1.Supercharger forces more air into the combustion chambers of engine. A new dual-speed supercharger provides its highest boost at low speeds, and thus gives the car a huge 40% increase in torque, or pulling power. The supercharger developed by Antonov Automotive Technologies, a British company, is purely mechanical and uses planetary gears to change speed. As claimed, it could be used to reduce the size of a car's engine by up to 50%-so it would use less fuel and produce fewer CO2 emissions, but still provide good performance. 2.Fuel injectors can metre fuel more precisely than carburettors, and variable-valve control can optimise the opening and closing of inlet and exhaust valves to produce more power when accelerating or greater economy when dawdling around town. The same systems are also used in some big and thirsty engines to shut down a few cylinders when driving slowly. 3.The e-Valve system is new development made by Valeo, a French automotive supplier. It uses electromagnetic controls to open and shut valves instead of pushrods operated by a camshaft. As each valve can be operated independent of any other, all sorts of tricks become possible, including shutting down cylinders and switching temporarily from the traditional four-stroke Otto cycle (as developed by Nicolaus Otto, a German engineer in 1876) to a type of Atkinson cycle (an ultra-lean system invented as a rival in 1882 by James Atkinson, a British engineer, but which suffered from a lack of power). As Valeo reckons, on average their e-Valve system can cut fuel consumption and CO2 emissions in a car by up to 20%. It could also be used to make three- and two-cylinder engines that run efficiently and smoothly. 4.Fiat's new valve-control system, Multiair, uses hydraulics and electronics to optimise valve settings. When combined with a turbocharger (a supercharger driven by exhaust gases). The system can produce a "downsized" two-cylinder engine that can perform like a bigger four-cylinder one, but with fuel savings of some 20%. 5.Daimler's DiesOtto engine will use a combination of variable valve-control, fuel injection and turbocharging. 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 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. 6.Ricardo, another British automotive-engineering company has been working 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.