What is it?
This is a late pre-production prototype of the big Vauxhall Zafira Tourer MPV, powered by the company’s all-new 1.6-litre turbodiesel engine. At the recent technical seminar for the Vauxhall-Opel’s new powertrains and transmissions, company engineers were very upfront about the failings of the current diesel engine range and the inadequacy of the manual transmissions.
Until now, Vauxhall has mostly used diesel engines based on existing units from Fiat and Isuzu. Indeed, Vauxhall-Opel had a Powertrain Engineering centre in Turin, which was born out of its alliance with Fiat.
GM Europe retained the facility, which now employs 1000 engineers, although project manager Gianmarco Boretto says that GM engineers from around the world were involved in development, which needed ’90 million’ Finite Element computer calculations.
Boretto says the clean-sheet project to create a mid-size diesel engine family began in 2008. The primary aims were to achieve ‘class-leading’ power density and for the unit to become a benchmark for low ‘noise, vibration and harshness’.
The final production engine is based around an aluminium block and a single, water-cooled, variable geometry turbocharger. Twin balancer shafts - mounted in the block - will be optional, depending on which market the engines are aimed at, but it seems likely that they will be fitted the UK-spec Vauxhalls.
The direct-injection system operates as high as 2000bar and it uses eight-hole injectors. These injectors can make as many as 10 ‘pre-injections’ in each piston cycle, which is one of the ways of reducing the distinctive ‘diesel rattle’.
To help speed warm-up, the engine’s water pump can be disabled via an electromagnetic clutch. Boretto also claims that the new unit has the lowest internal friction of any current engine (a calculation expressed by ‘Friction Mean Effective Pressure’) and develops 1kw of power per 1.49kg of weight, also a claimed best-in-class figure.
In order to meet the super-stringent EU6 pollution regulations due in Sept 2014, the engine can be fitted with either Selective Catalyst or a Lean NoX Trap, depending on the size of the host vehicle. A ‘close-coupled’ Diesel Particulate Filter is fitted to all versions of the engine, its design and positioning make it easier to ‘regenerate’ and burn off the exhaust soot that it traps.