2005 Ford Five Hundred Driving Dynamics
"If I had to use one word to describe the experience of driving the all-new Ford Five Hundred, I would say 'smooth.' With any of the powertrain combinations, you feel smooth acceleration, confident cornering on nearly any type of surface and firm, predictable braking - all in a quiet, comfortable environment. It's a very refined approach to driving enjoyment."
- Jan Vulcan, Chief Nameplate Engineer
DEARBORN, Mich. Nov. 26, 2003 - The all-new Ford Five Hundred adds innovative features to a strong, responsive chassis, creating a unique, rewarding driving experience that's designed to reinforce the driver's feeling of confidence and command of the road.
It starts with Five Hundred's two new transmissions - an electronically controlled continuously variable transmission and an all-new six-speed automatic - that feature wide ratio spans with a low initial gear ratio for superb off-the-line performance and acceleration without sacrificing fuel economy.
It continues with available all-wheel drive, electronically controlled to react quickly and seamlessly whenever traction is compromised. The system can respond within 50 milliseconds to shift torque to the axle with the best traction - in many cases without the driver even knowing it was activated.
And Five Hundred's command seating position - unique for a sedan - gives the driver an exceptional view of the road.
Engineers drew on best practices from throughout Ford Motor Company to craft the confident ride and handling that help define the new Ford Five Hundred. These include Volvo chassis engineering, Ford's proven, updated Duratec 30 V-6 engine and the all-new continuously variable transmission developed with joint venture partner ZF-Batavia.
But the sum must be greater than its parts. So to ensure that all came together into one high-quality, dynamic package, predictive modeling was used in the design process. Five Hundred's engineering team also incorporated new, powerful on-board electronics and lightweight materials to ensure the new Five Hundred sedan offers a nimble, responsive, sure-footed ride.
Five Hundred's major features include:
An all-new, continuously variable transmission - marking the auto industry's
highest-volume CVT application
An all-new six-speed automatic transmission that offers a wider gear ratio span than competing four- or five-speed designs, resulting in better acceleration and fuel efficiency
An improved Duratec 30 3.0-liter V-6 engine, complete with electronic throttle control and delivering 200 horsepower and 200 foot-pounds of torque with less noise and vibration. Combined with Five Hundred's new wide-ratio transmissions, the Duratec engine delivers superb acceleration
Available all-wheel drive and traction control that enhance grip and performance on all road surfaces
A sophisticated chassis design, adapted from Volvo, that offers high torsional stiffness for crisp handling and a smooth ride
Dual-piston aluminum front calipers that contribute to confident braking performance
New Transmissions Enhance Economy, Performance
The Five Hundred sedan - along with the Freestyle crossover - represents Ford's highest-volume application of continuously variable transmissions and is expected to help make Ford the leader in CVTs. These transmissions will be standard on the Five Hundred SE series and on all-wheel-drive versions of the SEL and Limited series.
"The beauty of a CVT is that no matter what speed you're driving, it will always seek out optimal torque," said Ray Nicosia, manager of vehicle engineering for Ford's North American cars and family vehicles. "That's why it feels so responsive - you're never out of the torque band."
Continuously variable transmissions offer several key advantages, including improved fuel economy and an enhanced feeling of performance, over traditional "step" automatics.
Both of these advantages stem from the CVT's wider ratio span - the difference between the transmission's highest and lowest gear ratios. Five Hundred's CVT has an overall ratio of more than 6-to-1. That compares to 4-to-1 for a typical automatic.
The lowest gear ratio - the equivalent of first gear on an automatic transmission - multiplies engine torque to launch the vehicle from a standing start. The Five Hundred's low ratio ensures stronger off-the-line acceleration that will delight drivers.
The highest gear ratio - equivalent to top gear on an automatic transmission - is used primarily for cruising at steady speeds, maximizing fuel economy. The CVT is expected to deliver better city/highway mileage than a conventional four-speed automatic.
The CVT also allows the Five Hundred's relatively small, efficient V-6 engine to perform like a bigger engine, because it precisely matches the gear ratio to engine speed to answer the demands of quick acceleration, a steep hill or other loads.
