bluemotion technology.docx

VOLKSWAGEN BLUEMOTION TECHNOLOGIES

ABSTRACT

Human activities are affecting the environment much more and so that every automation company is busy to make its  products and projects very efficient and involving many important steps to achieve this target. And Blue motion Technology is one of them that is used by Volks Wagen group of industries and it tries to decrease the impact of human activity on the environment. Blue motion Technology based cars are known as most cleanest cars and very much Ecofriendly in the world. [More...] Volkswagen group of industry is not depending on the old or space age technology. They are making the car engines more efficient by including the electronic circuitry and by modifying some basic cycle parts of the car engine. By using blue motion technology the car engine gets various useful features like TDI, TSI, DSG, automatic start/stop, Recuperation, usage of taller gear ratios, better aerodynamics etc.The products made by using both blue motion technology and electronic circuitry, are very much efficient and reliable rather than other products.

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1. INTRODUCTION Today the world is become more and more polluted with harmful gases and pollutants like NOx, SOx, HC, CO2, CO... to name a few. The main cause of the atmospheric pollution is our very own automobiles which now have become an integral part of our lives. At this moment replacing all the automobiles with some other alternative is simply not feasible. Due to the increasing pressure fro m the government and other NGO‟s the automobile manufacturers are feeling the pressure which is motivating them to come with some very good ideas to make our future greener, cleaner and much more efficient tan it is today. toda y. The adverse affects that atmospheric pollutants have on humans are: Carbon Monoxide (CO)  –   reduces the

 blood‟s ability to carry oxygen, aggravates ag gravates lung and heart disease, and causes headaches, fatigue, and dizziness. Sulfur Dioxides (SOx)  –  when   when combined with water vapor in the air become the major contributor to acid rain.  Nitrogen Oxides (NOx)  –  cause   cause the yellowish-brown haze over dirty cities, and when combined with oxygen  becomes a poisonous gas that can damage dama ge lung tissue. Hydrocarbons (HC) are a group of pollutants that react to form ozone (O3), some HCs cause cancer and others can irritate mucous membranes. Ozone (O3) is the white haze or smog seen over many cities. Ozone can irritate the respiratory system, decrease lung function, and aggravate chronic lung diseases (such as asthma). Carbon Dioxide (CO2), although naturally occurring, can cause problems. In large quantities it allows more sunlight to enter the atmosphere than can escape  –  trapping   trapping

excess heat that can lead to the “greenhouse effect” and cause global warming. The first idea was to use a hybrid system; generally an electric hybrid is preferred over other kinds of hybrid due to its feasibility in the compact dimensions of a car. But there is a problem with hybrid electric vehicle (HEV). The weakest links are the batteries which stores the electric energy to be used by the electric motor. They are naturally heavy and quick acceleration and deceleration can severely affect the life of the batteries moreover the mining of nickel is a highly polluting process. This is why VolksWagen, which is one of the  biggest automakers of the world, has preferred to go without hybrid systems. The strategy of VolksWagen is to

take the conventional internal combustion engine and make them as efficient as it‟s possible so that the environmental impact of these cars will be greatly reduced. BlueMotion is a trade name (developed externally by UK's Origin Brand Consultants) for fuel-efficient automobile models from the Volkswagen Group. Volkswagen introduced the name in 2006 on the Mk4 Polo BlueMotion, and in 2007 a version based on the current Passat was released. More recently, the technology has  been used in SEAT's models like the SEAT Ibiza or the SEAT León under the name Ecomotive, and in the 2

Škoda Fabia and Superb, where the technology is called Greenline. BlueMotion versions of the Golf and Touran were released in 2008. The name refers to VW's corporate colour, blue, and echoes DaimlerChrysler's BlueTec. BlueMotion Volkswagens use existing technology to improve on the standard engine/vehicle. Currently, Volkswagen Group focuses in three areas of improvement: 

ENGINE: 

Revised engine mapping, and including diesel particulate filters help the fuel consumption and lower NOx levels.



TRANSMISSION: 

On the Polo, Golf and Passat the last two gear ratios are longer than on standard Turbocharged Direct Injection (TDI) engine gearboxes.



AERODYNAMICS: 

On the Polo, Golf and Passat, Volkswagen have lowered the suspension, redesigned the spoilers, and performed additional enhancements underneath each car - so the air is channeled better giving less drag which produces better fuel consumption.

