25 Jun 07
CCS needs a new type of fuel
Henry Ford once said: 'If I had asked my customers what they wanted they would have said, "A faster horse".' He had a point. These days they call it 'thinking out of the box' and without it that's just where iconic products like the Sony Walkman, the personal computer and the iPod would have stayed.
Volkswagen also thinks Henry had a point, and recently offered to spill the beans to 4Car on some of the innovations they have in the pipeline, from greener engines to enhanced driver enjoyment to child-friendly passenger compartments. Top of the agenda is climate change. No surprise there, but some of the ideas for combating it are far from obvious.
One is CCS, or Combined Combustion System. Almost identical to a diesel engine, the difference lies in the way fuel and air are mixed 'homogeneously' inside the engine to remove all traces of soot and dramatically reduce the toxic nitrogen oxides that constitute one of the main pollutants in car exhaust fumes. However, for CCS to provide maximum benefit, it needs a new kind of synthetic designer fuel currently under development by VW and others. SynFuel is made from natural gas, while SunFuel is made from plant matter known as biomass, or by processing straw.
Clean as a petrol engine, frugal as a diesel
SunFuel is cleaner than petrol and diesel and is CO2 neutral because the plants it is made from absorbed the greenhouse gas when they were growing. But these new biofuels are in their infancy and VW experts expect it will be 2015 before they go on sale in any quantity.
Another new engine design called GCI, for gasoline compression ignition, combines the fuel economy of a diesel engine with the low emissions of a petrol engine. It works by switching between the spark-plug ignition of a petrol engine for starting and hard acceleration, and the sparkless compression ignition of a diesel when cruising gently. GCI can burn both petrol and SunFuel, and the next stage is to combine the technology with VW's TSI engine, which has both supercharger and turbocharger. The prototype we tried drove smoothly, with only the slightest rattle giving away the engine's switch from petrol to diesel mode, a small computer screen in the dash illustrating which of the two you are in.