The new ZF-Batavia CVT also is designed for ease of ownership. Maintenance recommended at 60,000 miles includes draining and refilling the transmission fluid - no filter change is necessary - and under normal use, the drive belt is good for the life of the vehicle.
The CVT is not the only transmission for the new Five Hundred. Capable of delivering similar performance and fuel economy, an Aisin AW six-speed automatic transmission is standard on front-wheel-drive versions of the Ford Five Hundred SEL and Limited series. The Aisin six-speed offers a ratio span nearly identical to the CVT, but in a premium "step" automatic.
The electronically controlled six-speed "learns" the driver's patterns and adapts shift points to optimize performance or fuel economy. In "low" range, the transmission controller enables engine braking to assist with hill descents or other demands.
Maintenance also is minimal, with the six-speed transmission's fluid rated for 10 years/150,000 miles.
While final fuel economy numbers won't be available until closer to the launch date, Ford expects the new Five Hundred to be among the most efficient in its class.
Electronic Brains Do More - And More Quickly
This level of performance is made possible in part by powerful new powertrain electronics. The new Black Oak controller uses PowerPC machine language and floating-point calculations to perform more tasks more quickly. It monitors data from all of the vehicle's sensors, transmitted along an information highway called a Controlled Area Network (CAN) bus, and reacts accordingly.
Powertrain engineers took advantage of this capability and designed a special calibration for times that CVT-equipped vehicles drive downhill. The system detects that the vehicle is on a descending grade and adjusts engine speed and transmission ratio to hold a steady speed. And, like most powertrain functions, this is seamless to the driver.
This type of calibration, as well as design of the accelerator pedal components, provides the familiar feel and response of a traditional mechanical throttle linkage while offering the performance advantages of electronic throttle control.
All-Wheel Drive Provides Confident Traction
The CVT is available with an optional electronically controlled all-wheel-drive system that delivers optimum performance whether on dry, wet or snow-, mud- or sand-covered roads.
Normally, the vehicle functions in front-drive mode only. But like the vehicle's other electronic components, the controller continuously monitors information flow along the CAN bus to determine whether AWD is needed. It can react within 50 milliseconds to distribute virtually all of the available torque to the rear wheels.
The all-wheel-drive system begins at the continuously variable transmission, where a Volvo-built power transfer unit, similar to one on the Volvo XC70 wagon, siphons off torque being sent to the two front wheels and delivers it to the drive shaft that leads to the rear wheels.
This program represents Ford's largest-ever passenger car application of all-wheel drive, and places the automaker alongside leading niche- and luxury-vehicle manufacturers in this technology.
"The Volvo technology was a great enabler for us, because it is much more difficult to package all-wheel drive in a passenger car than in an SUV or a truck," said Phil Kurrle, design and release supervisor for Ford's family car powertrain subsystems. "Through Volvo's leadership, we now have access to lightweight and compact all-wheel-drive components that have proven beyond question their reliability."
Because the system is lightweight and has relatively few moving parts, it carries a negligible fuel economy penalty.
Haldex a Smooth Operator
The Sweden-built Haldex coupler works through a combination of hydraulic and electro-hydraulic activation of its internal clutch pack.
When the vehicle is in motion, the drive shaft is in motion as well, driven by the CVT-mounted power transfer unit. If the drive shaft turns more quickly than the output shaft at the rear of the Haldex, oil flow is generated, which in turn produces hydraulic pressure in the Haldex coupling.
This increased hydraulic pressure pushes the clutch plates together, transmitting drive shaft torque through the Haldex unit to the rear wheels.
Because a mechanical pump creates a natural pulsing pressure, the Haldex system incorporates three pistons designed to operate out of phase with each other, evening out pressure waves for seamless, smooth actuation. This is another example of the way vehicle engineers used technology to achieve a refined driving experience.
The Haldex unit also includes an electro-hydraulic pump that offers yet another advantage: If the electronic controller senses impending wheel slip, it can utilize hydraulic pressure from the pump to pre-load the clutch pack, causing it to engage more quickly. This, too, contributes to smoother performance.
These systems are designed to quickly apportion torque between front and rear - up to 100 percent in either direction as needed - to avoid wheel slip.
