LocoDiscoBox (16+)

What have you planned for the festive season?

All images: group.renault.com

What’s the first thing you think of when considering gearboxes? Have you parked in gear? Does the manual action satisfy your taste? Is that a dog-leg set up? Why won’t the automatic change when I want it to? Where’s my Lego set? That latter, more pertinent point being what led to Renault seeking out a new way of changing gears. Settle in, pop it into D and grab your Lego Technic manual.

Christmas 2010 and we find Renault’s Nicolas Fremau, Powertrains and Hybrid expert, ordering boxes of Denmark’s most prodigious export. Not for his son, either. Fremau hit on the idea that the plastic cogs along with connecting rods could form the potential of a real world use gearbox for use in the coming hybrid/ electrification vehicles. The holiday period allowed him to indulge that buzzing feeling that engineers suffer from.

After twenty or so hours over several days fiddling around – and plenty of disbelieving glances from my son – I had made it. A Lego gearbox for the modern form of motoring. Now all I had to do was make it for real!

Shunning the back of envelopes and sophisticated programming for gluing, drilling and cursing, Fremau persisted over the winter break to assimilate hybrid engine and gearbox conditions, knowing full well he would require input from other Renault engineers; step forward controls specialist Ahmed Ketfi-Cherif, electric engine specialist Sid Ali Randi along with gearbox design specialist Antoine Vignon who not only added vital input but also the weight required by Top Brass to change the light from red to green.

Nicolas Fremau

Fremau offered his surprised but intrigued colleagues detailed explanations, and model analysis. Testing the Lego build, including carefully constructing their business case that management would then evaluate over several days, this formidable foursome came to the agreement that it would work.

Dropping a cog back, Fremau and his teams determination to produce such a transmission stemmed from management’s ideas of a smoother, more placid feel for electrically powered vehicles. Using just three gears in a dog clutch arrangement; that is using interference, not friction to engage matters. Those three gears would be set up for standard driving situations; City, Road and Motorway.

Two top brass the engineers needed to convince were Rémi Bastien and Gérard Detourbet (of Dacia and cost cutting fame) who, as M0 Director (entry level car range) would halt meetings with his, “Stop adding components and costs, think about removing, replacing or simplifying instead!” Fremau realised the difficulty in circumventing this brace’s unwillingness to change gear, as it were.

Armed with his Lego model and operating principles, Fremau and his team waited until the very end of a project meeting before delivering the goods. Fremau’s stars were in alignment; the idea, which turned out to be Renault’s cheapest prototype component in its long history was given the green light. Detourbet, clearly elated, exclaimed; “If you can make this out of Lego, it just has to work!

Thus began a fourteen month project, requiring a dedicated team along with many changes to what had become known as the LocoDiscoBox, subsequently rather corporately re-named E-Tech. Fremau’s revised Lego parts now required manufacturing in scaleable form; electric would be the vehicles main source of drive with the ICE power seamlessly entering the fray at higher speeds.

Promoted to the M1 category, that is the ultra competitive, versatile compact class, the Mégane was chosen for calibration and testing purposes. Changes to the LDB were soon required. With Alliance partner Nissan providing the HSG Powertrain (High-voltage Starter Generator), there to regulate battery charge alongside smoothing out those gear changes, the engineers realised a fourth gear would be favourable for motorway speeds.

This fourth gear would disengage the electric motor, reducing drag and consumption. Add in a smaller electric motor for low speed manoeuvres equated to smaller, lighter components; manna from heaven for engineers. Some Formula One know how also wormed its way into the game utilising KERS ideas to assist with regenerative braking alongside smoothing out the entire process of electrical motion. The Eolab from 2014 allowing glimpses toward an electrified  future.

Fremau’s Christmas a decade ago may have been far from conventional but the results are there for all to see. “Even with the green light, we had lots of it’ll never work comments and let’s face it, this was a crazy idea. With plenty of self-motivation and good backing, over time the whole company began to take this on board seriously to the point that me and my team are most proud of our achievements.

