Earlier this 12 months, Rivian expanded its plant in Regular, Illinois by almost 20% to fabricate its Enduro drive unit. It’s an about-face from the drive items provided by Bosch in Rivian’s Quad-Motor fashions, and may assist mitigate the bottlenecks to ramping manufacturing of the R1T journey pickup truck, R1S three-row SUV, and EDV electrical supply van. 

Outfitted within the EDV and Rivian’s new Twin-Motor fashions, the Enduro drive unit was designed and developed in home to be extra environment friendly, inexpensive, and higher insulated from provide chain shocks that quaked the business through the pandemic, proper as Rivian started manufacturing in 2021. 

Rivian purchased the forlorn Mitsubishi plant for $16.5 million in 2017 and now churns out each Quad Motor and Twin Motor fashions. A latest tour of the 4-million-square-foot facility showcased the 620,000-square-foot growth wanted to provide Enduro, and the way that drive unit will allow manufacturing for a inexpensive R2 platform, slated to be developed at a brand new plant in Georgia as early as 2026. 

For now, its Regular plant is on tempo to fabricate 52,000 Rivians this 12 months, with a goal of 150,000 items ultimately. Its passenger automobiles will probably be supplied with both the 4 motors developed by Bosch within the Quad Motor setup or the Normalized [ahem] Twin Motor setup. Because the starting of this 12 months, the EDV solely makes use of the Enduro single-motor drive unit on the entrance axle. 

Right here’s an summary of the Enduro drive unit and Rivian’s Twin-Motor fashions. 

Rivian plant in Regular, Illinois, manufacturing its Enduro drive unit

Rivian Twin-Motor availability

• Twin-Motor fashions offered with Customary, Massive, and forthcoming Max Pack battery sizes

• Efficiency Twin-Motor offered with Massive and Max Packs (accessible this fall)

• Customary Pack to be made with lithium iron phosphate cells, however has no launch date

• Each Quad-Motor up to now has been offered with the Massive Pack; no different pack measurement is obtainable

As of now, Rivian has solely offered the R1T and R1S as Quad-Motor fashions with the Massive Pack. Orders for the R1T Twin-Motor and Efficiency Twin-Motor with the Max Pack are open. The R1S Max Pack choice will probably be supplied on the configurator this fall. 

The Customary Pack holds probably the most promise when it comes to effectivity. With its LFP chemistry and the Enduro drive unit, the EDV was 35% extra environment friendly than earlier builds with the 135-kwh battery pack and the Bosch motor unit, in line with Rivian CEO RJ Scaringe. First deliveries of fashions with the Customary Pack are anticipated early in 2024.  

It stays to be seen how lengthy Rivian will maintain providing the dearer Quad-Motor setup.  

Rivian R1T and R1S Twin-Motor spec chart

Rivian Twin Motor pricing

• R1T Twin-Motor Customary Pack $74,800, together with $1,800 vacation spot

• R1T Twin-Motor Massive Pack provides $6,000 to $80,800

• R1T Twin-Motor Max Pack prices $16,000 extra to $90,800

• Efficiency Twin-Motor Massive Pack provides $5,000 to $85,800

• Efficiency Twin-Motor Max Pack prices $95,800

• R1T Quad-Motor Massive Pack prices $88,800

The Max Pack improve represents the most important soar in Rivian’s pricing construction, at $16,000. That makes each the Twin-Motor and Efficiency Twin-Motor dearer than the Quad Motor. 

The R1S three-row SUV is $5,000 extra throughout the board, however the Max Pack comes on-line within the configurator this fall.  

Rivian Enduro drive unit elements

Rivian Quad-Motor vs. Twin-Motor design 

• Enduro Twin-Motor drive items weigh about 220 kilos

• Quad-Motor rear drive unit weighs 320 kilos; Quad entrance weights 275 kilos 

• Enduro drive items are smaller, lighter, and extra environment friendly

The mechanical distinction between the Rivian Enduro drive unit and the Bosch unit comes all the way down to measurement, value, and effectivity. The Quad-Motor items home two motors and tow gear units in every unit, leading to bigger and longer casings. The rear-axle quad unit measures 135 mm lengthy, whereas the entrance measures 110 mm lengthy, in line with Mason Verbridge, Rivian’s principal drive unit engineer. With mounts and excessive voltage cables, the rear-axle quad unit weighs about 320 kilos, and about 275 kilos up entrance. 

