Take a good look at Renault's light and aerodynamic EOLAB hybrid concept, because it's innovations will make it into production very soon, maybe even as a Nissan.
The EOLAB (in case you're wondering, a combination of the name of 'Aeolous' God and Ruler of the Winds in Greek mythology, and 'Laboratory') is a 235 mpg car. That's right.
Let's start with weight. It's 882 pounds lighter than the equivalent (hybrid) Renault Clio, which happens to be around 2,300 pounds. The roof is made of magnesium, the windshield is half as thick as the current norm, the side windows use laminated glass (instead of tempered) while non-moving windows are made of polymers used in the optical glass industry. The rear screen also uses polymers instead of tempered glass, also incorporating the rear lights. Clever.
While all-aluminum and aluminum-carbon fiber cars already exist, Renault says that's not good enough for keeping the price right in the B-segment:
In addition to the high cost associated with such materials, they often necessitate an in-depth review of assembly and production processes, and there is a price to pay for that. Our strategy is to reduce weight in a way that benefits everybody. That means finding economically viable solutions that our customers can afford. Our approach can be summed up by the phrase: 'the right material for a given job'."
So, the EOLAB's body shell combines steel, aluminum, magnesium and plastic composites. The steel in question is the hot stamped Very Very High Elastic Limit variant, which has a yield strength of between 1,200 MPa and 1,500 MPa, an improvement of between 200 MPa and 500 MPa over the VHEL steels used for current Renault models.
The cast or sheet aluminum parts are also warm stamped instead of being hot stamped in order to make them as thin as possible while keeping their strength. The rear circumferential chassis member is also made entirely of aluminum, which helps when it comes to thermal expansion during the paint curing procedure.
Sheet magnesium is used for the roof, cowl panel and parts of the seat frames, mostly because it's light and corrosion-free but also much cheaper than titanium. Renault says some cars already feature magnesium but only for moulded parts made from magnesium powder (e.g. the majority of the market's steering wheel armatures), so using sheet metal to half the roof's weight is kind of a big deal.
When it comes to plastics, the demo car's front, rear and central floor pans, B pillars and lower cross member are all made from hot-stamped composite thermoplastic, while the skins of the one-piece wings/bonnet assembly and doors are made from injection moulded thermoplastic. Structural components use longer glass fibers, and Renault claims these plastics are easier to recycle than thermoset resins.
20 percent of the weight savings comes from the running gear. Replacing steel with aluminum means a lighter subframe, suspension arms, hub carriers and rear arms. And they didn't stop there:
Normally, programmed chassis deformations affects three areas in an impact: the upper part of the chassis, the side members and the lower part of the chassis). In the case of EOLAB, the latter's 'add-ons' were eliminated but this was compensated for by relocating and strengthening the side members. The resulting saving was between seven and eight kilos. We also looked at making the springs from a glass fibre/thermoset plastic composite, which would have produced a saving of three kilograms. Using a different composite for the rear beam would have saved another three kilos or so, too.
The brake system is 32 pounds lighter than the Clio's. Renault got rid of the master cylinder and integrated all systems into one unit. The front brake discs are smaller and combine steel and aluminum. Basically, the the part of the discs in contact with the pads is made of steel, while the central part is made of the lightweight alloy. The same recipe was used for the rear drums, where the friction zone is cast steel while the rest of the drum is aluminum.
Unfortunately, the manual parking brake is also gone, saving another 2.86 pounds in the process.
Inside, the seats are made of lighter metals and cushioning while the textile uses an embedded pattern in order for the cover to match the seat back's forms as closely as possible, improving rear legroom.
Plastic fittings are also thinner with injected foam with air bubbles while the boot trim uses a sandwich structure comprising a foam insert between the two outer surfaces. The Clio's compact polypropylene air intake ducts where replaced by expanded polypropylene parts. Renault had to rethink the car's architecture since those ducts are five times thicker than the standard plastics, but also 5 pounds lighter in total.
The French companies own hybrid drivetrain consists of a three-cylinder, 999 cc gas engine producing 75 horsepower and 70 foot pounds mated to a clutch-less three-speed transmission instead of a CVT or a dual-clutch unit, plus a permanent magnet electric motor in the clutch housing capable of 53 horsepower and 147 ft lb.
With a 6.7kWh battery on board, the EOLAB has an all-electric range of 37 miles. In this case, the car will stay in first gear up to 40 mph, and keep things all electric in second as well with a top speed of 74 mph.
If you want to go faster, third gear will automatically wake up the internal combustion engine. You can also choose it to come alive at lower gears as well, giving you all the power in what they call "Weekend Mode".
Needless to say, the EOLAB is also as aerodynamic as a raindrop. 0.235 Cd means it's 30% sleeker than the current Clio, which isn't exactly a brick to start with.
It also uses extremely narrow 145/45R17 Michelins, an active air suspension like a Veyron, active spoilers, aerodynamic flaps and wheels that get covered whenever the sensors built into the rims report that the brakes do not need cooling. Bonneville!
The final number for this five-seater subcompact?
2,105 pounds, 235 mpg (on the EURO cycle).
And Renault says the nearly 100 technological innovations seen on the EOLAB are all production-destined, appearing gradually on Renaults (and Nissans?) before 2020. I'm guessing the fixed hood won't make it.
So, would you rock that?