For the first time in-house, Kia has developed its own gasoline direct injection (GDI) engine.
The engine, which aims to reduce harmful emissions, is based on the new Theta II family of units that will power the next generation of Kia vehicles. The first is a 2.4litre four cylinder unit with a compression ratio of 11.3:1 that delivers 201ps at 6,300rpm. In its initial Korean domestic market specification it creates 25.5kg of torque at 4,250rpm.
GDI engines tackle the limitations of conventional fuel injections systems in which the valve opening and closing times get progressively shorter, reducing the time available to inject fuel, as the engine revolutions increase. By contrast, GDI engines position the fuel injector in the optimal location directly inside the combustion chamber. This in turn offers unparalleled precision.
Injection is also split into two phases to achieve optimum combustion: during the first phase, the pilot injection and ignition trigger the piston’s downward spiral stroke; and then in the main injection phase, more fuel is injected and ignited. This split technique reduces loading on the catalytic converter while helping to lower emissions. It is particularly beneficial during cold starts when emissions are normally highest because the catalyst has not yet reached its optimum temperature.
As an added bonus, a vehicle fitted with a GDI engine will achieve around 10 per cent better fuel economy than a car with a conventional multi-point fuel injected engine – precise figures vary based on the engine that is installed.
Kia’s version has been developed at a cost of £88million over a 46-month long research period and will make its Korean debut in the first half of 2010 before appearing in UK products in 2011.
