Formula E Brings Glamour to Zero-Emission Motoring

FIA-sanctioned street-circuit race series showcases electric vehicle performance and promises to overturn sector's dull image

Electric vehicles (EVs)—cars driven by one or more electric motor powered by batteries recharged from an external electricity supply—suffer from an image problem. Compared to the perception of limitless power projected by a growling Detroit V8 or the higher-pitched hum of a European sports sedan's inline 6 cylinder gasoline engine the barely audible whine of a Nissan Leaf's synchronous electric motor doesn't really cut it for glitz.

Reinforcing the less-than-glamorous reputation of the EV is the typically nondescript range of models on sale. There's little to get the heart racing from among the top sellers in the U.S. market. Between them, GM's Chevy Volt, Nissan's Leaf, Tesla's Model S, and the plug-in version of Toyota's Prius make up 80 percent of sales of the 225,000 EVs sold in the U.S. since the beginning of 2011. Ford's Fusion Energi and Mitsubishi i-MiEV are also popular. Yet all, bar the upmarket Tesla, are low- or mid-range, understated (if capable) vehicles that barely raise a second glance— and then only because of the unexpected near-silence as they cruise past.

And yet, beneath the modest bodywork the modern EV is a sophisticated vehicle with technology on a par with any conventional vehicle coming out of Michigan, Bavaria or Greater Tokyo.

For example, the relatively modest Nissan Leaf's motor produces 80 kW (110 bhp) and 280 Nm (210 lb•ft) of torque using the resources of a 24-kWh lithium-ion (Li-ion) battery pack. This power is sufficient to propel the vehicle from 0-to-100 km/h (0-to-62 mph) in ten seconds, not too shabby for a compact five-door hatchback with an Environmental Protection Agency (EPA) combined fuel economy rating of 115 miles per US gallon gasoline equivalent (2.0 l/100 km).

But such figures mean little to the man in the street when it comes to choosing his next car. What really pulls in the punters—as the automotive industry's marketing men know only too well—is a brand's association with motorsport. Seeing your car of choice's badge on a high performance vehicle winning Indycar, Formula 1 or World Rally Championship races is a powerful incentive to buy than the small print of a spec sheet.

And now EVs have their own global showcase, an official FÃ © Details © ration Internationale de l'Automobile (FIA — the governing body of motorsport) single-seater championship which commenced in Beijing in September and will continue through to June 2015. The championship will compete in the heart of 10 of the world's leading cities - including London, Miami, and Buenos Aires in addition to Beijing. Ten teams, each with two drivers, will compete in a high performance EV - the Spark-Renault SRT_01E.

But Formula E is not just about glamorizing EVs; according to Alejandro Agag, CEO of Formula E Holdings, the championship will become "the framework for research and development around the electric car, a key element for the future of our cities." Just as technologies such as double overhead camshafts, four-valves per cylinder, and anti-lock brakes were either invented or perfected in motorsport and then trickled down into conventional road-going vehicles, Formula E organizers hope their sport will do the same for EVs.

Leading-edge Technology

The first Formula E race in Beijing proved to curious motorsport fans that the series is not a gimmick. The fiercely competed event was won by ex-Formula 1 driver Lucas di Grassi for the Audi Sport ABT team. di Grassi averaged 127.5 km/h (79.2 mph) for the 52-minute race. In second place was former Renault F1 test driver and Formula 3 competitor Franck Montagny for the Andretti team who was just 2.9 seconds behind the winner.

While excellent, the performance of Formula E cars comes as little surprise to automotive engineers working on commercial EV designs. Although most modern EV use Li-ion power packs whose volumetric energy density of around 700 Wh/l is well below that of gasoline (10 kWh/l.), the vehicles have several factors in their favor beyond a lack of noxious exhaust fumes. Key among these advantages is the efficiency of an electric motor compared to a gas engine (75-to-85 against 25-to-30 per cent for conversion of electrical/chemical energy into mechanical energy to drive the vehicle forward.) Second, the fact an EV's electric motor is more compact than a gasoline engine, frees up space for more batteries and hence greater energy capacity. (Fig. 1.)