Why the name bluemotion? Blue - the Volkswagen colour - symbolises the elements water and air, while Motion represents a move forwards towards the future. BlueMotion Technologies have one very important aim that is to reduce the impact of cars ca rs on the environment for future generations. Bluemotion cars are not only cleaner, more efficient cars but also offer greater performance. The result is an impressive range of refinements and innovations that save fuel and cut CO2 emissions. All the technologies have been grouped together under the badge of BlueMotion Technologies. So the environmental technologies of today are meeting the driving challenges of tomorrow. At the heart of BlueMotion Technologies are advanced TDI & TSI engines and DSG dual-clutch gearbox. Volkswagen has not only made the car more efficient and eco-friendly but it has made the whole manufacturing  process a lot more cleaner and greener making use of modern highly fuel efficient boilers and furnaces. Preaparing a life cycle assessment(LCA) is a method of understanding the amount of resources going into a car. Volkswagen has many years of experience with Life Cycle Assessments for product and process optimisation. They have even assumed a leading role in implementing and publishing life cycle inventories of complete vehicles. For instance, in 1996 they were the first car manufacturer in the world to prepare a Life Cycle Inventory study (for the Golf III) and publish it [Schweimer and Schuckert 1996]. Since then they have drawn

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up Life Cycle Assessments for other cars and also published some of the results [Schweimer 1998; Schweimer et al. 1999; Schweimer and Levin 2000; Schweimer and Roßberg 2001]. These LCAs primarily describe and identify environmental hot spots“ in the life cycle of a car. ca r. Since then they have broadened the assessments to include production processes as well as fuel production and recycling  processes [Bossdorf-Zimmer et al. 2005; Krinke et al. 2005b]. Since 2007, they have been usuing environmental commendations to inform customers and the public about the environmental properties of their vehicles [Volkswagen AG 2007a, Volkswagen AG 2007b, Volkswagen AG 2008]. Volkswagen is also making long-term investments in further developing and optimising Life Cycle Assessment methods. Thanks to their intensive research they have succeeded in considerably reducing the workload involved in preparing Life Cycle Inventories. Their research resulted in the development of the VW slimLCI interface system [Koffler et al. 2007]: this interface not only significantly cuts the workload involved in  preparing Life Cycle Assessments of complete vehicles by automating the process, but also further further improves the consistency and quality of the LCA models produced. This represents substantial progress, since preparing a complete LCA for a vehicle involves registering thousands of components, together with any related upstream supply chains and processes. Fig. 1 shows the variety of parts involved in an entire vehicle taking the Golf V as an example. All these data has helped Volkswagen to improve the manufacturing process and to reduce the use of conventional fossil fuels in the manufacturing of its cars. Hence the idea of greener cars doesent only starts at the car but it starts from the whole process of manufacturing it.

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Fig. 1: Dismantling study of the Golf V

2. TDI (TURBOCHARGED DIRECT INJECTION) TDI identifies all the VW advanced diesel engines using direct injection and a turbocharger. TDI engines are economical and smooth with high levels of torque (pulling power) and good energy efficiency. Fuel needs oxygen to burn and the engine has to be supplied with huge quantities of air to be effective. This problem is solved using a bigger engine - or by using a turbocharger - as in the TDI. Driven by the exhaust gases, it squeezes air more more tightly into the cylinders. The air is then cooled (cool air takes up less space than hot air) air) and diesel is injected directly into the cylinders at very high pressure through a nozzle. It‟s this intensive mixing of highly atomised fuel with the compressed air that leads to better, more efficient combustion. Makng the driving experience quiet and refined because effective sound insulation keeps noise to a minimum, while hydraulic engine mounts ensure smooth, low-vibration running. The great advantage of TDI engines is that they are very powerful, even at low revs, and economical across the entire speed range. This efficiency also means that one save on fuel costs and emit less CO2, so helping to minimise his/her impact on the environment. 2.1 The Technology

The engine uses direct injection, where a fuel injector sprays atomised fuel directly into the main combustion chamber of each cylinder, rather than the pre-combustion chamber prevalent in older diesels which used indirect 5

injection. The engine is coupled with a turbocharger to increase the amount of air going into the engine cylinders, and an intercooler to lower the temperature (and therefore increase the density) of the air from the turbo, thereby increasing the amount of fuel that can be injected and combusted. These, in combination, allow for greater engine performance (from a more complete combustion process compared to indirect injection), while also decreasing emissions and providing more torque than its petrol engined counterpart. Similar technology has been used by other companies but "TDI" refers to these Volkswagen Group

engines.

