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Wolfsburg, 29 August 2005 - The new Golf GT to be launched at the end of 2005 will close the gap between the die Golf Sportline and the Golf GTI. The GT will hit the market in Europe with two engine models, each with 170 HP: The innovative 1.4 l Twincharger and the equally powerful 2.0 TDI with diesel particulate filter as standard.
DESIGN - individual appearance for the GT with special front section
The Golf GT is not just a very special Golf under the engine hood, it also looks special. The new front section with its V-shaped radiator grille in the body colour is the exclusive preserve of the new Golf GT. Air inlet openings are integrated into the front bumper, but are more understated than in the GTI. In this way, the designers have clearly distinguished between the Golf, Golf GT, Golf GTI and R32, thereby making it clear that the models have different power levels. There is an opening for the twin tailpipe in the rear apron. The GT is 15 millimetres lower than the standard level and sports 17-inch wheels.
POWERFUL YET FRUGAL 170 PS ENGINES:
1.4-litre TSI with 125 kW / 170 PS and
2.0-litre TDI with 125 kW / 170 PS
As well as the 1.4 l Twincharger with 125 kW / 170 HP described in detail above, Volkswagen is also launching the Golf GT with the most powerful diesel engine on the market and the most powerful that has ever been available ex-works in a Golf: the 2.0 TDI with 125 kW / 170 HP: The exceedingly frugal Golf GT 2.0 TDI is exciting to drive because it offers impressive power reserves in all situations. The direct-injection pump/nozzle turbo diesel with piezoelectric elements, four-valve technology, two overhead camshafts and a diesel particulate filter as standard develops 125 kW / 170 PS at 4000 rpm. Its torque curve reaches an imposing maximum of 350 newton metres on a plateau of 1800 to 2500 rpm. The performance figures for this, the most powerful Golf TDI ever, are convincing across the board: It achieves a maximum speed of 220 km/h (136 mph) and accelerates from stationary to 100 km/h (62 mph) in only 8.2 seconds; and all this with a consumption of only 5.9 l/100 km (47.9 mpg) diesel.
GEARBOX - Golf GT always with six gears – manual or direct shift gearbox
As standard, the engine power is channelled to the driven front wheels through a manual six-speed gearbox. From early 2006, it will also be possible to combine these engine versions with the crisply shifting six-speed DSG direct shift gearbox. Connoisseurs will lick their lips at this, since the DSG combines the convenience of an automatic with the sporty and fuel-saving advantages of a manual. It has six forwards gears, shifts gear extremely quickly and without any interruption in traction. The DSG is the ideal gearbox particularly in combination with turbo diesel direct injection engines, and now also with the new “Twincharger”. Background: The DSG is the first gearbox to do full justice to the consumption benefits of the innovative engine technology in spite of the automatic gearshift function – indeed, it even adds to the benefits. Like the classic Tiptronic, this gearbox can also be shifted manually using a plus/minus gearshift gate.
EQUIPMENT - Understated sportiness
Externally, the Golf GT can be recognised by its modified front section that is similar to the GTI whilst nevertheless retaining its individuality. For example, the V-shape is developed but is much more understated than in the GTI. Further special optical cues include the GT logos on the front and fear as well as special alloy wheels and the visible twin tailpipe. The standard equipment of the Golf GT is based on the Trendline and includes electric front windows, electrically adjustable and heated outside mirrors, central locking with radio remote control, six airbags, headrests and three-point seat belts for all five seats, electromechanical power steering as well as ABS with electronic stability programme (ESP) and traction control (ASR).
The dynamically set-up Golf GT, whose two available 170 PS power plants enable it to achieve excellent performance, has a sports chassis lowered by 15 millimetres, 17-inch alloy wheels in the “BBSClassiX” design with 225/45 R17 tyres. The 16-inch brakes (as in the Golf GTI) combined with the brake assistant ensure that the Golf GT, both in the guise of the compressor-turbo and the most powerful TDI in the compact class, can be reined in safely.
In the interior, the Golf GT will appeal with special sports seats in the individual “Brick” design, a three-spoke leather steering wheel with GT logo and a boost pressure display in the cockpit (TSI).
