Final week, Lotus unveiled its Light-weight Electrical Automobile Structure, or LEVA, a extremely modular and mutable battery-electric structure that can function foundation for 2 upcoming sports activities automobiles and doubtlessly a 2+2 GT. To raised perceive LEVA, I reached out to Richard Rackham, Head of Automobile Ideas at Lotus.
“The construction is absolutely adaptable to offer a platform for a spread of EVs with variable layouts, wheelbase lengths, battery sizes and configurations,” says Rackham.
“Because the animation exhibits, all three layouts function a standard light-weight rear finish construction and suspension. This rear finish construction can accommodate propulsion items of differing complexities and efficiency, single or twin motor,” says Rackham. Identical primary rear construction, outlined attachment factors for motors and suspension arms, and an outlined technique for crash safety. From one structure, many automobiles. The identical kind of modularity is employed all through the structure, stem to stern, to ease improvement of inside parts like sprint, and readily change bodywork.
“The LEVA structure might be configured to accommodate two various kinds of battery: an underfloor slab [a variation on the now-classic skateboard] and a mid-mounted ‘chest.’ The batteries are of differing capacities relying upon the required automobile attributes and variety of occupants. All batteries are mixtures of a standard module,” says Rackham. For two-seat sports activities automobiles, the structure presents two wheelbase lengths and in addition smaller and bigger wells to carry the batteries immediately behind the passenger cabin. With the bigger battery, the rear construction will take twin electrical motors. The third variant is for an extended wheelbase 2+2 GT automobile, with the batteries laid underneath the ground, with the choice of a single or twin motor set-up.
“We assume 800 Volt or larger will probably be demanded in the course of the lifetime of the platform,” says Rackham, this being the usual Germans and different Europeans are working to. “An 800 Volt charging infrastructure allows quicker charging attributable to decrease connector present. For the HV techniques, the upper the higher, with the limitation being obtainable parts.”
In contrast to the $2 million Lotus Evija hypercar, which has a carbon-fiber construction, LEVA will depend on Lotus’s confirmed experience in extruded and chemically bonded aluminum constructions, pioneered within the extremely modern Lotus Elise greater than 20 years in the past.
“LEVA is an extruded and bonded aluminium chassis. The rear subframe makes use of a high-strength high-ductility BD1 aluminium compound developed as a part of the Mission LEVA collaboration by Brunel College London,” says Rackham.
“The benefit at Lotus is that we’re material- and process-independent. We’re not tied to utilizing a particular materials or manufacturing course of and can use what’s finest for the applying. It is a large benefit to our engineering consultancy shopper base and we’ll work with no matter course of or materials we’re required. Nonetheless, we pioneered the bonded and extruded chassis expertise in automotive functions and subsequently, there isn’t a different producer that is aware of extra about this than Lotus. For the LEVA program, this expertise and materials is one of the best resolution when it comes to weight, power, stiffness and effectivity,” says Rackham.
Lotus Managing Director Matt Windle stipulated that the battery of the sports activities automobile wanted to match the load of the prevailing supercharged 3.5-liter Toyota V6 used within the outgoing Evora and incoming Emira, an bold objective contemplating all of the engineers and scientists on the planet have but to ship the Holy Grail, a significant effectivity breakthrough in battery chemistry and packaging dimensions.
“We’ve got achieved that objective, however we’re nonetheless pursuing weight optimization of the battery so don’t have any definitive figures at this level. However it’s not simply the load of the battery, however the place it’s positioned,” says Rackham, and herein lies the promise of an distinctive light-weight and agile electrical sports activities automobile. Needless to say most electrical automobiles weigh near or greater than 5000 kilos. If the battery and electrical motor(s) weight is near the identical as an inside combustion engine, its gearbox and full gas tank, Lotus could have a sports activities automobile maybe akin to tremendous sports activities automobiles that weigh simply over 3000 kilos. Or at the least that’s the hope.
“For a sports activities automobile and our EV hypercar, the Evija, the battery is mid-mounted, the place the engine and gearbox can be in an inside combustion automobile. For the ‘chest’ battery behind the occupants the resultant automobile heart of gravity is additional ahead and decrease than that of a standard 3.5-liter V6. This offers the good thing about agility from the low polar second of inertia and signifies that the motive force and passenger will sit decrease, a significant notion for a sports activities, tremendous or hyper automobile. Nonetheless, LEVA can take each chest batteries and slab [underfloor skateboard] batteries all of various sizes for specific functions.”
With this positioning of the battery, weight distribution must be near optimum, and the automobile ought to change instructions with attribute Lotus immediacy. In accordance with Rackham, the mass and packaging of the battery, cabling and motor(s) approximates the load and bodily dimensions of a comparably highly effective inside combustion powertrain. If this proves true, Lotus could have extraordinary electrical sports activities automobiles.