 Normally-aspirated engines (those without a turbocharger) made by Volkswagen Group use the label Suction Diesel Injection (SDI). The reduced material volume of the direct injection diesel engine reduces heat losses, and thereby increases engine efficiency, at the expense of increased combustion noise. A direct injection engine is also easier to start when cold, due to more efficient placing and usage usa ge of glowplugs. The PD(Pumpe-Düse) design was a reaction to the development of common rail fuel injection by competitors - an attempt by Volkswagen Group to create create an in-house in-house technology of comparable performance that would not require any royalties to be paid. While Pumpe-Düse engines had a significantly higher injection  pressure than older engines, they were not a match with the very latest common rail, and weren't able to control injection timing as precisely (a major factor in improving emissions). New engines appearing in 2009 model year Volkswagens are using the common-rail technique with piezoelectric injectors. Fuel: TDI engines, like most diesel engines, can run on petrodiesel or B5, B20, or B99 biodiesel subject to manufacturers' prior approval. In fuel efficiency, and clean emissions when run on biodiesel or when converted vegetable oil (which should NOT NOT be used on the the later PD engines without prior conversion, since irreparable damage will result), TDI engines are among the best on the market. This is often overlooked because they do not drive on petrol. A 2007 Volkswagen Jetta 1.9L TDI with 5-speed manual, for example, achieves 5.2 L/100 km (54 mpg UK or 45 mpg US) on the European combined-cycle test while a DSG automatic reaches 5.9 L/100 km (48 mpg UK or 40 mpg mpg US). Newer TDI engines, with higher higher injection pressures, are are less forgiving about poor-quality fuel than their 1980s ancestors. ancestors. VW has recently recently permitted mixes up to to B20, and has recommended B5 be used in place of 100% petroleum-based diesel because of biodiesel's biodiesel's improved lubricating  properties. No. 2 diesel fuel is recommended since it has a higher cetane number numbe r than No. 1 fuel and has lower viscosity (better ability to flow) than heavier fuel oils. Some owners in North America, where cetane levels are generally poor (as low as 40), use additives or premium diesel to get cetane numbers closer to the standard levels found in the European market (at least 51) where the engine is designed.

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Improved cetane reduces reduce s emissions while improving performance and may increase fuel economy. New low-sulfur petroleum-only diesel recipes cause seals to shrink and can cause fuel pump failures in TDI engines;  biodiesel blends are reported to prevent that failure. 2.2 The Turbocharger

To boost power output and torque, VW fitted their TDI engines with exhaust ex haust turbochargers featuring variable turbine geometry. They compress the air required for combustion, letting the engine draw in more air while its displacement and revs stay the same. A turbocharger is powered by the energy in the exhaust gas. It has two connected turbines. The turbine wheel in the exhaust stream drives the intake compressor, which sucks in air through the intake system. The compressed air is cooled by a charge air cooler before entering the combustion chamber. Because cool air is denser than hot air, more oxygen can be fed into the cylinder boosting the efficiency of the combustion process. Overcoming turbo lag: The main disadvantage of a turbocharger is that it needs a certain gas pressure to work which are only available when engine revs are high enough. To avoid 'turbo lag' - a delay in available power the turbocharger needs to be able to control the exhaust pressure at low engine revs. A variable turbine geometry (VTG) turbocharger does this with a system of mechanical guide vanes. These vanes move to adjust the cross-section area to maximise the air flow into the exhaust turbine. Thus at lower speeds, a higher flow can be maintained, increasing the pressure to the compressor and therefore increasing  power output. 2.3 Volkswagen’s Injection Systems

They are one of the leaders in developing advanced efficient diesel engines with lower emissions. Their innovative engines are progressively meeting the new EU 5 standard, ahead of legislation. Their range of three to ten-cylinder turbodiesel engines are based on u nit injector systems, and common rail injection. Table 1: Comparison between different VW engines. VW Polo 1.6

VW Polo 1.6 TDI

VW Polo 1.4 MPI

TDI

BlueMotion Technology

DSG

Engine capacity [cm3]

1598

1598

1390

Output [kW]

55

66

63

Gearbox

5-speed manual

5-speed manual

7-speed DSG®

7

Fuel

Diesel

Diesel

Petrol (Super)

(5.1/3.6/4.2)

(4.6/3.2/3.7)

(7.7/4.7/5.8) (7.7/4.7/5.8)

Emission class

Euro 5

Euro 5

Euro 5

CO2 emissions; combined [g/km]

109

96

135

works?