Twin-turbocharged FSI engines - Central aspects
Wolfsburg, 29 August 2005 - At the International Motor Show (Cars) in Frankfurt, Volkswagen is presenting to the general public a ground-breaking innovation in the drive sector: The world’s first twin-turbocharged FSI engine – the “Twincharger”. The compact 1.4 litre direct-injection engine develops up to 125 kW / 170 PS and has a maximum torque of 240 newton metres in the range from 1750 to 4500 rpm thanks to the combination of an exhaust turbocharger with a mechanically driven compressor.
The 1.4 litre engine delivers a power output of 90 kW / 121 PS per litre, representing a peak value for a series production four-cylinder engine. Furthermore, the “Twincharger” delivers a torque corresponding to a naturally aspirated engine with a swept volume of approx. 2.3 litres. And its fuel consumption is around 20 percent lower.
Another performance variant of this innovative TSI engine with 103 kW / 140 PS (maximum torque 220 newton metres) will be available from early 2006, initially in the Touran compact MPV, and after that the Golf will also be available with this engine.
THE TASK
Reducing consumption values – Increasing driving performance
It is the declared objective of European car makers to reduce CO2 emissions. This will be done in various steps, to a value of 140 grams per kilometre. Reduction in CO2 emissions goes hand-in-hand with a reduction in fuel consumption. Achieving this ambitious target will require a combination of the latest engine technology with driveline optimisation.
However, this is not enough. As well as the consumption reduction, it was specified that there had to be a full torque characteristic combined with a high standard of quality and a long service life. In addition, the engine had to be compact to allow it to be integrated into many different vehicle concepts. And, it would have to be designed to enable straightforward production in high quantities. Another target was concerned with resolving numerous conflicting objectives in an innovative way. To cut a long story short – we succeeded.
THE CONCEPTUAL IDEA
A compact FSI engine with twin, different supercharging as an approach to the solution
The most effective way to reduce consumption is referred to as downsizing. A reduction in cubic capacity and therefore lower friction losses result in a low specific consumption, which equates to better efficiency. However, an engine with a low cubic capacity only meets the current requirements for active road safety and pleasurable driving to a very limited extent. As a result, the objective can only be achieved by supercharging. Classic turbo engines with a small cubic capacity supercharged using exhaust turbochargers have only been used to a very limited extend in the past since they have low moving-off power and are therefore less acceptable. This problem can be solved by a mechanically driven supercharger that supplies additional fresh air to the engine even at low speeds. The challenge was to combine these two systems in a rational way.
The only candidate for injection technology was the FSI technology that is now used by Volkswagen in numerous model ranges. Experience gathered during the last few years by engine developers at Volkswagen in this injection technology had revealed that FSI could be ideally complemented by the two different supercharging techniques, the result being a previously unheard of increase in efficiency.
This gave rise to the world’s first direct-injection SI engine with twin supercharging for use in high-volume series production – the “Twincharger”.
THE IMPLEMENTATION
Compressor for power at low speeds, turbocharger for power at high speeds
The choice for the basic power unit was the FSI from the EA 111 engine series as used in the Golf in power levels of 66 kW / 90 PS (1.4-litre) or 85 kW / 115 PS (1.6-litre). The 1.4-litre engine is a four-valve four-cylinder engine with a swept volume of 1390 c.c., a cylinder gap of 82 millimetres and a bore/stroke ratio of 76.5 to 75.6 millimetres. The focus in developing the “Twincharger” engine was placed on designing a new, highly resilient grey cast iron cylinder crankcase in order to withstand the high pressure of up to 21.7 bar over long periods, a water pump with integrated magnetic clutch and supercharging technology.
However, the injection technology was also modified. A multiple-hole high-pressure injection valve with six fuel outlet elements is used for the first time in the 1.4 l TSI engine. The injector, like that in the naturally aspirated FSI engines, is arranged on the intake side between the intake port and cylinder head seal level. The quantity of fuel to be injected between idling speed and the 90 kW/litre output power requires a wide variability in the fuel flow through the injectors – given a sufficient mixture preparation time after completion of injection under full-load conditions on the one hand and idling speed with reproducibly low injection volumes on the other hand. The maximum injection pressure was increased to 150 bar in order to achieve this wide range of throughflow. Furthermore, only FSI technology made it possible to achieve a compression ratio of 10:1 which is high for supercharged engines.
