Twizy Renault Sport F1 is a racy EV that defies categorization

Thu, 25 Apr 2013

It recently came out that Porsche mulled a return to Formula One but chose a return to Le Mans instead, citing F1 technology's lack of relevance to its road cars. Well Porsche, take this: the Twizy Renault Sport F1 concept, "a bridge between the world of F1 technology and that of production cars." The French Formula One legend took a 17-horsepower electric Twizy and replaced the back seat with an 80-hp KERS unit, just like the ones it produces for its F1 customer teams. Then it added tires from a Formula 2 Renault and a steering wheel derived from a Formula 3.5 Renault, a front splitter, sidepods and open-wheeler mirrors. Yes, it's absurd – and by absurd we mean outstanding.

There are two KERS modes the driver can use, the first a Recovery mode that uses the Twizy's main 17-hp electric motor to recoup energy since the city car can't produce enough energy through braking to repower the KERS unit. The other is Boost mode, which allows a 13-second burst using the combined 97 horsepower available with the two motors. A single-seater-style rain light is affixed out back, and it illuminates when in Boost mode. The result is a Twizy that can dash from 0-60 miles per hour as quick as Renault's fastest car, the Megane Renaultsport 265, listed by Car magazine at six seconds. The Twizy's top speed in Boost mode climbs from 53 mph to 68 mph.

It will be shown at various events throughout the year, starting with the World Series by Renault race in Aragon, Spain on April 27 and 28. You can read all about it right now in the press release below.

TWIZY RENAULT SPORT F1 CONCEPT: IMPROBABLE AND SPECTACULAR

25/04/13 -- Renault has chosen the Twizy manufacturing plant in Valladolid, Spain, to present its new Twizy Renault Sport F1 concept car. This fun take on the brand's electric urban compact features muscular styling and impressive performance credentials to serve as a bridge between the world of F1 technology and that of production cars.

Twizy Renault Sport F1 sits on the wheels of a single-seater race car and is equipped with a front splitter, side-pods, rear wing and a diffuser complete with an F1-style rain light which forcefully express the concept's ties with motor racing's premier category.

Twizy Renault Sport F1 is much more than just a concept. In addition to its spectacular looks, it delivers genuine high performance thanks to its Kinetic Energy Recovery System (KERS) which is identical to the solution used by Renault-powered Formula 1 cars. The system instantly boosts power output six-fold to reach almost 100 horsepower and is capable of catapulting the car from standstill to 62 mph as quickly as Renault's highest-performing road car, Mégane Renaultsport 265. This technological gem is the fruit of close collaboration between the engineers at Renaultsport and their colleagues at Renault Sport F1.

This extraordinary vehicle showcases Renault's advanced expertise in electric technology employed in F1, notably in the field of KERS in which it was one of the precursors in 2009. Renault's long-standing commitment to motor racing's blue ribband category provides it with a unique technological laboratory, giving it an advantage not only in the world of race cars, but also in that of road cars.

Twizy Renault Sport F1 will be shown at major events throughout the year, beginning with its first public appearances at the World Series by Renault meeting at Aragon, Spain (April 27-28), followed by the Barcelona Motor Show.

I. F1 TECHNOLOGY APPLIED TO TWIZY

"We always said we wanted to create F1-derived technology that was road relevant! Hopefully, this Twizy will make a few people smile while also making a serious point. The project was led by Renault Sport F1 and Renault Sport Technologies, working in close conjunction with Renault's electric vehicle development department. KERS is a very complex system and integrating it into another electric vehicle was a very serious endeavour, but they managed to make it work, delivering a huge boost of power safely and efficiently. I'm not sure we'll be seeing many of these on our roads, but it does show that the same principles we see on the race track can be filtered down to the road legal range – this is just the evil elder brother!"
- Jean-Michel Jalinier (President and Managing Director, Renault Sport F1)

1. Small but tough: a spectacular look inspired by Formula 1

Twizy Renault Sport F1's calling is immediately apparent through its slick tyres (the same as those fitted to the Formula Renault 2.0 single-seater), as well as through its carbon splitter, side-pods and rear wing. Its unique proportions give it the appearance of a beast that is about to pounce yet which is still fun to drive.

Other features derived from the racing world are its single-seater type mirrors and diffuser, which incorporates the rain light of a Formula Renault 3.5 car. At the same time, the bulbs of the lights have been replaced by LEDs which, again mirroring the world of motor sport, consume less energy.