Maximum speed [km/h]

170

180

177

The

Acceleration 0-100 km/h [s ]

13.9

11.5

11.9

 pressure at

Kerb weight [kg]

1157

1165

1104

which

the

diesel

is

Fuel consumption [l/100 km] (urban/overland/combined)

How injection

injected into the cylinder is the key factor in diesel direct injection. The fuel has to mix swiftly with the compressed air in the cylinder. The higher the pressure, the more finely the diesel is atomised for an intensive mixing of the fuel and air particles. This, in turn, leads to better and more efficient combustion process. The energy from the fuel is used more effectively and emissions are reduced. We use various injection stages within one power stroke - referred to as multiple injections. Depending on the engine design, revs and load, modern diesel engines use a pilot or double pilot injection and a main injection. Pilot injection achieves smooth combustion, ensuring that the extremely high pressures necessary for combustion to take place are are reached more gradually. This significantly reduces combustion noise and cuts emissions. Piezo crystal injectors. To control the injection process precisely and cut fuel consumption and emissions significantly, they use piezo inline injectors instead instead of solenoid valves. They are lighter and respond twice as fast. This enables the injector valve to to switch five times faster faster to meter the fuel fuel and control the injection curve far more precisely, resulting in a smoother, quieter and more efficient combustion process. A post injection  phase is also possible with this type of injector, which helps the exhaust emissions system to be more efficient and results in lower Common

rail

diesel rail

is

emissions.

-

third-generation

direct

injection. Common

latest

diesel

the

engine

technology and is

used in many VW

vehicles

The common rail

system

already. stores

the

injection

pressure

in a high-pressure

fuel

reservoir

referred to as the

„common

rail‟ as

it supplies all the

injectors.

In this

8

system the generation of pressure and the fuel injection p rocesses are separate.

Figure 2: Comparison between the TDI and normal diesel engine. Lines connect all the cylinder injectors to the common rail in parallel, ensuring they all have an uninterrupted supply of constant pressure. The injection quantity and timing are controlled using solenoid valves. The advantage of common rail is that fuel can be delivered at higher pressure, giving better mixing with air for a more efficient and cleaner combustion. This gives higher performance combined with improved fuel consumption. The ever-higher injection pressures that make diesel engines cleaner and more efficient than before place big demands on the common rail system. Their latest generation of diesel engines reaches injection pressures as high as 1,800 bars. For this reason the y make the rail themselves, and they the y are the first car maker to do so. so . 2.4 Diesel Particulate Filters (DPF)

The main problem with diesel engine is the amount of soot emission. This is why diesel particulate filter is an integral part of any diesel engine. The diesel particulate filter: Legislation is continually driving car manufacturers to produce cleaner and more environmentally friendly vehicles. Their advanced diesel engines meet this challenge and are cleaner than ever before. One important factor is their diesel particulate

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filters (DPF), which are very effective in cutting particulate emissions, trapping even the finest soot particles that are produced as the engine burns diesel fuel. The

latest generation of filters filters operate without additives. This makes them maintenance-free for an

exceptionally long time: an initial inspection is usually carried out only after 150,000 km. The filter's lifespan is dependent on factors such as fuel quality, qualit y, driving style, use and oil consumption.

3. TSI (REVOLUTIONARY PETROL ENGINE)

What is TSI? TSI is VW‟s pioneering tec hnology for petrol engines. TSI engines are compact, high-powered and use less fuel. TSI technology blends the best of their TDI diesel and FSI (Direct Injection) engines. One can enjoy excellent drivability and outstanding fuel economy. Acceleration is instant, whichever gear one is using. So overtaking is safer and one can power smoothly up hills with no delay. TSI technology is available on an increasing number of VW‟s cars, from Golf to Passat. As responsible car makers VW wanted to make its petrol engines even cleaner and more efficient, while still  being fun to drive. Their aim was to create engines that used less fuel and produced lower CO2 emissions without sacrificing power. The solution their engineers came up with was w as both bo th elegant and ingenious: an engine that combines petrol direct injection with twincharging –  a   a turbocharger and a supercharger working together. The TSI engine was born. Volkswagen is the only car manufacturer in the world to offer an engine with this feature. The effect is to combine the benefits of both petrol and diesel power units: smooth and quiet on the road, TSI delivers high torque - pulling power - throughout the acceleration range with no turbo lag. The successful TSI formula combines a number of different elements: 3.1 Smaller Engines

