Fiat is investing heavily in smaller engines with its new valve-control system, Multiair. This uses hydraulics and electronics to optimise valve settings. When combined with a turbocharger (a supercharger driven by exhaust gases), Fiat engineers talk of producing a “downsized” two-cylinder engine that performs like a bigger four-cylinder one, but with fuel savings of some 20%. Fiat is expected to start using Multiair engines in its cars in a year or so.
Using a combination of variable valve-control, fuel injection and turbocharging, Daimler is developing an entirely new type of engine. It can switch between operating as a petrol engine, with agility and power, to operating as a diesel, with economy and torque. The DiesOtto engine, as Daimler has called it, starts as a petrol engine with spark plugs igniting the mixture of fuel and air in its cylinders, and remains as a petrol engine when high performance is needed. But at low and medium speeds the engine switches into diesel mode, in which the fuel is ignited by compression and heat alone. A 1.8-litre four-cylinder test version of DiesOtto fitted to a prototype Mercedes S-class saloon produced plenty of power, but also returned an average fuel consumption of 5.3 litres per 100km (equivalent in America to 44.4mpg)—extremely good for a such a big car. The vehicle’s emissions were also lower.
In a similar vein, Ricardo, another British automotive-engineering company, has been working with a group of partners on an engine that can switch from four-stroke to two-stroke running. Two-stroke engines can provide very high levels of torque. Ricardo reckons such an engine could not only improve fuel economy by 27% over a traditional engine but also greatly reduce its size and complexity. And because small engines take up less space in a car, that means there will be more room for occupants, inviting more innovative designs.
By putting all these technologies together, small cars capable of breaking the 100mpg barrier will become possible. Getting more than 80mpg from some small diesel-powered cars is already feasible—with a very light foot on the accelerator. Indeed, according to Edmunds.com, an automotive-information service, when you count the overall costs of owning a car, only one hybrid in America, the Honda Civic Hybrid, gets into the top ten of the least expensive vehicles to run, with fuel prices at $5 a gallon. It may be old hat, but the internal combustion engine still has a lot of mileage in it.
From :Economic Times.