It’s vital to notice that Lotus just isn’t utilizing a 2-speed gearbox within the Evija hypercar, which signifies that any future battery-electric Lotus sports activities automobiles won’t have the added weight of a gearbox. However right here Rackham won’t present definitive info, although within the video it’s laborious to see the place a 100-150+ pound gearbox is perhaps packaged. Purist sports activities automobiles for the street ship beautiful steadiness and a way of immediacy at speeds under 120 mph. A gearbox seemingly won’t be wanted.
“Lotus Evija is single velocity—we aren’t chasing 0-60 mph instances with the Evija, though it’s phenomenally fast over that dash. However the fee of acceleration from 60 mph to 120 mph and from 120 mph to 180 mph doesn’t change—it reaches 180 mph in lower than 9 seconds with every 60-mph acceleration interval being lower than three seconds.” Acceleration in Evija is unrelenting as much as 180 mph. However how a lot engineering cascades from Evija to the LEVA? One is carbon-fiber, the opposite aluminum-intensive.
“To start with, we now have been conducting superior R&D into EVs and hybrids as a part of the Lotus Engineering consultancy for a few years,” says Rackham. Keep in mind that the very first Tesla was primarily a Lotus Elise with a stretched wheelbase to accommodate the batteries. “Nonetheless, particularly from the Evija, we now have realized rather a lot in numerous areas of engineering and design, together with the environment friendly administration of air not simply over and across the automobile, but in addition via the automobile. This results in a lot better aerodynamic downforce and efficiencies and is made doable by the variations between EV powertrains and inside combustion when it comes to packaging.”
Proof is present in any examination of the rear fenders and rear panels of Evija, the place one notices monumental and punctiliously contoured tunnels that begin forward of the rear wheels and exit above the rear diffuser. One may mistake these “venturis” for exuberant design, the fellows with felt tip pens slightly uncontrolled. However the venturis provide aerodynamic benefit allowed by the compact bodily dimensions of electrical motors and the ahead placement of the batteries. They’re just like venturis seen on the Ford GT, however are far bigger, extra aggressive, and package deal higher than on the interior combustion Ford.
“We’ve got additionally a a lot better understanding of how energy and torque in EVs are utilized in comparison with an inside combustion automobile the place most torque is at decrease rpm. We’ve got realized how these excessive efficiency figures [of electric vehicles with 100 percent of torque available at 0 rpm, instantly] might be managed and optimized for one of the best driving expertise doable. We do stand ‘For The Drivers’ and this can be very vital that we proceed to offer one of the best and most fulfilling driving expertise in every part we do!” Managing torque supply and in addition torque vectoring, that means how a lot torque is utilized throughout the axles to the person wheels—left to proper, to the within and outdoors pushed wheels throughout cornering—has been an engineering and scripting exploration amongst all electrical automobile makers. The power to meter torque at each the motor itself immediately and precisely at every wheel underneath all cornering circumstances can result in great beneficial properties in dealing with. Mix that with the confirmed technique of making use of millisecond touches of braking to particular person wheels to stop lack of traction and a automobile can obtain virtually cat-like steadiness—how terribly Lotus.
In contrast to the newest European high-performance electrical automobiles, Lotus doesn’t intend to make use of motors on the entrance wheels, at the least for now. “Entrance motors are being thought of, however we now have to guard the basic Lotus rules of sunshine weight, agility and steering really feel,” says Rackham, the identical argument that applies to make use of of a 2-speed gearbox. This differentiates Lotus from Rimac, Pininfarina and probably the most aggressive all-wheel-drive Porsche Taycans. Clearly the objective is to retain purity of steering really feel and hold automobile weight as little as doable.
In LEVA, Lotus has additionally outlined their battery technique for his or her first-generation of electrical automobiles.
“A typical battery module is used all through; the variety of modules varies to swimsuit the required efficiency. The ‘slab’ configuration is the smaller block laid flat,” says Rackham. That is proven within the animation, the battery laid out flat immediately underneath the passenger cabin, a variation on the now-classic skateboard.
“LEVA will be capable to accommodate different modules as battery expertise develops. We received’t give away the load distribution but, however we will say that in recent times all our automobiles have been mid-engine and have round 40:60 entrance to rear and that’s definitely one of the best resolution,” says Rackham.
“Lotus is at all times about innovation, not simply evolution. With our high-level backing from our shareholders, we now have the sources and experience to lean on the globally influential and quickly rising Geely,” says Rackham. “There’s a large enthusiasm and want from the worldwide marketplace for Lotus to diversify past sports activities automobiles, and whereas the sports activities automobiles are very important to the enterprise, we could have an expanded product vary to incorporate SUVs and sedans and these are already in improvement and the primary of which can come out subsequent yr—2022. It’s a very thrilling interval forward, however that is now a actuality which Lotus has been working in the direction of during the last 73 years.”