Today, the E-Tech is available in the Captur plug-in Hybrid, the all new Clio and Mégane Sport Tourer and continues to move forward a-pace. Though one can’t help wishing for the original name to have been kept, but we close today with a piece of advice. Should your child (of whatever age, though Technic seems to be 16+) show an aptitude for meddling with Lego, encourage and allow exploration but best to wear stout foot coverings when creating such innovations – hospital staff prefer quieter Christmas’s.

Author: Andrew Miles

Beyond hope there lie dreams; after those, custard creams?

8 thoughts on “LocoDiscoBox (16+)”

  1. Thanks for bringing this to my attention, Andrew. A gearbox without clutches is an interesting concept and I love the story how this came about. This system uses one electric motor to accelerate from standstill and a second electric motor will start the engine and rev-match it as well. The first electric motor also is used for driving backwards as there is no reverse gear.

    I can’t help it, but I’m very intrigued by this idea. I bet the electric motor will also assist in overcoming the big drop in revs when shifting as their are fewer gears. The significant drop in revs will sound a bit strange to my ears at least, but I bet one gets used to that rather quickly. Not interested in swapping cars at the moment or even in Renault to be honest, but I hope to make a testdrive one of these days.

    1. Freerk, the motor indeed assists in filling in the “gap” between gearchanges. I’ve read reviews of e-tech equipped cars and they mention that the gearchanges are almost imperceptible. The significant drop in revs you might expect doesn’t happen, because the four gears correspond to the upper four in a six speed, the electric drive taking the place of first and second and the gap between them.
      There is one exception though. Plug in cars spend a significant amount of their time in electric operation (that being their reason for existence after all!) and as there are two electric gears there is one change to be made. In this case there is no other source of power to maintain momentum and so there is a significant pause as one gear disengages and the other engages. Renault could in principle opt to use the engine for this purpose I suppose but I guess this would feel and sound strange indeed.
      My internet searching revealed to me quite a lengthy dissertation on the subject of but unfortunately it’s en français. If you want to have a go, here it is: http://www.fiches-auto.fr/articles-auto/hybride/s-2290-fonctionnement-de-l-hybride-e-tech-renault.php

  2. Great stuff, Andrew, although reading the about technical complexities made my head hurt a bit! Interesting to hear that engineers are physically building conceptual designs rather than just doing everything virtually, as I would have assumed.

    As a child, Lego was my favourite toy, although my experience pre-dated the ‘Technic’ era so everything I built were, er, buildings. My (75 year-old) next-door neighbour loves Lego and has built lots of model cars from the kits.

  3. This is a fascinating idea. When I first heard of e-tech I had to spend quite a time (well, lockdown and all that) to find out how it actually worked because neither Renault’s publicity nor the articles written based thereon actually explained it. Everything suggested a six speed gearbox whereas it’s actually a four speed with six ratios. Eh? The motor uses two gears (second and fourth as I recall) and the engine all four, but it engages with the shared gears via intermediary gears which result in a different ratio. Interestingly the motor can engage any of its gears at the same time as the engine engages any of its four so you can have both power sources driving through the same gear.

  4. What an excellent article Andrew which I really enjoyed. Good to read something a bit different I feel so thank you.

  5. Brilliant article Andrew. When I started reading it, I thought, a gearbox made from plastic? But all was revealed. It’s fascinating how these ideas come to fruition. Thanks to DP too for explaining how it actually works. I did “O” level Motor Vehicle Studies, yes, there was such a topic back in my day, so I know how a manual gearbox works and to a lesser extent, a conventional automatic, but that was before the days of computer controllers. Thank you both for very interesting reads. Made my lunch time much better.

  6. The 1988 Jaguar XJ220 prototype came about in very similar circumstances. It’s the old story. Engineer kicking his heels over the festive break; dazed by food and bored with the telly, gets idea. Acts on idea. Does his calculations on some used wrapping paper. Builds chassis and internal structure over Christmas break in dining room using waste cardboard. The rest you know…

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