"It works very quickly," Kurrle said. "Within about one-seventh of a turn of the front wheels spinning, the rear is getting power. This is much quicker than a viscous coupler could achieve."
The system also releases just as quickly, avoiding binding or wheel skid once traction improves.
An optional traction control system - standard with all-wheel drive - allows progressive braking to be applied to each wheel within 100-150 milliseconds of the onset of wheel slip. This precise braking adds side-to-side torque transfer capability.
"With the two systems working together, you can send torque to the individual wheels that have traction," Kurrle said.
Traction No Matter What
The CVT adds its own strengths to the all-wheel-drive system. Because it offers such a broad gear ratio range and automatically optimizes engine torque for variant conditions, the all-wheel-drive system always has plenty of torque on hand to plow through deep snow, mud, sand or other challenging conditions.
All-wheel drive offers advantages on either dry or wet pavement. Because the system can transfer torque quickly and smoothly away from the front wheels, it helps reduce the type of understeer often associated with front-wheel-drive vehicles.
Traction control adds security to the driving experience by reducing engine power or selectively applying braking to any wheel as needed to enhance traction and steering response. By tapping into sensors at all four wheels, the system even can compensate when the car is being driven with a space-saver spare tire and maintain all-wheel-drive functionality.
The traction control system seeks to reduce wheel slip in vehicles with front-wheel drive by first retarding engine spark; then, if necessary, reducing fuel flow. Finally, it engages selective braking as needed to restore traction. In all-wheel-drive applications, the system uses brake intervention immediately.
"Controllability and stability are important considerations in the way we designed this system," Kurrle said.
Duratec 30 Engine Refined
Ford's proven, highly efficient, 3.0-liter, 24-valve Duratec 30 V-6 has shown to be an ideal match for the Five Hundred's new CVT powertrain.
First introduced in 1997, the Duratec 30 has undergone many improvements, including several unique to this program.
Even the Duratec manufacturing site is all-new - Ford's Cleveland Engine Plant Number One has been converted to employ leading flexible manufacturing techniques that provide quality improvements and allow rapid response to market demand.
In addition to delivering excellent fuel economy, the newly refined Duratec 30 V-6 provides the Ford Five Hundred with outstanding emissions performance.
"Our emissions level will meet the federal Tier II, Bin 5 definition, which is equivalent to the California LEV II standard," said Kim Jackson, powertrain supervisor. "In particular, the vehicle will have very low evaporative emissions. They are just 25 percent of the current allowable federal standards." Tier II, Bin 5 is also twice as clean as the ULEV standard.
This is achieved using less-permeable materials in the fuel system, new charcoal canister technology to capture evaporative emissions and upgraded connectors for the fuel system and vapor line to reduce the amount of gases that escape. An onboard vapor recovery system captures gasoline fumes during fill-up, routes them to a storage canister and releases them to the engine to be burned.
The electronic returnless fuel system also helps improve fuel economy and prevent vapor lock, which can be caused by hot fuel lines.
Noise, vibration and harshness have been reduced in the Duratec 30 as well. Computer technology helped engineers design a new dual-mass, dual-mode frequency damper that mounts to the crankshaft at the engine's front end. It reduces both torsional and bending vibrations that could produce noise.
Computer optimization also was used to create the complex shape of the front engine cover, featuring "constrained layer damping." This sandwich of materials absorbs frequencies that might otherwise generate unwanted noise.
Further engine NVH refinements include:
Application of the industry's first direct-drive water pump
Use of optimized mounts, including two hydro-mounts for the engine and two roll-restrictor mounts for the transmission, for improved system stiffness
Use of quieter magnesium cam covers
Designed-in main bearing clearances that are 6-8 microns tighter for reduced vibration
Application of an integrated air-fuel module with extensive ribbing for added stiffness
Incorporation of a resonator in the mass-flow induction system to reduce intake sound at key frequencies
In addition, the engine and transmission are joined by bolts on the engine and by the structural cast aluminum oil pan, contributing to overall powertrain stiffness. By tightly controlling powertrain movement, engineers could tune the engine hydro-mounts to absorb most remaining vibration frequencies, limiting the amount of noise reaching the passenger compartment.
