Press Kit: The new smart fortwo
Madrid
Jan 31, 2007
Agility: more power and more driving fun
Powerful petrol engines
State-of-the-art compact three-cylinder engines are installed at the rear of the new smart fortwo. The all-aluminium engines were developed in cooperation with Mitsubishi, and are produced in Japan. They have been optimised for use in the new smart fortwo.
Naturally aspirated petrol engines rated at 45 kW (61 bhp) or 52 kW (71 bhp) are available, as is a turbo engine delivering 62 kW (84 bhp). They all have capacity of 1.0 litres. In addition to the increase in power, the maximum speed has also been increased – to 145 km/h (electronically limited).
The engine is mounted transversally in front of the rear axle, and is slanted at an angle of 45 degrees towards the rear. The cylinder barrels take the form of grey cast iron liners. Gas exchange is controlled by four valves per combustion chamber. The valves are controlled by separate intake and exhaust camshafts, via bucket tappets. The camshafts are driven via a maintenance-free timing chain.
The engine reacts spontaneously to accelerator pedal movement even at low revs and demonstrates how effectively the three-cylinder engine's variable valve control works. The intake camshafts are twisted electrohydraulically against the exhaust camshafts, providing for better filling of the combustion chambers at low revs. This gives the smart noticeably greater agility, especially in city traffic.
The 52 kW (71 bhp) version accelerates from 0 to 100 km/h in 13.3 seconds, giving it a head start against some other cars at the traffic lights. And that's no surprise – after all, a smart fortwo weighs in at just 750 kilograms. The 62 kW (84 bhp) turbo version is even more dynamic sprinting from 0 to 100 km/h in 10.9 seconds.
The three-cylinder engine develops its typical beefy sound without being rough or loud. Because the masses being moved are low, there is no need for a balancer shaft – which would reduce the output of the engine. The turbo version has a torsional vibration damper on the crankshaft.
To ensure a long service life, the turbocharger is fitted with a water cooling system, while the charge air cooler is based on air/air technology and is located behind the transmission. The maximum charge pressure is 0.5 bar, with control taking place via a wastegate valve in the turbocharger. The naturally aspirated engine's compression ratio is 11.5:1, while in the turbo engine it is 10:1.
smart fortwo cdi: there's no more economical way of running a car
The modifications to the diesel engine have led to a ten percent power increase, which means that the engine now delivers 33 kW (45 bhp), but also consumes less than before. The new smart fortwo cdi achieves the coveted "three-litre car" status.
The smart fortwo cdi emits just 90 grams of CO2 per kilometre, corresponding to standard consumption of just 3.4 litres. At present there is no more economical car than the smart fortwo cdi.
New transmission improves shifting comfort, consumption and agility
In future, smart fortwo drivers will benefit from a newly-developed transmission that will take no time to get used to. Instead of the previous six gears, the transmission produced by the specialist Getrag now has five gears, and offers considerable advantages in terms of comfort, fuel consumption and agility.
In the new smart fortwo there is once again no clutch pedal, as this task is performed by an electric motor. If the shift lever on the centre console is briefly tapped forwards, the transmission will shift up a gear, and if it is drawn back, down a gear. Alternatively, the gears can be changed by means of paddles on the steering wheel (standard for pulse).
To the right of the manual level, marked with a plus and minus sign, is the neutral position, N. Reverse gear is engaged by pulling the shift lever backwards from this position.
The smart fortwo passion comes with the automatic gear programme (softouch) as standard (optional for pure and pulse). It can be recognised by a small button on the shift lever.
When this is pressed down, the transmission switches over from manual gear shifting (softip) to the automatic gear programme. It’s the ideal solution for use in stop-and-go traffic. As soon as the driver moves the shift lever manually, the system returns to manual gear-changing mode.
The developers have also greatly improved the shift delays. Shift delays have been reduced by more than half compared to the previous model. This is particularly beneficial when the driver wants to shift down two gears at once. This, coupled with the considerably increased torque, makes for even greater ride comfort. To improve ride comfort even more, the transmission has a kickdown function.
This allows the driver to use the accelerator pedal to shift down two gears at once, in both manual and automatic mode. Incorrect gear changing and overrevving are impossible, because the electronics will only accept logical gear changes.
Driving dynamics
Thanks to extensive changes to its suspension, and its new geometry, the smart’s handling has been significantly improved. It is now considerably more agile and responsive than its predecessor. However, despite the car’s more sporty design, no compromises are made on comfort, and longer journeys present no problem at all for the new smart fortwo.
The wheelbase has increased by 55, the front track widths by seven, and the rear track widths by 31 millimetres. This reduces pitching and rolling movements. The anti-roll bar at the front is now directly hinged to the McPherson strut instead of the wishbone for better responsiveness.
The diameter of the anti-roll bar is 18.5 millimetres, and it very effectively prevents the vehicle body from rolling in bends. Tyres measuring 155/60 R 15 at the front are fitted at the factory on 4.5 inch steel rims. The passion boasts alloy wheels in the same size. The pulse equipment line comes with alloy wheels measuring 175/55 R 15.
The tried-and-tested DeDion construction has been kept at the rear. The position of the central mount has been changed (moved higher), which has had a positive effect on the manoeuvrability of the fortwo. The springs are now further out than in the previous model, thereby supporting the vehicle body even more effectively against rolling. The size of the tyres on the rear axle in the basic version is 175/55 R 15 on 5.5-inch rims. For the pulse the dimensions are 195/50 R 15.
The steering greatly influences the agile driving feel: the transmission ratio is 22:1. This means that the steering is transmitted almost ten percent more directly than that of the predecessor. The turning circle is just 8.75 metres – a figure unmatched by any other small car. This makes manoeuvring extremely easy.
It allows turning in places where any other car would have to shunt to and fro. And it’s just 3.5 turns of the wheel from stop to stop. Electric power steering is available for the smart fortwo at an extra charge.
The transmission ratio is just 21:1. It operates on a linear basis and gives the fortwo astonishingly agile handling. The electric boost power varies according to vehicle speed, steering angle and the amount of force applied to the steering wheel.
All these measures mean that the smart is now even sprightlier than before. It is noticeably agiler, sportier – and at the same time more comfortable.
esp is a standard feature
The electronic stability programme esp with integrated abs and electronic brake-force distribution are included in the standard spec, as is a hydraulic brake booster. Whereas other manufacturers in the micro car segment only offer esp subject to an additional charge – if at all – esp is a standard feature in the smart fortwo.
The fortwo is the only car in its class to come with brake assist. When it detects abrupt emergency braking, brake assist automatically provides full brake pressure in order to ensure optimum deceleration. It offers a helping hand in those situations where the driver has pressed the brake pedal quickly, but not firmly enough.
Because the electronically limited maximum speed of the petrol engines has been increased, the smart fortwo’s brakes have grown as well. Disc brakes are fitted at the front, while drum brakes are fitted at the rear.
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