Last night, Elon Musk took the wraps off the new Tesla Model S. Dual motors and all-wheel drive don't just make it faster, a new sensor array will make it safer too. Let's break out each innovation, figure out what it is and how it works.
Dual Motors: Putting the "D" in the Tesla Model S P85D, an electric motor has been added to the front of the car, driving those wheels. Previously, the Model S was rear-wheel drive only.
That motor develops 221 bhp, taking the car's total power up to a supercar-like 691 bhp. Combined torque is even more impressive at 687 lb-ft, growing from 362. The additional motor and its associated hardware adds 291 lbs of weight, taking the top-of-the-line P85D's total weight to 4,936 lbs.
To put those numbers in perspective, the insane new Dodge Challenger Hellcat makes 707bhp, 650 lb-ft and weighs 4,449 lbs. The Tesla is faster to accelerate, reaching 60 mph in 3.2 seconds to the Hellcat's 3.7 second time. The electric car is limited to a top speed of 155 mph, so will eventually be outrun by the 204 mph Internal Combustion Engine car.
The two motors powering the all-wheel drive Model S are visible in red.
Adding an electric motor to drive the front wheels is a vastly different approach to equipping an ICE car with a transfer case and All-Wheel Drive. Linking the front and rear wheels to the engine in an ICE car involves adding much weight and complication through an additional driveshaft, an arrangement that also limits the proportion of power that can be directed to either end, the speed at which that proportion can change and the degree of fine drive control that can be established. Electric drive systems in general can be controlled to a much finer degree and the D's will be able to function completely independently of each other, vectoring torque to individual wheels in an ideal, instantaneous manner. This amount of control over motive force is an engineer's wet dream. As Musk says in his presentation, it even increases road-holding, taking the four-door sedan up to a full g on the skidpan. That Hellcat? MotorTrend measured its lateral acceleration at just .94 g.
Of course, all-wheel drive will enhance the Model S's capability in inclement weather too, an important factor to the large number of luxury car buyers in the Northeast and something which will more fully enable Tesla to conquest sales in that market from established players like Mercedes, Audi and BMW.
Long range radar (green), an image recognition camera (light blue), 360-degree ultrasonic sonar and satellite data all inform both autopilot and the driver.
Autopilot: Musk says that Tesla is still five to six years away from a true, self-driving car. And regulations currently don't permit use of such vehicles on the road, away from development allowances in California and Nevada. Instead, Tesla has fitted all new Model Ss with a sophisticated array of sensors intended to better inform the driver of conditions around the car and which can take some limited control to avoid crashes.
There's four components to the Autopilot system:
Long Range Radar: This looks ahead of the Model S, identifying the presence, direction of travel and relative speed of other cars. It can see further than the car's headlights and cut through fog, rain or any other visual impairment.
Image Recognition Camera: This also looks ahead of the car, identifying and reading things like traffic signs, lane markings and pedestrians.
360 Degree Ultrasonic Sonar: Looking all-around the car, this sensor is able to detect everything from cars in your blind spot to a stray pet about to run into the road, to a child playing behind you as you're backing up; a soft-object capability the forward-facing long range radar does not have. Consider that a boon to motorcyclists too, Autopilot should be able to stop homicidally negligent car drivers from running us over!
GPS Data Integration W/Real-Time Traffic: Location based data is beamed to the car, informing it with a database of speed limits and traffic/road conditions.
All that data might sound overwhelming, but it's presented to the driver through the Model S's slick, simple information display. You can then use it to inform your decision making while driving or, if necessary, the car can step in to aid you.
Together, Autopilot brings Tesla up-to-date with new European safety regulations and compresses a vast amount of data into a simple, visual display informing the driver of hazards. It also give the car some element of self-driving, enabling it to check blind spots, then switch lanes when it's safe to do so itself if you've activated the turn signal while on the highway. It can also auto-brake if it detects traffic is slowing or stopping ahead or if a hazard suddenly appears, such as that pet running out into the road. Musk mentions that the system is now capable of emergency braking, taking advantage of the car's full braking performance if necessary. The drive system, brakes and steering are now all fly-by-wire (well, the sterring is an electrically assisted mechanical arrangement), enabling both faster actuation than traditional hydraulic or mechanical systems and, of course, allowing the car to take control when necessary.
While in Autopilot, the car can also read traffic signs like stop signs or lights, or speed limits — the latter also informed through that GPS data — to keep you within the realm of safety and legality.
It's not self-driving, yet, but it is a huge degree of driver assistance, giving you better information with which to make decisions and stepping in to save your ass if you're not paying attention or if an environmental condition is limiting vision. It should make highway driving a more relaxing affair for you as well, taking much of the guess work out of cruising along at a steady speed through traffic doing otherwise.
Musk says the sophistication of these abilities will be developed over the next few years through software updates that will roll out to all models equipped with Autopilot sensor hardware.
With little fanfare and a car that looks exactly the same as before, it's easy to walk away from this new model presentation nonplussed. You shouldn't. Tesla is in the business of driving automobiles towards their next evolutionary step; adding significant levels of both safety and performance is a leap forwards, achieved while making substantial progress towards cutting the human out of the driving equation altogether.