Ease of Ownership
In addition to smooth, quiet performance, the powertrain was developed to be low-maintenance. To ensure durability and ease of maintenance:
The CVT doesn't require service for its first 60,000 miles.
The six-speed automatic transmission doesn't require a fluid change until it has logged 150,000 miles.
Platinum-tipped spark plugs, coil-on-plug ignition and plug wires are rated for 100,000 miles of normal use.
Chassis, Suspension Key to Ride, Handling
Several factors contribute to exceptional ride and handling. The chassis must be stiff to resist bending and twisting forces, and the suspension must allow long travel to absorb a wide range of road irregularities. Damper, spring and bushing rates must be matched to balance ride quality with precise steering. And tires must provide good grip and quiet operation under all driving conditions.
The stiff suspension design for the all-new Ford Five Hundred was adapted from the Volvo P2 platform and optimized in each of those key areas using computer-aided engineering modeling.
"Stiffness is a big player in ride and handling," said Nicosia.
Five Hundred also offers generous total suspension travel - 3.5 inches of jounce and 4 inches of rebound travel.
"That amount of suspension travel lets you tune the shocks a little bit more," Nicosia said. "You can create a more absorptive suspension system for a more comfortable ride."
Rear Suspension Plays to Strengths
The multi-link, independent rear suspension assembly is built on a stout, U-shaped welded-steel subframe that offers exceptional torsional stiffness. The subframe's resistance to shaking, bending and other movement under road impact allows shock absorbers, springs and bushings to do their jobs better.
The rear suspension arrives fully assembled, other than tires and wheels, from the Chicago supplier park near Five Hundred's final assembly facility. This helps ensure efficient production and manufacturing consistency.
The rear suspension plays a critical role in steering feel and overall chassis response. During heavy braking, it is designed to "dial in" a bit of toe-in, which helps retain steering stability. Toe-in measures how much the front part of two opposite wheels point toward the center of the car. It generally is associated with front suspension geometry, where the right amount of toe-in contributes to quick steering response. This precise but forgiving design at the rear of the Five Hundred reinforces the driver's feeling of control whatever the circumstance.
For additional chassis stiffness in the all-wheel-drive platform, which carries the extra load of a rear differential, the engineering team added a small lateral brace that joins the two sides of the subframe.
Lower control arms on all-wheel-drive models are made of hydroformed steel and are very stiff to resist both lateral and longitudinal forces. Lateral stiffness in the lower control arms is one of the most important factors affecting handling response. Hydroforming ensures these critical parts provide exceptional strength for their weight.
Weight is less of a concern in front-wheel-drive versions of the car, so stamped steel lower control arms are employed. The suspension knuckle is made from cast aluminum.
Bushings Provide Smooth Sailing
The stiff control arms are mounted with tuned suspension bushings that absorb fore-aft forces, like those generated by road seams and sharp bumps. A soft bushing at the front end of the trailing link also soaks up longitudinal shocks.
The attention to ride and handling is evident in the rear suspension, which uses 30 different bushings - each designed for its specific task - and one ball joint located at the point where the upper control arm meets the aluminum suspension knuckle.
"With suspension geometry optimized, bushings can really improve ride and handling - and customer satisfaction," Nicosia said. "Computer analysis helped us determine the characteristics we wanted from each bushing, and new manufacturing techniques let us achieve these characteristics."
One critical rear subframe bushing is the front mount of the upper control arm. It incorporates a steel central tube surrounded by a rubber ring, which has voids cast into it toward the front and rear of the vehicle. This asymmetric design offers less resistance to longitudinal forces - up to 6 millimeters of total recession - while providing firm control in other directions. It is mounted into a recess in the steel subframe.
In all-wheel-drive models, the rear subframe is joined to the chassis by four isolated mounts to prevent vibrations from reaching occupants. Structurally strong shear-style brackets provide crash strength and stiffness.
Front-wheel-drive versions of the rear subframe are hard-mounted to the body.
Innovative, Self-Leveling Shocks
One area where the Ford rear suspension differs from the original Volvo design is in placement of the rear shocks. The new design is "coil-on-shock," which puts the shock right in the center of the coil spring. The reduced offset allows forces to be channeled more quickly and directly, while limiting twisting or lateral forces that could bind the shock and induce a harsher ride.
