The most economical and lowest emissions Golf of all times is one of the highlights at Volkswagen's IAA exhibition area this year in Frankfurt. The new Golf BlueMotion consumes just 4.5 liters of diesel per 100 kilometers - compared to the already very economical predecessor model this represents a significant improvement of 0.6 liter. With that, this bestseller that defies class categorization breaks the five liter fuel economy barrier, which has been very difficult to achieve in large-scale production vehicles in its segment until now. At the same time, CO2 emissions are decreased from 135 g/km to 119 g/km. The convincing environmental benefits of this especially modest Golf go hand in hand with its unchanged agile temperament, further improved noise comfort and good driving performance. Its top speed rose from 187 km/h to 190 km/h (electronically limited), while its acceleration to 100 km/h remained practically unchanged at 11.3 seconds.
BlueMotion in the case of the Golf means this, first and foremost: Clever detail modifications to the body, a fuel economy optimized direct-injection turbo-diesel with diesel particulate filter, modified ratios of the five-speed gearbox and special tires with reduced rolling resistance. Measures that in their sum total have a positive effect on the car's range too. On just one 55 liter tank of fuel the Golf BlueMotion travels more than 1,200 kilometers. At an annual driving distance of 12,600 kilometers that is typical of this class, this corresponds to just over one gas station stop per month.
ENGINE AND TRANSMISSIONS
The Golf BlueMotion calls upon the engine of conventional Golf versions that is known to be efficient, and it shares its specification data: 1.9 liter displacement, 77 kW / 105 PS and a maximum torque of 250 Nm (from 1,900 rpm). To attain these very ambitious fuel economy goals, the specialists at Volkswagen further exploited the innovative potential of TDI direct-injection technology.
One example: thanks to a specific software modification to its engine management, it was possible to reduce idling speed from 830 to 730 rpm. Important parameters such as charge pressure, injection point and exhaust gas recirculation rate were further optimized in the pursuit of the lowest possible fuel consumption.
Affecting fuel economy just as positively is the speed-reducing layout of the five-speed transmission. While the gear ratio for third gear was lengthened by 7.9 percent, other gears were lengthened even more: Fourth (+ 14.6 percent) and fifth (+ 19 percent). The effect: These modifications alone improve average consumption by about 0.2 liters per 100 kilometers. A pleasant additional benefit: A reduction in engine speed level improves noise comfort. The car's acceleration temperament, which is important in everyday traffic, retains its crispness thanks to the engine's powerful torque characteristic and unchanged ratio of the first two gears.
However, the greatest influence on a car's fuel economy is exerted by the driver. Here too the engine management system of the Golf BlueMotion offers important assistance: The ECU outputs a gear shift recommendation via the standard Multifunctional Display Plus (MFA Plus) depending on the driving situation and indicates which of the five forward gears is currently the most efficient.
Besides the efficiency of engine and transmission, air resistance is also very crucial when it comes to fuel economy. The greater the car speed, the greater its significance. As on the Polo BlueMotion, Passat BlueMotion and Passat Variant BlueMotion, on the Golf BlueMotion Volkswagen developers also succeeded in optimizing the aerodynamic advantages of the body by specific refinements. The results: The air drag coefficient was reduced by 6.3 percent from the already good initial value of cW 0.32 to 0.30 - an exceptionally good result for the compact class, which also contributes to the increase in top speed from 187 to 190 km/h (electronically limited).
This most prominent visual action: The completely enclosed radiator grille that offers fewer points for the driving wind to take hold. To ensure that the engine of the Golf BlueMotion does not become too hot, the 4.5 liter car automatically gets a dual air fan; this fan is otherwise only offered in combination with a trailer hitch or delivery to a so-called "hot country" - extremely warm climate zones.
All other aerodynamic modifications act behind the scenes. Example: Underbody. Special covers for the brake line conduits and trim in front of the rear axle quiet the air stream beneath the Golf BlueMotion and thereby reduce air resistance. Serving the same purpose is the standard sports chassis that lowers the body of the bestseller by ten millimeters.
The fuel economy and emissions advantages of the Golf BlueMotion are the result of an entire bundle of different detail modifications that also involve the chassis and tires. Besides the already described production sports chassis that makes for a lower profile by ten millimeters, this savings master also benefits from special high-tech tires with significantly reduced rolling resistance. The Golf BlueMotion stands on 15 inch wheels and 195 / 65 low profile tires. They are driven at air pressures elevated by 0.3 bar and are rated for a top speed of up to 190 km/h (Speed index "T").
As a new option, besides the option of combining the new BlueMotion cars with the first three models - they may also be combined with classic equipment lines. The BlueMotion specifications add to the features of the particular equipment line. This much is clear: When adjustments are made for equipment options, a Golf BlueMotion hardly costs any more than a comparable 105 PS TDI in a classic line.