The Volkswagen engine developers selected a compressor with a mechanical belt drive in order to increase the torque at low engine speeds. This is a supercharger unit based on the Roots principle. One special feature of the compressor used is its internal step-down ratio on the input end of the synchronisation gear pair.
The exhaust turbocharger also kicks in at higher engine speeds (with wastegate control). The compressor and exhaust turbocharger are connected in series in this case. The compressor is operated by a magnetic clutch integrated in a module inside the water pump. A control flap ensures that the fresh air required for the operating point can get through to the exhaust turbocharger or the compressor. The control flap is open when the exhaust turbocharger is operating alone. In this case, the air follows the normal path as in conventional turbo engines, via the front charge-air cooler and the throttle valve into the induction manifold.
One of the major challenges facing the development was to achieve the best possible interplay between the two superchargers arranged in series. Only when both units – the compressor and the exhaust turbocharger – complement one another optimally can the small power unit achieve its required, level torque characteristic over a broad engine speed range in conjunction with a previously unheard of increase in efficiency.
THE RESULT
A twin-turbocharged FSI with two power levels
The ambitious objective of squeezing an output per litre in excess of 90 kW per litre swept volume out of a 1400 c.c. engine could not be achieved with single-stage supercharging alone. However, an upstream compressor enables the boost pressure buildup of the exhaust turbocharger to be significantly increased.
The maximum boost pressure of the “Twincharger” is approx. 2.5 bar at 1500 rpm, with the exhaust turbocharger and the mechanical supercharger being operated with about the same pressure ratio (approx. 1.53). A straight exhaust turbocharged engine without compressor assistance would only achieve a pressure ratio of about 1.3 bar here. The more rapid response of the exhaust turbocharger enables the compressor to be depressurised earlier by continuous opening of the bypass valve. This means compressor operation is restricted to a narrow map area with predominantly low pressure ratios and, therefore, low power consumption. Consequently, the disadvantage of the mechanical supercharger system in terms of consumption can be limited.
In practice, this means the compressor is only required for generating the required boost pressure in the engine speed range up to 2400 rpm. The exhaust turbocharger is designed for optimum efficiency in the upper power range and provides adequate boost pressure even in the medium speed range. In dynamic driving, this is inadequate for the specified in-gear acceleration values in the low engine speed range. In these driving situations, the compressor is engaged to permit a spontaneous boost pressure buildup. The way in which these two systems complement each other means there is absolutely no turbo lag. The compressor is no longer needed above an engine speed of 3500 rpm at most, as the exhaust turbocharger can definitely provide the necessary boost pressure even dynamically during the transition from coasting to full-load operation.
THE DRIVING EXPERIENCE
High performance and torque produce low consumption and enormous driving pleasure
The compressor, with its high ratio of 1:5 in relation to the crankshaft, delivers a boost pressure of 1.8 bar even just above idling speed. This provides the power needed when moving off. An electromagnetic clutch integrated in the module of the coolant pump is responsible for switching the compressor on and off. It is driven by an additional belt. A torque of 200 newton metres is available at a speed of only 1250 rpm – and all the way through to 6000 rpm. In dynamic compressor mode, the automatic boost pressure control decides whether the compressor will be switched on in accordance with the tractive power required, or if the turbocharger alone can generate the necessary boost pressure. The compressor is switched on again if the speed drops to the lower range and then power is demanded again. The turbocharger alone delivers adequate boost pressure above 3500 rpm.
In practice, the “1400 Twincharger” drives like a big naturally aspirated engine with 2.3-litre cubic capacity. This is because the maximum torque of 240 newton meters is available from 1750 rpm to 4500 rpm. The boost pressure gauge installed as standard in the cockpit of the Golf GT 1.4 TSI is the only signal of the furious activity being undertaken by the superchargers and the complex procedure of harmonizing both systems taking place under the engine hood. The driver likes it, because when the needle is fully deflected then the acceleration really presses the occupants back into their sports seats (fitted as standard).
