BMW EfficientDynamics: รายละเอียดของกระบวนการวัดค่าอัตราการสิ้นเปลืองเชื้อเพลิงและอัตราการปล่อย CO2 รวมทั้งข้อมูลเกี่ยวกับเทคโนโลยีเครื่องยนต์ดีเซล

The EU and many other countries around the world have undertaken to significantly reduce the greenhouse gas CO2. The diesel engine plays an important role in achieving this climate target: after all, diesel vehicles can present a good CO2 footprint on the basis of their lower consumption. A diesel that complies with the Euro 6 EU standard, for example, produces about 15% less CO2 than a comparable model with a petrol engine. Against this background, diesel cars in Europe have saved approximately 1,000,000,000 tonnes of CO2 in the last 20 years. And thanks to particle filters, which have been installed as standard at BMW since 2006, the proportion of diesel vehicles contributing to engine-related particulate emissions is practically no longer relevant.

Particulate matter is the term used for all the solids distributed in the air. Natural sources are erosion, fine dusts, volcanic eruptions and also pollen. In addition to road traffic, sources caused by humans include air and shipping traffic as well as industry. Roughly 20% of the particulate matter that occurs is due to cars, less from exhaust emissions than from tyre abrasion and turbulence. Thanks to the particle filters that have been installed within the BMW Group since 2006, our vehicles have almost no more particulate emissions generated by the engines.

Carbon dioxide is a greenhouse gas that is generated, for example, by the combustion of coal, diesel, petrol natural gas and wood. It plays an important role in nature for the metabolism of many living organisms and plants. I In excess, CO2 makes an important contribution to the greenhouse effect and hence to climate change. Within the EU, traffic is responsible for just under 30% of the entire CO2 emissions, with road traffic accounting for 72%. Without the diesel, which emits less CO2 than a petrol engine due to its low consumption, CO2 values would be significantly higher.

NOx is the collective name for nitrogen oxides, the gaseous oxides of nitrogen (N). Too high NOx concentrations put a strain on the lungs and can harm plants. Nitrogen oxides occur in the high-temperature combustion of fuels but also of coal, oil, wood and waste. Between 1990 and 2017, NOx emissions due to road traffic have decreased by more than 60%. As a result, the proportion of total NOx emissions due to road traffic in 2017 amounted to approx. 37.5%. BMW relies on a multi-stage procedure for reducing nitrogen oxides, which today is recognised as being extremely effective. Alongside emissions reduction in the engine and exhaust gas recycling, this particular includes exhaust gas after-treatment by a combination of NSC (Nitrogen Oxide Storage Catalytic Converter) and SCR system (Selective Catalytic Reduction). Interacting with the exhaust gas temperature and the AdBlue injection, the SCR system converts the toxic nitrogen oxides into the non-toxic components of water and nitrogen.
In the new 6-cylinder diesel engine from BMW, the previous very efficient exhaust gas after-treatment system consisting of a NOx storage catalytic converter, DPF (diesel particle filter) and underbody SCR is replaced by a system with an even higher functional potential. Here an SCR system (based on DPF) close to the engine works with an underbody SCR system in order to cover a very broad range of engine operations with optimal NOx conversion. This is also the basis for future exhaust gas standards.

The EU exhaust gas standard lays down the threshold limit values for emissions according to vehicle type and engine. Every year, new vehicles have to comply with more stringent exhaust gas regulations in order to obtain approval. Whether with diesel or petrol engine, all current new vehicles from the BMW Group comply with the Euro 6 exhaust gas standard. You will find the emissions class of your vehicle relevant for EU type approval in section V9 of the type approval certificate.

In order to meet EU emission limits in heavily polluted cities and to improve air quality in the long term, some European cities have environmental or low-emission zones with restrictions on traffic. According to the specific country, vehicles may only enter these zones under certain conditions, such as by displaying emissions stickers or complying with certain emission classes. Whether with diesel or petrol engine, the current new vehicles of the BMW Group comply with the Euro 6 emissions standard and are thus have approval for the majority of European environmental zones.

