05.07.2007

Green engines


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The car comes with a choice of superb modern engines that guarantee sparkling performance. There are two petrol units (the 69 bhp 1.2 8v and 100 bhp 1.4 16v) and one Multijet turbodiesel, the 75 bhp 1.3 16v with DPF. Each offers different features, all of which are exploited fully by combining them with mechanical 5 or 6 speed gearboxes (a Dualogic sequential robotised 5-speed gearbox will also be available at a later date for the petrol engines), and they stand out for their generosity, brilliant temperament, top performance and advanced technology. However they all also share top reliability and respect for the environment. This has been demonstrated in over 1,600,000 km that the test cars have already travelled, which will become 2,350,000 km with the last tests. We should underline that all the engines are Euro 4-compliant and are designed to meet the even stricter limitations of future European standards (Euro 5), already meeting the emissions limits that will presumably be enforced in 2009. The 1.3 Multijet is also equipped with a particulate trap (PDF) as standard equipment.
All the engines mounted on the Fiat 500 are manufactured by Fiat Powertrain Technologies, the Group’s new sector. FPT draws together all the activities in the fields of innovation, research, design and manufacture related to engines and gearboxes for all types of applications: from cars to commercial vehicles, boats and agricultural machinery. With approximately 19,000 employees, 17 plants and 10 research centres in eight different countries, the Sector is one of the world’s most important organisations in its field. At FPT, approximately 3000 highly specialised technicians focus on the development and engineering of innovative technologies. More than 40 patents are filed each year, confirming the quality and seriousness of this commitment, and making FPT a huge centre of technological excellence and ongoing innovation.


The 69 bhp Fire 1.2 8v

The tried and tested Fire engine that will power the Fiat 500 has a capacity of 1242 cc, and has undergone a series of refinements designed to make it a champion of fuel economy, but without detracting from performance. The engine delivers 51 kW (69 bhp) at 5500 rpm, and peak torque of 102 Nm (10.4 kgm) at 3000 rpm, with a top speed of 160 km/h. That is not all. With the 1.2 8v engine, the Fiat 500 leads its class for consumption, delivering 5.1 l/100 km in the combined cycle, with CO2 emissions of 119 g/km. Acceleration over 100 metres is also excellent at 12.9 seconds. This figure is even more significant in view of the car’s low consumption. The credit goes to the structure of the engine, which achieves a generous torque at low revs (this makes for more enjoyable driving and outstanding flexibility) and ratios chosen to highlight fuel economy.
A sparkling engine that is sparing on fuel. This has been achieved thanks essentially to:
1)The adoption of an electronic throttle valve control system known as ‘drive by wire’ (with no mechanical connection between the accelerator and the throttle), while it is the electronic control unit that delivers the torque on the basis of the driver’s demands (torque-based system).
2)Fluid dynamic optimisation achieved by a new high turbulence combustion chamber combined with a continuous variable cam phaser. This innovative system allows a substantial part of the exhaust gases (about 25%) to be recirculated in the combustion chamber, significantly reducing fuel consumption and exhaust emissions when driving with a partial load.
3)The timing components have been made lighter and the valve springs are of the low load type, to reduce friction.
Another interesting feature of this engine where fuel consumption is concerned, is the use of an active knock sensor capable of managing the advance in the best possible way in all conditions and, above all, the multipoint sequential phased injection system by Magneti Marelli.
The quality of life on board has also been improved by optimising the performance of the intake and exhaust systems, optimising the coupling play between the crankshaft and crankcase, through the computerised selection of the main bearings, and the development of a specific installation of the engine in the engine bay. This keeps the transmission of vibration from the engine to the bodyshell to a minimum. A special engine support system has been adopted, that comprises two blocks and a reaction link, which acts as a tie rod, in which the new bearings are aligned on an axis that goes through the engine’s centre of gravity in order to obtain reaction forces with a neutral arm.
On the environmental front, the 1.2 8v fits a catalytic converter in the engine bay, welded to the exhaust manifold flange. In this position the device is extremely efficient because it reaches high temperatures very rapidly thus abating emissions even while the engine is warming up.
The engine has been made even more reliable. The coils have been mounted closer together in a single block. This new type of coil means less spark plug wear, more energy available to ignite each plug thanks to the elimination of the lost spark, better cold starting due to the additional energy available for the spark plug (more energy supplied by the coil and no losses caused by the transfer of high voltage due to the adoption of very short cables), and finally, a significant reduction in the risk of disturbance to the onboard instruments due to high voltage cables.