[IMG]Power/torque characteristic of 1.4 TSI 125 kW[/IMG]
DESIGN - individual appearance for the GT with special front section
The Golf GT is not just a very special Golf under the engine hood, it also looks special. The new front section with its V-shaped radiator grille in the body colour is the exclusive preserve of the new Golf GT. Air inlet openings are integrated into the front bumper, but are more understated than in the GTI. In this way, the designers have clearly distinguished between the Golf, Golf GT, Golf GTI and R32, thereby making it clear that the models have different power levels. There is an opening for the twin tailpipe in the rear apron. The GT is 15 millimetres lower than the standard level and sports 17-inch wheels.
POWERFUL YET FRUGAL 170 PS ENGINES:
1.4-litre TSI with 125 kW / 170 PS and
2.0-litre TDI with 125 kW / 170 PS
As well as the 1.4 l Twincharger with 125 kW / 170 HP described in detail above, Volkswagen is also launching the Golf GT with the most powerful diesel engine on the market and the most powerful that has ever been available ex-works in a Golf: the 2.0 TDI with 125 kW / 170 HP: The exceedingly frugal Golf GT 2.0 TDI is exciting to drive because it offers impressive power reserves in all situations. The direct-injection pump/nozzle turbo diesel with piezoelectric elements, four-valve technology, two overhead camshafts and a diesel particulate filter as standard develops 125 kW / 170 PS at 4000 rpm. Its torque curve reaches an imposing maximum of 350 newton metres on a plateau of 1800 to 2500 rpm. The performance figures for this, the most powerful Golf TDI ever, are convincing across the board: It achieves a maximum speed of 220 km/h (136 mph) and accelerates from stationary to 100 km/h (62 mph) in only 8.2 seconds; and all this with a consumption of only 5.9 l/100 km (47.9 mpg) diesel.
GEARBOX - Golf GT always with six gears – manual or direct shift gearbox
As standard, the engine power is channelled to the driven front wheels through a manual six-speed gearbox. From early 2006, it will also be possible to combine these engine versions with the crisply shifting six-speed DSG direct shift gearbox. Connoisseurs will lick their lips at this, since the DSG combines the convenience of an automatic with the sporty and fuel-saving advantages of a manual. It has six forwards gears, shifts gear extremely quickly and without any interruption in traction. The DSG is the ideal gearbox particularly in combination with turbo diesel direct injection engines, and now also with the new “Twincharger”. Background: The DSG is the first gearbox to do full justice to the consumption benefits of the innovative engine technology in spite of the automatic gearshift function – indeed, it even adds to the benefits. Like the classic Tiptronic, this gearbox can also be shifted manually using a plus/minus gearshift gate.
EQUIPMENT - Understated sportiness
Externally, the Golf GT can be recognised by its modified front section that is similar to the GTI whilst nevertheless retaining its individuality. For example, the V-shape is developed but is much more understated than in the GTI. Further special optical cues include the GT logos on the front and fear as well as special alloy wheels and the visible twin tailpipe. The standard equipment of the Golf GT is based on the Trendline and includes electric front windows, electrically adjustable and heated outside mirrors, central locking with radio remote control, six airbags, headrests and three-point seat belts for all five seats, electromechanical power steering as well as ABS with electronic stability programme (ESP) and traction control (ASR).
The dynamically set-up Golf GT, whose two available 170 PS power plants enable it to achieve excellent performance, has a sports chassis lowered by 15 millimetres, 17-inch alloy wheels in the “BBSClassiX” design with 225/45 R17 tyres. The 16-inch brakes (as in the Golf GTI) combined with the brake assistant ensure that the Golf GT, both in the guise of the compressor-turbo and the most powerful TDI in the compact class, can be reined in safely.
In the interior, the Golf GT will appeal with special sports seats in the individual “Brick” design, a three-spoke leather steering wheel with GT logo and a boost pressure display in the cockpit (TSI).
