06-02-2016, 03:18 PM
Introduction
Volkswagen develops environmentally friendly technologies that help reduce CO2 emissions and makes them available throughout the product range. That way, all our customers benefit from our development work. Our technologies reduce the carbon dioxide emissions of the vehicle f leet and play a key role in making vehicles more environmentally compatible. The DSG dual-clutch gearbox, designed to replace
conventional automatic transmissions with torque converters, is a case in point. DSG gearboxes are to be available with almost all the petrol and diesel engine options in the new Golf range and are considerably more efficient than conventional automatic transmissions. Innovations of this type make our models better and improve their environmental compatibility in particular.
Volkswagen uses environmental commendations to document the environmental progress of its vehicles and technologies compared to their predecessors. Our environmental commendations provide our customers, shareholders and other stakeholders inside and outside the company with detailed information about how we are making our products and production processes more environmentally compatible and
what we have achieved in this respect. The DSG dual-clutch gearbox is the first Volkswagen technology to receive an environmental commendation. Our first vehicle environmental commendations, for the Passat and the Golf, were very well received both by the public and by the media.
The environmental commendations are based on the results of a detailed Life Cycle Assessment (LCA) in accordance with ISO 14040/44, which has been verified by independent experts, in this case from TÜV NORD. Volkswagen already has a long tradition in this field: we have been analysing our cars and their individual components for more than ten years, using Life Cycle Assessments to enhance their environmental compatibility. As part of an integrated product policy, the LCA considers not only individual
environmental aspects such as the driving emissions of a vehicle, but the entire product life cycle. This means that all the processes from the production and use of a gearbox right through to disposal are considered in the analysis, “from cradle to grave”.
Summary
This environmental commendation compares current Volkswagen DSG dualclutch gearboxes (6- and 7-speed) with conventional torque converter automatic transmissions. We have assessed the emissions caused by the gearbox not only during use but over its entire life cycle, from production to disposal.
As in the case of the Golf and Passat, the DSG gearboxes show improvements, in some cases significant, in all the environmental impact categories. The greatest advances have been made in the areas of global warming potential (greenhouse effect), acidification and photochemical ozone (summer smog) creation potential. In other respects, such as water and soil eutrophication and ozone depletion, the changeover from conventional automatic transmissions to DSG gearboxes has little impact. It emerged that these improvements were primarily due to reduced fuel consumption and the resultant drop in driving emissions and reduction in environmental impact at the fuel production stage. The reduction in fuel consumption, in turn, is the direct result of the intelligent gearbox management
The DSG dual-clutch gearbox
The DSG intelligent automatic transmission developed by Volkswagen is also an integral part of this strategy for the future. In 2002, Volkswagen presented the first dualclutch gearbox intended for series production, the 6-speed DSG. The dual-clutch principle ensures higher efficiency and lower fuel consumption than a conventional automatic transmission. In addition, it also makes for greater comfort and driving pleasure. In the meantime, Volkswagen has introduced a second dual-clutch gearbox, the 7-speed DSG, which is even more economical and will be used in the future on high-volume models with power outputs up to 125 kW and torque values up to 250 Nm. Since the DSG dual-clutch gearbox was first launched, more than a million units have been sold, resulting in a new boom in automatic transmissions at Volkswagen. The proportion of new vehicles equipped with automatic transmissions has risen dramatically, from 5 to 10 percent with conventional transmissions to as much as 30 percent with the DSG. With the new 7-speed DSG, even more customers will automatically shift up to environmental protection.
Wet or dry
The DSG dual-clutch gearbox developed by Volkswagen combines the comfort and convenience of an automatic transmission with the efficiency and performance of a manual gearbox. Two clutches ensure that shifts take place in next to no time. When a shift is imminent, one clutch disengages while the other is engaging, both in a few hundredths of a second. This is possible because the transmission always preselects the next gear to be used.
Rapid, precise shifting is the key advantage of the DSG over conventional automatic transmissions. With a DSG gearbox, there is no perceptible interruption in tractive force and therefore no jolting during gearshifts. And the dual-clutch gearbox also boasts much higher efficiency, saving fuel and cutting carbon dioxide emissions. And for those who still want to change gears manually, the Tiptronic shift function makes this possible too. Volkswagen offers the 6- and 7-speed DSG gear-boxes for models with various different engines. While the 6-speed DSG, introduced in 2002, is used for high-torque engines up
to 350 Nm, the 7-speed DSG is available for engines with torque figures up to 250 Nm. The key innovation on the 7-speed unit is its „dry“ dual clutch. In contrast to the six-speed DSG, the new transmission does not have a „wet“ clutch with oil cooling. This change results in a whole raft of benefits, all leading to a further improvement in efficiency. With the dual clutch, the efficiency of the DSG gearbox is significantly higher than that of conventional automatic transmissions fitted with hydraulic torque converters. Thanks to the DSG‘s intelligent transmission control system, its outstanding efficiency and its lower weight, vehicles equipped with the 7-speed dual-clutch gearbox may even present lower fuel consumption than comparable manual vehicles, depending on the individual style of driving.
Evaluation
The subsequent final evaluation interprets and evaluates the results of the Life Cycle Inventory and the Life Cycle Impact Assessment. The evaluation is based on the defined goal and scope of the Life Cycle Assessment. CO2
The automatic transmissions assessed
This environmental commendation for the DSG dual-clutch gearbox describes and analyses the environmental impacts of various automatic transmissions. To this end we have compared the current 6-speed and 7-speed DSG units with conventional automatic transmissions equipped with torque converters. The results are based on Life Cycle Assessments drawn up in accordance with the standards DIN EN ISO 14040 and 14044. All the definitions and descriptions required for preparing these Life Cycle Assessments were drawn up in accordance with the standards mentioned above and are explained
below.
The “functional unit” for the assessment was defined as the transmission of torque in a powertrain over a total distance of 150,000 kilometres in the New European Driving Cycle (NEDC). However, within the Volkswagen Group, no vehicle is or has been offered with all three transmissions considered. In order to ensure comparability, it was therefore necessary to base the assessment of the service life phase on fuel consumption simulations. For this purpose, the transmissions were „virtually installed“ on the same reference vehicle, a Golf 1.4 TSI with 90 kW6, and the resulting consumption figures for the entire vehicle were determined on the basis of otherwise unchanged assumptions.
With the exception of the Golf 1.4 TSI with 7-speed DSG, the consumption figures stated are therefore calculated, rather than measured, values7. In line with the functional unit defined above, in what follows we only indicate the resulting consumption benefits compared with the torque converter transmission. This differential approach has also been applied to the production and recycling phases