PANELS AND FRAMES

Description 72

INTRODUCTION

The topics are covered with particular attention to the new technical features required for passing the various tests introduced by new legislation. The descriptions and operating information provided are limited to a discussion of principles, rules and minimum precautions.

For information on repair methods and vehicle specifications, see the specific sections on repair procedures.

Aerodynamics

The styling of the new car is designed to reflect great personality and originality and improves on the attributes of roominess, practicality and sturdiness achieved by previous models.

The front, sides, rear and underbody were developed with particular attention to aerodynamics and allow outstanding drag coefficient values. The following values are an example:

Three door version

- drag coefficient CX = 0.32

- drag coefficient for area CX x S = 0.6528

Five door version

- drag coefficient CX = 0.325

- drag coefficient for area CX x S = 0.663

These values are the result of road testing and measurements carried out in a Fiat wind tunnel.

These results contribute to the noiselessness of the vehicle and significantly reduce wind noise. They also allow fuel saving.

Safety

The main aim of car manufacturers is definitely the total safety of the driver and passengers.

To adapt the vehicle to highly demanding European and international market regulations, the new Fiat vehicle was designed with great attention to detail in order to achieve an optimum response in all situations.

Passive safety

A vehicle''s passive safety is the collection of technical and product solutions designed to protect the occupants of the vehicle in the case of an accident.

The search for excellent performance has led to the introduction of design and construction solutions on the new vehicle that represent the state of the art in the field of passive safety.

The safety features guaranteed by the vehicle stem from the thorough integration of the structural components, the high number of specific devices that make up the occupant protection system and the special devices used in the design of the interior and exterior components.

The occupant protection system

The vehicle is equipped with a basic occupant protection system on all trim levels composed of:

- front Air Bag protection system including dual (driver and passenger) front Air Bags with a dual activation system;

- front belts with pretensioner and load limiter;

- electronic Air Bag disabling system (my car).

A side protection system is also available as an optional extra featuring:

- two Bags on the front seats that guarantee protection for the chest and pelvis;

- two head bags housed in the side members under the roof that guarantee protection for the head against highly intrusive objects.

For more information on the Air Bag system see.

See descriptions 5580C AIR BAG SYSTEM

In addition to passenger safety, the New Punto is also conscious of child safety and pedestrian safety.

The child safety system includes all those devices that offer the best protection currently available such as isofix mountings on the rear seats and the inhibition of the passenger air bag directly by the on board computer.

The solutions adopted in the design and manufacture of the seats, the dashboard and the interior panels and fittings increase the degree of passive safety of the vehicle.

For more information on these topics, refer to the specific chapters.

Resistance to impacts

All the features relating to Passive Safety have been developed in order to offer the maximum protection for the occupant in all possible impact situations at high speed:

- frontal impact

- rear impact

- side impact

- roll over.

The behaviour of the bodyshell in crash tests has more than adequately satisfied the international safety standards.

Pedestrian protection

The style of the front part of the vehicle has been developed taking into account the protection of pedestrians as required by the most recent international legislation. The shapes are smooth and rounded and there are no unsafe projections for the safety of pedestrians. The ample surface area of the bonnet minimizes the risk of contact between pedestrian''s heads and the rigid front pillars.

The most rigid components are located inside the engine compartment a suitable distance away from the bonnet in order to allow the bonnet skin to absorb the energy forces of the impact with the pedestrian''s head.

Torsional and bending strength

The vehicle''s great torsional and flexural rigidity ensure good properties of passive strength and also offer a number of benefits:

- low noise due to fewer vibrations;

- no creaking from the trims;

- better handling by maintaining the correct suspension angles and thus an absolutely controlled drive for a sensation of stability and comfort in general,

- greater ability to withstand breakages caused by using the vehicle over particularly uneven road surfaces;

- sensation of vehicle compactiness;

- to ensure long-term overall vehicle quality.

Torsional strength on 3 door version (torsion deformation diagram)

Torsional strength figures

Body with bonded windscreen: 111700 daNm/rad

Bending strength on 3 door version (bending deformation diagram)

Bending strength figures

Body with bonded windscreen: 1120 daN/mm

Torsional strength on 5 door version (torsion deformation diagram)

Torsional strength figures

Body with bonded windscreen: 95500 daNm/rad

Bending strength on 5 door version (bending deformation diagram)

Diagram showing deformation due to bending

Bending strength figures

Body with bonded windscreen: 1040 daN/mm

PROTECTION OF THE BODYSHELL

Anti-corrosion design

The bodyshell has been designed to withstand environmental conditions in the most severe markets such as Central Northern Europe where salt is used on the roads to prevent freezing.

