BMW showcases its new energy-efficient modelsMay 8, 2007
BMW has launched the revised 1 Series and the revised 5 Series, both of which have energy efficiency innovations in both the petrol and diesel models. Also on show at BMW’s Multi-Model launch event was the Hydrogen 7 – but it wasn’t quite available to drive – yet.
The 1 Series
Both the 1 Series and the 5 Series have had a mid-life ‘refresh’ rather than being completely new models. However one change is that the 1 Series is now available in a 3 door bodyshell, which helps to make the car look slightly more sporty. Very minor styling revisions have also been carried out to the front and rear. However the big news is the introduction of new technology to improve fuel consumption and lower emissions.
You can get a 1 Series in 1.6, 2.0 and 3.0 litre petrol options (but note that the 1.6 is less economical than the 2 litre!) or just one (2 litre) size in diesel – but with two power options.
The headline news is that the new 118d (the lower powered 2 litre diesel engine) manages over 60mpg, and emits just 123g/km CO2. Even the petrol 118i can return 47.9mpg, with just 140g/km CO2. However perhaps the most interesting figures are these: the 118d can manage 68.9mpg on the extra urban cycle, whereas the Toyota Prius only returns 67.3mpg on this cycle; perhaps this makes the 1 Series one of the most economical cars above supermini size for everyday driving, ie. on motorways and A roads.
Of course the other thing to be aware of is that there are no other rear wheel drive cars of this size that are this economical. So if you want a car that’s powered by the rear wheels, which lets the front wheels get on with the business of steering, and you want great economy, especially during everyday motoring, then you need to give serious consideration to the 1 Series.
So the 1 Series range is now powered by engines offering increases in output by up to 20hp, but at the same time emissions have been cut by up to 21 per cent and fuel consumption by up to 24 per cent. For business users this means a reduction in company car tax of more than £500, courtesy of lower CO2 emissions. And all 1 Series diesels have particulate filters which prevent the emissions of the vast majority of the particulates that are so harmful to local air quality – although BMW doesn’t seem to make a big deal of advertising this (along with many of their other environmental benefits).
BMW uses the term ‘EfficientDynamics’ to describe their rear-wheel drive ‘driver’s car’ approach, combined with improved energy efficiency measures such as lightweight materials, in order to improve power and performance, and also economy and emissions.
Innovations such as Brake Energy Regeneration, Auto Start-Stop and Electric Power Steering are combined with lower rolling resistant tyres and an optimum gear shift indicator to deliver more economical motoring.
These innovations are in addition to the use of variable valve technologies and, for the first time on the 1 Series, high-precision direct injection engines on most petrol models that boost power output but, at the same time, cut fuel consumption and emissions.
The 118i and the 120i (both of which have the same 1,995cc four-cylinder petrol engine) show significant improvements in performance compared to the powerplants they replace. The 143hp 118i has a 14hp improvement while, at the same time, offering a 24 per cent drop in fuel consumption and a 21 per cent reduction in emissions. Similar gains have been made with the 120i.
Brake Energy Regeneration (iGR) makes its debut on the 1 Series (and the revised 5 Series). The system uses an Intelligent Alternator Control (IAC) and an Absorbent Glass Mat battery to recycle previously lost energy to save fuel. This is achieved by the alternator reducing drag on the engine by only engaging when required to charge the battery. A traditional alternator is always drawing power from the engine. Additionally, the energy generated by the engine on over-run (under braking or descending a hill) was previously wasted. Now this lost energy is utilised by the IAC to charge the battery. iGR alone is responsible for a three per cent improvement in fuel economy and may be seen as a (very) mild hybrid system.
The new 1 Series comes with Auto Start-Stop to further enhance economy. Standard on all manual transmission models (except the 116i and the 130i), the system automatically switches the engine off when the vehicle is stationary and the driver puts the car into neutral and releases the clutch pedal. To restart, the driver just needs to engage the clutch again before selecting a gear and pulling away in the normal manner.
