When you lift the hood of the 2021 Jeep Wrangler 4xe, it doesn’t look a lot different at first glance than one with a standard 2.0-liter turbocharged four-cylinder engine. In fact the engine itself is essentially the same.
The engine itself puts out 270 horsepower and 295 pound-feet of torque. You can see the turbocharger itself is mounted high on the driver side of the engine and features an electronically controlled wastegate. Intake air travels over the t op of the engine to an air-to-water intercooler on the passenger side before entering the combustion chambers.
Built around the gasoline engine is a 400-volt plug-in hybrid system comprised of two-electric motor generators, a large lithium ion battery pack – all putting power to all four-wheels through a traditional automatic transmission, full-time two-speed transfer case and solid front and rear axles.
It all starts with an engine-mounted water cooled belt driven motor generator unit with 44 horsepower that replaces the 12-volt alternator and starter. Its primary purpose is to start the engine and generate electricity. The only other belt driven accessory is the water pump. The AC compressor mounted to the engine is electrically powered.
Primary electric motive power comes from a powerful electric motor motor generator mounted in place of the traditional transmission torque converter that has 134 horsepower and 181 pound-feet of torque. Behind that is an eight-speed automatic transmission.
The engine is connected to the electric motor with a binary on/off clutch that allows it to shut off while the electric motor powers the vehicle or for the engine to idle and run on its own independently of the vehicle speed. Another variable clutch connects the electric motor to the transmission which allows for a more refined transition of power like a torque converter would provide.
All in, the gasoline engine and electric motor together can provide up to 375 horsepower and 470 pound-feet of torque. Battery power comes from a sizable 17-kilowatt-hour 96-cell lithium-ion battery pack located inside the passenger compartment under the rear seat.
Fully encased the battery pack has its own heating and cooling system to keep the battery at its best operating temperature. It has a built-in heater unit and cooling that uses the vehicle’s air-conditioning refrigerant.
A substantial combination power unit with battery charger, DC/DC converter, and a power inverter are packaged underneath the floorboard on the driver side in a substantial steel structure to keep it protected. And yes it’s all fully waterproofed to continue to give you 30-inch deep water fording capability.
You can plug-it in with a port located at the driver side fender, charging in about two hours on Level 2 (220-volt) power and about 12 hours on Level 1 (110-volt) household power. A full battery can power the Wrangler 4xe for 20-30 miles for electric-only operation, at which point it begins to operate as a traditional hybrid vehicle, motivating you with both gasoline and electric power.
Looking around under the hood, you can see that a 12-volt battery still exists to run accessories, the vehicle computer systems and lighting. It’s charged by the belt-driven motor generator. And when it comes to servicing the Wrangler 4xe, it’s not much different than traditional gas powered models.
The oil filler cap is located atop the engine at the front where you’d expect to find it. The oil check dipstick with its yellow handle is off the the passenger side of the engine. Replacing the oil filter is down below as usual.
The main fuse panel is located at the passenger side rear of the engine compartment behind the 12-volt battery and easily accessed. Just ahead of the battery is the reservoir for power steering fluid. Ahead of that is the air filter box where accessing the filter element itself does require the removal of a few bolts.
On the driver side you will find at the firewall the main engine coolant reservoir and to its right the brake fluid reservoir. Here you will note that Wrangler 4xe uses and electrically controlled brake system in lieu of a traditional booster and master cylinder.
Coming forward there are three caps to know. At the very front is the coolant reservoir for the turbocharger intercooler and power-electronics cooling circuit. Just behind that is the windshield washer fluid reservoir. Rearward of that is the coolant reservoir for the hybrid battery pack itself.