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発行日時
2018/1/15 18:02
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2019 Ram drops weight, gains 48V eTorque mild hybrid system
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http://www.greencarcongress.com/2018/01/20180115-ram.html 2019 Ram drops weight, gains 48V eTorque mild hybrid systemへの外部リンク
記事詳細
15 January 2018
FCA pulled the wraps off the new 2019 Ram 1500 at the Detroit Auto Show. Overall weight for the Ram 1500 has been reduced by 225 pounds (102 kg). As the truck’s backbone, the frame uses advanced materials and engineering to eliminate 100 pounds while increasing stiffness and durability for 12,750 pounds of towing capability and 2,300 pounds of payload.
An all-new 48V eTorque mild-hybrid system delivers improved fuel efficiency for both 3.6-liter Pentastar V-6 upgrade and 5.7-liter HEMI V-8 configurations. The eTorque mild hybrid system is one of several changes made to the powertrains for the 2019 Ram 1500. The changes include upgraded TorqueFlite eight-speed automatic transmissions, strategic weight reductions and innovations, such as quickly heating lubricants to minimize viscosity-related efficiency losses.

RAM 1500 with eTorque.
eTorque. The eTorque mild hybrid system replaces the traditional alternator on the engine with a belt-driven motor generator unit that performs several functions. The motor generator unit works with a 48-volt battery pack to enable quick and seamless start/stop function, short-duration torque addition to the engine crankshaft in certain driving situations and brake energy regeneration, which improves responsiveness and efficiency.
With the engine running, eTorque’s motor generator unit feeds 48-volt current to a 330 watt-hour lithium-ion Nickel Manganese Cobalt (NMC)-Graphite battery. The battery pack includes a 3-kilowatt DC-to-DC inverter to maintain the battery’s state of charge and convert 48 volts to 12 volts to power the Ram 1500’s accessories and charge its conventional 12-volt lead-acid battery.

3.6L Pentastar with eTorque.
The small-suitcase-sized, air-cooled battery pack mounts to the rear wall inside the Ram 1500’s cabin. The case is insulated to dampen noise from the dual cooling fans. Cooling air is drawn from inside the truck and vented via the built-in cabin exhausters.
The V-6 and V-8 engines with eTorque retain a conventional 12-volt starter motor, used for cold starts and first start of the day due to its greater efficiency in extreme temperatures.
In addition to spinning the engine for restarts, the eTorque also recaptures energy during deceleration and braking to feed charge to the battery pack. eTorque also enhances the driving experience of the 2019 Ram 1500 by adding torque to the crankshaft during gear changes to minimize noise, vibration and harshness (NVH).
The eTorque motor generator is slightly different between the 3.6-liter Pentastar V-6 and 5.7-liter HEMI V-8 applications. The Pentastar eTorque unit is liquid cooled and mounted on the front of the engine. The HEMI V-8 eTorque unit is air cooled and mounted toward the top of the engine in the traditional alternator location.

