Din nettleser støtter ikke lengre dette innholdet, vennligst oppgrader din nettleser.
MICRA CLEANS UP
With one of the lowest CO2 emissions of any petrol engine - just 95 g/km - the latest version of the new Nissan Micra is set to clean up in the city
"Low emissions with no compromise when it comes to drivability and cost, means the new 1.2 DIG-S Micra sets new standards for the current generation of city cars. No other petrol-powered compact hatchback can match its overall efficiency... and it is more than a match for an equivalent diesel." Pierre Loing, Vice President Product Strategy and Planning, Nissan International SA
At a glance
Nissan's focus on reducing emissions has led to the creation of the Nissan LEAF, the world's first practical zero emission vehicle - the battery-powered electric car produces no tailpipe emissions at all.
But Nissan hasn't abandoned the internal combustion engine. Far from it. The challenge to make significant reductions in CO2 emissions from conventional engines has resulted in the development of one of the most technically advanced petrol engines yet seen.
The embodiment of Nissan's ‘Pure Drive' technology, the new 1.2-litre three-cylinder engine delivers sparkling performance, frugal economy and an exceptionally low emissions figure of just 95g/km, one of the lowest ever achieved by a petrol engine. It has been designed to meet and exceed the everyday driving demands of the modern world.
Technical innovation has been packed into the engine. It uses the Miller cycle and direct petrol injection with a compression ratio of 13 to 1 for greater efficiency and a supercharger for instant throttle response and added power.
This exceptional engine makes sub 100g/km emissions performance easily accessible while low cost of ownership make it a serious alternative to a comparable diesel... with the added bonus of greater refinement.
Its first appearance powering the new Micra makes for an irresistible combination. Micra's city car credentials have been honed over decades of class leading models. The newest Micra, launched late last year, is the perfect city car being compact on the outside but spacious inside.
City driving is eased by the class leading all-round visibility and Micra is packed with technology that is not only innovative but actually useful, too. Available either as standard or an option are features such as Nissan Connect, a fully integrated entertainment and information package incorporating touch screen satellite navigation.
But perhaps the most useful feature for a city car - and technology that's rarely found on much larger cars - is the Parking Slot Measurement (PSM) system. As its name implies, the system measures potential parking spaces and lets the driver know whether it is large enough for the car or not.
"When it comes to performance figures, the first one that city car buyers look at these days is emissions performance. The new Micra Direct injection Gasoline-Supercharger certainly tops the emissions tables, but the clever technology under the bonnet also means its ‘conventional' performance is equally impressive," said Pierre Loing, Vice President Product Strategy and Planning, Nissan International SA.
"With the instant responses and refinement only a petrol engine can provide, coupled to a taut yet comfortable new platform, and plenty of advance technology like PSM the new Micra is equally at home on the open road as it is in the city," he said.
The DIG-S engine
At the heart of the newest Micra lies a truly remarkable engine, specifically created to meet the low emission and everyday performance demands of the modern world. It gets its name from a combination of direct fuel injection and supercharging technology: Direct Injection Gasoline-Supercharger.
But as well as delivering ultra low CO2 emissions, the lightweight, low-friction 1,198cc DIG-S three-cylinder unit produces the power expected from a conventional 1.5-litre four-cylinder engine.
Further efficiency gains are made thanks to the adoption of advanced engine management systems with Start/Stop and energy regeneration.
The secret to its remarkable figures is the adoption of two technologies specifically designed to reduce losses and enhance combustion efficiency - the Miller combustion cycle and a supercharger. By minimising heat, friction and pumping losses as much a possible and combining it with an unusually high compression ratio of 13 to 1, Nissan's engineers have created an engine that sets the standard for the rest of the industry.
Enhancing technology already seen on many Nissan gasoline engines in the recent past, the new unit has mirror-finished components to reduce friction as far as possible.
The camshaft bearing is given a nano-level polish on its sliding surfaces, while Diamond Like Carbon (DLC) coatings are used on the valve lifters and - a world first - on the piston rings. The hydrogen-free DLC coating cuts friction by as much as 50 per cent on the valve lifters and 18 per cent on the piston rings, compared with no coating.
Its three-cylinder configuration gives many benefits including less weight and further reductions in friction loss, thanks to having fewer moving parts.
