New BMW M3 Coupe (E92)

New BMW M3 Coupe (E92) - In Depth

标签： BMW 0 评论

Page 1: Short story
Page 2: Concept
Page 3: Power unit
Page 4: Chassis & suspension
Page 5: Design
Page 6: Body
Page 7: Safety
Page 8: Features
Page 9: Production

Power Unit

The Thrill of a V8 – Muscle Machine with an Ideal Body

Debut: eight-cylinder power unit displacing 3,999 cc and developing 309 kW/420 hp.
Brake Energy Regeneration: more power on less fuel.
High-tech carried over from motorsport: high-speed engine concept, double-VANOS, individual throttle butterflies, wet sump lubrication optimised for dynamic motoring, ion flow technology.

An exceptional engine for an exceptional sports car: The V8 power unit featured in the new BMW M3 raises the standard of driving pleasure offered by this high-performance two-door from BMW M GmbH to an unprecedented dimension, thus providing a thrilling and convincing answer to the question frequently asked by genuine aficionados of genuine sports cars whether further improvement of this unique car was still possible at all.

For after 15 years and two complete model generations, the epoch-making six-cylinder lauded several times over as the “Engine of the Year” and developing maximum output in its final version of 252 kW/343 hp has found its successor.

The eight-cylinder power unit in the new BMW M3 offers more cylinders, greater engine size, more power, and higher engine speeds – which, in practice, means ever greater thrill of motoring right from the start. Indeed, the combination of this power unit and the unique concept of the new BMW M3 is truly fascinating in every respect.

The specifications of the new high-performance engine alone clearly confirm the enormous progress this changeover to a new engine has to offer:
Engine capacity is 3,999 cc, maximum output 309 kW/420 hp at 8,300 rpm. Maximum torque of 400 Newton-metres/295 lb-ft is just as impressive as the top engine speed of 8,400 rpm.

Benefiting from this kind of power, the new BMW M3 literally rockets to the forefront right from the start, accelerating to 100 km/h in just 4.8 seconds and continuing to push ahead with all its power until the electronic control unit limits the top speed of this two-door sports car to 250 km/h or 155 mph.

Apart from this supreme performance and specific output of 105 hp per litre, average fuel consumption of just 12.4 litres/100 km in the EU test cycle (equal to 22.8 mpg imp) bears clear testimony to the engineering skill of the power unit specialists at BMW M GmbH.

Ideal dimensions for optimum performance.

Displacing 500 cc per cylinder, the new V8 power unit from the start comes with ideal engine dimensions just right for supremacy in technology, on road and track. And while a similarly powerful six-cylinder would simply not have had these ideal dimensions just right on a sports engine, the new V8 offers the very best in both theoretical and practical terms through its dimensions,
filling capacities, the number of components and the weight of the engine.

At the same time the new eight-cylinder naturally comes with the specific features of BMW M such as double-VANOS, individual throttle butterflies and high-performance engine electronics. The number of cylinders, the M high-speed engine concept, and the low weight of the engine also prove quite clearly that the engineers at BMW M GmbH were inspired from the start by the eight-cylinder powering the BMW Sauber Formula 1.

Indeed, the new engine has many features in common with the latest power unit by BMW Sauber in Formula 1, sharing a number of principles in technology, production methods and materials all carried over from Formula 1 to the new BMW M3.

One important difference, however, will always remain: The BMW M3 is not pushed to the limit only occasionally on a racing weekend. Instead, its high-performance engine runs smoothly and reliably every day, on all roads and in all kinds of weather – and this it does for years of consistent motoring.

High-speed engine concept for unparalleled thrust.

In its specific output, the new V8 significantly exceeds the mark of 100 hp per litre acknowledged as the decisive benchmark for particularly sporting and dynamic performance. But even so, power is not everything, since the experience of genuine driving dynamics depends to a large extent on the car’s acceleration which, in turn, is largely influenced by the weight of the car and the thrust of the engine.

The thrust and power going to the drive wheels, in turn, is a function of engine torque and the overall transmission ratio. And it is precisely here that the M high-speed engine concept allows optimum gear and final drive ratios setting the basis in practice for truly amazing power and performance on the road.

Using these qualities, the engine development specialists at BMW M ensure that the spontaneity offered by the engine with its immediate response to the driver’s commands fulfils all the demands made of a genuine M Car. So in its power potential, the way it offers superior torque and performance, in its dimensions and weight, the new V8 is most definitely a typical BMW M engine.

Focusing on the new BMW M3, the engineers at BMW M have raised the high-speed engine principle to a new dimension. Maximum engine speed is 8,400 rpm, maximum torque – the second factor crucial to the car’s thrust and performance – is 400 Newton-metres or 295 lb-ft at 3,900 rpm.

