Renault doing a hybrid? I thought it was betting on electric.
It was. Back in 2012 it launched the Zoe and expected big electric sales. It didn’t happen. Not fast enough. And diesel is no good for superminis – too dirty unless too expensive. So Renault has invented a hybrid system, called E-Tech.
You mean copied Toyota’s?
Absolutely not. This one has fixed gear ratios, not Toyota’s ‘power-split’ epicyclic CVT. It’s also very different from the Golf GTE’s system which has a DCT transmission.
My lengthier technical explanation is hidden behind those underlined blue words.
Why did they do it like that?
Because it’s a cheap and light system. The transmission is conceptually complex but mechanically simple, and it’s matched to a cheap non-turbocharged engine, because the electric motors do what a puffer would do – improve mid-range torque. So it’s likely to undercut a diesel auto both in price and weight.
Have you had a drive?
Yes, on a late prototype that was said to be 95 per cent sorted in normal mode, but its sport mode calibration still needed work.
So how does it feel?
There are no clutches, so it always moves away from rest by electric power alone. Also, there’s no reverse gear in the box, so again going backwards is done by electricity. (You can reverse an electric motor but not a petrol engine.
After that, the petrol engine is started up by a second smaller electric motor, and that motor also helps match the engine’s revs to the road speed in first gear, so it can engage the gear in this no-clutch mechanism without bump’n’grind.
So does it feel like a regular auto when you accelerate?
To an extent yes. In each of the four gears, road speed is proportional to engine speed, so there’s no rubber-band effect. Having just four gears means the ratios seem a fair way apart.
What about the performance?
With the engine and electric motors running together, you’ve got 140bhp. So it goes pretty well. The engine is a bit rough when you floor it at very low revs, but otherwise quiet, partly because it doesn’t spin to high rpm – the system changes gear to keep it at middle revs where it’s most efficient. Sometimes kickdown can feel a bit laggy, but otherwise it’s all very sanitary.
I’d rather have it than a diesel. There’s even a sport mode, which runs the engine more often to make sure you’ve always got a buffer of battery to give a nudge of electric torque.
Can it drive engine-off?
Yes, and it does. In city traffic, its strategy is to run full-electric for a few minutes. Then it starts the engine and recharges the battery. This is the most efficient way, because the engine is either running at its most efficient rev range, or it’s shut off. No idling or light-throttle running as those waste fuel.
Overall, Renault says in city traffic it’s all-electric for 80 per cent of the time. Although obviously not 80 per cent of the miles because the time keeps ticking on even when you’re going precisely nowhere. This amounts to a 40 per cent city fuel saving, goes the claim. Though at cruising speed the savings are not much at all.
Even when the engine is running and you think you’re using a light throttle via the pedal, the management system works the engine hard, dragging it via the motor/generator units to charge the battery.
Sometimes, if the battery is getting low and the system calculates you won’t be able to do an electric re-start, it puts the engine’s transmission into neutral and runs the four-cylinder to generate some charge. It’s a strange drone, but not loud enough that your music wouldn’t drown it. So despite the fact it moves away under electric power, the engine might at that moment be running – but it’ll be connected to the battery rather than to the wheels. In fact at less than 9mph the engine is never driving the wheels directly.
Well, one thing. One of the system’s main parameters is battery charge. So if the battery is low, a certain pedal input on your part, at a certain speed, will probably get you lots of engine power and a low gear. If the battery is charged, exactly the same accelerator position and speed will get the same performance via the electric motor only. In between, you might get the engine come on but in a higher gear.
In other words, unlike a normal autobox car, you never quite know what sound you’ll hear when you make a certain right-foot demand. But you’ll always get the acceleration you expected.
Does it have sulky hybrid brakes?
Renault has spent money on a true blended brake system, using regeneration where possible rather than the friction brakes. And yes those designs can often cause inconsistent pedal response and feel. But here it’s pretty good.
Will it be just for Clios?
Nope, there’s a Captur coming as a plug-in hybrd, and later a Megane. The Clio has a 1.2kWh battery and runs at 230V. The Captur has 9.8 kWh battery so it can go about 35 miles (approx. 56km) on electric drive alone. Although the PHEV’s engine, transmission and motors are the same as the Clio, the whole system runs at 400V to give extra power for driving electrically.
Words: Paul Horrell