The automatic Start-Stop function only works under certain conditions. It won’t work if the battery is almost flat, in very high (more than 30 degrees C) or very low (below 3 degrees C) outside temperatures, if the interior temperature within the passenger compartment hasn’t reached the level chosen on the air-conditioning, or if heating power is required to de-ice or de-mist the windscreen. And the Auto Start-Stop can be switched off using a button on the dashboard.
Another part of EfficientDynamics is the use of Electric Power Steering that results in a 90 per cent energy saving compared to a conventional mechanical hydraulic steering system, and this is now fitted to all BMW 1 Series. Power assistance is now provided by an electric motor that works only when required, such as turning a corner. Because the system doesn’t constantly drain power from the engine it leads to an approximate three per cent performance improvement. An Electrical Power Steering system also weighs less than a conventional hydraulic arrangement so this also benefits performance. The steering system’s fluid is of a higher viscosity to reduce friction and improve efficiency. The air-conditioning power supply and various ancillary devices also disconnect from the drivetrain when not in use.
Aerodynamics also play a role in improving performance and economy; on SE versions of the new 1 Series, flaps behind the grille close for improved aerodynamic efficiency when the engine requires less airflow. The feature improves cold starting times by closing the vents on start-up to retain engine heat and improve operational efficiency at an early stage.
The revised 1 Series is equipped as standard with low rolling resistance run-flat tyres to enhance economy and an optimum gear shift indicator located on a central display ahead of the driver to highlight the best, and most fuel-efficient, time to change gear.
All petrol engines (except 130i) in the revised 1 Series now come with high-precision direct injection engines. These provide a very accurate volume of the fuel/air mixture to be injected into the combustion chamber. It allows the engine to run with a higher compression ratio – another way to improve the engine’s efficiency and help to reduce fuel consumption.
The performance gains from using high-precision direct injection are made possible by the use of piezo injectors between the valves and the spark plug. Each injector delivers up to four bursts of a consistent jet of fuel into the combustion chamber with a resulting clean and complete burn of fuel. The result is more power but less consumption because unspent fuel does not pass into the exhaust system.
So what’s the new 1 Series like to drive?
The economy winner – the 118d
The 1 Series, with the 118d, gives us a car that can manage more than 60mpg, and that is also a quality, rear-wheel drive experience. The refined nature of the car is evident from the moment you get in, and it feels far removed from the lightness of most of the front-wheel drive options you are faced with in the majority of cars of this size.
The experience of a different class of car is enhanced by the stop/start button. Then putting the car into gear, with its relatively heavy feel, gives you an indication that this is a more substantially-engineered car than the majority of rivals.
One of the next things that you’ll be aware of – in a positive way – is the turbodiesel engine; it’s very smooth and quiet, and you’re certainly not conscious that it’s an obtrusive diesel in terms of feel or performance. The 118d is the smallest diesel, and in normal driving you really can’t notice a great deal of difference between this and the 120d, even though the 120d has 177hp as opposed to the 118d’s 143hp (note that both the 118d and the 120d have the same size 1995cc engine). The petrol 118i (remember this is a 2 litre and more economical than the 1600cc petrol model) feels lighter and more responsive than the diesel, and this should be weighed up against its combined 47.9mpg, compared to the 60.1mpg of the 118d.
And of course BMW always strives to achieve a near 50:50 front:rear weight distribution to aid with optimal handling. This gives BMWs their trademark looks with minimal front overhang due the engine slung rearwards of the front wheels. This contributes to the way car feels so well balanced through corners, and body control is excellent. Combined with sharp steering, few small family car rivals can match this driving experience.
The BMW 1 Series comes with Dynamic Stability Control (DSC) as standard. This system includes functions such as ABS and Automatic Stability Control to prevent the drive wheels from spinning while the car is accelerating and includes Cornering Brake Control that stabilises the car when applying the brakes in a bend. DSC prevents the car from oversteering or understeering, by reducing engine power or applying the brakes specifically on individual wheels as required.
