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| Citroen's Stop-Start system gives lower emissions and fuel consumption in traffic |
Advances just entering into the motoring mainstream include Displacement on Demand, stop-start and hybrid technology. Displacement on Demand (DoD, or cylinder shutdown) is arriving in high-performance, large-engined cars like the Chrysler 300C HEMI. Cadillac first tried this out in the early 1980s on the Eldorado 4-6-8, so called because it could run on four, six or eight cylinders depending on demand. It was a resounding non-success, but this time round, it looks to be a go-er. In a similar concept to the Cadillac V8, the HEMI 5.7 V8 (so named for its hemispherical-shaped combustion chambers), four out of the eight cylinders imperceptibly shut down when the car is cruising, yet kick in again when the throttle is pressed more urgently. The fuel consumption gains aren't spectacular, but in a car that would otherwise struggle to do 20mpg, every little helps. Expect to see it appearing in new 4x4s and large MPVs, as well as in large-engined luxury models and sports cars in the not-too-distant future. As with so many new advances, the cost of fitting such technology is initially high, limiting it to expensive, top-end vehicles, but it should gradually appear in a wider variety of ranges.
Stop-start, however, has made its debut at the other end of the car market. Volkswagen used such a system in its rather disconcerting Golf Eco of the early '90s - it didn't take off - but it has since been honed and resurrected by PSA Peugeot-Citroen. As its name suggests, the C3 Stop-Start (with the 1.4i petrol engine and SensoDrive clutchless gearbox) cuts out when you come to a halt at traffic lights or in slow-moving traffic, and re-starts itself when you want to start off again and lift off the brake. It's an effective and cheap way to reduce fuel consumption - Citroen claims 15 percent savings in the C3 - and should soon feature in many more Peugeot and Citroen ranges.
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