At the heart of TSI is a smaller engine. It's more efficient, efficient, as there is less power loss resulting from from friction. It's also lighter, so the engine has less weight to shift in the car. Direct petrol injection with charging. Direct petrol injection is combined with a turbocharger or with a turbocharger and a supercharger working in tandem. This enhances the engine's combustion efficiency so the TSI engine power output is much higher than that of conventional, naturally aspirated engines. Hunting down every gram: The 140 PS and 170 PS TSI engines are already lightweight. Even then consistent efforts were made to reduce the weight of the new TSI even more. Its pistons and valve reliefs were designed as lightweight castings, and the geometries of the asymmetrical stem and wall thicknesses were also optimized to handle their loads. That is how weight was trimmed gram for gram. On the cylinder head, whose fundamental 10

concept is also based on the stronger TSIs, it was possible to reduce weight by about 600 grams with a structure-optimized design. The Volkswagen engineers also reconfigured the intake port. Based on the large TSI, it was further developed with the goal of achieving a level of swirl or tumble that would not require charge movement flaps, as already mentioned. In addition, the new intake port was modified substantially. The advantage: In broad sections of the engine's operating range, it was possible to achieve quicker and even more efficient combustion with better fuel economy and a smoother engine characteristic. Valves on the TSI are actuated by two camshafts also further optimized with inlet-side adjustment. Various modifications enabled weight savings here too: The camshafts each weigh 304 grams less. Every gram counts. That is why even the cylinder head cover is 150 grams lighter. Overall, the 90-kW TSI is 14,000 grams, or 14 kilograms, lighter than a TSI with 125 kW. 3.2 Twincharging

On the TSI 1.4 160PS the engine-driven supercharger operates at lower revs, with the turbocharger - powered  by the exhaust gases - joining in as engine speed rises. The supercharger is powered via a belt drive directly from the crankshaft. This provides maximum pulling power on demand, even at very low engine speeds. TSI engines are designed to deliver maximum torque from engine speeds as low as 1500 or 1750 rpm. And that has the twin benefit of not only increasing your driving pleasure but also cutting fuel consumption. The turbochargers are compact and therefore weight-optimized in design too. In keeping with the overall concept, the best dynamics and lowest fuel consumption were top priorities. The very quickly responding turbocharger and the very narrow intake and exhaust cams, together with intake camshaft adjuster, are also responsible for making 80 percent of the 200 Newton-meter maximum torque available at a low 1,250 rpm. The refined flow optimization of the integral exhaust manifold and a very carefully optimized exhaust turbine also deliver excellent, low-loss charger operation, even at high speeds. The maximum speed of the turbocharger is 220,000 rpm. Integrated directly in the compr essor housing of the charger is the electrically-controlled divert-air valve. Its advantage compared to a pneumatic valve: Its construction is more compact and less complex. In addition, it produces significantly shorter switching response times, so that the turbocharger always operates optimally, even with abrupt throttle adjustments. An electrically-controlled divert-air valve was introduced for the first time on the turbo engine on the current Golf GTI. An innovation on the new TSI is its water-flow intercooler, which is positioned right in the intake port. It is part of a low-temperature circulation loop that is independent of engine cooling. The advantage here: The charge air system exhibits a lower volume than in conventional approaches that use a front intercooler. Numerically speaking, it was possible to reduce the volume from about 11.0 to 4.8 liters. This significantly shortens the time 11

