the BlueTec’s emissions to the level of clean gasoline engines.
The V6 diesel engine in the Mercedes E320 BlueTec luxury sedan produces 208 hp (155 kW) and 400 lb•ft (540 N•m), resulting in 0-60 mph (0-97 km/h) acceleration of 6.6 s. The engine is also used in the 2007 Jeep Grand Cherokee as a new diesel option. The engine’s redline of 4600 rpm is lower than a similar gasoline engine because the compression-ignition combustion sequence takes longer than that in a spark-ignition engine, limiting maximum revs, Schommers said.
On the move, the engine does very little to betray that it is a diesel, though at idle that fact becomes apparent. Inside the cabin, with the windows closed, it would be easy to miss the sound of diesel clatter, but with the windows open the idling E320’s sound is apparent. It is not intrusive, however, and during regular driving the clatter disappears entirely.
The second phase of BlueTec, with the AdBlue system, will arrive in late 2008, with diesel power for the Mercedes ML-, GL-, and R-Class SUVs. The aftertreatment system will include a selective reduction catalyst that converts ammonia from the AdBlue and nitrogen oxides from the engine to create nitrogen and water.
The GL320 BlueTec will package its AdBlue reservoir under the rear cargo floor, where it will carry enough fluid to last between oil-change intervals. The system consumes urea at the rate of 0.1 L per 100 km (0.1 qt per 620 mi).
Replenishment of AdBlue by owners has been an obstacle to the system’s use in the U.S. Manufacturers have been reluctant to strand owners by not allowing the car to start when the reservoir runs dry, while the U.S. EPA refuses to allow careless owners to drive around indefinitely generating excessive pollution.
“We will inform the driver early,” said Schommers. “The notice comes more and more often, so he knows exactly when it won’t start.” During the warning period, the reservoir can be refilled at Mercedes dealers, and the company is in discussions with oil-change providers to supply AdBlue. Mercedes will maintain a telephone hotline to direct owners to the nearest source of AdBlue.
Filling the AdBlue reservoir with something else, such as water, might trick the system into letting the engine restart once. However, once the engine is running, sensors in the exhaust will detect that pollution levels are too high, and the engine will refuse to restart.
Mercedes investigated the possibility of producing ammonia on board from gasoline, but found that this is not an efficient solution, said Schommers. “The amount of ammonia you get is very low, and the amount of energy you consume is very high,” he said. The energy use is enough to have a noticeable impact on fuel economy, he added.
http://www.cleanmpg.com/photos/data/552/Resize_of_MB_320_CDI.jpgDan Carney - SAE Tech Briefs - Jan. 2007
2007 MB 320 CDI BlueTec has an official fuel range of more than 600 mi (970 km), but in a test the cars went more than 1000 mi (1600 km) on a tank, traveling from Laredo, TX, to Tallahassee, FL.
DaimlerChrysler is rolling out the first of the new generation of clean diesels certified to meet the tough new federal Tier II Bin 8 emissions regulations for model year 2007. The new regulations require diesels to have the same very clean exhaust as gasoline-powered light vehicles. The diesels employ the Mercedes-Benz BlueTec technology, which is modular and can be improved in stages. A later phase of the technology involves injecting liquid urea-called AdBlue by Mercedes marketers-into the exhaust stream to help catalyze nitrogen oxides into nitrogen and water.
The first stage of the technology features a new, all-aluminum DOHC 3.0-L V6 (72° vee) engine dressed with the expected common-rail fuel-injection system and variable-geometry turbocharger. The 72° angle was selected to leave space in the engine’s valley for the turbocharger, explained Joachim Schommers, Director of Passenger Car Diesel Engine Development for Mercedes.
Vanes in the Honeywell variable-geometry turbocharger are made of a more heat-resistant alloy to better withstand the hotter exhaust gases that result from the exhaust valves staying closed longer to maximize the energy from each stroke of the piston. The nozzle design is more advanced, and airflow through the compressor has been optimized, Schommers said.
A higher-pressure, 1600-bar (23,200-psi) common-rail injection system and what Schommers describes as “third-generation” injectors complete the intake tract.
The engine has a slightly reduced 16.5:1 compression ratio to reduce production of nitrogen oxides that result from high compression. The reduction in compression ratio has very little effect on power output, said Schommers.
The engine’s architecture is undersquare, with a reduced bore and increased stroke compared to the old I6 powerplant. To reduce internal friction, the engine employs a roller rocker arm valvetrain, and bearing journal size has been minimized.
The debut of BlueTec in the U.S. was delayed by limited access to low-sulfur diesel fuel, which is needed to avoid fouling the oxidation catalytic converter. A particulate trap further scrubs the BlueTec’s emissions to the level of clean gasoline engines.
The V6 diesel engine in the Mercedes E320 BlueTec luxury sedan produces 208 hp (155 kW) and 400 lb•ft (540 N•m), resulting in 0-60 mph (0-97 km/h) acceleration of 6.6 s. The engine is also used in the 2007 Jeep Grand Cherokee as a new diesel option. The engine’s redline of 4600 rpm is lower than a similar gasoline engine because the compression-ignition combustion sequence takes longer than that in a spark-ignition engine, limiting maximum revs, Schommers said.
On the move, the engine does very little to betray that it is a diesel, though at idle that fact becomes apparent. Inside the cabin, with the windows closed, it would be easy to miss the sound of diesel clatter, but with the windows open the idling E320’s sound is apparent. It is not intrusive, however, and during regular driving the clatter disappears entirely.
The second phase of BlueTec, with the AdBlue system, will arrive in late 2008, with diesel power for the Mercedes ML-, GL-, and R-Class SUVs. The aftertreatment system will include a selective reduction catalyst that converts ammonia from the AdBlue and nitrogen oxides from the engine to create nitrogen and water.
The GL320 BlueTec will package its AdBlue reservoir under the rear cargo floor, where it will carry enough fluid to last between oil-change intervals. The system consumes urea at the rate of 0.1 L per 100 km (0.1 qt per 620 mi).
Replenishment of AdBlue by owners has been an obstacle to the system’s use in the U.S. Manufacturers have been reluctant to strand owners by not allowing the car to start when the reservoir runs dry, while the U.S. EPA refuses to allow careless owners to drive around indefinitely generating excessive pollution.
“We will inform the driver early,” said Schommers. “The notice comes more and more often, so he knows exactly when it won’t start.” During the warning period, the reservoir can be refilled at Mercedes dealers, and the company is in discussions with oil-change providers to supply AdBlue. Mercedes will maintain a telephone hotline to direct owners to the nearest source of AdBlue.
Filling the AdBlue reservoir with something else, such as water, might trick the system into letting the engine restart once. However, once the engine is running, sensors in the exhaust will detect that pollution levels are too high, and the engine will refuse to restart.
Mercedes investigated the possibility of producing ammonia on board from gasoline, but found that this is not an efficient solution, said Schommers. “The amount of ammonia you get is very low, and the amount of energy you consume is very high,” he said. The energy use is enough to have a noticeable impact on fuel economy, he added.