General Motors Europe has introduced its first Euro 4 emission-compliant diesel car model, the Opel/Vauxhall Astra 1.7 CDTi, claiming better performance, greater running smoothness and “greatly reduced” exhaust gas pollutants.

The 1686cc 16v 80PS four-cylinder EcoTec turbo diesel, with two overhead camshafts and common rail direct fuel injection, produces a maximum torque of 170Nm and a top speed of 108mph in saloon and hatchback models.

Combined cycle fuel consumption is 61.4mpg (58.9mpg for the estate version). Extra aerodynamic drag and roll resistance features in the Astra ECO variant increase fuel efficiency to 64.2mpg – and raise top speed to 111mph.

Deliveries of the Astra models with the new 1.7 CDTi engine begin next spring.

The achievement of the Euro 4 emission standard gives the models favourable company car and vehicle excise tax treatment in the UK.

GME claims the Astra 1.7 CDTi is the first diesel to meet Euro 4, mandatory in all new car types from 2005, without the need for expensive and complex additional emission gas treatment.

Second generation Bosch common rail direct injection is a technical highlight of the new engine, increasing the injection system pressure to 1,600 bar, and improving control of the injection process.

Other new features include:

* Pneumatically guided swirl valves in the intake tract that help bring the fuel-air mixture to a high swirl rate at low rpm. This leads to efficient combustion and high torque. At high rpm the swirl is reduced, improving performance.

* An electrical linear EGR valve serves as an additional air restrictor, providing precise regulation of the returning exhaust gases. By restricting the air flow when the engine is shut off, the throttle valve also eliminates the so-called “shut-off kick”.

* Water-cooled exhaust recirculation lowers the temperature of recycled exhaust, cutting NOx emissions.

“The 1.7 CDTi ECOTEC engine successfully restricts both particle and nitrogen oxides emissions to the area in which they are produced, thus reducing exhaust emissions,” said Opel Powertrain managing director Rita Forst.

She said the engine can be introduced into the market in smaller cars in large numbers.

“The Astra 1.7 CDTi is the first model in Opel/Vauxhall’s comprehensive diesel offensive. During 2003 another three all-new diesel engines will be introduced, each of them at the top of their respective segments from a technological standpoint,” said Vauxhall chairman Kevin Wale.