required to reach a charge pressure of 1,800 millibar in the intake port. The results: Improved dynamics due to minimal delays in filling the combustion chamber to its maximum. And the driver of a Volkswagen equipped with the 122-PS TSI can experience ex perience this dynamic gain. Latest developments: They never stopped refining their TSI technology. Some of their latest ideas for the 1.4 122 PS include: More ways to save save weight. These range from a lightened lightened cylinder head cover and a weight saving per camshaft to the refined design of the cylinder head itself. A new injector with six fuel bores for electronic direct injection helps achieve this. The injector jets have been realigned to give more efficient distribution of the fuel mixture in the combustion chamber. Supercharger boosts pressure at low end: To increase torque at low engine speeds, engine developers selected a supercharger that is mechanically-driven by a belt. This charger is based on the Roots principle. A special feature of the supercharger being used is its internal gearing stage located in front of the synchronization gear  pair, which enables high supercharger boost performance at low engine speeds. Turbocharger kicks in at the upper end: At higher engine speeds the turbocharger (with wastegate control) kicks in. The supercharger and turbocharger are arranged in series here. The supercharger is actuated by a magnetic clutch integrated in a module within the water pump. A control flap ensures that the necessary fresh air is supplied to the turbocharger or supercharger for the given operating point. In pure turbocharger operation the control flap is open. The air then takes the route of conventional turbo engines, via the front intercooler and throttle valve and into the intake port. The maximum charge pressure of the twincharger is approx. 2.5 bar at 1,500 rpm. Only in the lower speed range below 2,400 rpm is the supercharger needed to generate the necessary charge pressure. The turbocharger is designed for optimal efficiency in the upper performance range, and it also supplies sufficient charge pressure in the middle speed range. 3.3 Charge-Air Intercooling

The turbocharger has a water-cooled intercooler with a low-temperature circuit independent of the engine cooling system. As As a result we've we've cut the volume of the charge air system by more than half, allowing a high charge pressure to build up much more quickly. This gives improved dynamics because it it reduces the time it takes to achieve maximum charge in the combustion chambers. The first car in the world to have TSI on board was the Golf GT. The 125 kW / 170 PS power and 240 Newtonmeters of torque on this small brother of the Golf GTI contrast with a low 7.2 liters per 100 kilometers average fuel consumption. This sporty Golf races to the 100 km/h mark from a standstill in just 7.9 seconds. And at 220

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km/h it has reached its top speed. Standard equipment on the Golf GT includes a six-speed transmission, but available as an option on this Volkswagen too is the technically unique DSG dual clutch transmission. Meanwhile, the large TSIs paired with DSG are not just reserved for the Golf; the engine and transmission are available today on the Golf Plus, Golf Variant, Jetta and Touran too. Representing the technical foundation of 3

the TSI on the new, small TSI with 90 kW, for example is a 1,390 cm   displacement four-cylinder engine, whose dynamics, in the case of the GT, match those of a 2.5-liter naturally aspirated engine. The TSI already develops its maximum torque at 1,750 rpm, which is then constantly in reserve up to 4,500 rpm. The second TSI is the engine version debuting in 2006 on the Golf, Jetta and Touran with 103 kW / 140 PS. TSI stands for a new type of downsizing: For less displacement, less fuel consumption, lower emissions, yet more power, more torque and more driving fun. The 140-PS TSI develops 220 Newton-meter torque at a low 1,500 rpm and holds this value constant up to 4,000 rpm. To ensure that driving fun is not spoiled when refueling, all TSI engines are designed to operate with economical, super 95 ROZ fuel. 3.4 Advanced Injection Technology

Electronic direct injection is marked by a newly developed high-pressure injection valve with six fuel spray holes. Background: A multi-hole high-pressure injection valve of this type was first used on the large TSI engines. However, on the small TSI the spray behavior was significantly modified. The fuel mixture is distributed more efficiently in the combustion chamber thanks to a new design of the six injection jets adapted to the specific needs of this engine. This enabled ignition timing adjustment, and one result was significantly lower HC emissions (hydrocarbons). The injector itself is arranged on the intake side between the intake port and the cylinder head gasket level; the maximum injection pressure is 110 bar. b ar.

4. DIRECT SHIFT GEARBOX (DSG) Their acclaimed Direct Shift Gearbox (DSG) has two clutches with electronically controlled gear selection. DSG gives: Fast, smooth gear changes; lively handling with unbroken acceleration; Safer driving with the  power to get you out of tricky situations; Improved fuel economy, even compared to a manual gearbox, for many of their new 7-speed DSG „boxes. 4.1 Working

DSG is a groundbreaking 'two-in-one' concept. Available in 6-speed and 7-speed versions, it's totally unlike a conventional automatic transmission.