Miller Cycle, direct injection and supercharger
The Miller combustion cycle raises the compression ratio - in this case to 13 to 1- by modifying the conventional Otto four stroke cycle. It leaves the intake valve open longer effectively turning the compression stroke into two separate cycles: part one when the valve opens, part two when it closes. With this two-stage intake stroke, the Miller cycle is ideally suited to direct fuel injection technology.
When the piston moves upwards at the start of the compression stroke, because the intake valve is still open resistance is less resulting in lower pumping losses. At the same time the temperature of the mixture is lowered thanks to the delay in the start of the combustion process, which happens at a point about 25 per cent into the combustion stroke.
To overcome the potential loss in power caused by the expulsion of the charge in the initial stage of the stroke, Nissan engineers have adopted a supercharger to boost power. The intake air is compressed by the supercharger and then cooled with the result that the lower charge temperature permits the ignition timing to be advanced without fear of detonation or knock, thus improving overall efficiency still further.
Benefits include lower fuel consumption, lower CO2 emissions and, thanks to the supercharger, instant throttle response.
Careful design has ensured that inherent imbalances expected from a three-cylinder engine have been overcome: idle vibration, for example, has been eradicated by the inclusion of an offset counter weight on the crank pulley generating an oval motion which cancels out the vertical vibration caused by piston travel.
Other technologies designed to maximise fuel efficiency include exhaust gas recirculation (EGR) for improved combustion - approximately. 20 per cent EGR including internal EGR has been achieved - low friction water and oil pumps, high tumble pistons
Even the valve springs have come in for attention. Called ‘beehive springs' after their shape, they have a smaller diameter at the top which is fully integrated into its retainer to create a more compact unit. The benefits are reduced inertia and improved fuel-efficiency.
Completing the low emission package is Nissan's Start/Stop technology which cuts the engine at idle and can improve fuel economy. Coupled to a high performance battery and starter motor, the system takes just 0.4 secs to restart the engine once stopped (CVT).
Energy regeneration under deceleration via the alternator helps recharge the battery so it can be used for direct energy supply to ancillary electric items, thus reducing the load on the engine.
The results are spectacular. The Direct Injection Gasoline-Supercharger engine produces 72kW (98PS) and 142Nm, while CO2 emissions are 95 g/km for the manual version and 115 g/km for the CVT version. Maximum speed is 180km/h (manual) and the combined cycle fuel economy is 4.1 l/100km (manual, Visia grade).
In common with industry practice, these headline figures refer to the entry-level version - Visia - as higher levels of equipment found in plusher models invariably mean extra weight which affects emissions performance. But such is the efficiency of the unit that the most popular version, Acenta, also promises an exceptional CO2 figure: just 99 g/km in manual form.
Low running costs are guaranteed not just by the exceptional fuel economy but also thanks to tax concessions based on its emissions granted in many European countries and to lower servicing bills from the smaller engine.
The normally aspirated Micra has power and torque figures of 59kW (80PS) and 110Nm for a maximum speed of 170km/h with 0-100km/h taking 13.7 seconds. Combined consumption is 5.0 l/100km (CVT: 5.4 l/100km) while CO2 emissions are 115 g/km for the manual version and 125 g/km for the CVT model.
For comparison, the previous generation Micra diesel developed 63kW (86PS) and 200Nm of torque from its 1.5-litre four-cylinder turbocharged diesel engine. It produced 120 g/km of CO2. Maximum speed was 171km/h with 0-100km/h taking 11.9 secs. Combined cycle fuel economy was 4.6 l/100km.
"It is clear that our new Direct Injection Gasoline-Supercharger engine offers the best solution for small cars like Micra. With instant throttle response, its performance and strong economy are a more than a match for any diesel engine with similar power outputs, but its emissions performance is much better," Pierre Loing.
"We have been able to achieve this ultra low CO2 figure in a cost effective package and without the complication of particulate filters needed to clean up diesel engine emissions and which are not entirely compatible with a car that spends much of its life in the city."
In other respects the car is all but identical to the all-new normally aspirated Micra introduced at the end of 2010. Both cars wear Nissan's Pure Drive badges, signifying they produce CO2 emissions lower than 130g/km... but there are no others badges identifying the two versions.
