The old motor roars back

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Small cars sometimes struggle to climb steep hills. But a converted Chevrolet Lacetti has something special to help it along. Instead of having to keep changing down and revving harder to ascend a winding Alpine-type test track, the engine can cruise almost to the summit in top gear. This is because the car benefits from one of the developments that in these more economical and greener times promises to give the petrol engine a new lease of life.

Old technologies have a habit of fighting back when new ones come along. This is not surprising because they often have an enormous amount of design, engineering and production knowledge invested in them—especially so in the case of car engines. So new hybrid systems, fuel cells and electric motors will be chasing a moving target. The internal combustion engine will be getting better too.

The Lacetti is just one example. It gets its extra oomph from a supercharger forcing more air into the combustion chambers of its engine. This is an old idea that used to speed up 1920s racing cars, like ‘blower’ Bentleys. But their engines tended not to last very long. With stronger engines, superchargers have been staging a comeback in big cars. The one in the Lacetti is different: it is a dual-speed supercharger that provides its highest boost at low speeds. This gives the car a huge 40% increase in torque, or pulling power.

The car was fitted with the device by its developer, Antonov Automotive Technologies, a British company. The supercharger is purely mechanical and uses planetary gears to change speed. Antonov reckons that 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.

Car engines (racing cars aside) have long been a compromise between efficiency, power and durability. Greater flexibility has come with fuel injectors, which can metre fuel more precisely than carburettors, and variable-valve control, which 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 V8 and V6 engines to shut down a few cylinders when driving slowly.