Citroen’s new stop-start system revealed

By Tim Pollard

Motoring Issues

08 October 2008 13:12

Citroen has shown off its next-generation stop-start system on a C3 Picasso. The company launched its first-gen system four years ago on the C2 and C3, for which it claims fuel savings of up to 27 percent, but it’ll soon be superseded by a new, cheaper system.

The second-generation Stop & Start will be launched in 2010 on PSA’s small petrol and – for the first time – diesel models. Citroen claims the C3 Picasso equipped with this tech will top nearly 70mpg on the combined cycle and emit just 110g/km of CO2.

The new tech is a refinement of today’s combined alternator-starter unit, which has been fettled to start more quickly and smoothly, claims Citroen. But crucially, it’s also much cheaper to build. Which is a good thing, as Citroen UK only shifted 100 stop-start models last year, out of 100,000 new cars sold.

Economy gains are made because the new system mirrors that in the Mini, which decouples the alternator during braking or coasting, thus stopping the engine labouring unnecessarily.

The Mk2 Stop & Start is much simpler – and hence cheaper – to manufacture. The system in today’s C2 and C3 is horrendously complex, with a belt-driven alternator-starter unit and an additional battery required to provide the necessary charge. Although the exact technical details haven’t been announced yet, the new one uses fewer expensive parts.

PSA as a group has pledged to have more than 1.1 million stop-start vehicles on the road by 2011. Today it manufactures around 3 million cars a year, suggesting we’ll see the tech spread to a good proportion of its model ranges.

By Tim Pollard