Indeed, the only external difference is that the newer model has an extended rear roof spoiler which, in conjunction with a small lip spoiler at the front of the car, reduces the drag coefficient from 0.33 to 0.29.
Bristling with new technologies and based on a brand new platform, the fourth generation Micra for Europe is built at an entirely new facility in India. It is also built in China, Mexico and Thailand and is sold in 160 countries around the world.
The model line-up is simple with just one five-door body style, two engine options and two transmission choices - either a five-speed manual or an advanced and compact Continuously Variable Transmission (CVT). This new generation XTronic CVT is 13 per cent lighter than previous versions, has a 30 per cent improvement in friction losses and has a higher final drive ratio for improved economy.
Grades follow traditional Nissan practice with Visia followed by Acenta and then Tekna. All models have power steering, electric front windows, six airbags (driver, front passenger, side airbags and curtain airbags) and the Electronic Stability Programme (ESP) as standard. Manual or automatic air conditioning is standard on all models except the entry level non-supercharged Visia model.
Acenta adds an enhanced sound system, automatic air conditioning and a cruise control among other features, while the range-topping Tekna introduces technology seldom seen in bigger cars let alone a compact city car. As well as Nissan Connect, a combined satellite navigation and entertainment system, Tekna versions offer Parking Slot Measurement as standard.
PSM automatically measures potential parking spaces advising drivers whether the Micra will fit or not. It's a perfect feature for a city car.
Avoiding the temptation to ‘super-size' the new car, Micra has stayed true to its city car heritage and is virtually the same size as its popular predecessor. Overall, new Micra is longer by just 61mm, marginally wider by 15mm and 20mm lower than before..
Although borrowing some design elements from the third generation Micra, the new profile is bolder with a strong rounded waistline and distinctive crease above the sills.
Front and rear treatments, though, are totally different with a dominant grille that defines the car's on road presence. The two-part grille is divided by the front bumper. Above the line sits a slim opening split by a chrome bar on Acenta and Tekna models and topped by an indentation housing the Nissan badge.
Below the bumper, a deeper opening extends to virtually the full width of the car and houses the front number plate. On Tekna models, the grille has a distinctive chrome surround. The look is complemented by softly rounded one-piece headlamps.
As on its predecessor, raised front wings help the driver to ‘place' the car on the road more accurately, while the low waistline also provides excellent visibility to either side.
At the rear, the deep tailgate is flanked by one-piece tail light assemblies while the bumper features a neat cutaway for the number plate. A central high mounted stop lamp is integrated into the roof spoiler.
Aerodynamics played an important role in defining the overall shape of new Micra. The sleek roof design, complete with the pronounced rear spoiler, combine to minimise drag to help economy and reduce emissions. The roof itself, has been embedded with boomerang-shaped grooves which help reduce resonance in the cabin, especially at higher speeds at the same time as reducing overall weight by up to 2kgs.
Aiming to create the same sense of style inside the Micra as can be found outside, the design team adopted a ‘connected cocoon' approach. One example is the dashboard design - a twin bubble theme - which matches the circular instrument binnacle with a similarly shaped glovebox ahead of the passenger. This double-layered glovebox is complemented by a large upper storage area while other small storage pockets are located throughout the car, including the centre console and doors.
Easy to read instruments are housed in three circular dials while the heating and ventilation, audio and other controls are logically placed and easy to operate.
A proportion of European customers may be downsizing into a city car if their kids have left home, for example, but they don't want to feel that they must accept a compromise on interior space.
The clever engineering solutions provided by the V-platform means that the slightly longer wheelbase has increased interior space compared with the previous generation Micra, improving ingress and egress for all occupants. The long roof line, meanwhile, ensures that Micra offers ample rear headroom, so that new Micra's overall interior roominess is hard to reconcile with its compact exterior dimensions.
Throughout the design process, weight saving was a key consideration and was met by reducing the number of parts at the same time as improving quality. New Micra has, on average, 18 per cent fewer components than similarly sized cars: its dashboard alone comprises 27 parts instead of more than 50.
Underpinning the new Micra is a new platform - V for Versatile - which, in time, will feature widely across the Renault-Nissan Alliance global range.
