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1 Series - E82 Coupe (2007 - ...) - Diesel, Turbos and Brake Energy Regeneration

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1 Series - E82 Coupe (2007 - ...)
Exterior Design
Aerodynamics Package, EfficientDynamics and Turbos
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BMW 123d Coupé: offering the best in efficiency and performance.
The new four-cylinder power unit in the BMW 123d Coupé featuring Variable Twin Turbo technology enters new dimensions in terms of output and fuel economy. Displacing 1,995 cc and developing maximum output of 150 kW/204 hp, this is the first all-aluminium diesel in the world to provide output per litre of more than 100 hp. And it is the first diesel in its segment with Variable Twin Turbo technology.
The engine develops its maximum power at 4,400 rpm and delivers its peak torque of 400 Newton-metres/295 lb-ft at just 2,000 rpm.
Offering a top speed of 238 km/h or 148 mph and accelerating to 100 km/h in 7.0 seconds, this superior power unit gives the new BMW 123d Coupé unique performance. At the same time acceleration and performance of this standard combined with average fuel consumption in the EU test cycle of 5.2 litres/100 kilometres (equal to 54.3 mpg imp) are successful results of the BMW EfficientDynamics development strategy. A further important point is that the BMW 123d Coupé, with CO2 emissions of just 138 grams per kilometre, ranks right at the top in its class also in terms of emission management.


Variable Twin Turbo technology featured for the first time in a four-cylinder.
Variable Twin Turbo technology ensures particular efficiency in boosting the power and performance of the engine. Also referred to as multi-stage turbocharging, this technology was previously used only in BMW’s six-cylinder diesel engines and is now featured for the first time in a four-cylinder diesel in the new BMW 1 Series Coupé.
The Variable Twin Turbo system is made up of a small and large exhaust gas turbocharger acting together in feeding intake air to the four cylinders.
Benefiting from its lower inertia, the small turbocharger ensures high torque and pulling power right from the start at speeds just above idling.
At higher speeds the larger turbocharger then cuts in to provide extra power and performance. The big advantage of this configuration is that it provides the desired output and turbocharger effect without the slightest delay.
The 2.0-litre power unit is BMW’s first engine to feature direct-injection common rail technology with the piezo-injectors injecting fuel under the high pressure of 2,000 bar. With the fuel being injected through seven nozzles in up to three “portions” per cylinder, the combustion flame spreads gently during the combustion cycle in the interest above all of motoring refinement and smoothness quite unusual for a diesel.
The combination of dynamic performance and all-round economy which has given the diesel its consistently greater significance, is therefore now raised to a new level in a four-cylinder engine.

Turbocharger with variable turbine geometry in the BMW 120d Coupé.
The power unit in the BMW 120d Coupé comes with one single turbocharger featuring variable turbine geometry to provide a level of power and performance perfectly geared to all load conditions. The blades on the turbine are adjusted by an electric motor with supreme precision to the respective running requirements within fractions of a second, ensuring spontaneous response at low engine speeds as well as high output under full load.
Maximum charge pressure is 2.55 bar and the diesel fuel is fed into the engine by piezo-injectors operating at a pressure of 1,800 bar.
Displacing 1,995 cubic centimetres, the four-cylinder develops a substantial 130 kW/177 hp at 4,000 rpm, with maximum torque of 350 Newton-metres/258 lb-ft between 1,750 and 3,000 rpm. Top speed of the new BMW 120d Coupé is 228 km/h or 141 mph, with acceleration to 100 km/h in 7.6 seconds. At 4.8 litres/100 km, equal to 58.8 mpg imp, fuel consumption is exceptionally low, as is the level of CO2 emissions amounting to just 128 grams per kilometre.
The power units of both the new BMW 123d Coupé and the new BMW 120d Coupé are significantly lighter than comparable four-cylinder diesels, most of this reduction in weight being attributable to the aluminium crankcase with its thermally inserted grey-cast-iron cylinder liners.
This optimisation of the engine ensured from the start in the construction process not only enhances the car’s economy, but also, through the reduction in engine weight, benefits the front-to-rear balance of weight.
The result, clearly, is even greater agility on the road.

Both turbodiesels featuring a particulates filter as standard.
Representing a new generation of diesel engines, the power units in the BMW 123d Coupé and the BMW 120d Coupé come as standard with a diesel particulates filter close to the engine. This ensures highly effective optimisation of the engine’s emission behaviour also in this segment of the market.


Brake Energy Regeneration reducing fuel consumption and enhancing driving pleasure.
All variants of the BMW 1 Series Coupé available in the European market come with Brake Energy Regeneration incorporating intelligent alternator control. Applying this principle in the new BMW 1 Series Coupé, the battery is charged only after reaching its minimum charge level during application of the brakes or in overrun, and is disconnected electrically when accelerating.
On the road this means more power for sheer driving pleasure typical of BMW and, at the same time, a reduction of both fuel consumption and CO2 emissions.
This concept of intelligent energy management may be compared with the operation of an energy-storage power station, where low-cost energy is stored at night in reservoirs at a higher altitude and retrieved again during the day to cope with peak loads. Now applying this principle to Brake Energy Regeneration in the new BMW 1 Series Coupé, the driver is able to store energy in the battery under driving conditions requiring only a low amount of energy, then feeding this energy into the car’s on-board network whenever required.
To maximise the service life of the battery and set off the higher flow of energy, BMW’s system of intelligent energy management operating in conjunction with new AGM battery technology introduces so-called regeneration cycles.
This means that higher voltage pulses are delivered to the battery after a certain charging and discharging phase in order to provide appropriate phases of regeneration.
Auto Start Stop function shortening idle speed running phases.
On manual gearbox models with the new four-cylinder power units BMW’s Auto Start Stop function provides greater efficiency above all in city traffic by automatically switching off the engine whenever it is not required. Fuel consumption when the car comes to a halt at the traffic lights, therefore, is reduced to zero.
As soon as the driver shifts to neutral and takes his foot off the clutch, the electronic engine “brain” will switch off the engine automatically and without a sound. Then, to re-start the engine, all the driver has to do is press down the clutch pedal. And by maintaining turbocharger pressure at the requisite level, the engine will start again instantaneously without requiring any further action on the part of the driver. New functions incorporated in the BMW 1 Series Coupé provide ideal conditions for the effective use of fuel also while driving.
For this purpose the new variants of the new BMW 1 Series come, for example, with a gearshift point indicator, the electronic engine control unit calculating the best point in time for shifting up as a function of driving conditions and in the interest of optimum fuel economy. An arrow symbol illuminated in the instrument cluster, together with a number presenting the best gear, then shows the driver the ideal point for shifting gears.

Last Updated on Monday, 12 April 2010 14:43  

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