Figure 1:EV electric motors, like this unit used in BMW's i3, are light and compact. (Courtesy: BMW)

Nonetheless, comparison of a mid-range EV and its conventional equivalent shows that the gas-powered car offers greater overall performance and range. Much of that is down to the over 130 years of intensive development to which the internal combustion engine has been subjected. Although the EV itself is older than many people imagine—battery-powered vehicles date back to at least the 1830s and possibly even earlier—it is only in the last 20 years or so that the major automobile manufacturers have directed their enviable resources into intensive EV development.

The result is that EVs are catching up fast with gas equivalents. Tesla's latest product, the Model S, for example, is a rear wheel drive EV that calls on the resource of an electronically managed 60- or 85-kWh Li-ion battery pack. The Model S incorporates a liquid-cooled powertrain culminating in a three phase, four pole AC induction motor with copper rotor mounted in the middle of the rear axle that is capable of driving the 2100-kg (4630-lb) vehicle at up to 210 km/h (130 mph) with a range of up to 425 km (265 miles.) Other features of this sleek machine include a drive inverter with variable frequency drive and regenerative braking system that recharges the batteries with energy harvested from deceleration.

A gas engine produces little torque and power at low revs, dictating that it must work through a series of gears to allow the engine to build up revs quickly if decent acceleration is to be achieved. And even then, maximum power and torque are restricted to a relatively narrow peaks, with maximum torque coming about half way through the rev range and power reaching a high point towards the top of the engine's rev capability, necessitating frequent gear changing to cater for varying road conditions (Fig. 2). In contrast, an EV delivers all its torque immediately and continues to provide it smoothly only tailing off marginally in the upper rev range. Similarly, power from an electric motor also builds smoothly across the entire rev range and hardly tails off even towards the unit's upper limit (Fig. 3).

Because of the way an electric motor produces its power, an EV with lower nominal performance is often just as quick off the line and as a more powerful conventional vehicle. The Model S, for example, has a 310 kW (416 bhp) engine producing 600 Nm (443 lb•ft) which propels it from 0-to-100 km/h (0-to-62 mph) in 4.2 seconds. That's superior acceleration than a BWM M5, a high-performance European sports sedan which is of similar size and slightly lower weight (1945-kg (4288-lb)) than the Model S but features a 418 kW (560 bhp), 680 Nm (500 lb•ft) gasoline engine.

Formula E(ntertainment)

While Formula E was born out of FIA's desire to promote the laudable values of clean energy, mobility, and sustainability perhaps the most tangible benefit of Formula E will be its role as a test bed for EV technology that will stimulate further battery, drivetrain, motor, and engine management.

The cars are quick—reaching 100 km/h (62 mph) from a standing start in 3 seconds and going on to a maximum speed of 225 km/h (150mph.) For qualifying, drivers will be able to employ the full 200 kW (270 bhp) potential of the powertrain. However, during races, in order to extend the battery lifetime to around 30 minutes, the maximum power is restricted to 150 kW (203 bhp) - with limited use of an additional 30 kW (40.5 bhp) for overtaking.

That's not to suggest that the 2014 championship will be boring. FIA is pulling out all the stops in its attempt to project Formula E as an entertaining spectacle to enhance the image of EVs in the public's perception.

For starters, the grid is not short of talent. Thirteen of the twenty drivers contesting the event have competed in Formula 1 and will be racing to win. A spectacular final corner incident in the first race that ended with Nick Heidfeld's (a regular Formula 1 podium finisher) Venturi coming to a halt upside down after colliding with Nicholas Prost's (a Lotus F1 test driver) Renault underlined the drivers' competitive edge.

The drivers compete for 10 teams that include names familiar to racing fans such as Audi, Andretti, Renault, and Virgin, as well as some newly formed Formula E teams such as China Racing, Dragon Racing, and Mahindra Racing.

