Fiesta time at Ford

The new Fiesta borrows some Focus styling cues but retains an individual identity.

Designing a totally new supermini is one of the most challenging experiences for an automaker. The problem is that it has to do so many things better than others have managed—ranging from packaging to lifetime running costs. But for Ford there is an added element to all this: its new Fiesta supermini also had to handle like a sports car. It was Richard Parry-Jones, now Ford's Global Vehicle Development Vice President, who injected the key "no compromise" philosophy into the company in the early 1990s that has been a guide to the creative capability of the company's specialists ever since. In essence, he believed that Fords should be designed and engineered to have outstanding driving dynamics. The philosophy was adopted, and the result has been a series of models that have proved the point, notably the Puma, the Focus, and the latest Mondeo.

The Fiesta was also good, but had become dated in some respects, particularly with regard to packaging, and was certainly due for a major redesign. And that is what Ford has given it.

Martin Leach, Vice President, Product Development, Ford of Europe, is the man who has overseen the program: "We knew that a dramatic improvement in packaging was required—particularly in the rear-seat area. We also wanted to achieve enhanced safety and make the new car very rewarding to drive. We are trying to establish a situation where each new Ford in the mainstream lineup reinforces those that went before it to build a brand momentum, so it was a natural evolution for us to have clear ties in strategy, concept, and looks to the Focus. There is a trend with each new model that they tend to be a little larger than the one they replace. People want more space, and that is occurring in Europe, the U.S., Japan, and the rest of Asia."

A high roof line and long wheelbase emphasize Ford's packaging aims for the Fiesta.

Conscious that the old Fiesta was aging rapidly in terms of market requirements and expectations, Ford expedited the introduction of the new car, said Leach, the program taking about 23 months from design freeze to Job One last November, followed by a gentle production ramp up.

Important though driving dynamics may be, packaging is what's important with the new Fiesta. To some extent, packaging impinges on handling, because instead of the fully independent control-blade rear suspension fitted on the Focus, the Fiesta has a space-efficient twist-beam (with a U rather than a V section) solution to maximize luggage space and probably reduce cost. The result is a 980-mm (38.6-in) distance between the rear strut towers.

The new Fiesta's instrument panel uses very prominent air vents as a styling feature.

The Fiesta is a tall car, with an overall height of 1432-1463 mm (56.4-57.6 in) depending on wheel size, with the driver's H-point 46 mm (1.8 in) higher than the outgoing model's and only 2 mm (0.08 in) lower than the larger Focus. The car was designed to cater to a body range from a 2.5-percentile female to a 97.5-percentile male with particular attention paid to rear space, the car having 76 mm (3 in) more legroom and 59 mm (2.3 in) more knee clearance. A wheelbase extended by 41 mm (1.6 in) to 2486 mm (98 in) makes a major contribution to these improvements. Luggage volume is 284 L (10.03 ft³).

Ford states that the emphasis on packaging was made at the start of the design process, with 22 hard points identified. RAMSIS computer package simulation was used to digitally represent occupant positions. Gear shifting tests in a driveable buck resulted in the shift lever height being raised by 95 mm (3.7 in). An eye-point buck led to the decision to give the car enhanced lines to improve hood sighting for smaller drivers; the Fiesta also has a low belt line. Overall length of the car is 3917 mm (154.3 in) and width 1683 mm (66.3 in).

The 1.4-L Duratorq TDCi engine provides 160 N•m (118 lb•ft) of torque, the figure peaking from 1750 to 2500 rpm. Its common-rail technology comes from Siemens.

A very close second to packaging was driving quality. The benchmarking target for the Fiesta was Ford's Focus. The company says that Focus-style technologies were used to optimize many of its components and systems, including "friction reduction for steering precision and compliance optimization for robust handling." Steering is rack-and-pinion with a fairly quick 15.5:1 ratio and 2.8 turns lock-to-lock. All Fiestas have a leather-rimmed steering wheel; use of the material is to link tactile quality to dynamic quality.