The 75 bhp 1.3 Multijet 16v

The Fiat 500 would not be complete without the 1.3 16v Multijet engine, the smallest and most advanced second generation direct injection Common rail diesel unit, of which more than two million have been built to date.
Fitted with a Borg-Warner fixed geometry turbo (of the waste-gate type) with an intercooler, the engine delivers a maximum of 75 bhp (55 kW at 4000 rpm) and torque of 14.8 kgm (145 Nm) at 1500 rpm. With this engine, the Fiat 500 guarantees excellent performance: it has a top speed of 165 km/h and accelerates from 0 to 100 km/h in 12.5 seconds. Fuel consumption is also among the best for this segment: 5.3 l/100 km in the urban cycle, 3.6 l/100 km out of town and 4.2 l/100 km in the combined cycle, and CO2 emissions are among the lowest on the market at just 111 g/km.
The engine is a straight-4 with a capacity of 1248 cc, a bore of 69.6 mm and a ‘long’ stroke of 82 mm. There are four valves per cylinder, governed directly by a twin overhead camshaft with maintenance-free hydraulic tappets and automatic play take-up. That is not all. The 1.3 Multijet 16v is a miniature masterpiece: ‘dressed’ with all its accessories, it weighs just 130 kg, it is small, just 50 cm long and 65 cm tall, and the component layout was designed to take up as little space as possible. Designed by criteria of maximum rationality, efficiency and reliability, the engine guarantees excellent efficiency and is practically ‘for life’: it was designed to travel 250,000 km without needing any maintenance to the mechanical components.
The compact, sophisticated engine is also extremely eco-friendly, thanks to an emissions control system that envisages an EGR valve triggered electronically and managed directly by the engine control system, a heat exchanger to cool recirculating exhaust gas (EGR) and a ‘close coupled’ catalytic converter. A particulate trap (DPF), the ‘for life’ system that abates fine dust and does not need additives to be regenerated, is standard equipment.
The 75 bhp 1.3 Multijet 16v therefore represents a technological leap forward which, for the customer, translates into lower consumption and emissions, without even taking into consideration the reduction in noise (due to the multiple injections), the increase in comfort (fewer alternating masses means less vibration), the smooth, responsive steering (due to the really smooth torque delivery, which is guaranteed by the improved combustion control), the elasticity and prompt response of a diesel that resembles a petrol engine for the vast excursion in the number of revs (for example, you are no longer aware of the fuel ‘cut-out’ just above 4000 rpm), and the ecological elements that enhance the diesel’s main environmental credentials (consumption) while minimising its main defect (particulate emissions).


The 100 bhp 1.4 16v Fire engine

One hundred horsepower on hand on such a compact car points up a brilliant, agile character, which allows it to slip easily and cheerfully through congested town traffic. The engine has a capacity of 1368 cc and four cylinders in line, with a bore of 72 mm and stroke of 84 mm. There are four valves per cylinder, driven directly by the overhead camshaft. The engine was developed focusing particular attention on performance and consumption, fields in which the Fiat 500 leads its class. All credit to the volumetric efficiency which has been optimised throughout the operating range, thanks to careful fluid dynamic development of the entire intake system and timing phasing.
The 1.4 16v delivers a maximum of 73.5 kW (100 bhp) at 6000 rpm and peak torque of 131 Nm (13.4 kgm) at 4250 rpm. Performance is excellent: the new car has a top speed of 182 km/h, and accelerates from 0 to 100 km/h in 10.5 seconds. It is a sparkling engine with excellent performance enhanced by an electronic throttle valve control system known as ‘drive by wire’. This engine also proposes a number of changes that help to keep consumption down. For example, the timing components have been made lighter and the valve springs are of the low load type, to reduce friction.
Other features of the new 1.4 16v Fire are the increased compression ratio and the generous torque at low engine speeds, characteristics that have made it possible to limit consumption: for example, in the combined cycle it returns 6.3 l/100 km. This target was achieved by the calibration of the latest generation engine control system, which succeeded in reducing consumption as much as possible, compatible with the requirements of driveability, performance and emissions.
In order to guarantee low emissions, special injectors have been adopted that optimise the spray phase, thus reducing the quantity of petrol that adheres to the walls of the intake manifold during cold starting and in transients (when you depress the accelerator). This reduces the quantity of hydrocarbons in the exhaust, guaranteeing respect for the environment and for increasingly stringent legislation.