Meanwhile, Twizy's rear seat has made way for the KERS which is visible inside a transparent housing. Last but not least, Twizy Renault Sport F1 is equipped with an F1-type steering wheel from the Renault Sport Technologies catalogue.

"Twizy Renault Sport F1 is a simple, yet smart, vehicle which combines original lines and advanced technology derived directly from Formula 1. Our objective was to reinforce Twizy's 'fun' side by using F1 cues to express its personality. In terms of both its look and performance, the result is quite simply spectacular."
- Eric Diemert (Design Director, Renault Sport Range).

In order to express the link with Formula 1 and the Renault Sport race car range, both Renault Sport F1 and Renault Sport Technologies contributed to Twizy Renault Sport F1's design.

"As far as styling was concerned, we wanted to avoid falling into the trap of simply producing a steroid-fed Twizy. We therefore worked closely with Renault Design to find a way of incorporating Formula 1 cues on a vehicle of this size. Although Twizy's forms clearly distinguish it from a single-seater race car, you can see numerous echoes of the world of grand prix racing."
- Tarik Ait Said (Project Coordinator, Twizy Renault Sport F1).

2. A Twizy boosted by F1-derived technology

Twizy Renault Sport F1's performance credentials are founded on the use of the KERS employed by Renault-powered Formula 1 cars.

The KERS (Kinetic Energy Recovery System) is designed to recover some of the kinetic energy which is generated under braking. Instead of being lost in the form of heat, this energy is recovered and stored before being used to momentarily boost power output, just as it is in Formula 1.

The KERS comprises three main elements:
- An electric motor-generator unit (MGU) directly linked to the driveshaft.
- Specific lithium-ion batteries.
- A KERS Control Unit (KCU).

Mechanical energy -> electrical energy -> chemical energy
As its name implies the motor-generator unit serves as both a generator and a motor. In 'generator' mode, it functions like a dynamo to convert mechanical energy into electrical energy which is then stored in a battery. To use this energy, it suffices to reverse the process. The system then switches to the 'motor' mode to use this stored energy to deliver a power boost to the wheels via the motor.

Six times the power output!
Twizy Renault Sport F1 is consequently equipped with two electric motors, i.e. Twizy's original motor (17hp/13kW) onto which an F1-style KERS has been grafted to turn the concept car into a genuine pocket rocket with exceptional performance.

When the KERS is activated, Twizy Renault Sport F1's power output climbs instantly six-fold, from 17 to 97 horsepower (72kW). This boost is available for approximately 13 seconds, just as it is in the case of a Formula 1 car. Thanks to this additional power, the concept car is capable of accelerating from standstill to 62 mph in the same time as Mégane Renaultsport 265.

Adapting KERS for Twizy
It goes without saying that Twizy Renault Sport F1 isn't as fast as a single-seater race car. As a consequence, the kinetic energy produced under deceleration is insufficient to charge the KERS' battery. To get round this problem, the experts at Renault Sport Technologies and Renault Sport F1 developed a system that enables the battery to be charged by siphoning power from the main motor. This solution gives the driver total independence over how the KERS is used.

The driver can choose between two modes for the KERS used for Twizy Renault Sport F1, using the controls located on the steering wheel.

1/ Recovery mode: with this mode activated, the electric motor functions like a conventional generator, drawing power like a dynamo to convert the mechanical energy produced by Twizy main motor into electrical energy. Up to 4kW can be siphoned off in this way to charge the battery while on the move.

2/ Boost mode: the energy recovered using the Recovery Mode can be re-employed whenever the driver wishes by pressing on the button located on the steering wheel. This reverses the process. Instead of serving as a generator, the KERS' motor-generator unit (MGU-K) now functions as a motor to bring a power boost to the principal motor to which it is directly linked via the driveshaft. The maximum power output of the MGU-K is 60kW (approximately 80hp).

The charging process and the way the stored energy is delivered are controlled by a control unit which is itself linked to Twizy Renault Sport F1's ECU (Electronic Control Unit).

When the system is triggered, the maximum revs of Twizy's motor rise to 10,000rpm for a top speed of 68 mph. The fruit of advanced technology, the MGU-K fits inside a 10cm-diameter cylinder and can rev to as high as 36,000rpm. The KERS is equipped with its own battery capable of very short charge/discharge cycles. Derived directly from F1 technology, the package weighs barely 30kg, battery included.

Given that the peak revs of the KERS and Twizy's principal motor are 36,000rpm and 10,000rpm respectively, the connection between the two was one of the chief challenges of the project. Synchronisation is ensured by a 1:3.6 reducer gear which uses the same drive gear as that of the F1 V8 engine.

