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Bosch makes a status on Diesel engines impact on environment


Bosch explains why diesel is crucial to achieving CO2 targets, how to reduce nitrogen oxide emissions, and what impact smokers and tires have on emissions of particulate matter.

Paris, London, Stuttgart – air quality is at the focus of debate all over Europe – a debate that often centers on diesel engines. “In Bosch’s view, it’s important to base the air quality debate on facts,” says Dr. Rolf Bulander, chairman of the Mobility Solutions business sector.

CO2 reduction with diesel engines

“Diesel engines have never been more important than they are today. This technology is key to achieving fleet CO2 emission targets – in Europe especially, it is indispensable to that goal,” says Dr. Rolf Bulander, chairman of the Mobility Solutions business sector.

Share: Diesel cars generate some 4 percent of all CO2 emissions in Germany.

CO2 targets: Starting in 2021, the average new car in the EU will have an emissions cap of 95 g of CO2 per kilometer. In other regions too, such as the U.S. and China, vehicles have to become much more economical over the next few years.

Electrification: Electrification will give diesel engines another boost – particularly for large and heavy vehicles such as SUVs. Bosch offers several solutions, such as a 48-volt entry-level hybrid that can cut CO2 emissions in real-life driving situations by up to 15 percent.

Particulates filtering

”Thanks to today’s filters, diesel engines no longer have a problem with particulates,” says Dr. Michael Krüger, who heads up diesel technology development at Robert Bosch GmbH.

Share: According to official estimates, about 1 percent of all the particulate matter emitted in Germany is caused by exhaust emissions from cars.
Source: German Federal Environment Agency (Umweltbundesamt, UBA), national trend tables for atmospheric emissions, 2012

Particulate emissions in Germany

Efficient: Since Euro 1 was introduced in 1992, vehicle particulate emissions have been reduced by some 97 percent. The latest filters work at over 95 percent efficiency, and can filter out the smallest of nanoparticles.

Vacuuming: Measurements in major cities have indicated that today’s diesel engines even filter out particulates from the ambient air. For example, in the Parisian suburb of La Garenne, emissions from a diesel engine contain fewer particulates than the air that the engine takes in.
Source: Bosch in-house measurements

Dust: The wear and tear that driving puts on tires and brakes also produces particulates. On Germany’s roads, this already accounts for three times the particulate emissions of exhaust gas.
Source: ”Emissionen und Maßnahmenanalyse Feinstaub 2000-2020,” Umweltbundesamt (UBA), Germany (2007); ISSN 1862-4804

Cigarette smoke: Estimates suggest that in 2015, as many particulates will be produced by smoking as by automotive emissions.
Source: ”Emissionen und Maßnahmenanalyse Feinstaub 2000-2020,” Umweltbundesamt (UBA), Germany (2007); ISSN 1862-4804

Nitrogen oxide – attention turns to real driving emissions

“In the future, IC engines and especially diesel engines will have to be clean – even during rapid acceleration and at high speeds,” says Dr. Rolf Bulander, chairman of the Mobility Solutions business sector of Robert Bosch GmbH.

Share: Measurements have indicated that diesel cars are responsible for some 10 percent of NOx emissions in Germany. Aside from road traffic, other sources include energy generation (27 percent) and private households (11 percent).
Source: German Federal Environment Agency (Umweltbundesamt, UBA), national trend tables for atmospheric emissions, 2012

Nitrogen oxide emissions in Germany

Major advances: The EU introduced the Euro 3 norm in 2000. Since then, nitrogen oxide emissions from diesel cars have been cut by 84 percent in the relevant test cycle.

Euro 6: A directive of the European Union, this new emission standard primarily sets lower maximum values for vehicle emissions of particulates and nitrogen oxide. For diesel engines, the old standard stipulated a maximum of 180 mg per kilometer. As of September 1, 2015, diesel engines will be restricted to just 80 mg of nitrogen oxide emissions per kilometer (gasoline engines: 60 mg per kilometer).

A systematic approach to engineering: In order to improve the modern diesel still further, Bosch is drawing on a systems approach that combines internal combustion with exhaust-gas treatment. One of the vital technologies in this regard is Denoxtronic SCR, which can reduce nitrogen oxides by up to 95 percent in real driving situations. In this way, the limit of 80 mg of nitrogen oxides per kilometer can also be achieved in a number of real driving situations. On some journeys, emissions may be even lower than this limit.

AdBlue: Systems such as Bosch’s Denoxtronic inject odorless liquid urea, known as AdBlue, into the exhaust gas flow. This reacts with the exhaust gas and turns nitrogen oxide into harmless steam and nitrogen.

Real driving emissions: A number of vehicles currently in production already produce only a minimum amount of emissions, and do so even outside the applicable certification cycle – for example, during rapid acceleration or at high speeds. The task now is to drive the spread of this capability and develop cost-effective technologies that will ensure compliance, whatever the driving conditions.

Innovation: Bosch’s 48-volt boost recuperation system can reduce untreated nitrogen oxide emissions by up to 20 percent, especially at high loads or when the car is accelerating. Bosch believes the system could allow the storage catalytic converter to reduce nitrogen oxide emissions by up to 80 percent. Electrification will also increase the level of efficiency of urea-based systems (SCR catalytic converters).

Source: Bosch

Romain’s opinion:
I guess that the real problem with diesel engines within the city is not regarding Euro6 engines but rather regarding old diesel engines. Instead of promoting either diesel or gasoline or hybrid or electric vehicles, governments or car-makers should provide more incentives for buying new cars in general and trashing the old ones. Anyway, do you think that it will be asked to further reduce the pollutant emissions in Euro7 standard?

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