Naturally, the cars the teams use employ the latest EV technology; for example the McLaren electric motor driving the wheels has the highest power-to-weight ratio of any electric motor in the world, delivering up to 200 kW (270 bhp) for qualifying from a motor weighing just 26 kg (7.7 kW/kg). In comparison, the 1.5-liter V6 engine used for the 2014 Formula 1 season produces 450 kW from an engine weighing about 120 kg (3.75 kW/kg).

Every team will base their entry on the Spark-Renault SRT_01E built by French company, Spark Racing Technology, together with a consortium of some of the leading companies in motorsport. But that's not to say all the cars will be identical. The teams are free to tinker with the power management software, for instance, to determine how best to manage battery energy during the race, providing they don't exceed the restrictions detailed in the rules. Each battery pack incorporates a master control system that monitors the voltage and temperature of each cell to see if anything unusual is happening. Engineers can choose to shut down cells or limit the battery pack's output to keep temperatures down or extend the range at the cost of outright performance. Such strategies are analogous to those employed in Formula 1 to save fuel and limit tire wear.

Italian firm Dallara supplies the monocoque chassis, fabricated from carbon fiber and aluminum, which complies with the latest FIA crash tests - the same used to regulate Formula 1. Providing the electric powertrain and electronics is McLaren Electronics Systems while another company known for its involvement with Formula 1, Williams Advanced Engineering, supplies the batteries. The batteries use the Lithium Ion (Li-ion) chemistry favored by manufacturers of mid- and high-end commercial EVs. Li-ion offers the best energy density of any battery technology and is quick to recharge. The battery pack weight is limited to 200 kg (to encourage future improvements in energy density) and delivers 28 kWh. A five-speed paddle shift sequential gearbox, supplied by Hewland, transmits power.

Systems integration is supervised by Renault, a leading supplier of EVs and a company with major investment in motorsport via its Renault Sport Technologies and Renault Sport F1 programs. The cars stick to the road thanks to specially designed 46-cm (18-in) treaded tires supplied by Michelin.

In addition to Beijing, races will be conducted over street circuits of 2.5-to-3 km (1.6-to-1.9 miles) in length. The circuits include Long Beach and Berlin, and even the iconic Monaco Formula 1 circuit (although the Formula E race will not use the full-length Grand Prix course.) Races will commence from a standing start and will last for around 55 minutes. Because the batteries only last about 30 minutes at racing speeds, drivers will be required to pit and change to a second (fully-charged) car for the second half of the race. An FIA steward observes changeovers to ensure all safety equipment is correctly applied and a minimum time period for the swap is enforced.

Using just one car and recharging part-way through the race is currently not practical because a full charge takes about 50 minutes. Similarly, swapping out exhausted battery packs for fresh ones is impractical because the battery packs are hidden behind shield to protect drives from the possibility of battery ignition in the event of a crash.

Like any high profile motorsport events, the Formula E race series is attracting its fair share of sponsors, keen to be associated with the glamour and glitz as well as helping to support an event dedicated to raising the profile of EVs and improving their technology.

Leading electronics distributor Mouser, a firm that, among other areas, has specialized in the supply of high-tech solutions for automotive engineers for many years, is proudly lending financial support to the China Racing Formula E Team and displaying its logo on the nose cone of the red car. Mouser is joined in its sponsorship of China Racing by leading electronic component companies, Vishay, a leading supplier of semiconductor and passive components, and Molex, a leading provider of technology ranging from connectors to cable assemblies.

Figure 4:China Racing's Formula E racecar, sponsored by Mouser, Vishay, and Molex, accelerates hard at the first event in Beijing. (Courtesy: Formula E)

Formula E has gone from concept to fully fledged race series in just three short years, and while the cars are currently slower than their gasoline-powered equivalents, the gap is sure to narrow as the technology is forged in the white-hot heat of competition. That technology is destined to make its way into road-going EVs, enhancing their appeal and boosting the number of zero-emission vehicles on U.S. roads to over 1.1 million by 2022, according to industry analysts.