5.7L HEMI with eTorque.
Both eTorque motor generator units employ a pair of belt tensioners to keep the 8-rib drive belt tight when the unit is generating electricity or adding torque to the crankshaft.
The 5.7-liter HEMI V-8 will also be available without the eTorque system.
3.6-liter Pentastar V-6. The all-aluminum Pentastar V-6’s versatility, with significant horsepower and torque production throughout the rpm range, makes it a workhorse engine throughout the FCA US vehicle lineup and the ideal base engine for the 2019 Ram 1500.
The upgraded version of the Pentastar V-6 is the standard engine in most trim levels of the 2019 Ram 1500, specifically tuned for truck duty and rated at 305 horsepower and 269 lb-ft of torque.
The newest Pentastar V-6’s advanced technologies, such as wide-range variable valve timing and two-step variable valve lift, deliver an optimized blend of power and fuel economy, based on the driver’s demand. A cooled exhaust gas recirculation (EGR) system enables improved fuel economy and emissions performance at higher loads.
The compact, 60-degree, all-aluminum block is constructed of high strength die-cast T380 aluminum with cast iron bore liners. Six bolt main bearing caps contribute to an extremely rigid lower engine structure. Cast aluminum pistons, treated with a friction-reducing coating and piston rings, drive forged connecting rods. Aluminum cylinder heads carry dual overhead cam shafts, four valves per cylinder and utilize high-tumble intake ports. The exhaust manifolds are cast integral with the cylinder heads.
The Pentastar V-6 uses an 11.3:1 compression ratio but runs on regular 87-octane fuel to reduce the cost of ownership.
The two-step variable-valve lift (VVL) system remains in low-lift mode in most driving situations. When the driver demands more power, VVL switches to high-lift mode for improved performance.
The variable valve timing (VVT) system, with dual-independent cam phasing and 70 degrees of authority, helps reduce pumping losses in the engine.
In the 2019 Ram 1500, the 3.6-liter Pentastar V-6 engine is available in most configurations, including the four-wheel-drive powertrain and Crew Cab models.
5.7-liter HEMI. The 5.7-liter HEMI V-8 delivers 395 horsepower and 410 lb-ft of torque with performance-enhancing and fuel-saving technologies that include variable-valve timing and Fuel Saver Technology (cylinder deactivation).
With Fuel Saver Technology, the engine control computer turns off fuel and spark, and closes the valves to four of the engine’s eight cylinders during light load operation, such as highway cruising when full power is not needed.
For the 2019 Ram 1500, FCA engineers broadened the operating zone of the Fuel Saver Technology via the addition of a pair of active vibration dampers, mounted on the frame, and Active Noise Cancellation technology in the truck cabin. The expanded range of operation yields an additional 0.5 miles per gallon (mpg) on the highway. Transparent to the driver, the system operates between 1,000 and 3,000 rpm while continuing to enable V-8 power for acceleration and heavy loads.
Variable valve timing helps maximize fuel economy by reducing the engine’s pumping work via a delayed closing of the intake valve, which increases the expansion process of the combustion event.
Another change for the HEMI V-8 in the 2019 Ram 1500 is the switch to an electric cooling fan, replacing the previous 400-watt electric/mechanical fan hybrid setup. Precisely controlled by the engine control computer, the new 850-watt electric fan, mounted to the radiator, uses Pulse Width Modulation to tailor the fan’s energy draw to the cooling demand. Eliminating the traditional fan blade mounted to the front of the engine helps improve fuel economy by reducing parasitic losses and fan noise.
The 2019 Ram 1500 meets ULEV70 emissions regulations via revised computerized powertrain controls and upgraded emissions hardware.
iDFSO. The V-6 and V-8 powertrains in the 2019 Ram 1500 also reduce fuel consumption with an Interactive Deceleration Fuel Shut Off (iDFSO) feature that pauses fuel flow to the engine cylinders when the vehicle is decelerating. For the 2019 model year, the iDFSO feature is improved to be active in third gear and higher.
TorqueFlite eight-speed automatic transmissions. Every 2019 Ram 1500 is equipped with a fully electronic TorqueFlite eight-speed automatic transmission with a wide spread of gear ratios that keeps engine rpm in the right range for the task.
Trucks equipped with the 3.6-liter Pentastar V-6 use an FCA-produced TorqueFlite 850RE transmission. The 2019 Ram 1500 with the 5.7-liter HEMI V-8 uses an upgraded TorqueFlite 8HP75 transmission. Both TorqueFlite transmissions use a new generation of computer controllers that process data faster and coordinate transmission operation with the eTorque mild hybrid system. The transmissions employ on-the-fly shift map changing, enabling them to respond quickly to changes in driver demand.
There are more than 40 individual shift maps, to optimize shift changes and points for fuel economy, performance and drivability. Shift strategy takes into account a number of variables, including:
Engine torque changes
Gear downshifts
Longitudinal and lateral acceleration
Hill detection
Vehicle speed control
Electronic stability control interaction
Temperature
The transmissions use shift-by-wire technology, eliminating a mechanical linkage between the transmission and the gear selector. The 2019 Ram 1500 retains an innovative rotary e-shift dial mounted on the left side of the instrument panel’s center stack, thereby freeing up space traditionally occupied by a console- or column-mounted shift lever.
The TorqueFlite 850RE and 8HP75 transmissions use identical gear ratios. Sixth gear is a direct drive, while gears 7 and 8 have overdrive ratios. The wide gear ratio spread helps maximize fuel economy by helping lower engine rpm in city and highway driving. Internally, both transmissions have 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.
2019 Ram 1500s equipped with eTorque technology feature a hydraulic pressure accumulator, for instant response following a stop/start event.
Thermal management. Today’s Ram 1500 employs a thermal management system that taps into heated engine coolant to speed up the warmup of automatic transmission fluid and engine oil to maximize the fuel saving benefits of those fluids.
The 2019 Ram 1500 takes that strategy a step further with an industry-first patented application that uses heated engine coolant to warm up the rear axle lubricant of 4x2 trucks.
The engine control unit manages a three-way valve in the engine cooling circuit. Heating the truck cabin always takes priority, based on the HVAC temperature setting. Once heated, the valve routes coolant to the rear axle, where it circulates through a cavity in the double-layer axle cover to warm the gear oil. The warmed gear oil is less viscous and brings the axle to peak operating efficiency faster. Also, the system helps prevent the rear axle from exceeding maximum temperatures during demanding conditions such as hauling and trailer towing.
The 2019 Ram 1500 continues to use the thermal management system to bring the transmission fluid and engine oil to operating temperature quickly. The system also serves a cooling function under high load/high ambient temperature conditions to ensure the transmission fluid temperature is controlled.

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