Against this, every Enduro unit weighs about 220 kilos. For Twin-Motor fashions that provides as much as a weight financial savings of about 155 kilos. Each pound issues, even for an R1T Twin Motor Efficiency with a curb weight of about 6,750 kilos. 

“There are basic physics benefits of simply having one motor, one gearset, one mainly rotating meeting,” Verbridge defined. “With a Quad you’ve gotten two gear units, two motors, all of the bearings, all of the windage losses of double that rotating meeting.”

Rivian designed and housed the inverter, motor, and gearbox in a single casing, as an alternative of separate sealed entities that get bolted collectively. Primarily, there are fewer components to assemble, with much less weight and fewer redundancy.

“Primary philosophy is when you resolve necessities of all three subsystems then it makes all the pieces a lot simpler,” he defined. 

Rivian Enduro drive unit meeting

Rivian Enduro drive unit inverter elements

Rivian Enduro drive unit stator elements

Rivian Enduro rotor elements

The core advantage of creating its personal motors comes from the information of the way to program and optimize the motors from the beginning, as an alternative of setting a goal for what Rivian needed the motors to do from Bosch then adjusting it forwards and backwards to get it proper for the particular use case. 

For instance, the inverters changing DC from the battery to AC for the motor differ based mostly on the axle in Twin-Motor fashions. There’s a silicon carbide energy module for the entrance unit inverter however a less-expensive silicon energy module for the rear inverter. Silicon carbide has an effectivity of greater than 99% in comparison with about 98% effectivity with silicon, in line with Silva Hiti, Rivian senior director of electrical energy conversion. At peak effectivity, Hiti mentioned this interprets to three.5% extra vary than if Rivian used silicon energy modules for each inverters. It makes extra sense to make use of extra environment friendly (however dearer) silicon carbide on the entrance unit that’s used extra in Twin-Motor fashions. 

“By the point we got here to Enduro we understood these use instances tremendous effectively,” Verbridge mentioned. “If you already know precisely what the motor must do, you already know the place you possibly can actually dial in and prioritize being environment friendly in these areas on that working map.” 

Rivian plant in Regular, Illinois, manufacturing its Enduro drive unit

Rivian Quad-Motor vs. Twin-Motor drive modes

• Each Rivian passenger car has All-Function, Snow, All-Terrain, and Towing modes

• Efficiency Twin-Motor provides Sport mode

• Quad-Motor fashions add Preserve in addition to All-Terrain sub-modes, corresponding to Drift, Rally, Rock Crawl, Delicate Sand

In contrast to the Quad-Motor setup, the Rivian Twin-Motor doesn’t have a Preserve mode. As an alternative, the default All-Function mode decouples the rear axle to run as a front-wheel-drive truck for larger effectivity in most eventualities. However the rear axle powers on-demand as effectively, not simply with a button push. So if the driving force flooring it, the torque bias can shift from 100/0 to about 45/55 in a blink. 

All-Function within the Quad-Motor stays linked, except Preserve mode is chosen. So the default All-Function mode within the Twin serves an identical perform as Preserve within the Quad as probably the most environment friendly setting, limiting parasitic losses. Rivian wouldn’t say if all that torque on the entrance axle of the Efficiency Twin-Motor will chew by tires as excessively as Preserve mode does within the Quad, nevertheless it shouldn’t be as dramatic. 

The Enduro remaining drive ratio is decrease than the Quad, which is 12.9:1 in any respect 4 corners. The Twin-Motor has a remaining gear ratio of 11.04:1 within the entrance and 13.7:1 within the rear. Because it disconnects the rear axle and doesn’t have the additional surge of energy from Sport mode—in most driving eventualities besides when flooring it—there shouldn’t be as a lot uneven put on on the tires as there’s in Preserve mode within the Quad. 