Design features have been introduced with this in mind to guarantee complete accessibiity of the bodyshell to the protection and painting processes (in particular the anti-rust treatments and cataphoresis) and ensuring that all the elements are the correct shape to prevent any possible dampness forming in the internal structures.

This includes the design of the panel joins (shape and dimensions) in order to make them suitable for the sealing operations, which is essential both in terms of water tighteness and sound inslation of the vehicle.

A fundamental part of the design is also the choice and usage of galvanized panels for all elements of the bodyshell exposed to the potential risk of corrosion.

Galvanized panels

The zinc deposited in a continuous layer on the surface of the panel constitutes the first line of defence against corrosion of the steel. The zinc layer acts as an active chemical protection for the steel, known as a sacrificial layer, that combines with the subsequent protective systems to guarantee outstanding long-term corrosion-proofing.

The galvanizing of the panels takes place directly through two different technological processes, both capable of ensuring constant thicknesses of zinc with a high standard superficial finish:

- Galvanizing: the panel is immersed in a solution of zinc salts where a layer of pure zinc is deposited through the electrolytic effect; the normal thickness of the zinc deposit is 8 - 10 micron.

- Hot galvanizing: molten zinc is deposited on the panel due to the effect of heat. In this case too the normal thickness of the zinc is 8 - 10 micron, but thicknesses of up to 20 micron can be reached using this process and it should be used for the parts most exposed to corrosion.

The two processes allow galvanizing on both sides of the panel.

It is therefore possible to produce simultaneous protection for both the inside and the outside of all panels and, in particular, protection of the surfaces in contact with several elements welded together.

The bodyshell of the vehicle comprises panels galvanized on both sides for 90% of its weight.

In particular, all the parts that make up the chassis, most exposed to corrosive agents, are 100% galvanized.

Of these, the structures defined as safety structures, such as the suspension mountings and reinforcements for the seat belts are made from panels with a high thickness of zinc, up to 20 micron.

The body is made entirely from galvanized panels 8 micron for the doors, bonnet, boot lid, side panels, wings, roof.

The exception is some of the inner parts of the passenger compartment because there is no risk at all of oxidation such as, for example, the dashboard mounting brackets.

Anti-corrosion test

All the anti-corrosion provisions made have been subjected to laboratory tests and they have performed well in accelerated tests on vehicles carried out in special test areas where the most stringent conditions of the central north European markets have been reproduced.

Anti-corrosion goals

The anti-corrosion provisions made make it possible to satisfy the following anti-corrosion guarantees:

- 3 years of the vehicle''s life without cosmetic corrosion points

- 8 years of the vehicle''s life without panel perforation in the most harsh Northern European climates.

In addition, the protective package made up the medium-high thickness galvanizzed panels plus cataphoretic treatment of the entire structure makes it possible to comply with the European regulations concerning safety features (10 years of the vehicle''s life without structural weaknesses).

Painting

Specifications of the painting cycle

The aim of painting the bodyshell is to:

- protect the sheet metal against corrosion due to exposure to environmental effects;

- achieve high levels of gloss and colour richness and maintain them in time.

Before being painted the bodyshell undergoes a pre-treatment process known as bonderization during which an initial degreasing stage is followed by a phosphating treatment.

The latter forms a crystalline layer of phosphate which make up the base on which the subsequent painting layer is applied through cataphoresis.

Painting through cataphoresis is a fundamental treatment for the protection of the structural elements.

It allows the paint to be deposited in areas of the bodyshell that would otherwise be inaccessible such as the internal box structures.

The process takes place through immersion in an electrically insulated vat containing an acqueous solution of paint product.

The solution is negatively charged whilst the bodyshell is positively charged. During immersion, a layer of paint is deposited (22 microns on horizontal parts and 20 microns on vertical parts) that can be adjusted by altering the bath voltage, the bath temperature and the length of time the body remains in the solution.

The body then undergoes a process of stoving in an oven at 160° for 20 minutes.

Heat bonded materials are then applied to the prepared body and then all the joints between the body panels are sealed to prevent corrosive agents leaking through. An abrasion-resistant coating is then applied to all areas exposed to gravel from the road.

The body is now prepared by adding a primer coat (30 microns thick) before undergoing a further stoving cycle in the oven.

Lastly, the aesthetic finish is applied comprising a layer of enamel base coat (colour) followed by a clear resin coat with very good resistance properties to outside agents (humidity, the sun''s rays) and the final baking in the oven.

Environmentally-friendly, water-based enamels are used at the production plant.

The table illustrates the painting process for the vehicle.

Bodyshell painting cycle

Identification

The vehicle coloru range includes:

- pastel colours;

- metallic colours.

Both produced through the application of a pastel or metallic base coat and clear resin (double layer).

