The three-cylinder Ford 1.0-litre Ecoboost engine is to be offered with fuel-saving cylinder deactivation technology that will enable it to operate as a two-cylinder unit.
Similar technology is seen on many four-cylinder engines, but Ford claims this is the first time it has been engineered into a three-pot. Some manufacturers have dismissed the idea, citing refinement as one of the main issues, but Ford hasn’t been deterred.
Cylinder deactivation will automatically stop fuel delivery and valve operation for one of the engine’s cylinders under conditions where full capacity is not needed, such as when coasting or cruising with light demand on the engine. The technology can disengage or re-engage one cylinder in 14 milliseconds.
Capable of operating at speeds of up to 4500rpm, the system uses engine oil pressure to activate a special valve rocker and interrupt the connection between the camshaft and the valves of cylinder number one. Software uses factors including speed, throttle position and engine load to determine when to deactivate the cylinder.
The 1.0-litre Ecoboost - first introduced in 2012 - has a new single-piece camshaft module that has freed up space within the cylinder head for new oil channels and valve-switching componentry.
Ford engineers predict that the system will be active for a few seconds at a time in most driving scenarios and has the potential to improve fuel efficiency by up to 6%.
Installed in the current Fiesta, the 1.0-litre Ecoboost in 98bhp form is capable of a claimed combined economy of 65.7mpg, so a 6% improvement could take that figure to 69.6mpg.
Ford said it has “devised advanced solutions to counteract vibrations and ensure that cylinder deactivation is imperceptible to drivers in terms of operation and engine performance”.
The technology will be tested throughout 2017 and be made available for sale in 2018, although Ford hasn’t confirmed which car model will be the first to benefit from it. At present 11 Ford models – the Fiesta, Ecosport, B-Max, Focus, C-Max, Grand C Max, Tourneo and Transit Connect, Tourneo and Transit Courier and Mondeo – are available in Europe with the three-cylinder engine.
With the 1.0-litre Ecoboost available in three power ratings, Ford also has yet to confirm which of them will receive the cylinder deactivation technology.
The system uses an offset crankshaft configuration and deliberately ‘unbalanced’ flywheel and pulley that counteract vibration. The new dual-mass flywheel and a vibration-damping clutch disc help neutralise engine oscillations when the engine is running on two cylinders, especially at lower revs, and enable a wider operating range.
Intake and exhaust valves are closed when the system is active, trapping gases to provide a spring effect that helps balance forces across the three cylinders for refinement and also retain temperatures inside the cylinder that maintain fuel efficiency when reactivated.
New engine mounts, drive shafts and suspension bushes also will be specially tuned for refinement when the revised 1.0-litre Ecoboost is installed in a car.
The engine has also been made more durable to cope with the different loading forces resulting from cylinder deactivation, with uprated parts including a new camshaft chain, and valve rockers formed using advanced metal injection moulding.
The system was developed by Ford engineers in the UK, Germany and US, in collaboration with the Schaeffler Group, an engineering partner.
Bob Fascetti, Ford Motor Company’s global powertrain engineering boss said the engine was proof that "there is still untapped potential for even the best internal combustion engines to deliver better fuel efficiency for customers.”