Two figures alone would seem to say it all about the Bentley Continental GT: it accelerates from 0-60mph in 4.7sec (0-100km/h 4.8sec) and reaches a top speed of 198mph (318km/h). In fact such bold statistics barely scratch the surface of the Bentley Continental GT's true capabilities.
The aim from the start of the Bentley Continental GT project was to create a car with an unrivalled performance envelope, so that it would not only be quicker and more powerful than any rival on paper, but that these extraordinary talents would also be able to be used safely and to the full in the real world. The Bentley Continental GT is not and never was about theoretical performance potential - every aspect of its ability has been specifically tailored so that it is not just possible to access its performance, it is easy and natural.
Moreover, the Bentley Continental GT concept also dictated that the resulting car would recognise that, though we would all wish otherwise, road conditions in all markets mean that frequently its owners will not be able to make use of its full potential. Indeed in some regions traffic conditions are such that being able to extend such a car is more of a rare treat than an everyday occurrence. Which is why in addition to being able to thrill its occupants at a moment's notice, the Bentley Continental GT is also configured to comfort and cosset them the rest of the time - in the tradition of a true British Grand Tourer.
The Bentley Continental GT is the first product designed entirely under the patronage of the Volkswagen Group and a £500 million investment in the marque has enabled a transformation of the site at Crewe. This made it possible for the Bentley Continental GT to be designed, engineered and assembled on site.
The investment has also made it possible for Bentley to recruit over 400 new staff to Crewe, giving Bentley greater independence and control over its future than at any time since it first passed into proprietary ownership in 1931.
Engine
The heart of the Bentley Continental GT is its 5998cc, four camshaft, 48-valve, twin turbocharged W12 engine. It can now be revealed that its power output, hitherto quoted as 'in excess of 500bhp', is in fact 552bhp (560PS) (411kW) at 6100rpm. Maximum torque is 650Nm (479lb ft) which may sound an impressive enough statistic in isolation but its true significance only become apparent when you learn that it is generated at just 1600rpm. Typically, a performance car engine will force the driver to wait until it is spinning at between 3-5000rpm before it will deliver maximum thrust; in the Bentley Continental GT it's all there at barely more than idling speed. No other car in production makes its torque so instantly accessible.
But this just the start of the story for this engine has other claims to fame beyond its headline-grabbing outputs. Its exterior dimensions, for instance, make it the smallest 12-cylinder engine currently in production, despite its considerable 6-litre displacement. The block is just 513mm long, 715mm high and 710mm wide. This has been made possible entirely by its 'W' formation where instead of arranging the cylinders in two long rows as you would in a conventional V12 configuration, each bank of cylinders is actually staggered, effectively creating two V6 engines mated on a common crankshaft. The angle between the two main banks is 72deg, that between the staggered cylinders just 15deg. The result of this is an exceptionally compact motor, a trait that brings advantages in many areas. Clearly it helps hugely with weight distribution as a geographically small engine is easier to locate nearer the centre of the car. This in turn helps the overall packaging of the car and, in particular, its frontal crash performance, a crucial consideration in a Bentley which has a short front overhang as one of the main features of its design language.
It is no secret that the basic engine architecture has been supplied to Bentley from its parent company, the Volkswagen Group, but by the time Bentley's powertrain team had finished re-engineering it to an exclusive specification for the Bentley Continental GT, it could be truly considered a unique engine in its own right.
Clearly the major engineering challenge was to adapt the engine to accept forced induction, a process that required major re-engineering of the block, the replacement of many internal components and all new inlet and exhaust manifolds. The result would have to cope with a rise in output from 420bhp in standard form to 552bhp once installed under the bonnet of the Bentley Continental GT.
The engine features special pistons, specifically designed for the Bentley Continental GT in order to deliver the desired compression ratio of 9.5:1, a phenomenally high figure for a turbocharged engine. The engine also features seven main bearings, pent-roof combustion chambers and variable valve timing on both inlet and exhaust valves. The timing is infinitely variable within its fixed range, which is some 52 degrees on the inlet camshafts and 22 degrees on the exhaust camshafts.
A huge amount of work was also undertaken to make sure the Bentley Continental GT could use very efficient air to air intercooler. Fitting them within the already cosy confines under the Bentley Continental GT's bonnet was not the matter of the moment, but Bentley's engineers regarded their inclusion in the specification as not negotiable and, after several months work, they were integrated into the under bonnet package.
The Bentley Continental GT also uses a dedicated exhaust system, using two six-into-one manifolds. Much attention has been paid not simply to ensure the exhaust provides maximum efficiency, but also that its sound is appropriate to the fastest Bentley road car in both tone and volume.
The turbochargers are made for Bentley by renowned specialists, KKK, and need operate at only the comparatively conservative boost pressure of 0.7bar to provide the Bentley Continental GT with its headline performance. Given this, the existence of maximum torque at 1600rpm and the engine's 6-litre capacity and it's easy to see how turbo-lag, the sole undesirable side-effect of this variety of forced induction, has been effectively removed from the equation. As with all Bentley-designed powerplants since the birth of the company in 1919, smooth power is not something you need to wait or ask for - it is there, at your disposal at every point of the rev-range from idle to its 6100rpm red-line.
Controlling all this power is Bosch's state of the art ME 7.1.1 engine management system which comes complete with two throttle bodies, exhaust gas temperature regulation, boost pressure regulation, two air mass sensors, four knock sensors with adaptive learning and the latest ESP 5.7 electronic stability programme. Ignition is achieved without the need for a distributor, thanks to each cylinder being provided with its own coil. The engine is fully compliant with future Euro IV emissions regulations and has been calibrated to run on standard 95RON octane pump fuel.
Such is the power of the Bentley Continental GT's powertrain that Bentley engineers took the decision to reinforce its already substantial engine mounts with Kevlar bindings to make sure it does not move even under the most extreme circumstances.
0 comments:
Post a Comment