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Of all the “clean sheet” overhauls of the 43-year-old Chrysler minivans, this may be the most extreme. Nearly everything has changed; and it has Chrysler’s first retail plug-in hybrid system.
The platform is “all new,” though some sources claim it’s based on the CUSW setup used by the Jeep Cherokee. It is lighter by around 250 pounds than the prior van, despite the use of a true independent suspension at all four wheels and greater body stiffness.
The company claims its ride and handling are both better than its primary competitors. It was tuned and calibrated on rural roads, highways, and, of course, the Chelsea and Arizona proving grounds. There is much less body roll, and more agility, while the ride has been improved.
The upper body and frame were engineered as a single unit, to reduce weight while increasing stiffness. Enhanced chassis-to-body structure interfaces, such as suspension brackets and cradle attachments, are designed to ensure high stiffness at those points, thus abating low-frequency noise into the cabin while ensuring overall dynamic agility. Material was removed wherever it was found to be non-contributing to strength, through holes and scallops, by computer models.
The body has nearly 130 meters of adhesive, boosting stiffness, strength, and damping; the effect is expected to last for at least ten years. Also see sealing and noise reduction in the “cabin” page.
The company used advanced hot-stamped/high-strength steels, with 22% more high-strength steel than its predecessor (48% being advanced high-strength steel). The instrument panel beam is magnesium and the liftgate is magnesium and aluminum. Aluminum was combined with “thin-gauged, high-strength materials,” for chassis component tuning, quicker and more precise reactions, and better overall dynamic performance.
Chrysler spent 1.2 million CPU hours for fluid dynamics development and over four hundred hours in the wind tunnel to bring the 2017 Chrysler Pacifica out with a drag coefficient (cD) of 0.300, the top rating among its primary competitors.
The minivan includees a minivan-first active shutter system, cutting drag by an average of 10%; when closed, air is redirected around the van. The shutters are usually closed at high speeds but open at low speeds or if the coolant gets hot.
A steeper windshield angle channels air off the front portion of the upper canopy; aero-shaped mirrors were designed with the extra load of the closed shutters in mind. The rear angle was optimized to cut turbulence; sill claddings and aesthetic “blister” channel air away, particularly from the wheel openings. The roof taper channels air to the spoiler, whose trailing-edge design shapes the air wake.
The design of the rear pillars have an offset edge to push air off the rear upper corners of the minivan. A front-fascia close-out panel prevents air from channeling into the engine compartment and cuts “air swirl;” the engine shield pushes air down for the same reason. Front tire spats work like air dams, kicking air from the tires. Mid-floor belly pans on both sides, around 7 ½ feet long, are used on Touring and higher models; a rear suspension shield over the rear axle deflects air down, while a rear air diffuser panel channels air between the rear wheels. A hood seal cuts turbulence and noise. Even the wiper blades were optimized.
The MacPherson front suspension geometry was tuned for low camber loss, for more responsive steering and better cornering.
The front suspension cradle, attached via six points (most vehicles use four), is a third load path in frontal impacts. Its stiffness increases resonant frequencies to cut noise and vibration; its flat-bottomed geometry integrates with the belly pans to reduce air drag. Lower control arm attachments (hydraulic and rubber) dampen vibration and are designed for long-lasting brake judder performance.
The twin tube struts have high lateral stiffness; hollow strut rods with rebound springs increase side-to-side balance, while side-load coil springs contain transverse loads (high-strength springs allowed weight reduction). Isolators between the springs and their supports cut running noise; solid half-shafts cut weight and vibration.
This is the first independent rear suspension in a Chrysler minivan, not counting the Matra-SIMCA design that became the Renault Espace. It uses a twist blade design with a steel four-point steel cradle, and aluminum rear knuckles and shock mounts. The rear trailing arm packages, made of thin, high-strength steel, use dual bushings to decouple vertical rates from fore-aft compliance. The rear suspension cradle is a stamped, thin-gauge clamshell design with rubber isolators.
Most Pacifica minivan models have 17 inch wheels (including both hybrid models). Upper levels go to 18 inches, with a 20-inch option. Body improvements allowed the company to use low-rolling-resistance tires to increase efficiency.
The 2017 Chrysler Pacifica uses a new generation of electric dual-pinion power steering (EPS), cutting parasitic loss slightly, cutting noise, reducing maintenance and failure points, and providing increased tuning of feedback. The boost is altered based on steering torque, steering wheel speed and angle, and velocity; it is integrated with the stability control to compensate in split-traction, torque steer, and pull-drift (crowned road) situations.
The 2017 Chrysler minivan comes with four-wheel disc brakes and traction and stability control. The front has unusual vented rotors to prevent brake fade, while solid rear disks are quieter, more effective, and lighter, with better pedal feel. Brake booster, pedal ratio, and lining changes were made to enhance brake pedal feel, with less effort required at higher speeds. The rear calipers include an electric parking brake, cutting weight.
Four-channel anti-lock brakes monitor and control each wheel independently; the software has a steering wheel angle sensor to differentiate between straight-line braking and braking in a turn, cutting yaw during straight-line braking. Electronic brake-force distribution regulates front and rear braking pressure, regardless of load.
The traction control is also four-channel and operates at all speeds to cut wheel-spin. It normally acts by cutting torque from the engine, but it can also apply the brakes if needed.
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