|3.0L EcoDiesel. Click to enlarge.|
Among the many features of the new 2014 Jeep Grand Cherokee—introduced at the Detroit Auto Show—two in particular contribute to significantly improved fuel economy and driving performance: an optional new 3.0-liter EcoDiesel V-6 engine and a new eight-speed automatic transmission. That powertrain delivers 30 mpg (7.8 L/100km) highway for the SUV (4x2) and a range of more than 730 miles (1,175 km).
The new eight-speed transmission also is paired with Grand Cherokee’s 3.6-liter Pentastar V-6 engine—now achieving up to 25 mpg highway and more than 600-miles driving range—and its 5.7-liter V-8, now achieving up to 21 mpg highway.
|2014 Jeep Grand Cherokee. Click to enlarge.|
Producing 240 hp (179 kW) and 420 lb-ft (569 N·m ) of torque, the 3.0-liter EcoDiesel is capable of towing 7,400 pounds—more than any competitor’s gasoline V-8 equipped SUVs. With a 30% increase in fuel economy and a 56% increase in torque versus the Pentastar V-6 engine, the EcoDiesel achieves 21 mpg in the city and 30 mpg on the highway in 4x2 models. Full-time 4x4 models have fuel economy figures of 20 city and 28 highway.
The engine meets emissions standards for all 50 states. MultiJet II common-rail injection and Selective Catalyst Reduction (SCR) help this new engine achieve these results.
The 24-valve, dual-overhead-cam engine features a block and bed plate crafted from strong compacted graphite iron (CGI), which contributes to stiffness without penalizing performance.
The 3.0-liter EcoDiesel’s 60-degree cylinder banks enable more efficient packaging, while effectively balancing the potent inertia generated by torque-rich diesels.
A 1-4-2-5-3-6 firing order helps manage rotation so neatly it needs no balance shaft to deliver the required level of refinement. Further contributing to quieter performance, as well as optimal fuel economy and emissions reduction, is the clean diesel’s 2,000 bar common-rail fuel-injection system. Swirl-control intake ports benefit from a variable-geometry turbocharger and intercooler.
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 (EGR) for Tier II, Bin 5 and ULEV II compliance
- B5 biofuel compatibility
New 8-speed. The new eight-speed transmission features a wide ratio spread, high numerical first-gear ratio, quick shifting and aggressive torque-converter lockup.
Fully electronic, the eight-speed automatic features on-the-fly shift map changing, with manual shifting capability and Electronic Range Select using steering-wheel paddle controls. More than 40 individual shift maps for specific conditions optimize shift quality and shift points for fuel economy, performance and drivability. The intelligent software takes into account variables including engine torque gradients, kick-down events, longitudinal and lateral acceleration, grade changes, friction detection and downshift detection to determine the appropriate shift map. Additional parameters integrated into the control strategy include vehicle speed control, electronic stability control interaction and temperature.
The transmission efficiency and wide ratio spread improve fuel economy by operating at a lower engine rpm in both city and highway environments. The addition of more gear ratios also helps reduce the gaps normally associated with upshifting and downshifting.
Gear changes are nearly imperceptible due to the evenly spaced gear steps between each gear ratio. Internally, the transmission has four gear sets and five shift elements (multi-disc 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.
Eco Mode. The 2014 Jeep Grand Cherokee also features a new Eco Mode that contributes to its improved fuel economy. Eco Mode optimizes the Grand Cherokee transmission’s shift schedule and—in V-8 models—Fuel Saver Technology with cylinder deactivation as well as throttle sensitivity to maximize fuel economy. The Eco Mode also manages interactive deceleration fuel shut-off (IDFSO), which cuts fuel delivery when the vehicle is coasting to reduce fuel consumption.
In addition, the Eco Mode activates the vehicle’s air suspension system (if so equipped), lowering the Jeep Grand Cherokee to “Aero Ride Height” earlier to improve fuel economy.
Eco Mode is automatically engaged upon vehicle startup. A button on the center stack allows driver’s to disengage Eco Mode if more spirited performance is desired.