Twinport technology builds on the standard four-valve technology of ECOTEC engines. Savings are achieved via a variable intake manifold in combination with a high rate of exhaust gas recirculation. Under ‘partial load’ the engine receives an additional 25 per cent of its fuel air mixture from the already burnt exhaust gas recycled back into the mix.
The advantages of twinport technology are achieved through a combination of fuel injection and exhaust emission control by three-way catalytic converter technology. This reduces technical complexity and consequently the cost to the customer, making the twinport solution particularly attractive for compact-class cars, as power output and efficient fuel consumption are maintained.
Average fuel consumption of the new twinport engines is remarkably low. The 1.0 litre engine when fitted in the Corsa achieves 49.5 mpg on a combined cycle, while the larger 1.4 90 hp unit returns 44.5 mpg – using nearly 13 per cent less fuel than its predecessor with a five-speed gearbox.
When combined with the Easytronic transmission the new 1.4 twinport engine achieves savings of over 23 per cent compared with the current model.
2.2 DIRECT ECOTEC
For larger displacement petrol engines Vauxhall is using direct injection technology to increase fuel efficiency, the first being the 155 hp 2.2 DIRECT.
Based on the 147 hp 2.2 16v, the petrol direct injection works with variable injection pressure (40 to 120 bar) and a variable intake system. With the engine operating under partial load, fuel consumption is low because of the high levels of exhaust gas recirculation. On average fuel consumption is six per cent less than the conventional
2.2-litre engine, yet the new engine produces up to 10 per cent more torque at low revs (220 Nm at 3800 rpm compared with 203 at 4000) and has six per cent more power (155 hp compared with 147 hp). Following its debut in the Vauxhall Signum, the 2.2 Direct will also be available from launch in the new Vectra Estate.
1.3-Litre Common Rail Diesel For Agila and Corsa
The new 1.3 CDTI ECOTEC (70 hp and 170 Nm at 1750 to 2500 rpm) is currently the smallest common rail diesel engine, and will be available in the autumn in the Corsa and Agila. Its technology provides for economical fuel consumption, (58.3 mpg in the Corsa and 50.5 mpg in the Agila) environmentally friendly exhaust emissions (Euro 4) and smooth, quiet running.Published 20 June 2003