Unique to all-wheel-drive versions are the Nivomat rear shocks from Sachs. These provide load-leveling without a host of moving parts. Internal shock valves sense ride height and use energy from the vehicle's motion to increase hydraulic pressure and raise the shock to the desired ride level.
In a typical scenario, heavy luggage or golf bags are loaded into the Five Hundred's trunk, pushing the rear of the vehicle down slightly. As the car is driven, the shocks quickly "pump up" to the necessary pressure, and the Five Hundred's original ride level is restored - all in about the time it takes to leave the hotel or golf course parking lot.
The system ensures that if the sedan is ever taken off pavement with a fully loaded trunk, it will maintain optimal ride height. The all-wheel-drive sedans ride almost an inch higher than front-wheel-drive versions.
Bump-Taming Front Suspension
The front suspension uses MacPherson struts with rearward-facing L-arms.
"This design is important for a couple of reasons," Nicosia said. "It gives you the maximum amount of room in front of the suspension to manage crash energy. It also gives you the ability to tune the front suspension for responsive steering and a smooth, comfortable ride."
To ensure an even ride, front and rear spring rates are tuned to respond the same way to a bump in the road, even when they carry different loads. That means the vehicle stays level while the shock absorbers damp oscillations and body movement.
As with the rear suspension, individually tuned bushings play a critical role. Final bushing rates were determined through a combination of CAE modeling and real-world ride testing.
One key bushing is located at the rear of the lower control arm. This "hydro bushing" uses oil-filled internal chambers to damp road forces before they can reach the passenger compartment. "It acts like a small shock absorber," Nicosia said.
A large bushing at the top of the MacPherson strut mount is tuned not only to resist vertical or axial movements that occur as a result of uneven surfaces, but also to resist side deflection to maintain a crisp steering feel and fight front-to-rear movement in support of firm braking.
Tires a Perfect Match
Tires are an important component in tuning ride and handling. Seventeen-inch wheels with P215/60R17 Continental tires are standard on the Five Hundred, with 18-inch wheels and P225/55R18 Pirelli tires standard on the Limited series.
The 17-inch tires are designed to offer a blend of ride comfort, quietness, plush rolling feel and good steering response. The 18-inch Pirellis provide a bit more steering feel and a sportier ride, without excessive noise or harshness.
Both brands also offer solid performance in rain and snow.
The rack-and-pinion steering system is tuned for relatively light effort and reasonably quick response, with a steering ratio near 16-to-1.
"You don't have to turn the wheel very far to go around a tight corner in the city," Nicosia said. "About 180 degrees of movement is all you normally will ever need, even for tight turns. This helps reduce driver fatigue because you're not constantly cranking the steering wheel."
Steering effort also is important.
"People like a steering effort that builds up in a linear fashion as you turn the wheel," Nicosia said. "That helps you judge where you're at when the wheels come back to center. You always want the steering wheel to generate some response - for example, in on-center steering you should get steering response before you move the steering wheel 5 degrees. But it's not so touchy that it's hard to drive in a straight line."
Variable power assist wasn't needed to make parking easier - as can be the case with heavier trucks and sport utility vehicles.
However, there's a fine line between steering that feels light and steering that feels numb. Five Hundred finds the perfect balance.
"Because this is a family car - not a sports car - it doesn't need a real heavy feel," Nicosia said. "But it does offer direct feedback to the driver without wearing out your arms."
The steering column is torsionally very stiff. By reducing vibration, this improves both steering response and the feel of the steering wheel in the driver's hands. It also rapidly and directly transmits the driver's input from steering wheel to steering gear. There's little wind-up in the system.
"When people feel like the vehicle is responding intuitively to what they're doing, it lowers the stress and fatigue of driving. They're not always fighting the vehicle," Nicosia said.
Braking feel and response are crucial to the confident driving experience that engineers sought for the Five Hundred. They achieved this by maximizing the size of the four-wheel-disc brake rotors, using dual-piston aluminum calipers on the front brakes, selecting high-friction brake pad materials and fine-tuning the brake system components.