The KERS uses a pressurised lubrication system to enable certain bearings to withstand peak revs of 36,000rpm. Meanwhile, in order to prevent the KERS battery from overheating despite the constraints to which it is exposed, Twizy Renault Sport F1 is equipped with water cooling. Both these systems are existing Renault Sport Technologies solutions.

An F1-type steering wheel derived from Renaultsport's race car range
Twizy Renault Sport F1's steering wheel is derived directly from that of the Formula Renault 3.5 race car. Its functions have been adapted for use on an electric vehicle equipped with KERS, while the rim is of a wider diameter.

The amount of energy recovered while the Recovery mode is activated can be adjusted using the four-position rotary knob. Another rotary knob enables the power boost to be set at one of six pre-set levels, ranging from 10 to 60kW.

The driver releases the energy stored by the KERS by activating the two steering wheel-mounted paddles at the same time. To show spectators that the system has been activated, the rain light incorporated in Twizy Renault Sport F1's diffuser is switched on.

The concept comes with its own data logging system, with information displayed on a multi-page screen situated on the steering wheel. This display can be personalised to show information concerning both Twizy's and the KERS F1 electronic systems.

A wide range of parameters can be displayed in real time, including the main battery's level of charge, the KERS battery's level of charge, oil pressure, water temperature, etc.

Twizy Renault Sport F1 is also equipped with an 'RS Monitor' data logging system similar to the one available for Mégane R.S. and New Clio R.S. 200 EDC. This allows the driver to monitor a number of performance-related parameters in real time (0-31 mph time, 0-62 mph time, 50- and 100-metre standing start times).

II. A KERS FOR TWIZY? GO FOR IT!

"Twizy Renault Sport F1 serves quite simply as a bridge between the excellence of Renault's F1 technology and the brand's electric vehicle expertise. Carrying over racing technology for use with a production car without having to make major modifications to the latter was not as straightforward as it may seem and was a significant technological challenge. The development of Twizy Renault Sport F1 called for some very careful thought."
Guillaume Brotonne (Technical Manager, Twizy Renault Sport F1)

An electric vehicle which benefits from the combined technological expertise of Renault Sport Technologies and Renault Sport F1.

Renault Sport F1 and Renault Sport Technologies worked hand in hand to convert the KERS system for use on the Twizy Renault Sport F1 concept car and then fine-tune the resulting package.

Throughout the project, the collaboration between Renault's two sporting departments was exemplary, and the combination of their taste for a challenge, their passion for motorsport and their prior knowledge of Twizy was key to the project's success.

Based on an idea suggested by Renault Sport F1: thanks to the technological excellence it has acquired as a supplier of engines to a number of F1 teams, Renault Sport F1 wanted to communicate to a wider audience the savoir-faire it has built up in the realm of electric power thanks to KERS which became a part of the sport in 2009. Indeed, it was because of this very expertise that Renault's F1 engine specialists were called in to play a part in the development of the standard Twizy's electric motor in 2010. This grasp of the KERS used in F1 and of Twizy's electric motor provided the perfect opportunity to bring the two worlds together.

A project that hit the ground running
Flashback to the European F1 Grand Prix at Valence, Spain, on June 21, 2012. In the busy paddock, with the countdown to the race well under way, a discussion is taking place between three people in the Renault Sport F1 motorhome. Renault's KERS project leader Laurent Debailleul is talking about his involvement in the development of Twizy's motor and of the latter's parallels with racing technology. Almost as a joke, he says: "Why not fit Twizy with KERS?" Tarik Ait Said (Marketing Operations, Renault Sport F1) and Axel Plasse (Manager of Engine Engineering for the RS 27 V8 F1 engine) jump on the idea at once. The seed for Twizy Renault Sport F1 was sown, sparking off an immediate chain reaction...

Between the end of the summer and late-November 2012, Renault Sport F1, Renault Sport Technologies and Renault Design met frequently to evaluate the technical feasibility of the different options with a restricted budget. Their findings were then presented to Renault's senior management who gave the green light at the end of December. In less than four months, the idea was transformed into a project sanctioned at the very highest level of the company.

