There is a summertime treat in store for the Vauxhall Zafira Tourer – it gets a newly developed 1.6-litre diesel engine that will be full of hidden promises.

Vauxhall describes the CDTi ECOTEC unit as downsized and so it is but only modestly, because it replaces the company’s long-established 1.7-litre.

It will meet the demands of Euro 6 emissions (the first Vauxhall diesel to do so) and see fuel consumption cut by 10 per cent compared to comparable 2.0-litre cars, says Vauxhall.

It promises to go much further, though. Developed by Vauxhall’s parent General Motors in Turin (that’s where Italian diesel engine maker VM has its HQ), Germany and the USA – which is moving slowly towards more diesel acceptance – the engine has been designed to achieve class-leading low levels of noise, vibration and harshness (NVH).

Several versions are scheduled but the initial application in the Zafira Tourer will see it turning out 134bhp and a hefty maximum torque figure of 236lb ft.

Vauxhall singles out its weight-saving aluminium cylinder block and closed loop combustion control (CLCC) for special mention.

CLCC makes a very significant contribution to combustion efficiency, providing comprehensive cylinder pressure information for the engine management system. This makes for the creation of more focused algorithms that can help to generate more accurately, the fuel injection profile and adapt it to varying conditions.

This flexibility is able to provide the levels of precision needed to meet required fuel burn profiles. It controls the rate of fuel burn, allowing not only consumption and emissions to be trimmed to optimal levels, but also to reduce that bane of the diesel engine – noise.

For an “international” engine given fuels of varying quality to burn, it helps to automatically achieve impressive levels of efficiency.

And all that with existing injection technology. It isn’t exactly something for nothing but it is something for not too much spending.

Vauxhall is confident that the new engine will be rated as a class leader and that its broad availability of required power outputs and high torque levels, will provide the sort of figures that make the company’s powertrains highly competitive in a very tough sector.

Vauxhall states that it plans to launch three all-new generations of petrol and diesel engines. Its sister-company Opel plans to introduce 23 new models and 13 new powertrains by 2016, most of which (with the exception of compressed natural gas (CNG)) will be available in the UK.

The diesels will have to vie with increasingly downsized petrol units, including a three-cylinder 1.0-litre unit that is expected to become available mid-way through next year, but diesels will not downsize to that level.

For reasons of cost-effectiveness and NVH, between 1.2 and 1.3-litre capacity is about as small as its powertrain engineers regard as viable.

Stuart Birch