If you don’t want the car to exert too much control on how you want to drive, the influence of the traction control can be reduced (without getting too technical, the 1 Series has a DSC button – push this and you get Dynamic Traction Control (DTC), a ‘sub-function’ of DSC. This is supposed to allow a 10 per cent greater degree of wheel slip than with DSC – it’s designed to allow more progress on slippery surfaces such as snow and ice when pulling away.) If in doubt as to whether this really makes much difference, without having to resort to high speed testing on wet hairpin bends, the effects of the disengagement can easily be demonstrated by the amount of wheelspin that can be generated at low speeds on loose surface car parks with the button de-activated.
Life inside the 1 Series is good; accommodation in the front is fine, however rear access is tight – especially in the new 3 door version. There are different levels of model which give you varying standards of equipment; whichever you go for, the accusation is always that BMWs are expensive to buy; however as compensation, they hold good residual values.
What could be improved? Well, the looks of the 1 Series are not to everyone’s tastes. The overall design doesn’t sit too happily, but it’s not helped in particular by those headlamps – they just look too bulging for the relatively small frontal area of the car.
Getting reverse gear on most BMWs always seems to be a bit of a fight, and you almost feel you’re doing damage to the gearbox by having to force it so heavily.
And try as we might, we just couldn’t get the Stop-Start feature to do much stopping. We can only assume that this was due to the air conditioning having to work too hard to fight off the global warming that was showing its presence outside the car.
So what’s the verdict? BMW aren’t going down the road of promoting the 1 Series as a green car. Instead they are using their strapline ‘EfficientDynamics’. You can take this to mean that their cars are efficient yet also rewarding to drive from a dynamics point of view. And that really sums up what this car is all about. Here is an energy-efficient car that is also a driver’s car. And for that BMW must be applauded.
The 118d 3 door costs £18,225.
The 5 Series
The 5 Series is held up as the benchmark Executive driver’s car. Many of the overall comments above about the technical innovations on the new 1 Series are also applicable to the 5 Series. Again, it is a mid-life refresh rather than a new car, with minimal, subtle styling revisions to front and rear. And again, the energy efficiency improvements are the main news.
With the 5 Series, improvements of up to 25 per cent in economy and emissions have been achieved throughout the range. In this sector, this translates into considerable savings in company car tax.
Let’s look at some figures. The 520d manages a combined fuel economy of 47.9mpg, and emissions of 158g/km. Compare this to the hybrid Lexus GS450h – 35.8mpg and 186g/km. However, with its instant torque from the electric motor, the Lexus has excellent acceleration, and is more of a hybrid performance statement than an out-and-out eco car.
The best performing petrol model is the 523i which manages 38.7mpg and 174g/km CO2. And the Touring (ie. the estate) version of the 520d is very close to its saloon counterpart in terms of economy – 46.3mpg and 162g/km CO2.
So if you want maximum economy, lowest emissions, and a considerable saving on company car tax – the 520d is the one to go for. But hang on a minute. Isn’t the engine in the 5 Series the same 4 cylinder 1995cc diesel as the one in the 1 Series? The 5 Series is a much larger car, and must weigh much more. Surely the 520d (163hp) must be extremely sluggish with the same engine as such a smaller car (177hp in the 120d). Actually, the 520d actually moves itself along very respectively. Take a look at the weights of the two cars and start to see why: the 520d weighs 1585Kg, compared to the 120d’s 1450Kg. Here lies an insight into what BMW has done to the 5 Series; in addition to similar energy efficiency engine technology measures described above for the 1 Series, the 5 Series has been on a diet – one of the secrets to improved energy efficiency that few mainstream manufacturers are making the most of.
