New Fiat 500 In Depth

Page 1: Manifesto
Page 2: In brief
Page 3: Joint effort
Page 4: Engines
Page 5: Gearbox
Page 6: Safety
Page 7: Experiencing the 500
Page 8: Standard features
Page 9: Specifications

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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