The emissions sticker supplies information on a vehicle’s EU emissions class. It is required in some European cities, such as Berlin for example, in order to drive into environmental zones with reduced emissions. At present, vehicles receive a red, yellow or green emissions sticker or no sticker at all according to the level of pollutants emitted. The current new vehicles from the BMW Group always comply with the Euro 6 emissions standard and thus receive the green emissions sticker on registration. This entitles you to drive your new BMW in most of the environmental zones in Europe.

The abbreviation WLTP stands for “Worldwide Harmonized Light Vehicles Test Procedure”.
This involves a new test procedure for a more realistic determination of fuel consumption and CO2 emission values of vehicles that will be legally binding for all vehicles as of September 2018. WLTP will replace the previously applicable NEDC procedure.

A vehicle’s consumption and emissions depend on driving style among other factors. This is why driving data have been compiled for WLTP around the world. These data were used to define 4 representative phases with different average speeds: low, medium, high and extra-high. Within each of these phases, there are different intensities of acceleration, braking and stopping in order to depict situations with a relevance to everyday driving style. The combination of these phases then results in the driving cycle which is communicated as a combined value in the manufacturer’s details. As electric and hybrid vehicles are used particularly within urban areas, their driving cycle contains a 5th phase: the City phase. This results from the average speeds of low and medium.

Introduction of WLTP will mean that the fuel consumption and CO2 values indicated will approximate those in real-world operation. Irrespective of this, taking into account individual special equipment in WLTP will additionally lead to more realistic values as they are based on your personal vehicle configuration. At the same time, however, more realistic values will also mean higher consumption and CO2 standard values for vehicles with combustion engines and a lower range for electric vehicles and plug-in hybrids. Depending on national legislation, higher CO2 taxes may result.

The abbreviation RDE stands for "Real Driving Emissions". This is a new procedure for determining pollutants such as nitrogen oxides (NOx) and particulate matter. The crucial feature is that measurement takes place on the road under realistic driving conditions and not in the laboratory. A device known as a Portable Emissions Measurement System (PEMS for short) is attached to the exhaust of the test vehicle for this purpose.

Euro 6 is the name of the current exhaust emission standard for pollutants. It defines lower maximum values for particulate matter and nitrogen oxide emissions than EU5. From September 2018*, the EU6c emission standard will become compulsory, and in comparison to EU6b it specifies even lower limits for the content of particulate matternumber in petrol-engine vehicles. The same threshold limit values apply for diesel-engine vehicles within the cycle for both EU6b and EU6c. EU6d-TEMP from September 2019* and EU6d from January 2021* will again slightly lower the threshold limit values for the number of particles and nitrogen oxides in line with RDE.
*Applies to new vehicles. New vehicle types will each be subject to the new exhaust emission standards 1 year earlier.

So that the exhaust emission values of a vehicle can be further reduced, liquid ammonia, called AdBlue®, is fed into diesel engines' exhaust system. Selective Catalytic Reduction (SCR) with AdBlue® reduces up to 90% of the nitrogen oxides. What remains is water vapour, nitrogen and CO2. What remains is water vapour, nitrogen and CO2.

BMW uses BluePerformance technology to reduce the nitrogen oxide emissions of its vehicles even further. Thanks to this technology it is possible to further optimise the emissions performance of the diesel drive. In addition to the diesel particle filter and NOx storage catalytic converter, all BMW 4-cylinder diesel engines have an SCR catalytic converter (Selective Catalytic Reduction) with AdBlue® injection to significantly reduce nitrogen oxides contained in the exhaust gases. With the introduction of the new 6-cylinder engine generation for the diesel as from 2020, the storage catalytic converter located close to the engine is replaced by an even more efficient SCR system, also close to the engine. As a result, NOx conversion is further improved, especially during urban driving. A second SCR catalytic converter, located as before in the underbody, provides additional support, and, depending on the vehicle, has its own AdBlue dosing system.

The particle filter is a measure for reducing particulate matter present in diesel engines and petrol engines.

As electric and hybrid vehicles are used mainly in urban areas, WLTP provides, in addition to the four phases of low, medium, high and extra high, a separate 5th phase for them – namely the City Phase. This combines the speeds of the phases that best reflect the motoring situation in urban areas: low and medium. This enables more realistic indications of range to be given.