“We're losing our deflector shield! Go strap yourself in, I'm going to make the jump to light speed,” said Han Solo in Star Wars. The auto industry is also making a “jump," not to light speed but from internal combustion engines (ICE) to all electric vehicles. The Motor Age article, “The Future of Hybrid Vehicles” (January 2019), concluded that the transition from ICE to battery power will take place over time via powertrains that use both ICE and electric motors — hybrids. Most OEMs offer one or more hybrid models but only for cars or crossover vehicles. The full-sized pickup truck market has been without this technology until now.
The 2019 Dodge RAM 1500 series trucks are leading the charge with the first, full-sized pickup truck hybrid offerings. The 2019 RAM 1500 eTorque is not a full-fledged hybrid system but is a “mild hybrid,” a term that means the on-board electric motor can’t power the vehicle on its own without the help of the gasoline engine. Many people that have test driven a RAM 1500 with the eTorque system conclude that it feels like a smooth, unobtrusive engine stop-start system that shuts off the V-6 or V-8 engine when waiting at traffic lights, but eTorque is more.
eTorque overview
The concept of the eTorque system is simple. eTorque replaces the conventional alternator with a more powerful motor/generator connected to the engine via a large serpentine belt. Depending on operating mode, it can produce electrical power for charging the 48-volt battery or provide electrical power-assist to the engine.
The eTorque stop-start operation is seamless. At a stop and as the engine shuts off, the motor/generator delivers torque to the engine to actively dampen vibration by countering the rotating mass and pulses of the cylinders’ compression cycles. When the driver lifts their foot off the brake and on to the accelerator pedal, the system pushes torque to the engine on a pulsating basis that matches the compression cycles to smooth engine start. After a stop, if the driver is very quick off the brake and back on the gas, the eTorque motor/generator provides a significant push during the first half-rotation of the wheels as the engine is restarting. Because the torque curve of the gasoline engine is so steep, it overruns the torque of the motor/generator quickly and the transition from electric power to gas is not noticeable. On V-8 applications that use Ram’s Multi-Displacement System (cylinder deactivation), eTorque smooths engine transition from eight to four-cylinder modes in much the same way as during stop/start operation.
When the engine is operating near its horsepower or torque peak, the eTorque system does not provide additional power. As mentioned before, it does provide power to initially start the vehicle moving — 12 horsepower for the V-6 and 16 for the V-8. Torque output of 39 lb/ft for the V-6 is multiplied by the belt drive to create a 90 lb/ft assist and the V-8 version creates 49 lb/ft, again multiplied by the belt for an assist of 130 lb/ft. Because the electric motor is rotating three times for every revolution of the engine, by the time the engine reaches peak power the electric motor’s output is negligible and thus only adds power at low engine rpm.
Using eTorque’s electric motor, transmission upshifts are smoothed by reducing engine rpm to match the next gear during an upshift. This reduces wear on the transmission clutches that normally accomplish this task. When decelerating the eTorque motor can “blip” the engine to match engine revs to smooth downshifts. Transmission assist is possible because the system can switch from full output to full regeneration in 60 milliseconds with the drive belt being the limitation to faster transitions.
eTorque battery and charging
The motor/generator charges the 48-volt battery using the truck’s deceleration momentum each time the driver lifts off the accelerator or applies the brakes, a function hybrid techs know as "regen" or regeneration. The system also charges a conventional 12-volt battery and powers all accessories more efficiently than a standard alternator. To save fuel during cruise mode, the system provides power for electrical loads via the 48-volt battery instead of loading the generator and 12-volt battery. For cold engine starting, the 12-volt lead-acid battery and conventional starter motor starts the engine.