The standard anti-lock braking system improves performance on slippery surfaces, and electronic brake-force distribution continually optimizes balance between the front and rear brakes across the range of road surfaces and vehicle load conditions.
New Brake Pads - More Friction, Less Dust
Five Hundred brake engineers set out to develop a new Ford standard for brake pad performance.
Pad material directly affects braking feel and performance. Until recently, the quest for shorter stopping distances and superb feedback meant accepting dirty wheels because of high levels of brake dust associated with high-friction pad materials.
The Ford Five Hundred takes advantage of new low-metallic pad materials high-mu levels - "engineer speak" for high friction - to achieve strong, reassuring brake performance while generating far less dust than other pads with comparable friction.
New Front Calipers Give Quicker Response
The front brake calipers are made from cast aluminum and use two pistons on each wheel - a common feature in high-performance and sports cars.
The aluminum calipers weigh 10.8 pounds less than cast iron, single-piston calipers of comparable size. In addition, they deliver the stopping benefits of the dual 45 millimeter pistons and heat-shedding properties of aluminum.
Spreading the braking force over two pistons reduces uneven lining wear and promotes even wear of the rotor, enhancing durability and reducing vibration.
There's a dynamics benefit, too.
"By using two smaller pistons, we achieve more precise control of the piston movement," said Joe Kurcz, braking supervisor for the Ford Five Hundred. "We are can keep the brake pads closer to the rotors when they are not in use. That means there's less brake pedal travel before you feel the initial bite of the pads against the rotor. This improves braking feel and driver confidence."
Because only a small protective rubber piston "boot" is required, pistons don't pull away as much from the rotor when the brake is released, allowing the pads to remain closer to the rotor for quicker activation when braking is needed. To ensure that the brakes retain their feel and performance during repeated, hard stopping, the brake pistons use a combination of phenolic coating - which helps prevent heat transfer to the brake fluid - and stainless steel. The majority of heat generated during braking is absorbed by the rotors and dissipated.
The parking brake is integral to the rear caliper, rather than employing a separate parking brake drum. The parking brake cable actuates a ball-and-ramp cam in the rear brake, which mechanically applies the brake pads.
Large Wheels Mean Larger Rotors
The 17-inch standard wheels on the Ford Five Hundred allowed brake engineers to specify a large rotor size. The front brake discs are 315 mm (12.4 inches) in diameter by 28 mm (1.1 inches) thick. The rear brake discs are slightly larger - 330 mm (13 inches) in diameter by 11 mm (0.43 inches) thick.
The front rotors are larger than those on the Ford Crown Victoria. The front rotors offer 408 centimeters2 (63.3 inches2) of swept braking area. The rear rotors have 380 centimeters2 (58.8 inches2) of swept area.
Brakes are Stiffer, Too
Total system stiffness and a reduction in wasted pedal travel are important to achieving a premium, confident braking feel.
"We made a breakthrough on the overall pedal stiffness," Kurcz said. "We benchmarked pedal force versus deflection of the best vehicles on the market. Based on our findings, we made significant increases in stiffness within the brake pedal assembly, which directly relates to improved pedal feel."
One particularly important vehicle design element that also helped brake system engineers achieve the feel they wanted was the very stiff dash panel designed into the Five Hundred.
"Since the brake pedal assembly attaches to the dash panel, the reduced flex in this critical area results in reduced pedal travel at any given brake force, a direct improvement to pedal feel and braking confidence," Kurcz said.
Another key to achieving the right braking feel was reducing "lash," or wasted movement in the system. The team tightened up several tolerances, including the actuating rod in the master cylinder and bushings in the brake linkage.
Braking force also often is wasted in the flexible brake lines. But the Five Hundred addresses this through use of a premium material that expands minimally under pressure.
A number of tests helped engineers focus on results they wanted. One repeatedly measured pedal travel and pedal force performance at up to 0.7 g of deceleration - the equivalent of a very firm stop in traffic.
"We also do what we call the gorilla stomp test. We hit the brake pedal with 350 pounds of force, and there can be no permanent pedal deflection - no permanent damage to any of the parts," Kurcz said. "People rarely use the full braking power that's available. With the Five Hundred, you can really stand on the brakes with confidence, if you have to".