Reliable, robust gearboxes

A range of reliable, robust, sophisticated gearboxes has been developed to match the engine range available on the Fiat 500: one is a mechanical unit (with 5 speeds for the 1.2 and 1.3, and with 6 speeds for the 1.4), the other is of the sequential robotised type, and will be available after the launch on petrol-engined versions.
The mechanical gearbox is very compact and gear-shift manoeuvring is excellent. This was made possible by the reduced inertia of the driven clutch plate and the introduction of new seals. The gearbox configuration is transverse with two cascade shafts, while the speed control is internal, with four selection levels.
The external drive is dual hose type, which filters out engine running roughness and vibration transmitted by the engine to the gear lever. The gears have teeth with extra covering, as well as fifth speed and final drive pairs that are given an extra finish after heat treatment (this improves quiet operation). The gearbox housing is light and absorbs noise efficiently, and has been fine tuned using the Finite Element Method.
The mechanical gearbox of the Fiat 500 has a ‘syringe’ mechanism that prevents the involuntary engagement of reverse.
The Dualogic gearbox is a jewel of mechanical engineering and deserves a separate mention. It will be available after the launch combined with the mechanical gearbox that equips the 1.2 8v and 1.4 16v versions and it features an innovative transmission system. It automates the clutch and gear lever controls by means of an electrohydraulic servo, but maintains all the advantages of a dry clutch and a mechanical gearbox (weight, sturdiness and reliability, low energy consumption).
This sophisticated system improves the performance of the manual mechanical transmission components and increases driving safety because it avoids errors by the driver and prevents faulty manoeuvres of the transmission system.
There are two operating modes: semiautomatic and automatic.
The first adopts the most advanced control strategies to guarantee the best performance. Gears are engaged using the lever on the facia. Because there is no clutch pedal, the device is controlled simply by moving the lever: forward to change up (towards the ‘+’ symbol), back to change down (towards the ‘-‘ symbol). A simple push is sufficient to ensure the transmission makes a fast, accurate gear change.
This is how the Dualogic transmission functions in semiautomatic mode. Most of the electric signals reach the control unit by CAN (Controller Area Network) and can be grouped in two large subgroups. In one, the data from the gearbox area, which make it possible to identify the engagement position, the selection, the clutch, and the operating pressure of the hydraulic kit, as well as the rotating speed of the clutch. In the other, all the signals coming in from the control lever on the tunnel or the levers on the steering wheel (which are optional), that let the driver decide when he wants to change gear, and those from the other systems on the Fiat 500 (for example, the engine and braking system), which help to define the gear change precisely and repeatably. For example, coordination with the engine control unit makes it possible to change up without having to release the accelerator pedal or to automatically increase engine speed when changing down (double de-clutch).
Using these two groups of signals, the Dualogic gearbox can manage gear changes in a comfortable or sporty way, in the manual or automatic mode, interpreting the driver’s needs by analysing the pedal position and the engine speed.
Once the engine on the Fiat 500 is started, any pressure on the brake pedal confirms that the driver is at the wheel, and enables first or reverse to be engaged (on a slippery surface it is also possible to set off in second). And to guarantee safety and prevent incorrect gear engagement, the system engages neutral automatically when a door is open with the engine running. The Dualogic device also prevents errors that might damage the engine or gearbox, by notifying the driver of emergency situations or incorrect manoeuvres with warning lights and beeps.
The automatic mode of the Dualogic system offers two settings on the 1.2 version: Normal and Economy. The Normal setting provides outstanding driving comfort, with brilliant acceleration and gear changes in all conditions. The Economy setting, on the other hand, is used to reduce fuel consumption, while still maintaining outstanding handling and comfort. On the version for the 1.4 16v engine, the two settings are Normal and Sport (with the Sport button on the facia). The Sport setting activates a faster gear change logic that minimises the torque gap and thus makes the car more ‘fun to drive’ for the driver.
In automatic mode, the system recognises the road gradient (by means of a software algorithm) and modifies the gear shift point to ensure the best possible compromise between the driver’s needs, ground conditions and vehicle situation (speed and engine rpm). Another feature peculiar to the Dualogic gearbox is its ability to measure the vehicle deceleration and adapt gear changes accordingly. For example, in semiautomatic mode, and particularly with a sporty driving style, the system changes down when the driver asks for a lower speed to take a corner with more gusto. In automatic mode, the system anticipates the change down so that the driver has the best speed to maintain the level of comfort or fuel economy.
The Dualogic system is the best compromise for drivers who prefer the enjoyment and entertainment of a manual shift, but like to know they can count on the convenience of an automatic.


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© 2011 FIAT S.p.A • P. IVA 00469580013 • Note LegaliCredits