The vehicle colour type and specifications are shown on the identification plate that shows the following information.

A - enamel supplier (coloured base)

B - colour name

C - colour code

D - type of product to be used for touching up and painting in the event of service operations

Recycling of materials

Main specifications

According to EEC ELV (End of Life Vehicles) directives, all metallic and non-metallic parts must be recovered from the vehicle and reused, 80% to produce new material and 5% for recovered energy. Nowadays, some 75% of a vehicle''s weight is made up of metal that can easily be recovered by melting when different metals can be separated by heating to their different melting points. All the remaining part of the vehicle, amounting to 25% by weight, must be recovered before this stage. The solution to the problem of recycling plastics is resolved at the design stage: the possibility of re-using the material on future components must be assessed at this time:

The aims to be considered at the design stage include:

- ease of component disassembly;

- choice of noble materials in the recyclable polymer chain (giving priority to parts made up of a single family, e.g. PP).

Recycling does not allow the production of a part that is the same as the original part because the material may not be able to guarantee the necessary levels of reliability or it may not be financially viable.

Plastics may be recycled in a cascade pattern. For example:

- insulating material for the building industry is obtained from seat padding;

- the material used to line the wheel arches is obtained from the bumpers and then goes on to produce sound-proofing elements. In the end, it becomes a fuel for energy production.

This model has been designed to ensure that all its plastic and elastomer parts (rubbers) weighing over 50 grams are marked with coded symbols to identify the material during recycling and also to ensure that all its components are recyclable.

In particular, the impacts that could be exerted on the environment both during the life cycle of the product and during the scrapping stage are already analyzed during the design stage. In some cases the choice of materials has been made using an innovative evaluation system known as L.C.A. (Life Cycle Assessment) which makes it possible to assess the effects on the environment globally, taking into account not only the engineering and industrial specifications of the materials, but also the environmental critical areas during the production of the raw materials during usage and at the end of life.

Great emphasis has been placed for this model on improving its recyclability: technological solutions in single materials have been favoured and the polymer families present have been further reduced.

The recycling therefore involves three successive generations of vehicles contributing to savings in raw materials. Other materal reuse processes are also being examined outside the motor industry, following the lead taken by the F.A.Re (Fiat Auto Recycling) partnership in the Eighties and Nineties.

Another important point to note concerns the use of heavy metals in the motor industry. The metals in question are hexavalent chrome (Cr6), Mercury (Hg), Cadmium (Cd) and lead (Pb). These are banned (Cr6) or permitted only in tiny amounts when their use must be indicated by labelling or by including information in the documents supplied with the vehicle.

The tables in the chapter "GENERAL INFORMATION AND TECHNICAL DATA - OPERATING DATA" show symbols for and descriptions of recyclable materials present on the vehicle. This is to ensure that the best available products are used to wash the interior, paint plastic parts and carry out repairs, bonding etc. The aim is to avoid the possibility of damage by using incompatible products. Labelling also allows organic materials to be selected on the basis of their chemical composition. During service, it is also advisable to separate materials on the basis of their composition to ensure that they can be recycled more easily.

Diagram showing the reuse of recycled materials

Labelling of part of the recyclable material

TYPICAL BODYSHELL MEASUREMENTS

Adjustment of moving parts

Measurements for the adjustment of the moving parts

To facilitate and verify mobile part disassembly operations, the existing gaps are shown (in millimetres) to allow appropriate adjustment.

The adjustment procedure is described in the sections describing mobile part removal and refitting procedures.

VIEW OF THE VEHICLE (THREE QUARTERS FRONT) WITH THE POSITION OF THE MEASURING POINTS FOR THE GAPS BETWEEN THE MOVING PARTS

MEASURING POINTS FOR THE GAPS BETWEEN PARTS FROM 1 TO 5

MEASURING POINTS FOR THE GAPS BETWEEN PARTS FROM 6 TO 9

VIEW OF THE VEHICLE (THREE QUARTERS REAR) WITH THE POSITION OF THE MEASURING POINTS FOR THE GAPS BETWEEN THE MOVING PARTS

MEASURING POINTS FOR THE GAPS BETWEEN PARTS FROM 10 TO 14

Application of sealant

VIEW OF THE VHEICLE WITH SEALANT APPLICATION AREAS ILLUSTRATED

Detail showing sealant application in areas 1 to 3.

Typical measurements

Diagram for checking underbody

This chapter shows the specified vehicle dimensions to ensure the best results are achieved when carrying out repair operations.

The comparative dimensions, expressed in millimetres, may be subject to differences (about 2 mm). Repairers must use their experience to decide whether this is due to impact damage or manufacturing tolerances.