When originally launched in 2003, the 5 Series featured BMW’s first foray into an aluminium and steel composite chassis. The entire car in front of the A-pillar was made from aluminium and the rear constructed from high-strength steel. Since then, other weight-saving technologies have been introduced that help to reduce fuel consumption.
One interesting development is that BMW has managed to develop a new 6 speed automatic gearbox that makes the 530i (37.7mpg) more economical than the manual version (36.7mpg). Compared to the previous automatic version of this model, the CO2 emissions are reduced from 224 to 178g/km, and the mpg is improved from 30.4 to 36.7 (66 percent of owners chose an automatic in the outgoing model).
The improvements are mainly due to a new two-stage torque converter on petrol-engined cars and a twin-stage damper on diesel-engined cars. In simple terms, both of these devices help to smooth out engine vibrations and power pulses from the engine, allowing the torque converter to be locked up earlier in the rev range and reduce slip in the drivetrain. The result is a more direct drive from the engine to road wheels and therefore significantly improved economy. A more direct drive in an automatic from the engine to the wheels? Let’s hope we see this feature introduced on all automatics soon.
So what’s the new 5 Series like to drive?
The economy winner – the 520d
The 520d is the most economical 5 Series, returning 47.9mpg. As described above, this is effectively the same engine as in the much smaller 1 Series, and it manages to move the 5 Series in a surprisingly effective way.
As with all diesels, the 520d has good low down pulling power and the six-speed manual is smooth. Under most normal driving conditions, the engine is quiet and refined.
BMW has managed to ensure the handling is excellent, while the ride comfort is also extremely comfortable. As with the 1 Series, an element of the traction control can be disengaged.
You’re pretty much guaranteed the seating position you want thanks to a multi-adjustable seat and steering wheel. As you would expect in a car of this size, there is plenty of space and the interior is a relaxing and quality place to be. Even the iDrive, controlling features such as navigation, audio and communication, has been improved and made more user-friendly. Wheel-mounted buttons provide controls for the stereo and climate control. You can even have an optional display that projects information onto the windscreen in the driver’s line of sight.
So what’s the verdict?
If you want an accomplished Executive car that is an enjoyable driver’s car and that also achieves class-leading economy and emissions, go for the 5 Series. Much business mileage is likely to be up and down the motorway, and the excellent 60.1mpg extra urban figure of the 520d will reduce your fuel bills, your tax bills, and possibly most importantly, your company’s carbon footprint.
If you want out-and-out power, then there are other engine options you can go for. However with the shift from power to responsibility that is taking place in corporate boardrooms around the world, the new 520d will be on more people’s radar, especially that of company accountants and CSR directors.
The 520d SE costs £26,980.
The Hydrogen 7
Hydrogen is seen in many people’s eyes as the dream fuel of the future. Emitting only water, it has great promise, but equally there are a number of technical hurdles to be overcome in areas such as production, storage and infrastructure.
BMW has been carrying our research and development on hydrogen cars for 25 years, and the Hydrogen 7 is the latest test-bed.
The car on the display at the launch event for the new 1 and 5 Series was the first one in the UK, although more Hydrogen 7s are arriving very soon. BMW say that certain high profile individuals will be using the cars.
The car is based on a normal 7 Series, from the same production line as the standard car, but it has been developed to run on liquid hydrogen. Hydrogen is in short supply, especially in the UK, where at the moment there is just one refuelling station in Wembley, so the 7 has a hydrogen tank and a petrol tank, and the engine can run on either fuel. The hydrogen, stored in liquid form at minus 253 degrees, is then converted into gas before being burnt in the combustion engine.
Hydrogen infrastructure is more developed in Germany and California, but two more hydrogen stations are planned in London for next year. BMW see a reasonably developed hydrogen infrastructure as being 10-15 years away. We just need to ensure we also develop a sustainable, efficient and cost-effective production process (hydrogen is being produced in the US today from solar and wind – ie. from renewable energy).
Watch this space for more future fuel developments…