Even though it is slightly larger than the outgoing Micra - the wheelbase has grown by 20mm to 2450mm for example - the platform has been engineered to deliver optimum rigidity for excellent handling characteristics coupled with a refined ride, but at the lowest possible weight for enhanced performance, strong fuel efficiency and low emissions.
These seemingly contradictory requirements had to be reconciled to achieve new Micra's stated aim of meeting the expectations of customers who drive - and park - everyday in European cities, famed for their heavy traffic, limited parking opportunities, poor road surfaces and increased fiscal pressure on emissions.
Weight savings on the platform have been mirrored by judicious weight cuts elsewhere: the 41 litre fuel tank, for example, is 2.1kgs lighter than that in the outgoing Micra; the exhaust system no longer has a central silencer, reducing weight by 3.2kgs and the front suspension system is lighter by 9.6kgs.
As well as the lighter roof panel, more weight has been saved in the seats and the dashboard, which uses fewer parts. Overall new Micra boasts a kerb weight starting at just 915 kgs, 31 kgs less than its predecessor.
Building on the highly praised ride and handling capabilities of the previous Micra, the new model features a similar suspension layout with an independent front end by MacPherson struts with coil springs and a compact torsion beam rear axle designed to minimise intrusion into the luggage area. Both suspension systems are mounted on sub frames to help isolate road noise, vibration and harshness and there's an anti-roll bar at either end.
Thanks to the new, more rigid platform, the suspension can work more efficiently to provide more accurate steering with greater feel and precision while there's less dive under braking and pitch under acceleration. Particular attention has been paid to bump absorption - thanks to the adoption of long stroke suspension travel - Micra rides exceptionally well over even the most challenging of road surfaces.
Best of all, Micra's characteristic agility and responsiveness have all been preserved, indeed enhanced by the chassis' light weight, to provide a genuine dynamic driving experience.
Electric power steering is standard on all models, and helps provide Micra with a class-leading turning radius of just 4.65m for the ultimate manoeuvrability in tight city streets.
The car is designed to absorb the forces of a frontal impact, thanks to the sophisticated crumple zone at the front of the car, while maintaining the integrity of the cabin thanks to a highly reinforced body shell.
Standard safety equipment includes the braking system which features discs at the front and drums behind, with ABS, EBD and Brake Assist. Micra also has dual front airbags, curtain and side airbags, as well as pretensioner seatbelts. Active safety is reinforced with the fitment of Electronic Stability Programme (ESP) across all grades, which intervenes to cut power and even brakes individual wheels when sensors detect that stability or grip is critical. It has achieved a four star Euro NCAP rating.
Nissan's commitment to reducing the environmental impact of its products and activities can be clearly seen in the fact that more than 95 per cent of the materials used in Micra's construction are recoverable - a factor which is likely to be increasingly important as legislators throughout the world consider steps to protect the environment.
The standard transmission in both versions is a precise five-speed manual gearbox driving the front wheels but new Micra will also be available with a highly sophisticated CVT. This brand new transmission adopts a number of advanced technologies - it's the world's first CVT with a sub-planetary gear system for example - for the ultimate in smooth efficiency.
It also boasts the world's highest transmission ratio - 7.3:1 - allowing the transmission to deliver an enviable combination of good low speed response with strong high speed economy.
The adoption of a sub-planetary gear allows the use of smaller pulleys which means there's a greater distance between the pulleys and the oil surface in the transmission. This results in a reduction in the amount of oil ‘stirred' by moving parts which, in turn, means less friction.
Smaller components including an ultra flat torque convertor results in a unit that's 10 per cent more compact and some 13 per cent lighter than previous systems.
Equipment and model lines
Just like its predecessors new Micra is generously equipped as standard as well as introducing a number of innovative items of equipment which are designed to make city driving less demanding - and none more so than an advanced parking aid.
While such items have undoubted showroom appeal, they have only found their way onto Micra's specification lists because they will all make the typical European Micra owner's day-to-day life in the city simpler and easier.
Externally the versions differ in subtle ways: Visia has 14 inch steel wheels, and black doors handles and mirrors while Acenta has 15 inch steel wheels, a black B-pillar between front end rear doors, body coloured handles and mirrors and a chrome flash on the grille. Tekna variants can be identified by the chrome surround on the lower air intakes, front fog lamps and 15-inch alloy wheels.
