BMW Biturbo Petrol Inline Six Engine In Depth

Press Release

Page 1: Efficient Dynamics (I)
Page 2: Efficient Dynamics (II)
Page 3: Turbocharged Power
Page 4: Fuel Economy
Page 5: Automatic Transmission
Page 6: Alternator Control
Page 7: Engine Construction
Page 8: Specifications

Consistent Progress for Efficient Dynamics.

The overall framework for developing innovative technologies of the type described is set by the lawmaker while the actual process of implementation is determined by the customer. But still, engine development at BMW is influenced only indirectly by external factors, since the Company's fundamental urge in striving for new innovations time and again follows from the self-perception of the BMW brand, the competence in technology of the BMW Group, and the demands thus made of BMW products.

"Sheer Driving Pleasure" is the motivation underlying not only the customer's expectations, but also the demands made of BMW's engineers. But driving pleasure these days is a function not only of superior dynamics, but also of enhanced efficiency. A conscious experience of Sheer Driving Pleasure therefore also means the knowledge of not having to pay for extra dynamics by way of excessive fuel consumption.

Precisely this is why the BMW Group has established the general development target of EfficientDynamics with very clear standards and criteria. And with each new generation of engines providing the qualities for even better performance, each new power unit also serves to enhance all-round economy to an even higher standard.

BMW already sets the standard in EfficientDynamics today through the gasoline and diesel engines the Company offers to the market. These power units are the result of a consistent process of development with an equal focus on enhanced performance and the optimisation of fuel consumption. The drive units featured in the BMW Group's current models also offer the potential to achieve further progress in future in both areas, with innovations in technology resting on and supplementing one another.

More power, comfort, and safety but on less fuel.

A comparison of engine concepts from former decades with the power units offered to the customer today clearly confirms the progress achieved: Looking at a BMW 323i in the 1983 model year versus the current BMW 325i both of these models featuring a straight-six power unit we immediately see the substantial difference: Engine output is up by 57, maximum torque by 24 per cent. Acceleration, in turn, has improved by 24 per cent. And while vehicle weight is up by 38 per cent, the drag coefficient is 16 per cent lower. Fuel consumption is now 20 per cent below the figure in 1983, and emission management has improved by no less than 95 per cent.

These figures alone confirm the great extent to which progress is committed to the overriding objective of EfficientDynamics. A modern car offers more space, more comfort, and more safety. Hence, it is larger and heavier than former models in the same segment. But the larger frontal area has been more than set off by improvements in aerodynamics, while the use of modern materials has been able to keep the increase in weight within limits, without however setting off this increase completely.

With fuel consumption not increasing under these circumstances, but quite on the contrary decreasing most significantly, we see and learn to appreciate the very substantial improvement in efficiency offered by a modern power unit. Benefiting from lower friction, optimised combustion and a more efficient charge cycle, a modern power unit offers significantly greater dynamics and a very noticeable decrease in fuel consumption. Further efficiency is added by new transmissions with a larger number of gears and, as a result, an optimised spread of gear ratios.

This reduction of fuel consumption is accompanied by a significant decrease in emissions. Indeed, elaborate and sophisticated management of exhaust emissions ensures full compliance with legal standards and limitations now allowing only a fraction of the emission levels permitted in former times.

Innovations with a lasting effect.

BMW has set numerous milestones in the course of this development history clearly marked out by the above comparison: Proceeding from four-valve technology via variable VANOS valve management and double-VANOS all the way to fully variable VALVETRONIC valve management, BMW has presented outstanding innovations time and again. And in each case these innovations have served to reduce fuel consumption and emissions, while consistently increasing engine output and performance.

These innovative systems have many features in common: They are used in engines of various size, configuration and design. They supplement one another and provide the effect desired also in everyday traffic. And therefore they are never just short-term, fleeting solutions. On the contrary four-valve technology is now state-of-the-art in a whole range of drive units, VANOS and VALVETRONIC are featured in engines with a various number of cylinders and will play a major role also in engines of the future.

Following a clear BMW principle, all new developments must fulfil their function consistently and with sustainable effect. On the diesel engine, direct fuel injection is already meeting this demand in the third generation. And now BMW offers a technology of this kind leading the way in the gasoline engine towards a genuine, significant reduction of fuel consumption: High Precision Fuel Injection now being presented by BMW as the second generation of direct gasoline injection ensures a supreme standard of all-round flexibility. This technology is featured in the new, particularly powerful and dynamic Twin-Turbo straight-six, and may also be operated as lean-burn direct fuel injection.

Contrary to the first generation of direct gasoline injection, which failed to offer the aspired improvement of fuel economy in everyday traffic and was therefore not taken up by BMW, High Precision Fuel Injection makes a significant contribution to EfficientDynamics in every respect.

Energy flow management on two levels.

In addition to this breakthrough technology, BMW is also pursuing a strategy of intelligent energy flow management throughout the Company's entire range of engines, a strategy benefiting all engines regardless of size, configuration, and technical specifications.

In this case the loss of energy is avoided from the start on two levels: Automatic engine start/stop serves to prevent the loss of primary energy and is activated whenever the engine is idling. The automatic start/stop technology used by BMW switches off the drive unit for example when stopping at traffic light. Then, to start the engine again, all the driver has to do is press the clutch pedal. Provisional calculations based on the EU test cycle show that this function alone is able to reduce the average fuel consumption of a BMW 3 Series by up to 0.5 litres/100 kilometres.

The second level of energy flow management focuses on the generation, storage and use of electric energy on board the vehicle. Electric energy is required to operate numerous comfort, safety, and dynamic functions. Intelligent Alternator Control developed by BMW serves to shift the conversion of primary energy into electric power entirely into the overrun and braking phases, thus providing more engine power for the generation of kinetic energy during the real power phases with the engine actually "pulling" the car. A further point is that the regeneration of brake energy allows the use of additional reserves previously remaining untapped and unused.

Applying this concept referred to as Brake Energy Regeneration, BMW converts energy previously escaping unused as thermal energy from the brake discs into electric power, thus generating additional energy for the on-board network every time the driver applies the brakes.

Depending on driving conditions and the current mode of engine operation, such a managed or masterminded flow of energy serves to provide enhanced dynamics and efficiency in converting fuel into motion, heat and electrical energy.

The technology required for this purpose is on the verge to reaching production standard at BMW. And since these systems may be used in engines of various configuration and size, a large number of customers is able to benefit from their advantages, once again enjoying even better dynamics on even less fuel.

This wide range of potential benefits and practical use is of great significance to BMW also for another reason, since such a diversity of technologies serves to minimise fleet consumption and exhaust emissions in order to reach the strictest requirements and standards without impairing Sheer Driving Pleasure at the wheel.