Monday, 16 March 2015

Volvo to launch three-cylinder in 2017

 Volvo is set to launch a 1.5-litre three-cylinder gasoline engine in 2017 using components from its 2-litre four-cylinder unit.

Using the model of 500cm3 per cylinder, Volvo engineers in Gothenburg have extended their four-cylinder engine family downwards to create an aluminium three-cylinder engine with a balancer shaft to give the NVH behaviour (especially rotational balance) demanded by Volvo customers of their vehicles.

The 500cm3 per cylinder model allows the company to take advantage of commonality and speed of development as component and systems suppliers signed up for the 2-litre are already effectively signed off for the three-cylinder unit.

The swept volume size of 1.5-litres suggests Swedish engineers have set BMW’s 1.5-litre three-cylinder as their benchmark; an engine they have to at least match or improve on. They will also have fully analysed Ford’s three-cylinder EcoBoost gasoline engine – another benchmark in its own right as it was the first to appear in 2012. Its elegant mix of rotational balance (three-cylinder engines have lower secondary-order vibrations than four). good thermal and space efficiency plus its suitability for turbocharging) ensured EcoBoost a good rating - and top marks for Dunton.

The choice of 500cm3 per cylinder, part of Volvo’s Engine Architecture (VEA), as well as aiding purchasing and cost-benefit, allows Volvo to put the three-cylinder down the same production lines as its stable-mate.

Engineers are looking for a specific power of least 100bhp/litre – even 120bhp/litre – and a specific weight of around 1kg/bhp from the new product which will have turbocharging. The latter would make feasible a 100kg engine. Could engineers in Gothenburg even have set their sights on 100kW/litre as well as meeting Euro 7 emission requirements?

The engine has passed the concept stage – so is now effectively frozen – and engineers are in the rig and vehicle testing stages. Engineers at Geely Automotive – Volvo’s owners – in China are up-to-speed with the programme but what input they have, if any, remains to be seen, as Volvo can rightfully claim a long history in European engine development – both gasoline and diesel.

Mention of the word diesel raises the prospect that at some stage a further element of the VEA programme could bring to pass a diesel derivative with possible hybrid overtones. In the meantime, it looks as though Volvo is set to follow Ford, BMW, Peugeot-Citroen, Renault, Opel/Vauxhall, Volkswagen (gasoline and diesel) and more recently Kia Motors with a three-pot gasoline engine.

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