Although the real growth of hybrid car models around the world has been slower than expected, a most interesting development has come from Citroen – and it will be available in New Zealand almost immediately.
Called the Micro-hybrid, it’s a development which takes the best of what’s come out of regular hybrid technology, such as stop-start systems and regenerative braking, without the heavy (and expensive) storage batteries and their equally dear (and environmentally questionable) rare earth metals electric motors.
Available at launch on the new Citroen C4 e-HDI, the new micro-hybrid system incorporates a superfast stop-start system into a regular C4 with EGS transmission (electrically-assisted manual), using a dual function reversible starter-alternator that’s belt-driven to reduce power losses.
The car’s starter battery is partly recharged by regenerative braking, just like a hybrid’s, so each time you brake you pop some charge back into the battery, without calling on the alternator. Then when you stop – or even slow down, because it works at speeds under 8 km/h, unlike most stop-start systems–the engine shuts off.
At this point you’re using zero fuel, and emitting zero emissions.
And now here’s the really trick bit. We’ve noticed that even the best stop-start systems currently in use are a bit hesitant when you pull off after they’re been stopped, as they would be in traffic. In fact quite often an experienced driver will pre-empt the system when the lights are about to change to ensure you don’t balk and slow down the traffic behind you.
However Citroen’s system has two advantages which mean it’ll re-start within 400 milliseconds – coincidentally, about the time it takes a side airbag to inflate, or literally, the average speed of the blink of an eye.
One is that starter-alternator which, because it’s permanently linked to the engine (unlike a normal starter) starts cranking the engine over immediately it switches (automatically) to starter mode.
The second is a system called e-booster. This is a large capacitor linked directly to the starter. The capacitor is charged via regenerative braking, and when it’s fully charged power is diverted into the battery.
Unlike a battery, which feeds–out its power slowly but steadily, a capacitor has the ability to store large tracts of electricity within its compact dimensions, then feed it out in a hefty boost of power, whizzing the starter round at high speed and lighting up the diesel immediately.

In practice, this means you’ll never feel that hesitancy, never stall, and be ready to rush away from the lights using the 285Nm of torque (on overboost) from the super-economical 1.6 litre turbo-diesel engine.
Because it’s so simple compared to a hybrid, the C4 e-HDI, in luxurious Exclusive trim, still comes onto the market at less than $40,000, and can offer overall fuel consumption as low as 4.2L/100km (109g/km CO2 with Michelin eco tyres).
And that’s in a mid-size C-segment car (bigger than Corolla or Golf) with all the bells and whistles – including safety-oriented electronic stability programme, blind spot monitoring, and six airbags, as well as massaging front seats, variable intensity air conditioning, cruise control, cornering lights, Bluetooth connectivity, a big 380 litre boot – and a full 5-star Euro NCAP crash test rating which includes a 97 percent score in the “Safety Assist” category, the highest score for any vehicle of its type.
The final gamechanger is that because it’s a “normal” hatchback, without heavy batteries or electric motors, it rides, handles and LOOKS like one!