Despite the popularity of SUVs and CUVs, nothing beats a minivan for its combination of interior flexibility, ingress/egress, passenger comfort, cargo hauling and, in some cases, fuel efficiency. While the segment isn’t as large it was in 2000, when sales peaked at 1.37 million deliveries in North America, about 500,000 minivans are still are sold annually—ample profit-spinning volume that analysts expect will be sustained through at least 2020.
As millions of customers would likely attest, the minivan is “still the best transportation ‘tool’ for families,” observed Tim Kuniskis, head of FCA’s passenger car brands, when he pulled the cover off Chrysler’s 2017 Pacifica – the company’s sixth generation minivan. It was shown to Automotive Engineering and other media on embargo prior to the car's official debut January 11 at the 2016 North American International Auto Show.
Underpinned by what Chief Engineer Jessica LaFond called “an-new platform designed for this role” (FCA’s global E-segment front-drive architecture), the Pacifica was developed with a focus on best-in-class ride, handling, and NVH attenuation—the latter achieved through great attention to vehicle aerodynamics. There are 37 new features LaFond and Kuniskis described as “innovations.” They include the segment’s first plug-in hybrid powertrain with FCA-developed electrified transmission offering up to 80 mpg equivalent (MPGe) fuel efficiency, hands-free sliding doors, standard active noise cancellation for the cabin, a 360° birds-eye-view camera, and a cleverly reconfigured and easier to use Stow ‘n Go storage system that required a dedicated floorpan.
There's an optional and removable eighth-passenger seat in the second row that weighs 37 lb (16.8 kg), and a comprehensive electronic features suite that puts Pacifica into the segment’s safety, HMI (with new Uconnect Theater and 8.4-in touchscreen display), and connected-car vanguard.
The overall design injects a “CUV-like character” into the two-box theme that Chrysler has refined continuously since 1984, noted Ralph Gilles, FCA’s global design chief. The segment’s longest wheelbase (121.6 in/3089 mm) enables a “living room on wheels” interior package with seating for eight as described by LaFond. Overall length is 203.6 in (5172 mm)
Mixed-metals mass reduction
The Pacifica’s claimed coefficient of drag (Cd) is .300, which engineers claim is best in class. It is the result of 400 h of scale-model and full-size work in FCA’s wind tunnel, along with a claimed 1.2 million CPU hours for CFD development. CdA is 9.95. Active grill shutters are a segment first and help reduce drag on average by 10% at highway speeds.
The body is also strong and mass efficient. LaFond’s development team in Auburn Hills, MI, achieved a 30% gain in body torsional stiffness while reducing total vehicle mass by about 250 lb (113 kg), compared with the outgoing model (RT program) that debuted in 2008.
“We really optimized the new high-strength and advanced hot-stamped high-strength steels,” she said, with about 22% more HSS in the 2017 vehicle than its predecessor. Use of structural adhesives to replace mechanical fasteners and welds was increased on the program. LaFond also noted the team’s “extensive” FEA work to create an engine box that optimizes packaging, strength and predictable deformation, to meet the IIHS’s 25% narrow offset crash test.
With the additional feature content that was certain to increase Pacifica’s curb weight over the previous-gen vehicle, mass reduction was a “big detail focus” within the development program, she explained. There’s a magnesium cross-car beam, and Pacifica’s exterior panels include the first aluminum sliding doors on a Chrysler minivan. The rear liftgate uses a magnesium inner and aluminum outer panel.
The hydroformed front suspension cradle is solid mounted at six points, and features octagonal side rails in thin-wall HSS, with lightening holes strategically placed. The front MacPherson strut suspension is aluminum intensive, with forged lower control arms, cast knuckles, and an extruded aluminum cross member for the electric steering gear. Aluminum also is key to reduced mass in the engine brackets and rear upper shock mounts.
Also, the use of rebound springs inside the rear shocks enabled the rear stabilizer bar to be eliminated. The chassis team is proud of a new rear trailing-arm design, rendered in thin-gauge steel to save mass.
The independent rear suspension module mounts on an isolated, full-perimeter type steel cradle, also using lightening holes to save weight.
Pacifica’s segment-longest wheelbase, combined with ample vehicle width (79.6 in/ 2022 mm) and wide front/rear track—68.3-in/1735-mm for non-hybrid models and 68.2-in 1734-mm for hybrids—creates a 200 ft3 (5.66 m3) interior volume, which LaFond claims is best in class and also has segment-leading front legroom, she said.
NVH countermeasures are designed to address root causes and noise paths, LaFond explained. Air leakage into the passenger compartment is attenuated to around 225 CFM. The 5.0-mm acoustic laminate windshield glass delivers a claimed 2.5 to 3.0 dB improvement over standard tempered glass. All doors feature triple sealing, and the wheelhouse liners are specially designed to muffle road noise. Engineers said wind noise in the Pacifica is as low as 63 dB at 70 mph. The vehicle’s Articulation Index (speech intelligibility; 0%=worst, 100%=best) is above 84% at 70 mph.
Pacifica also features a standard active noise cancellation system that uses the audio system and four strategically located microphones to introduce opposite-wave sound to the cabin as an offset to unwanted sounds. Engineers said the system also enables more fuel-efficient engine calibrations due to the reduced need for NVH-related tradeoffs, and reduces the need for acoustic-damping material that adds unwanted weight.
Segment-first hybrid drive system
Pacifica’s power comes from both conventional and Atkinson-cycle (for the hybrid model) versions of FCA’s newly invigorated 3.6-L Pentastar V6 (see http://articles.sae.org/14322/). A stop-start system will be added later in the 2017 model year. The conventional non-hybrid version is coupled with the ZF-Chrysler 9-speed planetary automatic.
In 3Q16 the Pacifica Hybrid debuts as the industry’s first electrified minivan. With an estimated 248 hp (185 kW) produced by its Atkinson-cycle, 12.5:1 compression V6, the vehicle will deliver an estimated EV-only range of 30 mi (48.2 km).
Centerpiece of the new hybrid driveline is FCA’s in-house designed electrically-variable transmission (EVT). The unit, long in development (and of which more will be described in a future article), uses two electric machines, both of which are capable of driving the vehicle’s wheels thanks to a one-way clutch. The 16-kW·h lithium-ion battery is packaged under the second-row seats.
The vehicle has provision for SAE Level 1 and 2 (via combo connector) charging.Continue reading »