27.11.2002
Twinport technology makes the Astra even more economical

A groundbreaking innovation for smaller four-valve gasoline engines reduces fuel consumption by as much as 7%. The new Twinport concept debuts in the 1.6 ECOTEC engine in the Astra sedan, station wagon and convertible.

Starting next spring, Twinport, the fuel-saving technology for smaller four-valve engines, will be used with the 1.6 ECOTEC engine for the first time. Variable inlet camshaft control and a high proportion of exhaust gas circulation in this engine, which is used successfully in millions of cars today, resulted in a 6% drop in fuel consumption.

Twinport is recognized for efficiency and already meets the Euro 4 emission standard. Detailed optimization by Powertrain engineers led to a further 1% improvement in fuel consumption. This fuel-saving technology will also be available for other ECOTEC engines with displacements of 1.6 liters and in other model lines in the future.

Twinport fits Opel's strategy of offering advanced technology at affordable prices. For example, the Astra 1.6 two-door hatchback (74 kW/100 hp) with manual gearbox, consumed only 7.0 liters per 100 kilometers through the entire MVEG test cycle. It now needs only 6.5 liters of unleaded premium gasoline per 100 kilometers with the 1.6 ECOTEC 76 kW (103 hp) engine.

The Twinport principle is based on the ECOTEC four-cycle spark ignition engines and uses innovative methods to minimize the so-called throttle losses. These occur because the power output is governed by varying the fresh air supply to the inlet ports. In the new engines this induction resistor is skillfully reduced. At partial load, the four-cylinder engine receives up to 25% of its cylinder charge from previously burnt exhaust gas delivered through an additional line.

A major advantage of Twinport technology results from the fact that the conventional three-way catalytic converter remains in tact. This sets it apart from stratified-charge direct gasoline injection, which works with lean mixtures and requires an additional catalytic converter for the oxides of nitrogen. In addition, retention of the inlet pipe fuel injection reduces technical complexity and, consequently, the cost to the customer. This favorable cost situation makes the Twinport principle particularly attractive for compact-class cars, as power output and efficient fuel consumption are fully maintained.