Driving dynamics of any car depend very much on body stiffness. Ford says the new Fiesta is 100% stiffer in global bending at 9559 N/mm (54,600 lb/in) and 40% stiffer torsionally at 607 kN•m/rad (448,000 lb•ft/rad) than the previous Fiesta. Key to this stiffened design is the creation of ultra-stiff mounting points for the suspension and steering systems. The body structure must robustly resist bending in these areas so that the suspension and steering systems operate with full effectiveness. Extensive use is made of tailor-welded blanks, and about 40% of the body uses high-strength steel.

At the front of the car, a rigid subframe is bolted to the main structure onto which a MacPherson strut suspension and steering system are mounted. The subframe, which is quickly installed during assembly and easily replaced in the event of collision damage, helps isolate noise from the main body structure. The struts are designed with offset springs for lateral compensation, reducing suspension friction and improving ride smoothness. Dual-path top mounts separate the forces of the dampers and springs. Front roll stiffness is up by 40%.

Compared to the previous Fiesta, the new small Ford has a body structure that is 100% stiffer in global bending.

The rear suspension is wider by 71 mm (2.8 in) compared to the previous Fiesta. The U-shaped twist-beam profile provides stiffness and reduced weight. It has a lower shear center than the V-shaped beam, helping to optimize roll-steer—a compensating force for toe compliance due to lateral cornering forces—and reduce body roll.

Ford says the level of ride and handling it required for the Fiesta was attained via attention to detail. For example, angled pivot bushings with special voids to aid in longitudinal compliance for ride comfort apply opposing aligning torque to help the suspension system resist lateral forces. Longitudinal compliance while braking has increased by nearly 30%, while rear roll stiffness is up by more than 15%. The rear suspension uses monotube dampers (with sophisticated valving) that are compact to complement overall vehicle packaging. They are placed upright to the outboard edge of the vehicle, but springs are positioned underfloor. Brakes are discs in front, drums in the rear, but an all-disc system may be offered on subsequent versions of the Fiesta.

Safety systems include dual-stage front airbags. There are six airbags available for the Fiesta including side curtains. A "decoupling brake pedal" is fitted to reduce foot and leg injuries in the event of a collision. The system has a two-piece brake-pedal blade that decouples, or delatches, in a severe crash, allowing the brake pedal to drop to the floor. The steering rack is lower on the new Fiesta, and the mounts of the sacrificial crash cans in the bumper structure have been strengthened. The bolt-on lower front subframe has an energy-management role. A cold-rolled steel beam provides side-impact protection.

A twist-beam rear suspension enhances the Fiesta's available trunk space.

Gasoline engine choice for the Fiesta covers four-cylinder, 1.4- and 1.6-L, 16-valve units (carried over from the Focus) and a new 1.3-L 8-valve. Also offered is a 1.4-L Duratorq TDCi common-rail turbodiesel, the first fruit of a cooperative agreement between Ford and PSA Peugeot Citroën. The engine provides 160 N•m (118 lb•ft) of torque, the figure peaking from 1750 to 2500 rpm. Maximum power output is 50 kW (67 hp). EU combined fuel consumption is quoted at 4.3 L/100 km, with target CO₂ emissions of 114 g/km. The common-rail technology comes from Siemens. Individually controlled piezo-quartz injectors facilitate accurate injection timing for better idle quality and improved emissions performance. Oil changes, at 20,000 km (12,500 mi), are the same as for the gasoline engines; the first major service is at 60,000 km (37,500 mi). A 66-kW (89-hp) version of the engine is understood to be under development.

The new 1.3-L gasoline engine has been dubbed a "friction-fighter" for its lightweight, low-friction construction. The engine uses roller finger cam followers, a single overhead camshaft operating eight valves, a roller chain camshaft drive, 6-mm (0.23-in) diameter valve stems for reduced seal friction and weight, and an optimized bore finish and ring-pack design. Engineered for fully stoichiometric performance, it does not need extra fuel for cooling the exhaust system and catalytic converter under high-demand conditions. This allows the engine to retain optimum fuel efficiency by maintaining the ideal gas-to-air combustion mixture, according to Ford. The engine returns an EU combined fuel consumption of 6.2 L/100 km, with target CO₂ emissions of 147 g/km. Power output is 50 kW (67 hp).

All engines drive through a five-speed manual gearbox.

- Stuart Birch