Chrysler powertrain technologies to highlight show floor at SAE 2013 World Congress

  • 06-Mar-2013 04:15 EST
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The ZF-designed eight-speed features a crawl ratio of 44.1:1 when paired with the available two-speed transfer case

As Host Company of the SAE 2013 World Congress, Chrysler will have a heavy presence in all aspects of the April 16-18 affair in Detroit. Its fingerprints already are all over the event, in fact. That’s to be expected of the Host Company, which begins to work with SAE International staff and the so-called Tier One Strategic Partner (for the 2013 event it is ZF) a year in advance to pull off the world’s largest annual dedicated gathering of automotive engineers.

The theme of the SAE 2013 World Congress, established with input from Chrysler, is “Achieving Efficiency.” A high expression of that theme is the automaker’s new MY2014 Jeep Grand Cherokee, powertrain features of which will be highlighted on the show floor.

Event leadership is being provided by SAE 2013 General Chair Mircea Gradu, Ph.D, a native of Romania and an SAE Fellow whose day job is Vice President Powertrain, Transmission & Driveline Engineering and Head of Virtual Analysis, Chrysler Group LLC.

“Concern for our planet triggers legislative mandates that significantly impact the automotive industry,” Dr. Gradu said last year in announcing the theme for SAE 2103. “We must persevere because ultimately, the path toward sustainability is the right path. To do that, we must leverage best practices and manage the creative tension from which innovation is born. SAE International and the SAE World Congress do just that. I am proud to serve as Chair for this important event, and Chrysler is proud to offer its support.”

A measure of Chrysler’s commitment to the SAE 2013 World Congress, in addition to Gradu’s premier role in it, is the scheduled appearance of Chrysler Group LLC Chairman and CEO Sergio Marchionne as the SAE World Congress Annual Banquet speaker on April 18.

Chrysler Group Technical Fellow Hussein Dourra will pick up SAE International’s prestigious Edward N. Cole Award for Automotive Engineering Innovation while joining more than 100 colleagues—led by Bob Lee, Vice President and Head of Engine, Powertrain and Electrified Propulsion Systems Engineering—as they participate in 85 technical sessions and presentations.

Chrysler powertrain and connectivity technologies will take center stage on the exhibit floor. Among the highlights will be its latest engine and transmission technology, including the Grand Cherokee’s eight-speed automatic transmission and 3.0-L EcoDiesel V6 engine.

The new-for-2014 transmission is standard equipment on the Grand Cherokee. The eight-speed features a crawl ratio of 44.1:1 when paired with the available two-speed transfer case—a 46% improvement over the previous model—as well as on-the-fly shift-map changing, manual shifting capability, and paddle-activated Electronic Range Select. More than 40 individual shift maps for specific conditions optimize shift quality and shift points for improved fuel economy and enhanced driveability.

The intelligent software takes into account variables such as kick-downs, engine torque gradients, longitudinal and lateral acceleration, grade changes, and friction detection. Also integrated in its control strategy are temperature, vehicle speed-control, and electronic stability control interaction. The transmission’s 7.03 ratio spread affords operation at low rpm in city and highway environments to deliver optimum fuel economy. It also makes for smoother shifting.

Internally, the transmission has four gear sets and five shift elements (multidisc clutches and brakes). Only two shift elements are open at any time. With fewer open shift elements, drag losses due to multiple parts rotating relative to one another are reduced, improving fuel efficiency.

Further enhancing the Jeep Grand Cherokee’s capability is its new 240-hp (179-kW) 3.0-L EcoDiesel V6. Generating peak torque of 420 lb·ft (569 N·m), it gives the SUV a 7400-lb tow rating.

Arguably, the diesel-powered Jeep Grand Cherokee’s most noteworthy metric is the 4 x 2 model’s anticipated highway fuel-economy rating of 30 mpg. This allows for a best-in-class driving range of more than 730 mi (1175 km). Full-time 4 x 4 models deliver an estimated 21 mpg city and 28 mpg highway.

The new 50-state-legal 3.0-L EcoDiesel engine burns clean because of MultiJet II common-rail injection and selective catalyst reduction. The 24-valve, dual-overhead-cam V-6 features a block and bed plate crafted from strong compacted graphite iron, which contributes to stiffness without penalizing performance. The 60° cylinder banks enable more efficient packaging, while effectively balancing the potent inertia generated by torque-rich diesels.

The new engine’s 1-4-2-5-3-6 firing order helps manage rotation so neatly it needs no balance shaft to deliver impressive refinement.

Further contributing to quieter performance, as well as optimal fuel economy and emissions reduction, is the clean diesel’s common-rail fuel-injection system. Its 29-ksi (2000-bar) pressure is unmatched by any solenoid-based system, according to Chrysler.

Swirl-control intake ports benefit from a variable-geometry turbocharger and intercooler that ensure the required engine response, whether merging on-road or surging off-road. Temperature extremes are also addressed: the new engine’s turbo is water-cooled to handle searing heat, while low-voltage ceramic glow plugs accommodate quicker cold-weather starts.

Other key features and benefits include:

• Finger-follower actuated valves with hydraulic adjusters

• Chain-driven camshafts

• Piston-cooling oil jets

• Water-cooled exhaust-gas recirculation for Tier II, Bin 5 and ULEV II compliance

• B5 biofuel compatibility

The new diesel enhances a Grand Cherokee powertrain lineup that already includes a pair of celebrated gasoline-powered engines, the 3.6-liter Pentastar V6 and the 5.7-L Hemi V8. The latter benefits in model-year 2013 from Eco Mode, which optimizes the transmission’s shift schedule. Other Eco Mode features are cylinder-deactivation technology and deceleration fuel shut-off. In addition, Eco Mode enables earlier activation of the vehicle’s air suspension system (if so equipped), lowering the Jeep Grand Cherokee to “Aero Ride Height” to improve fuel economy.

The Hemi produces 360 hp (268 kW) and 390 lb·ft (529 N·m) and boasts a best-in-class towing capacity of 7400 lb.

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