For 4x4 enthusiasts who see the electric-vehicle (EV) future as the conclusive death-blow to manual transmissions, there is hope. Jeep engineers have unveiled the first battery-electric Wrangler and it’s fitted with a 6-speed manual gearbox. The clever prototype powertrain is the centerpiece of the Wrangler Magneto concept vehicle, developed to show that the world’s original 4-wheel-drive utility vehicle can sustain the transition to zero-emissions propulsion without losing any off-road capability.
The Magneto’s goal is to prove it’s in fact got even more mojo in the dirt, mud and on slickrock than its combustion-engine cousins. Many in the trail-driving community believe that quiet electric drivelines will help keep off-roading alive, and even expand it, as emissions and noise regulations tighten.
The Magneto concept is based on a two-door 2020 Wrangler Rubicon. It uses a custom-built axial-flux electric machine that operates up to 6,000 rpm. The e-motor is connected to a six-speed manual transmission via a clutch that operates, according to Jeep, as it would with an IC engine. In quick-shift scenarios, when the clutch is engaged the electric machine engages regen to prevent rev-hang.
Axial-flux motor topology offers advantages in power density, efficiency, packaging – and potentially manufacturing – over conventional radial-flux machines. In axial-flux machines, the magnetic flux direction is parallel to the machine rotation, which is opposite to the flux direction in a radial machine. This gives the axial-flux machine a shorter and more direct flux path through the airgap. The shorter path enables a stronger magnetic field, resulting in greater efficiency and power density. And their shorter axial length helps reduce the length of the powertrain, according to experts.
Several companies are developing axial-flux e-motors with an eye to EV applications. Jeep did not reveal the source of the Magneto concept’s motor, nor did it provide details on the electric powertrain’s transmission. Production Wranglers use Aisin’s D478 6-speed manual transmission.
The Magneto’s 800-V power system consists of four lithium-ion battery packs with a combined capacity of 70 kWh. The batteries are distributed around the Wrangler to balance mass on the four wheels. One pack replaces the IC Wrangler’s midship fuel tank. Another is mounted opposite the fuel tank location. The third pack is located on top of the traction motor under the hood and the fourth pack mounts in the space normally taken up by the exhaust muffler. The vehicle’s DC-to-AC inverter is derived from racecar technology, according to Jeep.
The Magneto development team achieved power and torque outputs that essentially match those of Stellantis’s 3.6-L Pentastar gasoline V6: 285 hp and 273 lb-ft (212 kW and 370 Nm, respectively). The electric powertrain’s controls were calibrated to emulate the throttle tip-in and overall delivery of the V6. Claimed 0-60-mph (0-97 km/h) acceleration is 6.8 seconds.
The Magneto’s batteries, a vehicle interface box and battery control module are housed inside waterproof enclosures, to maintain Wrangler’s 30-inch (762-mm) fording capability. The packs also are protected by underbody skid plates. There are two 12-V batteries; one handles hotel loads, the other serves as an auxiliary power unit (APU) for accessories such as the electric winch. A DC-to-DC converter charges both 12-V batteries to support extended operation of the winch, lighting or other accessories. A 10-kw high-voltage heater keeps Magneto’s open-air tub comfortable for occupants.
“This is an interesting and cool idea that the hard-core Jeep enthusiasts will embrace,” observed Skip Nydam, a veteran transmission engineer who has worked at JATCO and GM Hydra-matic. “Combining a clutched manual gearbox with the battery and traction motor gives Wrangler drivers the ‘crawler’ effect they love and allows them to select gear ratios as they would with an IC engine.
“With this set-up, the driver truly has ratio control. I think the Magneto concept opens up many potential applications for EV drivers who want to shift gears themselves, including electric sports cars. I look forward to learning the details of how they engineered this.” More to come on this development.
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