All Micra models have a full complement of active and passive safety equipment with ESP standard across the entire range. Every Micra has front, side and curtain airbags, head restraints in the rear and anti-lock brakes. Automatic speed sensitive door locking is also standard.
Also standard are power steering with a tilt adjustable column, remote central locking, a trip computer and electric front windows.
The seat squab is hinged in the middle allowing the rearmost section to be folded over onto the front leaving a well into which handbags or shopping bags can be lowered.
Acenta, likely to be the biggest seller, adds automatic air conditioning, cruise control with speed limiter, electric door mirrors, a front armrest and height adjustable driver's seat. The steering wheel and gearshift knob are leather covered while the in-car entertainment system is upgraded to include a CD player with Aux-in facility and four loudspeakers. It also includes Bluetooth connectivity for mobile phone use. Practical features include a neat bag holder incorporated into the front passenger seat to prevent luggage rolling around the cabin when the car is on the move.
Tekna models introduce Nissan Connect to the Micra, a fully integrated entertainment and information package incorporating touch screen satellite navigation via a five inch colour screen, Bluetooth for mobile phone connectivity and audio streaming from a suitable device, Aux-in and USB slots, plus a six loudspeaker system.
The navigation system uses clear street mapping rather than the more basic turn-by-turn guides of cheaper systems and can be programmed in any of nine languages including Russian. The maps, which can easily be updated via an SD card, cover Western Europe, Eastern Europe and Russia.
By integrating information from positioning sensors and vehicle speed, the system does not suffer from loss of signal when driven through a tunnel or when ‘hidden' by high rise city buildings.
The system also incorporates TMC (Traffic Message Channel) which uses a second radio tuner to receive traffic flow information and news of incidents on major routes. By processing this real time traffic data, the system can suggest alternative quicker routes as appropriate, thus saving time and cutting emissions.
Standard on Tekna, Nissan Connect is available as an option on Acenta versions.
Also standard are automatic headlights and wipers, electrically folding mirrors linked to the optional Intelligent Key system - still a rare feature in the city car segment - with a smart push button engine start and stop function, and a comprehensive matrix information dashboard display. As well as providing information on fuel consumption, driving range, outside temperature and so on, it can also be programmed so that the Micra wishes its owner a happy birthday on the appropriate date.
Another example of how Nissan has pioneered the fitment of relevant technology on new Micra is the innovative and easy to use Parking Slot Measurement (PSM) system. It is standard on Tekna and optional on Acenta grades.
Reflecting Micra's likely role as a city car, PSM helps a driver establish whether a parking space is big enough for the car. As the driver eases alongside a space he or she activates PSM via a push button on the dash and then selects the appropriate turn signal to tell the system which side of the car it should be checking.
Assuming the car's speed is below 25 km/h, sensors then scan the space telling the driver whether it's suitable or not via a dashboard display. The display will suggest it's ‘OK' if the space is more than 100cms longer than the car, ‘DIFFICULT' if it's between 60 to 99cms longer than the car, and ‘NOT ADVISED' if it's less than 60cms. It's then up to the driver to decide whether to park or not...
Those tolerance levels can be adjusted to reflect the driver confidence and skill - Amateur, Normal and Expert - while the sensors are accurate enough to spot small obstacles such as bollards, traffic cones and so forth. When PSM is specified it comes complete with traditional reversing sensors which operate whenever reverse is selected and give both audible and visual warnings. Micra is the only car in its class to offer PSM.
Among the options, one of the most popular will undoubtedly be a glass roof covering the entire front half of the car virtually from the leading edge of the windscreen back to the B-pillars and extending virtually the entire width of the car. Transforming the interior of Micra by bathing it in natural light, the roof also features an integrated inner curtain for when the sun gets too hot for comfort.
"Regardless of which engine is chosen, new Micra is a car perfectly in tune with the times. The exceptionally low emissions, especially from the new supercharged version, mean it is the perfect city car: easy to drive, easy to park and among the cleanest petrol-powered cars on the planet.
"Yet despite its compact overall dimensions there is ample room inside the cabin and new Micra also benefits from technology and features usually found in much larger cars," said Pierre Loing.
"Micra is, without doubt, the right car for the times."