It would appear that these pickup truck owners can’t stand that other vehicle owners would drive a car, let alone one powered by electricity. They seem to particularly target Tesla charging stations but presumably hate all hybrid and electrical vehicles equally. Chrysler’s offering of their eTorque technology on the popular RAM series trucks may in some way demonstrate to pickup truck owners that electricity is good, not evil, and truck hybrids (and even all-electric powered trucks) are the future. When the price of an all-electric Ford F-150 (or another brand/model) is the same as a diesel or gas-powered truck, when there is an infrastructure of charging stations to match traditional filling stations and it costs half as much to travel the same miles, OEMs will sell more electric vehicles than gas or diesel eventually eliminating them altogether—it’s only a matter of time.
The 48-volt battery pack uses 12 pouch-style battery cells of nickel manganese cobalt lithium-ion made by LG Chem (manufactured in its Holland, Michigan factory). The same company also supplies batteries for the Chevy Bolt EV, Volt and other hybrids. The 30-pound, briefcase-sized, 430-watt/hour battery pack mounts against the rear wall of the cab behind the rear seats in a dead space so rear seat functionality and cargo space are not affected. The battery pack includes a DC-to-DC converter to transform 48 to 12 volts for electrical loads and to charge the starting battery. The eTorque systems only use 130 watt/hours of capacity to ensure that the battery pack lasts the life of the truck.
When the brakes are lightly applied, initial deceleration is provided by the motor/generator loading as it recovers energy and charges the 48-volt battery. In this mode the conventional disc brakes are disabled. For heavier brake applications, a blend of disc brakes and regenerative braking is used. During hard braking, the regen function is disabled and only the disc brakes are used for stopping.
eTorque engine options
The eTorque system for the two engines offered on the RAM 1500 series is similar but different. The V-6 uses a liquid-cooled eTorque motor from Continental that is mounted in reverse on the front of the engine adding length. The 5.7L Hemi uses an air-cooled electric motor supplied by Magneti Marelli mounted on the top of the engine adding height. The V-6 version adds 90 pounds to the overall weight of the truck and the V-8 application adds 105 pounds. eTorque comes standard on RAM 1500s with the 3.6L Pentastar V-6 and is available as a $1,450 option on the 5.7L Hemi V-8. Maintenance for the eTorque system only requires periodic visual inspection of the components and replacement of the serpentine belt at 150,000 miles.
Fuel economy
Why purchase a RAM 1500 with the eTorque system? There is no badge on the tailgate indicating that the eTorque system is present. Fiat Chrysler Automobiles has probably made a conscious choice to not advertise the RAM 1500 series pickup trucks as an environmental-friendly vehicle because their target market may not be quite ready to join other hybrid vehicle owners in trying to save the earth. The bottom line justification for eTorque has to be fuel economy. According to Chrysler, the system boosts fuel efficiency by 10 to 12 percent in real-world driving with EPA fuel economy figures of up to 20 mpg city, 26 highway, and 23 mpg combined on V-6 models. The Hemi eTorque gets 19 mpg combined city and highway driving, a two-mpg increase over V-8s without eTorque. On the V-8, a single 90-second stop/start event saves 1.7 ounces of gasoline. Multiply that times 10 stoplights every day for a year and that’s almost 50 gallons of fuel saved. Because of the system’s design, owners that drive in stop-and-go city environments will benefit most from eTorque’s fuel efficiency.
Future of hybrid trucks
What’s the future of hybrid trucks? All automakers would like to raise their combined mpg for every vehicle they produce so it is very likely that there will be a future for full-sized hybrid trucks. Ram’s three quarter ton and one ton pickups and vans are the next logical vehicles for some type of hybrid system. Full or partial electrification makes sense on large work trucks because electric motors excel in providing high torque effort from idle that is ideal for hauling heavy loads and towing. With Ford’s plan of bringing an F-150 hybrid to the market in 2020, and even an all-electric truck on the drawing board for a possible 2021 launch, can Chrysler, Chevy, Toyota, etc. sit by and watch to see if these models sell? Most likely not, and the race to offer hybrids and then all electrical trucks and other vehicles is definitely on.