Twin electronically controlled shafts manage gear selection, always

anticipating your next shift. When one turn the engine on and select Drive mode, one shaft selects first first gear 13

while the second shaft puts the next gear on 'standby'. As the gearbox changes to second, the second shaft is engaged and the original shaft reaches third. As you shift upwards the sequence continues in a series of seamless moves. Because power is simply switched from one shaft to another, not only are gearshifts silky smooth, but they are also very fast: each change takes less than four-hundredths of a second. The DSG gearbox gives a choice of two driving programmes: normal and sport. In sport mode, the DSG leaves it longer to shift shift up the gears. And if one wants to take over, he/she can control the DSG manually. Nudge the Tiptronic gearlever forwards or backwards to change gear, or use the paddle shifts mounted on the steering wheel: left for down, right for up. Both DSG gearboxes are application-specific. The 6-speed is paired with high torque engines (up to 350 Nm) while the 7-speed variant is more effective in combination with smaller engines and torque outputs of up to 250 Nm. 4.2 The Technology :

The 6 speed DSG gearbox is made up of two independent gearbox units. With dual-clutch technology - two clutches in a common housing - both gearboxes are connected under load to the engine in turn, depending on the current gear, via two drive shafts. Clutch 1 serves the first gearbox unit with 1st, 3rd, 5th 7th and reverse gear and clutch 2 the second gearbox unit with 2nd, 4th and 6th gear. An output shaft that applies the torque to the driven wheels via the differential gear is assigned to each gearbox unit. Thanks to the dual-clutch design the DSG is more efficient than conventional automatic transmission. This efficiency, together with its low weight and intelligent control, means that DSG can achieve the same, and in some instances better, fuel consumption, than a manual gearbox or even lower, depending on the style of driving. 4.3 Mechatronics

Electronics and mechanics in one unit. Clutches and gearbox units are operated hydraulically by the gearbox mechatronics (a combination of mechanics and electronics) housed h oused in the DSG. The electronic transmission control unit, sensors and hydraulic control unit form one compact unit.

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The control unit does the thinking for you, using information such as engine speed, road speed, and accelerator  position and driving mode to select the optimum gear and to determine the ideal shift point. The hydraulic control unit then implements the shift commands in a sequence of precisely co-ordinated actions. act ions. Figure 3. Schematic diagram of a 7 speed DSG gearbox. Split-second gear changes: When

one

gear

is engaged,

another is

gear always

 preselected. Within

four

hundredths of a second after the

system

detects a gear change

it

opens one clutch and closes the other. The mechatronics unit ensures that this takes place fast and to a level of accuracy that would not be possible in a manual transmission. The change of gear is imperceptible to the driver who is merely conscious of the uninterrupted power. 4.4 DSG 7-Speed Gearbox

The new 7-speed DSG gearbox is a world first. first. What makes it so innovative is its pair of dry clutches which

have dispensed with the need for the oil bath of conventional „wet‟ clutches. They have been designed to improve fuel efficiency and driving agility further. The clutches' dry, organic-bonded friction linings need no cooling. The gearbox is also very compact and requires less power for the gear selection and clutch servo system. Ideal for motorway driving. Adopting 7 speeds meant our engineers could lower 1st gear to improve acceleration from standstill standstill and raise 7th gear to act as an overdrive function, ideal for motorway driving. This can save fuel, cut emissions, and means the car runs even more quietly. Table 2: Comparison between different automatic gearboxes 15

Automatic Transmissions

Torque converter transmission

6-speed DSG

7-speed DSG

 Number of gears gears

6

6

7

Max. torque

320 Nm

350Nm

250Nm

Clutch

-

Wet

Dry

Transmission Transmissio n oil volume

5.8l

6.5l

1.7l

Weight

85Kg

93Kg

77Kg

Consumption advantage

baseline

-0.3 l/100 km

-0.8 l/100 km

Efficiency

83%

85%

91%

Figure

4. Dual

clutch. The recently developed dual clutch is one of the most radical developments which helped make the DSG such a ground breaking innovation. Being a dry clutch its not only better in terms of performance but is much lighter than its earlier counterpart. Figure 4 shows a cutaway diagram of the dual clutch used in the 7 speed DSG gearbox. Besides core power train and drivetrain components Volkswagen has also made improvement in other  peripheral equipments related to the car as explained below. Inorder to make the car better not only in the field of performance but also helping it become more eco friendly.