Twin-turbocharged FSI engines - Central aspects
Wolfsburg, 29 August 2005 - At the International Motor Show (Cars) in Frankfurt, Volkswagen is presenting to the general public a ground-breaking innovation in the drive sector: The world’s first twin-turbocharged FSI engine – the “Twincharger”. The compact 1.4 litre direct-injection engine develops up to 125 kW / 170 PS and has a maximum torque of 240 newton metres in the range from 1750 to 4500 rpm thanks to the combination of an exhaust turbocharger with a mechanically driven compressor.
The 1.4 litre engine delivers a power output of 90 kW / 121 PS per litre, representing a peak value for a series production four-cylinder engine. Furthermore, the “Twincharger” delivers a torque corresponding to a naturally aspirated engine with a swept volume of approx. 2.3 litres. And its fuel consumption is around 20 percent lower.
Another performance variant of this innovative TSI engine with 103 kW / 140 PS (maximum torque 220 newton metres) will be available from early 2006, initially in the Touran compact MPV, and after that the Golf will also be available with this engine.
THE TASK
Reducing consumption values – Increasing driving performance
It is the declared objective of European car makers to reduce CO2 emissions. This will be done in various steps, to a value of 140 grams per kilometre. Reduction in CO2 emissions goes hand-in-hand with a reduction in fuel consumption. Achieving this ambitious target will require a combination of the latest engine technology with driveline optimisation.
However, this is not enough. As well as the consumption reduction, it was specified that there had to be a full torque characteristic combined with a high standard of quality and a long service life. In addition, the engine had to be compact to allow it to be integrated into many different vehicle concepts. And, it would have to be designed to enable straightforward production in high quantities. Another target was concerned with resolving numerous conflicting objectives in an innovative way. To cut a long story short – we succeeded.
THE CONCEPTUAL IDEA
A compact FSI engine with twin, different supercharging as an approach to the solution
The most effective way to reduce consumption is referred to as downsizing. A reduction in cubic capacity and therefore lower friction losses result in a low specific consumption, which equates to better efficiency. However, an engine with a low cubic capacity only meets the current requirements for active road safety and pleasurable driving to a very limited extent. As a result, the objective can only be achieved by supercharging. Classic turbo engines with a small cubic capacity supercharged using exhaust turbochargers have only been used to a very limited extend in the past since they have low moving-off power and are therefore less acceptable. This problem can be solved by a mechanically driven supercharger that supplies additional fresh air to the engine even at low speeds. The challenge was to combine these two systems in a rational way.
The only candidate for injection technology was the FSI technology that is now used by Volkswagen in numerous model ranges. Experience gathered during the last few years by engine developers at Volkswagen in this injection technology had revealed that FSI could be ideally complemented by the two different supercharging techniques, the result being a previously unheard of increase in efficiency.
This gave rise to the world’s first direct-injection SI engine with twin supercharging for use in high-volume series production – the “Twincharger”.
THE IMPLEMENTATION
Compressor for power at low speeds, turbocharger for power at high speeds
The choice for the basic power unit was the FSI from the EA 111 engine series as used in the Golf in power levels of 66 kW / 90 PS (1.4-litre) or 85 kW / 115 PS (1.6-litre). The 1.4-litre engine is a four-valve four-cylinder engine with a swept volume of 1390 c.c., a cylinder gap of 82 millimetres and a bore/stroke ratio of 76.5 to 75.6 millimetres. The focus in developing the “Twincharger” engine was placed on designing a new, highly resilient grey cast iron cylinder crankcase in order to withstand the high pressure of up to 21.7 bar over long periods, a water pump with integrated magnetic clutch and supercharging technology.
However, the injection technology was also modified. A multiple-hole high-pressure injection valve with six fuel outlet elements is used for the first time in the 1.4 l TSI engine. The injector, like that in the naturally aspirated FSI engines, is arranged on the intake side between the intake port and cylinder head seal level. The quantity of fuel to be injected between idling speed and the 90 kW/litre output power requires a wide variability in the fuel flow through the injectors – given a sufficient mixture preparation time after completion of injection under full-load conditions on the one hand and idling speed with reproducibly low injection volumes on the other hand. The maximum injection pressure was increased to 150 bar in order to achieve this wide range of throughflow. Furthermore, only FSI technology made it possible to achieve a compression ratio of 10:1 which is high for supercharged engines.