A further significant point is that some 85 per cent of this maximum torque is available consistently throughout a huge speed range of 6,500 rpm, with no less than 340 Newton-metres or 251 lb-ft cutting in at just 2,000 rpm.

This clearly comes to bear in the performance and character of the new BMW M3 offering not only extremely dynamic driving characteristics but also all the fortes required for fast cruising on winding country roads or in city traffic.

High performance, low weight.

Weighing just 202 kilos or 445 lb, the new V8 is a genuine lightweight. In fact, it is approximately 15 kilos or 33 lb lighter than the six-cylinder in the former model, meaning that the lightweight technologies used on the engine easily set off the weight of the two extra cylinders. And a further point is that, through its design principle alone, the high-speed engine concept keeps the drivetrain light and allows very short gear ratios.

The fact nevertheless remains that increasing engine speeds bring the limits of extreme physics closer and closer: At an engine speed of 8,300 rpm – the speed at which the engine develops its maximum output of 309 kW/420 hp – each of the eight pistons covers a distance of no less than 20 metres or 66 feet, obviously with enormous loads acting on the materials and components. So for this reason alone, the engineers creating the new eight-cylinder attached maximum value to minimum moving masses right from the start.

Engine block straight from BMW’s Formula 1 foundry.

The engine block of the new eight-cylinder comes from BMW’s light-alloy foundry in Landshut north of Munich, which also builds the engine blocks for the BMW Sauber Formula 1 racing cars.

The new V8 is made up of two rows of four cylinders in a V-angle of 90° and with the two rows offset from one another by 17 millimetres or 0.67´´ to make the engine very compact. Piston stroke is 75.2 millimetres or 2.96´´ and bore is 92 millimetres or 3.62´´, adding up to a total capacity of 3,999 cc.

The crankcase is made of a special aluminium-silicon alloy, the cylinder liners being formed by exposing the hard silicon crystals, instead of using conventional liner sleeves. The iron-coated pistons therefore run directly in these uncoated, honed bores.

With high engine speeds and combustion pressure obviously causing tremendous loads on the crankcase, the entire crankcase unit is a particularly compact and torsionally stiff bedplate structure also in the interest of very precise crankshaft bearing. The relatively short, forged crankshaft, in turn, is likewise very stiff in terms of both flexural and torsional forces, but still weighs only about 20 kg or 44 lb.

Compared with conventional systems, the crossflow cooling concept featured on the new V8 significantly reduces pressure losses in the cooling system, spreading out temperatures smoothly within the cylinder head and thus reducing peak temperatures at all critical points. To ensure an optimum flow of coolant around each cylinder, the cooling liquid comes into the crankcase from the exhaust side, flowing crosswise through the cylinder head and above the collector rail on the intake side back to the thermostat and, respectively, the radiator.

Valve management by double-VANOS operating at engine oil pressure.

Keeping valve timing extremely quick and short, variable double-VANOS camshaft adjustment optimises the response of the engine, reducing charge cycle losses and thus improving engine power, torque, fuel economy and emission management all at the same time.

Low-pressure M double-VANOS developed especially for the new eight-cylinder just requires normal engine oil pressure to keep valve timing extremely short and fast. The electronic engine “brain”, in turn, sets the optimum spread angle to precisely the right ignition timing and injection volume as a function of load and engine speed.

Reliable oil supply even under extremely dynamic driving conditions.

Being a very dynamic car capable of high speeds in virtually every situation, the BMW M3 requires a sophisticated, high-tech system to supply lubricant to the power unit. Accordingly, the engine lubrication system is able to operate without problems under straight-ahead and lateral acceleration of up to 1.4 times the normal g-forces of the earth, a volume flow-controlled pendulum-slide vane pump delivering lubricant reliably to the eight-cylinder at all times – that is precisely the amount the engine requires.

Wet sump lubrication optimised for a supreme level of driving dynamics ensures reliable lubrication even when applying the brakes under extreme conditions. The oil supply system features two oil sumps – a small one upfront of the front axle carrier and a large oil sump behind the axle. A separate reflow pump extracts oil from the front oil sump and pumps it to the rear.

Eight single throttle butterflies masterminded electronically.

Separate butterflies for each cylinder are the perfect solution not only in motorsport to ensure an immediate engine response at all times. So this is precisely why the new power unit of the BMW M3 features eight individual throttle butterflies, one for each cylinder.

Two actuators each control four throttle butterflies on each row of cylinders in a fully-electronic and ultra-fast process. This ensures sensitive response of the engine throughout the entire speed range and an immediate reaction of the car in response to the gas pedal, even when the driver requires maximum power.

