► Alpine’s new electric cars are quite heavy
► But the brand has engineered around the problem
► We break down the company’s new chassis tech
Alpine has built its brand on two pillars – lightweight engineering and nimble handling. But the company might be forced to take a sledgehammer to those pillars because they aren’t yet compatible with electric cars.
Automotive engineers haven’t yet worked out how to strip enough weight out of an electric car’s battery pack to make it handle as keenly as an equivalent petrol car and maintain a convenient maximum driving range.
But Alpine seems to think it can engineer its way around the problem with some clever torque-vectoring tech and chassis tuning designed to hide the weight of its new electric cars. These physics-defying silver bullets were introduced on the 2.1-tonne A390 SUV and they’ll also feature on the upcoming all-electric replacement for the A110. Scroll down to find out how it all works.
How Alpine’s new torque vectoring tech works
The Alpine A390 is based on the Renault Group’s AmpR Medium platform (the same as the Renault Scenic), albeit with several improvements. Instead of a single electric motor up front, it has three – one for the front wheels and two at the rear.
The rear motors can spin independently of one another. Effectively, that means Alpine can use them to steer the car from the rear using torque. So, when you pitch the A390 into a corner, the outside wheel spins faster than the inside one, pushing the rear of the car around the bend like a skid-steer. As the video below shows.
But it gets cleverer than that, because all three motors are receiving a constant stream of information from the car’s steering rack and traction control system. The motors can adjust the torque split both front to rear and left to right depending on the amount of understeer or oversteer the car is experiencing.
I’ll break it down. You’ve approached a corner at Mach 4. You’ve left it far too late to brake and you’ve overwhelmed the front tyres. You’re starting to understeer. The car’s computer senses your impending calamity and feeds power to the outside rear wheel to kick the arse of the car out and correct your mistake. Once it’s gathered it up, it’ll send power to all four wheels equally to catapult you down the next straight.
The inverse is also true. Say you’ve pushed too much weight onto the nose of the car on your way into a corner with heavy braking and the rear end is starting to step out of line. The computers will back the power off the rear outside wheel, send a dab of power to the rear inside wheel to stop the car rotating further and use the front motor to get the car tracking straight again.
Alpine claims the speed at which this torque vectoring technology can adjust the balance of the chassis mid-corner will make the A390 ‘feel’ lighter than it is by masking its inertia and tricking your brain into thinking the car is more playful than its weight would suggest.
What else has Alpine done to cheat physics?
The trickery doesn’t end there. Alpine’s engineers fitted the A390 with fast steering (which it reckons further helps to hide the car’s bulk), unique adaptive dampers and clever hydraulic bumps stops that were designed to better slow your descent when you drop the car into dip on the road.
A big compression over a dip (followed by a clatter into the bump stops) is a key part of what makes a large EV feel heavy, simply because well-maintained petrol cars don’t exhibit that behaviour. It’s unfamiliar. Petrol cars tend to weigh less and so they accelerate more slowly into the ground over undulating surfaces.
By slowing that descent at the extremities of the car’s suspension travel with what’s effectively a second damper, Alpine hopes the A390 will feel more like a 1.6 or 1.8-tonne car rather than 2.1-tonne car. Think of it like a bungee jump – when you reach the end of your travel, the elastic goes taught and you’re hauled up gently rather than hitting the earth below with a crunch.
Not only should that prevent the chassis from become unsettled when it reaches the limit of its travel, it should also maintain ride comfort. No other manufacturer has nailed this balance yet – not even the class leaders.
Hyundai, for example, could have improved the way the Ioniq 5 N controls the heft of its battery with some cast-iron dampers, but they would have made the car untenably uncomfortable on your morning commute.
I’m certainly looking forward to trying Alpine’s chassis tech for myself. I’ll report back once I’ve got some first-hand experience to tell you whether it’s worked.