Then there’s Sport mode within the Efficiency Twin-Motor. See extra under. 

Rivian plant in Regular, Illinois, manufacturing its Enduro drive unit

Rivian Twin-Motor efficiency

• R1T Twin-Motor makes 533 hp, 610 lb-ft of torque; it hits 60 mph in 4.5 seconds

• R1T Efficiency Twin-Motor makes 665 hp, 829 lb-ft; it hits 60 mph in 3.5 seconds

• R1T Quad-Motor makes 835 hp, 908 lb-ft; hits 60 mph in 3.0 seconds

In back-to-back testing on an oval loop of the R1T Efficiency Twin-Motor and the R1T Quad Motor, the Efficiency Twin-Motor had a slight lag earlier than the total energy got here on, however its surge to 60 mph in 3.5 seconds was nonetheless sufficient to drop my intestine. There’s loads of energy, particularly for a car this measurement and form. We didn’t get to check the usual Twin-Motor. Take into account the Efficiency Twin-Motor greater than a half step to the quad. 

In Sport mode, each drive items stay engaged. 

In a quick off-road demo, the Twin-Motor tackled the identical obstacles with the identical competency because the Quad Motor. The larger distinction in dealing with and four-wheel drive within the Quad as an alternative of all-wheel drive within the Twin comes from how torque will get routed to the wheels. The Twin depends on brake-based torque vectoring, whereas the Quad makes use of the 4 motors to apportion torque to every wheel. It’s a greater expertise in spirited on-road driving and extra daring off-road eventualities, however the Twin is so succesful that solely in back-to-back testing does it really feel a grade decrease. 

Rivian plant in Regular, Illinois, manufacturing its Enduro drive unit

Rivian Quad-Motor vs. Twin-Motor towing

• R1T tows as much as 11,000 kilos with both drive system

• R1S tows as much as 7,700 kilos with both drive system

• Anticipate a forty five% battery vary drop when towing, topic to many variables

Each drive methods tow the identical quantity: The R1T tows as much as 11,000 kilos; the R1S tows as much as 7,700 kilos. Towing comes commonplace with a 7-pin harness. It doesn’t have a load-distributing hitch, however Rivian says trailer sway mitigation is constructed into the software program. The brake controller prompts from the fitting steering wheel management or within the touchscreen.

We rode alongside in an R1T Efficiency Twin-Motor towing a 9,800-pound electrical supply van on a trailer. It was large, looming over us, as if a cinder block may very well be a predominant mast. The pull was noticeable, as was the wobble with some wind on an overpass. Energy was plentiful, braking by no means felt taxed, however the sheer measurement of the van on the trailer was obvious all through the demo. I can’t think about every other towing eventualities with that type of aero profile. 

Whereas in park, it may be adjusted to the low floor clearance setting of 10.1 inches for elevated effectivity on the freeway, or stay in the usual 11.3-inch setting. Drivers can even regulate the damping between Delicate and Stiff. 

Rivian estimates that placing it into Tow mode will decrease the estimated vary by 45%, however there are such a lot of variables at play that it’s a guesstimate based mostly on driving profile, trailer weight, and street circumstances, amongst different issues. One in all Rivian’s key benefits is how precisely it calculates estimated vary, and a pending towing replace anticipated within the subsequent two months ought to apply that accuracy to towing. It’s going to can help you enter the trailer weight or the system will calculate the trailer weight to create completely different trailer profiles, and the vary estimates will mirror that profile and/or weight and study over time to supply extra correct estimates. The replace will even issue in additional traction-based eventualities by enabling drivers to tow in Off-road and Snow mode in each Quad- and Twin-Motor fashions. The replace will even activate mattress digital camera angles for the R1T. 

For tow mirrors, look to the aftermarket. For many different issues, Rivian seems to have it coated. 

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Rivian supplied Inexperienced Automobile Reviews an evening of lodging and a manufacturing facility go to for an up-close have a look at the Enduro drive unit.