5. AUTOMATIC START/STOP Driving in towns involves a lot of stopping and starting, waiting in queues or at traffic lights. And while the engine is ticking over , it‟s using fuel. VW‟s efficient Start/Stop technology, introduced on the Passat BlueMotion, stops this waste, cutting CO2 emissions and saving fuel. The Start/Stop system means that the car can virtually stop its engine by itself. It works through the clutch, so when the car come to a standstill, one has to

just select neutral gear, release the clutch and the engine eng ine switches off o ff with a Start/Stop

symbol appearing on the dashboard. When he/she wants to move off again he/she has to simply dip the clutch, the engine restarts and you can select first gear and pull away. The system can easily be deactivated, if one wishes, by a switch within easy reach. 16

6. RECUPERATION When one is trying to save energy while driving it makes sense to recover it where one can. VW uses improved alternators and batteries in combination with an energy management system, to store kinetic energy that would normally be lost during slowing down or braking. The un-utilized alternator voltage during slowing down or  braking is used to add extra charge to the battery during this period. This extra battery charge can then be utilised during acceleration or starting, instead of drawing all the energy from the alternator, thus  placing less of a burden on the engine and reducing fuel consumption. Recuperation is a feature of some of our BlueMotion cars. Along with it the car is fitted with low rolling resistance tyres. They need less engin e power to move the car forward, saving fuel and helping to cut emissions, while still offering excellent performance.

7. GEAR RATIOS Manual gearboxes with optimised gear ratios are another way of saving fuel. The longer gear ratios for the higher gears reduce consumption. The lower engine speed also cuts noise - both for those in the car and those outside it. Fuel saving also depends on how the car is driven and some BlueMotion models are fitted with a system that indicates a recommended gear, giving one the opportunity to adjust your driving style for greater economy. According to the driving situation, the intelligent engine management recommends the most efficient gear in the multifunction display. An arrow pointing upwards tells you to move up a gear, and an arrow pointing down recommends a lower gear. If the gear already selected is the best one for the current speed, a dot appears.

8. AERODYNAMICS: The smoother the airflow over your car as it goes forward, the less drag there is holding it back and the less effort is needed to move the car forward. That means better performance and lower fuel consumption. That's why VW constantly optimises the aerodynamics of the ca rs they manufacture by: 

The body is more steamlined and gaps between panels are narrower.



Headlights and indicators are combined.



Radiator grilles, underbody panels and spoilers are designed to reduce drag.

A very slight change in the drag coefficient of a car can help alter the performance of the car significantly, especially when travelling at high speeds on the highway most of the power produced by the cars goes on to overcoming the aerodynamic drag so it becomes essential to optimize the aerodynamic performance of the car in order to make it efficient at high speeds.the greater the speed the greater will be the affect of aerodynamics on the cars performance for example the worlds fastest car Bugati Veyron has a 1000bhp engine, out of which 17

250bhp is enough to propel the car to a speed of 300kmph but for the remaining 100 odd Km/H it requires the extra 750bhp. A comparison between the coefficients of drag of different Bluemotion cars and the normal cars shows the improved aerodynamics of these cars. In table 3 there is a comparison between the Cd values of different car models. 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Maruthi 800

Maruthi Alto

VW Beetle (new)

VW Tiguan

VW Passat Bluemotion

VW 1 litter concept

Figure 5: Comparison between automobile drag coefficients (Cd).

9. CONCLUSION With the increase in number of vehicles on road it is becoming much important that we make them cleaner and greener. All the bluemotion technologies together increase the efficiency of an ordinary diesel engine from 38% to about 43% and of a petrol engine from 32% to 36%.

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Figure 5: Trend of CO2 emissions during different years From the graph above its evident that a little change today can mean a much better tomorrow so these small changes can help in contributing a lot to the future generation. Proper, timely maintenance is essential to make the car efficient throughout its life, a VW study suggested that proper timely maintenance of simple things like tyre pressure, engine oil, etc can help save the fuel and thus reduce the emissions.

REFERENCES i.

aerodynamics, Cambridge University Press, Edition: 2 –  2001.  2001. Joseph Katz, Allen Plotkin;  Low-speed aerodynamics, Cambridge

ii.

Robert Bosch GmbH,  Diesel-engine management, Robert management, Robert Bosch GmbH, 2003.

iii.

Herbert Frank Percy Purday     , CRC Press, Edition: 5.

iv.

Alec Stokes Manual gearbox design, Society of Automotive Engineers, Edition: 3.

v. vi.

http://www.volkswagen.co.uk/technology/bluemotion. http:// http://www.nas.nasa.gov/About/Education/Racecar.

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