Jaguar’s New EV Pacesetter

July 1, 2018

Dan Carney

The state of the art of battery electric vehicles is progressing so quickly that each new vehicle introduction advances it. That is exactly what Jaguar has done with the I-Pace crossover SUV.

The technical specifications for the British beauty—built at Magna-Steyr’s Graz, Austria, complex—are similar to those of Tesla’s Model S and Model X P90D. Both companies build EVs with dual front and rear motors powering all four wheels and with 90 kW·h lithium-ion battery packs capable of delivering 240 miles (386 km) of driving range.

Where the new Jag outpaces Tesla’s current S and X, however, is in its dynamic qualities—not surprising, considering Jaguar’s history as a sports car company. The I-Pace’s superior ride and handling are enabled by its adaptive suspension system, which offers a variety of settings to suit various conditions.

But the I-Pace’s unexpectedly accurate steering and neutral handling characteristics during spirited driving (experienced by Automotive Engineering both on the track and on winding mountain roads during the car’s media launch) are made even more noteworthy by its placid ride during normal highway driving.

The keys to agility

Manufacturers have claimed “car-like” handling from their crossover SUVs for a while, but it is only the most recent examples, such as the BMW X4 M40i and the I-Pace, which truly deliver twisty-road handling on par with sport sedans.

Jaguar engineers employed continuously-variable shock absorbers that provide clearly discernible differences in ride and handling depending on the setting, as the shock adjust for the road surface and driver inputs. The vehicle’s lack of body roll, pitch and dive during such driving is an impressive accomplishment.

Standard air springs capable of raising the body 2 inches (50.8 mm) are employed to give I-Pace a modicum of “off road” capability, as well as to benefit ingress and egress. And at road speeds above 65 mph (105 kph), the system automatically lowers the car 0.6 inches to optimize aerodynamics.

Another factor enabling I-Pace to deliver on the driver’s requests is the electric brake booster— necessary due to the absence of any engine vacuum to power a conventional vacuum booster. Jaguar engineers explain the e-booster lends greater flexibility when blending mechanical braking with electric regenerative braking.

The I-Pace’s electric regenerative braking can slow the car at 0.4 g, simply by lifting off the accelerator pedal. The combination of this forceful brake force and the equally authoritative acceleration available by pressing down on the pedal make the I-Pace easy and smooth to bend through mountain switchbacks.

The potential of these systems is made possible by the I-Pace’s all-aluminum chassis, which is the most rigid Jaguar has ever produced, according to senior program manager Simon Patel. The structure registers 36,000 newtons per degree of deflection, he noted.

The extra stiffness in comparison to Jaguar’s other aluminum-intensive models is courtesy of the extremely stiff battery pack installed in the I-Pace’s floor, he said. Without it, the I-Pace would be comparable to other Jaguar models in terms of chassis rigidity, Patel said.

Inside the battery box residing beneath the I-Pace’s floor are 36 separate modules containing 12 prismatic-type cells each. The 388-V pack weighs 1,329 lb (603 kg), but because it’s mounted low in the chassis the car never feels heavy despite its 4,468-lb (2026-kg) curb weight.

This despite the I-Pace’s standard panoramic skylight, whose large glass panel provides abundant cabin light at the cost of some significant weight mounted at the very top of the car.

Electrifying details

I-Pace’s SAE combo-connector CCS port offers 100-kW·h DC fast charging—engineers claim an 80% charge in 40 minutes. A more typical 32-A, 230-V (7 kW) home charger will need 10 hours for the same job. Drivers can program charging times through the in-dash touchscreen display or by using the Jaguar InControl Remote app on their smartphone.

The prismatic-cell form factor and the modules’ construction permit maximum energy density for the smallest possible battery pack, with optimum thermal management, Patel said. Cooling passages beneath the pack circulate conventional ethylene glycol/water coolant to keep temperatures in the cells’ operating range.

The limiting factor in hard driving is cooling of the front and rear electric motors. “Very long duration [performance driving] gets into the motors’ limits,” Patel explained. If either of the motors tops 160 ̊C, then the propulsion system control reverts to a lower-performance “protection” mode.

However, without specifying, Patel said the I-Pace can run at its 124-mph (199 kph) top speed for “a long time.” That is in contrast to Tesla’s vehicles, which deliver astounding acceleration runs but suffer rapid heat-related power depletion during continuous track testing.

In our test drive opportunity, the I-Pace demonstrated tolerance for 50 miles (80 km) of hard mountain road driving and for three consecutive laps at maximum speed on Portugal’s Algarve International Circuit. Jaguar engineers and test drivers insisted that they’d driven the cars for much longer durations on the track with no reduction in performance.

The permanent-magnet AC synchronous motors each produce 197 hp (147 kW) and 256 lb·ft (347 N·m), for a combined peak of 394 hp and 512 lb·ft (294 kW and 694 N·m, respectively). Jag’s nomenclature for this spec is EV400, and the motors drive the front and rear wheels independently through single-speed transmissions.

The system is programmed to favor the rear motor during light throttle application at speeds of less than 30 mph (48 kph). Above that speed the power split tends to be 50/50, to avoid overloading either motor, Patel said.

Zero-60 mph acceleration takes 4.5 seconds. There are no over-boosted “Insane” or “Ludicrous” modes for short bursts of high power, he continued. “We want it to drive like a fully normal Jaguar car,” he explained.

Gadget central

Drivers who are more entranced by their smart phones than by these traditional benchmarks of automotive performance might be more excited by other features, such as the Jaguar InControl Touch Pro Duo infotainment system, which includes a 10-inch main display in the center of the dashboard and a 5.5-inch lower display to handle common functions.

And Jaguar’s Amazon Alexa Skill lets drivers access information in the InControl Remote app using their voice with any Alexa-enabled device. Additionally, the I-Pace can get over-the-air updates to its software in the fashion of the latest consumer electronics.

Considering the abundant reliance on electronics and software in the I-Pace, it was encouraging that during AE’s two days behind the wheel, the new infotainment system’s audio never went silent, as is typical of recent Jaguars and Land Rovers, whose radios suddenly stop playing and don’t resume until the car is shut off and restarted.

The I-Pace is on sale now, with a U.S. price of $69,500 to $85,900.

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