The Volkswagen engine developers selected a compressor with a mechanical belt drive in order to increase the torque at low engine speeds. This is a supercharger unit based on the Roots principle. One special feature of the compressor used is its internal step-down ratio on the input end of the synchronisation gear pair.
The exhaust turbocharger also kicks in at higher engine speeds (with wastegate control). The compressor and exhaust turbocharger are connected in series in this case. The compressor is operated by a magnetic clutch integrated in a module inside the water pump. A control flap ensures that the fresh air required for the operating point can get through to the exhaust turbocharger or the compressor. The control flap is open when the exhaust turbocharger is operating alone. In this case, the air follows the normal path as in conventional turbo engines, via the front charge-air cooler and the throttle valve into the induction manifold.
One of the major challenges facing the development was to achieve the best possible interplay between the two superchargers arranged in series. Only when both units – the compressor and the exhaust turbocharger – complement one another optimally can the small power unit achieve its required, level torque characteristic over a broad engine speed range in conjunction with a previously unheard of increase in efficiency.
THE RESULT
A twin-turbocharged FSI with two power levels
The ambitious objective of squeezing an output per litre in excess of 90 kW per litre swept volume out of a 1400 c.c. engine could not be achieved with single-stage supercharging alone. However, an upstream compressor enables the boost pressure buildup of the exhaust turbocharger to be significantly increased.
The maximum boost pressure of the “Twincharger” is approx. 2.5 bar at 1500 rpm, with the exhaust turbocharger and the mechanical supercharger being operated with about the same pressure ratio (approx. 1.53). A straight exhaust turbocharged engine without compressor assistance would only achieve a pressure ratio of about 1.3 bar here. The more rapid response of the exhaust turbocharger enables the compressor to be depressurised earlier by continuous opening of the bypass valve. This means compressor operation is restricted to a narrow map area with predominantly low pressure ratios and, therefore, low power consumption. Consequently, the disadvantage of the mechanical supercharger system in terms of consumption can be limited.
In practice, this means the compressor is only required for generating the required boost pressure in the engine speed range up to 2400 rpm. The exhaust turbocharger is designed for optimum efficiency in the upper power range and provides adequate boost pressure even in the medium speed range. In dynamic driving, this is inadequate for the specified in-gear acceleration values in the low engine speed range. In these driving situations, the compressor is engaged to permit a spontaneous boost pressure buildup. The way in which these two systems complement each other means there is absolutely no turbo lag. The compressor is no longer needed above an engine speed of 3500 rpm at most, as the exhaust turbocharger can definitely provide the necessary boost pressure even dynamically during the transition from coasting to full-load operation.
THE DRIVING EXPERIENCE
High performance and torque produce low consumption and enormous driving pleasure
The compressor, with its high ratio of 1:5 in relation to the crankshaft, delivers a boost pressure of 1.8 bar even just above idling speed. This provides the power needed when moving off. An electromagnetic clutch integrated in the module of the coolant pump is responsible for switching the compressor on and off. It is driven by an additional belt. A torque of 200 newton metres is available at a speed of only 1250 rpm – and all the way through to 6000 rpm. In dynamic compressor mode, the automatic boost pressure control decides whether the compressor will be switched on in accordance with the tractive power required, or if the turbocharger alone can generate the necessary boost pressure. The compressor is switched on again if the speed drops to the lower range and then power is demanded again. The turbocharger alone delivers adequate boost pressure above 3500 rpm.
In practice, the “1400 Twincharger” drives like a big naturally aspirated engine with 2.3-litre cubic capacity. This is because the maximum torque of 240 newton meters is available from 1750 rpm to 4500 rpm. The boost pressure gauge installed as standard in the cockpit of the Golf GT 1.4 TSI is the only signal of the furious activity being undertaken by the superchargers and the complex procedure of harmonizing both systems taking place under the engine hood. The driver likes it, because when the needle is fully deflected then the acceleration really presses the occupants back into their sports seats (fitted as standard).
[IMG]Power/torque characteristic of 1.4 TSI 125 kW[/IMG]
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