Flow-optimised air intake.

To ensure spontaneous, dynamic performance of the engine, the throttle butterflies in the intake manifolds are positioned very close to the intake valves. The entire intake air flow within the eight-cylinder power unit no longer requires the conventional sensors incorporated in a hot film air mass flow meter, with engine load being determined instead by the electronic engine control unit – a significant advantage, since such conventional sensors are relatively complex and involve disadvantages in the geometric configuration of the air flow.

To determine load conditions in the engine, the control unit calculates the current load by taking the positions of the throttle butterfly and idle speed adjuster, the position of double-VANOS valve control, engine speed, air temperature and air pressure as the essential parameters. This gives the engineers new options and freedom in designing and optimising the engine air intake, and a further advantage is that this modern control concept offers maximum reliability at all times.

The charge effect generated in the oscillating tube is enhanced by the length and diameter of the intake funnels, the funnels themselves and the air collector being made of a light composite material with a 30 per cent share of glass fibre in order to reduce weight to a minimum.

Innovative exhaust system.

Through its design and configuration, the exhaust system on the new V8 power unit optimises the charge cycle in the interest of maximum power and torque. Here again, the entire exhaust system is also designed and built for minimum weight, using the latest lightweight technology.

The exhaust pipes are made in an inner high-pressure moulding process, with the contours required on the stainless-steel pipes being shaped from inside under pressure of up to 800 bar. This method serves to provide pipes with extremely thin walls measuring only 0.65–1.0 millimetres in thickness, minimising flow resistance and weight, and optimising the response of the catalytic converters.

The exhaust gas is cleaned efficiently by four catalytic converters,
ensuring that the engine fulfils the European EU4 standard as well as the US LEV 2 classification.

Noise emissions are also reduced to a sensible level, particularly the single-piece rear-end muffler with its very large volume of 35 litres serving to reduce the noise level, over and above the two intermediate silencers.

It almost goes without saying, however, that the new V8 power unit featured in the BMW M3 retains its exceptional sound and character, the eight-cylinder naturally offering a throaty sound typical of BMW M and reminiscent of motorsport.

Offering an even higher standard of performance: the engine control unit.

The electronic control unit masterminding all functions of the V8 in the new BMW M3 is also a new development achieving an even higher standard than before. Taking more than 50 incoming signals, for example, the engine control unit determines the optimum ignition timing, the ideal cylinder charge, precisely the right injection volume and the accurate injection timing individually for each cylinder. At the same time, that is in a synchronised process, it calculates and sets the optimum camshaft spread and sets the eight individual throttle butterflies to precisely the right position.
And as a further important factor, the control unit also supports the M-specific functions of the clutch, transmission, steering, and brakes.

Last but not least, the electronic engine “brain” performs a wide range of on-board diagnostic functions with various diagnostic routines for the workshop as well as further functions and all-round management of various peripheral units and components.

An absolute highlight in engine management: ion flow technology.

A particularly highlight in engine management is ion flow technology serving to detect engine knocking as well as misfiring and miscombustion.

Contrary to conventional procedures, this precise detection function is exercised exactly on the spot, that is in the combustion chamber.
This is done by sensing any possible knocking effect via the spark plug in each cylinder, with appropriate control of ignition timing.

The combustion process is also controlled at the same time, with the system detecting any misfiring or miscombustion. The spark plug therefore serves as an actuator for the ignition and as a sensor observing the combustion process.

The engine’s electronic control unit then distinguishes between miscombustion and misfiring in a double function facilitating the diagnostic routine in engine maintenance and service.

Brake Energy Regeneration for enhanced efficiency and driving dynamics.

To enhance the efficiency of the entire drivetrain to an even higher standard, Brake Energy Regeneration, a new, intelligent energy management concept, concentrates the generation of electrical energy for the car’s on-board network exclusively on periods when the car is in overrun or when the driver is applying the brakes. This serves to charge the car’s battery without resorting to engine power and, accordingly, to the energy contained in the fuel consumed.

Generally, therefore, the alternator is disconnected and not in use while the engine is pulling the car in the traction mode.

Apart from particularly efficient generation of electrical energy, this also helps to improve the car’s acceleration and power and ensures an even higher standard of driving dynamics.

With the number of charge cycles increasing on account of this intelligent management of the power generation process, Brake Energy Regeneration is combined with modern AGM Absorbent Glass Mat batteries able to handle far greater loads and tougher conditions than a conventional lead-acid battery. The particular advantage of an AGM battery is that it retains the acid required in microglass fibre mats between the individual layers of lead, thus ensuring long-term storage of energy even when charged and discharged frequently in the course of the battery’s life.