"From the moment the idea germinated and the first time Twizy Renault Sport F1 turned a wheel, only 10 months elapsed. This ultra-short development period was made possible by the passion and commitment of a small team of experts from different fields. From the outset, the spirit behind the project was worthy of that which prevails in Formula 1. By that I mean it combined passion, thinking outside of the box and a rigorous framework which allowed us to take it forward as a team, in addition to our everyday responsibilities."
- Tarik Ait Said (Project Coordinator, Twizy Renault Sport F1).

Renault Sport Technologies rises to the challenge: the Twizy Renault Sport F1 project was put in the hands of experts who have experience of low production-run Renault sporty vehicles. The specialists from Renault Sport Technologies had previously been responsible for the design and development of Renault Twizy's suspension and were also able to use their experience as the entity responsible for the Renault group's race and rally cars to work on this one-off project:
- Supply of a production Twizy.
- Development and adaptation of F1 components as a function of the architecture of Twizy's motor,
- Chassis modifications and fine-tuning.

"When Renault Sport F1 asked us to work on the project, our engineers didn't hesitate. Renault Sport Technologies had already made a significant contribution to the design and development of the highly innovative Renault Twizy which meant that our input was perfectly natural.

"Thanks to our experience of race car engineering, we were able to take elements from our FR2.0 and FR3.5 race cars and also check that the rigidity of Twizy's chassis and suspension was capable of handling the additional 60kW.

"Thanks to the very close working relationship we enjoy with Renault Sport F1, we were able to combine the 'fun' side of the project with some very advanced technology. We are very proud of the result."
- Patrice Ratti (General Manager, Renault Sport Technologies).

Meanwhile, the experts at Viry-Châtillon brought to the table their integration savoir-faire and KERS expertise, including the battery, not to mention their experience of Twizy's own motor.

"Thanks to our experience of KERS, we were able to guide the system's integration in the concept car and provide the necessary support for its fine-tuning development."
- Laurent Debailleul (Electric Systems Test Manager, Renault Sport F1)

An echo of the Espace F1...
Twizy Renault Sport F1 serves as an exciting bridge between the world of Formula 1 and that of production cars in much the same way as Espace F1 which was unveiled at the Paris Motor Show in 1994. This prototype was the fruit of a partnership between Renault and Matra and was produced to celebrate the 10th anniversary of Espace's launch. Its carbon fibre body was based on the design of the second-generation Espace.

Espace F1 used the same 820hp RS5 V10 3,500cc 40-valve engine as that which powered the Williams FW15C F1 car. It drove through a semi-automatic six-speed paddle-shift gearbox and the car was turned out in a striking yellow livery.

Comfortably strapped into bucket seats by three-point harness belts, the four passengers were able to enjoy a near-Formula 1 experience from the inside.

In addition to the fact that the two projects place the emphasis on 'fun', Espace F1 and Twizy RENAULT SPORT F1 both serve as eloquent illustrations of Renault's desire to see production vehicles benefit from technologies developed for motorsport. Thanks to its 35 years of experience as an F1 engine supplier, Renault benefits from an exceptional technological laboratory which provides it with an undeniable advantage when it comes to developing vehicles of tomorrow.

Technical data
Twizy Renault Sport F1 concept car / Twizy
Architecture: Asynchronous electric motor / Asynchronous electric motor
Maximum revs (rpm): 10,000 / 7,500
Max. power (kW/hp): 72/97 / 13/17
Main motor reducer gear ration: 1:9.23 / 1:9.23
Power gain due to the KERS: 80hp, available for 13 seconds / -
Maximum revs of the KERS (rpm): 36,000 / -
KERS reducer gear ratio: 1:3.6 / -
Top speed: 68 mph / 53 mph

An outstanding weight-to-power ratio
Twizy Renault Sport F1 concept car / Twizy 80 / Mégane R.S. / F1 car
Weight (kg): 564 / 473 / 1,387 / 650
Power (hp): 97 / 17 / 265 / 750
Weight-to-power ratio (kg/hp): 5.8:1 / 25:1 / 5.2:1 / 0.86:1

The people behind the project:

Renault Sport F1
- Tarik Ait Said (Marketing Operations Manager / Project Coordinator)
- Laurent Debailleul (Electric Systems Test Manager / KERS Expert for the Twingo RSF1 project)
- Axel Plasse (Programme and Renault Sport F1 Customer Support Director)

Renault Sport Technologies
- François Champod (Motorsport Technical Manager / Technical Project Coordinator)
- Guillaume Brotonne (Synthesis Engineer, Twizy / Technical Project Manager)

Renault Design
- Eric Diemert (Renault Sport Range Design Director / Project Manager, Design)

By Jonathon Ramsey